Abstrait

Atmospheric flowfield Simulations over a Tropical Coastal region Kalpakkam using the ARW Mesoscale Model

S.S.V.S.Ramakrishna, V.Lakshmana Rao,C.V.Srinivas N.Nagendra and 5K.B.R.R.Hariprasad

Field experimental observations from GPS Radiosonde, 3 meteorological towers and 16 automated weather stations were employed to validate boundary layer wind field simulations made with Weather Research and Forecasting (ARW) model in the tropical coastal Kalpakkam region in southern India during the Round Robin Exercise (RRE) field experiment period (14 -24 September 2010). Three nested domain with high resolution (18,6,2 km resolution) with 45 vertical levels are used. Four planetary boundary layer physics schemes [Yonsei University Scheme(YSU), Mellor-Yamada-Nakashini (MYN), Mellor-Yamada-Janjc and Asymmetric Convective Model (ACM2)] were tested. Model evaluations with available data indicated better simulation results with the Yonsei University scheme (YSU) PBL scheme. Simulations for the 10days period in 14-25 Sep'10 indicate that the model reproduces the trends in surface temperature, humidity, and winds with a reasonable good comparison with observations at most places. Overall, the model produced slightly warmer temperatures (MAE=1.2 C), slightly stronger winds (MAE= 1.75 ms-1) and with overestimation of winds by 15%. These simulations are reasonably good for air pollution dispersion application.