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  • Other Sources  (1,740)
  • METEOROLOGY AND CLIMATOLOGY  (700)
  • SOLAR PHYSICS  (589)
  • COMMUNICATIONS AND RADAR  (451)
  • 1980-1984  (1,740)
  • 1983  (915)
  • 1981  (825)
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  • Other Sources  (1,740)
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  • 1980-1984  (1,740)
Year
  • 1
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    Joint Airport Weather Studies (AWS) project (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The joint airport weather studies (JAWS) project is discussed. The major objectives of the JAWS Project are a fundamental description of the phenomenon, a determination of the hazard potential and a definition of a protection and warning system, all of which are relative to low level wind shear. Aspects of the low level wind shear phenomenon. The principal focus, however, is the microburst. The microburst is fundamentally a rather simple atmospheric flow. It is a downdraft that, upon approaching the surface, spreads out horizontally, producing a diverging radial flow in all directions. For any direction that an aircraft flies through the microburst, it will first encounter increasing head winds; then the remnants of the downdraft; and then, increasing tail wind.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 85-95
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  • 2
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    Lightning strike experience in the NASA F-106B storm hazards program (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A heavily instrumented F-106B aircraft was flown in thunderstorms to gather data for characterizing lightning at aircraft operating altitudes. Conventional weather finding techniques are supplemented with UHF lightning mapping radar to select the most active storm cells and the most likely altitude for obtaining direct lightning strikes to the airplane. One hundred seventy-six strikes were obtained in a 3 year period, mostly at an altitude of above 25,000 feet.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 63-65
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  • 3
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    Wind shear and vortex wake research in UK, 1982 (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A wind shear and vortex wake and their impact on aircraft were investigated. The systems and advice to help pilots, and rational scientific methods to assist in advising certification authorities and those interested in improving flight safety were developed. Wind Shear and Vortex Wakes are related, they are both invisible enemies of aircraft in the form of large disturbances in the atmosphere, both cause major accidents. Problems of building wakes at airports are is considered. Research on wind shear was initiated by the American FAA following the Boston, New York and Denver accidents to civil airliners. This resulted in: useful advice to pilots about wind shear; better attempts by the meteorologists at forecasting wind shear conditions; and useful ideas for wind shear measurement and warning systems. Three major research tasks are outstanding: (1) Worldwide measurements to give reliable estimates of probability and details of the forms of large wind shears; (2) Developments of real time wind shear measuring systems for ground or airborne use; and (3) Establishing relationships between measured wind shear and the potential hazard to an aircraft, or class of aircraft.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 66-83
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  • 4
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    Marked surface inversions and wind shear: A safety risk for departing aircraft (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Marked surface inversions occur most frequently in dry continental climates, where low atmospheric humidity allows heat transfer by long wave thermal radiation. In the northern latitudes, surface inversions reach their maximum intensity during the winter, when the incoming Sun's radiation is negligible and radiative cooling is dominant during the long nights. During winter, air mass boundaries are sharp, which causes formation of marked surface inversions. The existence of these inversions and sharp boundaries increase the risk of wind shear. The information should refer to marked inversions exceeding a temperature difference of 10 deg C up to 1000 feet. The need to determine the temperature range over which he information is operationally needed and the magnitude of the inversion required before a notification to pilots prior to departure is warranted are outlined.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 61-62
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  • 5
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    A cursory glance at results from NASA's B-57B gust gradient program (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The Gust Gradient Program is a data intensive effort involving tripple Doppler radar, a surface weather station mesonet and other aircraft. The Joint Airport Weather Studies was utilized to gain additional data. The data were used to fill in the gap in turbulence modeling.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 38-42
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  • 6
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    GEM: Statistical weather forecasting procedure (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The objective of the Generalized Exponential Markov (GEM) Program was to develop a weather forecast guidance system that would: predict between 0 to 6 hours all elements in the airways observations; respond instantly to the latest observed conditions of the surface weather; process these observations at local sites on minicomputing equipment; exceed the accuracy of current persistence predictions at the shortest prediction of one hour and beyond; exceed the accuracy of current forecast model output statistics inside eight hours; and be capable of making predictions at one location for all locations where weather information is available.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 42-44
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  • 7
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    Department of Defense meteorological and environmental inputs to aviation systems (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Recommendations based on need, cost, and achievement of flight safety are offered, and the re-evaluation of weather parameters needed for safe landing operations that lead to reliable and consistent automated observation capabilities are considered.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 19-20
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  • 8
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    Aviation weather services (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The primary responsibilities of the National Weather Service (NWS) are to: provide warnings of severe weather and flooding for the protection of life and property; provide public forecasts for land and adjacent ocean areas for planning and operation; and provide weather support for: production of food and fiber; management of water resources; production, distribution and use of energy; and efficient and safe air operations.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 14-16
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  • 9
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    Federal Aviation Administration weather program to improve aviation safety (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The implementation of the National Airspace System (NAS) will improve safety services to aviation. These services include collision avoidance, improved landing systems and better weather data acquisition and dissemination. The program to improve the quality of weather information includes the following: Radar Remote Weather Display System; Flight Service Automation System; Automatic Weather Observation System; Center Weather Processor, and Next Generation Weather Radar Development.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 21-25
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  • 10
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    On the effect of temporal sampling on the observation of mean rainfall (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Rainfall characteristics using data from dense recording raingage networks is reviewed. Data from such networks have quantified temporal and spatial rainfall distributions, and have supplied specialized information about local and orographic effects. The natural variability, temporally and spatially, for annual, seasonal, monthly, and individual events is treated. Especially important are the spatial variations of precipitation as a function of synoptic type, precipitation type, amount, and duration. Results from dense raingage networks in Illinois, and some data from other climatic regions is also treated.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Precipitation Meas. from Space:; 8 p
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  • 11
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    Prospects for measuring phytoplankton bloom extent and patchiness using remotely sensed color images: An example (1981)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: A 10 channel scanning radiometer, built as a prototype for the coastal zone color scanner on the Nimbus 7 satellite, was flown on a high altitude aircraft during a Gymnodium breve bloom along the west coast of Florida. The remotely measured ocean color imagery shows what is probably the patchy structure of a G. breve bloom extending over a 60 km by 100 km area. This conclusion is based on visual inspection of bathymetry to infer bottom reflection trends and on a single growth truth measurement of B G. breve obtained the previous day. The image shows coherent blooms which extend scales up to 60 km in length.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Goddard Lab. for Atmospheric Sci., Collected Reprints 1978 - 1979, Vol. 2; p 680-685
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  • 12
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    Arctic Sea ice decay simulated for a CO2-induced temperature rise (1981)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: A large scale numerical time-dependent model of sea ice that takes into account the heat fluxes in and out of the ice, the seasonal occurrence of snow, and ice motions was used in an experiment to determine the response of the Arctic Ocean ice pack to a warming of the atmosphere. The degree of warming specified is that expected for a doubling of atmospheric carbon dioxide with its associated greenhouse effect, a condition that could occur before the middle of the next century. The results of three 5-year simulations with a warmer atmosphere and varied boundary conditions were: (1) that in the face of a 5 K surface atmospheric temperature increase the ice pack disappeared completely in August and September but reformed in the central Arctic Ocean in mid fall; (2) that the simulations were moderately dependence on assumptions concerning cloud cover; and (3) that even when atmospheric temperature increases of 6-9 K were combined with an order-of-magnitude increase in the upward heat flux from the ocean, the ice still appeared in winter. It should be noted that a year-round ice-free Arctic Ocean has apparently not existed for a million years or more.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Goddard Lab. for Atmospheric Sci., Collected Reprints 1978 - 1979, Vol. 2; p 687-700
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  • 13
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    The 1977 tundra fire at Kokolik River, Alaska (1981)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: During the summer of 1977, fire totaled 44 sq km of tundra vegetation according to measurements using LANDSAT imagery. Based on the experience gained from analysis of this fire using ground observations, satellite imagery, and topographic maps, it appears that natural drainages form effective fire breaks on the subdued relief of the Arctic coastal plain and northern foothills. It is confirmed that the intensity of the fire is related to vegetation type and to the moisture content of the organic rich soils.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Goddard Lab. for Atmospheric Sci., Collected Reprints 1978 - 1979, Vol. 2; p 660-670
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  • 14
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    The 1977 tundra fire in the Kokolik River area of Alaska (1981)
    In:  CASI
    Details
    Publication Date: 2006-04-26
    Description: Presumably caused by lightning, a large fire occurred due east of Point Lay several kilometers southwest of the Kokolik River, the farthest north a fire was ever fought by Bureau of Land Management personnel in Alaska. The progress and area extent of the fire were determined by analysis of LANDSAT MSS band 5 and 7 imagery. Low altitude observations from helicopter showed the fire burned a range of vegetation and relief types which included low polygonized and upland tussock tundras. The burned area appeared wetter on the surface than the unburned area, due to a lack of moisture absorbing organic matter and the possible release of moisture from the deeper thawed zone. Suggestions for future investigations of the effects of fire on tundra and permafrost terrains are discussed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Goddard Lab. for Atmospheric Sci., Collected Reprints 1978 - 1979, Vol. 2; p 671-675
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  • 15
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    Measurement of the solar constant (1981)
    In:  CASI
    Details
    Publication Date: 2006-06-04
    Description: The absolute value of the solar constant and the long term variations that exist in the absolute value of the solar constant were measured. The solar constant is the total irradiance of the Sun at a distance of one astronomical unit. An absolute radiometer removed from the effects of the atmosphere with its calibration tested in situ was used to measure the solar constant. The importance of an accurate knowledge of the solar constant is emphasized.
    Keywords: SOLAR PHYSICS
    Type: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 16
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    Solar spectrum from 170 to 3200 nanometers (1981)
    In:  CASI
    Details
    Publication Date: 2006-06-04
    Description: The spectral irradiance of the Sun between 170 and 3200 nanometers was measured to determine accurately the solar constant, its possible variation with the solar cycle, and the wavelength range responsible for the observed variations. It is pointed out that measurements over very long time periods (10 years) involving flights of the same instrument on future Spacelab missions will be required. Few spectral solar irradiation measurements ranging from the near ultraviolet to the near infrared have been performed yet. The most extensive solar irradiation measurements were obtained by a spectrometer onboard an aircraft or from high altitude observatories. The full disk irradiation flux was measured, corrections for atmospheric absorption are applied in all of the measurements.
    Keywords: SOLAR PHYSICS
    Type: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 17
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    Prediction techniques (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Prediction methods and related propagation results for the evaluation of Earth-space communication paths operating above 10 GHz are presented. Gaseous attenuation, rain, cloud, fog, sand, and dust attenuation, path diversity, signal fluctuations and low angle fading, depolarization effects, bandwidth coherence, and sky noise are considered.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Propagation Effects Handbook for Satellite Systems Design; p 195-348
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  • 18
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    Characteristics of rain and rain systems (1981)
    In:  CASI
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    Publication Date: 2006-02-14
    Description: The description and measurement of the macroscopic and microscopic characteristics of rain and rain systems are discussed. The statistical relationships of these characteristics and their effect on polarization and attenuation are considered. Macroscopic characteristics include the size, distribution, and movements of rain cells, the height of melting layers, and the presence of ice crystals. Microscopic characteristics include the size distribution, density, and oblateness of rain drops and ice crystals. The estimation of a major propagation effect, specific attenuation, is described.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Propagation Effects Handbook for Satellite Systems Design; p 5-39
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  • 19
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    The Joint Airport Weather Studies Project (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A block diagram of the joint airport weather studies program is presented. Background leading to the development of the program is reviewed. Basic studies, aircraft performance, and detection and warning techniques used to develop fine scale structure of thunderstorm dynamics and kinematics in the vicinity of a major airport; effect of thunderstorm low level wind shear on aircraft performance; and development of real time testing of flow level wind shear detection and warning techniques and displays are described.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 5th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 91-95
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  • 20
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    Prototype Regional Observation and Forecast System (PROFS) (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The prototype regional observation and forecast system (PROFS) outputs are demonstrated, functional design specifications to be used to procure and implement operational systems are outlined. Advanced candidate technologies are evaluated as an integral part of the process that leads to these outputs. Evaluation insures that future weather service systems will contain the optimum mix of technologies to be most cost effective in reducing the annual losses and deaths that are directly attributed to severe weather.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 5th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 81-85
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  • 21
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    Progress on low altitude cloud icing research (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The icing environment at altitudes below 10,000 feet were studied. The following questions are asked, are: (1) existing aircraft certification criteria applicable; (2) too stringent on icing for helos; (3) based on accurate data; (4) appropriate for low (10,000 ft) altitudes? The research plan is outlined: review historical icing data, obtain new measurements, collect modern icing data from other groups, and recommend LWC, OAT, and MVD criteria for helicopters. Estimated accuracies and known sources of error are included. It is concluded that the net effect of possible sources of error of both signs is uncertain.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 5th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 59-63
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  • 22
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    Propagation data bases (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Existing data bases accumulated as the result of experiments to gather propagation data on millimeter wave Earth-space links are described. The satellites used are described and results of the significant experiments conducted in the United States are summarized. The data bases consist primarily of cumulative attenuation statistics, though some depolarization measurements are included. Additional summaries of propagation data are cited.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Its Propagation Effects Handbook for Satellite Systems Design; p 155-194
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  • 23
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    An overview of several rain and attenuation models (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The key features of the Rice-Holmberg, Dutton-Dougherty, Global, Lin, and Piecewise Uniform Rain Rate models for estimation of cumulative attenuation statistics on Earth-space millimeter paths are summarized. The models provide either rain rate statistics or attenuation statistics, which can be related by use of the specific attenuation and the effective path length relation. The effective path length is defined. The advantages and disadvantages of each model for specific applications are discussed. The Global model is recommended as the design tool for predicting propagation effects in Earth-space communication systems.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Propagation Effects Handbook for Satellite Systems Design; p 41-101
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  • 24
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    Application of propagation predictions to Earth/space telecommunications system design (1981)
    In:  CASI
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    Publication Date: 2006-02-14
    Description: The corresponding between a given propagation phenomenon and system performance is considered. Propagation data are related to system performance parameters, allowing the systems engineer to perform the analyses determining how well requirements are met by a given system design, and enabling the systems engineer to modify that design if necessary. The various ways of specifying performance criteria for different kinds of systems are discussed, and a general procedure for system design is presented and demonstrated.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Propagation Effects Handbook for Satellite Systems Design; p 349-404
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  • 25
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    Depolarization on Earth-space paths (1981)
    In:  CASI
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    Publication Date: 2006-02-14
    Description: Sources of depolarization effects on the propagation paths of orthogonally-polarized information channels are considered. The main sources of depolarization at millimeter wave frequencies are hydrometeor absorption and scattering in the troposphere. Terms are defined. Mathematical formulations for the effects of the propagation medium characteristics and antenna performance on signals in dual polarization Earth-space links are presented. Techniques for modeling rain and ice depolarization are discussed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Propagation Effects Handbook for Satellite Systems Design; p 103-154
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  • 26
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    Some experiments on the effect of remote sounding temperatures upon weather forecasting (1981)
    In:  CASI
    Details
    Publication Date: 2006-03-27
    Description: A time-continuous statistical method is presented for the four dimensional assimilation of remote sounding temperatures based on radiance measurements from polar orbiting satellites. This method is applied to DST 6 data from the NOAA 4 and Nimbus 6 satellites. The state of the atmosphere throughout the test period was determined using a varying amount of satellite data from the NOAA 4 satellite only, from Nimbus 6 only, and from both satellites together. The methods tested included different variations of the statistical method, as well as more traditional methods. It is concluded that satellite derived temperature data can have a modest, but statistically significant positive impact on numerical weather prediction in the two to three day range, and that this impact is highly sensitive to the quantity of data available and to the assimilation method used.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Goddard Lab. for Atmospheric Sci., Collected Reprints, 1978 - 1979, Vol. 1; p 175-199
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  • 27
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    Report on the Workshop on Intercomparison of Solar UV Irradiance Measurements and Related Instrument Calibration (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The knowledge of the absolute value of the solar ultraviolet irradiance did not improve very much during the rising phase of the solar cycle 21. The variations associated with the solar rotation period were observed by means of three satellites, namely, the Atmospheric Explorer E (AE-E), Nimbus 7 and the Solar Mesospheric Explorer (SME). Long-term variations related to the solar activity cycle are not well known. Values were deduced during the solar cycle 21 from the AE-E satellite and the rocket program performed by the Laboratory for Atmospheric and Space Physics leading to variations of about a factor of 2 around 150 nm but definitely less than 20 percent beyond 175 nm. Such low level of variation is still masked by the current uncertainties and reproducibility of the observations performed since 1976. The uncertainties of recent observations are reported with their discrepancies. The gaps between the current accuracy goals and the achievements are still very important. The challenge for the next three years is to improve both the accuracy and the precision of future observations at the level of the available irradiance standards and to measure quantitatively long-term variations of the order of a few percent. The main causes of these gaps are identified.
    Keywords: SOLAR PHYSICS
    Type: International Council of Scientific Unions Middle Atmosphere Program. Handbook for MAP, Vol. 8; p 45-51
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  • 28
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    Atmospheric attenuation for correlated satellite communication ground sites (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Link margin estimates are calculated for 30/20 GHz satellite communication systems employing closely-spaced (4 to 100 km) 'dual diversity' switched ground sites. The link margin estimates are based on a new analysis in which the bivariate rain attenuation density function for two correlated ground sites is modelled by an exponential density function. The results of the exponential density function analysis enable derivation of a direct relation between rain margin estimates and probability of exceedance (link availability). Margins typically in the range 2 to 12 dB are calculated for various ground site separations and summarized for seven city locations and five satellite orbit positions over the U.S. The results can be easily extended to other EHF satellite frequencies and other locations.
    Keywords: COMMUNICATIONS AND RADAR
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  • 29
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    Effects of ISI and satellite channel nonlinearity on Viterbi demodulation/decoding (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is shown that, for convolutionally coded transmission over bandwidth-constrained channels, a mere reversal of the switching direction at the encoder output produces a change in the system bit error probability performance. This change is significant when the Viterbi demodulator/decoder is matched to the total channel memory and is more significant for linear channels than for nonlinear ones. The reversal of switching direction is a simple demonstration of the fact that the well-known optimum codes for the linear AGWN channel are no longer necessarily optimum for a bandwidth-constrained channel with or without the addition of channel nonlinearity. It is concluded that potentially significant performance improvement can be obtained by matching the encoder (through the appropriate choice of tap weights and modulo-2 summers) to the channel in addition to matching the demodulator/decoder to the channel for a given encoder.
    Keywords: COMMUNICATIONS AND RADAR
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  • 30
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    Electrodynamic coupling in magnetically confined stellar X-ray loops (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The solar coronal complex X-ray structure is now known to involve radiation loops that coincide spatially with the magnetic loops confining the radiating plasma. An effort is presently made to identify primary submodels involved in the global coupling between a mechanical energy reservoir of beta value greater than 1 and a contiguous site of X-ray activity whose beta value is lower than 1. The 'dynamo' model invoked establishes a quantitative connection between mechanical driver properties and the dimensions, field strength, and number density distribution of elemental magnetic loops.
    Keywords: SOLAR PHYSICS
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  • 31
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    A case study of the sensitivity of forecast skill to data and data analysis techniques (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: A series of experiments have been conducted to examine the sensitivity of forecast skill to various data and data analysis techniques for the 0000 GMT case of January 21, 1979. These include the individual components of the FGGE observing system, the temperatures obtained with different satellite retrieval methods, and the method of vertical interpolation between the mandatory pressure analysis levels and the model sigma levels. It is found that NESS TIROS-N infrared retrievals seriously degrade a rawinsonde-only analysis over land, resulting in a poorer forecast over North America. Less degradation in the 72-hr forecast skill at sea level and some improvement at 500 mb is noted, relative to the control with TIROS-N retrievals produced with a physical inversion method which utilizes a 6-hr forecast first guess. NESS VTPR oceanic retrievals lead to an improved forecast over North America when added to the control.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    Effect of high latitude filtering on NWP skill (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An assessment is made of the extent to which polar filtering may seriously affect the skill of latitude-longitude NWP models, such as the U.S. Navy's NOGAPS, or the GLAS fourth-order model. The limited experiments which have been completed to date with the 4 x 5-deg, 9-level version of the latter model indicate that the high latitude filter currently in operation affects its forecasting skill very little, with only one exception in which the use of the PG filter significantly improved forecasting.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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  • 33
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    Thunderstorm cloud top observations using satellite stereoscopy (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The present investigation has as objective to take a detailed look at the intense squall line over Oklahoma on May 2-3, 1979, using GOES stereoscopy combined with GOES infrared data. The synoptic situation and data sources are considered along with the stereoscopically observed cloud top ascent rates. Cloud top observations of intense thunderstorms are discussed, taking into account a contouring technique, the interpretation of infrared cloud top temperature patterns, and small-scale structure and its variability. It is found that GOES IR cloud top temperatures grossly underestimate the actual cloud top height observed stereoscopically, especially for immature storms. It is difficult to define growing storms below about 10 km in the GOES infrared data.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; 1949-196
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  • 34
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    Transport and the seasonal variation of ozone (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The transport mechanisms responsible for the seasonal behavior of total ozone are deduced from the comparison of model results to stratospheric data. The seasonal transport is dominated by a combination of the diabatic circulation and transient planetary wave activity acting on a diffusively and photochemically determined background state. The seasonal variation is not correctly modeled as a diffusive process. The buildup of total ozone at high latitudes during winter is dependent upon transient planetary wave activity of sufficient strength to cause the breakdown of the polar vortex. While midwinter warmings are responsible for enhanced ozone transport to high latitudes, the final warming marking the transition from zonal mean westerlies to zonal mean easterlies is the most important event leading to the spring maximum. The final warming is not followed by reacceleration of the mean flow; so that the ozone transport associated with this event is more pronounced than that associated with midwinter warmings.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Pure and Applied Geophysics (ISSN 0033-4553); 121; 5-6,
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  • 35
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    Conservation laws of wave action and potential enstrophy for Rossby waves in a stratified atmosphere (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The evolution of wave energy, enstrophy, and wave motion for atmospheric Rossby waves in a variable mean flow are discussed from a theoretical and pedagogic standpoint. In the absence of mean flow gradients, the wave energy density satisfies a local conservation law, with the appropriate flow velocity being the group velocity. In the presence of mean flow variations, wave energy is not conserved, but wave action is, provided the mean flow is independent of longitude. Wave enstrophy is conserved for arbitrary variations of the mean flow. Connections with Eiiassen-Palm flux are also discussed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Pure and Applied Geophysics (ISSN 0033-4553); 121; 5-6,; 917-946
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  • 36
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    A parameterization of the absorption in the 15 micron CO2 spectral region with application to climate sensitivity studies (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A technique for quantifying the absorption that takes place in the 15 micron CO2 band in the atmosphere is developed as a function of the scaled CO2 content. A spectrally averaged transmission function is defined and a scaling approximation for the absorption coefficient is calculated, as is the width of the absorption band. An assessment is made of the accuracies of the parameterized atmospheric transmittance and cooling rate. The resulting radiation parameterization is applied in a climate sensitivity study. The model is concluded useful in examining atmospheres with a variable CO2 content, with the highest accuracies being available in the troposphere and the lower stratosphere. CO2 doubling the earth's atmosphere is projected to cause a 20 percent warming in the surface temperatures and a 30 percent warming for the tripling of the CO2 content, provided the spectral range for CO2 absorption is extended from 580-760 to 540-800/cm.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; 2183-219
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  • 37
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    The southern oscillation and long-range forecasting of the summer monsoon rainfall over India (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Indian summer monsoon rainfall and the Darwin pressure anomalies are examined for the 81-year period 1901-81. It is found that the tendency of the Darwin pressure anomaly before the monsoon season is a good indicator of the monsoon rainfall anomaly. During the 81-year period, there were only two instances (1901, 1941) when a negative tendency of winter (December, January, February) to spring (March, April, May) Darwin pressure anomaly was followed by a monsoon rainfall anomaly of less than minus one standard deviation; and only three instances (1916, 1933, 1961) when a positive tendency was followed by a rainfall anomaly of more than one standard deviation. Therefore, if the Darwin pressure anomaly during March, April and May is below normal, and if the Darwin seasonal pressure anomaly has been falling, a non-occurrence of drought over India can be predicted with a very high degree of confidence. Similarly, above normal Darwin pressure during March, April and May, and increasing seasonal pressure anomaly is a good indicator of the non-occurrence of very heavy rain over India.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; 1830-183
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  • 38
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    Interpretation of vector magnetograph data including magneto-optic effects. I - Azimuth angle of the transverse field (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In this paper, the presence of Faraday rotation in measurements of the orientation of a sunspot's transverse magnetic field is investigated. Using observations obtained with the Marshall Space Flight Center's (MSFC) vector magnetograph, the derived vector magnetic field of a simple, symmetric sunspot is used to calculate the degree of Faraday rotation in the azimuth of the transverse field as a function of wavelength from analytical expressions for the Stokes parameters. These results are then compared with the observed rotation of the field's azimuth which is derived from observations at different wavelengths within the Fe I 5250 A spectral line. From these comparisons, it is found: the observed rotation of the azimuth is simulated to a reasonable degree by the theoretical formulations if the line-formation parameter is varied over the sunspot; these variations are substantiated by the line-intensity data; for the MSFC system, Faraday rotation can be neglected for field strengths less than 1800 G and field inclinations greater than 45 deg; to minimize the effects of Faraday rotation in sunspot umbrae, MSFC magnetograph measurements must be made in the far wings of the Zeeman-sensitive spectral line.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 88; 51-64
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  • 39
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    Dynamics of a surge observed in the C IV and H alpha lines (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Time sequences of a surge have been obtained in Active Region 2701 during a coordinated SMY program, on October 2nd, 1980, while the MSDP spectrograph operated in H-alpha at the Meudon Solar Tower and the UVSP spectrometer on SMM observed in the 1548 A C IV resonance line. The cold (H-alpha) and hot (C IV) material follow the same channel, and the event lasts about 10 min in both lines. A good correlation is found between H-alpha and C IV velocities; radial velocities along the surge are in the range 40-60 km/s in both cases. The observations are consistent with the hypothesis that a pressure gradient drives the surge. The H-alpha data seem to indicate the presence of a shock wave in the chromosphere, while the C IV quantities (velocities, accelerations) vary on a very short time scale. Their maxima occur at some locations which could be interpreted as 'pinched' zones.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 127; 2, No; 337-344
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  • 40
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    The utilization of Nimbus-7 SMMR measurements to delineate rainfall over land (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Approaches for developing an improved passive microwave technique to delineate rain from wet land surfaces are considered, and an investigation is conducted with the objective to study the application of these ideas with empirical data. The investigation includes a statistical analysis of Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) 37.0, 18.0, and 10.7 GHz data. The possibility was assessed to make use of the 18.0 and 10.7 GHz channels in order to reduce the ambiguities found in the 37.0 GHz radiometer data for differentiating rainfall areas from wet land surfaces. It was found, however, that none of the SMMR channels could differentiate rain from wet or dry land when surface temperatures were less than 15 C. It appears that an improved rainfall-over-land detection technique could be developed by two different methods, utilizing both satellite infrared and multifrequency dual polarized passive microwave data.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate and Applied Meteorology (ISSN 0733-3021); 22; 1753-176
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  • 41
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    Light extinction by aerosols during summer air pollution (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In order to utilize satellite measurements of optical thickness over land for estimating aerosol properties during air pollution episodes, the optical thickness was measured from the surface and investigated. Aerosol optical thicknesses have been derived from solar transmission measurements in eight spectral bands within the band lambda 440-870 nm during the summers of 1980 and 1981 near Washington, DC. The optical thicknesses for the eight bands are strongly correlated. It was found that first eigenvalue of the covariance matrix of all observations accounts for 99 percent of the trace of the matrix. Since the measured aerosol optical thickness was closely proportional to the wavelength raised to a power, the aerosol size distribution derived from it is proportional to the diameter (d) raised to a power for the range of diameters between 0.1 to 1.0 micron. This power is insensitive to the total optical thickness. Changes in the aerosol optical thickness depend on several aerosol parameters, but it is difficult to identify the dominant one. The effects of relative humidity and accumulation mode concentration on the optical thickness are analyzed theoretically, and compared with the measurements.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate and Applied Meteorology (ISSN 0733-3021); 22; 1694-170
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  • 42
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    Differences in the temporal variations of solar UV flux, 10.7-cm solar radio flux, sunspot number, and Ca-K plage data caused by solar rotation and active region evolution (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Attention is given to two types of temporal variations in the solar UV spectral irradiance caused by solar rotation and active region evolution. It is noted that the first type of dissimilar temporal behavior occurs when concentrations of solar active regions evolve at solar longitudes nearly 180 deg apart. Both the UV observations and modeled UV fluxes based on Ca-K plage data then exhibit pronounced 13-day periodicity, whereas the 10.7-cm solar radio flux and sunspot number exhibit quite dissimilar temporal variations. This type of dissimilarity is related to the modeled UV flux and has a dependence on the solar central meridian distance that is narrower than that for the 10.7-cm radio flux or for sunspot numbers. A second case of marked dissimilarity is seen when major new solar active regions arise and dominate the full-disk fluxes for several rotations. It is found that the strongest peaks in 10.7 cm and sunspot numbers tend to occur on their first rotation, for example, during major dips in the total solar irradiance, whereas the Ca-K plages and UV enhancements peak on the next rotation and then decay more slowly on subsequent rotations.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 9883-988
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  • 43
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    The stability of coronal loops - Finite-length and pressure-profile limits (1983)
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    Publication Date: 2011-08-18
    Description: Results are described from a quickly converging, necessary-and-sufficient, MHD-stability test for coronal-loop models. The primary stabilizing influence arises from magnetic line tying at the photosphere, and this end conditions requires a series expansion of possible loop excitations. The stability boundary is shown to quickly approach a limit as the number of terms increases, providing a critical length for the loop in proportion to its transverse magnetic scale. Several models of force-free-field profiles are tested and the stability behavior of a localized current channel, embedded in an external current-free region, is shown to be superior to that of other, broader, current profiles. Pressure-gradient effects, leading to increased or decreased stability, are shown to be amplified by line tying. Long loops must either conduct low net current, or exhibit an axial-field reversal coexisting with a low-pressure core. The limits on stability depend on the magnetic aspect ratio, the plasma-to-magnetic pressure ratio, and the field orientation at the loop edge. Applications of these results to the structure of coronal loops are described.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics (ISSN 0038-0938); 88; 163-177
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  • 44
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    Implications of high-energy neutron observations from solar flares (1983)
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    Publication Date: 2011-08-18
    Description: The time-dependent flux of high-energy neutrons discovered from the solar flare of 1980 June 21 provides a new technique for determining the total number and energy spectrum of accelerated protons and nuclei at the sun. The implications of these observations on gamma-ray emission, relativistic electron spectrum and number, proton and electron energy contents, and the location of the interaction region are also examined.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 273; L41-L45
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  • 45
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    Fluid motions in the solar chromosphere-corona transition region. IV - Mass motions over sunspot umbrae (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 273; 374-380
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  • 46
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    Differential versus limiter-discriminator detection of narrow-band FM (1983)
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    Publication Date: 2011-08-18
    Description: The error probability performance of differential detection of narrow-band FM is determined and compared with the analogous results for limiter-discriminator detection of the same modulation. It is shown that over a large class of benign and hostile environments, e.g., Gaussian IF filter, AWGN, partial-band noise jamming, the differential detector offers no theoretical performance advantage over the limiter-discriminator receiver with integrate-and-dump postdetection filtering.
    Keywords: COMMUNICATIONS AND RADAR
    Type: IEEE Transactions on Communications (ISSN 0090-6778); COM-31; 1227-123
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  • 47
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    Solar irradiance variations. II - Analysis of the extreme ultraviolet measurements onboard the Atmosphere Explorer E satellite (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Five of the extreme ultraviolet channels (L-alpha, L-beta, He I, He II, Fe XV) measuring irradiance fluctuations on board the AE-E satellite between 1977 and 1980 have been studied in detail. It is shown that the daily variations correspond very closely to the daily variations in solar radio emission (F10.7), but that the UV data are afflicted with serious and to date unrecognized calibration changes during the period of operation of the instruments. In order to correct for these changes, a statistical analysis is carried out, and a set of corrections to the raw data is suggested. The resulting, now uniform, data are then compared with rocket measurements (L-alpha) and data acquired onboard the AE-C satellite (L-beta). Finally the remaining discrepancies are discussed. After concluding that they are below the overall level of uncertainties, a first-order 10-year run of EUV irradiances derived from F10.7 data is proposed. This estimate includes the ratio of irradiance levels between the maxima of solar cycles 20 and 21 and the intervening minimum.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; 9037-905
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  • 48
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    Determining the solar wind speed above active regions using remote radio-wave observations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A new technique has made it possible to measure the velocity of portions of the solar wind during its flow outward from the sun. This analysis utilizes spacecraft (ISEE-3) observations of radio emission generated in regions of the solar wind associated with solar active regions. By tracking the source of these radio waves over periods of days, it is possible to measure the motion of the emission regions. Evidence of solar wind acceleration during this outward flow, consistent with theoretical models, has also been obtained.
    Keywords: SOLAR PHYSICS
    Type: Science (ISSN 0036-8075); 222; 506-508
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  • 49
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    An analysis of the 'Blizzard of '88' (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The analysis of the blizzard, an intense cyclone that was accompanied by unusually heavy snowfall, high winds, and cold temperatures, is carried out using a collection of detailed surface weather observations. It follows the cyclone from its genesis along a slow-moving frontal system through its rapid development and occlusion along the Middle Atlantic and southern New England coasts. Unusual aspects of the cyclone are discussed. Among these are the limited areal extent of heavy snow accumulations, the establishment of very cold air across western New England and the Middle Atlantic states, a persistent stationary front zone across central New England that separated frigid continental air from maritime air, and the slow movement and rapid warming associated with the decay of the storm.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: American Meteorological Society, Bulletin (ISSN 0003-0007); 64; 1258-127
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  • 50
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    Stratospheric water vapor variability for Washington, DC/Boulder, CO - 1964-82 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Measurements for Washington, DC and Boulder, CO are combined to provide a time series of midlatitude stratospheric water vapor data for the period 1964-82. The mean concentration for the data period is shown to be nearly constant with altitude for the low stratospheric layer between 16-22 km with a mass mixing ratio for the layer of 2.5-2.6 ppmm. Above 22 km the mixing ratio increases slightly with altitude. Evident in the 60 mb level time series is an annual cycle, a quasi-biennial cycle and a long-term nonlinear trend. The quasi-biennial cycle in water vapor at midlatitudes is consistent with variations in tropical stratosphere zonal winds and temperature and total ozone and suggests a modulation of the Hadley cell circulation. The long-term trend shows mixing ratio increasing during the 1960s and decreasing in the 1970s after 1972.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; 2157-216
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  • 51
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    A satellite stereoscopic technique to estimate tropical cyclone intensity (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The techniques used to obtain the mean equivalent temperature of the eye wall for Hurricanes Frederic (1979) and Allen (1980) using GOES satellite IR and stereoscopic observations are described. The eye wall is the area of greatest convection near the center of the storm, and is bounded by the inner radius around the eye and the outer radius bounding the area of inner core convection. The stereoscopic capability afforded by the GOES West and East spacecraft permits simultaneous, two-view imagery of a tropical cyclone, yielding height measurement accuracies of 0.5 km and horizontal accuracies as small as 1 km. An airborne lidar unit was used to verify the height measurements made of Hurricane Frederic. At the same time, the GOES East Visible IR Spin Scan Radiometer (VISSR) provided the mean wall temperatures from the release of latent heat. The trials aided in identifying the assumptions and consequent inaccuracies introduced into the temperature sounding data during analysis. The satellite data is concluded useful for monitoring changes in storm intensity.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; 1599-161
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    Comparison of a barotropic blocking theory with observation (1981)
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    Publication Date: 2011-08-18
    Description: Hart (1979) showed that the truncated spectral equations obtained by Charney and Devore (1979) could be derived merely by assuming that the cross-stream scale of the topography was large compared to the downstream scale. Since actual topography does not have the large y scales postulated by Hart, his model was modified in the current investigation to obtain equations with arbitrary zonal variations of topography by projecting all variable functions onto the first topographic cross-stream mode. The topographic heights and streamfunctions are expanded as Fourier series in the cross-stream coordinate and the series are truncated after the first term. This accomplishes Hart's results but permits more realistic y variations in the topography. The present investigation is the first in a two-part series. The second part will deal with a two-layer baroclinic channel flow, again with arbitrary zonal variations of topography.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences; 38; Apr. 198
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  • 53
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    Solar Maximum Mission Experiment - Ultraviolet Spectroscopy and Polarimetry on the Solar Maximum Mission (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Ultraviolet Spectrometer and Polarimeter on the Solar Maximum Mission spacecraft is described. It is pointed out that the instrument, which operates in the wavelength range 1150-3600 A, has a spatial resolution of 2-3 arcsec and a spectral resolution of 0.02 A FWHM in second order. A Gregorian telescope, with a focal length of 1.8 m, feeds a 1 m Ebert-Fastie spectrometer. A polarimeter comprising rotating Mg F2 waveplates can be inserted behind the spectrometer entrance slit; it permits all four Stokes parameters to be determined. Among the observing modes are rasters, spectral scans, velocity measurements, and polarimetry. Examples of initial observations made since launch are presented.
    Keywords: SOLAR PHYSICS
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  • 54
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    Combined eye-atmosphere visibility model (1981)
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    Publication Date: 2011-08-18
    Description: Existing models of the optical characteristics of the eye are combined with a recent model of optical characteristics of the atmosphere given by its modulation transfer function. This combination results in the combined eye-atmosphere performance given by the product of their modulation transfer functions. An application for the calculation of visibility thresholds in the case of a two-halves field is given.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Applied Optics; 20; May 1
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  • 55
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    Computations of transmittance and radiance in infrared water vapor sounding channels (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The wing-scaling approximation/k-distribution method, previously developed for computing solar heating rates (Chou and Arking, 1981) was applied to the computation of the transmittance and outgoing radiance in infrared water vapor sounding channels. Functions necessary for the transmittance and radiance computations were computed from molecular line parameters using line-by-line methods. The method was applied to the three HIRS/2 water vapor sounding channels on the TIROS-N satellite, and its accuracy was tested using 11 widely separated atmospheres which ranged from hot-wet tropical atmospheres to cold-dry subarctic atmospheres. Compared to line-by-line calculations, maximum errors were shown to be less than 0.017 in transmittance and 0.4 K in brightness temperature for all cases. The rms errors are less than 0.009 in transmittance and 0.2 K in brightness temperature, the brightness temperature rms error being much smaller than the instrument noise.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review; 109; Mar. 198
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  • 56
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    High resolution X-ray spectra of solar flares. V - Interpretation of inner-shell transitions in Fe XX-Fe XXIII (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The paper examines high-resolution solar flare iron line spectra recorded between 1.82 and 1.97 A by a spectrometer flown by the Naval Research Laboratory on an Air Force spacecraft launched on 1979 February 24. The emission line spectrum is due to inner-shell transitions in the ions Fe XX-Fe XXV. Using theoretical spectra and calculations of line intensities obtained by methods discussed by Merts, Cowan, and Magee (1976), electron temperatures as a function of time for two large class X flares are derived. These temperatures are deduced from intensities of lines of Fe XXII, Fe XXIII, and Fe XXIV. The determination of the differential emission measure between about 12-million and 20-million K using these temperatures is considered. The possibility of determining electron densities in flare and tokamak plasmas using the inner-shell spectra of Fe XXI and Fe XX is discussed.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 245
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    An objective method for forecasting tropical cyclone intensity using Nimbus-5 electrically scanning microwave radiometer measurements (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An empirical analysis program, based on finding an optimal representation of the data, is applied to 120 observations of 29 1973 and 1974 North Pacific tropical cyclones. It is found that the algorithms developed from the Nimbus-5 Electrically Scanning Microwave Radiometer (ESMR-5) base alone outperformed the Joint Typhoon Warning Center (JTWC) operational forecast for the 48 and 72 hour maximum wind speed. It is also found that the ESMR-5 data base, when combined with the non-satellite base, produced algorithms that improved the 24 and 48 hour maximum wind-speed forecast by as much as 10% and the 72 hour maximum wind forecast by approximately 16% as compared to the forecast obtained from the algorithms developed from the non-satellite data base alone.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Applied Meteorology; 20; Feb. 198
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    Preliminary observations and results obtained with the ultraviolet spectrometer and polarimeter (1981)
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    Publication Date: 2011-08-18
    Description: New observation with the Ultraviolet Spectrometer and Polarimeter (UVSP) of a number of manifestations of solar activity obtained during the first three months of Solar Maximum Mission operations are presented. Attention is given to polarimetry in sunspots, oscillations above sunspots, density diagnostics of transition-zone plasmas in active regions, and the eruptive prominence - coronal transient link.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 244
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  • 59
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    The solar flare of 1980 March 29 at 0918 UT as observed with the hard X-ray burst spectrometer on the Solar Maximum Mission (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 244
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  • 60
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    On the polarization state of hydromagnetic fluctuations in the solar wind (1981)
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    Publication Date: 2011-08-18
    Description: From presently available observations one can infer that the Alfvenic turbulence measured in the solar wind, predominantly on trailing edges of high-speed streams, is a mixture of modes with two different polarizations, namely, Alfvenic modes and modes which are the incompressible limit of slow magnetosonic waves. Using Helios 2 magnetic data and a variance analysis, parallel (to the mean field) and perpendicular components of the fluctuations are separated, and the possible correlation between such components which would be predicted as a consequence of the incompressible character of the turbulence is studied. Correlations between eigenvalues of the variance matrix are also investigated and discussed.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 86; Mar. 1
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  • 61
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    Burst statistics of Viterbi decoding (1981)
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    Publication Date: 2011-08-18
    Description: A mathematical model of Viterbi decoder burst error performance is presented. This model allows for computer generation of Viterbi-like error sequences quickly and inexpensively for applications where large amounts of data are required. The model is corroborated through comparisons with actual software decoder simulations.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Telecommun. and Data Acquisition Progr. Rept. 42-64; p 187-193
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  • 62
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    An efficient technique for the performance evaluation of antenna arrays with noisy carrier reference (1981)
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    Publication Date: 2011-08-18
    Description: An efficient computational technique is developed to evaluate the performance of coherent receivers with noisy carrier reference and multiple antennas. The received signal is assumed to be uncoded residual carrier BPSK (binary phase shift keying), with a PLL (phase locked loop) used for extracting the carrier. Explicit relationships between the error probabilities and the various system parameters are given. Specific results are given for the performance gain of combined carrier referencing over baseband only combining when the channel alignment process is ideal. A simple asymptotic expression for the performance gain is determined when the number of antennas used is increased without bound. An example using a Block 3 Deep Space Network PLL illustrates the performance of each arraying structure. The technique used is applicable to the performance evaluation for other receivers having similar decision statistics.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Telecommun. and Data Acquisition Progr. Rept. 42-64; p 194-206
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  • 63
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    The DSN VLBI system Mark 4-85 (1981)
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    Publication Date: 2011-08-18
    Description: The DSN VLBI System was established as a network system in 1978. The evolution of the VLBI System from Mark 1-79 to Mark 4-85 is described, and the system functional requirements for Mark 4-85 are discussed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Telecommun. and Data Acquisition Progr. Rept. 42-64; p 61-76
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  • 64
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    DSN command system (1981)
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    Publication Date: 2011-08-18
    Description: Modification of the currently operational DSN Command System MK 3-80 consisted of improvement of the uplink carrier frequency tuning capability to satisfy Voyager 2 requirements. Upgrading of Command System monitoring functions in the Network Operations Control Center is discussed. The DSN Command System requirements and functional design are described for the Mark 4 Network.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Telecommun. and Data Acquisition Progr. Rept. 42-64; p 53-60
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  • 65
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    Project ORION microwave subsystem design (1981)
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    Publication Date: 2011-08-18
    Description: The proposed design for the microwave subsystem of Project ORION is presented. Performance characteristics and subsystem capabilities are discussed. Functional requirements and key performance parameters are stated for the subsystem as well as a proposed schedule of events.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Telecommun. and Data Acquisition Progr. Rept. 42-64; p 10-17
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  • 66
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    A multiple access communication network based on adaptive arrays (1981)
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    Publication Date: 2011-08-18
    Description: A single frequency communication system is considered consisting of K possibly moving users distributed in space simultaneously communicating with a central station equipped with a computationally adapted array of n = or K antennas. Such a configuration could result if K spacecraft were to be simultaneously tracked by a single DSN complex consisting of an n antennas array. The array employs K sets of n weights to segregate the signals received from the K users. The weights are determined by direct computation based on known position information of the K users. Currently known techniques require (for n = K) about (4/3)K to the 4th power computer operations (multiply and add) to perform such computations. A technique that accomplishes this same goal in 8 K to the 3rd power operations, yielding a reduction by a factor K/6, was developed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Telecommun. and Data Acquisition Rept.; p 118-127
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  • 67
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    Atmospheric noise temperature measurements (1981)
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    Publication Date: 2011-08-18
    Description: Radiometric microwave noise temperature measurements were used to estimate atmospheric transmission loss. The following lumped element model expression is used for the noise temperature contribution, T double prime = T sub p (1 - 1/L). This relationship is used to estimate the transmission loss L in terms of T double prime and the atmosphere effective physical temperature T sub p. This report evaluates T sub p in terms of assumed distributed loss and temperature models. Simplified expressions are presented for low loss applications. For these applications L was determined directly and accurately without integration or iteration.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Telecommun. and Data Acquisition Rept.; p 87-96
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  • 68
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    Effects of the gaseous and liquid water content of the atmosphere on range delay and Doppler frequency (1981)
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    Publication Date: 2011-08-18
    Description: When high precision is required for range measurement on Earth space paths, it is necessary to correct as accurately as possible for excess range delays due to the dry air, water vapor, and liquid water content of the atmosphere. Calculations based on representative values of atmospheric parameters are useful for illustrating the order of magnitude of the expected delays. Range delay, time delay, and phase delay are simply and directly related. Doppler frequency variations or noise are proportional to the time rate of change of excess range delay. Tropospheric effects were examined as part of an overall consideration of the capability of precision two way ranging and Doppler systems.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Telecommun. and Data Acquisition Rept.; p 71-86
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  • 69
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    Time and energy dependence of heavy ion abundances in solar flare energetic particle events (1981)
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    Publication Date: 2011-08-18
    Description: Examples are presented of the time and energy dependence of the abundances and spectra of the major heavy ions He, C, O and Fe during solar flare events, taken from a survey using the UMD/MPI ULET telescope on IMP-8 during 1973-1977. In some cases, time variations were found in the O/He, O/C and Fe/O ratios which appear to be inconsistent with models based solely on rigidity dependent propagation in the interplanetary medium.
    Keywords: SOLAR PHYSICS
    Type: Contrib. to the 17th Intern. Conf. on Cosmic Rays; p 5-8
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  • 70
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    The 34-meter antenna-subreflector translations to maximize RF gain (1981)
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    Publication Date: 2011-08-18
    Description: The extension of the 26 meter antenna to 34 meter diameter decreased the F/D ratio. This F/D change resulted in unacceptable gain losses due to the hyperboloid's lateral deflections. A three direction translating mounting device was added to the hyperboloid. This device was controlled by a microprocessor to minimize the offsets of the phase centers in the cassegrain RF system and also compensated for boresight directions. The use of the radiation program to predict the gain losses from displacements computed by a structural computing program using an analytical model of the 34 meter reflector structure is discussed. Field test results showed accurate predictions for the Y and Z hyperboloid translations. In the X direction, the prediction value was low. However, the computed gain losses vs primary foci offsets by the radiation program were verified by field tests.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Telecommun. and Data Acquisition; p 112-120
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  • 71
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    Frequency standard test facility data acquisition and processing system (1981)
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    Publication Date: 2011-08-18
    Description: The interim frequency standards test facility tests all frequency standards used in the DSN. It is also the central testing facility for testing all ultrastable hydrogen maser frequency standards. This proposed data acquisition/processing system was designed to support the IFSTF by acquiring and processing the large amounts of data generated there.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Telecommun. and Data Acquisition; p 22-30
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  • 72
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    Station stability measurement (1981)
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    Publication Date: 2011-08-18
    Description: Methods and instrumentation are being developed to determine the frequency stability of Deep Space Stations. The efforts are presently focused on the verification of the stability of the X-band uplink and other RF and microwave subsystems which contribute to the overall stability of the system. The measurement methodology is presented as well as frequency stability data generated with the development measurement system. The system characteristics are highlighted and the potential areas where improvements could be made are discussed.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Telecommun. and Data Acquisition; p 35-42
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  • 73
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    Control of large space antennas based on electromagnetic-structural models (1983)
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    Publication Date: 2011-08-18
    Description: A general approach to the optimal control of large space antennas based on their RF/structural characteristics is described. The approach consists of defining a cost functional based on the degradation of the RF performance of the antenna and using the structural model as the dynamic system. The method is applied to the design of an optimal controller for a 55-m, wrap-rib offset-fed antenna. The controller's goal is to minimize the variations of the peak electric field of the antenna due to feed displacements.
    Keywords: COMMUNICATIONS AND RADAR
    Type: Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 181-194
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  • 74
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    The outlook for precipitation measurements from space (1981)
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    Publication Date: 2011-08-18
    Description: The outlook for providing precipitation measurements of useful accuracy and or precision from space is discussed. Visible and infrared techniques, microwave radiometers, spaceborne radar, and altimeters are discussed. Key obstacles are identified.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Precipitation Meas. from Space:; 9 p
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  • 75
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    Adaptively pointing spaceborne radar for precipitation measurements (1981)
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    Publication Date: 2011-08-18
    Description: An auxiliary concept of adaptive pointing applicable to meteorological radar is discussed. This control technique would resolve the conflicts among speed of scan or scan width, resolution, and dwell time per resolution element. At T1(orbital position) a passive infrared radiometer imager scans a swath ahead of the spacecraft; an appropriate algorithm indicates which clouds are probably producing precipitation. These locations are then used by the on-board antenna controller to program the antenna scan so that the radar samples clouds A and B at times T2 and T3 respectively.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Precipitation Meas. from Space:; 9 p
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  • 76
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    Bistatic radar meteorological satellite (1981)
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    Publication Date: 2011-08-18
    Description: A technique is discussed that employs a radar transmitter with a moderate size antenna placed in a geosynchronous orbit with either a 0 degree or a low inclination orbit. The reflected signals from the precipitation are then received either on a single beam from a satellite having a beamwidth of about 6 degrees or preferably with a beam that scans the U.S. in a raster pattern with about 0.9 degrees beamwidth. While it would seem that a bistatic system with the transmitter at synchronous altitude and the receivers near the surface would not be a very efficient way of designing a radar system, it is somewhat surprising that the required power and antenna sizes are not that great. Two factors make the meteorological application somewhat more attractive than the bistatic detection of point targets. First, the bistatic reflections of radar signals from precipitation are to a large extent omnidirectional, and while raindrops are spheriods rather than spheres, the relationship of the reflectivity of the rain to rainfall rate can be easily derived. The second reason is that the rain echo signal level is independent of range from a receive only radar, and if the bistatic system works at all, it will work at long ranges.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 15 p
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  • 77
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    Use of the optimal polarization concept in electromagnetic imaging of hydrometeor distributions (1981)
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    Publication Date: 2011-08-18
    Description: A brief survey is given of some fundamental physical concepts of optimal polarization characteristics of a transmission path or scatterer ensemble of hydrometeors. It is argued that, based on this optimization concepts, definite advances in remote atmospheric sensing are to be expected. Basic properties of Kennaugh's optimal polarization theory are identified.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 15 p
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  • 78
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    Use of combined radar and radiometer systems in space for precipitation measurement: Some ideas (1981)
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    Publication Date: 2011-08-18
    Description: A brief survey is given of some fundamental physical concepts of optimal polarization characteristics of a transmission path or scatter ensemble of hydrometers. It is argued that, based on this optimization concept, definite advances in remote atmospheric sensing are to be expected. Basic properties of Kennaugh's optimal polarization theory are identified.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 25 p
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  • 79
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    Rain rate measurement capabilities using a Seasat type radar altimeter (1981)
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    Publication Date: 2011-08-18
    Description: The combined use of a space-based radar and a radiometer for measurement of precipitation is discussed. Phenomena to exploit or overcome is surveyed. Basic measurement problems are discussed. Several active systems are proposed, including three ocean systems and two land-sea systems. Recommendations for future research are given.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 13 p
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  • 80
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    Satellite borne dual millimetric wave length radar (1981)
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    Publication Date: 2011-08-18
    Description: The failure of attempts to accurately measure precipitation by using a single quality that is used to deduce the desired precipitation parameter through a derived relationship is discussed. A number of dual measurement techniques for the accurate determination of instantaneous rainfall rates from space are proposed. It is concluded that dual measurement techniques show high promise for measuring precipitation parameters with greater accuracy than that which was possible in the past.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 7 p
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  • 81
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    Potential of dual-measurement techniques for accurate determination of instantaneous rainfall rate from space (1981)
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    Publication Date: 2011-08-18
    Description: The incorporation in the 13.5 GHz SEASAT type radar altimeter of a mode to measure rain rate is investigated. Specifically, an algorithm is developed relating the echo power at the various range bins to the rain rate, taking into consideration Mie scattering and path attenuation. The dependence of the algorithm on rain drop size distribution, and non-uniform rain structure are examined and associated uncertainties defined. A technique for obtaining drop size distribution through the measurements of power at the top of the raincell and power difference through the cell is also investigated together with an associated error analysis. A description of the minor hardware modifications to the basic SEASAT design is given for implementing the rain measurements.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 5 p
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  • 82
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    Spaceborne precipitation radar (1981)
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    Publication Date: 2011-08-18
    Description: The performances and characteristics of a satelliteborne radar operating in the millimeter wavelength region of the spectrum with emphasis placed on the 35 and 94 GH3 frequency bands are discussed. It is concluded that millimetric wavelengths provide an acceptable solution for the design of satelliteborne active microwave equipment.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Precipitation Meas. from Space:; 16 p
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  • 83
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    Remote sensing of stored precipitation, i.e., soil moisture and snow (1981)
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    Publication Date: 2011-08-18
    Description: The characteristics and performance of spaceborne precipitation radar systems are discussed. The development of a model is discussed. Examples of simulation results are given. It was found that the accuracy of rain rate estimates is improved by using higher resolution radar.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Precipitation Meas. from Space:; 9 p
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  • 84
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    The DMSP imager (SSMI): Unfinished plans (1981)
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    Publication Date: 2011-08-18
    Description: The basic theory relating microwave emissivity to soil and snow moisture is presented along with data from field and aircraft measurements to support the theory. Data from the ESMR on Nimbus-5 and the S-194 L Band radiometer on Skylab were compared with Antecedent Precipitation indices (APT) to show the sensitivity of spaceborne observations to soil moisture. Similarly, data from the ESMR and SMMR on the Nimbus spacecraft were compared with surface measurements of snow depth with good results.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Precipitation Meas. from Space:; 7 p
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  • 85
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    The utilization of satellite passive microwave sensors to monitor synoptic scale rainfall (1981)
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    Publication Date: 2011-08-18
    Description: A microwave imaging sensor, built for flight on the Defense Meteorological Satellite Program spacecraft, is discussed. Major elements of the sensor development program are summarized as background for planning a data archival program useful for climate research.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Precipitation Meas. from Space:; 13 p
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  • 86
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    Detection of rainfall rates utilizing spaceborne microwave radiometers (1981)
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    Publication Date: 2011-08-18
    Description: To demonstrate the success of utilizing passive microwave sensors in monitoring synoptic scale rainfall, two studies are described in which electrically scanning microwave radiometers (ESMR-5 and 6) on board Nimbus 5 and 6 were employed using a Langrangian frame of reference. The first study suggests a method of utilizing ESMR-5 measurements to quantize rainfall over water within tropical and extratropical storms and to use these measurements to monitor and possibly predict storm intensity. The second study suggests a method of monitoring the coverage and movement of synoptic rain over land by employing ESMR-6.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 7 p
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  • 87
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    Using underwater ambient noise levels to measure rainfall rate: A review (1981)
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    Publication Date: 2011-08-18
    Description: The use of satellite passive microwave radiometry in the determination of precipitation frequencies and areas is discussed. Precipitation detection over the ocean and land and the accuracy of results are addressed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 33 p
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  • 88
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    On the measurement of precipitation frequencies by passive microwave radiometery (1981)
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    Publication Date: 2011-08-18
    Description: Over most of the microwave spectrum, raindrops both absorb and scatter radiation producing large changes in brightness temperatures relative to clear or cloudy conditions. Since the structure of rain varies substantially for different rain rates and climatological backgrounds, the raindrop size distribution, the rain layer thickness and the ice clouds above the rain layer are all important inputs to the model computations. The subsequent modeling involves applying the Mie theory to derive the absorption and scattering effects and the radiative transfer calculation is based upon a variational iterative approach which takes account of the multiple scattering effect of the rain layer. Results over both ocean and land backgrounds are demonstrated. It is also demonstrated that by using discrimination tests of the radiometric data, the rain/no rain decision can be made and the rainfall rate can be retrieved from a statistical inversion technique.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 3 p
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  • 89
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    Combining visible and infrared techniques with LAMMR for daily rainfall estimates (1981)
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    Publication Date: 2011-08-18
    Description: A brief description of other methods of rainfall measurement at the sea surface is given. The general underwater ambient noise background of the ocean is described. The physics of noise generation by bubbles and splashes is reviewed. Monitoring underwater ambient noise levels to measure rainfall rate requires that the spectral shapes of the noise from wind and rain be different or at least distinguishable. This would allow the rain noise to be separated from the wind noise and then hopefully it can be correlated with rainfall rate. Different spectral shapes are observed experimentally.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 9 p
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  • 90
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    A survey of passive microwave and hybrid remote sensing of precipitation (1981)
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    Publication Date: 2011-08-18
    Description: It is noted that for practical realization of new information on precipitation during this decade, satellite observing systems must be coupled into surface-based observations and computer models of weather systems as they develop. Methods to combine the satellite/surface-based/model capabilities are discussed and several precipitation estimation pilot studies are proposed and outlined.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Precipitation Meas. from Space:; 3 p
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  • 91
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    The Bristol method of satellite-improved rainfall monitoring (1981)
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    Publication Date: 2011-08-18
    Description: Remote sensing estimates of area average precipitation are useful to agricultural and climatological applications. Estimates obtained by active or passive microwaves, infrared and visible sensors may be augmented and improved using indirect measures of precipitation, such as the change in near surface soil moisture content caused by a particular event. Measurements of soil moisture using infrared radiances do not provide precipitation information in real time since the sky must clear. However, the resultant estimate of precipitation is a time integrated value which provides a significant savings in data handling and can overcome virtually all of the sampling problems associated with the monitoring of precipitation through storms of long duration.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 11 p
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  • 92
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    Visible and infrared techniques for flash flood, hydrological, and agricultural applications (1981)
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    Publication Date: 2011-08-18
    Description: A common requirement of these agriculture, climatology and hydrology fields is the accurate and timely estimation of precipitation. Yet, it is often difficult to obtain such estimates by conventional means. The advent of satellite remote sensing however has opened the possibility of making rain estimates over time and space scale never before available. A computer automated technique that estimates a summertime convective rainfall from the thermal infrared imagery of geosynchronous satellites is reviewed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 10 p
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  • 93
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    The estimation of convective precipitation from GOES imagery with the Griffith/Woodley technique (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Improved rainfall monitoring using satellite and conventional data are described. A method was developed to: (1) provide rainfall evaluations more uniform, accurate and complete than can be derived from satellite or conventional data alone; (2) serve current operational environmental program in countries with special needs for improved rainfall data; (3) invoke either polar orbiting and/or geostationary imagery as the satellite inputs; (4) utilize global telecommunication system (GTS) SYNOP messages as the basic conventional data inputs; (5) be applicable to any and all types of weather situations in the operational areas; (6) be undemanding in hardware and software so as to be an option available for use even by nations or agencies with very limited financial resources.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 6 p
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  • 94
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    Inference of precipitation through thermal infrared measurements of soil moisture (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The physics of microwave radiative transfer is well understood so that causal models can be assembled which relate the observed brightness temperatures to assumed distributions of hydrometeors (both liquid and ice), non-precipitating clouds, water vapor oxygen, and surface conditions. Present models assume a Marshall Palmer size distribution of liquid hydrometers from the surface to the freezing level (near the 0 C isotherm) and a variable thickness of frozen hydrometeors above that with various reasonable distribution of the other relevant constituents. The validity of such models is discussed. All uncertainties in the rain rate retrieval algorithms can be expressed in terms of specific model uncertainties which can be addressed through appropriate measurements. Those factors which must be known to achieve umambiguous results can be identified so that rainfall measuring algorithms can be developed and improved. The emissivity of the underlying surface significantly affects the contrast that may be measured between areas covered by rain and those which are dry. Sensing strategies for measuring rain over the ocean and rain over land are reviewed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Precipitation Meas. from Space:; 6 p
    Format: text
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    NASA TECHNICAL REPORTS
  • 95
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    A combined visible and IR technique for the estimation of rainfall amounts from GOES data (1981)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The use of visible and infrared techniques for estimating precipitation for flash flood, hydrological, and agricultural applications is discussed. Satellite derived rainfall estimates supplement other data or are the only data available. The Scofield/Oliver convective rainfall technique is used for analyzing a half hour period of heavy rainfall during a Chicago flash flood event. The results of a real time hydrological application of the Scofield/Oliver technique for the Hurricane Allen event are also presented. Visible and IR techniques for agricultural applications are also discussed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 4 p
    Format: text
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  • 96
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    A life history method for estimating convective rainfall (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The remote sensing of rain amounts is of great interest for a great variety of operational applications, including hydrology, hydroelectricity and agriculture is discussed. The microwave radiometer represents the most obvious technique, however, poor spatial and temporal resolution, together with the problems associated with the estimation of effective rain layer height make visible and IR techniques more promising at the present time. Based on bivariate frequency distribution of brightness versus temperature, brightness enhancing or infrared technique alone may be inadequate to deduce details of convective activity. It is implied that better estimates of rainfall will come from visible and IR observations combined than from either used alone. The technique identifies clouds with high probability of rain as those which have large optical and presumably physical thickness as measured by the visible albedo in comparison with their height, determined by the intensity of the IR emission.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 3 p
    Format: text
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    NASA TECHNICAL REPORTS
  • 97
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    Ground truth for oceanic rainfall (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Communications systems operating at frequencies in excess of 10 GHz are degraded significantly by rainfall. To provide the information needed for design of these millimeter wave systems, rain attentuation models were developed and data bases of propagation related information were accumulated. These data bases were developed based on the signal level measurements of geostationary satellite beacons at selected frequencies. Groundbased radar reflection measurements were able to develop data bases for system design. The rain attenuation models allow accurate correlation between the rain rate and the attenuation.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 7 p
    Format: text
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    NASA TECHNICAL REPORTS
  • 98
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    A survey of radar rain measurement techniques (1981)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Oceanic rainfall was extrapolated in the past from land and island measurements. It was uncertain how representative the land measurements were in local and remote oceanic areas. Now several independent oceanic rainfall analyses are available. These analyses are based upon different techniques, yet they produce similar values. It is suggested that island and coastal measurements are suitable to calibrate satellite oceanic rainfall measurements.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 16 p
    Format: text
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    NASA TECHNICAL REPORTS
  • 99
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    Microwave radiometry sampling problems demonstrated with Nimbus 5 rain rates versus GATE data (1981)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The performance of rain estimation techniques is analyzed. The results from the Griffith/Woodley satellite rain estimation technique are tested. Results, although preliminary, allow objective determination of the feasibility of the use of satellite rain estimates at various scales of interest.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 10 p
    Format: text
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    NASA TECHNICAL REPORTS
  • 100
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    A standard verification for rainfall estimation from remote platforms (1981)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Measurements of reflectivity at horizontal (Zh) and vertical (Zy) polarizations provide adequate information necessary to infer the two parameters of an exponential raindrop size distribution (No, Do) where the distribution is given by N(D) = Noexp(-3.67 D/Do). This distribution enables computation of water content or still air rainfall rates. The physical basis of the radar technique is outlined and illustrated theoretically, and experimental results, comparing radar derived rainfall rates with raingage and disdrometer measurements, are reviewed. The technique is useful for many meteorological and hydrological purposes, including ground truth measurements of rainfall rate over the ocean for comparison with satellite related observations.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center Precipitation Meas. from Space:; 4 p
    Format: text
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    NASA TECHNICAL REPORTS
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