The National Weather Service Modernization and Associated Restructuring by Committee on the Assessment of the National Weather Service’s Modernization Program

Author:Committee on the Assessment of the National Weather Service’s Modernization Program
Language: eng
Format: epub
Tags: ebook, book
Publisher: The National Academies Press
Published: 2012-11-26T00:00:00+00:00

FIGURE 4.2 (a) Composite pre-NEXRAD coverage at 10,000 feet above site level for CONUS is indicated by white circles. Radar locations are indicated by diamonds (WSR-57 and WSR-74S) and circles (WSR-74C). The pink shading indicates areas that have no radar coverage below 10,000 feet above site level. (b) Composite NEXRAD coverage at 10,000 feet above site level for CONUS is indicated by white circles. WSR-88D radar locations are indicated by + (National Weather Service radars) and × (Department of Defense radars). The pink shading indicates areas that have no radar coverage below 10,000 feet above site level. The striped blue shading indicates areas where coverage at the 10,000 feet level is reduced compared with the pre-NEXRAD network. SOURCE: U.S. Department of Commerce.

Satellite Upgrades

NOAA’s objectives for GOES-Next were continuous Earth-viewing with retention of the existing visible imaging, higher resolution infrared (IR) imagery, improved Earth location capabilities, and a separate sounder. Despite the difficulties in program design and execution, GOES-Next introduced substantial data and product improvements. On earlier geostationary satellites, the imager and sounder could not simultaneously collect data because they used the same telescopic viewing apparatus, and the spin-stabilized satellite rotated on its axis viewing Earth only six percent of the time on each 360-degree rotation (GAO, 1997c). Although the initial development of a three-axis, body-stabilized spacecraft design for GOES was problematic, it ultimately resulted in successful establishment of a valuable approach. These improvements together enabled continuous, simultaneous, independent imaging and sounding. Each instrument had flexible scan control, allowing for coverage of small areas, hemispheric, and full disk global scenes. Meteorologists were able to access close-up, continuous observations of dynamic, short-lived weather phenomena, such as local severe storms and tropical cyclones, as well as obtain data on the atmospheric temperature and water vapor structure.

The implementation of GOES-Next resulted in substantial improvements to the frequency, spatial resolution, data quality, and spectral resolution of NWS geostationary satellite data. Specific impact areas include

• Imagery. Due to the Earth-pointing capability of the GOES-Next satellite, the five-channel imager could produce imagery every 5 to 10 minutes for local-scale severe weather events and every 15 minutes for CONUS coverage, and scan the full disk northern hemisphere in less than 30 minutes (with images provided every 3 hours). The continuous viewing capability is critical for monitoring severe storms (GAO, 1991b). Improvements were made in the spectral resolution and signal-to-noise performance, as shown in Table 4.1. New uses of imager data were developed. For example, the data were combined with the NEXRAD radar data to enhance winter snowstorm forecasting, nighttime fog detection was enabled using two IR channels, and the higher resolution IR imagery was useful in predicting and monitoring severe thunderstorms. Additional results include

- best 6.7 μm (IR water vapor channel) imagery ever; an order of magnitude improvement enables identification of mesoscale disturbances embedded within synoptic scale features;

- better wind data inferred from cloud drift with 4 km image resolution for better edge detection and improved target selection;

- improved wind data inferred from water vapor imagery in clear regions with 8 km spatial resolution and better signal-to-noise at 6.

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