Simulation of the diurnal cycle of rainfall during Indian summer monsoon season using mesoscale model

Autor: Amit P. Kesarkar, Jyoti Bhate, V. P. M. Rajasree
Rok vydání: 2019
Předmět:
Zdroj: Theoretical and Applied Climatology. 138:185-200
ISSN: 1434-4483
0177-798X
Popis: Monsoon rainfall exhibits the prominent diurnal variability. It is essential to capture the diurnal behaviour of the rainfall on the spatiotemporal scale by mesoscale models for its accurate prediction. The present study appraises the diurnal variability of simulated rainfall by Weather Research and Forecasting (WRF) model over the South Asian region during Indian summer monsoon seasons of the years 2008–2012. For examining the amplitude, phase, and variance of the simulated diurnal cycle of rainfall, harmonic analysis of model outputs are carried out and compared it with that of TRMM rainfall estimates to quantify errors. The model is overall successful in simulating the pattern of diurnal variation of rainfall, but underestimates its amplitude compared to the observed one especially over the western Himalayas, northeast India, central India, and the north Bay of Bengal (BoB). However, the amplitudes of the diurnal variation match well over south BoB. The simulated phases of the diurnal cycle either leads (over central India and NW India by 3 h) or lags (over the sub-Himalayan region by 12 h) than the observed phase angle. The simulated time of maximum rainfall matches over south Peninsula, while over the west coast, neither observation nor forecast shows pronounced diurnal cycle. The north BoB shows morning maxima in rainfall in both observation and forecast; however, over south BoB, the time of maximum simulated rainfall leads by 3 h. Even though the model is overall successful in representing the diurnal variation of rainfall, it requires improvement for proper representation of phase and sub-diurnal variation appropriately.
Databáze: OpenAIRE
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