IMPACT OF EL NIÑO AND LA NIÑA ON SOIL MOISTURE- PRECIPITATION FEEDBACK OF INDIAN MONSOON OVER CENTRAL INDIA
- Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016, India
Keywords: El Niño, La Niña, Soil Moisture, Evapotranspiration, BATS, CLM
Abstract. The processes across an interface between land surface and the atmosphere over central India have a strong impact on the Indian summer monsoon climate, particularly during extreme years. The soil moisture-climate interactions, i.e. impacts on temperature and precipitation for years of excess (1999,2010) and deficit (1987,2009) rainfall over central India are being analyzed. For this study, two land surface parameterization schemes the Biosphere Atmosphere Transfer scheme (BATS) and the Community Land Model (CLM) were coupled using the regional climate model RegCM4.0. Soil moisture-temperature coupling and soil moisture-precipitation feedbacks are important land surface atmosphere interactions in context of climate change scenario. As feedbacks between land and atmosphere are hard to measure directly, correlation between temperature and evapotranspiration is the diagnostic used for assessing soil moisture-evapotranspiration-temperature coupling strength and simple statistic called "normalized feedback parameter" λNC of soil moisture and precipitation is used to access the strength of soil moisture precipitation feedback at a regional scale. The soil moisture – atmosphere coupling strength in BATS scheme coupled with RegCM4.0 is more than the coupling strength in the CLM scheme enabled with RegCM4.0. From our study it is validated that central India is the region in the Indian monsoon domain where profound soil moisture-climate interactions take place at a regional scale.