1. GPM Planning Mtg Aug 2001Skofronick-Jackson, Weinman, Wang, Chang 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.orggailsjackson@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

2. GPM Planning Mtg Aug 2001Skofronick-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.

3. GPM Planning Mtg Aug 2001Skofronick-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).

4. GPM Planning Mtg Aug 2001Skofronick-Jackson, Weinman, Wang, Chang Snowfall Obs. Over Land New 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 GHzAMSU-B 183±7 GHz

5. GPM Planning Mtg Aug 2001Skofronick-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. 14 Hours laterAMSU-B 183±7 GHz

6. GPM Planning Mtg Aug 2001Skofronick-Jackson, Weinman, Wang, Chang Not Just a Surface Feature: WSI Radar Mosaic Note reduction of snowfall over VT. 05 March 2001 230006 March 2001 1300

7. GPM Planning Mtg Aug 2001Skofronick-Jackson, Weinman, Wang, Chang MM5 Precipitation Distribution vs AMSU-B AMSU-B 183±7 GHzMM5 Precipitation

8. GPM Planning Mtg Aug 2001Skofronick-Jackson, Weinman, Wang, Chang Content and Weighting Fcns from MM5 Model of 3/6/01 Blizzard 1)Unlike the cloud-free case, these weighting functions are themselves function of the cloud distribution 2)Note order of magnitude increase in weighting function at high frequencies

9. GPM Planning Mtg Aug 2001Skofronick-Jackson, Weinman, Wang, Chang Height Slicing using Water Vapor Absorption Note the absence of low brightness temperature concentrations over New England (left) and their presence (right). 183 + 1 GHz AMSU-B183 + 3 GHz AMSU-B

10. GPM Planning Mtg Aug 2001Skofronick-Jackson, Weinman, Wang, Chang CAMEX-3 Observations EDOP (ER-2 Doppler Radar) MIR (Millimeter-wave Imaging Radiometer) 89 - 340 GHz AMPR (Advanced Microwave Precipitation Radiometer) 10 – 85 GHz Qualitative Profile Retrievals

11. GPM Planning Mtg Aug 2001Skofronick-Jackson, Weinman, Wang, Chang Microwave Weighting Functions for a Cirrus Anvil Case Note that unlike the cloud-free case, these weighting functions are themselves a function of the cloud distribution

12. GPM Planning Mtg Aug 2001Skofronick-Jackson, Weinman, Wang, Chang Retrieval Results for Two Anvil Profiles using Selected Channel Sets

13. GPM Planning Mtg Aug 2001Skofronick-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.