Study of Active and Break Spell Phenomena of Indian Summer Monsoon Using WRF Downscaled Data

This study evaluates the performance of a dynamically downscaled Weather Research and Forecasting (WRF) model by capturing characteristics interseasonal variability in terms active break spells Indian summer monsoon during period 1980–2014. We identify days based on standard criteria previous studies. Further, composite means rainfall different events, along with thermal dynamical features associated spells, are analyzed discussed. Our results clearly show that WRF reproduces observed circulation such as wider intensified lower tropospheric winds, presence mid-tropospheric cyclonic circulation, dominance strong upper-level tropical easterlies high influx moisture towards subcontinent. Even effectively simulates ERA, weaker winds at both low upper levels decreased strength northwesterly Shamal, inversion over northwestern part Arabian Sea, significant increase African easterly jet. Moreover, our analysis reveals accurately regional-scale precipitation. The also reveal spatial distributions moderate, heavy, very heavy events core region well captured model, only slight intensity variations compared to distributions.