Sensitivity of Indian summer monsoon simulation to physical parameterization schemes in the WRF model

Abstract

A set of 17 experiments, using various combinations of physical parameterization schemes in the Weather Research and Forecasting (WRF) model, were carried out to choose a combination suitable for simulating the Indian summer monsoon. The model experiments, forced with the ERA-Interim reanalysis data, were at 30 km horizontal resolution. The WRF model experiments were initialized on 1 May of each year and integrated until 30 September to cover the entire monsoon season for the years 1982 to 2013. The results indicate that the simulated Indian summer monsoon precipitation and 2 m air temperature are sensitive to the physical parameterization schemes in the WRF model and that choosing the correct combination of physical parameterization schemes is essential for simulating the Indian summer monsoon realistically. Our analysis shows that a model setup with the Kain−Fritsch cumulus scheme, a radiation package with the Dudhia shortwave and Rapid Radiative Transfer Model longwave schemes, the Yonsei State University planetary boundary layer scheme, the WRF Single-Moment 3-class microphysics scheme, the revised MM5 Monin-Obukhov surface layer scheme, and the Unified Noah land surface model is suitable for simulating the precipitation realistically. The model setup with a combination of these physical parameterization schemes was found to have smaller biases and root mean square errors in the simulated precipitation, along with a realistic simulation of intraseasonal and interannual variability of precipitation. The results of this study will be useful to researchers and forecasters using the WRF model to improve the Indian summer monsoon simulations/ forecasts over the Indian region.

Quasi-asymmetric response of the Indian summer monsoon rainfall to opposite phases of the IOD

“…The role of different SST and other boundary conditions need further investigation using numerical models. But with known biases in coupled general circulation models 17 , perhaps sensitivity to different boundary conditions needs further studies with regional models 18 , 19 .

Figure 5 June-September composites of anomalous meridional circulation cells averaged between 65°E and 95°E ( a ) for pIOD and ( b ) for nIOD events.

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Impact of a Narrow Coastal Bay of Bengal Sea Surface Temperature Front on an Indian Summer Monsoon Simulation

“…The same set of model physics has been used by several studies for regional rainfall study. WRF is also widely used for ISM study 54 . We chose a single domain (Fig.…”

Evaluating Cumulus Parameterization Schemes for the Simulation of Arabian Peninsula Winter Rainfall

“…Several studies have investigated the sensitivity of rainfall simulations to CPSs in various regions. For instance, some studies highlighted the importance of choosing a suitable combination of parameterization schemes within the Weather Research and Forecasting (WRF) Model to simulate the rainfall features over the Indian region (Mukhopadhyay et al 2010;Srinivas et al 2013;Ratnam et al 2017). Similar efforts have been conducted for Australia (Evans et al 2012;Kala et al 2015), Spain (Argüeso et al 2011), Europe (Mooney et al 2013), China (Yuan et al 2012), South Africa (Crétat et al 2012;Ratna et al 2014), and the MENA region (e.g., Zittis et al 2014;Ehsan et al 2017).…”