Surface Air Temperature Increases Overall in Central Asia from 1979 to 2011

The arid and semiarid region in central Asia includes Xinjiang in northwest China, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan. The region is especially sensitive and vulnerable to climate change. Rising air temperatures increase the surface evapotranspiration, stimulate substantial glacial retreats, and exacerbate water shortage in the region. So, it is crucial to understand its climate variation and change in order to support sustainable development policies.

To address the near-surface air temperature changes in central Asia from 1979 to 2011, HU Zengyun et al. first examined the accuracy of the three relatively high spatial resolution datasets (CFSR, ERA-Interim and MERRA) in describing the regional temperature variations in central Asia by comparing the reanalysis data with observations from meteorological stations in the region. Then, these evaluated datasets were used to examine temperature variations in central Asia for the period from 1979 to 2011.

The results suggested that the three reanalysis datasets match well with most of the local climate records, especially in the low-lying plain areas. The consensus of the multiple datasets showed significant regional surface air temperature increases of 0.36°C–0.42°C decade^-1 in the past 33 years. No significant contributions from declining irrigation and urbanization to temperature change were found. The rate is larger in recent years than in the early years in the study period.

Additionally, unlike in many regions in the world, the temperature in winter showed no increase in central Asia in the last three decades, a noticeable departure from the global trend in the 20th century. The largest increase in surface temperature was occurring in the spring season. Analyses further showed a warming center in the middle of the central Asian states and weakened temperature variability along the northwest–southeast temperature gradient from the northern Kazakhstan to southern Xinjiang.

The reanalysis datasets also showed significant negative correlations between temperature increase rate and elevation in this complex terrain region. The study was published in Journal of Climate in February 2014.