Performance evaluation of RegCM5 in long-term convection-permitting simulations for high-urbanized areas in Vietnam

Thanh Nguyen-Xuan; Dzung Nguyen-Le; Thanh Ngo-Duc

doi:10.15625/2615-9783/23431

Author affiliations

Authors

Thanh Nguyen-Xuan Department of Space and Earth Sciences, University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
Dzung Nguyen-Le Department of Space and Earth Sciences, University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
Thanh Ngo-Duc Department of Space and Earth Sciences, University of Science and Technology of Hanoi (USTH), Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam

DOI:

https://doi.org/10.15625/2615-9783/23431

Keywords:

Convection Permitting, RegCM5, Urban modeling

Abstract

This study is the first in Vietnam to assess the impact of urbanization on the local climate in Hanoi and Ho Chi Minh City using the Regional Climate Model version 5 (RegCM5) at convection-permitting (CP) resolution. Simulations were conducted at a horizontal grid spacing of 2 km, driven by the fifth-generation global reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ERA5), and incorporating annually updated urban information from 2000 to 2020. Unlike previous studies that relied on coarse-resolution simulations and static urban data, the latest version of RegCM5 enables stable long-term simulations with significantly reduced computational demands. The results yield three key findings. First, the 2 km simulations outperform those at 10 km resolution, highlighting the advantages of CP-scale modeling. In specific cases, the 2 km simulations even surpass the performance of the Vietnam Gridded Climate (VnGC) dataset when validated against station observations. Second, incorporating updated urban information allows the model to more accurately capture the temporal evolution of urbanization impacts, particularly evident from late afternoon (around 16:00 local solar time, LST) to midnight (around 01:00 LST). Third, the study finds that the urban heat island (UHI) effect in both cities is stronger during this late afternoon to midnight period and intensifies with increasing background temperatures. The UHI magnitude in Hanoi is generally greater than in Ho Chi Minh City.

Downloads

Download data is not yet available.

References

Coppola E., Stocchi P., Pichelli E., Torres Alavez J.A., Glazer R., Giuliani G., Di Sante F., Nogherotto R., Giorgi F., 2021. Non-Hydrostatic RegCM4 (RegCM4-NH): model description and case studies over multiple domains. Geosci. Model Dev., 14, 7705–7723. https://doi.org/10.5194/gmd-14-7705-2021.

Davolio S., Malguzzi P., Drofa O., Mastrangelo D., Buzzi A., 2020. The Piedmont flood of November 1994: a testbed of forecasting capabilities of the CNR-ISAC meteorological model suite. Bull. of Atmos. Sci. & Technol., 1, 263–282. https://doi.org/10.1007/s42865-020-00015-4.

Emanuel K.A., 1991. A Scheme for Representing Cumulus Convection in Large-Scale Models. J. Atmos. Sci., 48, 2313–2329. https://doi.org/10.1175/1520-0469(1991)048<2313:ASFRCC>2.0.CO;2.

Gao J., O'Neill B.C., 2020. Mapping global urban land for the 21st century with data-driven simulations and Shared Socioeconomic Pathways. Nat Commun, 11, 2302. https://doi.org/10.1038/s41467-020-15788-7.

Giorgi, F., 1990. Simulation of Regional Climate Using a Limited Area Model Nested in a General Circulation Model. J. Climate, 3, 941–963. https://doi.org/10.1175/1520-0442(1990)003<0941:SORCUA>2.0.CO;2.

Giorgi F., 2019. Thirty Years of Regional Climate Modeling: Where Are We and Where Are We Going next? JGR Atmospheres, 124, 5696–5723. https://doi.org/10.1029/2018JD030094.

Giorgi F., Coppola E., Giuliani G., Ciarlo’ J.M., Pichelli E., Nogherotto R., Raffaele F., Malguzzi P., Davolio S., Stocchi P., Drofa O., 2023. The Fifth Generation Regional Climate Modeling System, RegCM5: Description and Illustrative Examples at Parameterized Convection and Convection‐Permitting Resolutions. JGR Atmospheres 128, e2022JD038199. https://doi.org/10.1029/2022JD038199.

Grimmond C.S.B., et al., 2009. Urban surface energy balance models: model characteristics and methodology for a comparison study. In: Baklanov, A., et al. (Eds.), Meteorological and Air Quality Models for Urban Areas. https://doi.org/10.1007/978-3-642-00298-4_11.

Hersbach H., Bell B., Berrisford P., Hirahara S., Horányi A., Muñoz‐Sabater J., Nicolas J., Peubey C., Radu R., Schepers D., Simmons A., Soci C., Abdalla S., Abellan X., Balsamo G., Bechtold P., Biavati G., Bidlot J., Bonavita M., De Chiara G., Dahlgren P., Dee D., Diamantakis M., Dragani R., Flemming J., Forbes R., Fuentes M., Geer A., Haimberger L., Healy S., Hogan R.J., Hólm E., Janisková M., Keeley S., Laloyaux P., Lopez P., Lupu C., Radnoti G., De Rosnay P., Rozum I., Vamborg F., Villaume S., Thépaut J., 2020. The ERA5 global reanalysis. Quart J Royal Meteoro Soc., 146, 1999–2049. https://doi.org/10.1002/qj.3803.

Hoang-Cong H., Ngo-Duc T., Nguyen-Thi T., Trinh-Tuan L., Jing Xiang C., Tangang F., Jerasorn S., Phan-Van T., 2022. 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, 44(1), 92–108. https://doi.org/10.15625/2615-9783/16942.

Holtslag A.A.M., De Bruijn E.I.F., Pan H.-L., 1990. A High Resolution Air Mass Transformation Model for Short-Range Weather Forecasting. Mon. Wea. Rev., 118, 1561–1575. https://doi.org/10.1175/1520-0493(1990)118<1561:AHRAMT>2.0.CO;2.

Jackson T.L., Feddema J.J., Oleson K.W., Bonan G.B., Bauer J.T., 2010. Parameterization of Urban Characteristics for Global Climate Modeling. Annals of the Association of American Geographers, 100, 848–865. https://doi.org/10.1080/00045608.2010.497328.

Kiehl J., Hack J., Bonan G., Boville B., Williamson D., Rasch P., 1998. The national center for atmospheric research community climate model: CCM3. J. Climate, 11, 1131–1149.

Lowry W.P., 1977. Empirical Estimation of Urban Effects on Climate: A Problem Analysis. J. Appl. Meteor., 16, 129–135. https://doi.org/10.1175/1520-0450(1977)016<0129:EEOUEO>2.0.CO;2.

Martin-Vide J., Sarricolea P., Moreno-GarcÃa M.C., 2015. On the definition of urban heat island intensity: the "rural" reference. Front. Earth Sci., 3. https://doi.org/10.3389/feart.2015.00024.

Ngo-Duc T., Nguyen-Duy T., Desmet Q., Trinh-Tuan L., Ramu L., Cruz F., Dado J.M., Chung J.X., Phan-Van T., Pham-Thanh H., Truong-Ba K., Tangang F.T., Juneng L., Santisirisomboon J., Srisawadwong R., Permana D., Linarka U.A., Gunawan D., 2024. Performance Ranking of Multiple CORDEX-SEA Sensitivity Experiments: Towards an Optimum Choice of Physical Schemes for RegCM over Southeast Asia. Climate Dynamics, 62, 8659–8673. https://doi.org/10.1007/s00382-024-07353-5.

Nguyen-Le D., Trinh-Tuan L., Nguyen-Xuan T., Nguyen-Duy T., Ngo-Duc T., 2025. Projections of Heat Stress in Vietnam Using Physically-Based Wet-Bulb Globe Temperature. AFD Research papers, 346, 50. https://www.afd.fr/en/ressources/projections-heat-stress-vietnam-using-physically-based-wet-bulb-globe-temperature.

Nguyen-Ngoc-Bich P., et al., 2022. Projected future changes in drought characteristics over Southeast Asia. Vietnam Journal of Earth Sciences, 44(1), 127–143. https://doi.org/10.15625/2615-9783/16974.

Nguyen-Thi T., Ngo-Duc T., Phan-Van T., 2019. Performance of SEACLID/CORDEX-SEA multi-model experiments in simulating temperature and rainfall in Vietnam. Vietnam Journal of Earth Sciences, 41(4), 374–387. https://doi.org/10.15625/0866-7187/41/4/14259.

Nguyen-Xuan T., Im E.-S., 2023. Assessing the performance of the non-hydrostatic RegCM4 with the improved urban parameterization over southeastern China. Urban Climate, 49, 101527. https://doi.org/10.1016/j.uclim.2023.101527.

Nguyen-Xuan T., Zhou Z., Nguyen-Duy T., Nguyen-Le D., Ngo-Duc T., 2025. Optimizing Configurations for the Regional Climate Model (RegCM5) Using a Micro-GA Approach: A Case Study over Vietnam. Scientific Online Letters on the Atmosphere (SOLA), 21, 391–395. https://doi.org/10.2151/sola.2025-053.

Nogherotto R., Tompkins A.M., Giuliani G., Coppola E., Giorgi F., 2016. Numerical framework and performance of the new multiple-phase

cloud microphysics scheme in RegCM4.5: precipitation, cloud microphysics, and cloud radiative effects. Geosci. Model Dev., 9, 2533–2547. https://doi.org/10.5194/gmd-9-2533-2016.

Oleson K.W., Feddema J., 2020. Parameterization and Surface Data Improvements and New Capabilities for the Community Land Model Urban (CLMU). J Adv Model Earth Syst, 12, e2018MS001586. https://doi.org/10.1029/2018MS001586.

Oleson K.W., Lawrence D.M., 2013. Technical description of version 4.5 of the community land model (CLM). NCAR Technical Note NCAR/TN-503+STR, NCAR, Boulder, CO, USA. Open Topography, 2013. Shuttle Radar Topography Mission (SRTM) Global. https://doi.org/10.5069/G9445JDF.

Pal J.S., Giorgi F., Bi X., Elguindi N., Solmon F., Gao X., Rauscher S.A., Francisco R., Zakey A., Winter J., Ashfaq M., Syed F.S., Bell J.L., Diffenbaugh N.S., Karmacharya J., Konaré A., Martinez D., Da Rocha R.P., Sloan L.C., Steiner A.L., 2007. Regional Climate Modeling for the Developing World: The ICTP RegCM3 and RegCNET. Bulletin of the American Meteorological Society, 88, 1395–1410. https://doi.org/10.1175/BAMS-88-9-1395.

Pal J.S., Small E.E., Eltahir E.A.B., 2000. Simulation of regional‐scale water and energy budgets: Representation of subgrid cloud and precipitation processes within RegCM. J. Geophys. Res., 105, 29579–29594. https://doi.org/10.1029/2000JD900415.

Qian Y., Chakraborty T.C., Li J., Li D., He C., Sarangi C., Chen F., Yang X., Leung L.R., 2022. Urbanization impact on regional climate and extreme weather: current understanding, uncertainties, and future research directions. Adv. Atmos. Sci., 39, 819–860. https://doi.org/10.1007/s00376-021-1371-9.

Shepard D., 1968. A two-dimensional interpolation function for irregularly-spaced data, in: Proceedings of the 1968 23rd ACM National Conference. ACM Press, 517–524. https://doi.org/10.1145/800186.810616.

Tiedtke M., 1989. A Comprehensive Mass Flux Scheme for Cumulus Parameterization in Large-Scale Models. Mon. Wea. Rev., 117, 1779–1800. https://doi.org/10.1175/1520-0493(1989)117<1779:ACMFSF>2.0.CO;2.

Trinh-Tuan L., Ngo-Duc T., Phan-Van T., 2019. Vietnam Gridded Climate Dataset Version 2: Preliminary Results, In: Proceeding of the Carees 2019 workshop on Basic Research in the Field of Earth and Environmental Sciences. Publishing House for Science and Technology, Hanoi, Vietnam. https://doi.org/10.15625/vap.2019.000147.

Ünal Y.S., Sonuç C.Y., Incecik S., Topcu H.S., Diren-Üstün D.H., Temizöz H.P., 2020. Investigating urban heat island intensity in Istanbul. Theor Appl Climatol, 139, 175–190. https://doi.org/10.1007/s00704-019-02953-2.

United Nations, Department of Economic and Social Affairs, 2018. World Urbanization Prospects: The 2018. Revision, 123p. https://doi.org/10.18356/b9e995fe-en.

Yan Z.-W., Wang J., Xia J.-J., Feng J.-M., 2016. Review of recent studies of the climatic effects of urbanization in China. Advances in Climate Change Research, 7, 154–168. https://doi.org/10.1016/j.accre.2016.09.003.

Zeng X., Zhao M., Dickinson R.E., 1998. Intercomparison of bulk aerodynamic algorithms for the computation of sea surface fluxes using TOGA COARE and TAO data. J Clim, 11(10), 2628–2644. https://doi.org/10.1175/1520-0442(1998)011%3c2628:IOBAAF%3e2.0.CO;2.