GPM Constellation
Image Caption
Illustration of the multiple precipitation measurement satellites which comprise the GPM constellation.
(updated 1/13/14)
Arlene Is First 2011 Atlantic Tropical Storm
The National Hurricane Center (NHC) named Tropical Storm Arlene the first tropical storm of the 2011 Atlantic hurricane season on 29 June 2011 at 0000 UTC (7 PM CDT). The TRMM satellite had a good look at Arlene when it passed above on 29 June 2011 at 0502 UTC (0:02 AM CDT). At that time Arlene's winds were estimated to be about 34 knots (~39 mph) indicating that it was barely a tropical storm. TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) data were used in the analysis on the upper left and show that Arlene was getting better organized and contained scattered heavy thunderstorms
TRMM Sees Arlene Threatening Mexico
The TRMM satellite again flew over tropical storm Arlene on 30 June 2011 at 0408 UTC before the first tropical storm of the Atlantic hurricane season came ashore in Mexico. Arlene had become a strong tropical storm with sustained winds of about 55 kts (~63 mph). The rainfall analysis above is from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR). It shows that Arlene contained areas of very heavy rainfall. A few rain showers from Arlene were starting to reach Mexico and extreme southern Texas but at that time the most intense storms were still located in the Gulf Of Mexico east of
Active and Passive Remote Sensing Diagram
Image Caption
This diagram illustrates the differences between active and passive remote sensing.
TRMM and GPM rely on active and passive instruments to measure the properties of precipitation from space.
Active radars, such as the TRMM Precipitation Radar, transmit and receive signals reflected back to the radar. The signal returned to the radar receiver (called radar reflectivity) provides a measure of the size and number of rain/snow drops at multiple vertical layers in the cloud (Left figure).
TRMM Monitors Southern Mexico's Rainfall
The TRMM satellite flew over an area of disturbed weather labeled 95L affecting southern Mexico on 27 June 2011 at 2148 UTC (5:48 PM EDT). The TRMM rainfall analysis shown above used TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) data. It shows that heavy rainfall of over 50mm (~2 inches) associated with 95L was occurring in southern Mexico northwest of Veracruz and over the Yucatan Peninsula. Some of this very heavy rainfall may result in flash flooding and mudslides. The National Hurricane Center (NHC) is watching this area and has indicated that there is a slight chance that a