Analysis of Statistical Downscaling Model (SDSM) projected future rainfall in Northwestern, Western and Southern provinces of Sri Lanka

Mohamed Riflan, Miyuru B. Gunathilake, Jayanga T. Samarasinghe, Isuru M. Bandara, Imiya M. Chathuranika, Upaka Rathnayake

Abstract


Even though an extensive amount of climate change studies have been carried out in different parts of the world, Sri Lanka is one of the least focused countries in this regard. Climate projections are important and encouraged to manage the futuristic adverse impacts. Identifying this research gap, future rainfall projections were carried out in three provinces in Sri Lanka, i.e. Northwestern (Puttalam and Kurunegala), Western (Katunayake and Colombo), and Southern province (Galle and Hambantota). The Canadian Earth System Model (CanESM2) under the Representation Concentration Pathways (RCP8.5) was downscaled using the Statistical DownScaling Model (SDSM). Non-parametric tests, including Mann-Kendall (MK) test and the Sen’s Slope estimator, were used to determine the significance of trends and magnitude of the slope of the historical trends (1990-2019) and future projected trends (2020-2100). The trends were analyzed for four major seasons in Sri Lanka, including First Inter-monsoon (FIM), Southwest monsoon (SWM), Second Inter-monsoon (SIM), and the Northeast monsoon (NEM). The standard error and model bias at rainfall stations were 0.014-0.034 mm and 1-1.1 respectively, which are acceptable when compared to previous studies. Several significant rainfall trends were identified, including positive trends in the mid-future (2041-2070), and negative trends in the far-future (2071-2100). In addition, rainfall indices, including Rx5day, R20mm, Consecutive dry days (CDD), and Consecutive wet days (CWD) were tested in future projected and historical rainfalls. The results of the present study will be useful for policymakers for decision-making processes in water resources management and agriculture.
Keywords: Non-parametric tests, projected rainfall, rainfall indices, rainfall trends, Statistical Down Scaling Model (SDSM).

Full Text:

PDF

References


Agarwal A. Babel MS, Maskey S. 2015. Estimating the Impacts and Uncertainty of Climate Change on the Hydrology and Water Resources of the Koshi River Basin. In: Shrestha S., Anal A., Salam P., van der Valk M. (eds) Managing Water Resources under Climate Uncertainty. Springer Water. Springer, Cham, pp. 105-126. https://doi.org/10.1007/978-3-319-10467-6-6

Alahacoon N, Edirisinghe M. 2021. Spatial variability of rainfall trends in Sri Lanka from 1989 to 2019 as an indication of climate change. ISPRS International Journal of Geo-Information 10(2-84): 1-18. doi: 10.3390/ijgi10020084

Amarasinghe AG. 2020. Analysis of long-term rainfall trends in Sri Lanka Using CHRIPS estimates. American Journal of Multidisciplinary Research & Development (AJMRD) 2(11): 34-44.

Bandara IM, Weerakoon SB. 2020. Trend analysis of historical and downscaled future climate data in Deduru-Oya basin, Sri Lanka. WASO Final Virtual Conference, Norway, 15-18 December 2020.

Basnayake BRSB, Vithanage JC. 2004. Rainfall change scenarios for Sri Lanka under the anticipated climate change. In: Proceedings of the International Conference on Sustainable Water Resources Management in the Changing Environment of the Monsoon Region. Colombo, Sri Lanka.

Basnayake BRSB, Rathnasiri J, Vithanage JC. 2004. Rainfall and temperature scenarios for Sri Lanka under the anticipated climate change. 2nd AIACC Regional Workshop for Asia and the Pacific, Manila, Philippines, 2-5 November 2004.

Bates BC, Kundzewicz ZW, Wu S, Palutikof JP. (eds.) 2008. Climate Change and Water: Technical Paper of the Intergovernmental Panel on Climate Change. Geneva: IPCC Secretariat. Pp 210.

Chandrapala L. 1996. Long term trends of rainfall and temperature in Sri Lanka. Climate Variability and Agriculture, Abrol YP, Gadgil S, Pant GB, Eds., Narosa Publishing House, New Delhi, 153-162.

Chen J, Brissette F, Chaumont D, Braun M. 2013. Finding appropriate bias correction methods in downscaling precipitation for hydrologic impact studies over North America. Water Resources Research 49(7): 4187-4205. doi: 10.1002/wrcr.20331.

Chylek P, Li J, Dubey M, Wang M, Lesins G. 2011. Observed and model simulated 20th century Arctic temperature variability: Canadian Earth System Model CanESM2. Atmospheric Chemistry and Physics 11(8): 22893-22907. doi: 10.5194/acpd-11-22893-2011.

Cui T, Yang T, Xu C, Shao Q, Wang X, Li Z. 2018. Assessment of the impact of climate change on flow regime at multiple temporal scales and potential ecological implications in an alpine river. Stochastic Environmental Research and Risk Assessment 32(6): 1849-1866. doi: 10.1007/s00477-017-1475-z

Dantanarayana M, Herath S, Weerakoon SB. 2021. Improving sub daily scale storm forecasting for Kelani River basin based on temporal distribution of rain events. Journal of Climatology & Weather Forecasting 9(1): 1-9.

Dashkhuu D, Kim JP Chun, JA, Lee WS. 2015. Long-term trends in daily temperature extremes over Mongolia. Weather and Climate Extremes 8: 26–33.

De Costa WAJM. 2008. Climate change in Sri Lanka: myth or reality? Evidence from long-term meteorological data. Journal of the National Science Foundation of Sri Lanka 36: 63–88. http://doi.org/10.4038/jnsfsr.v36i0.8048

De Costa WAJM. 2012. Climate change research in Sri Lanka – Are we investigating enough? Journal of the National Science Foundation of Sri Lanka, 40(4), 281–282.

http://doi.org/10.4038/jnsfsr.v40i4.5041

De Silva CS. 2006. Impacts of climate change on water resources in Sri Lanka. 32nd WEDC International Conference. Colombo: Sri Lanka, 13-17 November 2006.

De Silva CS, Weatherhead EK, Knox JW, Rodriguez-Diaz JA. 2007. Predicting the impacts of climate change: A case study of paddy irrigation water requirements in Sri Lanka. Agricultural Water management 93(1-2): 19-29. https://doi.org/10.1016/j.agwat.2007.06.003

De Silva MMGT, Weerakoon SB, Herath S, Ratnayake UR, Mahanama S. 2012. Flood inundation mapping along the lower reach of Kelani River basin under the impact of climatic change. Engineer: Journal of the Institution of Engineers Sri Lanka 45(2): 23–29.

http://doi.org/10.4038/engineer.v45i2.6938

De-Silva G, Weerakoon SB, Herath S. 2016. Event based flood inundation mapping under the impact of climate change: a case study in lower Kelani River basin, Sri Lanka. Hydrology: Current Research 7(1): 7–10.

Dharmarathna W, Herath S, Weerakoon S. 2012. Changing the planting date as a climate change adaptation strategy for rice production in Kurunegala district, Sri Lanka. Sustainability Science 9(1): 103-111. doi: 10.1007/s11625-012-0192-2

Dissanayaka K, Rajapakse R. 2019. Long-term precipitation trends and climate extremes in the Kelani River basin, Sri Lanka, and their impact on streamflow variability under climate change. Paddy and Water Environment 17(2): 281-289. doi: 10.1007/s10333-019-00721-6

Dorji S, Herath S, Mishra BK. 2017. Future Climate of Colombo Downscaled with SDSM-Neural Network. Climate 5(1-24): 1-11. https://www.mdpi.com/2225-1154/5/1/24

Dumitrescu A, Bojariu R, Birsan MV, Marin L. Manea A. 2015. Recent climatic changes in Romania from observational data (1961–2013). Theoretical and Applied Climatology 122: 111–119. https://doi.org/10.1007/s00704-014-1290-0

Eckstein D, Künzel V, Schäfer L, Winges M. 2019. Global Climate Risk Index 2020. Who suffers most from extreme weather events? Weather-related loss events in 2018 and 1999 to 2018. Germanwatch. Bonn. Germany.

Eriyagama N, Smakhtin V. 2010. Observed and projected climatic changes, their impacts and adaptation options for Sri Lanka: a review, in Proceedings of the National Conference on Water, Food Security and Climate Change in Sri Lanka. International Water Management Institute, Colombo.

Esham M, Garforth C. 2013. Climate change and agricultural adaptation in Sri Lanka: A review. Climate and Development 5(1): 66-76. DOI: 10.1080/17565529.2012.762333

Fernando TK, Chandrapala L. 1992. Global Warming and Rainfall Variability – Sri Lankan Situation. Proceedings of the 47th Annual Session of Sri Lanka Association for the Advancement of Science (SLASS).Section E1. pp 138

Fernando TK. 1997. Recent Variations of rainfall and air temperature in Sri Lanka. Proceedings of the 53rd Annual Session of Sri Lanka Association for the Advancement of Science (SLASS).Section E1. pp 138.

Gagnon S, Singh B, Rousselle J, Roy L. 2005. An Application of the Statistical DownScaling Model (SDSM) to Simulate Climatic Data for Streamflow Modelling in Québec. Canadian Water Resources Journal 30(4): 297-314. https://doi.org/10.4296/cwrj3004297

Gunasekara D, Yeon K, Catherine T, Melanie F. 2007. Climate change: impacts on Australian agriculture. Australian Commodities: Forecasts and Issues 14(4): 657–676.

DOI: https:/doi/10.3316/ielapa.970516347702109

Herath HMVV, Dayananda RGAB, Madakumbura MMGD, Priyankara WMS, Weerakon SB. 2016. WRF weather downscaling model coupled with runoff model for anticipatory flood water management of the Polgolla Barrage. 20th IAHR APD Congress in Colombo, Sri Lanka. 29-31 August 2016.

Hussain M, Yusof KW, Mustafa MRU, Afshar NR. 2015. Application of Statistical Downscaling Model (SDSM) for long Term Prediction of Rainfall in Sarawak, Malaysia. WIT Transactions on Ecology and the Environment 196: 269-278. DOI: 10.2495/WRM150231

Imbulana KAUS, Wijesekara NTS, Neupane BR. Eds. 2006. Sri Lanka National Water Development Report. MAI&MD, UN-WWAP, UNESCO and University of Moratuwa, Sri Lanka, Paris and New Delhi.

Imbulana N, Gunawaradana SK Shrestha, S, Datta A. 2018. Projections of Extreme Precipitation Events under Climate Change Scenarios in Mahaweli River Basin of Sri Lanka. Current Science 114(7): 1495-1509. DOI: 10.18520/cs/v114/i07/1495-1509.

IPCC. 2007: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE, Eds., Cambridge University Press, Cambridge, UK. Pp 976.

Jayatillake H. 2004. Will there be sufficient water under internal and external changes? Walawe Basin (Sri Lanka). In J. Aerts & P. Droogers, Climate change in contrasting river basins: adaptation strategies for water, food and environment Wallingford. UK: CABI. ix, pp 264.

Jayatillake HM, Chandrapala L, Basnayake BRSB, Dharmaratne GHP. 2005. Water Resources and climate change. Proceedings of Workshop on Sri Lanka National Water Development Report. Wijesekera NTS, Imbulana KAUS, Neupane B. Eds. World Water Assessment Programme (WWAP): Paris, France.

Jha M, Arnold JG, Gassman PW, Giorgi F, Gu RR. 2006. Climate change sensitivity assessment on upper Mississippi river basin streamflows using SWAT. Journal of the American Water Resources Association 42 (4): 997–1015. DOI: 10.1111/j.1752-1688.2006.tb04510.x

Jiang T, Chen YD, Xu CY, Chen X, Singh VP. 2007. Comparison of hydrological impacts of climate change simulated by six hydrological models in the Dongjiang basin, south China. Journal of Hydrology 336(3-4): 316–333. https://doi.org/10.1016/j.jhydrol.2007.01.010

Karunanayake C, Gunathilake MB, Rathnayake U. 2020. Inflow Forecast of Iranamadu reservoir, Sri Lanka, under Projected Climate Scenarios Using Artificial Neural Networks. Applied Computational Intelligence and Soft Computing 1-11, https://doi.org/10.1155/2020/8821627

Katul GG, Oren R, Manzoni S, Higgins C, Parlange MB. 2012. Evapotranspiration: process driving mass transport and energy exchange in the soil-plant-atmosphere-climate system. Review of Geophysics 50(3): 1-25. https://doi.org/10.1029/2011RG000366.

Khalid MM, Muhinadeen M, Weerakoon SB. 2017. Rainfall forecast in the Upper Mahaweli basin in Sri Lanka using RegCM model. Journal of Physics Conference Series 822 (1): 1-10. DOI: 10.1088/1742-6596/822/1/012075.

Khaniya B, Karunanayake C, Gunathilake MB, Rathnayake U. 2020. Projection of Future Hydropower Generation in Samanalawewa Power Plant, Sri Lanka. Mathematical Problems in Engineering. 1-11. https://doi.org/10.1155/2020/8862067

Khattak MS, Babel M, Sharif M. 2011. Hydro-meteorological trends in the upper Indus river basin in Pakistan. Climate research 46(2): 103-119. DOI:https://doi.org/10.3354/cr00957

Kundzewicz Z, Robson A. 2000. Detecting trend and other changes in hydrological data. United Nations Educational Scientific and Cultural Organization: World Meteorological Organization.

Malmgren BA, Hulugalla R, Hayashi Y, Mikami T. 2003. Precipitation Trends in Sri Lanka since the 1870s and Relationships to El NinoSouthern Oscillation. International Journal of Climatology 23(10):1235-1252. https://doi.org/10.1002/joc.921

Mann H. 1945. Non-parametric tests against trend. Econmetrica 13(3):245-259.

https://doi.org/10.2307/1907187

Ministry of Agriculture. 2018. Sri Lanka Council for Agriculture Research Policy, National Agricultural Research Policy and Strategy. ISBN 978-955-9224-67-9

Ministry of Environment Sri Lanka. 2011. Climate Change Vulnerability Data Book, Ministry of Environment: Colombo, Sri Lanka.

Muhinadeen M, Khalid MM, Weerakoon SB, Mutua F. 2016. Comparative study of WRF & RegCM weather predictions for the Upper Mahaweli river basin. 7th International Conference on Sustainable Built Environment 2016 (ICSBE 2016) Kandy. 16-18 December 2016.

Nagahamulla H, Ratnayake U, Ratnaweera A. 2014. Artificial neural network ensembles in time series forecasting: an application of rainfall forecasting in Sri Lanka. International Journal on Advances in ICT for Emerging Regions (ICTer) 6(2), DOI:10.4038/icter.v6i2.7151

Nagahamulla HRK, Ratnayake UR, Ratnaweera A. 2011. Monsoon rainfall forecasting Sri Lanka using artificial neural networks. 6th International Conference on Industrial and Information Systems. 305-309. doi: 10.1109/ICIINFS.2011.6038085

Nandalal KDW, Sachindra DA, Ratnayake UR. 2012. Application of WRF weather model to forecast precipitation in Nilwala river basin. Engineer 45(1): 51–64.

DOI:http://doi.org/10.4038/engineer.v45i1.6949

Perera A, Rathnayake U. 2019. Impact of climate variability on hydropower generation in an un-gauged catchment: Erathna run-of-the-river hydropower plant, Sri Lanka. Applied Water Science 9:1-11. https://doi.org/10.1007/s13201-019-0925-9-

Perera A, Ranasinghe T, Gunathilake M, Rathnayake U. 2020. Comparison of different analyzing techniques in identifying rainfall trends for Colombo, Sri Lanka. Advances in Meteorology 1-10, doi: 10.1155/2020/8844052

Premalal KHMS. 2009. Weather and Climate Trends, Climate Controls & Risks in Sri Lanka. Sri Lanka Monsoon Forum. April 2009. Department of Meteorology, Sri Lanka.

Premalal KHMS. 2013. Change and Behavior of Rainfall Pattern in Sri Lanka with Southern Oscillation (SO) - El Nino and La Nina, SAARC Meteorological Research Centre, Dhaka, Bangladesh

Punyawardena BVR, Cherry NJ. 1999. Assessment of the predictability of the seasonal rainfall in Ratnapura using southern oscillation and its two extremes. Journal of the National Science Council of Sri Lanka 27(3): 187–195.

Qin P, Xu H, Liu M, Xiao C, Liu L, Tarroja B. 2020. Climate change impacts on Three Gorges Reservoir impoundment and hydropower generation. Journal of Hydrology 580,

https://doi.org/10.1016/j.jhydrol.2019.123922

Rathnayake U. 2019. Comparison of statistical methods to graphical methods in rainfall trend analysis: case studies from tropical catchments. Advances in Meteorology 1-10.

https://doi.org/10.1155/2019/8603586

Ratnayake U, Herath S. 2005. Changing Rainfall and its Impact on Landslides in Sri Lanka. Journal of Mountain Sciences 2: 218–224. https://doi.org/10.1007/BF02973195

Ratnayake U, Sachindra DA, Nandalal KDW. 2010. Rainfall forecasting for flood prediction in the Nilwala basin. Proceedings of the International Symposium on Coastal Zones and Climate Change: Assessing the Impacts and Developing Adaptation Strategies, Monash University, Australia. 12–13 April 2010.

Ruwangika AM, Perera A, Rathnayake U. 2020. Comparison of statistical, graphical, and wavelet transform analyses for rainfall trends and patterns in Badulu Oya catchment, Sri Lanka. Complexity 1-13. https://doi.org/10.1155/2020/7146593

Sarathchandra C, Abebe Y, Wijerathne I., Aluthwattha S, Wickramasinghe S, Ouyang Z. 2021. An Overview of Ecosystem Service Studies in a Tropical Biodiversity Hotspot, Sri Lanka: Key Perspectives for Future Research. Forests 12(5): 1-16. DOI:10.3390/f12050540

Sen PK. 1968. Estimates of the regression coefficient based on kendall’s tau. Journal of the American Statistical Association 63(324): 1379–1389. https://doi.org/10.2307/2285891

Shantha WWA, Jayasundara JMSB. 2005. Study on Changes of Rainfall in the Mahaweli Upper Watershed in Sri Lanka due to Climatic Changes and Develop a Correction Model for Global Warming. Paper presented at the International Symposium on the Stabilization of Greenhouse Gas Concentrations. Hadley Centre, Met Office, Exeter, UK.

Sharannya TM, Mudbhatkal A, Mahesha A. 2018. Assessing climate change impacts on river hydrology – A case study in the Western Ghats of India. Journal of Earth System Sciences 127:1-11. https://doi.org/10.1007/s12040-018-0979-3

Simonovic SP, Li L. 2003. Methodology for assessment of climate change impacts on large-scale flood protection system. Journal of Water Resources Planning and Management 129: 361–372.

https://doi.org/10.1061/(ASCE)0733-9496(2003)129:5(361)

Sumathipala WL, Punyadeva NBP. 1998. Variation of the rainfall of Sri Lanka in relation to El Nino. In Proceedings of the Annual Sessions of the Institute of Physics, Sri Lanka, Colombo.

Taylor IH, Burke E, McColl L, Falloon PD, Harris GR, McNeall D. 2013. The impact of climate mitigation on projections of future drought. Hydrology and Earth System Sciences 17(6): 2339–2358. https://doi.org/10.5194/hess-17-2339-2013

Teutschbein C, Seibert J. 2010. Regional climate models for hydrological impact studies at the catchment scale: a review of recent modeling strategies. Geography Compass 4(7):834–860.

https://doi.org/10.1111/j.1749-8198.2010.00357.x

Thambyahpillay G. 1954. The rainfall rhythm in Ceylon. University of Ceylon Review, vol. XII, 4: 224-273. http://hdl.handle.net/123456789/1016

Trenberth KE, Jones PD, Ambenje P, Bojariu R, Easterling D, Klein TA, Parker D, Rahimzadeh F, Renwick JA, Rusticucci M, et al. 2007. Observations: surface and atmospheric climate change. In Climate Change 2007. The Physical Science Basis, Contribution of WG 1 to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Solomon S, Qin D, Manning M, Chen Z, Marquis MC, Averyt KB, Tignor M, Miller HL, (Eds.), Cambridge University Press, Cambridge, New York.

Vihma T, Screen J, Brandi Tjernström M, Newton B, Zhang X, Popova V, Deser C, Holland M, Prowse T. 2016. The atmospheric role in the Arctic water cycle: A review on processes, past and future changes, and their impacts. Journal of Geophysical Research Biogeosciences 121(3). DOI: 10.1002/2015JG003132

Wickramagamage P. 2010. Seasonality and spatial pattern of rainfall of Sri Lanka: Explanatory factor analysis. International Journal of Climatology 30(8): 1235–1245. https://doi.org/10.1002/joc.1977

Wilby RL, Dawson CW, Barrow EM. 2002. SDSM – A Decision Support Tool for the Assessment of Regional Climate Change Impacts. Environmental Modelling & Software 17: 147-159.

Withanachchi S, Köpke S, Withanachchi CR, Pathiranage R, Ploeger A. 2014. Water Resource Management in Dry Zonal Paddy Cultivation in Mahaweli River Basin, Sri Lanka: An Analysis of Spatial and Temporal Climate Change Impacts and Traditional Knowledge. Climate 2(4): 329-354. doi:10.3390/cli2040329

Zhang X, Yang F. 2004. Rclimdex (1.0) User Manual. Climate Research Branch Environment Canada. Available at https://acmad.net/rcc/procedure/RClimDexUserManual.pdf


Refbacks

  • There are currently no refbacks.


Creative Commons Licence
Ruhuna Journal of Science by University of Ruhuna is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

eISSN: 2536-8400

Print ISSN: 1800-279X (Before 2014)