Passive Microwave Brightness Temperatures as Proxies for Hailstorms

• Published in: Journal of applied meteorology and climatology Vol. 48; no. 6; pp. 1281 - 1286
• Main Author: Cecil, Daniel J.
• Format: Journal Article
• Language: English
• Published: Boston, MA American Meteorological Society 01.06.2009
• Subjects: Archives & records; Brightness; Brightness temperature; Earth, ocean, space; Environmental conditions; Exact sciences and technology; External geophysics; Extreme values; Geophysics. Techniques, methods, instrumentation and models; Graupel; Hail; Hailstorms; Large hail; Lightning; Local minimum; Meteorological satellites; Meteorology; Microwaves; NOTES AND CORRESPONDENCE; Precipitation; Radar; Radar echoes; Radar reflectivity; Rain; Rainfall; Reflectance; Snow; Storms; Storms, hurricanes, tornadoes, thunderstorms; Surface radiation temperature; Temperature; Thunderstorms; TRMM satellite; Tropical rainfall; Tropical Rainfall Measuring Mission (TRMM); Updraft; Weather; United States > US; Passive detection; Weather forecast; Proxy; brightness temperature; Severe weather; Space remote sensing; Satellite observation; Microwave radiometry; TRMM satellite; Hail; storms; Microwave imaging
• DOI: 10.1175/2009jamc2125.1
• ISSN: 1558-8424

The Tropical Rainfall Measuring Mission (TRMM) satellite has been used to infer distributions of intense thunderstorms. Besides the lightning measurements from TRMM, the radar reflectivities and passive microwave brightness temperatures have been used as proxies for convective vigor. This is based on large graupel or hail lofted by strong updrafts being the cause of high–radar reflectivity values aloft and extremely low brightness temperatures. This paper seeks to empirically confirm that extremely low brightness temperatures are often accompanied by large hail at the surface. The three frequencies examined (85, 37, and 19GHz) all show an increasing likelihood of hail reports with decreasing brightness temperature. Quantification is limited by the sparsity of hail reports. Hail reports are common when brightness temperatures are below 70 K at 85 GHz, 180 K at 37 GHz, or 230 K at 19 GHz.