Spatial and temporal variability of precipitation concentration index, concentration degree and concentration period in Xinjiang, China

Abstract

This paper studied the spatial and temporal variability of the statistical structures of precipitation across Xinjiang, China, by analysing the time series of daily precipitation from 50 weather stations during the period from 1961 to 2008. Three indices precipitation concentration index (CI), precipitation concentration degree (PCD) and precipitation concentration period (PCP) were used to detect precipitation concentrations and the associated spatial patterns. The results show that higher precipitation CI values were mainly observed in Southern Xinjiang, whereas lower precipitation CI values were mostly detected in Northern Xinjiang. The precipitation CI values are noticeably larger in places where both annual total precipitation and number of rainy days are lower. The Mann-Kendall trend test demonstrates that the most parts of Xinjiang are characterized by no significant trends of precipitation CI at the 0.05 significance level. The periodicity characteristic of precipitation CI time series in Xinjiang could be detected by wavelet power spectrum analysis, and significant periods of that in most of Xinjiang were concentrated on 2-5 years band. The results of PCP reveal that rainfall in Xinjiang mostly occurs in summer, and the rainy season arrives earlier in Eastern Xinjiang than Western Xinjiang, whereas the results of PCD indicate that the rainfall in Northern Xinjiang was more dispersed within a year than that in Southern Xinjiang.

Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

“…We also used the precipitation concentration index (PCI) to evaluate the varying weight of monthly rainfall to the total amount of rainfall (Li et al 2010). By doing so, we will understand the monthly heterogeneity of rainfall amounts and its temporal trends.…”

“…Values above 20 correspond to climates with substantial monthly variability in rainfall amounts (Nel 2009 and references therein). A higher precipitation concentration index value also indicates that precipitation is more concentrated to a few rainy months during the year and vice versa (Li et al 2010;Zhaoetal.2011). Furthermore, the normalized precipitation anomaly series of annual rainfall (AR) and PCI are used to test for interannual rainfall variability.…”

Analysis of Rain Variability Using the Daily and Monthly Concentration Indexes in Southeastern Brazil

“…The study was conducted using meteorological data from the National Water The concentration index proposed by [1] was used to determine the relative impact of different precipitation classes, e.g., more intense precipitation observed in the heterogeneity of daily precipitation [32] [34] [39].…”

Risk assessment of precipitation extremes in northern Xinjiang, China

“…1) for the period from 1 January 1961 to 31 December 2010. This institution performed quality control of the dataset prior to its release, and homogeneous detection for the dataset was also done (Li et al 2011). In total, missing data accounts for 0.05% of the data series.…”

“…Li et al (2015) indicated that in China, there is less co-occurrence of consecutive wet and dry days, and more joint extreme heavy precipitation events with meteorological, public safety, and economical implications, involving less risk of flood and drought co-occurrence in the same year, but higher risk of floods. Li et al (2011) indicated that flood disasters have increased in response to the higher frequency of intense precipitation events and consequent amplification of their concentration indices and precipitation concentration. Zhang et al (2015) showed that indices representing temporal variations of regional heavy precipitation display strong inter-decadal variability, with limited evidence of long-term trends.…”