Simulation of Rainfall over Bangladesh Using Regional Climate Model (RegCM4.7)

Authors

  • Muhammad Tanjilur Rahman University of Dhaka, Dhaka, Bangladesh
  • Md. Nazmul Ahasan University of Dhaka, Dhaka, Bangladesh
  • Md. Abdul Mannan Bangladesh Meteorological Department, Dhaka, Bangladesh
  • Madan Sigdel Tribhuvan University, Kathmandu, Nepal
  • Dibas Shrestha Tribhuvan University, Kathmandu, Nepal
  • Archana Shrestha Department of Hydrology and Meteorology, Kathmandu, Nepal
  • Deepak Aryal Tribhuvan University, Kathmandu, Nepal
  • Khan Md Golam Rabbani University of Dhaka, Dhaka, Bangladesh

DOI:

https://doi.org/10.3126/jalawaayu.v1i2.41007

Keywords:

RegCM4.7, Dynamic downscaling, Rainfall, Climate change, Bangladesh

Abstract

Regional climate model is a scientific tool to monitor present climate change and to provide reliable estimation of future climate projection. In this study, the Regional Climate Model version 4.7 (RegCM4.7) developed by International Centre for Theoretical Physics (ICTP) has been adopted to simulate rainfall scenario of Bangladesh. The study examines model performance of rainfall simulation through the period of 1991-2018 with ERA-Interim75 data of 75 km horizontal resolution as lateral boundaries, downscaled at 25km resolution using the mixed convective precipitation scheme; MIT-Emanuel scheme over land and Grell scheme with Fritsch-Chappell closure over ocean. The simulated rainfall has been compared both at spatial and temporal scales (monthly, seasonal and annual) with observed data collected from Bangladesh Meteorological Department (BMD) and Climate Research Unit (CRU). Simulated annual rainfall showed that the model overestimated in most of the years. Overestimation has been observed in the monsoon and underestimation in pre-monsoon and post-monsoon seasons. Spatial distribution of simulated rainfall depicts overestimation in the southeast coastal region and underestimation in the northwest and northeast border regions of Bangladesh. Better estimation of rainfall has been found in the central and eastern parts of the country. The simulated annual rainfall has been validated through the Linear Scaling bias correction method for the years of 2016, 2017, and 2018 considering the rainfall of 1991-2015 as reference. The bias correction with linear scaling method gives fairly satisfactory results and it can be considered in the future projection of rainfall over Bangladesh.

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Author Biographies

Muhammad Tanjilur Rahman, University of Dhaka, Dhaka, Bangladesh

Department of Meteorology

Md. Nazmul Ahasan, University of Dhaka, Dhaka, Bangladesh

Department of Meteorology

Madan Sigdel, Tribhuvan University, Kathmandu, Nepal

Central Department of Hydrology and Meteorology

Dibas Shrestha, Tribhuvan University, Kathmandu, Nepal

Central Department of Hydrology and Meteorology

Deepak Aryal, Tribhuvan University, Kathmandu, Nepal

Central Department of Hydrology and Meteorology

Khan Md Golam Rabbani, University of Dhaka, Dhaka, Bangladesh

Department of Meteorology

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Published

2021-12-02

How to Cite

Rahman, M. T., Ahasan, M. N., Mannan, M. A., Sigdel, M., Shrestha, D., Shrestha, A., Aryal, D., & Rabbani, K. M. G. (2021). Simulation of Rainfall over Bangladesh Using Regional Climate Model (RegCM4.7). Jalawaayu, 1(2), 1–19. https://doi.org/10.3126/jalawaayu.v1i2.41007

Issue

Section

Research Article