Ngo Duc Thanh, Trinh Tuan Long

Main Article Content

Abstract

This study presents, for the first time, the dynamical downscaled results at 25 km resolution for Vietnam from a global climate model participating in the Coupled Model Intercomparison Project Phase 6. The regional climate model (RegCM) version 4.7 was used with initial and boundary conditions from the global model CNRM-CM6-1 (referred to as CNRM) under the two Shared Socioeconomic Pathways (SSPs) 2-4.5 and 5-8.5. Simulated rainfall from RegCM and CNRM for the baseline period 1995–2014 is compared with the observation-based Vietnam Gridded Precipitation Dataset. The results indicate that downscaling is particularly effective in complex terrain areas, notably in the Central region during the winter monsoon season. However, in an overall assessment, the downscaled RegCM rainfall has not demonstrated added value compared to the CNRM results, whether in terms of annual variation, rainfall amounts, or spatial distribution. Future projection results until the end of the 21st century show an increase in average rainfall, rainfall intensity, and annual maximum daily rainfall in Vietnam under both SSP2-4.5 and SSP5-8.5 scenarios. The increase is projected to reach approximately 25% in the Northern coastal area in the RegCM experiment under SSP5-8.5. The increase in rainfall intensity is pronounced across most of Vietnam, particularly under SSP5-8.5. Regarding projected maximum daily rainfall, there are discrepancies between the regional climate model and the global model. While CNRM exhibits unclear trends in many areas, RegCM indicates an overall increase in maximum daily rainfall across most of Vietnam under both SSPs scenarios.


           

Keywords: Climate change, dynamical downscaling, rainfall, CMIP6, Vietnam.

References

[1] MONRE, Climate Change Scenarios, Vietnam Natural Resources, Environment and Mapping Publishing House, 2020, pp. 1-286 (in Vietnamese).
[2] MONRE, Climate Change and Sea Level Rise Scenarios for Vietnam, Vietnam Natural Resources, Environment and Mapping Publishing House, 2016, pp. 1-188 (in Vietnamese).
[3] MONRE, Climate Change and Sea Level Rise Scenarios for Vietnam, Ministry of Natural Resources and Environment, 2009, pp. 1-34
(in Vietnamese).
[4] MONRE, Climate Change and Sea Level Rise Scenarios for Vietnam, Vietnam Natural Resources, Environment and Mapping Publishing House, 2012, pp. 1-112 (in Vietnamese).
[5] N. D. Thanh, P. V. Tan, Non-parametric Test for Trend Detection of Some Meteorological Elements for the Period 1961-2007, VNU Journal of Science: Natural Sciences and Technology, Vol. 28, No. 3S, 2012, pp. 129-135 (in Vietnamese).
[6] H. P. Thanh, T. N. Duc, J. Matsumoto, T. P. Van, H. V. Van, Rainfall Trends in Vietnam and Their Associations with Tropical Cyclones During 1979-2019, Scientific Online Letters on the Atmosphere, Vol. 16, 2020, pp. 169-174, https://doi.org/10.2151/SOLA.2020-029.
[7] T. N. Duc, Rainfall extremes in Northern Vietnam: A Comprehensive Analysis of Patterns and Trends, Vietnam Journal of Earth Sciences, Vol. 45, No. 2, 2023, pp. 183-198, https://doi.org/10.15625/2615-9783/18284.
[8] T. N. Duc, Climate Change Scenarios for Southeast Asia and Vietnam: Current Status and Future Research Directions, VNU Journal of Science: Earth and Environmental Sciences, Vol. 39, No. 1, 2023, pp. 1-15, https://doi.org/10.25073/2588-1094/vnuees.4932.
[9] N. Nakicenovic, R. Swart, C. Cambridge University Press U. K., Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change, 2000, [Online] Available: http://www.grida.no/climate/ipcc/emission/index.htm (accessed on: September 1st, 2023).
[10] T. Ho, V. Phan, N. Le, Q. Nguyen, Extreme Climatic Events Over Vietnam from -Observational Data and Regcm3 Projections, Clim Res, Vol. 49, No. 2, 2011, pp. 87-100, https://doi.org/10.3354/cr01021.
[11] J. Katzfey et al., High-resolution Simulations for Vietnam - Methodology and Evaluation of Current Climate, Asia Pac J Atmos Sci, Vol. 52, No. 2, 2016, pp. 91-106, https://doi.org/10.1007/s13143-016-0011-2.
[12] T. N. Duc, C. Kieu, M. Thatcher, D. N. Le,
T. P. Van, Climate Projections for Vietnam Based on Regional Climate Models, Clim Res, Vol. 60, No. 3, 2014, pp. 199-213, https://doi.org/10.3354/cr01234.
[13] D. V. Vuuren et al., The Representative Concentration Pathways: An Overview, Clim Change, Vol. 109, No. 1-2, 2011, pp. 5-31, https://doi.org/10.1007/s10584-011-0148-z.
[14] L. T. Tuan, J. Matsumoto, T. N. Duc, M. I. Nodzu, T. Inoue, Evaluation of Satellite Precipitation Products Over Central Vietnam, Prog Earth Planet Sci, Vol. 6, No. 1, 2019, pp. 54, https://doi.org/10.1186/s40645-019-0297-7.
[15] Q. T. Anh, T. N. Duc, E. Espagne, L. T. Tuan, A High-Resolution Projected Climate Dataset for Vietnam: Construction and Preliminary Application in Assessing Future Change, Journal of Water and Climate Change, Vol. 13, No. 9, 2022, pp. 3379-3399, https://doi.org/10.2166/wcc.2022.144.
[16] L. Juneng et al., Sensitivity of Southeast Asia Rainfall Simulations to Cumulus and Air-Sea Flux Parameterizations in RegCM4, Clim Res, Vol. 69, No. 1, 2016, pp. 59-77, https://doi.org/10.3354/cr01386.
[17] F. T. Cruz et al., Sensitivity of Temperature to Physical Parameterization Schemes of Regcm4 Over the CORDEX-Southeast Asia Region, International Journal of Climatology, Vol. 37,
No. 15, 2017, pp. 5139-5153, https://doi.org/10.1002/joc.5151.
[18] T. N. Duc et al., Performance Evaluation of RegCM4 in Simulating Extreme Rainfall and Temperature Indices Over the CORDEX-Southeast Asia Region, International Journal of Climatology, Vol. 37, No. 3, 2017, pp. 1634-1647, https://doi.org/10.1002/joc.4803.
[19] F. Tangang et al., Projected Future Changes in Rainfall in Southeast Asia Based on CORDEX–SEA Multi-Model Simulations, Clim Dyn, Vol. 55, No. 5-6, 2020, pp. 1247-1267, https://doi.org/10.1007/s00382-020-05322-2.
[20] Supari et al., Multi-model Projections of Precipitation Extremes in Southeast Asia based on CORDEX-Southeast Asia simulations, Environ Res, Vol. 184, 2020, pp. 109350, https://doi.org/10.1016/j.envres.2020.109350.
[21] S. T. Ngai et al., Projected Mean and Extreme Precipitation Based on Bias-Corrected Simulation Outputs of CORDEX Southeast Asia, Weather Clim Extrem, Vol. 37, 2022, pp. 100484, https://doi.org/10.1016/j.wace.2022.100484.
[22] H. H. Cong et al., A High-resolution Climate Experiment Over Part of Vietnam and the Lower Mekong Basin: Performance Evaluation and Projection for Rainfall, Vietnam Journal of Earth Sciences, Vol. 44, No. 1, 2022, pp. 92-108, https://doi.org/10.15625/2615-9783/16942.
[23] V. Eyring et al., Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) Experimental Design And Organization, Geosci Model Dev, Vol. 9, No. 5, 2016, pp. 1937-1958, https://doi.org/10.5194/gmd-9-1937-2016.
[24] B. C. O’. Neill et al., The Roads Ahead: Narratives for Shared Socioeconomic Pathways Describing World Futures in the 21st Century, Global Environmental Change, Vol. 42, 2017, pp. 169-180, https://doi.org/ 10.1016/j.gloenvcha.2015.01.004.
[25] A. Voldoire et al., Evaluation of CMIP6 DECK Experiments with CNRM‐CM6‐1, J Adv Model Earth Syst, Vol. 11, No. 7, 2019, pp. 2177-2213, https://doi.org/10.1029/2019MS001683.
[26] T. N. Duy, T. N. Duc, Q. Desmet, Performance Evaluation and Ranking of CMIP6 Global Climate Models Over Vietnam, Journal of Water and Climate Change, Vol. 14, No. 6, 2023,
pp. 1831-1846, https://doi.org/10.2166/wcc.2023.454.
[27] F. Giorgi et al., RegCM4: Model Description and Preliminary Tests Over Multiple CORDEX Domains, Clim Res, Vol. 52, 2012, pp. 7-29, https://doi.org/10.3354/cr01018.
[28] N. D. Ngu, N. T. Hieu, Climate and Climate Resources of Vietnam, Agriculture Publishing House, 2004, pp. 1-230 (in Vietnamese).
[29] J. S. Kain, The Kain-Fritsch Convective Parameterization: An Update, J. Appl. Meteor. Climatol., Vol. 43, 2004, pp. 170-181, https://doi.org/10.1175/1520-0450(2004)043 <0170:TKCPAU>2.0.CO;2.
[30] C. S. Bretherton, J. R. McCaa, H. Grenier, A New Parameterization for Shallow Cumulus Convection and Its Application to Marine Subtropical Cloud-Topped Boundary Layers. Part I: Description and 1D Results, Mon Weather Rev, Vol. 132, No. 4, 2004, pp. 864-882, https://doi.org/10.1175/1520-0493(2004)132<0864:ANPFSC>2.0.CO;2.
[31] J. S. Pal et al., Regional Climate Modeling for the Developing World: The ICTP RegCM3 and RegCNET, Bull Am Meteorol Soc, Vol. 88, 2007, pp. 1395-1409,
https://doi.org/10.1175/BAMS-88-9-1395.
[32] X. Zeng, M. Zhao, R. E. Dickinson, Intercomparison of Bulk Aerodynamic Algorithms for the Computation of Sea Surface Fluxes Using TOGA COARE and TAO Data, J Clim, Vol. 11, No. 10, 1998, pp. 2628-2644,
https://doi.org/ 10.1175/1520-0442(1998)011 <26 2 8 :IOBAAF>2.0.CO;2.
[33] K. W. Oleson et al., Technical Description of Version 4.5 of the Community Land Model (CLM), NCAR Earth System Laboratory–Climate and Global Dynamics Division, Boulder, Colorado, 2013, pp. 1-434.
[34] T. N. Xuan et al., The Vietnam Gridded Precipitation (VnGP) Dataset: Construction and Validation, Scientific Online Letters on the Atmosphere, Vol. 12, 2016, pp. 291-296, https://doi.org/10.2151/sola.2016-057.
[35] Q. T. Anh, T. N. Duc, E. Espagne, L. T. Tuan, A 10-km CMIP6 Downscaled Dataset of Temperature and Precipitation for Historical and Future Vietnam Climate, Scientific Data, Vol. 10, 2023, pp. 257,
https://doi.org/10.1038/s41597-023-02159-2.
[36] C. J. Willmott, C. M. Rowe, W. D. Philpot, Small-Scale Climate Maps: A Sensitivity Analysis of Some Common Assumptions Associated with Grid-Point Interpolation and Contouring, the American Cartographer, Vol. 12, No. 1, 1985,
pp. 5-16, https://doi.org/10.1559/152304085783914686.
[37] U. Schneider, A. Becker, P. Finger, A. M. Christoffer, M. Ziese, B. Rudolf, GPCC’s New Land Surface Precipitation Climatology Based on Quality-Controlled in Situ Data and Its Role in Quantifying the Global Water Cycle, Theor Appl Climatol, Vol. 115, No. 1, 2013, pp. 15-40, https://doi.org/10.1007/s00704-013-0860-x.
[38] A. Yatagai, K. Kamiguchi, O. Arakawa,
A. Hamada, N. Yasutomi, A. Kitoh, APHRODITE: Constructing a Long-Term Daily Gridded Precipitation Dataset for Asia Based on a Dense Network of Rain Gauges, Bull Am Meteorol Soc, Vol. 93, No. 9, 2012, pp. 1401-1415, https://doi.org/10.1175/BAMS-D-11-00122.1.
[39] I. Harris, P. D. Jones, T. J. Osborn, D. H. Lister, Updated High-resolution Grids of Monthly Climatic Observations - the CRU TS3.10 Dataset, International Journal of Climatology, Vol. 34,
No. 3, 2014, pp. 623-642, https://doi.org/10.1002/joc.3711.
[40] H. Hersbach et al., The ERA5 Global Reanalysis, Quarterly Journal of the Royal Meteorological Society, Vol. 146, No. 730, 2020, pp. 1999-2049, https://doi.org/10.1002/qj.3803.
[41] K. E. Taylor, Summarizing Multiple Aspects of Model Performance in A Single Diagram, Journal of Geophysical Research: Atmospheres, Vol. 106, No. D7, 2001, pp. 7183-7192, https://doi.org/10.1029/2000JD900719.
[42] A. D. Luca, R. D. Elía, R. Laprise, Potential for Small Scale Added Value of RCM’s Downscaled Climate Change Signal, Clim Dyn, Vol. 40,
No. 3-4, 2013, pp. 601-618, https://doi.org/10.1007/s00382-012-1415-z.
[43] H. N. Thuy et al., Time of Emergence of Climate Signals Over Vietnam Detected from the CORDEX‐SEA Experiments, International Journal of Climatology, Vol. 41, No. 3, 2021,
pp. 1599-1618, https://doi.org/10.1002/joc.6897.
[44] L. T. Tuan et al., Application of Quantile Mapping Bias Correction for Mid-Future Precipitation Projections over Vietnam, Scientific Online Letters on the Atmosphere, Vol. 15, 2019, pp. 1-6, https://doi.org/10.2151/SOLA.2019-001.