Simulation of Indian summer monsoon circulation and rainfall using RegCM3

Dash, S. K.; Shekhar, M. S.; Singh, Gyan Prakash

doi:10.1007/s00704-006-0204-1

Cited by 152 publications

(112 citation statements)

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“…Its current configuration reflects almost two decades of improvements made in earlier versions in the representations of precipitation physics, surface physics, atmospheric chemistry and aerosols, planetary boundary layer parameterizations, radiative transfer, and the Biosphere-Atmosphere Transfer Scheme (BATS) (Pal et al, 2007). RegCM3 is a compressible, primitive-equation, sigma-vertical-coordinate, gridpoint-limited-area model with hydrostatic balance (Giorgi et al, 1993b,c;Giorgi and Marinucci, 1996;Giorgi and Shields, 1999;Dash et al, 2006;Pal et al, 2007). It is an improved and enhanced version of the NCAR RegCM2 (Giorgi et al, 1993b,c), with a dynamical core based on the hydrostatic version of MM5.…”

Section: Model Descriptionmentioning

confidence: 99%

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Evaluation and adaptation of a regional climate model for the Horn of Africa: rainfall climatology and interannual variability

Segele

Leslie

Lamb

2008

Intl Journal of Climatology

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This study evaluates the ability of the Abdus Salam International Center for Theoretical Physics (ICTP) version 3 Regional Climate Model (RegCM3) to reproduce the observed rainfall amounts and distribution over the topographically varied region of the Horn of Africa. Simulations are performed for the widespread very dry 1984 and locally very wet 1996 years using all of the alternative convective schemes available in the ICTP RegCM3. Extensive comparisons of simulations for 1984 and 1996 reveal that the Emanuel scheme best captures the rainfall patterns and interannual variations for the two extreme years over the Horn of Africa. This scheme therefore is selected for specific adaptation for the region, despite its excessive rainfall estimation there and its demonstrated deficiencies over other regions of Africa not of interest in this study.To reduce rainfall overestimation by the Emanuel scheme, several sensitivity experiments are performed by varying the key parameters that control the rate of convective mass flux, the fraction of condensed water converted to precipitation, and the heating and moistening characteristics of the environment. Results show that the amount of condensed water that ultimately falls out as rain crucially affects simulated rainfall amounts. With an appropriate adjustment to this key parameter, the excessive rainfall amount produced by the Emanuel scheme is reduced substantially. Furthermore, evaluation of RegCM3 simulations for [1982][1983][1984][1985][1986][1987][1988][1989][1990][1991][1992][1993][1994][1995][1996][1997][1998][1999] shows that the modified Emanuel convective scheme not only reproduces the 18-year average rainfall realistically but also captures the interannual variability adequately over the Horn of Africa. The correlation between the modified Emanuel-simulated and Ethiopian station rainfall is quite strong (+0.66). This customized ICTP RegCM3 model now can be used with confidence for the Horn of Africa to study regional rainfall processes and variability and to dynamically downscale seasonal rainfall forecasts.

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Section: Model Descriptionmentioning

confidence: 99%

“…Owing to the simplistic nature of the Grell scheme, several closure assumptions can be used to relate the mass flux at the bottom of the updraft to the large-scale forcing (e.g. Dash et al, 2006). RegCM3 implements the quasiequilibrium closure assumption of Arakawa and Schubert (1974).…”

Section: Model Descriptionmentioning

confidence: 99%

Evaluation and adaptation of a regional climate model for the Horn of Africa: rainfall climatology and interannual variability

Segele

Leslie

Lamb

2008

Intl Journal of Climatology

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“…The RCMs by virtue of higher horizontal resolution are expected to better simulate the regional dynamics associated with intraseasonal oscillations on different time scales, break spells associated with variations in Intertropical Convergence Zone (ITCZ) and those associated with life cycles of monsoon depressions than the driving GCM (Bhaskaran et al, 1996). Secondly, the RCMs have the advantages of high resolution and improved physics (such as convection) to resolve the regional features associated with topography, local climate and the associated precipitation (Bhaskaran et al, 1996;Das et al, 2006). Several studies on ISM and its seasonal rainfall patterns have been reported using RCMs (Bhaskaran et al, 1996;Ji and Verneker, 1997;Bhaskar Rao et al, 2004;Fu et al, 2005;Das et al, 2006;Cui et al, 2007;Im et al, 2008;Ashfaq et al, 2009;Ratnam et al, 2009;Sato et al, 2009;Dobler and Ahrens, 2010;Polanski et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Secondly, the RCMs have the advantages of high resolution and improved physics (such as convection) to resolve the regional features associated with topography, local climate and the associated precipitation (Bhaskaran et al, 1996;Das et al, 2006). Several studies on ISM and its seasonal rainfall patterns have been reported using RCMs (Bhaskaran et al, 1996;Ji and Verneker, 1997;Bhaskar Rao et al, 2004;Fu et al, 2005;Das et al, 2006;Cui et al, 2007;Im et al, 2008;Ashfaq et al, 2009;Ratnam et al, 2009;Sato et al, 2009;Dobler and Ahrens, 2010;Polanski et al, 2010). These studies used regional models with resolutions of 50 km and less and reported successful simulation of the intraseasonal oscillations and considerable improvements of ISM rainfall over atmospheric GCMs.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the Indian summer monsoon regional climate using advanced research WRF model

Srinivas

Hariprasad

Rao

et al. 2012

Intl Journal of Climatology

117

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ABSTRACT:In this study, the performance of the weather research and forecasting (WRF) ARW regional model was evaluated for simulating the regional scale precipitation during Indian summer monsoon (ISM) at 30 km resolution over seven different homogeneous rainfall zones falling under different climatic (perhumid, humid, dry/moist subhumid, dry/moist semiarid, arid) regions of India. Seasonal scale simulations were made for ten summers (JJAS months) over 2000-2009 using the boundary conditions derived from the National Centers for Environmental Prediction (NCEP) reanalysis data. Sensitivity experiments were conducted with three convection schemes (Kain-Fritsch, KF; Betts-Millor-Janjic, BMJ; GrellDevenyi, GD). Simulated regional climate was evaluated by comparison of precipitation with 0.5°India Meteorological Department (IMD) gridded rainfall data over land, Tropical Rainfall Measuring Mission (TRMM) rainfall data over the ocean and atmospheric circulation fields with 1°NCEP global final analysis (FNL). Although all the simulations showed spatio-temporal rainfall patterns, BMJ had least bias towards dryness whereas KF had moist bias and GD had higher dry bias. BMJ could simulate low, moderate and high rainfall reasonably well with relatively higher correlations and threat scores, lower bias and mean absolute errors in most zones as compared to better simulation of heavy precipitation events with KF and low rainfall days alone with GD scheme. The better performance of BMJ scheme is evident owing to better simulation of surface pressure, temperature, and geopotential, lower and upper atmospheric flow fields. Simulations revealed a relatively less intensive heat, weaker low-level westerly winds, weaker north-south geopotential gradients, weaker subtropical easterlies in the El Niño years than in the La Niña years, which indicate the model is able to simulate the interannual variations in monsoon characteristics.

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“…The model used in the present study is again ICTP regional climate model (RCM) RegCM4.0 [12][13][14][15] installed over the Cordex South Asia domain (12°E to 138°E and 33°S to 55°N) at 90 km horizontal resolution [8,11]. The details of the parameterization schemes and domain of the regional climate model are described in the Lodh [10].…”

Section: Methodsmentioning

confidence: 99%

Simulated Impact of Desertification and Deforestation on Indian Monsoon Rainfall and Surface Fluxes: RegCM4.0 Simulations

Lodh¹

2017

J Ecosyst Ecogr

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Impact of extensive desertification in northwest India, Himalayan glaciers depletion and tropical deforestation over Indian subcontinent and Southeast Asia, on Indian monsoon circulations, precipitation, surface fluxes is being studied. In this research paper, by changing vegetation types in the bats coupled -regCM4.0, the model impact of desertification and deforestation on Indian monsoons is investigated. By performing these sensitivity experiments (extended desertification, and tropical deforestation) it is found that over India, monsoon precipitation is significantly decreased at local and large scales. Decreased surface roughness length and increase in albedo because of desertification/deforestation in the model results in origination of anomalous westerly winds and subsidence, decreasing turbulent flow, decreasing rainfall over land and strengthening over the seas and consequently increases the temperature over land. Further, the hydrological and atmospheric water cycle gets weak because precipitation decreases. Thus any form of deforestation and desertification happening over tropical regions has a severe impact on Indian summer monsoon atmospheric circulations and precipitation. Lodh [9,10], studies impact of impact of afforestation and irrigation intensification on Indian monsoon precipitation and circulations, respectively. In this present research work attempts are made to study increase in desertification and deforestation in the RegCM4.0 model by proxy land use and land cover change induced sensitivity experiments, and to arrive at conclusions in addition to previous studies. Thus, identification of possible changes on regional precipitation and circulation patterns in the Indian monsoon regime through the sensitivity experiments is planned, using a regional climate model. Also, the mechanisms of interaction between land surface and vegetation (via desertification and deforestation) are to be understood. In this paper, the methodology, brief about the sensitivity experiments and their period of study is described in Section 2. "Result and Discussions" of the sensitivity experiment about effect of extensive desertification and deforestation is described in Section 3, and the "Summary and Conclusions" are described in Section 4. MethodologyThe model used in the present study is again ICTP regional climate model (RCM) installed over the Cordex South Asia domain (12°E to 138°E and 33°S to 55°N) at 90 km horizontal resolution [8,11]. The details of the parameterization schemes and domain of the regional climate model are described in the Lodh [10]. Brief about the desertification and deforestation sensitivity experiments and their period of studyThe desertification and deforestation sensitivity experiments are performed to study the critical impact of anthropogenic human activities by conducting landuse and land cover changes in the model, on Indian summer monsoon precipitation and circulation pattern (Figure 1). They are: (a) In the first (DEFOR EXP 1) sensitivity experiment the model landuse p...

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Simulation of Indian summer monsoon circulation and rainfall using RegCM3

Cited by 152 publications

References 20 publications

Evaluation and adaptation of a regional climate model for the Horn of Africa: rainfall climatology and interannual variability

Evaluation and adaptation of a regional climate model for the Horn of Africa: rainfall climatology and interannual variability

Simulation of the Indian summer monsoon regional climate using advanced research WRF model

Simulated Impact of Desertification and Deforestation on Indian Monsoon Rainfall and Surface Fluxes: RegCM4.0 Simulations

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