Engineering topics

Meyer, P. J.

Publications and source records attributed to Meyer, P. J..

7 records

NASA NTRS1994

Survey of visualization and analysis tools

A large number of commercially available visualization and analysis tools are available to the researcher. Some of the strengths and limitations of some of these tools, from the viewpoint of the earth sciences discipline, are discussed. Visualization and analysis tools fall into one of two categories: those that are designed to a specific purpose and are non-extensive and those that are generic visual programming tools that are extensible. Most of the extensible packages examined incorporate a data flow paradigm.

Meyer, P. J.↗

NASA NTRS1993

A browse facility for Earth science remote sensing data: Center director's discretionary fund final report

An image data visual browse facility is developed for a UNIX platform using the X Windows 11 system. It allows one to visually examine reduced resolution image data to determine which data are applicable for further research. Links with a relational data base manager then allow one to extract not only the full resolution image data, but any other ancillary data related to the case study. Various techniques are examined for compression of the image data in order to reduce data storage requirements and time necessary to transmit the data on the internet. Data used were from the WetNet project.

Meyer, P. J.↗

NASA NTRS1986

An analysis of mesoscale VAS retrievals using statistical structure functions

Mesoscale sounding data from a truth rawinsonde network and a VAS from March 6-7, 1982 are statistically studied. The parameters of temperature, geopotential height, and mixing ratio at 850, 700, 500, 300, and 200 mb levels, and thickness and precipitable water are examined. The VAS retrieval gradients derived from a physical algorithm and from a regression technique are analyzed; the analysis reveals that both techniques have similar error characteristics and capabilities for calculating gradients of mesoscale temperature and geopotential height. Ground-truth rawinsonde data and VAS retrievals are compared; it is observed that VAS data describes weaker gradients than rawinsonde data.

Fuelberg, H. E.↗

NASA NTRS1985

Application of the Man-computer Interactive Data Access System (McIDAS) to aerospace meteorology

The Man-computer Interactive Data Access System (McIDAS) considered in this paper has been in use at Marshall Space Flight Center (MSFC) since 1981. The MSFC McIDAS system is primarily employed as a research tool, taking into account rainfall estimates as deduced from Scanning Multichannel Microwave Radiometer (SMMR) data, remote sensing sensor development (MAMS), Doppler-lidar derived winds, cloud tracked winds, and analysis of lightning ground strike data. With respect to the SMMR data analysis, passive microwave satellite data are displayed on McIDAS as images. Two major research efforts are concerned with the determination of mesoscale winds. These efforts are based on a utilization of a Doppler-lidar system, and GOES multispectral imagery. It is pointed out that future plans include increased usage of the McIDAS system.

Meyer, P. J.↗

NASA NTRS1984

Statistical structure of convective periods derived from satellite ground based data

The documentation of characteristics of Vertical Atmospheric Soundings (VAS) through the use of statistical structure and correlation functions is presented. A measure of random error is also provided. Rawinsonde data from various periods is analyzed. Structure and correlation functions are used to compare VAS retrievals obtained using a physical algorithm with those from a regression technique. Results from both procedures are evaluated against those from a mesoscale network of rawinsonde stations. The parameters documented include temperature, mixing ratio, geopotential height, thickness, and precipitable water. Calculation are performed at several layers in the lower and upper troposphere.

Meyer, P. J.↗

NASA NTRS1984

An analysis of the AVE-SESAME I period using statistical structure and correlation functions

Structure and correlation functions are used to describe atmospheric variability during the 10-11 April day of AVE-SESAME 1979 that coincided with the Red River Valley tornado outbreak. The special mesoscale rawinsonde data are employed in calculations involving temperature, geopotential height, horizontal wind speed and mixing ratio. Functional analyses are performed in both the lower and upper troposphere for the composite 24 h experiment period and at individual 3 h observation times. Results show that mesoscale features are prominent during the composite period. Fields of mixing ratio and horizontal wind speed exhibit the greatest amounts of small-scale variance, whereas temperature and geopotential height contain the least. Results for the nine individual times show that small-scale variance is greatest during the convective outbreak. The functions also are used to estimate random errors in the rawinsonde data. Finally, sensitivity analyses are presented to quantify confidence limits of the structure functions.

Fuelberg, H. E.↗

NASA NTRS1984

Structure function analyses of mesoscale VAS retrievals

Structure function analyses are used for a comparison of two VAS retrieval procedures, one obtained using a physical inversion technique and the other from a linear regression technique. Results from both procedures are evaluated and compared with those from a special mesoscale network of radiosonde stations, operated during March 6, 7, 1982 as part of the AVE-VAS field experiment. It is shown that both types of VAS retrievals underestimate the magnitudes of mean nondirectional gradients that are detected by the mesoscale radiosonde network. This result is expected since the VAS provides a volumetric sample of the atmosphere.

Meyer, P. J.↗