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Brittany is a senior studying Environmental Engineering at Colorado State University. She spent her summer with us working with Professor Thomas Vonder Haar and mentors John Forsythe and Janice Bytheway analyzing precipitable water.

The NASA Water Vapor Project (NVAP) has been creating a daily water vapor dataset spanning 1987-2010.  One device used to collect the total precipitable water (TPW) data is the Special Sensor Microwave/Imager (SSM/I).  The SSM/I is most accurate when collecting TPW data over oceans. Land contamination is a large source of error when using SSM/I, so a landmask is used to run data through to filter the land out. Therefore, it is critical to test the accuracy of the SSM/I.

Global Positioning System (GPS) is being used to interpret the more globally available SSM/I satellites. Data from three SSM/I satellites (F13, F14, and F15) and GPS receivers from January 2003 were used in this analysis. The SSM/I data was matched to GPS stations based on location and the time the data was collected.  This ensured that the TPW data being compared was from the same time and place. The GPS TPW was plotted against the SSM/I TPW to analyze the accuracy of the SSM/I readings. Then GPS island stations were isolated with a landmask and used as the source of SSM/I comparison as well.

The relationship between the GPS and SSM/I data was found to be linear with some scatter.  SSM/I F15 has a greater problem with scatter and most of those problem stations were found to be in Japan.  There is still error involved with SSM/I water vapor data.  A better understanding of water vapor will help with creating more accurate hydrological, weather and climate models in the future.

Brittany's summer research poster, Comparing and Analyzing Total Precipitable Water from Ground-Based GPS and SSM/I Satellite Remote Sensing, may be downloaded here (5MB). Brittany's research interests include severe storms, mesoscale meteorology and remote sensing. She enjoys drawing, reading fiction, gardening and hiking.

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