Impact of Different Cumulus Parameterization Schemes in SAUDI-KAU AGCM

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Muhammad Azhar Ehsan ◽  
Mansour Almazroui ◽  
Ahmed Yousef
Keyword(s):  
Cumulus Parameterization ◽  
Parameterization Schemes ◽  
Cumulus Parameterization Schemes

scholarly journals Assessment of a Regional-Scale Weather Model for Hydrological Applications in South Korea

2016 ◽  
Vol 6 (2) ◽  
pp. 28
Author(s):  
Yong Jung ◽  
Yuh-Lang Lin
Keyword(s):  
Weather Prediction ◽  
Regional Scale ◽  
Wrf Model ◽  
Domain Size ◽  
Cumulus Parameterization ◽  
Precipitation Forecast ◽  
Mountainous Region ◽  
Parameterization Schemes ◽  
Plain Region ◽  
Cumulus Parameterization Schemes

<p class="1Body">In this study, a regional numerical weather prediction (NWP) model known as the Weather Research Forescasting (WRF) model was adopted to improve the quantitative precipitation forecasts (QPF) by optimizing combined microphysics and cumulus parameterization schemes. Four locations in two regions (plain region for Sangkeug and Imsil; mountainous region for Dongchun and Bunchun) in Korean Peninsula were examined for QPF for two heavy rainfall events 2006 and 2008. The maximum Index of Agreement (IOA) was 0.96 at Bunchun in 2006 using the combined Thompson microphysics and the Grell cumulus parameterization schemes. Sensitivity of QPF on domain size at Sangkeug indicated that the localized smaller domain had 55% (from 0.35 to 0.90) improved precipitation accuracy based on IOA of 2008. For the July 2006 Sangkeug event, the sensitivity to cumulus parameterization schemes for precipitation prediction cannot be ignored with finer resolutions. In mountainous region, the combined Thompson microphysics and Grell cumulus parameterization schemes make a better quantitative precipitation forecast, while in plain region, the combined Thompson microphysics and Kain-Frisch cumulus parameterization schemes are the best.</p>

scholarly journals Assessing the Accuracy of the Cloud and Water Vapor Fields in the Hurricane WRF (HWRF) Model Using Satellite Infrared Brightness Temperatures

2017 ◽  
Vol 145 (5) ◽  
pp. 2027-2046 ◽  
Author(s):  
Jason A. Otkin ◽  
William E. Lewis ◽  
Allen J. Lenzen ◽  
Brian D. McNoldy ◽  
Sharanya J. Majumdar
Keyword(s):  
Forecast Accuracy ◽  
Cloud Microphysics ◽  
Cumulus Parameterization ◽  
Upper Troposphere ◽  
Wind Speeds ◽  
Parameterization Schemes ◽  
Brightness Temperatures ◽  
Cumulus Parameterization Schemes ◽  
Hwrf Model ◽  
Infrared Brightness

Abstract In this study, cycled forecast experiments were performed to assess the ability of different cloud microphysics and cumulus parameterization schemes in the Hurricane Weather Research and Forecasting (HWRF) Model to accurately simulate the evolution of the cloud and moisture fields during the entire life cycle of Hurricane Edouard (2014). The forecast accuracy for each model configuration was evaluated through comparison of observed and simulated Geostationary Operational Environmental Satellite-13 (GOES-13) infrared brightness temperatures and satellite-derived tropical cyclone intensity estimates computed using the advanced Dvorak technique (ADT). Overall, the analysis revealed a large moist bias in the mid- and upper troposphere during the entire forecast period that was at least partially due to a moist bias in the initialization datasets but was also affected by the microphysics and cumulus parameterization schemes. Large differences occurred in the azimuthal brightness temperature distributions, with two of the microphysics schemes producing hurricane eyes that were much larger and clearer than observed, especially for later forecast hours. Comparisons to the forecast 10-m wind speeds showed reasonable agreement (correlations between 0.58 and 0.74) between the surface-based intensities and the ADT intensity estimates inferred via cloud patterns in the upper troposphere. It was also found that model configurations that had the smallest differences between the ADT and surface-based intensities had the most accurate track and intensity forecasts. Last, the cloud microphysics schemes had the largest impact on the forecast accuracy.

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

2012 ◽  
Vol 30 (5) ◽  
pp. 775-795 ◽  
Author(s):  
M. S. Deshpande ◽  
S. Pattnaik ◽  
P. S. Salvekar
Keyword(s):  
Inner Core ◽  
Intensity Variation ◽  
Cloud Microphysics ◽  
Cumulus Parameterization ◽  
Rapid Intensification ◽  
Parameterization Schemes ◽  
Sensitivity Experiments ◽  
Super Cyclone ◽  
Cumulus Parameterization Schemes ◽  
The Impact

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.

scholarly journals Why Are Tropical Cyclone Tracks over the Western North Pacific Sensitive to the Cumulus Parameterization Scheme in Regional Climate Modeling? A Case Study for Megi (2010)

2014 ◽  
Vol 142 (3) ◽  
pp. 1240-1249 ◽  
Author(s):  
Yuan Sun ◽  
Zhong Zhong ◽  
Wei Lu ◽  
Yijia Hu
Keyword(s):  
Tropical Cyclone ◽  
Climate Modeling ◽  
Deep Convection ◽  
Regional Climate ◽  
Lower Troposphere ◽  
Western Pacific Subtropical High ◽  
Regional Climate Modeling ◽  
Cumulus Parameterization ◽  
Parameterization Schemes ◽  
Cumulus Parameterization Schemes

Abstract The Weather Research and Forecasting Model is employed to simulate Tropical Cyclone (TC) Megi (2010) using the Grell–Devenyi (GD) and Betts–Miller–Janjić (BMJ) cumulus parameterization schemes, respectively. The TC track can be well reproduced with the GD scheme, whereas it turns earlier than observations with the BMJ scheme. The physical mechanism behind different performances of the two cumulus parameterization schemes in the TC simulation is revealed. The failure in the simulation of the TC track with the BMJ scheme is attributed to the overestimation of anvil clouds, which extend far away from the TC center and reach the area of the western Pacific subtropical high (WPSH). Such extensive anvil clouds, which result from the excessively deep convection in the eyewall, eventually lead to a large bias in microphysics latent heating. The warming of the upper troposphere due to the condensation in anvil clouds coupled with the cooling of the lower troposphere due to precipitation evaporation cause a weakening of the WPSH, which in turn is favorable for the early recurvature of Megi.

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