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At least 649 records · Page 36

A study of Stormsat interactive data analysis facility

Stormsat, a third generation geosynchronous satellite intended for the investigation and forecasting of severe local storms, tropical cyclones and other mesoscale phenomena, could be launched as early as 1982. The paper outlines the interactive data processing and analysis functions which must be performed and presents a possible configuration capable of achieving the demonstration forecast objectives. Important features of the data processing system include (1) interactive extraction of wind, temperature and moisture profiles, cloud structure and precipitation from Stormsat data, and (2) numerical and statistical modeling necessary to provide demonstration forecasts.

Hasler, A. F.↗

The use of satellite estimates of rainfall in the initialization of a mesoscale hurricane model

The use of rainfall rate data obtained from satellites to improve the initial specification of the hurricane circulation is discussed with particular reference to the techniques for incorporating rainfall data into high-resolution hurricane models. The variation of latent heating in a numerical model of a steady state tropical cyclone is considered to ascertain what features of the storm motion can be deduced from a given field of latent heat release. A real-data example involving a mesoscale model for hurricane Eloise (1975) has demonstrated that satellite measurements of rainfall may be beneficial to numerical hurricane prediction.

Fiorino, M.↗

Data registration and integration requirements for severe storms research

Severe storms research is characterized by temporal scales ranging from minutes (for thunderstorms and tornadoes) to hours (for hurricanes and extra-tropical cyclones). Spatial scales range from tens to hundreds of kilometers. Sources of observational data include a variety of ground based and satellite systems. Requirements for registration and intercomparison of data from these various sources are examined and the potential for operational forecasting application of techniques resulting from the research is discussed. The sensor characteristics and processing procedures relating to the overlay and integrated analysis of satellite and surface observations for severe storms research are reviewed.

Dalton, J. T.↗

Thermal structure and dynamics of the Jovian atmosphere. I - The Great Red Spot

Temperatures and thermal winds over the Great Red Spot (GRS) are derived from Voyager IRIS data for atmospheric pressures between 3 and 500 mbar. A cold tropopause implies a decrease in anticyclonic vorticity with height above 500 mbar through the lower stratosphere. Observations at 5 microns indicate that there is little emission from the GRS itself, although there is enhanced emission from a ring around it. The behavior of the tropopause and 5 micron temperatures are considered to be results of circulation which rises within the GRS and subsides in the area around it. Results are discussed in the context of several theoretical models of the GRS, and latent heat release as an energy source is considered. Dynamical scalings based on an axisymmetric frictionally controlled vortex indicate that the large-scale dynamics of the GRS are linear, as opposed to those of a tropical cyclone which are nonlinear.

Flasar, F. M.↗

Future research contributions of the VAS

The VAS data which are used for studying and predicting numerous meteorological phenomena are discussed. These phenomena include severe local storm antecedent conditions, the formative stages of tropical cyclones, the definition of upper tropospheric circulation features, and as input to synoptic scale prediction models.

Shenk, W. E.↗

Hydrologic forecasting requirements for precipitation data from space measurements

The needs for precipitation information in severe storms research and in the operational detection and forecasting of such phenomena are described. The discussion will include thunderstorms, tropical cyclones, and regional and mesoscale numerical models used to analyze and forecast these and other regional scale phenomena.

Hudlow, M. D.↗

Stereoscopic observations of hurricanes and tornadic thunderstorms from geosynchronous satellites

Results are presented which show the application of GOES stereoscopy to the investigation of hurricanes and tornadic thunderstorms. Stereo cloud top height contour maps were constructed to observe the structural evolution of two hurricanes, Frederic on September 12, 1979 and Allen on August 8, 1980, and a tornadic thunderstorm complex over Oklahoma on May 2-3, 1979. Stereo height contours of Hurricane Allen reveal a very intense and symmetric storm with a circular shaped central dense overcast with an average height of 16.5 km. Contours of Hurricane Frederic reveal a preferred region for convection with an explosive exhaust tower attaining a maximum height of 17.8 km. Also presented is a technique for estimating tropical cyclone intensity using GOES stereo height and IR temperature information. Results indicate vertical motions ranging from 4.4 m/s for a moderate storm to 7.7 m/s for an intense storm.

Mack, R.↗

Kinematic analysis of Hurricane Frederick (1979) using satellite, aircraft and Rawinsonde data

Results of kinematic analyses of Hurricane Frederick (1979) performed using satellite wind vectors, aircraft measurements and rawinsonde data are presented. The data were gathered, reduced, preliminarily integrated and used to analyze the structure of the storm in the inflow and outflow layers. The mean structure at large radii is in good agreement with composite analyses of tropical cyclones. Changes in the storm structure from 11 to 12 Sep. 1979 suggest that remote sensing techniques are useful in monitoring storm intensity. A more sophisticated integration of the various data, including determination of optimum heights for satellite wind vectors, is underway.

Frank, W. M.↗

Genesis of tornadoes associated with hurricanes

The climatological history of hurricane-tornadoes is brought up to date through 1982. Most of the tornadoes either form near the center of the hurricane, from the outer edge of the eyewall outward, or in an area between north and east-southeast of the hurricane center. The blackbody temperatures of the cloud tops which were analyzed for several hurricane-tornadoes that formed in the years 1974, 1975, and 1979, did not furnish strong precursor signals of tornado formation, but followed one of two patterns: either the temperatures were very low, or the tornado formed in areas of strong temperature gradients. Tornadoes with tropical cyclones most frequently occur at 1200-1800 LST, and although most are relatively weak, they can reach the F3 intensity level. Most form in association with the outer rainbands of the hurricane.

Gentry, R. C.↗

Kinematic analysis of Hurricane Frederick (1979) using satellite, aircraft and rawinsonde data

Results of kinematic analyses of Hurricane Frederick (1979) performed using satellite wind vectors, aircraft measurements and rawinsonde data are presented. The data were gathered, reduced, preliminarily integrated and used to analyze the structure of the storm in the inflow and outflow layers. The mean structure at large radii is in good agreement with composite analyses of tropical cyclones. Changes in the storm structure from 11 to 12 Sep. 1979 suggests that remote sensing techniques may be useful in monitoring storm intensity.

Frank, W. M.↗

NASA/NOAA/USAID implementation of the South Pacific severe storm detection and warning system project

Implementation by NASA of the South Pacific severe storm detection and warning system project for the Fiji Meteorological Service (FMS) in Nadi, Fiji, is discussed. A description of the need and use of the system by the FMS, of data reception, of interactive computer techniques, of training, and of the benefits to be derived from implementation of the system is given. The project allows precise tracking of all South Pacific tropical cyclones with frequent high-resolution reception of both the Japanese GMS and the U.S. GOES-West visible and IR cloud images.

Dodge, J.↗

Severe Storms Branch research report (April 1984 April 1985)

The Mesoscale Atmospheric Processes Research Program is a program of integrated studies which are to achieve an improved understanding of the basic behavior of the atmosphere through the use of remotely sensed data and space technology. The program consist of four elements: (1) special observations and analysis of mesoscale systems; (20 the development of quanitative algorithms to use remotely sensed observations; (3) the development of new observing systems; and (4) numerical modeling. The Severe Storms Branch objectives are the improvement of the understanding, diagnosis, and prediction of a wide range of atmospheric storms, which includes severe thunderstorms, tornadoes, flash floods, tropical cyclones, and winter snowstorms. The research often shed light upon various aspects of local weather, such as fog, sea breezes, air pollution, showers, and other products of nonsevere cumulus cloud clusters. The part of the program devoted to boundary layer processes, gust front interactions, and soil moisture detection from satellites gives insights into storm growth and behavior.

Dubach, L.↗

Hurricane structure and wind fields from stereoscopic and infrared satellite observations and radar data

Hurricane cloud and precipitation structure have been studied by means of IR and stereoscopic visual satellite data from synchronized scanning GOES-East and -West, in combination with ground-based radar data for Hurricane Frederico and time-composited airborne radar data for Hurricane Allen. It is noted that stereoscopically measured cloudtop height in these hurricanes is not as closely correlated to radar reflectivity at lower levels as it is in intense thunderstorms over land. This and other results obtained imply that satellite precipitation estimation techniques for tropical cyclones that are based on cloudtop measurements will not be accurate with respect to time and place scales that are less than several hours and a few hundred km, respectively.

Hasler, A. F.↗

Observation guidelines for a Total Ozone Mapping Spectrometer (TOMS) in geosynchronous orbit

The successful utilization of Total Ozone Mapping Spectrometer (TOMS) measurements in low Earth orbit for the analysis of rapidly changing events has led to the consideration of a TOMS in geosynchronous orbit. This orbit should allow for the selection of temporal and spatial resolutions that are specifically designed for these events, plus the flexibility of selecting different sized areas and pointing the sensor to focus on the most interesting events. Separate temporal and spatial resolution guidelines plus recommended areal coverage have been developed for tropical cyclones, jet streams, the interaction between strong convection and the environment, and the surveillance of volcanoes. It is also suggested that the most effective use of TOMS would be simultaneous flights with microwave and high spatial resolution infrared temperature profiles.

Shenk, William E.↗

Suggested severe local storm operational scenario for GOES I-M

The GOES I-M satellite system is expected to provide continuous high resolution estimates of temperature and moisture profiles, winds from cloud motions, surface temperature, cloud properties, and precipitation for severe local storm and tropical cyclone events. The suggested operational schedule for the GOES I-M satellite emphasizes the observation frequencies, spatial coverage, spectral bands, etc. for the GOES I-M imager and sounder instruments that are expected to optimize the determination of the relevant meteorological parameters. During severe local storm events, the imager would be programmed to perform high frequency imaging (less than or= 3.5 min) for determining winds from cloud motions and for monitoring severe convection. In addition, the sounder would provide temperature and moisture profiles every hour over a 3000 X 3000 km domain during the antecedent stage or over a 1000 X 1000 km area every 10 minutes during the mature storm stage.

Shenk, William E.↗

NASA follow-on on the Fiji South Pacific Severe Storm Warning System Project (SPSSD/WS)

The follow-on agreement will implement needed systems enhancements of the satellite ground station installed under the previous SPSSD/WS project. These enhancements include the purchase and installation of an Uninterruptible Power Supply (UPS) and lightning protection unit, hardware modifications to provide system redundancy and increased data storage capacity, software modifications for the new Japanese GMS digital data, upgrades of the image processing software, and both hardware maintenance and tropical cyclone analysis training, and a non-renewable grant to provide emergency field repairs and replacement/spare parts. In March 1988, the UPS and lightning protection unit was installed at the Fiji Meteorological Service by NASA personnel. A tape recorder and demodulator was shipped to Fiji to record the new digital GMS data. Data tapes are not yet available from the Japanese Meteorological Service of the new digital format. This data is required to test the GMS digital software being developed for the Fiji SPSSD/WS facility.

Vermillion, C.↗

Suggested GOES I-M satellite operational scenarios

Plans for the GOES I-M satellite system are reviewed, focusing on the use of GOES data in severe local storm and tropical cyclone analysis and forecasting. The instrumentation and capabilities of the GOES I-M system, which is expected to be launched beginning in the spring of 1990, are discussed. Sounder and imaging coverage scenarios and scenario timetables are presented.

Shenk, William E.↗