Intercomparison of the impact of INSAT-3D atmospheric motion vectors in 3DVAR and hybrid ensemble-3DVAR data assimilation systems during Indian summer monsoon

The impact of observations in a data assimilation (DA) may depend on various factors, and one aspect that can affect the is specification background error covariance matrix. present study compares INSAT-3D atmospheric motion vector (AMV) traditional three-dimensional variational (3DVAR) DA system hybrid ensemble transform Kalman filter (ETKF)-3DVAR (HYBRID) available Weather Research Forecast (WRF) modeling system. objective to understand how AMV differ when assimilated using 3DVAR HYBRID systems. experiments are conducted over ~4-week period Indian summer monsoon rainfall July 2016. Four sets performed with without both domain-wide verification respect radiosonde reveals forecasts more accurate than experiments, general. Geographical distribution depicts positive impacts across domain show larger relative 3DVAR. improvement compared 77% 71% for wind tropical temperature. skill scores quantitative evaluation precipitation forecast indicate modest run, incorporating observation does not considerably enhance 24-h 48-h forecast.