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Vonderhaar, T. H.

Publications and source records attributed to Vonderhaar, T. H..

34 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Optimum satellite orbits for accurate measurement of the earth's radiation budget, summary

The optimum set of orbit inclinations for the measurement of the earth radiation budget from spacially integrating sensor systems was estimated for two and three satellite systems. The best set of the two were satellites at orbit inclinations of 80 deg and 50 deg; of three the inclinations were 80 deg, 60 deg and 50 deg. These were chosen on the basis of a simulation of flat plate and spherical detectors flying over a daily varying earth radiation field as measured by the Nimbus 3 medium resolution scanners. A diurnal oscillation was also included in the emitted flux and albedo to give a source field as realistic as possible. Twenty three satellites with different inclinations and equator crossings were simulated, allowing the results of thousand of multisatellite sets to be intercompared. All were circular orbits of radius 7178 kilometers.

Campbell, G. G.↗
NASA NTRS1978

Studies of satellite support to weather modification in the western US region

The applications of meteorological satellite data to both summer and winter weather modification programs are addressed. Appraisals of the capability of satellites to assess seedability, to provide real-time operational support, and to assist in the post-experiment analysis of a seeding experiment led to the incorporation of satellite observing systems as a major component in the Bureau of Reclamations weather modification activities. Satellite observations are an integral part of the South Park Area cumulus experiment (SPACE) which aims to formulate a quantitative hypothesis for enhancing precipitation from orographically induced summertime mesoscale convective systems (orogenic mesoscale systems). Progress is reported in using satellite observations to assist in classifying the important mesoscale systems, and in defining their frequency and coverage, and potential area of effect. Satellite studies of severe storms are also covered.

Cotton, W. R.↗
NASA NTRS1977

Satellite observations of the onset and growth of severe local storms

The mesoscale nature of the forcing and evolution of these storms was investigated, with emphasis on techniques to aid in the early detection of such severe events. In the pre-storm environment (t-4 to t-2 hours), the satellite wind fields were combined with moisture parameters to derive horizontal moisture flux information. Low level moisture convergence was indicative of regions of subsequent severe storm genesis. Dynamic parameters such as boundary layer vorticity production and relative vorticity were also useful prognosticators of subsequent severe activity.

Negri, A. J.↗
NASA NTRS1976

Radiation measurements from polar and geosynchronous satellites

Towards understanding the role of radiation in the dynamics of climate, a climatology of radiation budget data has been compiled and several aspects of the problem are under study: (1) minimum albedoes; (2) diurnal variation in cloudiness and the radiation budget; (3) the partitioning of energy loss to space between land, ice, ocean and atmosphere; and (4) the effects of clouds on the radiation budget. Oceanic precipitation using Nimbus 5 microwave data, and a new study of mesoscale applications of satellite infrared temperature and moisture soundings are also described.

Vonderhaar, T. H.↗
NASA NTRS1976

Mesoscale temperature and moisture fields from satellite infrared soundings

The combined use of radiosonde and satellite infrared soundings can provide mesoscale temperature and moisture fields at the time of satellite coverage. Radiance data from the vertical temperature profile radiometer on NOAA polar-orbiting satellites can be used along with a radiosonde sounding as an initial guess in an iterative retrieval algorithm. The mesoscale temperature and moisture fields at local 9 - 10 a.m., which are produced by retrieving temperature profiles at each scan spot for the BTPR (every 70 km), can be used for analysis or as a forecasting tool for subsequent weather events during the day. The advantage of better horizontal resolution of satellite soundings can be coupled with the radiosonde temperature and moisture profile both as a best initial guess profile and as a means of eliminating problems due to the limited vertical resolution of satellite soundings.

Hillger, D. W.↗
NASA NTRS1974

Radiation measurements from polar and geosynchronous satellites

Nimbus 5 satellite data and its use to study climate and develop climate model experiments are examined. Data cover: (1) physical basis for understanding long range and climate monitoring and prediction problem, (2) delineating energy loss to space between contributions from land, ocean, and atmosphere, (3) temporal and spatial distribution in earth's energy budget and its variations due to global cloud fields, and (4) studies of the frequency of occurrence of precipitation over ocean areas.

Vonderhaar, T. H.↗
NASA NTRS1974

Atlas of radiation budget measurements from satellites, 1962 - 1970

Radiation budget data measured at the top of the atmosphere by earth-orbiting satellites for various time periods in the years 1962 through 1970 are presented in the form of contoured maps which were derived from 5 seasonal and 25 monthly and semimonthly data sets. The data are values of planetary albedo, infrared radiant exitance, absorbed solar energy, net radiation balance. Documentation and contoured maps are included together with data tabulation at each 10 deg latitude and longitude. Additional data published by other authors are referenced.

Vonderhaar, T. H.↗
NASA NTRS1974

Radiation measurements over a snowfield at an elevated site

The components of short wave radiation were measured over a snowfield in a valley of the Rocky Mountains at a height of 2700 m above sea level. Global and reflected radiation were obtained by a set of Eppley pyranometers. In addition, the direct solar radiation and the turbidity of the atmosphere were derived from pyrheliometric data on cloud-free days. Emphasis was given to the reflectance of the snowfield in relation to the position of the sun, especially at low elevation angles. These reflectance values were measured for cloudless as well as for cloudy days and compared with already published values for arctic and antarctic conditions.

Korff, H. C.↗
NASA NTRS1973

Interhemispheric comparison of atmospheric circulation features as evaluated from Nimbus satellite data

A relationship is established between relative geostrophic vorticity on an isobaric surface and the Laplacian of the underlying layer-mean temperature. This relationship is used to investigate the distribution of vorticity and baroclinicity in a jet-stream model which is constantly recurrent in the winter troposphere. The investigation shows that the baroclinic and vorticity fields of the extratropical troposphere must be bifurcated with two extrema in the middle and subpolar latitudes. This pattern is present in daily tropospheric meridional cross-sections. The reasons for the disappearance of bifurcation in the time-and-longitude averaged distributions are discussed.

Reiter, E. R.↗
NASA NTRS1973

The radiation balance of the earth-atmosphere system from Nimbus 3 radiation measurements

The radiation balance of the earth-atmosphere system and its components was computed from global measurements of radiation reflected and emitted from the earth to space. These measurements were made from the meteorological satellite Nimbus 3 during the periods from April 16 to August 15, 1969; October 3 to 17, 1969; and January 21 to February 3, 1970. Primarily the method of evaluation, its inherent assumptions, and possible error sources were discussed. Results are presented by various methods: (1) global, hemispherical, and zonal averages obtained from measurements in all semimonthly periods and (2) global maps of the absorbed solar radiation, the albedo, the outgoing longwave radiation, and the radiation balance obtained from measurements during semimonthly periods in each season (May 1 to 15, July 16 to 31, and October 3 to 17, 1969, and January 21 to February 3, 1970). Annual global averages of the albedo and of the outgoing longwave radiation were determined. These values balance to within 1 percent the annual global energy input by solar radiation that was computed for a solar constant.

Raschke, E.↗
NASA NTRS1973

Radiation measurements from polar and geosynchronous satellites

During the 1960's, radiation budget measurements from satellites have allowed quantitative study of the global energetics of our atmosphere-ocean system. A continuing program is planned, including independent measurement of the solar constant. Thus far, the measurements returned from two basically different types of satellite experiments are in agreement on the long term global scales where they are most comparable. This fact, together with independent estimates of the accuracy of measurement from each system, shows that the energy exchange between earth and space is now measured better than it can be calculated. Examples of application of the radiation budget data were shown. They can be related to the age-old problem of climate change, to the basic question of the thermal forcing of our circulation systems, and to the contemporary problems of local area energetics and computer modeling of the atmosphere.

Vonderhaar, T. H.↗
NASA NTRS1972

Interhemispheric comparison of atmospheric circulation features as evaluated from Nimbus satellite data

The report includes a complete analyses of O3 data inferred from Nimbus-3 measurements, a discussion of future areas of study, description of the regression and inversion methods developed to infer atmospheric temperature and tropopause characteristics, as well as the plan to process the satellite data for a systematic study of the relative circulation differences between Northern and Southern Hemispheres.

Reiter, E. R.↗
NASA NTRS1972

Measurements of the energy exchange between earth and space from satellites during the 1960's

The net radiation budget of the earth-atmosphere system can be obtained from satellite measurements of the infrared radiant emittance and reflected and scattered solar radiation along with a knowledge of the solar constant. During the 1960's experimental and operational meteorological satellites carrying thermistor bolometer sensors were in orbit for about 60 months. Results from these measurements are given including: a global planetary albedo of 30%, long-term global radiation balance within measurement accuracy (2-3%), the net equator-to-pole radiation gradients that drive our atmospheric and oceanic circulations, as well as selected measurements of radiation budget terms over particular geographical areas.

Vonderhaar, T. H.↗
NASA NTRS1971

Radiation measurements from polar and geosynchronous satellites

Measurements of the earth's radiation budget, its climatology and its interannual variation, are described briefly. In addition, preliminary results are given on ocean energy transports, specific large scale and local radiation budget anamolies, and studies of the separate radiation budgets of the atmosphere and ocean. Initial work in preparation for additional radiation budget measurements from EOS and ATS satellites is described. A radiation budget system simulation program and several smaller projects (including a radiance normalization technique) are also mentioned. First annual global maps of the earth's radiation budget as measured from Nimbus 3 are included.

Vonderhaar, T. H.↗
NASA NTRS1971

Interhemispheric comparison of atmospheric circulation features as evaluated from NIMBUS satellite data

Findings are presented for IRIS data from NIMBUS 3 in mapping the global ozone distribution. The seasonal and regional variations of ozone, especially in the Southern Hemisphere, reveal features that were not evident from the sparse ground-based ozone observation network in this hemisphere. A regression analysis was undertaken for temperature and height fields on radiance data. Spectrum analyses of upper wind data from the North American section and Australia were completed.

Reiter, E. R.↗