Large Area Soil Moisture Variations in Response to Cyclone Phailin in Eastern India

In October 2013, a very severe cyclonic storm Phailin that originated from a remnant cyclonic circulation from the South China Sea progressed westward toward the Indian subcontinent and made its landfall in Gopalpur town of an eastern Indian state of Orissa. The landfall (on October 12, 2013) was followed by very heavy rainfall in the Indian states of Orissa, Andhra Pradesh, Chhattisgarh, Jharkhand, Bihar, and West Bengal, threatening floods in some of these states. In this letter, an attempt has been made to build up a correlation between in situ rainfall and soil moisture, which is retrieved using brightness temperature data from Advanced Microwave Scanning Radiometer 2 (AMSR2), for the cyclone period (October 10-16, 2013). Using brightness temperature as the forcing parameter, the land parameter retrieval model has been employed to retrieve soil moisture at 12 hourly intervals for the period October 10-16, 2013. The study reveals a good agreement between the variations of rainfall (cause) and soil moisture (response) with correlation coefficient greater than 0.6 and the sensitivity of AMSR2 brightness temperature to soil moisture variations.