Regional climate model application at subgrid scale on Indian winter monsoon over the western Himalayas

2012 ◽  
Vol 33 (9) ◽  
pp. 2185-2205 ◽  
Author(s):  
A. P. Dimri ◽  
D. Niyogi
2010 ◽  
Vol 23 (7) ◽  
pp. 1854-1873 ◽  
Author(s):  
E-S. Im ◽  
E. Coppola ◽  
F. Giorgi ◽  
X. Bi

Abstract A mosaic-type parameterization of subgrid-scale topography and land use (SubBATS) is applied for a high-resolution regional climate simulation over the Alpine region with a regional climate model (RegCM3). The model coarse-gridcell size in the control simulation is 15 km while the subgridcell size is 3 km. The parameterization requires disaggregation of atmospheric variables from the coarse grid to the subgrid and aggregation of surface fluxes from the subgrid to the coarse grid. Two 10-yr simulations (1983–92) are intercompared, one without (CONT) and one with (SUB) the subgrid scheme. The authors first validate the CONT simulation, showing that it produces good quality temperature and precipitation statistics, showing in particular a good performance compared to previous runs of this region. The subgrid scheme produces much finer detail of temperature and snow distribution following the topographic disaggregation. It also tends to form and melt snow more accurately in response to the heterogeneous characteristics of topography. In particular, validation against station observations shows that the SUB simulation improves the model simulation of the surface hydrologic cycle, in particular snow and runoff, especially at high-elevation sites. Finally, two experiments explore the model sensitivity to different subgrid disaggregation assumptions, namely, the temperature lapse rate and an empirical elevation-based disaggregation of precipitation.


2014 ◽  
Vol 8 (6) ◽  
pp. 6251-6270 ◽  
Author(s):  
A. P. Dimri

Abstract. Regional Climate Model(s) (RCMs) are sensitive towards presentation of regional climate of Indian winter monsoon (IWM) over the western Himalayas (WH). They illustrate robust nature in representing regional climate at mountain scale and even at event scale. While downscaling outputs, from these models, at basin level for hydrological and glaciological studies, it is found that RCMs fail to provide realistic figures. And hence, in the present paper, using the Siachen glacier basin as a reference, debate and deliberation on RCMs' uncertainly and high order of deviation from real observations is presented. Results from RCMs thus need "further tuning" if they are used for hydrological and glacier studies. Reasons for such uncertainties could be due to the improper representation of topography, missing subgrid scale processes, surface flux characteristics, various physical processes etc. at such finer model resolution and scale. At present, this paper only deliberates and brings out issues pertaining to such complexities to provide an insight for future course of studies, if understood correctly.


2014 ◽  
Vol 44 (9-10) ◽  
pp. 2839-2857 ◽  
Author(s):  
Stefan Lange ◽  
Burkhardt Rockel ◽  
Jan Volkholz ◽  
Bodo Bookhagen

2013 ◽  
Vol 57 (3) ◽  
pp. 173-186 ◽  
Author(s):  
X Wang ◽  
M Yang ◽  
G Wan ◽  
X Chen ◽  
G Pang

2020 ◽  
Vol 80 (2) ◽  
pp. 147-163
Author(s):  
X Liu ◽  
Y Kang ◽  
Q Liu ◽  
Z Guo ◽  
Y Chen ◽  
...  

The regional climate model RegCM version 4.6, developed by the European Centre for Medium-Range Weather Forecasts Reanalysis, was used to simulate the radiation budget over China. Clouds and the Earth’s Radiant Energy System (CERES) satellite data were utilized to evaluate the simulation results based on 4 radiative components: net shortwave (NSW) radiation at the surface of the earth and top of the atmosphere (TOA) under all-sky and clear-sky conditions. The performance of the model for low-value areas of NSW was superior to that for high-value areas. NSW at the surface and TOA under all-sky conditions was significantly underestimated; the spatial distribution of the bias was negative in the north and positive in the south, bounded by 25°N for the annual and seasonal averaged difference maps. Compared with the all-sky condition, the simulation effect under clear-sky conditions was significantly better, which indicates that the cloud fraction is the key factor affecting the accuracy of the simulation. In particular, the bias of the TOA NSW under the clear-sky condition was <±10 W m-2 in the eastern areas. The performance of the model was better over the eastern monsoon region in winter and autumn for surface NSW under clear-sky conditions, which may be related to different levels of air pollution during each season. Among the 3 areas, the regional average biases overall were largest (negative) over the Qinghai-Tibet alpine region and smallest over the eastern monsoon region.


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