Evaluation of climate variables impact on Kohrang River discharge (main branch of North Karoun River)

Document Type : Research Paper

Abstract

Kohrange sub-catchment is one of the main sources of North Karoun River. Climate variables, such as precipitation and temperature might have considerable impact on discharge of North Karoun River. To evaluate the impact of these variables, 27 years climate data were used. For this purpose, the mean of last ten years of 8 variables including, annual mean, max and min temperatures, number of snowy and rainy days, amount of annual rainfall, max daily rainfall intensity at Kohrang station and discharge of Dezak hydrometric station over mean previous years were evaluated and analyzed using Mann-Candall and Sen’s estimator methods. The above statistical methods showed that the mean annual temperature has increased by 1.5 degrees Celsius compared to mean of previous years at the level of 95 percent confidence interval, but the max and min annual temperatures did not show a statistically significant trend. Although, the max daily rainfall intensity and the number of snowy and rainy days have reduced annually, but these tests did not show a statistically significant trend either. The above mentioned statistical tests confirmed decreasing trends in annual precipitation by 11 percent (155.4 mm/year) and 19.7 percent in discharge at Dezak hydrometric station.

Keywords

• discharge
• precipitation
• rainfall intensity
• temperature

20.1001.1.20086377.1398.12.41.9.7

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References

1)       Abu-Taleb, A.A., Alawneh, AJ. and Smadi, M. 2007. Statistical analysis of recent changes in relative humidity in Jordan. American Journal of Environmental Sciences. 3(2): 75-77.

2)       Azizi, Gh., Karimi Ahmadabad. M. and Sabokkhiz Z. 2005. The temperature trend of Iran in recent decades and the increase in CO2, Journal of Geographic Sciences, Tarbiat Moallem University. 4(5): 53-43. (In Farsi)

3)       Bell, V.A., Kay, AL., Davies, H. N. and Jones, R.G. 2016. An assessment of the possible impacts of climate change on snow and peak river flows across Britain. Climatic Change. 136(3): 539–553.

4)       EPA (U.S. Environmental Protection Agency). 2011. Climate Change Handbook for Regional Water Planning. Washington, DC, U.S. Environmental Protection Agency, Climate Ready Estuaries Program. EPA 430-F-08-024.

5)       Hashemi, S.A., fatahi, R. and Abdollahi S. 2014. Drought Trend Assessment by Means of Nonparametric Man-Kendall test (case study: northern Karun river basin). Second National Conference On Water Crisis, Shahrekord. Shahrekord University. p 326.

6)       I.R. of IRAN Meteorological Organization. Chaharmahal Va Bakhtiari Meteorological Headquarter., 2014. Daily and monthly data. http://www.chaharmahalmet.ir/

7)       I.R. of IRAN Meteorological Organization. Chaharmahal Va Bakhtiari Meteorological Headquarter., 2010. Analysis of the Drought of 2010-2011 in Chaharmahal and Bakhtiari Province, Report of the Applied Meteorology Research Center.

8)       Islam, S., Rehman, N. and Sheikh, MM. 2009. Future change in the frequency of warm and cold spells over Pakistan simulated by the PRECIS regional climate model, 94(1), 35–45.

9)       Javari, M. 2001. Temporal changes in temperature and precipitation in Iran (PhD thesis). Tehran University.

10)   Katiraei Brojerdi, P.S., Hajjam S., Irannejad P. and Yosefi, N. 2007. Investigation of long-term changes in rainfall and rainy days in the west and northwest of Iran. The twelfth Geophysic Conference, Geology Organization, Tehran. (In Farsi)

11)   Kendall, M.G. 1975. Rank correlation methods. Griffin, London, UK.

12)   Kharin,V.V., Zwiers, F.W., Zhang, X. and Wehner, M.  2013. Changes in temperature and precipitation extremes in the CMIP5 ensemble. Climatic Change: 119(2): 345–357.

13)   Lettenmaier, D.P., Wood, E.F. and Wallis J.R. 1994. Hydro-climatological trends in the continental United States 1948-88. Journal of Climate. 7:586-607.

14)   Mann, H.B. 1945. Nonparametric tests against trend. Econometrica. 13: 245–259.

15)   Metz, B., Davidson, O.R., Bosch, P.R., Dave, R. and Meyer, LA. 2007. Climate change 2007d: Mitigation of Climate Change, Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4 WG3). Cambridge University Press, UK.

16)   Onoz, B. and Bayazit, M. 2012. The power of statistical tests for trend detection. Turkish Journal of Engineering and Environmental Sciences. 27: 247 – 251.

17)   Pachauri, R.K. and Reisinger, A. 2007. Climate change: Synthesis Report, Contribution of Working Groups I, II and III to the Fourth, Core Writing Team, Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4 SYR), IPCC,ISBN92-9169-122-4.

18)   Parry, M.L., Canzianim O.F., Palutikof, JP.,Van Der Linden, PJ., and Hanson, C.E. 2007. Climate Change 2007c: Impacts, adaptation and vulnerability, Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4 WG2), Cambridge University Press, ISBN978-0-521-88010-7  (pb: 978-0-521-70597-4).

19)   Partal, T., and Kahya, E. 2006. Trend analysis in Turkish precipitation data. Hydrological Processes. 20: 2011-2026.

20)   Sen, P.K. 1968. Estimates of the regression coefficient based on Kendall's tau. Journal of the American Statistical Association, v. 39, p. 1379 – 1389

21)   Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis M., Averyt KB., Tignor M. and Miller, H.L. 2007. IPCC, 2007: Summary for Policymakers. In: Climate Change 2007. The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge: Cambridge University Press. UK. 

22)   Sorribas, M.V., Paiva, RCD., Melack, J.M., Bravo, JM., Jones, C., Carvalho, L., Beighley, E., Forsberg, B. and Costa, M.H. 2016. Projections of climate change effects on discharge and inundation in the Amazon basin. Climatic Change. 136(3): 555–570.

23)   Tabari, H., Marofi, S., Aeini, A., Talaee, P.H. and Mohammadi, K. 2011. Trend Analysis of Reference Evapotranspiration in the Western half of Iran. Agricultural and Forest Meteorology. 151: 128-136.

24)    The nature conservancy, 2015. The science of climate change is complex, but everyone should know the basics.

25)   Theil, H. 1950. A rank-invariant method of linear and polynomial regression analysis. I, II, III, Nederl. Akad. Wetensch., Proc. 53: 386–392.

26)   Woolway, I., Marszelewski, C.W., Schmid  M., Bouffard D. and Merchant C.J. 2017. Warming of Central European lakes and their response to the 1980s climate regime shift. Climatic Change. 142(3): 505–520.