Impact of horizontal resolution on monsoon precipitation for CORDEX-South Asia: A regional earth system model assessment

dmitry.sein [ at ]


For the first time for CORDEX-South Asia, a high-resolution regional earth system model (ROM) is adopted to assess the impact of horizontal resolution (0.22◦ and 0.11◦) in simulating the Indian summer monsoon rainfall (ISMR) and the underlying spatiotemporal variability. ROM at both resolutions bears a close resemblance to observations in simulating the mean precipitation climatology compared to other regional climate models (RCMs) participated in CORDEX- South Asia. ROM shows substantial improvement relative to the ensemble mean of the RCMs included in CORDEX-South Asia. While comparing both simulations with observations, some sys-tematic wet and dry bias over Central India (CI) and Northern Western Ghats is noticed. In general, the wet/dry bias over India is mainly associated with the overestimation/underestimation of the large-scale/convective component. Increasing horizontal resolution from 0.22◦ to 0.11◦ significantly adds value in simulating the JJAS mean precipitation by reducing the wet bias over western central India (WCI) and southern peninsular India and dry bias over eastern CI. The reduction in wet/dry bias is mainly associated with suppression/enhancement of the large scale/convective precipitation. This improvement in mean precipitation is partially due to the improved representation of the propagation of mesoscale systems such as boreal summer intraseasonal oscilla-tion (eastward and northward). Despite the above improvements, the wet precipitation bias, particularly over WCI, persists. The weaker Findlater Jet associated with weaker land-ocean thermal contrast caused by the warm sea surface temperature (SST) bias over the western Arabian Sea (AS) suggests that AS moisture transport does not contribute to the wet bias over India. The wet bias is possibly associated with favourable atmospheric conditions (atmospheric instability).

Item Type
Primary Division
Primary Topic
Publication Status
Eprint ID
DOI 10.1016/j.atmosres.2021.105681

Cite as
Mishra, A. K. , Kumar, P. , Dubey, A. K. , Javed, A. , Saharwardi, M. S. , Sein, D. V. , Martyanov, S. D. and Jacob, D. (2021): Impact of horizontal resolution on monsoon precipitation for CORDEX-South Asia: A regional earth system model assessment , Atmospheric Research, 259 . doi: 10.1016/j.atmosres.2021.105681

[thumbnail of s2_0_S0169809521002337_main.pdf]

Download (7MB) | Preview

Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Geographical region

Research Platforms


Edit Item Edit Item