Feature

Tropical Cyclone 03B Has Incredible Staying Power Over India
09.10.09
 
September 10, 2009

Tropical Cyclone 03B over India. > Click here to view the PDF file of Cylone 03B images
Image Credit:JPL, Ed Olsen
Tropical Cyclone 03B Has Incredible Staying Power Over India

A low that developed in the Bay of Bengal from the monsoon season last week and was briefly classified as a tropical cyclone, named TC 03B, made an inland trek into India and is still going. The storm's progression was captured by the Atmospheric Infrared Sounder (AIRS) and its accompanying Advanced Microwave Sounding Unit (AMSU) instruments on NASA's Aqua satellite as it developed over water and marched west from September 4-9, 2009.

TC 03B made landfall last weekend in West Bengal south of Kolkata, India and moved into the Indian state of Jharkhand.

The AMSU microwave images are created from the radiances of its 89 GHz channel, whereas the AIRS infrared images are created from the radiances of its 12 micron channel. Areas colder than 273 Kelvin or 32 degrees Fahrenheit (beginning at yellow and left-ward toward blue and violet) in the imagery indicate where the convection has driven the cloud tops high enough to contain ice. The colder the cloud tops, the higher they are and thus the stronger the convection. Thunderstorms and heavy rain are associated with these areas.

Those thunderstorms have been dropping between four and eight inches of rain over the cyclone track, with almost 10 inches reported at Bankura in West Bengal. As TC 03B has tracked farther inland into north-central India, those rain rates have remained consistent.

Meanwhile, the AIRS instrument provided valuable infrared data on TC 03B's cloud top temperatures. They're important because they tell forecasters how high the storm cells reach in the atmosphere and the higher the convective clouds, the more powerful the thunderstorms. The data allow forecasters to see where the strong thunderstorms occur in TC 03B's circulation.

In AIRS infrared imagery, NASA's false-colored purple clouds are as cold as or colder than 220 Kelvin or minus 63 degrees Fahrenheit (F). The blue colored clouds are about 240 Kelvin, or minus 27F. The colder the clouds are, the higher they are, and the more powerful the thunderstorms are that make up the cyclone. AIRS imagery even today, September 9, shows that 03B still had very cold thunderstorm cloud tops, indicating strong storms and heavy rainfall, despite the fact that the center of circulation has been inland for days.

Text Credit: Rob Gutro, NASA/Goddard Space Flight Center