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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Broadcast media and the dissemination of weather information

Although television is the public's most preferred source of weather information, it fails to provide weather reports to those groups who seek the information early in the day and during the day. The result is that many people most often use radio as a source of information, yet preferring the medium of television. The public actively seeks weather information from both radio and TV stations, usually seeking information on current conditions and short range forecasts. forecasts. Nearly all broadcast stations surveyed were eager to air severe weather bulletins quickly and often. Interest in Nowcasting was high among radio and TV broadcasters, with a significant portion indicating a willingness to pay something for the service. However, interest among TV stations in increasing the number of daily reports was small.

Byrnes, J.↗
NASA NTRS1979

Interactions Between Convective Storms and Their Environment

The ways in which intense convective storms interact with their environment are considered for a number of specific severe storm situations. A physical model of subcloud wind fields and vertical wind profiles was developed to explain the often observed intensification of convective storms that move along or across thermal boundaries. A number of special, unusually dense, data sets were used to substantiate features of the model. GOES imagery was used in conjunction with objectively analyzed surface wind data to develop a nowcast technique that might be used to identify specific storm cells likely to become tornadic. It was shown that circulations associated with organized meso-alpha and meso-beta scale storm complexes may, on occasion, strongly modify tropospheric thermodynamic patterns and flow fields.

Maddox, R. A.↗
NASA NTRS1981

Weather and climate

Highlights of recent progress and the directions of future advances in the application of space observations to weather and climate are reviewed. In mesometeorology and severe storms, satellite stereography of cloud topography and temperature profiling from GOES-VAS promise dramatic developments in both nowcasting and prediction. In global weather, the initial results from the year long Global Weather Experiment conclusively demonstrate the enhanced forecast skill emanating from the use of satellite data, especially cloud track winds and temperature profiles. In climate, empirical studies and numerical experiments point to the feasibility of useful climate predictions on monthly and seasonal time scales. They also indicate the kinds of surface boundary conditions to which climate is sensitive and which need to be observed from space.

Atlas, D.↗
NASA NTRS1982

Efficient transfer of weather information to the pilot in flight

Efficient methods for providing weather information to the pilot in flight are summarized. Use of discrete communications channels in the aeronautical, VHF band or subcarriers in the VOR navigation band are considered the best possibilities. Data rates can be provided such that inputs to the ground based transmitters from 2400 band telephone lines are easily accommodated together with additional data. The crucial weather data considered for uplinking are identified as radar reflectivity patterns relating to precipitation, spherics data, hourly sequences, nowcasts, forecasts, cloud top heights with freezing and icing conditions, the critical weather map and satellite maps. NEXRAD, the ground based, Doppler weather radar which will produce an improved weather product also encourages use of an uplink to fully utilize its capability to improve air safety.

Mcfarland, R. H.↗
NASA NTRS1983

AVE/VAS experiment: Synoptic summary and preliminary results

The AVE/VAS ground truth field experiment was conducted during the Spring of 1982 severe storms and weather research program. The experiment consisted of acquiring correlative ground truth measurements of rawinsonde data, corresponding to the time and space resolutions of VAS sounding data. The objectives of the AVE/VAS experiment are: (1) to acquire four dimensional data sets of the actual atmospheric structure down to the mesoscale; (2) to provide measurements for quantitative comparisons between ground based and VAS-derived atmospheric parameters; (3) to evaluate the impact of VAS data on diagnostic analysis of structural features and dynamical processes important to the development of mesoscale phenomena; (4) to evaluate the impact of VAS data on numerical model simulations, nowcasting, and other mesoscale forecasting systems.

Jedlovec, G. J.↗
NASA NTRS1985

Real-time applications for remotely sensed lightning observations

Real-time monitoring of lightning activity, including the estimation of the location where the flash strikes the earth, provides a basis for the assessment of the impact of both the lightning hazard and severe weather on daily test and operation schedules. Applications to range meteorology are considered, taking into account the Space Transportation System, the handling of explosive materials, and test operations. Attention is given to details regarding forecasting and nowcasting, a low-cost lightning display system for electrical storm tracking and the support of lightning research activities, two versions of employed software, an example of the storm diagnostics and display products which will be available from the next generation weather radar, and a summary of the evolution of 12 New Mexico thunderstorms.

Goodman, S. J.↗
NASA NTRS1985

Mobile intercept of storms

The primary goal was to acquire lightning data to serve as ground truth for U2 overflights. Researchers were successful in instrumenting the Univ. of Mississippi/National Severe Storms Lab. (UM/NSSL) mobile laboratory and in coordinating storm intercept through communication to the U2 provided by airplane guidance at NSSL and through direct communication with the U2 pilot from a portable transceiver in the mobile lab. A demonstration showed that a mobile laboratory can be directed within a large geographical area and used to collect ground truth data for comparison with airborne data on a routine basis with proper utilization of forecasts, nowcasts, and communication among all participants. After the U2 flights, researchers turned their attention solely to intercepting severe storms within the area of Oklahoma with good Doppler radar coverage. They incorporated a second vehicle, which followed the mobile lab and from which they released instrumented balloons. This project utilized a standard meteorological rawinsonde and a balloon-borne electric field meter. They were successful in flying, tracking, and receiving data from mobily launched balloons on several days. Researchers believe that they have demonstrated the ability to obtain meteorological and electrical data in severe storms using instrumented balloons. This also includes the capability to launch into the mesocyclone region and for multiple launches in the same storm.

Arnold, R. T.↗
NASA NTRS1987

Toward operational forecasting and detection of weather-producing gravity waves

Detecting (or nowcasting) mesoscale gravity waves whose horizontal wavelengths are 200 km or more is discussed. Synthesis of bandpass-filtered synoptic barograph data with geostationary satellite imagery sequences can accomplish this goal in an operational environment, but only if changes to the operational data collection and transmission systems are made.

Koch, Steven E.↗
NASA NTRS1988

Special observations

The wind or temperature profiler is a new special observation device designed to supplement traditional atmospheric measurement and provide more accurate middle-range forecasts, including aviation and space applications. Radar is most useful in the short, nowcast time frame. Satellites and surface observations are also most useful for short-range forecasts but have less impact on the longer range. The radiosonde network, on the other hand, only starts to be very important after about six hours and has greatest impact at lead times of 12 hours or more. In the wind profiler, wind is measured by using clear-air Doppler radar principles, Two fixed beams, pointing 15 deg to the north and 15 deg to the east, sense the Doppler shift. The resulting wind vectors are then rotated to the horizontal and combined to give total wind. The temperature profiler measures temperature and humidity by using passive radiometers. Development on the profiler is 95 percent complete, and on the temperature profiler 75 percent complete.

Beran, Donald↗
NASA NTRS1989

A case study using kinematic quantities derived from a triangle of VHF Doppler wind profilers

Horizontal divergence, relative vorticity, kinematic vertical velocity, and geostrophic and ageostrophic winds are computed from Colorado profiler network data to investigate an upslope snowstorm in northeastern Colorado. Horizontal divergence and relative vorticity are computed using the Gauss and Stokes theorems, respectively. Kinematic vertical velocities are obtained from the surface to 9 km by vertically integrating the continuity equation. The geostrophic and ageostrophic winds are computed by applying a finite differencing technique to evaluate the derivatives in the horizontal equations of motion. Comparison of the synoptic-scale data with the profiler network data reveals that the two datasets are generally consistent. Also, the profiler-derived quantities exhibit coherent vertical and temporal patterns consistent with conceptual and theoretical flow fields of various meteorological phenomena. It is suggested that the profiler-derived quantities are of potential use to weather forecasters in that they enable the dynamic and kinematic interpretation of weather system structure to be made and thus have nowcasting and short-term forecasting value.

Carlson, Catherine A.↗
NASA NTRS1990

Continuous assimilation of simulated Geosat altimetric sea level into an eddy-resolving numerical ocean model. I - Sea level differences. II - Referenced sea level differences

The optimal interpolation method of Lorenc (1981) was used to conduct continuous assimilation of altimetric sea level differences from the simulated Geosat exact repeat mission (ERM) into a three-layer quasi-geostrophic eddy-resolving numerical ocean box model that simulates the statistics of mesoscale eddy activity in the western North Pacific. Assimilation was conducted continuously as the Geosat tracks appeared in simulated real time/space, with each track repeating every 17 days, but occurring at different times and locations within the 17-day period, as would have occurred in a realistic nowcast situation. This interpolation method was also used to conduct the assimilation of referenced altimetric sea level differences into the same model, performing the referencing of altimetric sea sevel differences by using the simulated sea level. The results of this dynamical interpolation procedure are compared with those of a statistical (i.e., optimum) interpolation procedure.

White, Warren B.↗
NASA NTRS1989

Use of the surface wind field as a predictor of thunderstorms and cloud-to-ground lightning at Kennedy Space Center

The convergence-lightning nowcasting method that began to be operationally tested and evaluated by USAF personnel at the KSC in 1986 uses surface convergence, especially the areal average, to identify the potential for new thunderstorm growth. When this areal method fails, normalized cell convergence, which is defined as the integral of cellular convergence with respect to its area, can be used as a complementary technique in association with the areal one. A detailed examination is conducted for one day, and the relationship of normalized cell convergence to lightning flash counts is examined in a 68-day ensemble.

Watson, Andrew I.↗
NASA NTRS1992

A plan for accurate estimation of daily area-mean rainfall during the CaPE experiment

The Convection and Precipitation/Electrification (CaPE) experiment took place in east central Florida from 8 July to 18 August, 1991. There were five research themes associated with CaPE. In broad terms they are: investigation of the evolution of the electric field in convective clouds, determination of meteorological and electrical conditions associated with lightning, development of mesoscale numerical forecasts (2-12 hr) and nowcasts (less than 2 hr) of convective initiation and remote estimation of rainfall. It is the last theme coupled with numerous raingage and streamgage measurements, satellite and aircraft remote sensing, radiosondes and other meteorological measurements in the atmospheric boundary layer that provide the basis for determining the hydrologic cycle for the CaPE experiment area. The largest component of the hydrologic cycle in this region is rainfall. An accurate determination of daily area-mean rainfall is important in correctly modeling its apportionment into runoff, infiltration and evapotranspiration. In order to achieve this goal a research plan was devised and initial analysis begun. The overall research plan is discussed with special emphasis placed on the adjustment of radar rainfall estimates to raingage rainfall.

Duchon, Claude E.↗
NASA NTRS1993

The importance of short-term forecasting of thunderstorms to launch operations at Cape Canaveral

The local meteorological events leading up to the launch of the space shuttle Atlantis on 2 August 1991 were captured in full-resolution GOES visible data being archived for the Convection and Precipitation/Electrification Experiment. The postponement of the launch on 1 August, and the successful lift-off on the following day provide a good example of the important role played by nowcasting and short-term forecasting at Cape Canaveral. In this brief article, we discuss the local weather conditions prior to, during, and after the launch and demonstrate the importance of short-term forecasting capabilities around the cape during launch operations.

Cooper, Harry J.↗
NASA NTRS1994

Analysis and prediction of ocean swell using instrumented buoys

During the period 20-23 September 1990, the remnants of Supertyphoon Flo moved into the central North Pacific Ocean with sustained wind speeds of 28 m/s. The strong wind and large fetch area associated with this storm generated long-period swell that propagated to the west coast of North America. National Data Buoy Center moored-buoy stations, located in a network that ranged from the Gulf of Alaska to the California Bight, provided wave spectral estimates of the swell from this storm. The greatest dominant wave periods measured were approximately 20-25 s, and significant wave heights measured ranged from 3 to 8 m. Wave spectra from an array of three nondirectional buoys are used to find the source of the long-period swell. Directional wave spectra from a heave-pitch-roll buoy are also used to make an independent estimate of the source of the swell. The ridge-line method, using time-frequency contour plots of wave spectral energy density, is used to determine the time of swell generation, which is used with the appropriate surface pressure analysis to infer the swell generation area. The diagnosed sources of the swell are also compared with nowcasts from the Global Spectral Ocean Wave Model of the Fleet Numerical Oceanography Center. A simple method of predicting the propagation of ocean swell, by applying a simple kinematic model of wave propagation to the estimated point and time source, is demonstrated.

Mettlach, Theodore↗
NASA NTRS1996

User's Manual for the Naval Interactive Data Analysis System-Climatologies (NIDAS-C), Version 2.0

This technical note provides the user's manual for the NIDAS-C system developed for the naval oceanographic office. NIDAS-C operates using numerous oceanographic data categories stored in an installed version of the Naval Environmental Operational Nowcast System (NEONS), a relational database management system (rdbms) which employs the ORACLE proprietary rdbms engine. Data management, configuration, and control functions for the supporting rdbms are performed externally. NIDAS-C stores and retrieves data to/from the rdbms but exercises no direct internal control over the rdbms or its configuration. Data is also ingested into the rdbms, for use by NIDAS-C, by external data acquisition processes. The data categories employed by NIDAS-C are as follows: Bathymetry - ocean depth at

USER M ANUALS↗