Precipitation In Xinjiang Research Articles

Temporal and Spatial Variation in Regional Climate and its Impact on Runoff in Xinjiang, China

Based on the meteorological and surface runoff data from Xinjiang for the past 50 years, this study examined the temporal-spatial variation characteristics of the air temperature, precipitation and runoff in Xinjiang using nonparametric tests and wavelet analysis. The results indicate that the air temperature declined slightly in Kuche (KC). There were slight increasing trends in Bayinbluk (BYBLK), Alar (ALR) and Yutian (YT). The rest of the meteorological stations all had significant increasing trends. The precipitation showed significant increasing trends in the Altai Mountains, Alashankou (ALSK) and Jinghe (JH) in northern Xinjiang and a slight decreasing trend in Tuoli (TL). The other stations showed slight increasing trends. The annual rate of change of precipitation was greater in the northern mountain area than in the southern plains area. In the Tianshan Mountains, the decreasing trend of precipitation at BYBLK was not statistically significant, while the precipitation in the other stations increased to the high-precipitation areas from two low-precipitation centers, Zhaosu (ZS) and BYBLK. In the Tarim Basin of southern Xinjiang, the increasing trend and increasing rate of precipitation were more significant on the northern margin than they were on the southern margin. With regard to the surface runoff, significant uptrends appeared in Kenswat (KSWT), Dashankou (DSK), Shiliguilank (SLGLK), Xiehela (XHL) and Yzmeilek (YZMLK). Kaqun (KQ) and Wuluwat (WLWT) had slight increases, and Tongguzlek (TGZLK) showed a slight downtrend. The variations in air temperature and precipitation in Xinjiang had significant periods of 4–9 years and 3–10 years, respectively. The periods for the annual runoff were 5–9 years.

Spatial and temporal trends of climate change in Xinjiang, China

Temperature and precipitation time series datasets from 1961 to 2005 at 65 meteorological stations were used to reveal the spatial and temporal trends of climate change in Xinjiang, China. Annual and seasonal mean air temperature and total precipitation were analyzed using Mann-Kendall (MK) test, inverse distance weighted (IDW) interpolation, and R/S methods. The results indicate that: (1) both temperature and precipitation increased in the past 45 years, but the increase in temperature is more obvious than that of precipitation; (2) for temperature increase, the higher the latitude and the higher the elevation the faster the increase, though the latitude has greater influence on the increase. Northern Xinjiang shows a faster warming than southern Xinjiang, especially in summer; (3) increase of precipitation occurs mainly in winter in northern Xinjiang and in summer in southern Xinjiang. Ili, which has the most precipitation in Xinjiang, shows a weak increase of precipitation; (4) although both temperature and precipitation increased in general, the increase is different inside Xinjiang; (5) Hurst index (H) analysis indicates that climate change will continue the current trends.

Response of vegetation to temperature and precipitation in Xinjiang during the period of 1998-2009

In this paper, 10-day spatio-temporal response of vegetation to the change of temperature and precipitation in spring, summer, autumn and whole year during the period of 1998―2009 was analyzed based on the data of SPOT VEGETATION-NDVI and 10-day average temperature or precipitation from 54 meteorological stations in Xinjiang. The results show that the response of 10-day NDVI to temperature was more significant than that to precipitation, and the maximal response of vegetation to temperature and precipitation lagged for two 10-day periods. Seasonally, the effect of temperature and precipitation on vegetation NDVI was most marked in autumn, then in spring, and it was not significant in summer. The response of vegetation to 10-day change of meteorological factors was positive with a long affecting duration in spring, and it had a relatively short affecting duration in autumn and summer. Spatially, the 10-day maximal response of NDVI to temperature in northern Xinjiang was higher than that in southern Xinjiang. The correlation between the 10-day NDVI in whole year and the temperature in the 0-8 10-day period was significantly higher than that between the annual NDVI and the annual temperature at all meteorological stations; the interannual change of NDVI was accordant well with the change of annual precipitation. However, the effect of precipitation within a year on NDVI was not strong. The results indicated that interannual change of temperature was not the dominant factor affecting the change of vegetation NDVI in Xinjiang, but the decrease of annual precipitation was the main factor resulting in the fluctuation of vegetation coverage. Ten-day average temperature was an important factor to promote vegetation growth in Xinjiang within a year, but the effect of precipitation on vegetation growth within a year was not strong.

Magnification of Flood Disasters and its Relation to Regional Precipitation and Local Human Activities since the 1980s in Xinjiang, Northwestern China

Analyses of flood disasters were conducted using 1950–2001 data on the flood-damaged areas of cropland, the annual number of flood disasters and the direct economic losses in Xinjiang. There is an increasing trend in flood disasters in Xinjiang during the second half of the 20th century, especially since the mid-1980s. Results of a non-parametric Mann–Kendall test on the cropland-flooded index time series revealed an abrupt change in the mid-1980s. The reasons are discussed with respect to changes in annual precipitation and regional human activities, by correlating cropland-flooded area to annual precipitation and three socio-economic parameters (population, cropland area and GDP). The correlation coefficients between the flood-damaged area and the annual precipitation during the periods 1961–1998 and 1987–1998 were substantially higher than during the period of 1961–1986. The correlation coefficients between the flood-damaged area and the three human activity parameters, however, were relatively high for the whole period of 1961–1998, but generally not significant for the 1961–1986 and 1987–1998 periods, separately. These suggest that the occurrence of flood disasters could be mainly induced by local human activities before the mid-1980s, and thereafter mainly by abnormal precipitation in Xinjiang. Meteorological and hydrological records showed that the number of heavy rainfall events and the frequency of rainstorm flood disasters increased since the 1980s. In addition, siltation of reservoirs and loss of flood control structures are partly responsible for the increase of flood-damaged area. These results suggest that the increasing trend in flood disasters in Xinjiang since the middle 1980s could be attributed, at least in part, to an increasing trend in annual precipitation.