Effect of cloud microphysics on Indian summer monsoon precipitating clouds: A coupled climate modeling study

Abstract

The quest for one of the most dominant processes controlling the large‐scale circulations in the tropics is unraveled. The impact of cloud microphysical processes is known to have effects on rainfall and local atmospheric thermodynamics; however, its effect on the prevailing mean circulations is not yet studied. Two sets of coupled global climate model experiments (ICE and NO ICE microphysics) reveal that ice microphysics improves the strength of the Hadley circulation with respect to observation. Results pinpoint that ICE simulation enhances high cloud fraction (global tropics: ~59%, India: ~51%) and stratiform rain (global tropics: ~5%, India: ~15%) contribution. ICE and NO ICE cloud microphysics impacts differently on the outgoing longwave radiation (OLR), tropospheric temperature, and surface shortwave and longwave radiation. The effect of ice microphysics reduces OLR, which signifies deeper convection in the ICE run. The global annual average of the net radiation flux (shortwave and longwave) at the surface in ICE run (108.1 W/m2) is close to the observation (106 W/m2), which is overestimated in NO ICE run (112 W/m2). The result of apparent heat source term over the land and ocean surface eventually modifies regional Hadley circulation. Thus, the effect of ice microphysics in the global coupled model is important not only because of microphysics but also due to the radiation feedbacks. Therefore, better ice‐phase microphysics is required in the new generation of climate forecast model, which may lead to improvements in the simulation of monsoon.

A diagnostic study of cloud physics and lightning flash rates in a severe pre‐monsoon thunderstorm over northeast India

“…CWMR was confined to below 12 km with a peak value at 2 km. The water vapour and cloud liquid water are lifted up by strong updraughts, and cloud ice particles grow at the expense of water vapour and cloud liquid water at the higher altitudes through vapour deposition (Wegener–Bergeron–Findeisen process) and freezing (Korolev, ; Hazra et al ., ; ), respectively. The mixed‐phase hydrometeors such as snow and graupel formation take place by the auto‐conversion of cloud ice and through the collision between ice particles and cloud droplets (i.e.…”

Simulation of extreme Indian summer monsoon years in Coupled Model Intercomparison Project Phase 5 models: Role of cloud processes

“…Previous studies (Rajeevan et al ., ; Chaudhari et al ., ; ) have pointed out that proper representation of vertical structure of cloud hydrometeors is indispensable in climate model for realistic representation of ISM. Vertical structure is important for heating/cooling which further feedback to large‐scale circulation (Hazra et al ., ; ) and hence have impact on ISM. Pressure‐latitude cross‐section of mean cloud ice fraction (averaged over 40°–120°E) is shown for CMIP5 models along with ERA‐Interim and MERRA (Figure a–h: excess monsoon; Figure i–p: deficient monsoon).…”

“…Thus, it is challenging to unravel the characteristics and mechanism of monsoon variability. Recently, the development of coupled climate models has provided important advances in the monsoon understanding (Wang et al ., ; Saha et al ., ; Hazra et al ., ; ). Several studies have explored various aspects of monsoon using Coupled Model Intercomparison Project Phase 5 (CMIP5) models (e.g., Sperber et al ., ; Freychet et al ., ; Sabeerali et al ., ; Preethi et al ., ).…”

Contrast in monsoon precipitation over oceanic region of north Bay of Bengal and east equatorial Indian Ocean

“…Large number of previous studies have used both CSH and 3A12 for intra‐seasonal and seasonal studies (e.g. Chan and Nigam, ; Zuluaga et al ., ; Zhang et al ., ; Hazra et al ., ), with the caution of their use over land, due to lack of extensive evaluation. Our study domain only considers the latent heat estimates over the ocean and thus retains the caution to be applied for the use of the data.…”