Applied Research in Geographical Sciences

Applied Research in Geographical Sciences

Analysis of inter-decade changes in trends and spatial patterns of annual and seasonal precipitation, case study: West of Iran

Authors
Fatemeh Ghiasabadi Farahani 1
Faramarz khoshakhlagh 2
Aliakbar Shamsipour 3
Ghasem Azizi 4
ebrahim fattahi 5
1 Ph.D. student of Climatology, University of Tehran, iran
2 Assistant professor Climatology, University of Tehran. iran
3 Assistant professor Climatology, University of Tehran, iran
4 Associate professor of Climatology, university of Tehran, iran
5 Associate Professor of Geography of the Meteorological Institute, tehran, iran
10.29252/jgs.18.48.59
Abstract
The present research about the spatial changes of precipitation is mainly focused on western areas of Iran. Precipitation data for three seasons of fall, winter, and spring have been obtained from Esafzari Database, with 15*15 km spatial resolution in the form of a Lambert Cone Image System for the period from 1986 to 2015. To examine the prevailing pattern of precipitation in west of Iran, we have used geostatistical methods of spatial autocorrelation. The changes in precipitation trends have been analyzed using parametric and non-parametric analyses of regression and Mann Kendal. We have used MATLAB for analysis of the data. We have also used ArcGIS and Surfer for drawing maps. The results of inter-decade changes of positive spatial autocorrelation of precipitation in west of Iran have indicated that there has been a decline in spatial extent of the positive spatial autocorrelation pattern in spring and fall, except for winter with a negligible increasing trend. Nevertheless, except for the second period, no considerable spatial changes were observed in the spatial pattern of precipitation in the region. However, there was a decreasing trend in the negative spatial autocorrelation of precipitation in annual and seasonal scales. The results of trend analysis have indicated that there was a decreasing trend in a vast area of the west parts of the country in annual scale and also in winter. Although there was an increasing trend in precipitation in fall and spring, but the trend was not significant in 95 % of confidence interval. The results of Man Kendal test have confirmed the results obtained from linear regression.
Keywords
Precipitation
spatial auto-correlation pattern
regression
Mann Kendall
in western areas of Iran
-Akinremi, O. O., MC Ginn S.M. and Cutforth, H.W. (2001) Seasonal and Spatial Patterns of Rainfall Trends on the Canadian Prairies,Journal of climate, vol.14,Issue9, pp.2177-2182.
-Chen j., Wub X., Finlayson B., Webber M., Wei T., and Li M. (2014) Variability and trend in the hydrology of the Yangtze River, China: Annual precipitation and runoff. Journal of Hydrology. 513: 403-412.
-Diop L., Bodian A., and Diallo D. (2016) Spatiotemporal trend analysis of the mean annual rainfall in Senegal. European scientific journal, vol.12. No.12, pp.231-245.
-Gemmer M., S. Becker and T. Jiang (2004) Observed Monthly Precipitation Trends in China 1951-2002. Theor. Appl. Climatol. 77.
-Haigh, M.J. (2014) Sustainable management of head water resources: the Nairobi headwater declaration (2002) and beyond. Asian J. Water, Environ. Pollut. 1(1–2), 17–28.
-Langat, P.K.; Kumar, L.; Koech, R. (2017) Temporal Variability and Trends of Rainfall and Streamflow in Tana River Basin, Kenya. Sustainability, 9, 1963.
-Merabtene T., Siddique M., and Abdallah Sh. (2016) Assessment of Seasonal and Annual Rainfall Trends and Variability in Sharjah City, UAE, Advances in Meteorology, vol., Article ID 6206238, 13 pages.
-Mercy, I. C. (2015) Trend analysis of rainfall pattern in Enugu state, Nigeria. European Journal of Statistics and Probability Vol.3, No.3, pp.12-18.
-Mozafari, G., Shafiei, Sh. (2016) Analysis annual trend of precipitation in western regions of Iran, Journal of Applied Research of Water Sciences, Second Year, No. 1, pp. 49-58.
-Tabari, H. and Hosseinzadeh Talaee, P. (2011) Temporal variability of precipitation over Iran: 1966–2005, Journal of Hydrology, 396: 313-320.
-Tabari, H., Taye, M. T. & Willems, P. (2015) Statistical assessment of precipitation trends in the upper Blue Nile River basin Stoch Environ Res Risk Assess. DOI 10.1007/s00477-015-1046-0.
-Taxak A.K., Murumkar A.R., Arya D.S. (2014) Long term spatial and temporal and homogeneity analysis in Wainganga basin, Central India.Weather and Climate Extremes 4, 50-61.
-Zang Q., Jiang T., Gemmer M., Becker S. (2005) precipitation, temperature and run off analysis from 1950 to 2002 in the Yangtze basin, China, J Hydrol Sci 50:65-80.