Search Results

You are looking at 1 - 10 of 14 items for

  • Author or Editor: James F. W. Purdom x
  • Refine by Access: All Content x
Clear All Modify Search
James F. W. Purdom

Abstract

The high-resolution satellite imagery presently available from the Geostationary Operational Environmental Satellite (GOES) gives us a unique view of convective activity. This paper addresses some of the mesoscale phenomena, revealed in both pictures from GOES and in movies made from those pictures, which are important in the initiation and maintenance of convection. Specific attention is given to the organization of convection into lines and the importance of those convective lines in subsequent thunderstorm formation. The place where two convective lines merge almost invariably marks the location of intense convective development; under the right conditions, that activity will be severe.

Full access
JAMES F. W. PURDOM

Abstract

No Abstract Available.

Full access
John F. Weaver and James F. W. Purdom

Abstract

Satellite images are presented to illustrate an interesting interaction that occurred between a severe thunderstorm and a mesoscale feature that originated in its nearby environment. Immediately following that interaction, a series of tornadoes began, starting with a long-lived F5 tornado that produced major damage in Hesston, Kansas. Some speculation is presented regarding the physical processes that may have contributed to the observed changes in thunderstorm behavior.

Full access
Donald W. Hillger and James F. W. Purdom

Abstract

Clustering is used to enhance mesoscale meteorological detail in retrievals produced from satellite sounding measurements. By placing sounding fields-of-view (FOVs) into groups of similar measurements, mesoscale details are reinforced, compared to arbitrary grouping of FOVs into a fixed block size. Clustering takes advantage of similarity among the measurements to avoid smearing gradient information. A case study is presented showing the advantage of clustering as applied to the satellite sounding problem.

Full access
W. Paul Menzel and James F. W. Purdom

In the spring of 1994, the first of the National Oceanic and Atmospheric Administration's (NOAA's) next generation of geostationary satellites, GOES-I, is scheduled for launch. The introduction of this major component of NOAA's modernization represents a significant advance in geostationary remote sensing. All major components of the GOES-I system are new or greatly improved: 1) the satellite is earth oriented to improve instrument performance; 2) sounding and imaging operations are now performed by different and separate instruments; 3) a five-band multispectral radiometer with higher spatial resolution improves imaging capabilities; 4) a sounder with higher radiometric sensitivity enables operational temperature and moisture profile retrieval from geostationary altitude for the first time; 5) a different data format is used to retransmit raw data to directreceive users; and 6) a new ground data processing system handles the high data volume and distributes advanced products to a variety of users.

This article describes the features of the GOES-I spacecraft and instruments, imaging and sounding schedules, data handling systems, and remote sensing products. Simulations of GOES-I imager and sounder products are presented and compared with GOES-7 products. The simulations show that GOES-I imagery, derived product images, and sounder products should be significant improvements in both frequency of coverage and accuracy.

Full access
Carl E. Weiss and James F. W. Purdom

Abstract

No abstract available.

Full access
John F. Weaver, James F. W. Purdom, and Timothy L. Schneider

Abstract

Blackbody radiation at 3.9 µm increases rapidly with temperature. This fact suggests a potential application by fire weather meteorologists of the 3.9-µm imagery data provided by the new GOES-8 weather satellite. The ability of the 3.9-µm channel to sense forest fires is briefly discussed and an example case study is presented. A simple radiation model is used to estimate the minimum detectable fire size for several types of wildfires.

Full access
John F. Weaver, James F. W. Purdom, and Edward J. Szoke

Abstract

During the late afternoon and early evening of 6 June 1990, a series of severe thunderstorms produced nine tornadoes and numerous incidents of large hail on the High Plains of eastern Colorado. While the morning synoptic data clearly indicated a severe threat over the entire eastern half of the state, the severe activity that did occur was much more localized. Significant events were confined to a relatively small geographical region east and southeast of Denver, Colorado, including the small town of Limon some 70 miles to its southeast.

Satellite, radar, surface, and upper-air data are combined in this paper to study some of the mesoscale aspects of the severe storm environment. Results show that thunderstorm outflow from a large mesoscale convective system in Kansas and Nebraska played a crucial role in focusing the severe activity in eastern Colorado. Also, the evolution of convective development during the early part of the day suggested the presence of a sharp moisture gradient along the Front Range of the Rocky Mountains, which further helped to localize the outbreak. Finally, interactions between individual storms appear to have been critical to severe storm evolution.

Full access
Debra A. Molenar, Kevin J. Schrab, and James F. W. Purdom

The Regional and Mesoscale Meteorology (RAMM) Advanced Meteorological Satellite Demonstration and Interpretation System (RAMSDIS) was developed as part of an effort to get high quality digital satellite data to field forecasters prior to the deployment of the satellite component of the National Weather Service (NWS) Modernization Program. RAMSDIS was created by the National Oceanic and Atmospheric Administration (NOAA) National Environmental Satellite, Data and Information Service RAMM Team. RAMSDIS has made significant contributions to NOAA's satellite training and technology transfer program. The project has had a major impact on the utilization of digital satellite data, both nationally and internationally, providing the sole source for high-resolution digital satellite data at some NWS Forecast Offices (FOs) since 1993. In addition to its use in the FO, RAMSDIS has also provided data distribution and research capabilities on a common platform to several NOAA laboratories, allowing for more efficient collaboration on digital satellite data applications and analysis tools, and has been used by the World Meteorological Organization in an effort to provide digital satellite data to developing countries in Central America and the Caribbean.

The RAMSDIS project was innovative for many reasons. This article describes the unique approaches that made the project a success and details RAMSDIS utilization within the NWS and NOAA. The next phase of RAMSDIS implementation in the international meteorological community is also described.

Full access
John Weaver, James F. W. Purdom, and Stephan B. Smith

Abstract

No abstract available

Full access