Trend Analysis in Reference Evapotranspiration Using Mann-Kendall and Spearman’s Rho Tests in Arid Regions of Iran
Trend Analysis in Reference Evapotranspiration Using Mann-Kendall and Spearman’s Rho Tests in Arid Regions of Iran
复制标题
DOI：
10.1007/s11269-011-9913-z
复制
发表时间：
2011
影响因子：
4.3
通讯作者：
M. Shadmani;S. Marofi;Majid Roknian
中科院分区：
文献类型：
--
作者：
M. Shadmani;S. Marofi;Majid Roknian
本研究调查了伊朗干旱地区参考蒸散量(ET0)的时间趋势。为此，使用了41年(1965-2005)11个高质量气象站点的气象观测数据，并使用非参数Mann-Kendall(MK)和Spearman‘s Rho(SR)检验在5%的显著水平上检验了ET0在月、季和年时间基础上的统计显著趋势。为了消除序列相关性对测试结果的影响，采用了无趋势预白化(TFPW)方法。研究结果表明，部分城市ET0呈上升(正)趋势，而部分城市ET0呈下降(负)趋势。在每个月的时间尺度上，ET0的显著趋势发生在Birjand最多，但在Bandarabbas、Sabzevar和Semnan站点没有观察到明显的趋势。在年度时间尺度上，马什哈德显示出最高的积极趋势(每年7.5毫米)。另一方面，伊斯法罕ET0的下降(负)趋势最大，−为6.38亿mm/年。总体而言，MK测验和SR测验的成绩和能力在检验显著水平上是一致的。
In this research, temporal trends of reference evapotranspiration (ET0) values were investigated in arid regions of Iran. For this purpose, meteorological observations collected from 11 high quality meteorological sites over a 41-year period (1965–2005) were used and statistically significant ET0 trends in the monthly, seasonal and annual time basis were detected using nonparametric Mann-Kendall (MK) and Spearman’s Rho (SR) tests at the 5% significant level. To eliminate the effect of serial correlation on the test results, the Trend Free Pre-Whitening (TFPW) approach was applied. The results of this study indicated that the ET0 trends for some cities were increasing (positive) however, for some sites, they showed decreasing (negative) trends. The most number of significant ET0 trends on a monthly time scale occurred at Birjand but no significant trend was observed at the Bandarabbas, Sabzevar and Semnan sites. On the annual time scale, Mashhad revealed the highest positive trend (7.5 mm per year). On the other hand, Esfahan showed the highest decreasing (negative) ET0 trend of about −6.38 mm per year. In general, the performances and abilities of the MK and SR tests were consistent at the verified significant level.