Spatial Analysis of Rainfall Extent and Intensity Patterns in Tropical Cyclones Affecting Madagascar and Mozambique

Authors: Sarah VanSchoick*, University of Florida/Santa Fe College, Corene J Matyas, University of Florida
Topics: Climatology and Meteorology, Geographic Information Science and Systems, Hazards, Risks, and Disasters
Keywords: GIS, spatial analysis, tropical cyclones, climatology, rainfall, Madagascar, Mozambique, Southwest Indian Ocean, storms, TRMM
Session Type: Poster
Day: 4/4/2019
Start / End Time: 8:00 AM / 9:40 AM
Room: Lincoln 2, Marriott, Exhibition Level
Presentation File: No File Uploaded

Tropical cyclones (TCs) that make landfall over the coasts of Madagascar and Mozambique can cause flooding that endangers the livelihoods and lives of residents. The goals of this study were to examine rainfall extent of TCs that originate over the Southwest Indian Ocean (SWIO) to determine the timing of rainfall arrival prior to the passage of the storm center and whether a relationship exists between storm intensity and rainfall extent. Intensity data were retrieved from the International Best Track Archive for Climate Stewardship and rain rates were acquired through the Tropical Rainfall Measuring Mission dataset available 1998-2015. Using a Geographic Information System (GIS), the 3-hourly rain rates were contoured and regions enclosing 1 mm/hr were converted into polygons. The extent of the polygons were measured in one-degree increments around the storm center and average values were calculated for each quadrant (NW, NE, SW, SE). TCs were categorized by origin and path. Preliminary testing showed a statistically significant difference between the largest extent in each quadrant(p=.048 and p=.002). However, these differences have been attributed to the TRMM raster rainfall data recorded in pixels >20 km while differences in km between observations was only ~20km. Results also show that storms originating over the SWIO are larger in average extent (F(1, 3110)= 3.95, p=.047) and more intense in wind speed (F(1, 3004)= 17.719, p=.000) than storms originating over the Mozambique Channel. Future work will include analyzing environmental factors, increasing the database, and continuing the analysis of differences between SWIO and MC storms.

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