Document Type : Research Article

Authors

1 Gorgan University of Agricultural Sciences and Natural Resources

2 Ferdowsi University of Mashhad

3 Golestan University

Abstract

Characteristics of precipitation and the regionalization major role in the efficient use of water resources and soil and management of environmental hazards. Regionalization of rainfall can help to better use of water resources and to correct manage of environmental hazards. According to the analysis of climate phenomena such as precipitation, all data should be related to a homogeneous region, on the basis in this study, homogenous regions using data from long-term annual precipitation in Golestan province and the appropriate number of stations determined using the newer methods. Precipitation monthly data from 29 rain-gauge stations and evaporation poll in Golestan province from 1361 to 1391 were used to testing of homogeneity, the random and outlier data that 25 stations remained. Then using Wards hierarchicalclustering and with different variables was evaluated segmentation varies. Clustering in two clusters have higher average silhouette 0.48, accordingly, the province was divided into two regions. Homogeneity investigated by heterogeneity test for each region. according to investigations was performed by L- moments coefficient of skewness (τ_3^R) was smaller 0.23, The result Hosking and Wallis test was used to examine the homogeneity region. For this two region, the test statistic H11>, which is confirmed by the homogeneity of the two areas, Finally was divided into two regions. The high correlation coefficient between stations in each cluster and low correlation coefficient between two different cluster is another reason for separation of areas from each other.Characteristics of precipitation and the regionalization major role in the efficient use of water resources and soil and management of environmental hazards. Regionalization of rainfall can help to better use of water resources and to correct manage of environmental hazards. According to the analysis of climate phenomena such as precipitation, all data should be related to a homogeneous region, on the basis in this study, homogenous regions using data from long-term annual precipitation in Golestan province and the appropriate number of stations determined using the newer methods. Precipitation monthly data from 29 rain-gauge stations and evaporation poll in Golestan province from 1361 to 1391 were used to testing of homogeneity, the random and outlier data that 25 stations remained. Then using Wards hierarchicalclustering and with different variables was evaluated segmentation varies. Clustering in two clusters have higher average silhouette 0.48, accordingly, the province was divided into two regions. Homogeneity investigated by heterogeneity test for each region. according to investigations was performed by L- moments coefficient of skewness (τ_3^R) was smaller 0.23, The result Hosking and Wallis test was used to examine the homogeneity region. For this two region, the test statistic H11>, which is confirmed by the homogeneity of the two areas, Finally was divided into two regions. The high correlation coefficient between stations in each cluster and low correlation coefficient between two different cluster is another reason for separation of areas from each other.

Keywords

1- خام چین مقدم ف.، صدقی ح.، کاوه ف. و منشوری م. 1389. پهنه‏بندی حداکثر بارش روزانه ایران. نشریه آب و خاک مشهد، جلد 24، شماره 1، ص 106-97.
2- دودانگه ا.، اختصاصی م.ر. و شایق ا. 1392. کاربرد گشتاورهای خطی در تحلیل فراوانی منطقه‏ای و پهنه‏بندی بادهای فرساینده در ایران. علوم و مهندسی آبخیزداری ایران، جلد 7، شماره 23، ص 41-33
3- رضایی پژند ح .1380. کاربرد آمار و احتمال در منابع آب. انتشارات سخن گستر، 458 صفحه.
4- مساعدی ا.، شریفان ح. و شهابی م. 1386. طرح پژوهشی مدیریت ریسک با شناخت میکروکلیماهای استان گلستان. سازمان هواشناسی کشور، 171 ص.
5- Abdolhay A., Saghafian B., Mohd Soom M. and Ghazali A. 2012. Identification of homogenous regions in Gorganrood basin (Iran) for the purpose of regionalization. Natural Hazards, 61:3. 1427-1442.
6- Abolverdi J., and Khalili D. 2010. Development of regional rainfall annual maxima for soutwestern Iran by L-moments. Water Resour Manage, 24:2501-2526.
7- Chow V.T., Maidment D.R. and Mays L.W. 1988. Applied Hydrology, McGraw –Hill, New York., 572 pp.
8- Dinpashoh Y., Fakheri-Fard A., Moghaddam M., Jahanbakhsh S. and Mirnia M. 2003. Selection of variables for the purpose of regionalization of Iran's percipitation climate using multivariate methods, J. Hydrol, 297:109-123.
9- Eslamian S.S. and Chavoshi-Boroujeni S. 2001. The study of hydrological homogeneity in gauged watersheds of central part of Iran. Sci J Agric, 23:1–30.
10- Guttman N.B. 1993. The use of L-Moments in the determination of regional precipitation climates. J.Climate, 6:12. 2309 – 2325.
11- Gwo-Fong L. and Lu-Hsien C. 2006. Identification of homogeneous regions for regional frequency analysis using the self-organizin g map. J. Hydrology, 324: 1-9.
12- Hosking J.R.M. and Wallis J.R. 1991. Some statistics useful in regional frequency analysis, Res. Rep. RC 17096, IBM Research Division,Yorktown Heights, NY 10598.
13- Hosking J.R.M. and Wallis J.R. 1993. Some statistics useful in regional frequency analysis, Water Resources Res. 29:271-281.
14- Hosking J.R.M. and Wallis J.R. 1997. Regional frequency analysis: an approach based on L-moments., Cambridge University Press, New York , USA.217pp.
15- Kalkstein L.S., Tan G., and Skindlov J.A. 1987. An evaluation of three clustering procedures for use in synoptic climatological classification. J. Climatol. Appl. Meteorol. 26:717–730.
16- Maechler M., Rousseeuw P., Struyf A., Hubert M., and Hornik K. 2012. cluster: Cluster Analysis Basics and Extensions. R package version 1.14.3.
17- National Drought Mitigation Center of United States (NDMC). 1998. Report on drought related effects of El Niño.
18- Ramos M.C. 2001. Divisive and hierarchical clustering techniques to analyze variability of rainfall distribution patterns in a Mediterranean region. J. Hydrology, 57:123–138.
19- Rao A.R. and Hamed K.H. 2000. Flood Frequency Analysis, CRC Press.
20- Rousseeuw P.J. 1987. Silhouette: A graphical aid to the interpretation and validation of cluster analasis, Journal of Computational and Applied Mathematics, 20:53-65.
21- Team R.C. 2012. R: A language and environment for statistical computing. R Foundation for Statistical Computing. http://www.R-project.org/.
22- Viglione A., Laio F. and Claps P. 2007. A comparison of homogeneity tests for regional frequency analysis, Water Resour. Res., 43, W03428.
23- Viglione A. 2012. homtest: Homogeneity tests for Regional Frequency Analysis. R package version 1.0-5. http://CRAN.R-project.org/package=homtest
24- Viglione A. 2013. nsRFA: Non-supervised Regional Frequency Analysis. R package version 0.7-11. http://CRAN.R-project.org/package=nsRFA
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