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High Frequency Microwave Observations of Frozen Hydrometeors. Gail Skofronick Jackson University of Maryland, Baltimore County, Goddard Earth Science and Technology Center Goddard, Code 975, gailsjackson@ieee.org James A. Weinman, James R. Wang NASA Goddard Space Flight Center, Code 975
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High Frequency Microwave Observations of Frozen Hydrometeors Gail Skofronick Jackson University of Maryland, Baltimore County, Goddard Earth Science and Technology Center Goddard, Code 975, gailsjackson@ieee.org James A. Weinman, James R. Wang NASA Goddard Space Flight Center, Code 975 Dong-Eon Chang Center for Earth Observing and Space Research George Mason University Fairfax, VA Skofronick-Jackson, Weinman, Wang, Chang
Challenges of GPM • Measure extratropical precipitation, much of which is light rain and snow.This is especially critical to support land hydrology. • Improve sampling of all types of precipitation, including snow. Skofronick-Jackson, Weinman, Wang, Chang
Motivation • What information regarding frozen hydrometeors and snowfall in the atmosphere can be obtained from high frequency microwave measurements? • Improve understanding of hydrometeor-radiometer-radar relationships • Heritage: Early work by A. T. C. Chang and J. R. Wang, (1992) using the Airborne Advanced Microwave Moisture Sounder (AMMS). Skofronick-Jackson, Weinman, Wang, Chang
Snowfall Obs. Over LandNew England experienced a significant blizzard on 3/6/01. The 85.5 GHz PCT responds mainly to snow on the ground that extends over Canada whereas the low 183+7 AMSU-B brightness temperatures coincide with reported snowfall at the time. SSM/I 85 GHz AMSU-B 183±7 GHz Skofronick-Jackson, Weinman, Wang, Chang
Not Just A Surface Feature(Left) repeat of 183+7 GHz AMSU-B data at 2301UTC on 3/5/01 and (Right) data from the same sensor at 1302 UTC on 3/6/0. Note that the low brightness temperatures (snowfall?) have moved eastward off shore. AMSU-B 183±7 GHz 14 Hours later Skofronick-Jackson, Weinman, Wang, Chang
Not Just a Surface Feature:WSI Radar Mosaic Note reduction of snowfall over VT. 05 March 2001 2300 06 March 2001 1300 Skofronick-Jackson, Weinman, Wang, Chang
MM5 Precipitation Distribution vs AMSU-B AMSU-B 183±7 GHz MM5 Precipitation Skofronick-Jackson, Weinman, Wang, Chang
Content and Weighting Fcns from MM5 Model of 3/6/01 Blizzard • Unlike the cloud-free case, these weighting functions are themselves function of the cloud distribution • Note order of magnitude increase in weighting function at high frequencies Skofronick-Jackson, Weinman, Wang, Chang
183 + 1 GHz AMSU-B 183 + 3 GHz AMSU-B Height Slicing using Water Vapor AbsorptionNote the absence of low brightness temperature concentrations over New England (left) and their presence (right). Skofronick-Jackson, Weinman, Wang, Chang
CAMEX-3 Observations EDOP (ER-2 Doppler Radar) Qualitative Profile Retrievals MIR (Millimeter-wave Imaging Radiometer) 89 - 340 GHz AMPR (Advanced Microwave Precipitation Radiometer) 10 – 85 GHz Skofronick-Jackson, Weinman, Wang, Chang
Microwave Weighting Functions for a Cirrus Anvil CaseNote that unlike the cloud-free case, these weighting functions are themselves a function of the cloud distribution Skofronick-Jackson, Weinman, Wang, Chang
Retrieval Results for Two Anvil Profiles using SelectedChannel Sets Skofronick-Jackson, Weinman, Wang, Chang
Conclusions/Summary • HF microwave channels reveal ice and snow features missed at TMI frequencies. • Snowfall appears observable from HF where water vapor absorption obscures the ground and may reveal ice profiles. Skofronick-Jackson, Weinman, Wang, Chang