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Abstract
In this paper, the algorithm used for calculating the water vapor distribution from SIRS-B spectral radiances is given. Examples are presented illustrating the effects of errors in the water vapor absorption coefficients and the specified temperature profile on the retrieval of the water vapor profile. Comparisons of satellite-derived and radiosonde-observed water vapor profiles indicate that the errors of the SIRS-derived relative humidity in the middle troposphere (i.e., the 400–600 mb layer) are less than 20%. Relative humidity errors in the lower troposphere (600–1000 mb) are somewhat larger but still less than 30%.
Abstract
In this paper, the algorithm used for calculating the water vapor distribution from SIRS-B spectral radiances is given. Examples are presented illustrating the effects of errors in the water vapor absorption coefficients and the specified temperature profile on the retrieval of the water vapor profile. Comparisons of satellite-derived and radiosonde-observed water vapor profiles indicate that the errors of the SIRS-derived relative humidity in the middle troposphere (i.e., the 400–600 mb layer) are less than 20%. Relative humidity errors in the lower troposphere (600–1000 mb) are somewhat larger but still less than 30%.
Abstract
A new technique is formulated for using eigenvectors of covariance matrices to retrieve atmospheric parameters from spectral radiance observations. The eigenvector method permits the use of all spectral radiances in a simultaneous solution for cloud-free infrared sounding radiances from cloud-contaminated observations as well as for the vertical profiles of temperature, moisture and cloudiness. The effects of random observation errors are minimized without suppressing the influence of any real information structure contained in the spectral radiance distribution. Also, since the method provides for the most economical representation of any variable from a number of “terms required” point of view, computer storage and computation requirements are much less than those of other methods.
The eigenvector method is tested using radiance observations synthesized for the Nimbus-6 infrared and microwave sounding instruments. Although the method has been successfully applied for the routine processing of observations obtained from the Nimbus-6 satellite, these results will be presented in a future report.
Abstract
A new technique is formulated for using eigenvectors of covariance matrices to retrieve atmospheric parameters from spectral radiance observations. The eigenvector method permits the use of all spectral radiances in a simultaneous solution for cloud-free infrared sounding radiances from cloud-contaminated observations as well as for the vertical profiles of temperature, moisture and cloudiness. The effects of random observation errors are minimized without suppressing the influence of any real information structure contained in the spectral radiance distribution. Also, since the method provides for the most economical representation of any variable from a number of “terms required” point of view, computer storage and computation requirements are much less than those of other methods.
The eigenvector method is tested using radiance observations synthesized for the Nimbus-6 infrared and microwave sounding instruments. Although the method has been successfully applied for the routine processing of observations obtained from the Nimbus-6 satellite, these results will be presented in a future report.
Abstract
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No Abstract Available.
Abstract
The U.S. Weather Bureau has been experimenting with a radar operating on the Doppler principle to determine whether apparatus of this type would detect and uniquely identify tornadoes. The principles of Doppler radar as applied to meteorology and results of recent experiments with equipment of this type are discussed. Calculations of anomalous wind speeds of 206 m.p.h. in a funnel cloud and 94 m.p.h. in a dust devil are presented in detail. In addition, data have been gathered from squall lines and isolated thunderstorms. Recommendations are made for an optimum Doppler radar system for the detection of tornadoes.
Abstract
The U.S. Weather Bureau has been experimenting with a radar operating on the Doppler principle to determine whether apparatus of this type would detect and uniquely identify tornadoes. The principles of Doppler radar as applied to meteorology and results of recent experiments with equipment of this type are discussed. Calculations of anomalous wind speeds of 206 m.p.h. in a funnel cloud and 94 m.p.h. in a dust devil are presented in detail. In addition, data have been gathered from squall lines and isolated thunderstorms. Recommendations are made for an optimum Doppler radar system for the detection of tornadoes.
Abstract
Cloud altitudes specified from the Infrared Temperature Profile Radiometer on the Nimbus 5 satellite are compared with simultaneous observations by radiosonde and ground-based ranging measurements conducted with the lidar system at CSIRO in Aspendale, Victoria, Australia, during September 1976. The results show that the cloud altitudes deduced by the CO2 channel absorption method are in general agreement with the lidar and radiosonde determinations, regardless of the cloud opacity and amount.
Abstract
Cloud altitudes specified from the Infrared Temperature Profile Radiometer on the Nimbus 5 satellite are compared with simultaneous observations by radiosonde and ground-based ranging measurements conducted with the lidar system at CSIRO in Aspendale, Victoria, Australia, during September 1976. The results show that the cloud altitudes deduced by the CO2 channel absorption method are in general agreement with the lidar and radiosonde determinations, regardless of the cloud opacity and amount.
Abstract
A composite histogram method is used to objectively derive sea-surface temperature distribution from satellite radiation measurements for the Northern and Southern Hemispheres. Comparisons with conventional observations yield root-mean-square differences of 2°–3°K. Some of the differences can be accounted for by factors such as the coherent noise introduced by the onboard tape recorder, insufficient atmospheric attenuation corrections, and basic differences between the two types of temperature measurements.
Abstract
A composite histogram method is used to objectively derive sea-surface temperature distribution from satellite radiation measurements for the Northern and Southern Hemispheres. Comparisons with conventional observations yield root-mean-square differences of 2°–3°K. Some of the differences can be accounted for by factors such as the coherent noise introduced by the onboard tape recorder, insufficient atmospheric attenuation corrections, and basic differences between the two types of temperature measurements.
Abstract
A CO2 cloud tracking technique to determine simultaneous heights and velocities of cloud motion winds is presented. Using animated CO2 channel imagery from VAS, multi-level cloud situations are separated into high, middle and low level cloud motion wind vectors by the CO2 slicing method. The VAS CO2 channel radiometric values are used in the CO2 absorption method to assign quantitative heights to the cloud vectors; cloud top pressures are determined from the ratio of the deviations in cloud produced radiances and the corresponding clear air values for three CO2 channels in a radiative transfer equation formulation. Two case studies are presented that show CO2 cloud-motion wind vectors to be in good agreement with radiosonde wind observations and CO2 cloud heights to be within a 50 mb rms deviation of radiosonde, bispectral and stereo height determinations.
Abstract
A CO2 cloud tracking technique to determine simultaneous heights and velocities of cloud motion winds is presented. Using animated CO2 channel imagery from VAS, multi-level cloud situations are separated into high, middle and low level cloud motion wind vectors by the CO2 slicing method. The VAS CO2 channel radiometric values are used in the CO2 absorption method to assign quantitative heights to the cloud vectors; cloud top pressures are determined from the ratio of the deviations in cloud produced radiances and the corresponding clear air values for three CO2 channels in a radiative transfer equation formulation. Two case studies are presented that show CO2 cloud-motion wind vectors to be in good agreement with radiosonde wind observations and CO2 cloud heights to be within a 50 mb rms deviation of radiosonde, bispectral and stereo height determinations.
Abstract
A seven-channel Multi-spectral Scanning Radiometer (MSR) was flown aboard the NASA Convair-990 aircraft during the GARP Atlantic Tropical Experiment (GATE) from June–September, 1974. The radiometer measures the total shortwave (0.2–5 μm) and longwave (5–50 μm) components of radiation and the radiation in specific absorption band and window regions that modulate the total radiation flux. Measurements of the angular distribution of radiation, including the upward and downward components, were obtained. The principal scientific objective of the MSR experiment was to obtain the atmospheric absorption data required for precise computations of radiative heating profiles from atmospheric state parameters. The method used to construct the infrared radiation heating computational model based on in situ GATE MSR observations is described. Radiative heating profiles computed with this model for both cloudy and cloudless atmospheres were compared with direct observations by flux radiometers and with profiles computed with the Rodgers and Walshaw model. The results indicate that the empirically based computational model should provide tropospheric radiative heating profiles sufficiently accurate for diagnostic and prognostic applications of GATE data.
Abstract
A seven-channel Multi-spectral Scanning Radiometer (MSR) was flown aboard the NASA Convair-990 aircraft during the GARP Atlantic Tropical Experiment (GATE) from June–September, 1974. The radiometer measures the total shortwave (0.2–5 μm) and longwave (5–50 μm) components of radiation and the radiation in specific absorption band and window regions that modulate the total radiation flux. Measurements of the angular distribution of radiation, including the upward and downward components, were obtained. The principal scientific objective of the MSR experiment was to obtain the atmospheric absorption data required for precise computations of radiative heating profiles from atmospheric state parameters. The method used to construct the infrared radiation heating computational model based on in situ GATE MSR observations is described. Radiative heating profiles computed with this model for both cloudy and cloudless atmospheres were compared with direct observations by flux radiometers and with profiles computed with the Rodgers and Walshaw model. The results indicate that the empirically based computational model should provide tropospheric radiative heating profiles sufficiently accurate for diagnostic and prognostic applications of GATE data.
Abstract
Pressure, density, temperature and wind measurements in the upper stratosphere and in the mesosphere resulted from a total of 53 rocket-grenade soundings conducted during the period 1960–1965. Most of the soundings were performed over North America (Wallops Island, 38N and Churchill, 59N) but some results were also obtained over the tropical Atlantic (Ascension Island, 8S) and over Northern Europe (Kronogard, 66N). Soundings were carried out simultaneously at these sites and were coordinated with soundings measing similar parameters over other areas of the globe.
Seasonal and latitudinal variations in the structure and circulation of this region of the atmosphere were derived from the results. Stratosphere temperatures vary with season and latitude in accordance with solar heating rates and with established circulation models. Temperatures above 65 km are substantially warmer in winter than in summer. Average seasonal temperature differences are about 40K at 80 km. They are very pronounced at midlatitudes (Wallops Island) and become even more extreme at high latitudes where in summer mesopause temperatures as low as 140K were observed. Maximum stratopause temperatures were observed during late winter-early summer. At Wallops Island these maxima of about 280K coincided with the period of transition from winter to summer circulation. Temperature profiles for all seasons at all sites intersect between 60 and 65 km at a temperature range of 230 to 240K.
The strong westerly flow in winter shows two pronounced cores, one persistent throughout the winter just above the stratopause, the other somewhat weaker and less persistent near 75 km. Deviations from the zonal flow indicate the existence of meteorological circulation cells on a synoptic scale with the average meridional flaw at Churchill strongly from the north during both summer and winter and at Wallops Island somewhat weaker from the south during the winter.
Abstract
Pressure, density, temperature and wind measurements in the upper stratosphere and in the mesosphere resulted from a total of 53 rocket-grenade soundings conducted during the period 1960–1965. Most of the soundings were performed over North America (Wallops Island, 38N and Churchill, 59N) but some results were also obtained over the tropical Atlantic (Ascension Island, 8S) and over Northern Europe (Kronogard, 66N). Soundings were carried out simultaneously at these sites and were coordinated with soundings measing similar parameters over other areas of the globe.
Seasonal and latitudinal variations in the structure and circulation of this region of the atmosphere were derived from the results. Stratosphere temperatures vary with season and latitude in accordance with solar heating rates and with established circulation models. Temperatures above 65 km are substantially warmer in winter than in summer. Average seasonal temperature differences are about 40K at 80 km. They are very pronounced at midlatitudes (Wallops Island) and become even more extreme at high latitudes where in summer mesopause temperatures as low as 140K were observed. Maximum stratopause temperatures were observed during late winter-early summer. At Wallops Island these maxima of about 280K coincided with the period of transition from winter to summer circulation. Temperature profiles for all seasons at all sites intersect between 60 and 65 km at a temperature range of 230 to 240K.
The strong westerly flow in winter shows two pronounced cores, one persistent throughout the winter just above the stratopause, the other somewhat weaker and less persistent near 75 km. Deviations from the zonal flow indicate the existence of meteorological circulation cells on a synoptic scale with the average meridional flaw at Churchill strongly from the north during both summer and winter and at Wallops Island somewhat weaker from the south during the winter.
Abstract
A least squares regression method is formulated for obtaining global temperature and geopotential height profiles from satellite radiation measurements, particularly those obtained by the Sate1lite Infra-Red Spectrometer (SIRS) aboard the Nimbus 3 satellite launched Apr. 14, 1969. Regression equations relating temperature and geopotential height to spectral radiance observations are derived. A method accounting for the influence of clouds, mountains, and hot terrain on the solutions is described. Results obtained from Nimbus 3 radiance data are presented.
The procedure described herein has been successfully applied to Nimbus 3 SIRS observations on a real-time basis. The temperature and geopotential heights obtained are being used operationally by the National Meteorological Center in their objective constant pressure analyses. Numerous meteorological results are given to demonstrate the usefulness of this new sounding tool.
Abstract
A least squares regression method is formulated for obtaining global temperature and geopotential height profiles from satellite radiation measurements, particularly those obtained by the Sate1lite Infra-Red Spectrometer (SIRS) aboard the Nimbus 3 satellite launched Apr. 14, 1969. Regression equations relating temperature and geopotential height to spectral radiance observations are derived. A method accounting for the influence of clouds, mountains, and hot terrain on the solutions is described. Results obtained from Nimbus 3 radiance data are presented.
The procedure described herein has been successfully applied to Nimbus 3 SIRS observations on a real-time basis. The temperature and geopotential heights obtained are being used operationally by the National Meteorological Center in their objective constant pressure analyses. Numerous meteorological results are given to demonstrate the usefulness of this new sounding tool.
