Investigating the trend and time of precipitation and river flow rate changes in Lake Urmia basin, Iran
- 13 Downloads
In this study, the trend of precipitation and river flow rate changes in Lake Urmia basin (LUB) were investigated at two monthly and annual scales using the modified Mann-Kendall test (MMK) with complete removal of autocorrelation process. To this purpose, 42 rain gauge and 25 hydrometric stations were selected in Lake Urmia basin during the statistical period of 1984–2013. The results of studying the precipitation changes in the LUB indicated that this basin experienced a combination of decreasing and increasing trend during the studied statistical period. The decreasing precipitation trend was often observed at west and southwest stations of the basin. The increasing trend was observed in the southern and northeastern regions. The results of studying the changes in river flow rate of the studied stations in the LUB indicated that the trend of river flow rate is decreasing in most of the months. At an annual scale, the decreasing trend of river flow rate was also clearly observed across the basin at all stations. In addition, the decreasing trend of river flow rate is more severe in autumn and winter. The results of studying the time of changing point in the precipitation series showed that the time of changing point occurred between 1992 and 1998 at most of the stations that experienced a decreasing precipitation trend. The time of changing point of river flow rate in LUB occurred between 1994 and 1998. Two years after the reductions in precipitation, the decreasing trend of river flow rate occurred in the rivers.
KeywordsModified Mann-Kendall Lake Urmia Trend Pettitt test
The authors would like to thank West Azerbaijan Regional Water Authority for providing the data.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Dixon H, Lawler DM, Shamseldin AY (2006) Streamflow trends in western Britain. Geophys Res Lett 33(L19406):1–7Google Scholar
- Duan K, Yao T, Thompson LG (2006) Response of monsoon precipitation in the Himalayas to global warming. J Geophys Res: Atmospheres 111(D19110):1–8Google Scholar
- Ghahraman B, Taghvaeian S (2008) Investigation of annual rainfall trends in Iran. J Agric Sci Technol 10:93–97Google Scholar
- Hasan Z, Akhter S, Islam M (2014) Climate change and trend of rainfall in the south-east part of coastal Bangladesh. Eur Sci J ESJ 10(2):25–39Google Scholar
- Kendall M (1975) Rank correlation measures [M]. Charles Griffin, LondonGoogle Scholar
- Khalili K, Nazeri Tahrudi M, Khanmohammadi N (2014) Trend analysis of precipitation in recent two decade over Iran. J Appl Environ Biol Sci 4(1s):5–10Google Scholar
- Mann HB (1945) Nonparametric tests against trend Econometrica. J Econ Soc 13:245–259Google Scholar
- Rowshan G, Mohammadi H, Nasrabadi T, Hoveidi H, Baghvand AJIJER (2007) The role of climate study in analyzing flood forming potential of water basins. International Journal of Environmental Research 1(3):231–236Google Scholar
- Shen Y, Wang S, Wang G, Shao C, Mao W (2006) Response of glacier flash flood to global warming in Tarim River basin. Adv Clim Chang Res 2(1):32–35Google Scholar
- Tisseuil C, Roshan GR, Nasrabadi T, Asadpour GJIJER (2013) Statistical modeling of future lake level under climatic conditions, case study of Urmia Lake (Iran). Int J Environ Res 7(1):69–80Google Scholar