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  • ASTROPHYSICS  (9.206)
  • EARTH RESOURCES AND REMOTE SENSING  (4.547)
  • Witterung
  • 1990-1994  (7.505)
  • 1980-1984  (6.248)
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  • 1
    ISSN: 1871-4528
    Schlagwort(e): Klima ; Witterung ; Qualität ; Trockenheit ; Sorte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Summary The effect of chitting and planting time of potato seed on the suitability of the crop for crisp production was investigated in a 5-year trial. The second-early table variety Bintje and the two early-main crisping varieties Maritta and Saturna were used. Three chitting periods (0, 6 and 12 weeks) and two planting dates (the beginning of April and May) were investigated. The change in crisping quality over a 7–8 month storage period was checked by frying tests at two to two-and-a-half monthly intervals. The criterion of quality was the colour of the crisps. Duration of chitting had little effect on crisping quality. The effect of planting date was strongly affected by the weather in a given year. In most years, but not for the experiment overall, the colour rating of the chips was slightly but significantly better for the later rather than the earlier planting date. The two crisping varieties Maritta and Saturna reached optimum suitability for crisping about twothirds of the way through the storage period, i.e. about March, the late plantings showing a more marked improvement in quality than the early ones (Table 1, Fig. 1–4). The weather, sometimes in combination with various soil conditions, had the greatest influence on the experimental results. This is concluded since the effects of the individual experimental factors depend on the season (Fig. 1–4) and from the difference in the averaged yearly results. Statistical analysis showed highly significant years and all experimental factors but chitting. 1976 merits special attention due to the extremely warm and dry summer weather. Potatoes which at the start of storage were generally poor showed a great improvement in quality during storage, especially those from the later planting. From the results it is obvious that the producer of quality potatoes for industry faces difficulties in choosing growing methods for improving quality due to the unpredictability of the consequences of weather conditions.
    Kurzfassung: Résumé L'influence de la durée de prégermination des plants et de la date de plantation sur l'aptitude des pommes de terre à la fabrication de pommes chips a été examinée dans un essai répété pendant 5 ans. Les cultivars ci-après ont été examinées: Bintje, variété mi-précoce de consommation, Maritta et Saturna, variétés mi-tardives présentant une très bonne aptitude à la fabrication de pommes chips. Trois procédés de prégermination (0, 6 et 12 semaines) ainsi que deux dates de plantations (début avril et début mai) ont été comparés. L'évolution de la qualité des chips au cours d'une durée de conservation de 7 à 8 mois, a été contrôlée à intervalles de deux mois à deux mois et demi, par des tests de fabrication. La couleur des pommes chips a constitué le critère de qualité. La prégermination n'a pratiquement pas influencé la qualité des chips. L'effet de la date de plantation était en relation étroite avec les conditions météorologiques de l'année. Sur un grand nombre d'années d'essais et compte tenu des exceptions, une amélioration peu importante mais néanmoins significantive de la qualité des chips, a été obtenue par la plantation tardive, par rapport à la plantation précoce. Pour les variétés spécifiquement aptes à la fabrication de chips, Maritta et Saturna, les tubercules ont atteint leur qualité optimale aux deux tiers de la durée de conservation, soit en mars environ. L'amélioration de la qualité a été plus prononcée pour les tubercules issus de la plantation tardive que pour ceux de la plantation précoce (tableau 1, fig. 1–4). Ce sont les conditions de croissance et les différences de structure du sol qui ont influencé le plus les résultats de ces essais. L'effet de l'année sur les paramètres examinés a été évident (fig. 2–4). L'analyse statistique (tableau 1) donne une interaction hautement significative entre les années et les paramètres d'essais, exception faite de la prégermination. Les résultats de l'année 1976 méritent une attention particulière, en raison des températures élevées, de la sécheresse durant l'été. La qualité des tubercules a été plutôt médiocre en début de conservation. Par la suite, plusieurs lots, et particulièrement ceux de la plantation tardive, se sont fortement améliorés (fig. 3). Ces résultats démontrent pour la production de pommes de terre destinées à la transformation industrielle, les difficultés auxquelles se heurte le choix des techniques culturales appropriées, en raison des conditions météorologiques imprévisibles.
    Notizen: Zusammenfassung Die in einem mehrjährigen Versuch (1973–1977) mit den Sorten Bintje, Maritta und Saturna geprüften Faktoren Vorkeimen und Pflanzzeitpunkt des Saatgutes sowie Lagerdauer des Erntegutes, übten folgende Einflüsse auf die Farbe von daraus hergestellten Pommes Chips aus: - Spätes Pflanzen (anfangs Mai) brachte in der Mehrzahl der Versuchsjahre eine leichte Verbesserung der Chipsfarbe bei jeweils mindestens zwei der drei Versuchssorten gegenüber frühem Pflanzen (anfangs April). - Die Vorkeimdauer hatte keinen Einfluss. - Mit zunehmender Lagerdauer trat mindestens bis zum Monat März bei den beiden Chips-Sorten Maritta und Saturna eine Qualitätsverbesserung ein, die bei den spätgepflanzten Varianten etwas deutlicher ausfiel als bei den frühgepflanzten. Die Ergebnisse wurden durch die Jahreswitterung und teils auch durch die Bodenbeschaffenheit stark beeinflusst.
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  • 2
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    Unbekannt
    In:  Landwirtschaftl. Jahrbuch 64:241-296
    Publikationsdatum: 1926
    Beschreibung: Zusammenhang zwischen Niederschlag, Temperatur und Erträgen. Untersucht wurden Winterweizen, Winterroggen, Sommergerste, Sommerroggen, Kartoffeln, Futterpflanzen und Wiesen KATASTER-BESCHREIBUNG: Einfluss der Witterungsfaktoren Niederschlag und Temperatur auf die Ernteerträge KATASTER-DETAIL: Delta Nied +, dann Erträge (Halmfrüchte und Kartoffeln) + und später -; Delta T -, dann Erträge +,
    Schlagwort(e): Deutsches Reich (östl. u. westl. Provinzen, Hannover, Sachsen, Rheinland) ; 1899-1913 ; Ertrag ; Getreide ; Rangordnungsmethode ; Witterung ; Hackfrüchte
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  • 3
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    Unbekannt
    In:  Diss.; Freiburg
    Publikationsdatum: 1926
    Beschreibung: Abhängigkeit der Getreideerträge von Witterungseinflüssen mithilfe der Korrelationsmethode in 11 orographisch abgegrenzen Gebieten KATASTER-BESCHREIBUNG: Korrelation zwischen der Abweichung vom 11, bzw. 30jährigen monatlichen Mittel (April-Juli) der Niederschläge und dem Ertrag von Getreidearten (Weizen, Dinkel, Roggen, Gerste, Hafer) KATASTER-DETAIL: Nied 〉 (11, bzw. 30jährigen monatlichen Mittel von 1888-1898 und 1888-1917 im Monat Mai, je nach Region 55-158mm), dann höchste Übereinstimmung der Korrelationskoeffienten für die Ertragszunahme über alle Kulturen
    Schlagwort(e): Baden ; 1888-1898 und 1888-1917 ; Ertrag ; Getreide ; Korrelationsmethode ; Niederschlag ; Temperatur ; Witterung
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  • 4
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    Unbekannt
    In:  Vereinigten Friedrichs-Universität Halle-Wittenberg, Halle.
    Publikationsdatum: 1928
    Beschreibung: Ertragsrelevante Korrelationen bei Winterweizen und -gerste mit der Temperatur, bei allen übrigen Kulturen war Niederschlag entscheidend KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Saalkreis, Kreis Bitterfeld, Kreis Delitzsch, Kreis Wittenberg, südl. Teil Kreis Köthen ; 1900-26 ; Kartoffeln ; Boden ; Ertrag ; Getreide ; Hafer ; Niederschlag ; Rangordnungsmethode ; Roggen ; Temperatur ; Weizen ; Witterung ; Hackfrüchte
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  • 5
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    Unbekannt
    In:  Diss. Hohenheimm
    Publikationsdatum: 1929
    Beschreibung: Ergebnisse (Rangordungs- und Korrelationsmethode) der Beziehung zwischen Witterung und Ertrag vieler Kulturen eingeteilt nach Monaten KATASTER-BESCHREIBUNG: Einfluss der Temperatur und des Niederschlags auf den Ertrag folgender Kulturpflanzen: Winterweizen, Winterroggen, Dinkel, Sommerweizen, Sommerroggen, Sommergerste, Hafer, Hopfen, Luzerne, Rotklee, Wiesen, Kartoffeln) KATASTER-DETAIL: Delta T (Vegetationszeit) -, dann Ertrag (Winter- und Sommergetreide) +; Delta T (Winter, Juni und Juli) -, dann Ertrag (Sommergetreide) +; Delta Nied (Winter) +, dann Ertrag (Getreide) -; Delta T (September) - und Delta Nied (Vegetationszeit) +, dann Ertrag (Futterpflanzen) +; Details für einzelne Kulturpflanzen: siehe Artikel
    Schlagwort(e): Württemberg ; 1899-1913 ; Ertrag ; Hafer ; Korrelationsmethode ; Niederschlag ; Rangordnungsmethode ; Temperatur ; Weizen ; Witterung
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  • 6
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    Unbekannt
    In:  Berichte des Deutschen Wetterdienstes, Nr. 92, Band 13,
    Publikationsdatum: 1964
    Beschreibung: Beurteilung des großräumigen Witterungsablaufs und Überprüfung der alten Temperaturwerte KATASTER-BESCHREIBUNG: - KATASTER-DETAIL: -
    Schlagwort(e): Deutschland ; 1708-1709 ; Temperatur ; Witterung
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  • 7
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    Unbekannt
    In:  Die Gartenbauwissenschaft 2: 459-539
    Publikationsdatum: 1929
    Beschreibung: Einfluss der Witterung ist Gattungs- teils sortenabhängig, und wechselt mit der Lage der Orte. Trockenheit im Vorjahr begünstigt die Ernteerträge, KATASTER-BESCHREIBUNG: Trockenheit im Vorjahr begünstigt verbunden mit hoher Temperatur, geringer Luftfeuchtigkeit und langer Sönnenscheindauer, mit niedriger Temperatur, hoher Luftfeuchte, kurzer Sonnenscheindauer im Erntejahr, wirkt positiv auf die Ernteerträge für bestimmte Apfel - und Birnensorten, umgekehrte Beziehung insbesondere bei Früh-, Herbst- und Winterbirnensorten KATASTER-DETAIL:
    Schlagwort(e): Niedersachsen ; 1900-1923 ; Apfel ; Ertrag ; Trockenheit ; Witterung ; Obst ; Birne
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  • 8
    Publikationsdatum: 1929
    Beschreibung: vgl. Neustädt KATASTER-BESCHREIBUNG: Zusammenhang Witterungsfaktoren in wachstumsrelevanten Zeitspannen mit dem Ertrag verschiedener Kulturen KATASTER-DETAIL: Delta Nied (Oktober bis März) -, dann Erträge (Roggen) +; Delta Nied (Januar) -, dann Erträge (Roggen) ++; Delta Nied (Februar) +, dann Erträge (Roggen) +; Delta Nied (Mai) +, dann Erträge (Roggen) +; Delta Nied (Mai) 〉 1,5x Mittel, dann Erträge -; Delta Sonn (Mai, im Bezirk Köthen) +, dann Erträge (Roggen) -; Delta Nied (Januar, März, April) -, dann Erträge (Sommergerste) +; Delta Nied (Februar, Mai bis Ernte) +, dann Erträge (Sommergerste) +; Delta Nied (Mai) +, dann Erträge (Sommergerste) ++; (Informationen zu den weiteren landwirtschaftlicher Kulturpflanzen: siehe Artikel)
    Schlagwort(e): Mitteldeutschland ; 1900-1926 ; Kartoffeln ; Ertrag ; Niederschlag ; Roggen ; Temperatur ; Witterung ; Hackfrüchte
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  • 9
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    Unbekannt
    In:  Archiv für Landwirtschaft, A.3: 471-555
    Publikationsdatum: 1929
    Beschreibung: Einfluß der Witterung auf die Qualität von Weizen KATASTER-BESCHREIBUNG: Witterungsverhältnisse der letzten 5 bis höchstens 10 Tage vor der Gelbreife sind von entscheidendem Einfluss, Backqualität nimmt von kontinentalem zum maritimen Klima ab KATASTER-DETAIL: Tmit+, Sonn+, Nied-, dann gute Qualität Nied+, dann Tausendkorngewicht + aber Nied**, dann Tausendkorngewicht - und N-Gehalt +
    Schlagwort(e): Mitteldeutschland ; 1900-1925 ; Ertrag ; Korrelationsmethode ; Landwirtschaft ; Niederschlag ; Temperatur ; Trockenheit ; Weizen ; Witterung ; Sonnenscheindauer
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  • 10
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    In:  Kühn-Archiv, Berlin, Band XX, Seite 223-301
    Publikationsdatum: 1928
    Beschreibung: Auswertung von 27 Versuchsjahren, Bestimmung einer kritischen Periode für die Mindestniederschlagshöhe durch Auswertung der Klimaparmeter in einzelnen Bezirken mittels Rangkorrelationskoeffizienten KATASTER-BESCHREIBUNG: Zusammenhang zwischen der Niederschlagshöhe und dem Ertrag von Zuckerrüben, Zusammenhang zwischen der Sonnenscheindauer und dem Zuckergehalt von Zuckerrüben KATASTER-DETAIL: Delta Nied+: Nied 〉 175 mm (Juli-September), dann Ertragssteigerung bei ZR; Delta Sonn +: Sonn〉 4.43 h (September -Oktober), dann hohe Zuckergehalte bei ZR
    Schlagwort(e): Sachsen-Anhalt ; 1900-1926 ; Zuckerrüben ; Niederschlag ; Rangordnungsmethode ; Temperatur ; Witterung
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  • 11
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    Unbekannt
    In:  Landw. Jahrbuch 68:537-558
    Publikationsdatum: 1929
    Beschreibung: Untersuchungen der Beziehungen zwischen Pferdebohne (Vicia faba L.) und der Witterung. Einteilung des Wachstums in Abschnitte KATASTER-BESCHREIBUNG: Einfluss der Witterung auf die Entwicklung und den Ertrag der Pferdebohne KATASTER-DETAIL: Delta T + und Delta Sonn +, dann Reife + (früher); Delta T +, dann 1. Wachstumsabschnitt (vom Auflaufen bis zum Blütebeginnn) - (kürzer); Delta T + und Delta Sonn +, dann 3. Wachstumsabschnitt (Reifezeit) - (kürzer); Delta T +, dann Gesamtwachstumszeit +; Delta Nied +, dann Gesamtwachstumszeit -; Delta T (Gesamtwachstumszeit,Jugendzeit) +, dann Kornzahl +; Delta Sonn (Blütezeit) +, dann Kornzahl +; Delta Nied +, dann Kornzahl -; Delta T (Reifezeit) - und Delta Nied (Reifezeit) +, dann Pilzbefall + und somit Kornzahl -; Delta T +, dann Kornschwere -; Delta Nied (10 Tage vor bis 10 Tage nach Blütenende) +, dann Kornschwere +; Delta T +, dann Hülsenzahl +; Delta Nied +, dann Hülsenzahl -; Delta Nied (alle Wachstumszeiten) + und Delta T (bis zum Blütenende) + und Delta Sonn -, dann Strohgewicht +;
    Schlagwort(e): Freising, Bayern ; 1921-1926 ; Ertrag ; Witterung ; Gemüse
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  • 12
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    In:  Deut. Landwirtschaflt. Presse 55:94-95.
    Publikationsdatum: 1928
    Beschreibung: Übersicht über die Literatur zum Einfluss des Wetters auf die Kulturpflanzen KATASTER-BESCHREIBUNG: Milder und trockener Winter wirkt positiv auf die Weizenerträge, kalter und niederschlagsreicher Winter eher negativ, Betrachung für Norddeutschland KATASTER-DETAIL:
    Schlagwort(e): Deutschland ; 1900-1926 ; Kartoffeln ; Ertrag ; Getreide ; Hafer ; Landwirtschaft ; Niederschlag ; Roggen ; Temperatur ; Trockenheit ; Witterung ; Gerste
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  • 13
    Publikationsdatum: 1929
    Beschreibung: Einfluss der Witterungsfaktoren auf verschiedene Kulturen und die Betriebssysteme KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Deutschland ; Witterung
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  • 14
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    In:  Zeitschrift für Acker- und Pflanzenbau 112:399-412.
    Publikationsdatum: 1961
    Beschreibung: Anwendung der Wetterwertzahlmethode nach Tamm und Vereinfachung, Einfluss von Lufttemperatur, Bodentemperatur, Niederschlag, Luftfeuchte, Verdunstung und Sonnenscheindauer auf den Ertrag, Zusamenhang zwischen Bodenfeuchte und Wetterwertzahl (Potsdam und Berlin) KATASTER-BESCHREIBUNG: Wetterwertzahlenmethode ist auch für einzelne Feldbestände anwendbar; Vereinfachte Wetterwertzahl beruht auf tatsächlich ermittelten Messwerten; Bodenfeuchtigkeit und vereinfachte Wetterwertzahlen stehen miteinander in enger Beziehung (starke Korrelation) KATASTER-DETAIL: Wetterwertzahl -, dann Bodenfeuchte + (starke Korrelation)
    Schlagwort(e): Berlin-Dahlem ; 1955-57 ; Ertrag ; Niederschlag ; Temperatur ; Witterung ; Sonnenscheindauer
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  • 15
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    In:  Zeitschrift für Pflanzenernährung, Düngung, Bodenkunde 6:490-496.
    Publikationsdatum: 1927
    Beschreibung: Einfluss der Witterungsfaktoren Niederschlag, Temperatur und Sonnenscheindauer auf die Erträge KATASTER-BESCHREIBUNG: Einteilung der Temperatur in Klassen (stark, mittel, gering) und die Beurteilung auf die Erträge in den 6 Provinzen des deutschen Reiches, mit Vermehrung der Niederschlage wahrend der Vegetationszeit Zunahme der Halmfrüchte und der Kartoffeln im gröBten Teile des PreuBischen Staates anfangs, jedoch nd spater wieder abnehmender Trend KATASTER-DETAIL: Delta T+ (April-Augut), dann Winterweizenerträge + in OstpreuBen, Brandenburg und Sachsen Delte T++ (April-August), dann Winterweizenerträge ++ in Ostpreußen, aber - in Brandenburg und Sachsen Delta T- (April-Augut), dann Winterweizenerträge - in Hannover und der Rheinprovinz Delta T+ (+0.1° Erhöhung Temperaturmittel der Monate April bis September), dann Kartoffel+ in OstpreuBen und Schlesien
    Schlagwort(e): Deutschland, teilw. einzelne Regionen ; 1899-1913 ; Ertrag ; Niederschlag ; Temperatur ; Witterung ; Sonnenscheindauer
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  • 16
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    Unbekannt
    In:  Schweiz Z. Obst- und Weinbau 72: 32-34
    Publikationsdatum: 1963
    Beschreibung: Beobachtungen zu den Auswirkungen verschiedener Witterungen auf den Ertrag und die Qualität der Weinernte KATASTER-BESCHREIBUNG: Einfluss der Witterung (Sonnenschein, Niederschlag und Temperatur) auf den Ertrag und die Qualität der Weinernte KATASTER-DETAIL: Delta Nied +, dann Pilzkrankheiten + und somit Ertrag (Wein)-; Delta T (Sommer und Herbst) + und Delta Nied (Sommer und Herbst) -, dann Qualität (Wein) +; Delta Sonn (August, September) +, dann Qualität (Wein) +; Delta T (April bis Juli) -, dann Entwicklung (Reben) -;
    Schlagwort(e): Schweiz ; 1953-1962 ; Niederschlag ; Temperatur ; Wachstum ; Witterung ; Sonnenscheindauer ; Wein
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  • 17
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    Unbekannt
    In:  Die Kartoffel, S. 66
    Publikationsdatum: 1926
    Beschreibung: Zusammenhang zwischen der Witterung und der Stärkeeinlagerung bei Kartoffeln KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Kartoffeln ; Ertrag ; Witterung
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  • 18
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    Unbekannt
    In:  Mitt. DLG, S. 128
    Publikationsdatum: 1928
    Beschreibung: Zusammenhang zwischen der Witterung und den Knollenerträgen KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Kartoffeln ; Ertrag ; Witterung
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  • 19
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    Unbekannt
    In:  Zeitschr. Pflanzenbau 2.
    Publikationsdatum: 1925
    Beschreibung: Zusammenhang Witterung und Knollenansatz und -gewicht bei Kartoffeln KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Kartoffeln ; Ertrag ; Witterung
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  • 20
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    In:  Kühn-Archiv 20:140-222.
    Publikationsdatum: 1929
    Beschreibung: Untersuchungen an Ernteergebnissen mittels Rangordnungs- und Korrelationsmethode zur Abhängigkeit von den Witterungsfaktoren. Untersucht wurden die Erträge von Weizen, Roggen, Sommergerste, Hafer, Erbsen und Zuckerrüben KATASTER-BESCHREIBUNG: Einfluss der Witterung (Temperatur, Niederschlag, Sonnenscheindauer) auf die Erträge der Kurlturpflanzen KATASTER-DETAIL: Delta T (Oktober, November) - und Delta T (Januar, Februar) +, dann Erträge (Weizen) +; Delta Nied (April, Mai) + und Delta Nied (Februar, März) -, dann Erträge (Weizen) +; Delta Sonn (März) +, dann Erträge (Weizen) +; Delta Nied (Mai - Zeit des Schossens) +, dann Erträge (Roggen) +; Delta T (November) -, dann Erträge (Roggen) +; Delta Nied (April, Juni) + und Delta T (April, Juni) -, dann Erträge (Sommergerste) +; Nied (April, Juni) 〉 180mm, dann Erträge (Sommergerste) -; Delta Sonn (März, April) + und Delta Sonn (Mai) -, dann Erträge (Sommergerste) +; Delta Nied (April bis Juni) +, dann Erträge (Hafer) +; Delta Sonn (März, April) +, dann Erträge (Hafer) +; Delta T (Juni) -, dann Erträge (Hafer) +; Delta Nied (Juni, September) +, dann Erträge (Zuckerrübe) +; Delta Nied (August) +, Zuckergehalt +; Delta T (Juni) +, dann Erträge (Zuckerrübe) +; Delta Sonn (September) +, Qualität der Ernte +; Delta Sonn (März, April) + und Delta Sonn (Mai, Juni) -, dann Erträge (Getreide) +;
    Schlagwort(e): Mansfelder See- und Saalkreis, Kreis Querfurt, Kreis Merseburg ; 1900-1925 ; Zuckerrüben ; Hafer ; Niederschlag ; Roggen ; Temperatur ; Weizen ; Witterung ; Sonnenscheindauer ; Gerste ; Erbsen
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  • 21
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    In:  Nachrichtenblatt für den deutschen Pflanzenschutzdienst, Jahrgang 15 (neue Folge), Heft 8, p. 161-175
    Publikationsdatum: 1961
    Beschreibung: Untersuchungen zur Biologie der Rübsenblattwespe mit Beobachtungen zum Einfluss der Witterung auf die Entwicklung KATASTER-BESCHREIBUNG: Zusammenhang zwischen Temperatur und den verschiedenen Entwicklungsphasen der Wespe KATASTER-DETAIL: Delta T: Delta T + (bis T=21°C), dann Entwicklungsgeschwindigkeit der Embryonen +; T〉30°C, dann Abbruch der Embryonalentwicklung; Delta T + (bis T=30°C, dann Entwicklungsgeschwindigkeit der Larven +; T〉30°C, dann Abbruch der Larvenentwicklung; Delta T: 18°C〈T〈20°C, dann größte Eizahl; T〉20°C, dann Eizahl -; Delta T +, dann Zeitpunkt der Eiablage früher; Delta T + und Delta Nied -, dann Massenvermehrung;
    Schlagwort(e): Thüringen ; 1955-1960 ; Pflanzenschädling ; Temperatur ; Witterung ; Senf
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  • 22
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    Unbekannt
    In:  Der Kartoffelbau, Nr. 69
    Publikationsdatum: 1925
    Beschreibung: Zusammenhang der Witterungselemente, insbesondere der Sommerniederschläge zum Ertrag bei Kartoffeln KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Breslau ; 1901-1921 ; Kartoffeln ; Ertrag ; Witterung
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    facet.materialart.
    Unbekannt
    In:  Zeitschrift für Pflanzenernährung, Düngung, Bodenkunde 95:1-9
    Publikationsdatum: 1961
    Beschreibung: Witterung, insb. Niederschlag als Einflußgröße für Erträge, Auswertung von N- und P-Mangelversuchen KATASTER-BESCHREIBUNG: Einfluss der Witterung (Niederschlag) auf die Erträge bei Nährstoffmangel (P, K, N) KATASTER-DETAIL: Delta Nied -, dann P-Mangel + und Kali-Mangel +; Delta Nied +, dann Erträge (Weizen und Hafer) -; Delta Nied (Winter) +/-: Nied (Durchschnitt)= 399 mm, dann Ertrag bei N-Mangel + Nied (Durchschnitt)= 267 mm, dann Ertrag bei N-Mangel + Nied (Durchschnitt)= 327 mm, dann Ertrag bei N-Mangel -
    Schlagwort(e): Kölner Bucht ; 1906–1957 ; Ertrag ; Getreide ; Niederschlag ; Temperatur ; Witterung ; Düngung
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    facet.materialart.
    Unbekannt
    In:  Kühn-Archiv:53-78.
    Publikationsdatum: 1925
    Beschreibung: Einführung der Rangordnungs- und Korrelationsmethode anhand langjähriger Beobachtungen, Einfluss des Niederschlages und der Temperatur auf den Ertrag von Erbsen, Kartoffeln, Weizen, Hafer und Roggen KATASTER-BESCHREIBUNG: Einfluss der Witterung (Temperatur und Niederschlag) auf den Ertrag KATASTER-DETAIL: Delta T (März und April) + und Delta Nied (März und April) -, dann Erträge (Erbsen) +; Delta T (Mai und Juni) - und Delta Nied (Mai und Juni) +, dann Erträge (Erbse) +; Delta T (Oktober Vorjahr) +, dann Erträge (Kartoffel) +; Delta T (März) + und Delta T (Mai und Juni) -, dann Erträge (Winterweizen) +; Delta Nied (Januar bis März)-, dann Erträge (Hafer) +; Delta Nied (Januar bis März)-, dann Erträge (Winterroggen) +;
    Schlagwort(e): Halle ; 1893-25 ; Kartoffeln ; Ertrag ; Fichte ; Hafer ; Korrelationsmethode ; Niederschlag ; Rangordnungsmethode ; Roggen ; Temperatur ; Weizen ; Witterung
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    facet.materialart.
    Unbekannt
    In:  Diss., Göttingen
    Publikationsdatum: 1925
    Beschreibung: Ergebnisse ( Korrelationsmethode) der Bezeihung zwischen Witterung und Ertrag vieler Kulturen eingeteilt nach Monaten KATASTER-BESCHREIBUNG: Beziehungen zwischen Witterung (Temperatur und Niederschlag)und Ernte KATASTER-DETAIL: Delta Nied (erste 10 Blütetage) -, dann Ertrag (Roggen) +; Delta Nied (Beginn der Blüte bis 10 tage nach Ende der Blüte)-, dann Ertrag (Winterweizen) +; Delta Nied (während der 20 Tage nach Beginn der Blüte) -, dann Ertrag (Sommerweizen) +; Delta Tmit (während der 20 Tage nach dem Aufgang) -, dann Ertrag (Hafer) +; Delta Tmin (während der 20 Tage nach dem Aufgang) -, dann Ertrag (Gerste) +; Delta Tmit (während der 20 Tage nach Beginn der Blüte) -, dann Ertrag (Kartoffeln) +; Delta Nied (vom Aufgang bis zum Beginn der Blüte) -, dann Ertrag (Erbsen) +; Delta Nied +, dann Ertrag (Vietsbohnen) +;
    Schlagwort(e): Göttingen ; 1901-1922 ; Kartoffeln ; Ertrag ; Hafer ; Korrelationsmethode ; Niederschlag ; Temperatur ; Weizen ; Witterung ; Erbsen
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
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    Unbekannt
    In:  Landw. Wochenschrift für die Provinz Sachsen und Anhalt, Hallle 18:428ff.
    Publikationsdatum: 1928
    Beschreibung: Zusammenhang Witterung in Monaten und Gerstenertrag KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Sachsen und Anhalt ; 1920 ; Ertrag ; Getreide ; Landwirtschaft ; Niederschlag ; Temperatur ; Witterung
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
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    Unbekannt
    In:  Diss., Hohenheim.
    Publikationsdatum: 1928
    Beschreibung: Beziehung zwischen Witterung (unterteilt in einzelne Monate) und Ertragshöhe mithilfe der Rangordnungs- und der Korrelationsmethode KATASTER-BESCHREIBUNG: Einfluss der Witterung (Temperatur, Niederschlag, Sonnenscheindauer) auf den Ertrag von Winterweizen, Sommerweizen, Sommergerste, Wintergerste, Hafer und Runkelrüben auf dem Versuchsfeld (wasserundurchlässiger Boden) KATASTER-DETAIL: Delta Sonn (Oktober bis November)+, dann Erträge (Winterweizen) +; Delta Sonn (Dezember bis März)+, dann Erträge (Winterweizen) -; Delta Sonn (April) -, dann Erträge (Winterweizen) +; Delta Nied (April) +, dann Erträge (Winterweizen) +; Delta Nied (Mai, Juni und Juli) -, dann Erträge (Winterweizen) +; Delta Nied (August bis Oktober) +, dann Erträge (Winterweizen) +; Delta T (April) -, dann Erträge (Winterweizen) +; (Details sowie Informationen für Sommerweizen, Sommergerste, Wintergerste, Hafer und Runkelrüben siehe Artikel)
    Schlagwort(e): Hohenheim (Baden-Württemberg) ; 1914-25 ; Ertrag ; Getreide ; Hafer ; Klima ; Korrelationsmethode ; Niederschlag ; Rangordnungsmethode ; Temperatur ; Weizen ; Witterung ; Hackfrüchte
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
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    Unbekannt
    In:  Zeitschrift für Pflanzenernährung, Düngung, Bodenkunde 16.
    Publikationsdatum: 1926
    Beschreibung: Beziehungen zwischen Witterung und Ernteertrag KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Hohenheim (Baden-Württemberg) ; 1914-25 ; Ertrag ; Witterung
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
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    Unbekannt
    In:  Landw. Jahrbuch Berlin 63(1):1-81
    Publikationsdatum: 1926
    Beschreibung: Auszug aus der Diss. KATASTER-BESCHREIBUNG: Beziehungen zwischen Witterung (Temperatur und Niederschlag)und Ernte KATASTER-DETAIL:
    Schlagwort(e): Göttingen ; 1901-1922 ; Ertrag ; Korrelationsmethode ; Niederschlag ; Temperatur ; Witterung ; Hackfrüchte ; Erbsen
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
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    Unbekannt
    In:  Zeitschrift für Acker- und Pflanzenbau 3:330-334.
    Publikationsdatum: 1926
    Beschreibung: Angabe von Niederschlagsmengen und Durchschnittstemperaturen für das ökologische Optimum bestimmter Sorten, kritische Zeiten (vor und nach der Blüte) sind hierfür entscheidend KATASTER-BESCHREIBUNG: Einfluss von Wasser und Wärme, bzw. Niederschlag und Temperatur auf den Ertrag KATASTER-DETAIL: Roggen, Weizen: Delta Nied (Beginn Blütezeit)-, dann Ertrag +; Hafer, Gerste, Kartoffel: Delta T (Beginn der Blüte) -, dann Ertrag +; Bohne: Delta T (gesamte Wachstumszeit)+ und Delta Nied (gesamte Wachstumszeit) +, dann Ertrag +
    Schlagwort(e): Göttingen ; 1901-22 ; Kartoffeln ; Ertrag ; Getreide ; Hafer ; Klima ; Korrelationsmethode ; Niederschlag ; Roggen ; Temperatur ; Weizen ; Witterung ; Hackfrüchte ; Erbsen
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    facet.materialart.
    Unbekannt
    In:  Trudy vscsojuzn nauen. met. soversi. 8 (russ.)
    Publikationsdatum: 1963
    Beschreibung: Bedeutung der Winterfeuchte für die Ertragsbildung in Regionen mit Sommertrockenheit KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Russland ; Wende vom 18. zum 19. Jahrundert ; Getreide ; Landwirtschaft ; Niederschlag ; Trockenheit ; Witterung
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    facet.materialart.
    Unbekannt
    In:  Intern. Agrik.-Wiss. Rundsch. N.F. 1;p.406-424
    Publikationsdatum: 1925
    Beschreibung: Der Autor fasst in einer Literaturstudie Forschungsergebnisse und -erkenntnisse von Studien zum Zusammenhang zwischen klimatischen Parametern und dem Auftreten verschiedener Pflanzenkrankheiten aus Feldversuchen zusammen und vergleicht diese mit eigenen Beobachtungen aus Indien. Aus dem Literaturstudium gewonnene Kardinalwerte für verschiedene Pflanzenkrankheiten sind enthalten. Schwerpunkte der Sammlung an Erkenntnissen stellen Indien und die USA dar. KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Schlagwort(e): Indien, USA, Welt ; 1900-1925 ; Pflanzenkrankheit ; Witterung
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    facet.materialart.
    Unbekannt
    In:  Kühn-Archiv, Berlin, XX, Seite 7-129
    Publikationsdatum: 1929
    Beschreibung: Lage der Hochs nördlich und südlich des 50. Breitengrades und ihre Bedeutung für die Witterung und Ernteerträge in Mitteldeutschland KATASTER-BESCHREIBUNG: KATASTER-DETAIL: Tmit+ (Janurar, Februar, März, Mai und Dezember) durch Abnahem der barometrischen Nordlagen Tmit- (August, September) durch Zunahme der barometrischen Nordlagen Nied+ (Janurar, Apri,, Mai, August, September, Dezember) durch Abnahmen der barometrischen Nordlagen (entspricht Zunahmen der Südlagen!) Nied- (Februar, März, Oktober und November) durch Abnahmen der barometrischen Nordlagen (entspricht Zunahmen der Südlagen!)
    Schlagwort(e): Deutschland ; 1900-1925 ; Luftfeuchte ; Ertrag ; Getreide ; Landwirtschaft ; Niederschlag ; Temperatur ; Trockenheit ; Witterung ; Sonnenscheindauer
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    facet.materialart.
    Unbekannt
    In:  Georgine, Jahrgang 102, Nr. 68, p. 806-807
    Publikationsdatum: 1925
    Beschreibung: Biologie und Bekämpfung von Fritfliege, Getreideblumenfliege, scheckige oder gelbe Halmfliege, Weizenfliege, Hessenfliege KATASTER-BESCHREIBUNG: Einfluss der Witterung (Temperatur, Niederschlag und Wind) auf die Schädlinge KATASTER-DETAIL: Delta T (Winter) +, Anzahl Maden der Halmfliege +; Delta Nied (September) + und Delta Wind (September) +, dann Hessenfliege -
    Schlagwort(e): Deutschland ; 1903-1925 ; Insekten ; Anbautermine ; Boden ; Ertrag ; Getreide ; Hafer ; Niederschlag ; Pflanzenschädling ; Temperatur ; Vegetationsperiode ; Weizen ; Wind ; Witterung ; Düngung ; Gerste
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    Publikationsdatum: 2004-12-03
    Beschreibung: The development of an integrated approach to the modeling of forest dynamics encompassing submodels of forest growth and succession, soil processes and radiation interactions, is reported. Remote sensing technology is a key element of this study in that it provides data for developing, initializing, updating, and validating the models. The objectives are reviewed, the data collected and models in use are discussed, and a framework for studying interactions between the forest growth, soil process and energy interaction components, is described. Remote sensing technology used in the study includes optical and microwave field, aircraft and satellite borne instruments. The types of data collected during intensive field and aircraft campaigns included bidirectional reflectance, thermal emittance and multifrequency, multipolarization synthetic aperture radar backscatter. Synthetic imagery of derived products such as forest biomass and NDVI (Normalized Difference Vegetative Index), and collections of ground data are being assembled in a georeferenced data base. These data are used to drive or test multidiscipline simulations of forested ecosystems. Enhancements to the modeling environment permit considerable flexibility in configuring simulations and selecting results for reporting and graphical display.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 1005-1012
    Format: text
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  • 36
    Publikationsdatum: 2004-12-03
    Beschreibung: The quantitative interpretation of satellite observations requires the use of mathematical tools to extract the desired information on terrestrial environments from the radiation data collected in space. A whole range of approaches can be pursued, from the development of models capable of explaining the nature of the physical signal being measured and of characterizing the state of the system under observation, to the empirical correlations between the variables of interest and the space measurements. The premises and implications of these approaches are outlined, paying special attention to the mathematical and numerical requirements. The role and specific applications of empirical bidirectional reflectance models is also discussed, even though these models do not contribute to the understanding of the theory of radiation transfer or to the assessment of the variables of interest. The advantages and drawbacks of these various approaches and the research priorities for the next few years are discussed in the context of the planned availability of new sensors.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 993-1004
    Format: text
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  • 37
    Publikationsdatum: 2004-12-03
    Beschreibung: Management of crop residues, the portion of a crop left in the field after harvest, is an important conservation practice for minimizing soil erosion and for improving water quality. Quantification of crop residue cover is required to evaluate the effectiveness of conservation tillage practices. Methods are needed to quantify residue cover that are rapid, accurate, and objective. The fluorescence of crop residue was found to be a broadband phenomenon with emission maxima at 420 to 495 nm for excitations of 350 to 420 nm. Soils had low intensity broadband emissions over the 400 to 690 nm region for excitations of 300 to 600 nm. The range of relative fluorescence intensities for the crop residues was much greater than the fluorescence observed of the soils. As the crop residues decompose their blue fluorescence values approach the fluorescence of the soil. Fluorescence techniques are concluded to be less ambiguous and better suited for discriminating crop residues and soils than reflectance methods. If properly implemented, fluorescence techniques can be used to quantify, not only crop residue cover, but also photosynthetic efficiency in the field.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 855-862
    Format: text
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  • 38
    Publikationsdatum: 2004-12-03
    Beschreibung: The importance of the measurement of wind fields is discussed. Wind regime data can be used to infer the amount and type of wind induced (aerolian) transport of sand and dust, or to establish global circulation models, for example on other planets. Since local measurements are costly and often impossible, it is desired to infer such data from remotely sensed information. A potential mechanism for remotely inferring the wind regime by using synthetic aperture radar data to describe the roughness of the surface is described. A project to estimate the practicality of using such a mechanism is described. An experiment that extends the mechanism to vegetated sites, where the goal is to measure potential for erosion, is reported.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 451-456
    Format: text
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  • 39
    Publikationsdatum: 2004-12-03
    Beschreibung: Surface reflectance is required to quantitatively investigate molecular absorption and particle scattering properties of materials on the Earth's surface. Atmospheric aerosol optical depth, surface pressure and water vapor are required to constrain a radiative transfer code for the inversion of measured spectral radiance to apparent surface reflectance. A suite of algorithms using nonlinear least squares fitting techniques are described that directly estimate these atmospheric parameters from spectral radiance measured by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). The derived atmospheric parameters are used to constrain a radiative transfer code for the inversion of the imaging spectrometer radiance to apparent reflectance. The derived apparent reflectance is validated with respect to in situ measurement on the same target.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 193-200
    Format: text
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  • 40
    Publikationsdatum: 2004-12-03
    Beschreibung: Investigations designed to study land surface hydrologic-atmospheric interactions, showing the potential of L band passive microwave radiometry for measuring surface soil moisture over large areas, are discussed. Satisfying the data needs of these investigations requires the ability to map large areas rapidly. With aircraft systems this means a need for more beam positions over a wider swath on each flightline. For satellite systems the essential problem is resolution. Both of these needs are currently being addressed through the development and verification of Electronically Scanned Thinned Array Radiometer (ESTAR) technology. The ESTAR L band radiometer was evaluated for soil moisture mapping applications in two studies. The first was conducted over the semiarid rangeland Walnut Gulch watershed located in south eastern Arizona (U.S.). The second was performed in the subhumid Little Washita watershed in south west Oklahoma (U.S.). Both tests showed that the ESTAR is capable of providing soil moisture with the same level of accuracy as existing systems.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 467-474
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  • 41
    Publikationsdatum: 2004-12-03
    Beschreibung: A weather resistant automatic scanning Sun photometer system is assessed and demonstrated as practical for measurements of aerosol concentrations and properties at remote sites. Interfaced with a transmitter using the Geostationary Data Collection System (GDCS), the data are processed in near real time. The processing allows a time dependence of the aerosols and water vapor and an ongoing assessment of the health and calibration of the instruments. The system's automatic data acquisition, transmission, and processing offer immediate application to atmospheric monitoring and modeling on a regional to global scale and validation of satellite retrievals. It is estimated that under normal circumstances the retrieved aerosol optical thickness has a network wide accuracy of +/- 0.02 from 340 nm to 1020 nm, water vapor +/- 0.2 cm and size distribution from 0.1 to 3 micrometers.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 75-83
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  • 42
    Publikationsdatum: 2004-12-03
    Beschreibung: As part of a global program to validate the ocean surface sensors on board ERS-1, a joint experiment on the Grand Banks of Newfoundland was carried out in Nov. 1991. The principal objective was to provide a field validation of ERS-1 Synthetic Aperture Radar (SAR) measurement of ocean surface structure. The NASA-P3 aircraft measurements made during this experiment provide independent measurements of the ocean surface along the validation swath. The Radar Ocean Wave Spectrometer (ROWS) is a radar sensor designed to measure direction of the long wave components using spectral analysis of the tilt induced radar backscatter modulation. This technique greatly differs from SAR and thus, provides a unique set of measurements for use in evaluating SAR performance. Also, an altimeter channel in the ROWS gives simultaneous information on the surface wave height and radar mean square slope parameter. The sets of geophysical parameters (wind speed, significant wave height, directional spectrum) are used to study the SAR's ability to accurately measure ocean gravity waves. The known distortion imposed on the true directional spectrum by the SAR imaging mechanism is discussed in light of the direct comparisons between ERS-1 SAR, airborne Canadian Center for Remote Sensing (CCRS) SAR, and ROWS spectra and the use of the nonlinear ocean SAR transform.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: ESA, Proceedings of 2nd ERS-1 Symposium on Space at the Service of Our Environment, Volume 2; p 1161-1164
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  • 43
    Publikationsdatum: 2004-12-03
    Beschreibung: Terrain slopes, which can be measured with Synthetic Aperture Radar (SAR) interferometry either from a height map or from the interferometric phase gradient, were used to calculate the local incidence angle and the correct pixel area. Both are required for correct thematic interpretation of SAR data. The interferometric correlation depends on the pixel area projected on a plane perpendicular to the look vector and requires correction for slope effects. Methods for normalization of the backscatter and interferometric correlation for ERS-1 SAR are presented.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: ESA, Proceedings of 2nd ERS-1 Symposium on Space at the Service of Our Environment, Volume 2; p 723-726
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  • 44
    Publikationsdatum: 2004-12-03
    Beschreibung: The relationship between the gradient of the interferometric phase and the terrain slope, which, it is thought, would allow a derivation of the terrain slopes without phase unwrapping, is presented. A linear relationship between the interferometric phase gradient and the terrain slopes was found. A quantitative error analysis showed that only very small errors are introduced by these approximations for orbital Synthetic Aperture Radar (SAR) geometries. An example of a slope map for repeat pass interferometry from ERS-1 SAR data is given. A number of direct and indirect applications of the terrain slope are indicated: erosion and avalanche hazard studies, radiometric calibration of SAR data, and normalization of the interferometric correlation coefficient.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: ESA, Proceedings of 2nd ERS-1 Symposium on Space at the Service of Our Environment, Volume 2; p 711-715
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  • 45
    facet.materialart.
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    In:  CASI
    Publikationsdatum: 2004-12-03
    Beschreibung: Millisecond pulsars are galactic objects that exhibit a very stable spinning period. Several tens of these celestial clocks have now been discovered, which opens the possibility that an average time scale may be deduced through a long-term stability algorithm. Such an ensemble average makes it possible to reduce the level of the instabilities originating from the pulsars or from other sources of noise, which are unknown but independent. The basis for such an algorithm is presented and applied to real pulsar data. It is shown that pulsar time could shortly become more stable than the present atomic time, for averaging times of a few years. Pulsar time can also be used as a flywheel to maintain the accuracy of atomic time in case of temporary failure of the primary standards, or to transfer the improved accuracy of future standards back to the present.
    Schlagwort(e): ASTROPHYSICS
    Materialart: NASA. Goddard Space Flight Center, The 24th Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting; p 73-86
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  • 46
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2004-12-03
    Beschreibung: Research on the use of active microwaves in remote sensing, presented during plenary and poster sessions, is summarized. The main highlights are: calibration techniques are well understood; innovative modeling approaches have been developed which increase active microwave applications (segmentation prior to model inversion, use of ERS-1 scatterometer, simulations); polarization angle and frequency diversity improves characterization of ice sheets, vegetation, and determination of soil moisture (X band sensor study); SAR (Synthetic Aperture Radar) interferometry potential is emerging; use of multiple sensors/extended spectral signatures is important (increase emphasis).
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 1219-1221
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  • 47
    Publikationsdatum: 2004-12-03
    Beschreibung: Crop residues, the portion of the crop left in the field after harvest, can be an important management factor in controlling soil erosion. Methods to quantify residue cover are needed that are rapid, accurate, and objective. Scenes with known amounts of crop residue were illuminated with long wave ultraviolet (UV) radiation and fluorescence images were recorded with an intensified video camera fitted with a 453 to 488 nm band pass filter. A light colored soil and a dark colored soil were used as background for the weathered soybean stems. Residue cover was determined by counting the proportion of the pixels in the image with fluorescence values greater than a threshold. Soil pixels had the lowest gray levels in the images. The values of the soybean residue pixels spanned nearly the full range of the 8-bit video data. Classification accuracies typically were within 3(absolute units) of measured cover values. Video imaging can provide an intuitive understanding of the fraction of the soil covered by residue.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 923-928
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  • 48
    Publikationsdatum: 2004-12-03
    Beschreibung: Global study of land surface properties uses AVHRR channels 1 and 2, but channel 3 may be of interest, although its use requires preprocessing. It consists of both a reflective part and an emissive part, the former can be derived from T3, T4 and T5. Since the water vapor affects channel 3, its content is retrieved from the channel 4 and 5 using the split window technique. A formula of reflective part retrieval at 3.75 micrometers is tested in the case of sunglint observations where the emissivities of channels 4 and 5 can be set to the unity. The formula is adapted and validated to land surface using the FIFE-87 data set. Preliminary applications of the reflectance at 3.75 micrometers to the studies of surface properties retrieval, aerosol retrieval over land, and desertic aerosol retrieval, are addressed.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 817-824
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  • 49
    Publikationsdatum: 2004-12-03
    Beschreibung: The polarization of the sunlight scattered by atmospheric aerosols or cloud droplets and reflected from ground surfaces or plant canopies may convey much information when used for remote sensing purposes. The typical polarization features of aerosols, cloud droplets, and plant canopies, as observed by ground based and airborne sensors, are investigated, looking especially for those invariant properties amenable to description by simple models when possible. The question of polarization measurements from space is addressed. The interest of such measurements for remote sensing purposes is investigated, and their feasibility is tested by using results obtained during field campaigns of the airborne POLDER instrument, a radiometer designed to measure the directionality and polarization of the sunlight scattered by the ground atmosphere system.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 569-580
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  • 50
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    In:  CASI
    Publikationsdatum: 2004-12-03
    Beschreibung: The knowledge of vegetation dielectric behavior is important in studying the scattering properties of the vegetation canopy and radar backscatter modelling. Until now, a limited number of studies have been published on the dielectric properties in the boreal forest context. This paper presents the results of the dielectric constant as a function of depth in the trunks of two common boreal forest species: black spruce and trembling aspen, obtained from field measurements. The microwave penetration depth for the two species is estimated at C, L, and P bands and used to derive the equivalent dielectric constant for the trunk as a whole. The backscatter modelling is carried out in the case of black spruce and the results are compared with the JPL AIRSAR data. The sensitivity of the backscatter coefficient to the dielectric constant is also examined.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: JPL, Summaries of the 4th Annual JPL Airborne Geoscience Workshop. Volume 3: AIRSAR Workshop; p 89-92
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  • 51
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    In:  CASI
    Publikationsdatum: 2004-12-03
    Beschreibung: Papers focused on land surface, atmospheric, and ocean properties are reported. Specific comments pertaining to polarization, models and inversion, and measurements, are given. Recommendations are: continued research into the application potential of the BRDF (Bidirectional Reflectance Distribution Function) and polarization properties of ground surface and atmospheric targets; three dimensional models, which account for the statistical behavior of remotely sensed data, should be extended and inverted in order to support analysis of data potentially covering rolling terrain such that pixels represent heterogeneous mixtures of surface cover types and project ground footprints with sizes between 10 to 6 km, the ground pixel sizes of planned future sensors; available reflectance models should be further validated by means of multi dimensional (directional, spectral, temporal) field data and existing models should be intercompared in more depth to evaluate their performance and limitations; existing methods for model inversion should be validated in more depth in order to quantify the practical limitations and the expected accuracy of the parameters retrieved and new approaches should be developed based upon apriori knowledge of plant canopy development and spectral BRDF properties; there is a need to establish a protocol of validation and intercomparison of the indices and compositing techniques which have been proposed during these last years.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 1225-1227
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  • 52
    Publikationsdatum: 2004-12-03
    Beschreibung: Traditionally, the remote sensing community has relied totally on spectral knowledge to extract vegetation characteristics. However, there are other knowledge bases (KB's) that can be used to significantly improve the accuracy and robustness of inference techniques. Using AI (artificial intelligence) techniques a KB system (VEG) was developed that integrates input spectral measurements with diverse KB's. These KB's consist of data sets of directional reflectance measurements, knowledge from literature, and knowledge from experts which are combined into an intelligent and efficient system for making vegetation inferences. VEG accepts spectral data of an unknown target as input, determines the best techniques for inferring the desired vegetation characteristic(s), applies the techniques to the target data, and provides a rigorous estimate of the accuracy of the inference. VEG was developed to: infer spectral hemispherical reflectance from any combination of nadir and/or off-nadir view angles; infer percent ground cover from any combination of nadir and/or off-nadir view angles; infer unknown view angle(s) from known view angle(s) (known as view angle extension); and discriminate between user defined vegetation classes using spectral and directional reflectance relationships developed from an automated learning algorithm. The errors for these techniques were generally very good ranging between 2 to 15% (proportional root mean square). The system is designed to aid scientists in developing, testing, and applying new inference techniques using directional reflectance data.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 581-592
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  • 53
    Publikationsdatum: 2004-12-03
    Beschreibung: Most earth surfaces, particularly those supporting natural vegetation ecosystems, constitute structurally and spectrally complex surfaces that are distinctly non-Lambertian reflectors. Obtaining meaningful measurements of the directional radiances of landscapes and obtaining estimates of the complete bidirectional reflectance distribution functions of ground targets with complex and variable landscape and radiometric features are challenging tasks. Reasons for the increased interest in directional radiance measurements are presented, and the issues that must be addressed when trying to acquire directional radiances for vegetated land surfaces from different types of remote sensing platforms are discussed. Priority research emphases are suggested, concerning field measurements of directional surface radiances and reflectances for future research. Primarily, emphasis must be given to the acquisition of more complete and directly associated radiometric and biometric parameter data sets that will empower the exploitation of the 'angular dimension' in remote sensing of vegetation through enabling the further development and rigorous validation of state of the art plant canopy models.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 561-567
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  • 54
    Publikationsdatum: 2004-12-03
    Beschreibung: Synthetic aperture radar (SAR) images of the Greenland ice sheet collected by an airborne system clearly reveal the four melting facies of this sheet defined 30 years ago from snow stratigraphy studies by glaciologists. In particular, the radar echoes from the percolation facies have radiometric and polarimetric characteristics that are unique among terrestrial surfaces, but that resemble the exotic radar echoes recorded from the icy Galilean satellites. There, the radar signals interact with subsurface, massive ice features created in the cold, dry snow by seasonal melting and refreezing events. The subsurface features act as efficient reflectors of the incident radiation most likely via internal reflections. In the soaked-snow facies, the radar reflectivity is much lower because radar signals are attenuated by the wetter snow before they can interact with subsurface structures. Inversion algorithms to derive geophysical information from the SAR data are developed in both cases to estimate snow wetness in the soaked-snow facies and the mass of ice water retained in the percolation facies.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 431-436
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  • 55
    Publikationsdatum: 2004-12-03
    Beschreibung: An operational stratospheric correction scheme used after the Mount Pinatubo (Phillipines) eruption (Jun. 1991) is presented. The stratospheric aerosol distribution is assumed to be only variable with latitude. Each 9 days the latitudinal distribution of the optical thickness is computed by inverting radiances observed in the NOAA AVHRR channel 1 (0.63 micrometers) and channel 2 (0.83 micrometers) over the Pacific Ocean. This radiance data set is used to check the validity of model used for inversion by checking consistency of the optical thickness deduced from each channel as well as optical thickness deduced from different scattering angles. Using the optical thickness profile previously computed and radiative transfer code assuming Lambertian boundary condition, each pixel of channel 1 and 2 are corrected prior to computation of NDVI (Normalized Difference Vegetation Index). Comparison between corrected, non corrected, and years prior to Pinatubo eruption (1989 to 1990) NDVI composite, shows the necessity and the accuracy of the operational correction scheme.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 151-158
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  • 56
    Publikationsdatum: 2004-12-03
    Beschreibung: Aspects of aerosol studies and remote sensing are reviewed. Aerosol scatters solar radiation before it reaches the surface and scatters and absorbs it again after it is reflected from the surface and before it reaches the satellite sensor. The effect is spectrally and spatially dependent. Therefore atmospheric aerosol (dust, smoke and air pollution particles) has a significant effect on remote sensing. Correction for the aerosol effect was never achieved on an operational basis though several case studies were demonstrated. Correction can be done in a direct way by deriving the aerosol loading from the image itself and correcting for it using the appropriate radiative transfer model or by an indirect way, by defining remote sensing functions that are less dependent on the aerosol loading. To some degree this was already achieved in global remote sensing of vegetation where a composite of several days of NDVI (Normalized Difference Vegetation Index) measurements, choosing the maximal value, was used instead of a single cloud screened value. The Atmospheric Resistant Vegetation Index (ARVI) introduced recently for the NASA Earth Observing System EOS-MODIS is the most appropriate example of indirect correction, where the index is defined in such a way that the atmospheric effect in the blue spectral channel cancels to a large degree the atmospheric in the red channel in computations of a vegetation index. Atmospheric corrections can also use aerosol climatology and ground based instrumentation.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 7-19
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  • 57
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    In:  CASI
    Publikationsdatum: 2004-12-03
    Beschreibung: A session dedicated to high spectral resolution in the solar spectrum, covering topics of calibration, atmospheric correction, geology/pedology, inland water, and vegetation, is reported. The session showed a high degree of diversity in the topics and the approaches used. It was highlighted that high spectral resolution data could provide atmospherically corrected ground level calibrated reflectance values. Important advances were shown in the use of radiative transfer models applied either on water bodies or vegetation. Several studies highlighted the high degree of redundancy contained in high spectral resolution data.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: CNES, Proceedings of 6th International Symposium on Physical Measurements and Signatures in Remote Sensing; p 1217-1218
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  • 58
    Publikationsdatum: 2011-08-24
    Beschreibung: We study the transfer of momentum from photons to dust grains to (molecular) gas in the outflow around cool giants (carbon-stars, Mira variables and OH/IR stars) beyond the radius where the dust grains condense. The problem is circular: radiation pressure determines the outflow velocity of the dust and thus also the dust density; on the other hand the dust density determines, via radiative transfer effects, the spectrum of the photons and thus the effective radiation pressure. This circular problem is solved by a rapidly converging iterative procedure. We compare our predictions with observed properties of a large sample of OH/IR stars and of Miras and find a good qualitative and quantitative agreement. We confirm a conclusion by Wood et al. (1993) that very luminous OH/IR stars in the Large Magellanic Cloud (LMC) owe their low outflow velocity to the low dust-to-gas ratio, a consequence of the low metallicity of the LMC. Similarly we consider a sample of about 100 OH/IR stars within 200 pc from the galactic center that has an average asymptotic giant branch (AGB) luminosity and an uncommonly high value of v(sub out); we conclude that these stars are probably very metal rich, perhaps even more than the stars in the Baade window studied by Rich (1990).
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astronomy and Astrophysics (ISSN 0004-6361); 286; 2; p. 523-534
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  • 59
    Publikationsdatum: 2011-08-24
    Beschreibung: Magnetic field data measured by the MAGMA instrument in the Martian magnetotail lobes are compared with the ram pressure of the upstream solar wind observed by the TAUS instrument in the circular orbits of the Phobos 2 spacecraft. High correlation was found between the magnetic field intensity in the Martian magnetotail lobes and the solar wind ram pressure. From this relationship the average flaring angle of the Martian magnetotail was determined as approximately 13 deg, and the average magnetosonic Mach number was estimated as approximately 5. The observed relationship between the Martian magnetotail magnetic field intensity and the solar wind magnetic field reflects the correlation of the solar wind magnetic field to the ram pressure providing a value of approximately 7 for the average Alfvenic Mach number. The flaring angle obtained for the Martian magnetotail was found to be an intermediate value between the flaring angle of the magnetotail of the Earth and that of Venus at comparable distances.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Journal of Geophysical Research (ISSN 0148-0227); 99; A9; p. 17,199-17,204
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  • 60
    Publikationsdatum: 2011-08-24
    Beschreibung: We present a model of the focused transport of approximately 1 MeV solar energetic protons through interplanetary Alfven waves that the protons themselves amplify or damp. It is based on the quasi-linear theory but with a phenomenological pitch angle diffusion coefficient in the 'resonance gap.' For initial Alfven wave distributions that give mean free paths greater than approximately 0.5 AU for approximately 1 MeV protons in the inner heliosphere, the model predicts greater than roughly an order of magnitude amplification (damping) in the outward (inward) propagating resonant Alfven waves at less than or approximately equal to o.3 AU heliocentric distance. As the strength of proton source is increased, the peak differential proton intensity at approximately 1 MeV at 1 AU increases to a maximum of approximately 250 particles (/(sq cm)(s)(sr)(MeV)) and then decreases slowly. It may be attenuated by a factor of 5 or more relative to the case without wave evolution, provided that the proton source is sufficiently intense that the resulting peak differential intensity of approximately 1 MeV protons at 1 AU exceeds approximately 200 particles (/(sq cm)(s)(sr)(MeV)). Therefore, in large solar proton events, (1) one may have to take into account self-amplified waves in studying solar particle propagation, (2) the number of accelerated protons escaping from a flare or interplanetary shock may have been underestimated in past studies by a significant factor, and (3) accelerated protons escaping from a traveling interplanetary shock at r less than or approximately equal to 0.3 AU should amplify the ambient hydromagnetic waves siginificantly to make the shock an efficient accelerator, even if initially the mean free path is greater than or approximately equal to 1 AU.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 424; 2; p. 1032-1048
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  • 61
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    Publikationsdatum: 2011-08-24
    Beschreibung: Direct one-photon annihilation rate of positrons with a bound atomic electron is evaluated in the nonrelativistic limit. The K- and L-shell contributions are estimated including the screening and effective Coulomb repulsion effects. The annihilation rate of thermal positrons is calculated for various temperatures. The total number of one-photon annihilation events in the interstellar medium is discussed. These results provide the directional and structural information for cosmic gamma-ray sources.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 424; 2; p. 988-990
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  • 62
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    Publikationsdatum: 2011-08-24
    Beschreibung: The origin of tektites has been obscure because of the following dilemma. The application of physical principles to the data available on tektites points strongly to origin from one or more lunar volcanoes; but few glasses of tektite composition have hitherto been reported from the lunar samples. Instead, the lunar silicic glasses consist chiefly of a material very rich in K2O and poor in MgO. The ratio of K2O/MgO is higher in these glasses than in any tektites reported. The solution of the dilemma seems to come from the study of some recently discovered terrestrial deposits of tektite glass with high values of K2O/MgO at the Cretaceous Tertiary boundary. These glasses are found to be very vulnerable to crystallization into sandine or to alteration to smectite. These end products are known and are more abundant than any terrestrial deposits of tektite glass. It seems possible that, in fact, the moon produces tektite glass, mostly of the high K2O-low MgO type; but on Earth these deposits are destroyed. The much less abundant deposits with lower K and higher Mg are observed because they survive. Other objections to the lunar origin hypothesis appear to be answerable.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Meteoritics (ISSN 0026-1114); 29; 1; p. 73-78
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  • 63
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    In:  Other Sources
    Publikationsdatum: 2011-08-24
    Beschreibung: We investigate the radiative shock overstability for finite-sized objects. We follow the analysis of Chevalier & Imamura (1982), but we take into account the transverse flow of material out of the potshock region. The mass loss from the postshock region stabilizes the flow. As a rough estimate, the shock radiative instability takes place when the shock wave position with no radiative cooling (only mass loss present) is larger than the shock position with no mass loss (only radiative cooling present). For typical conditions of planetary nebulae we find that in order for the shock radiative overstability to occur, the nebular radius should be R approximately less than 10(exp 19) n(sub a)(exp -1) cm, where n(sub alpha) is the total number density of the interstellar medium (in units of cm(exp -3). We give several examples of interacting planetary nebulae in light of this condition.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 434; 1; p. 262-267
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  • 64
    Publikationsdatum: 2011-08-24
    Beschreibung: Spectral absorption-coefficients (cross-sections) kappa(sub nu) (/cm/atm) have been measured in the 7.62, 8.97, and 12.3 micrometer bands of HCFC-22 (CHClF2) and the 10.6 micrometer bands of SF6 employing a high-resolution Fourier-transform spectrometer. Temperature and total pressure have been varied to simulate conditions corresponding to tropospheric and stratospheric layers in the atmosphere. The kappa(sub nu) are compared with values measured by us previously using a tunable diode laser spectrometer and with the appropriate entries in HITRAN and GEISA, two of the databases known to the atmospheric scientist. The measured absolute intensities of the bands are compared with previously published values.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: Journal of Quantitative Spectroscopy & Radiative Transfer (ISSN 0022-4073); 52; 3-4; p. 323-332
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  • 65
    Publikationsdatum: 2011-08-24
    Beschreibung: We compare model predictions of cometary water group ion densities and the solar wind slow down with measurements made by the Giotto Johnstone plasma analyzer implanted ion sensor at the encounter with comet Grigg-Skjellerup (G-S) on July 10, 1992. The observed slope of the ion density profile on approach to the comet is unexpectedly steep. Possible explanations for this are discussed. We present also a preliminary investigation of the quasilinear velocity-space diffusion of the implanted heavy ion population at G-S using a transport equation including souce, convection, adiabatic compression, and velocity diffusion terms. Resulting distributions are anisotropic, in agreement with observations. We consider theoretically the waves that may be generated by the diffusion process for the observed solar wind conditions. At initial ion injections, waves are generated at omega approximately Omega(sub i) the ion gyrofrequency, and lower frequencies are predicted for diffusion toward a bispherical shell.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Journal of Geophysical Research (ISSN 0148-0227); 98; A12; p. 20,995-21,002
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  • 66
    Publikationsdatum: 2011-08-24
    Beschreibung: Large-amplitude ultralow-frequency wave structure observed on both sides of the magnetic pileup boundary of comet P/Halley during the flyby of the Giotto spacecraft have been analyzed using suprathermal electron density and magnetic field observations. Upstream of the boundary, electron density and magnetic field magnitude variations are anticorrelated, while in the pileup region these quantities are clearly correlated. Both in front of and behind the pileup boundary the observed waves are quasi-perpendicular wave structures as a minimum variance analysis shows. A detailed comparison of our observations in the prepileup region with theoretical and numerical results shows that the mirror mode mode waves may have been generated by a mirror instability driven by the pressure anisotropy of the ring-type distributions of the heavy (water group) pickup cometary ions.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Journal of Geophysical Research (ISSN 0148-0227); 98; A12; p. 20,955-20,964
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  • 67
    Publikationsdatum: 2011-08-24
    Beschreibung: The energy spectra of the black-hole candidate GX 339-4 in the low-intensity state were observed on four occasions through 1989 to 1991 with the Large Area Counter on board the Ginga satellite. The spectra showed significant deviations from a power-law, with an iron K(sub alpha) emission line at approximetaly 6.4 keV and a broad iron K-edge structure above approximately 7 keV. The enrgy spectra above approximately 4 keV were successfully explained with a reflection model, in which part of the incident X-rays with a power-law spectrum is Compton reflected by optically thick matter, resulting in a harder continuum component with iron K-edge absorption and an iron flourescent line. The line equivalent width with respect to the reflection component decreases as the source flux increases. This is consistent with an increase in the ionization state of the material, so that resonant absorption followed by Auger ionization depletes the line. The photon-index of the power-law component was clearly variable, and it correlated with the relative amount of the reflection component. Such a correlation may be explained in the context of the anisotropic Comptonization models of Haardt et al. (1993), or by a variation of the relative geometry of the source and disk.
    Schlagwort(e): ASTROPHYSICS
    Materialart: PASJ: Publications of the Astronomical Society of Japan (ISSN 0004-6264); 46; 1; p. 107-115
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  • 68
    Publikationsdatum: 2011-08-24
    Beschreibung: We suggest that prior to its impact with Jupiter, comet Shoemaker-Levy 9 will behave as an electrical generator in the Jovian magnetosphere, converting planetary rotational energy to electrical energy via a dust/plasma interaction. This electrical energy will then be deposited in the dayside auroral region where it may drive various auroral phenomena including cyclotron radio emission. Such emission could be detected by spacecraft like Ulysses and Galileo many hours prior to the actual comet impact with the upper atmosphere. We apply the theory originally developed to explain the spokes in Saturn's rings. This theory allows us to quantify the driving potential associated with the comet and, consequently, to determine the radio power created in the auroral region. We conclude that if enough fine dust is present in the cometary system, comet-induced auroral radio emissions will reach detectable levels. This emission should be observable in the dayside hemisphere about 12-24 hours prior to each fragment impact.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Geophysical Research Letters (ISSN 0094-8276); 21; 11; p. 1067-1070
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  • 69
    Publikationsdatum: 2011-08-24
    Beschreibung: The Far-Infrared Absolute Spectrophotometer (FIRAS) instrument on the Cosmic Background Explorer (COBE) has determined the dipole spectrum of the cosmic microwave background radiation (CMBR) from 2 to 20/cm. For each frequency the signal is decomposed by fitting to a monopole, a dipole, and a Galactic template for approximately 60% of the sky. The overall dipole spectrum fits the derivative of a Planck function with an amplitude of 3.343 +/- 0.016 mK (95% confidence level), a temperature of 2.714 +/- 0.022 K (95% confidence level), and an rms deviation of 6 x 10(exp -9) ergs/sq cm/s/sr cm limited by a detector and cosmic-ray noise. The monopole temperature is consistent with that determined by direct measurement in the accompanying article by Mather et al.
    Schlagwort(e): ASTROPHYSICS
    Materialart: The Astrophysical Journal, Part 1 (ISSN 0004-637X); 420; 2; p. 445-449
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  • 70
    Publikationsdatum: 2011-08-24
    Beschreibung: Theoretical O I density-sensitive emission-line ratios R = I(2s(sup 2))(2p(sup 4))((sup 3)P(sub 0))-((2s(sup 2))(2p(sup 4))((sup 3)P(sub 1)))/I((2s(sup 2))(2p(sup 4))((sup 3)P(sub 1))-(2s(sup 2))(2p(sup 4))((sup 3)P(sub 2))) = I(146 micrometers)/I(63 micrometers) are presented for a range of temperatures (T = 100-10,000 K), neutral hydrogen densities (N(sub H) = 10(exp -2) to 10(exp 7)/cu cm) and radiation fields (G(sub 0) = 1-10(exp 6)) applicable to both photodissociation regions (PDRs) and H II regions and the diffuse ionized medium (DIM). The observed values of R for several PDRs, measured from far-infrared spectra obtained with the Kuiper Airborne Observatory (KAO), imply hydrogen densities which are in good agreement with those determined using other methods. This provides observational support for the validity of the theoretical O I line ratios, and hence the atomic data used in their derivation.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 434; 2; p. 811-815
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  • 71
    Publikationsdatum: 2011-08-24
    Beschreibung: The 1.6-1.8 micron spectrum of the planetary nebula, IRAS 21282+5050, a strong emitter of the unidentified interstellar bands, contains a 0.02 micron wide eimission feature centered at 1.680 micron, which is well matched by laboratory spectra of the 0-2 CH stretching mode in polycyclic aromatic hydrocarbons (PAHs). We identify the new feature as the overtone of the well-known 3.3 micron band. In view of the high excitation required for emission in this band, the identification indicates that the emission is by free molecules rather than molecular moieties in solid dust grains. Modeling of the intensity ratio of the 2-0 to 1-0 band implied that the PAHs emitting in these bands contain about 60 carbon atoms. It is inferred that the nu = 2-1 hot band of the CH stretching mode occurs at about 3.43 micron and contributes to the long-wavelength shoulder of the 3.40 micron feature. The main 3.40 micron feature probably is due to aliphatic sidegroups on PAH molecules.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X); 434; 1; p. L15-L18
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  • 72
    Publikationsdatum: 2011-08-24
    Beschreibung: Weakly nonlinear Magneto Hydrodynamic (MHD) stability of the Halley cometosheath determined by the balance between the outward ion-neutral drag force and the inward Lorentz force is investigated including the transverse plasma motion as observed in the flanks with the help of the method of multiple scales. The eigenvalues and the eigenfunctions are obtained for the linear problem and the time evolution of the amplitude is obtained using the solvability condition for the solution of the second order problem. The diamagnetic cavity boundary and the adjacent layer of about 100 km thickness is found unstable for the travelling waves of certain wave numbers. Halley ionopause has been observed to have strong ripples with a wavelength of several hundred kilometers. It is found that nonlinear effects have stabilizing effect.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysics and Space Science (ISSN 0004-640X); 222; 1-2; p. 113-125
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  • 73
    Publikationsdatum: 2011-08-24
    Beschreibung: We have developed a radiative transfer model of the dust and gas envelopes around late-type stars. The gas kinetic temperature for each star is calculated by solving equations of motion and the energy balance simultaneously. The main processes include viscous heating and adiabatic and radiative cooling. Heating is dominated by viscosity as the grains stream outward through the gas, with some contribution in oxygen-rich stars by near-IR pumping of H2O followed by collisional de-excitation in the inner envelope. For O-rich stars, rotational H2O cooling is a dominant mechanism in the middle part of the envelope, with CO cooling being less significant. We have applied our model to three well-studied oxygen-rich red giant stars. The three stars cover a wide range of mass-loss rates, and hence they have different temperature structures. The derived temperature structures are used in calculating CO line profiles for these objects. Comparison of the dust and gas mass-loss rates suggests that mass-loss rates are not constant during the asymptotic giant branch phase. In particular, the results show that the low CO 1-0 antenna temperatures of OH/IR stars reflect an earlier phase of much lower mass-loss rate.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 435; 2; p. 852-863
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  • 74
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    Publikationsdatum: 2011-08-24
    Beschreibung: Solid state SiS2 is proposed as the material responsible for the recently discovered 21 micrometer emission feature that is observed in the carbon-rich circumstellar shells of certain protoplanetary nebulae. Sulfurized SiC, or SiS2 mantles on grains of either SiC or a:C-H are discussed as possible forms for which no spectroscopic laboratory observations yet exist. The identification with a relatively minor species and required special abundance ratios are consistent with the low incidence rate that the 21 micrometer feature presents in the population of carbon rich objects. It is also consistent with the lack of a good correlation between the 21 micrometer feature and the other solid-state spectroscopic features that have been observed in protoplanetaries that would be expected if the feature arose from molecules composed of H, C, N, and O. SiS2 condensate is consistent with the circumstellar shell temperature range, T(sub CS) approximately equal to or less than 150 K, at which the feature appears, and the available mass of SiS2, M(sub SiS2) approx. = 5 x 10(exp -6) solar mass, that is possible in the circumstellar shell.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astronomy and Astrophysics (ISSN 0004-6361); 278; 1; p. 226-230
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  • 75
    Publikationsdatum: 2011-08-24
    Beschreibung: We have studied the spectacular 1991 June X-class flares using gamma-ray data from the Charged Particle Detectors (CPDs) of the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) and 80 GHz millimeter data from Nobeyama, Japan. The CPDs were the only CGRO instrument that did not saturate during the extremely intense 1991 June 4 flare. We have shown that for this flare the CPDs respond to MeV photons, most of which are due to bremsstrahlung produced by relativistic electrons at the Sun. We have further shown that the gamma-ray and millimeter observations agree numerically if the 80 GHz radiation is gyrosynchrotron radiation produced by trapped electrons and the gamma rays are thick-target bremsstrahlung due to electrons precipitating out of the trap. The requirement that the trapping time obtained from the numerical comparison be consistent with the observed time profiles implies a magnetic field between about 200 and 300 G and an electron spectral index between about 3 to 5. By comparing the CPD observations with both the 80 GHz data and nuclear line data from the Energetic Gamma Ray Experiment Telescope (EGRET) and the Oriented Scintillation Spectroscopy Experiment (OSSE) on CGRO for the flares of June 4, 6, 9, and 11, we found that the ratio of the CPD counts to both the millimeter flux densities and the nuclear line fluences decreases with decreasing flare heliocentric angle. All of these flares were produced in the same active region. We interpreted this result in terms of a loop model in which the gyrosynchrotron emission is produced in the coronal portion of the loop where the electrons are kept isotropic by pitch angle scattering due to plasma turbulence, while the bremsstrahlung is produced by precipitating electrons that interact anisotropically. We found that the trapping time in the coronal portion is time dependent, reaching a minimum of about 10 s at the peak of the CPD count rate. We suggested the damping of the turbulence as a possible reason for the variation of the trapping time. turbulence as a possible reason for the variation of the trapping time.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 436; 2; p. 941-949
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  • 76
    Publikationsdatum: 2011-08-24
    Beschreibung: Several possible models have been suggested to explain the observed distribution of gamma-ray bursts: heliocentric distributions such as the Oort cloud, large galactic halos, and cosmological models. We report here on an investigation into the implications of the Burst and Transient Source Experiment (BATSE) gamma-ray burst distribution (Meegan et al. 1992a) data on the possible helocentric origin of gamma-ray bursts. We find no statistically significant anisotropy in the angular distribution of the bursts in a Sun-referenced coordinate system; there is no dipole moment in the direction of the Sun, and no quardrupole moment associated with the ecliptic plane. We have employed direct analytic calculations and Monte Carlo simulations of sources in the Oort cloud to constrain possible helicentric burst distributions. These can produce distributions consistent with the observed angular isotropy, the meal value of V/V(sub max), and the observed C/C(sub min) distribution of BATSE, and provide limits to burst energy of a few times approximately 10(exp 27) ergs. However, the agreement of the heliocentric C/C(sub min) distributions with the BATSE data is attributable to the relatively limited sampling of strong, nearby bursts. These bursts are known from observation to be homogeneously distributed, yet the density of sources in the Oort cloud is not constant in this region. Integral number-intensity distributions from the Oort cloud for larger numbers of bursts cannot reproduce the known homogeneity of the strong bursts without modification to the computed cometary number density and are therefore unlikely explanations of the gamma-ray burst distribution.
    Schlagwort(e): ASTROPHYSICS
    Materialart: The Astrophysical Journal, Part 1 (ISSN 0004-637X); 429; 1; p. 319-324
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  • 77
    Publikationsdatum: 2011-08-24
    Beschreibung: We report the first X-ray observations of the Seyfert 1 galaxy MCG-6-30-15 obtained at medium spectral resolution. The partially-ionized, 'warm' absorber is resolved and shown to be due to O VII and O VIII. The main absorption edge agrees with that of O VII at the redshift of the galaxy to within 1%. The column density of the absorbing material is greater by a factor of 2 in the first of our two obsevations, which were 3 weeks apart, while the mean flux is slightly lower and the ionization parameter slightly higher. We also discuss the flourescent iron emssion line seen in the source, which is at 6.40 keV. The line is significantly broadened, with a Full Width at Half Maximum (FWHM) of about 0.4 keV.
    Schlagwort(e): ASTROPHYSICS
    Materialart: PASJ: Publications of the Astronomical Society of Japan (ISSN 0004-6264); 46; 3; p. L59-L63
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  • 78
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    In:  Other Sources
    Publikationsdatum: 2011-08-24
    Beschreibung: Near supernova 1987a, the rare honeycomb structure of 20-30 galactic bubbles measures 30 x 90 light years. Its remarkable regularity in bubble size suggests a single-event origin which may correlate with the nearby supernova. To test the honeycomb's regularity in shape and size, the formalism of statistical crystallography is developed here for bubble sideness. The standard size-shape relations (Lewis's law, Desch's law, and Aboav-Weaire's law) govern area, perimeter and nearest neighbor shapes. Taken together, they predict a highly non-equilibrium structure for the galactic honeycomb which evolves as a bimodal shape distribution without dominant bubble perimeter energy.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysics and Space Science (ISSN 0004-640X); 220; 1; p. 65-74
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  • 79
    Publikationsdatum: 2011-08-24
    Beschreibung: If, as many believe, Sgr A* is a massive black hole at the Galactic center, one should expect it to be a source of X-ray and gamma-ray activity, behaving basically as a scaled-down active galactic nucleus. An unavoidable source of accretion is the wind from IRS 16, a nearby group of hot, massive stars. Since the density and velocity of the accreting matter are known from observations, the accretion rate is basically a function of the putative black hole mass, M(sub h), only; this value represents a reliable lower limit to a real rate, given the other possible sources of accreting matter. Based on this and on the theories about shock acceleration in active galactic nuclei, we have estimated the expected production of relativistic particles and their hard radiation. These values turn out to be a function of M(sub h) as well. Comparing our results with available X-ray and gamma-ray observations which show Sgr A* to have a relatively low activity level, we conclude tentatively that the putative black hole in the Galactic center cannot have a mass greater than approximately 6 x 10(exp 3) solar mass. This conclusion is consistent with the upper limits to the black hole mass found by different methods earlier, although much more work is needed to make calculations of shock acceleration around black holes more reliable.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 426; 2; p. 599-603
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  • 80
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    In:  Other Sources
    Publikationsdatum: 2011-08-24
    Beschreibung: The light curve of the Type Ia supernova SN 1937C (in IC 4182) is important because Sandage et al. have measured a distance to the host galaxy by means of Cepheid variables and thus have derived the Hubble constant. However, the peak brightness of SN 1937C has only been derived with the relatively poor original comparison star brightnesses and without regard to a large body of data in the literature. In this paper, I will correct these and other procedural difficulties. I find that the late time photographic light curve appears to have a broken exponential decay with equivalent half-lives of 46 and 58 days with the break near 300 days after maximum. I also find that the peak B-magnitude was 8.71 +/- 0.14 on JD 2428770.0 +/- 1.0 at which time the B-V was -0.03 +/- 0.13. With these improved peak brightnesses, the distance modulus of Sandage et al., and peak absolute magnitudes in the center of the range of modern estimates, I derive the Hubble constant to be 50 km/s Mpc.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 426; 2; p. 493-501
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  • 81
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    In:  Other Sources
    Publikationsdatum: 2011-08-24
    Beschreibung: We have found a new way to make Thorne-Zytkow objects, which are massive stars with degenerate neutron cores. The asymmetric kick given to the neutron star formed when the primary of a massive tight binary system explodes as a supernova sometimes has the appropriate direction and amplitude to place the newly formed neutron star into a bound orbit with a pericenter distance smaller than the radius of the secondary. Consequently, the neutron star becomes embedded in the secondary. Thorne-Zytkow objects are expected to look like extreme M-type supergiants, assuming that they can avoid a runaway neutrino instability. Accretion onto the embedded neutron star will produce either an isolated, spun-up neutron star (possibly a short-period pulsar) or a black hole. Whether neutron star or black hole remnants predominate depends on the lifetime of Thorne-Zytkow objects, the accretion rates involved, and the maximum neutron star mass, none of which are definitively understood.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X); 423; 1; p. L19-L22
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  • 82
    Publikationsdatum: 2011-08-24
    Beschreibung: Observations of the red supergiant (M2 Iab) alpha Ori with the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope (HST) have provided an unambiguous detection of a far-ultraviolet (far-UV) chromospheric continuum on which are superposed strong molecular absorption bands. The absorption bands have been identified by Carpenter et al. (1994) with the fourth-positive A-X system of CO and are likely formed in the circumstellar shell. Comparison of these GHRS data with archival International Ultraviolet Explorer (IUE) spectra of alpha Ori indicates that both the continuum and the CO absorption features can be seen with IUE, especially if multiple IUE spectra, reduced with the post-1981 IUESIPS extraction procedure (i.e., with an oversampling slit), are carefully coadded to increase the signal to noise over that obtainable with a single spectrum. We therefore initiated a program, utilizing both new and archival IUE Short Wavelength Prime (SWP) spectra, to survey 15 cool, low-gravity stars, including alpha Ori, for the presence of these two new chromospheric and circumstellar shell diagnostics. We establish positive detections of far-UV stellar continua, well above estimated IUE in-order scattered light levels, in spectra of all of the program stars. However, well-defined CO absorption features are seen only in the alpha Ori spectra, even though spectra of most of the program stars have sufficient signal to noise to allow the dectection of features of comparable magnitude to the absorptions seen in alpha Ori. Clearly if CO is present in the circumstellar environments of any of these stars, it is at much lower column densities.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astronomical Journal (ISSN 0004-6256); 107; 2; p. 747-750
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  • 83
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    In:  Other Sources
    Publikationsdatum: 2011-08-24
    Beschreibung: The giant radio galaxy NGC 6251 is a particularly good object for observational tests of relativistic jet models. Due to its high declination and approximately 0.5 Jy radio nucleus, high-quality Very Long Baseline Interferometry (VLBI) images of the central regions of the source can be made with northern hemisphere arrays. In addition, the large-scale radio morphology strongly suggests that the radio axis lies close to the plane of the sky, so Doppler boosting should be less extreme than in the core-dominated superluminal sources. Earlier 18 cm VLBI observations of NGC 6251 revealed an unexpectedly large jet/counterjet brightness ratio and small transverse motion of a feature in the parsec-scale jet. These early results are difficult to reconcile with the simplest symmetric relativistic jet models. In this paper we present a third-epoch 18 cm VLBI image of the parsec-scale radio jet in NGC 6251, and compare jet morphology over a 5 year time span. The jet shows a minor brightness peak at nearly the same distance from the core as the '25 mas knot' seen in the first- and second-epoch VLBI images. This feature is much less pronounced in the third epoch, and a relatively bright, new knot has appeared approximately 12 mas from the core. If this new component had a constant brightness during the 5 years separating the first and third observing epochs, then it must have moved away from the core with an apparent speed of at least 1.2c (compared with an upper limit of 0.23c for motion of the 25 mas knot). However, we cannot yet rule out a local brightening of the inner jet in favor of a new moving component. We determine a lower limit for the jet/couterjet brightness ratio of 100:1 within 6 mas of the core. We also present a new Very Large Array (VLA) image of the kpc-scale jet with 3 sec resolution, made from data obtained during the VLBI observations. The rate of decrease in jet surface brightness from parsec to kiloparsec scales is similar to jets in known superluminal radio sources.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 427; 1; p. 221-226
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  • 84
    Publikationsdatum: 2011-08-24
    Beschreibung: We compute the three-point temperature correlation function of the Cosmic Background Explorer (COBE) Differential Microwave Radiometer (DMR) first-year sky maps to search for non-Gaussian temperature fluctuations. The level of fluctuations seen in the computed correlation function are too large to be attributable solely to instrument noise. However the fluctuations are consistent with the level expected to result from a superposition of istrument noise and sky signal arising from a Gaussian power-law model of initial fluctuations, with a quadrupole normalized amplitude of 17 micro K and a power-law spectral index n = 1. We place limits on the amplitude of intrinsic three-point correlations with a variety of predicted functional forms.
    Schlagwort(e): ASTROPHYSICS
    Materialart: The Astrophysical Journal, Part 1 (ISSN 0004-637X); 431; 1; p. 1-5
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  • 85
    Publikationsdatum: 2011-08-24
    Beschreibung: The Burst and Transient Source Experiment on the Compton Gamma-Ray Observatory detected 260 cosmic gamma-ray bursts during the period 19 Apr 1991 to 5 Mar 1992. This paper presents the occurrence times, locations, peak count rates, peak fluxes, fluences, durations, and plots of time histories for these bursts. The angular distribution is consistent with isotropy. The intensity distribution shows a deficit in the number of weak bursts, which is not consistent with a homogeneous distribution of burst sources in Euclidean space. The duration distribution shows evidence for a separate class of bursts with durations less than about 2 seconds.
    Schlagwort(e): ASTROPHYSICS
    Materialart: The Astrophysical Journal Supplement Series (ISSN 0067-0049); 92; 1; p. 229-283
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  • 86
    Publikationsdatum: 2011-08-24
    Beschreibung: A simple method for deriving well-behaved temperature solutions to the equation of hydrostatic equilibrium for intracluster media with X-ray imaging observations is presented and applied to a series of generalized models as well as to observations of the Perseus cluster and Abell 2256. In these applications the allowed range in the ratio of nonbaryons to baryons as a function of radius is derived, taking into account the uncertainties and crude spatial resolution of the X-ray spectra and considering a range of physically reasonable mass models with various scale heights. Particular attention is paid to the central regions of the cluster, and it is found that the dark matter can be sufficiently concentrated to be consistent with the high central mass surface densities for moderate-redshift clusters from their gravitational lensing properties.
    Schlagwort(e): ASTROPHYSICS
    Materialart: The Astrophysical Journal, Part 1 (ISSN 0004-637X); 431; 1; p. 91-103
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  • 87
    Publikationsdatum: 2011-08-24
    Beschreibung: Electric dipole transition matrix elements for rovibrational transitions in the X (sup 1)Sigma(sup +) state of the CO minor isotopes (14)C(16)O and (13)C(17)O are calculated for the first time for all the delta v = +1, +2, and +3 transitions for which v less than or equal to 20 and J less than or equal to 150. Improved electric dipole transition matrix elements are also calculated for the minor isotopes (12)C(17)O, (12)C(18)O, (13)C(18)O. We have fitted polynomials to these matrix elements as a function of the parameter m which is defined in terms of the lower state angular momentum quantum number J; the convenient to use polynomial representations are given in tabular form. These results for the minor species of CO complement those previously reported by us for (12)C(16)O and (13)C(16)O.
    Schlagwort(e): ASTROPHYSICS
    Materialart: The Astrophysical Journal Supplement Series (ISSN 0067-0049); 92; 1; p. 311-321
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  • 88
    Publikationsdatum: 2011-08-24
    Beschreibung: Because changes in the Earth's environment have become major global issues, continuous, longterm scientific information is required to assess global problems such as deforestation, desertification, greenhouse effects and climate variations. Global change studies require understanding of interactions of complex processes regulating the Earth system. Space-based Earth observation is an essential element in global change research for documenting changes in Earth environment. It provides synoptic data for conceptual predictive modeling of future environmental change. This paper provides a brief overview of remote sensing technology from the perspective of global change research.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: Geocarto (ISSN 1010-6049); 8; 4; p. 7-18
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  • 89
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    In:  Other Sources
    Publikationsdatum: 2011-08-24
    Beschreibung: We present six ROSAT Position-Sensitive Proportional Counter (PSPC) observations of Seyfert 1 galaxies chosen to have low Galactic line-of-sight absorption (N(sub H) approx. = 10(exp 20)/sq cm). As expected, it is found that all of these sources possess significantly steeper spectra below approximately 1 keV, than that observed at higher X-ray energies. In addition we find evidence for soft X-ray spectral features, which are best parameterized as line emission at approximately 0.63 keV in NGC7469 and approximately 0.75 keV in ESO198-G24. We examine these results in the light of the accuracy of the PSPC spectral calibration. We suggest that Seyfert galaxies are a class of object whose spectra are similar to the diffuse X-ray background in the soft X-ray band. We suggest these data provide the first direct evidence that the sources which dominate the background differ as a function of energy.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Advances in Space Research (ISSN 0273-1177); 13; 12; p. (12)387-(12)390
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  • 90
    Publikationsdatum: 2011-08-24
    Beschreibung: NASA's Cosmic Background Explorer (COBE) carries three scientific instruments to make precise measurements of the spectrum and anisotropy of the cosmic microwave background (CMB) radiation on angular scales greater than 7 deg and to conduct a search for a diffuse cosmic infrared background (CIB) radiation with 0.7 deg angular resolution. Data from the Far-Infrared Absolute Spectrophotometer (FIRAS) show that the spectrum of the CMB is that of a blackbody of temperature T = 2.73 +/- 0.06 K, with no deviation from a blackbody spectrum greater than 0.25% of the peak brightness. The first year of data from the Differential Microwave Radiometers (DMR) show statistically significant CMB anisotropy. The anisotropy is consistent with a scale invariant primordial density fluctuation spectrum. Infrared sky brightness measurements from the Diffuse Infrared Background Experiment (DIRBE) provide new conservative upper limits to the CIB. Extensive modeling of solar system and galactic infrared foregrounds is required for further improvement in the CIB limits.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Advances in Space Research (ISSN 0273-1177); 13; 12; P. (12)409-(12)423
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  • 91
    Publikationsdatum: 2011-08-24
    Beschreibung: We report on the evolution in the X-ray spectrum of the transient X-ray pulsar EXO 2030+375 during part of an outburst in 1985 May-August. The overall continuum spectral shape is similar to that of other accreting pulsars and can be represented by a power-law spectrum modified at low energies by significant absorption and at high-energies either by an exponential cut-off or by the effects of cyclotron scattering. As the luminosity decreased by a factor of approximately 100, the X-ray spectrum became harder with the photon index decreasing from 1.83 +/- 0.01 to 1.29 +/- 0.01. In addition, the high-energy cutoff decreased from 20 to 10 keV during the same interval. If the cutoff is interpreted in terms of cyclotron resonance scattering, then this implies a magnetic field strength that decreased from 2.6 x 10(exp 12) G to 1.3 x 10(exp 12) G. This variation implies that the cutoff energy does not provide a reliable measure of the surface magnetic field strength in this system.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Advances in Space Research (ISSN 0273-1177); 13; 12; p. (12)-355-(12)360
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  • 92
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    In:  Other Sources
    Publikationsdatum: 2011-08-24
    Beschreibung: A more appropriate title for this talk would have been 'Measurements of Large Scale Structure from X-ray Background Fluctuations'. While it has long been recognized that the X-ray Background (XRB) is primarily of a cosmological origin (with z less than a few), it has recently become apparent that surface brightness fluctuations in the surveys of the XRB can be used to trace the distribution of matter in much the same way as complete catalogs of individual objects. The distance which is probed is related to the angular resolution of the detector; for the HEAO-1 A2 experiment, which provides the best all-sky data base for the XRB in the 2-20 keV band, the effective depth is a few 100 Mpc.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Advances in Space Research (ISSN 0273-1177); 13; 12; p. (12)231-(12)240
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  • 93
    Publikationsdatum: 2011-08-24
    Beschreibung: The observational selection bias properties of the large Mathewson-Ford-Buchhorn (MFB) sample of axies are demonstrated by showing that the apparent Hubble constant incorrectly increases outward when determined using Tully-Fisher (TF) photometric distances that are uncorreted for bias. It is further shown that the value of H(sub 0) so determined is also multivlaued at a given redshift when it is calculated by the TF method using galaxies with differenct line widths. The method of removing this unphysical contradiction is developed following the model of the bias set out in Paper II. The model developed further here shows that the appropriate TF magnitude of a galaxy that is drawn from a flux-limited catalog not only is a function of line width but, even in the most idealistic cases, requires a triple-entry correction depending on line width, apparent magnitude, and catalog limit. Using the distance-limited subset of the data, it is shown that the mean intrinsic dispersion of a bias-free TF relation is high. The dispersion depends on line width, decreasing from sigma(M) = 0.7 mag for galaxies with rotational velocities less than 100 km s(exp-1) to sigma(M) = 0.4 mag for galaxies with rotational velocities greater than 250 km s(exp-1). These dispersions are so large that the random errors of the bias-free TF distances are too gross to detect any peculiar motions of individual galaxies, but taken together the data show again the offset of 500 km s(exp-1) fond both by Dressler & Faber and by MFB for galaxies in the direction of the putative Great Attractor but described now in a different way. The maximum amplitude of the bulk streaming motion at the Local Group is approximately 500 km s(exp-1) but the perturbation dies out, approaching the Machian frame defined by the CMB at a distance of approximately 80 Mpc (v is approximately 4000 km s(exp -1)). This decay to zero perturbation at v is approximately 4000 km s(exp -1) argues against existing models with a single attraction at approximately 4500 km s(exp -1) (the Great Attactor model) pulling the local region. Rather, the cause of the perturbation appears to be the well-known clumpy mass distribution within 4000 km s(exp -1) in the busy directions of Hydra, Centaurus, Antila and Dorado, as postulated earlier (Tammann & Sandage 1985).
    Schlagwort(e): ASTROPHYSICS
    Materialart: The Astrophysical Journal, Part 1 (ISSN 0004-637X); 430; 1; p. 29-52
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  • 94
    Publikationsdatum: 2011-08-24
    Beschreibung: Nonthermal radio emission has been observed from some of the most luminous hot star winds. It is understood to be synchrotron radiation of the relativistic electrons in the winds. To understand how the electrons are accelerated to such high energies and to correctly explain the observed radio flux and spectra require an exhaustive investigation of all the relevant physical processes involved and possibly point to a complex wind structure. In this paper we discuss the logical path toward a comprehensive model of the nonthermal radio emission from hot star winds. Based on the available observational data and fundamental theoretical considerations, we found that the only physically viable and self-consistent scenario is: the nonthermal radio emission is synchrotron radiation of relativistic electrons the electrons are accelerated by shocks via the first-order Fermi mechanism the acceleration has to be in situ in the radio emitting region and the shocks formed at the base of the winds have to propagate to beyond the radio photosphere.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysics and Space Science (ISSN 0004-640X); 221; 1-2; p. 259-272
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  • 95
    Publikationsdatum: 2011-08-24
    Beschreibung: Extensive observations of the molecular gas in the young, compact planetary nebula M1-16 have been made, using the Swedish-ESO-Submillimeter Telescope. A map of the CO J = 2-1 emission shows that the molecular envelope contains both a slow and a fast outflow with expansion velocities of 19 km/s and greater than 34 km/s, respectively. The slow outflow is mildly elliptical, while the fast molecular outflow is bipolar. This fast outflow is roughly aligned with the very fast outflows recently found in the optical, while the long axis of the slow elliptical outflow is roughly orthogonal to the optical outflow axis. The kinematic timescales for the CO fast outflow and the optical very fast outflow agree closely, supporting the view that the former represents material in the slow outflow accelerated by the very fast outflow. The kinematic signature of a disk expanding with about 15.5 km/s can also be seen in the CO J = 2-1 data. The mass-loss rate (a) for the slow outflow is greater than or equal to 2.8 x 10(exp -5) solar mass/yr and possibly as large as 9 x 10(exp -5) solar mass/yr, (b) for the fast outflow is greater than or equal to 5 x 10(exp -6) solar mass/yr, and (c) for the very fast optically visible outflow is approximately equal 5 x 10(exp -7) solar mass/yr. The disk mass is approximately equal 6 x 10(exp -3) solar mass. Grain photoelectric heating results in temperatures of 20-70 K in molecular gas of the slow outflow. The (13)C/(12)C abundance ratio in M1-16 is found to be 0.33, quite possibly the highest found for any evolved object. Upper limits for the (18)O/(16)O and (17)O/(16)O ratios were found to be consistent with the values found in AGB stars. A search for other molecular species in M1-16 resulted in the detection of the high-excitation species HCN, CN, (13)CN, HCO(+), and H(13)CO(+) and possibly N2H(+). Both the HCO(+)/HCN and CN/HCN line-intensity ratios are enhanced, the former by a very large factor, over the values found in the envelopes of AGB stars, probably as a result of enhancement of the CN and HCO(+) abundances due to photochemistry induced by the stellar UV. The CS J = 2-1, SiO J = 2-1 (v = 0), and SiS J = 6-5 lines were not detected to low levels. For the high-excitation molecules, adequate collisional excitation of rotational levels and survival against photodissociation by the UV radiation requires significant clumping of the molecular gas into clumps with H2 densities approximately 10(exp 5)/cu cm. The IRAS fluxes of M1-16, assuming negligible contribution from line emission, imply the presence of about (1.7-0.4) x 10(exp -3) solar mass of cool dust (temperature around 50 K) and a smaller quantity, (2.7-3.1) x 10(exp -6) solar mass, of warmer dust (temperature around 125 K) for a power-law emissivity index p = 1-2. The evolutionary nature of M1-16 cannot be explained by existing single-star models of post-AGB evolution. The very high (13)C/(12)C abundance ratio in M1-16 suggests a possible evolutionary connection between M1-16 and the rare class of J-type silicate-carbon stars which also have high (13)C/(12)C ratios and are thought to be binary systems with accretion disks.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 428; 1; p. 237-249
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  • 96
    Publikationsdatum: 2011-08-24
    Beschreibung: We have observed the C91 alpha radio recombination line toward the Orion H II region. This narrow (approximately 3-5 km per sec full width at half maximum (FWHM)) line is spatially very extended (approximately 8 arcmin or 1 pc). These charateristics compare well with the observed characteristics of the C II fine structure line at 158 microns. Thus, the C91 alpha line originates in the predominantly neutral photodissociation regions separating the H II region from the molecular cloud. We have developed theoretical models for the C II radio recombination lines from photodissociation regions. The results show that the I(C91 alpha)/I(C158) intensity ratio is a sensitive function of the temperature and density of the emitting gas. We have also extended theoretical models for photodissociation regions to include the C II recombination lines. Comparison with these models show that, in the central portion of the Orion region, the C91 alpha line originates in dense (10(exp 6) per cu cm), warm (500-1000 K) gas. Even at large projected distances (approximately 1 pc), the inferred density is still high (10(exp 5) per cu cm) and implies extremely high thermal pressures. As in the case of the (C II) 158 microns line, the large extent of the C91 alpha line shows that (FUV) photons can penetrate to large distances from the illuminating source. The decline of the intensity of the incident radiation field with distance from Theta(sup 1) C seems to be dominated by geometrical dilution, rather than dust extinction. Finally, we have used our models to calculate the intensity of the 9850 A recombination line of C II. The physical conditions inferred from this line are in good agreement with those determined from the radio recombination and the far-infrared fine-structure lines. We show that the ratio of the 9850 A to the C91 alpha lines is a very good probe of very high density clumps.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 428; 1; p. 209-218
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  • 97
    Publikationsdatum: 2011-08-24
    Beschreibung: Statistical uncertainties in determining the temperatures of hot (0.5-10 keV) coronal plasmas are investigated. The statistical presicion of various spectral temperature diagnostics is established by analyzing synthetic ASCA solid-state imaging spectrometer (SIS) CCD spectra. The diagnostics considered are the ratio of hydrogen-like to helium-like line complexes of Z greater than or = 14 elements, line-free portions of the continuum, and the entire spectrum. While fits to the entire spectrum yield the highest statistical precision, it is argued that fits to the line-free continuum are less susceptible to atomic data uncertainties but lead to a modest increase in statistical uncertainty over full spectral fits. Temperatures deduced from line ratios can have similar accuracy, but only over a narrow range of temperatures. Convenient estimates of statistical accuracies for the various temperature diagnostics are provided which may be used in planning ASCA SIS observations.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X); 435; 2; p. L149-L152
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  • 98
    Publikationsdatum: 2011-08-24
    Beschreibung: The shape of the velocity distribution of water group ions observed by the Giotto ion mass spectrometer on its approach to comet Halley is modeled to derive empirical values for the rates of ionization, energy diffusion, and loss in the midcometosheath. The model includes the effect of rapid pitch angle scattering into a bispherical shell distribution as well as the effect of the magnetization of the plasma on the charge exchange loss rate. It is found that the average rate of ionization of cometary neutrals in this region of the cometosheath appears to be of the order of a factor 3 faster than the `standard' rates approx. 1 x 10(exp -6)/s that are generally assumed to model the observations in most regions of the comet environment. For the region of the coma studied in the present work (approx. 1 - 2 x 10(exp 5) km from the nucleus), the inferred energy diffusion coefficient is D(sub 0) approx. equals 0.0002 to 0.0005 sq km/cu s, which is generally lower than values used in other models. The empirically obtained loss rate appears to be about an order of magnitude greater than can be explained by charge exchange with the `standard' cross section of approx. 2 x 10(exp -15)sq cm. However such cross sections are not well known and for water group ion/water group neutral interactions, rates as high as 8 x 10(exp -15) sq cm have previously been suggested in the literature. Assuming the entire loss rate is due to charge exchange yields a rate of creation of fast neutral atoms of the order of approx. 10(exp -4)/s or higher, depending on the level of velocity diffusion. The fast neutrals may, in turn, be partly responsible for the higher-than-expected ionization rate.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Journal of Geophysical Research (ISSN 0148-0227); 99; A10; p. 19,245-19,254
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  • 99
    Publikationsdatum: 2011-08-24
    Beschreibung: HH 80-81 are two optically visible Herbig-Haro (HH) objects located about 5 minutes south of their exciting source IRAS 18162-2048. Displaced symmetrically to the north of this luminous IRAS source, a possible HH counterpart was recently detected as a radio continuum source with the very large array (VLA). This radio source, HH 80 North, has been proposed to be a member of the Herbig-Haro class since its centimeter flux density, angular size, spectral index, and morphology are all similar to those of HH 80. However, no object has been detected at optical wavelengths at the position of HH 80 North, possibly because of high extinction, and the confirmation of the radio continuum source as an HH object has not been possible. In the prototypical Herbig-Haro objects HH 1 and 2, ammonia emission has been detected downstream of the flow in both objects. This detection has been intepreted as a result of an enhancement in the ammonia emission produced by the radiation field of the shock associated with the HH object. In this Letter we report the detection of the (1,1) and (2,2) inversion transitions of ammonia downstream HH 80 North. This detection gives strong suppport to the interpretation of HH 80 North as a heavily obscured HH object. In addition, we suggest that ammonia emission may be a tracer of embedded Herbig-Haro objects in other regions of star formation. A 60 micrometer IRAS source could be associated with HH 80 North and with the ammonia condensation. A tentative explanation for the far-infrared emission as arising in dust heated by their optical and UV radiation of the HH object is presented.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X); 435; 2; p. L145-L148
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  • 100
    Publikationsdatum: 2011-08-24
    Beschreibung: The Giotto ion mass spectrometer high-intensity spectrometer (IMS-HIS) measured fluxes of ions from about 260,000 km before (1008:37 UT spacecraft time) to about 86,000 km after (1701:33 UT spacecraft time) closest approach to comet P/Grigg-Skjellerup during the encounter on July 10, 1992. Although the HIS sensor was not designed to measure protons, these ions were measured far from the comet. Close in to the comet, the ions observed were probably also protons, although heavier ions cannot be completely ruled out. Considerable temporal structure appears in the data, well-correlated with the data of other instruments onboard, especially those of the magnetometer. In particular, the ion count rate correlates with the direction of the magnetic field. This strong modulation at the water group ion cyclotron period (approx. 90 s) inside the inbound bow wave indicates a very narrow ion pitch angle distribution. Hence at Grigg-Skjellerup the ions appear to experience very little pitch angle scattering. This may result from strong compression in the rapidly increasing magnetic field.
    Schlagwort(e): ASTROPHYSICS
    Materialart: Journal of Geophysical Research (ISSN 0148-0227); 99; A10; p. 19,255-19,265
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