ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Active and passive microwave measurements of soil moisture in FIFE (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: During the intensive field campaigns of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) in May-October of 1987, several nearly simultaneous measurements were made with low-altitude flights of the L-band radiometer and C- and X-band scatterometers over two transects in the Konza Prairie Natural Research Area, some 8 km south of Manhattan, Kansas. These measurements showed that although the scatterometers were sensitive to soil moisture variations in most regions under the flight path, the L-band radiometer lost most of its sensitivity in regions unburned for many years. The correlation coefficient derived from the regression between the radar backscattering coefficient and the soil moisture was found to improve with the increase in antenna incidence angle. This is attributed to a steeper falloff of the backscattering coefficient as a function of local incidence at angles near nadir than at angles greater than 30 deg.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Journal of Geophysical Research (ISSN 0148-0227); 97; D17; p. 18,979-18,985.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Comparison of measurements and theory for backscatter from vegetation-covered soil on the Konza prairie (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: Radar backscatter measurements over the Konza Prairie were obtained by means of C- and X-band scatterometers as a part of the first ISLSCP Field Experiment (FIFE) to determine soil moisture. Nearly simultaneous radar and radiometer data sets were collected along two transects that coincided with direct soil-moisture measurements. The results show that radars can be used for soil-moisture estimation over the complete transect, whereas radiometer sensitivity to soil moisture is drastically reduced over regions left unburned for many years. A combined rough-surface/volume scatter model was formulated. Calculated and measured scattering data are compared to determine the sensitivity of the scattering coefficient to different surface treatments.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: In: IGARSS '92; Proceedings of the 12th Annual International Geoscience and Remote Sensing Symposium, Houston, TX, May 26-29, 1992. Vol. 2 (A93-47551 20-43); p. 920-922.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Terrain effects on backscattering coefficients derived from multifrequency, polarimetric SAR data (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: A set of multidate, multilook angle polarimetric SAR data, acquired in Pennsylvania during July 1990 was recorded to determine the effect of local incidence angle. Cosine-based and polynomial models are found to be equally good for correcting SAR data for local incidence angle effects. A modified approach, considering the correction factor as additive rather than multiplicative, gave better results. The standard error in the estimation of soil moisture improves from 8.1 to 5.8 after applying corrections to incidence angle effects.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: In: IGARSS '92; Proceedings of the 12th Annual International Geoscience and Remote Sensing Symposium, Houston, TX, May 26-29, 1992. Vol. 1 (A93-47551 20-43); p. 86-88.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Passive microwave remote sensing of soil moisture - Results from HAPEX, FIFE and MONSOON 90 (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: HAPEX (Hydrologic Atmospheric Pilot Experiment), FIFE (First ISLSCP Field Experiment) and MONSOON 90 which used an imaging microwave radiometer operating at a frequency of 1.42 GHz are reported. For FIFE and MONSOON 90, a wide range of moisture conditions were present and it was possible to observe the drydown of the soil following heavy rain and to map its spatial variation. The quantitative agreement of microwave observations and ground measurements was very good. In HAPEX there were no significant rains and conditions were generally rather dry, however, moisture variations due to irrigation were observed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: ISPRS Journal of Photogrammetry and Remote Sensing (ISSN 0924-2716); 47; 2-3,; 127-143
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    An overview of the measurements of soil moisture and modeling of moisture flux in FIFE (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: Measurements of soil moisture and calculations of moisture transfer in the soil medium and at the air-soil interface were performed over a 15-km by 15-km test site during FIFE in 1987 and 1989. The measurements included intensive soil moisture sampling at the ground level and surveys at aircraft altitudes by several passive and active microwave sensors as well as a gamma radiation device.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: Journal of Geophysical Research (ISSN 0148-0227); 97; D17; p. 18,955-18,959.
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Experiment design and operations (1990)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The objectives, design, and field operations of the First ISLSCP Field Experiment (FIFE) are described. The simultaneous acquisition of satellite, atmosphere, and surface data, and the understanding of the processes governing surface energy and mass exchange and how these are manifested in satellite-resolution radiometric data are identified as the specific objectives of the field-phase experiment. The central issues concerning the design of the field experiment are considered: the size of the site, the duration of the experiment, and the location of the site; it is noted that the Konza Prairie National Reserve was selected as the focus of the study. Field operations in 1987 and 1989 are discussed, and it is pointed out that a data set is available now from a single combined repository to all FIFE investigators, and that scientists can test models and algorithms on scales consistent with satellite observations and with enough supporting data on finer scales.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Simulated and observed 37 GHz emission over Africa (1990)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A model for simulating polarized 37-GHz microwave emissions from vegetated surfaces is proposed. An equation expressing the radiative transfer is solved using a two-point Gauss quadrature method. Surface temperature, reflectance, normalized difference, and polarized brightness temperatures are obtained from processed multispectral satellite data. The model simulations are evaluated against satellite data collected between January 1982 and December 1983 along a transect going from rain forest to hot desert over Africa (0 deg to 20 deg N, 11 deg E). It is found that the temporal variation of the average brightness temperature matches closely the surface temperature. The seasonal variation of the polarization difference is confined within the latitude band of 8 deg to 18 deg N, but the normalized difference continues to show seasonal variation south of 8 deg N. The relations between the polarization difference and the normal difference and between the polarization difference and the reflectance are considered to be nonlinear and almost linear, respectively.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: International Journal of Remote Sensing (ISSN 0143-1161); 11; 1837-186
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    The SIR-B observations of microwave backscatter dependence on soil moisture, surface roughness, and vegetation covers (1986)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: An experiment was conducted from an L-band SAR aboard Space Shuttle Challenger in October 1984 to study the microwave backscatter dependence on soil moisture, surface roughness, and vegetation cover. The results based on the analyses of an image obtained at 21-deg incidence angle show a positive correlatlion between scattering coefficient and soil moisture content, with a sensitivity comparable to that derived from the ground radar measurements reported by Ulaby et al. (1978). The surface roughness strongly affects the microwave backscatter. A factor of two change in the standard deviation of surface roughness height gives a corresponding change of about 8 dB in the scattering coefficient. The microwave backscatter also depends on the vegetation types. Under the dry soil conditions, the scattering coefficient is observed to change from about -24 dB for an alfalfa or lettuce field to about -17 dB for a mature corn field. These results suggest that observations with a SAR system of multiple frequencies and polarizations are required to unravel the effects of soil moisture, surface roughness, and vegetation cover.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); GE-24; 510-516
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    Results from the pushbroom microwave radiometer flights over the Konza Prairie in 1985 (1987)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Four flights were conducted by the NASA C-130 aircraft sensor platform bearing the 'pushbroom' microwave radiometer (PBMR) over the Konza Prairie in central Kansas in 1985, in order to monitor soil surface variations. When the brightness temperature maps thus obtained were analyzed, a striking difference was noted between burned and unburned watersheds; the latter had a very high emissivity despite having saturated soils, while the former had low values that increased with the gradual drying of the soils. The lack of sensitivity for the unburned watershed is tentatively attributed to the build-up of a thatch layer by the decaying vegetation, which serves as a good microwave absorber when wet.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    Roughness measurements with multipolarization aircraft data (1987)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: Multipolarization SAR data were collected over the SIR-B target area near Fresno, California, a few days before the Shuttle flight. Attempts to use these data to evaluate roughness models were unsuccessful. It is speculated that the processing of those data to give good total swath and target contrast resulted in very little variation among the bare fields. Special processing to provide adequate contrast among the targets of interest and to account for a large incidence angle variation may be necessary to make these data useful for this type of study.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...