Climate warming can result in differences in precipitation distribution both at regional and global scales. In arid and semi-arid areas, precipitation is an important factor in the environment and can have a significant impact on ecosystem. Researches on precipitation and its variability in arid and semi-arid areas are of practical and theoretical significance to the sustainable development of environment.

Dr. XU Ligang et al. studied precipitation trends and variability from 1950 to 2000 in the arid lands of Central Asia (ALCA), which includes Kazakhstan, Uzbekistan, Turkmenistan, Kyrgyzstan, Tajikistan and the arid Northwest China. ALCA is one of the largest arid regions at the middle latitudes in the world and is likely to be strongly influenced by climate warming. Precipitation data from 344 meteorological stations in the ALCA were used in this study. Researchers selected run theory, extreme deviation theory, precipitation concentration index (PCI), Mann-Kendall rank correlation and climatic trend coefficient methods to analyze precipitation trends and variability in wet and dry years from 1950 to 2000 in the ALCA.

The longest dry period was larger than the longest wet period in the ALCA. The occurrence probability of a single year with less precipitation (40.0%) was lower than that of a single year with abundant precipitation (41.0%). The intensity of continuous drought in Kazakhstan, Turkmenistan and Tajikistan was weak, while it was strong in arid Northwest China, Kyrgyzstan and Uzbekistan. The values of precipitation concentration index (PCI) in the ALCA ranged from 12 to 36, indicating significant seasonal changes in precipitation. Precipitation in spring and winter accounted for 37.7% and 24.4% of the average annual precipitation, respectively.

Generally, annual precipitation in the ALCA displayed an increasing trend, with the rate of 3.9 mm/10a. Specifically, precipitation will increase in major Kazakhstan, Kyrgyzstan, Tajikistan and arid Northwest China, with rates of 2.6, 3.1, 3.7 and 1.8 mm/10a, respectively; while it will decrease in western Kazakhstan, with the rate of 1.96 mm/10a.

The result was published inJournal of Arid Land in August 2015.