Investigating the effects of climate change on torrential rains in Tehran province

Document Type : Research/Original/Regular Article

Authors

1 Professor/ Department of Climatology, Faculty of Geographical Sciences, Kharazmi University, Tehran, Iran

2 Associate Professor/ Department of Climatology, Faculty of Geographical Sciences, Kharazmi University, Tehran, Iran

3 Associate Professor/Department of Geography and Urban Planning, Faculty of Geographical Sciences, Kharazmi University, Tehran

4 Graduated Ph.D. Student/ Department of Climatology, Tarbiat Modares University, Tehran, Iran

5 Graduated M.Sc. Student/ Department of Geomorphology, Faculty of Geographical Sciences, Kharazmi University, Tehran, Iran

Abstract

Introduction
The phenomenon of climate change and global warming is one of the biggest challenges of the present age, which has affected the hydrological cycle on a global and regional scale. The purpose of this study is to investigate the effects of climate change on torrential rains And Temprature, Rainfall, Run off  in Tehran province. In this study, changes in torrential rainfall in Tehran and the frequency and intensity of torrential rainfall in the future and climate change and the rate of increase of floods on periodic floods have been investigated.
Materials and Methods
This research has been done in two study discussions (meteorological, hydrological). First, parameters (temperature and precipitation) for synoptic stations (Abali, Shemiran, Mehrabad) for the period (1988-2020) were received from the Meteorological Organization and rainfall and runoff data from hydrometric stations were received from the Tehran Regional Water Authority. Down Scaling model and methods in this research SDSM-DC, Mann-Kendall, Rclimdex, XLSTAT, to simulate future floods and SMADA, HEC-HMS model to simulate floods in current and future periods have been used.
Results and Discussion
The results showed that the temperature extreme indices in all stations had an increasing trend and the precipitation indices had an increasing trend only in Abali station. But rainfall in Shemiran and Mehrabad stations had a decreasing trend. Examination of rainfall changes using Mann-Kendall test in most months of the year shows a stable trend and jumps are observed in the rainy months, which can be justified by the increase in rainfall frequency. In the CanESM Model 2 simulation, emphasizing the RCP8.5 release scenario, an increasing temperature trend was observed for the coming decades. The highest temperature increase belongs to Mehrabad station with an average temperature increase of 5.1 percent for the period 2021-2083. The highest rainfall for all three stations is estimated in March next year. Therefore, with the increase of temperature trend, changes in the type of precipitation have occurred, which can be affected by urban microclimate. Simulation of the rainfall-runoff model of the basin with the HEC-HMS model showed that the volume of discharge in the future will be reduced by 5 percent and for return periods, the maximum discharge is estimated at 1501.7 cubic meters.
Conclusion
Due to Rainfall behavior is expected to increase in the coming decades, while reducing its fluctuations. It is predicted that the climate of Tehran in the future will have more fluctuations in precipitation and warmer than the current situation, and this increase and frequency of precipitation is likely to increase flood frequency and reinforce its occurrence, while rainfall will occur more accidentally but with greater intensity, leading to environmental and urban hazards.

Keywords


Aghabeigi, N., Esmali Ouri, A., Mostafazade, R., & Golshan, M. (2019). The effects of climate change on runoff using IHACRES hydrologic model in some of watersheds, Ardabil Province. Irrigation and Water Engineering, 10(2), 178-189. (in Persian).
Ahmadabadi, A., & Sedighifar, Z. (2018). Predicting the effects of climate change on the hydrogeomorphological characteristics of the catchment based on a statistical microscale model. Applied Research in Geographical Sciences (Geographical Sciences), 18 (51), 103-114. (in Persian).
Ahmadi, H., Rostami, N., & Dadashi-roudbari, A. (2020). Projected climate change in the Karkheh Basin, Iran, based on CORDEX models. Theoretical and Applied Climatology, 142(1), 661-673.
Alavinia, S.H., & Zarei, M. (2021). Analysis of spatial changes of extreme precipitation and temperature in Iran over a 50‐year period. International Journal of Climatology, 41, E2269-E2289.
AliMohammadi, A. (2009). Natural resource and environmental studies, Climate Status Analysis, Tehran Governorate. Final report, Deputy of Planning (in Persian).
AliMohammadi, A. (2009). Natural resource and environmental studies water resources analysis. Final report, Deputy of Planning (in Persian).
Bai, Y., Zhang, Z., & Zhao, W. (2019). Assessing the impact of climate change on flood events using HEC-HMS and CMIP5. Water, Air, & Soil Pollution, 230(6), 119.
Barati, Z., & Nasiri, M. (2011). Effects of human activities on flooding in Tehran: A case study of Darband and Golabdereh basins. First national conference on spatial analysis of environmental hazards in Tehran, University of Tehran (in Persian).
Beitulahi, A. (2019). Tehran flood risk and priority measures required. Final report, Seismology Center, Road, Housing and Urban Development Research Center (in Persian).
Climatology and Meteorology Working Group (2020). National flood studies, Iran (in Persian).
Darand, M. (2020). Predicting and modeling Iran's climate change using the SDSM statistical microscale model and various RCP scenarios. Final report of research project, University of Kurdistan (in Persian).
Dissanayaka, K.D.C.R., & Rajapakse, R.L.H.L. (2019). Long-term precipitation trends and climate extremes in the Kelani River basin, Sri Lanka, and their impact on streamflow variability underclimatechange. Paddy and Water Environment, 17(2), 281- 289.
Doulabian, S., Golian, S., Toosi, A.S., & Murphy, C. (2021). Evaluating the effects of climate change on precipitation and temperature for Iran using RCP scenarios. Journal of Water and Climate Change, 12 (1), 166-184.
Einali, S. (2017). A Review of Tehran Metro Flood Incident April 2012. 8th International Health Congress on Accidents and Disasters, Ministry of Health (in Persian).
Fathian, F., Ghadami, M., Haghighi, P., Amini, M., Naderi, S., & Ghaedi, Z. (2020). Assessment of changes in climate extremes of temperature and precipitation over Iran. Theoretical and Applied Climatology, 141, 1119-1133.
Fahiminejad, A., Baeqideh, M., Babaian, A., & Entezari, A. (2019). Simulation of the effect of global warming on the mean and limit events of some hydro-climatic variables in the Shandiz catchment, Journal of Spatial Analysis of Environmental Hazards, 3, 27-48 (in Persian).
Gao, C., He, Z., Pan, S., Xuan, W., & Xu, Y.P. (2020). Effects of climate change on peak runoff and flood levels in Qu River Basin, East China. Journal of Hydro-Environment Research, 28, 34-47.
Habibnejad, R., & Shokoohi, A . (2020). Evaluating intensity, duration and frequency of short duration rainfalls using a regional climate change model (Case study: Tehran). Iran-Water Resources Research, 15(4),  412–424 (in Persian).
Hejazizadeh, Z., Fattahi, A., Massah Boani, A., & Naserzadeh, M. (2012). Assessing the effects of climate change on flood hydrography in future periods Case study: Bakhtiari catchment. Geography, 10 (34), 24-5 (in Persian).
Hejazizadeh, Z., & Parvin, N. (2009). Investigation of temperature and precipitation changes in Tehran during the last half century. Geography and Regional Planning, 1 (prefix), 43-56.  (in Persian).
Hosseini, A. (2014). Determination of spatial indicators of flood potential using HEC-HMS hydrological model Case study (Taleghan watershed). M.Sc. Thesis, Kharazmi University of Tehran, Tehran, Iran (in Persian).
IPCC (2021). Climate Change, Sixth Assessment Report.
Kordjazi, M.,  Bagherian, S., Babaian, I., & Kamali, A.  (2014). Investigation of the effects of climate change on floods in Golestan province. 5th International conference on comprehensive management of natural crises, Permanent Secretariat of the Comprehensive Crisis Management Conference (in Persian).
Mathbout, S., Lopez-Bustins, J.A., Royé, D., Martin-Vide, J., Bech, J., & Rodrigo, F. S. (2018). Observed changes in daily precipitation extremes at annual timescale over the Eastern Mediterranean during 1961–2012. Pure and Applied Geophysics, 175(11), 3875-2890.
Mostafazadeh, R., Sadoddin, A., Bahremand, A. Bardi Sheikh, W., Farming, A. (2017). Scenario analysis of flood control structures using a multi-criteria decision-making technique in Northeast Iran. Natural Hazards, 87(3), 1827-1846.
Myhre, G., Alterskjær, K., Stjern, C.W., Hodnebrog, Ø., Marelle, L., Samset, B.H., & Stohl, A. (2019). Frequency of extreme precipitation increases extensively with event rareness under global warming. Scientific Reports9(1), 1-10.
Papalexiou, S. M., & Montanari, A. (2019). Global and regional increase of precipitation extremes under global warming. Water Resources Research, 55(6), 4901-4914.
Rojpratak, S., Thani, P., Sudprasert, C., Aribarg, T., Supharatid, S., & Change, C. (2020). Hot spot Of climate extreme events (Floods and Drouhgts) in Thailand for a changing climate. Proceedings of the 22nd IAHR-APD Congress, Sapporo, Japan.
Rahimi, J., Malekian, A., & Khalili, A. (2019). Climate change impacts in Iran: assessing our current knowledge. Theoretical and Applied Climatology, 135(1-2), 545-564.
Saddique, N., Khaliq, A., & Bernhofer, C. (2020). Trends in temperature and precipitation extremes in historical (1961–1990) and projected (2061–2090) periods in a data scarce mountain basin, northern Pakistan. Stochastic Environmental Research and Risk Assessment, 34 (10), 1441-1455.
Sheikh Biklo Islam, B. (2021). Evidence and consequences of the flood event in Iran from prehistoric times to the present. Water and soil modeling and management, 1(1), 24-39. (in Persian).
Talchabhadel, R., Aryal, A., Kawaike, K., Yamanoi, K., & Nakagawa, H. (2021). A comprehensive analysis of projected changes of extreme precipitation indices in west rapti river basin, Nepal under changing climate. International Journal of Climatology, 41, E2581-E2599.
User Manual SDSM 4.2. (2002). A decision support tool for the assessment of regional climate change impacts.
Vaghefi, S.A., Keykhai, M., Jahanbakhshi, F., Sheikholeslami, J., Ahmadi, A., Yang, H., & Abbaspour, K. C. (2019). The future of extreme climate in Iran. Scientific Reports, 9(1), 1-11.
Zareie, Sh., Hazbavi, Z., Mostafazadeh, R., & Esmailori, A. (2020). Comparison of vulnerability of Samian watershed based on climate change. Natural Geography Research (Geographical Research), 52(2), 217-236 (in Persian).