scholarly journals Application of the NCAR Regional Climate Model to eastern Africa: 2. Simulation of interannual variability of short rains

1999 ◽  
Vol 104 (D6) ◽  
pp. 6549-6562 ◽  
Author(s):  
Liqiang Sun ◽  
Fredrick H. M. Semazzi ◽  
Filippo Giorgi ◽  
Laban Ogallo
Keyword(s):  
Regional Climate Model ◽  
Interannual Variability ◽  
Climate Model ◽  
Regional Climate ◽  
Eastern Africa ◽  
Short Rains

scholarly journals Application of the NCAR regional climate model to eastern Africa: 1. Simulation of the short rains of 1988

1999 ◽  
Vol 104 (D6) ◽  
pp. 6529-6548 ◽  
Author(s):  
Liqiang Sun ◽  
Fredrick H. M. Semazzi ◽  
Filippo Giorgi ◽  
Laban Ogallo
Keyword(s):  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Eastern Africa ◽  
Short Rains

scholarly journals Improving Climate Sensitivity of Deep Lakes within a Regional Climate Model and Its Impact on Simulated Climate

2014 ◽  
Vol 27 (8) ◽  
pp. 2886-2911 ◽  
Author(s):  
Val Bennington ◽  
Michael Notaro ◽  
Kathleen D. Holman
Keyword(s):  
Regional Climate Model ◽  
Interannual Variability ◽  
Climate Models ◽  
Climate Model ◽  
Regional Climate ◽  
Global Climate Models ◽  
Deep Lakes ◽  
Community Land Model ◽  
Lake Model ◽  
Lake Temperature

Abstract Regional climate models aim to improve local climate simulations by resolving topography, vegetation, and land use at a finer resolution than global climate models. Lakes, particularly large and deep lakes, are local features that significantly alter regional climate. The Hostetler lake model, a version of which is currently used in the Community Land Model, performs poorly in deep lakes when coupled to the regional climate of the International Centre for Theoretical Physics (ICTP) Regional Climate Model, version 4 (RegCM4). Within the default RegCM4 model, the lake fails to properly stratify, stifling the model’s ability to capture interannual variability in lake temperature and ice cover. Here, the authors improve modeled lake stratification and eddy diffusivity while correcting errors in the ice model. The resulting simulated lake shows improved stratification and interannual variability in lake ice and temperature. The lack of circulation and explicit mixing continues to stifle the model’s ability to simulate lake mixing events and variability in timing of stratification and destratification. The changes to modeled lake conditions alter seasonal means in sea level pressure, temperature, and low-level winds in the entire model domain, highlighting the importance of lake model selection and improvement for coupled simulations. Interestingly, changes to winter and spring snow cover and albedo impact spring warming. Unsurprisingly, regional climate variability is not significantly altered by an increase in lake temperature variability.

Customization of RegCM3 Regional Climate Model for Eastern Africa and a Tropical Indian Ocean Domain

2009 ◽  
Vol 22 (13) ◽  
pp. 3595-3616 ◽  
Author(s):  
Neil Davis ◽  
Jared Bowden ◽  
Fredrick Semazzi ◽  
Lian Xie ◽  
Bariş Önol
Keyword(s):  
Spatial Distribution ◽  
Indian Ocean ◽  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Eastern Africa ◽  
Massachusetts Institute Of Technology ◽  
Convective Rainfall ◽  
Total Rainfall ◽  
Sensitivity Tests

Abstract Rainfall is a driving factor of climate in the tropics and needs to be properly represented within a climate model. This study customizes the precipitation processes over the tropical regions of eastern Africa and the Indian Ocean using the International Centre for Theoretical Physics (ICTP) Regional Climate Model (RegCM3). The convective schemes of Grell with closures Arakawa–Schubert (Grell–AS)/Fritch–Chappel (Grell–FC) and Massachusetts Institute of Technology–Emanuel (MIT–EMAN) were compared to determine the most realistic spatial distribution of rainfall and partitioning of convective/stratiform rainfall when compared to observations from the Tropical Rainfall Measuring Mission (TRMM). Both Grell–AS and Grell–FC underpredicted convective rainfall rates over land, while over the ocean Grell–FC (Grell–AS) over- (under-) estimates convective rainfall. MIT–EMAN provides the most realistic pardoning and spatial distribution of convective rainfall despite the tendency for overestimating total rainfall. MIT–EMAN was used to further customize the subgrid explicit moisture scheme (SUBEX). Sensitivity tests were performed on the gridbox relative humidity threshold for cloudiness (RHmin) and the autoconversion scale factor (Cacs). An RHmin value of 60% (RHmin-60) reduced the amount of total rainfall over five heterogeneous rainfall regions in eastern Africa, with most of the reduction coming from the convective rainfall. Then, Cacs sensitivity tests improved upon the total rainfall amounts and convective stratiform partitioning compared to RHmin-60. Based upon all sensitivity simulations performed, the combination of the MIT–EMAN convective scheme, RHmin-60, and halving the model default value (0.4) of Cacs provided the most realistic simulation in terms of spatial distribution, convective partition, rainfall totals, and temperature bias when compared to observations.

scholarly journals Brief Communication: Upper air relaxation in RACMO2 significantly improves modelled interannual SMB variability in Antarctica

2015 ◽  
Vol 9 (5) ◽  
pp. 4981-4995
Author(s):  
W. J. van de Berg ◽  
B. Medley
Keyword(s):  
Regional Climate Model ◽  
Interannual Variability ◽  
Antarctic Peninsula ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Sheet ◽  
West Antarctica ◽  
Steep Topography ◽  
The Antarctic

Abstract. The regional climate model RACMO2 has been a powerful tool for improving SMB estimates from GCMs or reanalyses. However, new yearly SMB observations for West Antarctica show that the modelled interannual variability in SMB is poorly simulated by RACMO2, in contrast to ERA-Interim, which resolves this variability well. In an attempt to remedy RACMO2 performance, we included additional upper air relaxation (UAR) in RACMO2. With UAR, the correlation to observations is similar for RACMO2 and ERA-Interim. The spatial SMB patterns and ice sheet integrated SMB modelled using UAR remain very similar to the estimates of RACMO2 without UAR. We only observe an upstream smoothing of precipitation in regions with very steep topography like the Antarctic Peninsula. We conclude that UAR is a useful improvement for RCM simulations, although results in regions with steep topography should be treated with care.

scholarly journals Validation of the WRF regional climate model over the subregions of Southeast Asia: climatology and interannual variability

2017 ◽  
Vol 71 (3) ◽  
pp. 263-280 ◽  
Author(s):  
SB Ratna ◽  
JV Ratnam ◽  
SK Behera ◽  
FT Tangang ◽  
T Yamagata
Keyword(s):  
Southeast Asia ◽  
Regional Climate Model ◽  
Interannual Variability ◽  
Climate Model ◽  
Regional Climate
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