Impact of cloud parameterization on the numerical simulation of a super cyclone

Abstract

Abstract. This study examines the role of parameterization of convection and explicit moisture processes on the simulated track, intensity and inner core structure of Orissa super cyclone (1999) in Bay of Bengal (north Indian Ocean). Sensitivity experiments are carried out to examine the impact of cumulus parameterization schemes (CPS) using MM5 model (Version 3.7) in a two-way nested domain (D1 and D2) configuration at horizontal resolutions (45-15 km). Three different cumulus parameterization schemes, namely Grell (Gr), Betts-Miller (BM) and updated Kain Fritsch (KF2), are tested. It is noted that track and intensity both are very sensitive to CPS and comparatively, KF2 predicts them reasonably well. Particularly, the rapid intensification phase of the super cyclone is best simulated by KF2 compared to other CPS. To examine the effect of the cumulus parameterization scheme at high resolution (5 km), the three-domain configuration (45-15-5 km resolution) is utilized. Based on initial results, KF2 scheme is used for both the domains (D1 and D2). Two experiments are conducted: one in which KF2 is used as CPS and another in which no CPS is used in the third domain. The intensity is well predicted when no CPS is used in the innermost domain. The sensitivity experiments are also carried out to examine the impact from microphysics parameterization schemes (MPS). Four cloud microphysics parameterization schemes, namely mixed phase (MP), Goddard microphysics with Graupel (GG), Reisner Graupel (RG) and Schultz (Sc), are tested in these experiments. It is noted that the tropical cyclone tracks and intensity variation have considerable sensitivity to the varying cloud microphysical parameterization schemes. The MPS of MP and Sc could very well capture the rapid intensification phase. The final intensity is well predicted by MP, which is overestimated by Sc. The MPS of GG and RG underestimates the intensity.

Impacts of Microphysics Schemes and Topography on the Prediction of the Heavy Rainfall in Western Myanmar Associated with Tropical Cyclone ROANU (2016)

“…Their results imply that the intensification rate and final intensity of a simulated tropical cyclone are sensitive to the detail of the cloud microphysics parameterization used in the numerical models. The cloud microphysical processes are a major portion of the latent heat release [11]. The energy at the ocean exchange and supply through the planetary boundary layer to the free atmosphere play an important role in the intensification of the TC [12].…”

A comparative evaluation of impact of domain size and parameterization scheme on simulation of tropical cyclones in the Bay of Bengal

“…Similarly, the tropical cyclones are primarily driven by convective heating, and thus, representation of convection plays a very important role in simulation of tropical cyclones. The importance of convection and thus convective parameterization scheme in mesoscale simulation is well known, and a large number of studies [Seth and Giorgi, 1998;Liang et al, 2001;Landman et al, 2005;Stensrud, 2007;Hogan and Pauley, 2007;Bao et al, 2012;Chandrasekar and Balaji, 2012;Deshpande et al, 2010Deshpande et al, , 2012 have examined this issue in the context of various mesoscale systems over different regions [Gomez et al, 2011]. While the importance of domain size for simulation of extreme rainfall events has been demonstrated [Goswami et al, 2012], it is not clear however if such sensitivity to size of the domain also holds for atmospheric systems of larger scales, such as tropical cyclones.…”

Understanding the Role of Cloud and Convective Processes in Simulating the Weaker Tropical Cyclones over Indian Seas

“…For the past few decades, the track and intensity forecasting of cyclones has significantly improved, particularly over the Atlantic and Pacific basins (FRANKLIN 2005;DEMARIA et al 2005), but the forecasting has not yet reached the desired level of accuracy over the Indian Ocean basin. Several simulation studies have been conducted to study the TCs over the NIO using highresolution mesoscale models (PATTANAYAK and MOH-ANTY 2008;DESHPANDE et al 2010DESHPANDE et al , 2012TRIVEDI et al 2006;OSURI et al 2012, OSURI et al 2013BHASKAR RAO et al 2009;SRINIVAS et al 2007SRINIVAS et al , 2010RAJU et al 2011). These studies are based on evaluating the model performance with respect to the physics sensitivity, resolution, initial conditions and impact of data assimilation on the track and intensity forecast of very severe cyclones.…”

“…These heating rates are dependent on the cloud microphysical process within the systems and thus on the latent heat released by the condensate. PATTNAIK and KRISHNAM- URTI (2007a, b) demonstrated that the latent heat produced during the conversion of hydrometeors produces more instability, an increased buoyancy gradient and higher tropical cyclone intensity (DESH-PANDE et al 2010, DESHPANDE et al 2012. Some studies also suggest that suppressing the microphysical processes such as inclusion of ice processes (LORD et al 1984), evaporation and melting (ZHU and ZHANG 2006) produces a rapid intensification and thus results in a stronger storm.…”

“…Therefore, even with a horizontal resolution of *10 km or less (GERARD 2007;DESHPANDE et al 2012), the mesoscale may be resolved but the deep convective clouds still need to be parameterized (MOLINARI 1993;FOVELL and SU 2007). To resolve the issue of grid-scale and subgridscale convection, MOLINARI (1993) emphasized the need for a hybrid approach in numerical models.…”