BHUBANESWAR: Researchers from IIT Bhubaneswar have found a more effective way of predicting monsoon depression and associated rainfall in the Bay of Bengal (BoB). The first-of-its-kind study is expected to help weathermen in studying the disorganised systems more accurately and help the state in efficient water and flood management.
The research paper called ‘Investigating the precipitation features of monsoon deep depression over the Bay of Bengal using high-resolution standalone and coupled simulations’, published in the quarterly journal of Royal Meteorological Society suggests the Ocean Atmosphere Wave Sediment Transport (COAWST) model, also known as coupled model, is more effective than the Weather Research and Forecasting (WRF) or standalone atmospheric model, widely used by different agencies including IMD, in forecasting monsoon depression, deep depression, their track and the intensity of the associated rainfall in real time.
“We found that COAWST -- that takes both ocean and atmosphere interaction into account to forecast track and intensity of the monsoon systems such as depression and deep depression -- is capable of predicting the track with 12 per cent more accuracy and intensity with 17 per cent more accuracy over the WRF model,” said associate professor in the School of Earth, Ocean and Climate Sciences at IIT Bhubaneswar Sandeep Pattnaik.
One of the authors of the research paper, Prof Pattnaik said the coupled model was found to be more useful in analysing the characteristics of rain making process of the system compared to the standalone atmospheric model. “Rain making involves study of moisture/humidity contribution and cloud contribution. In coupled simulation, we found contribution of moisture is more compared to cloud in rain making process of the depression formed over Bay of Bengal during monsoon. As coupled model helps in better representation of the moisture contribution, it helps in better prediction of the rain compared to the WRF modal that majorly studies cloud contribution,” he said.
Besides, Prof Pattnaik said, vertical advection -- the process through which moisture and heat is transferred from the surface to the upper part of the atmosphere where cloud formation takes place in the storm core regions, a crucial component of the rain making process - is better represented in the coupled atmosphere-ocean model.
“These rain features are better predicted by the coupled model due to better air-sea interactions and realistic representation of vertical structure of atmospheric parameters. If done in a real time basis, the model will be more useful and productive in weather forecast and help government in water management dam management and agriculture,” he said. Chakraborty Tapajyoti and Baisya Himadri from the School of Earth, Ocean and Climate Sciences are the other two authors of the research work.
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