Weather Radar Technology Beyond NEXRAD (2002) / Chapter Skim
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4. Networks and Mobile Platforms
4. Networks and Mobile Platforms
Pages 36-45
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From page 36... ...
Although the NEXRAD network was originally envisioned as an integral part of a complex and comprehensive integrated system in the modernized weather service, fully comprehensive integration of the radar information with other observational data in sophisticated interpretive algorithms and in data assimilation schemes with numerical models has yet to be realized. Much developmental work of this nature will certainly continue in the years to come, and weather forecasts will certainly be improved as a consequence of the NEXRAD data.
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From page 37... ...
In particular, polarimetric X-band systems can possibly measure hydrologically and climatologically important light to moderate rainfall more accurately than is possible with S-band systems (Martner et al., 2001~. These radars may also be useful in detecting conditions in clouds prior to the onset of lightning where electric fields align crystals vertically, leading to regions of negative differential phase shift that are readily detected by polarimetric radars (Caylor and Chandrasekar, 1996; Carey and Rutledge, 1998~.
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From page 38... ...
Therefore, the use of extensive networking to integrate large S-band phased array systems with smaller, short-range, short-wavelength radar, along with implementation of attenuation correction, could solve two critical problems of current-day systems. Specifically, the near-surface boundary layer coverage would be more uniform, and polarimetric capability would allow improved rainfall estimation at lower rain rates.
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From page 39... ...
nation provide superb low-level coverage in areas often not covered as well by the NEXRAD. There are also more than 100 weather radars operated by private sector organizations, primarily television stations that also could provide useful data.
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From page 40... ...
Polar orbiting satellite data are valuable in numerical weather prediction, and geostationary satellite data provide continuous images of clouds, water vapor, temperature, and other variables along with wind data. The increasing availability and sophistication of digital photographic and video equipment, coupled with the emphasis on increasing the data transmission bandwidth available to nearly everyone, means that a wide variety of visual imagery provided by amateurs as well as professionals may play a role in the future observing system.
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From page 41... ...
Data from mobile radar networks could be used to determine more accurately the boundary layer wind field so that nowcasts and forecasts of surface wind speeds could be improved. Ad hoc mobile Doppler radar networks could also be used near and downwind from sites of nuclear, biological, chemical, and other accidents or acts of
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From page 42... ...
While mobile, short-wavelength radars could be used for special purposes in limited areas, transportable NEXRAD replacements could be used near NEXRAD sites at which the local network operational radars are not working for extended periods of time. Recommendation Near-Term The potential of operational mobile radar systems to contribute to the nat~on's weather surveillance system for emergency response and for improved shortterm forecasts should be evaluated.
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From page 43... ...
of the winds above the surface. Recommendation Visionary The capabilities of Unmanned Aerospace Vehicles and piloted aircraft to carry weather radar payloads should be monitored for their potential to provide weather surveillance over the continental United States and over the oceans.
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From page 44... ...
Also, the long intervals between successive observations limit the utility of space-borne observations for weather prediction. In addition to providing rainfall measurements, TRMM has also provided high quality measurements of the ocean surface cross section; the latter are also well related to the near surface winds.
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From page 45... ...
The use of scatterometer observations in data assimilation systems can extend their usefulness substantially and lead to improved sea level pressure analyses, improved upper air analyses of both wind and geopotential, and improved short and extended-range numerical weather forecasts. Typically, forecast improvements are skewed toward the Southern Hemisphere extratropics, with the length of a useful forecast extended by as much as 24 h in some Data Assimilation Systems.
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