Climate Change Characteristics in Ecological Fragile Zones in China during 1980-2014

The climate change characteristics in ecological fragile zones in China since the 1980s were analyzed using a gridded monthly meteorological dataset. The results were as follows: (1) The annual and seasonal mean values for daily mean, maximum, and minimum temperatures have risen in most of the study areas. The increase in daily mean temperature is greater in the northern ecologically fragile zones than in the south. The increase in seasonal mean values for daily mean, maximum, and minimum temperatures in the northern areas and daily minimum temperature in southern areas was largest in spring and smallest in autumn or winter. (2) Annual and seasonal precipitation, averaged over the whole area, showed no clear trend. Precipitation anomaly percentage increased in spring and decreased in summer in most of the study areas. The annual, autumn, and winter anomalies mostly increased in the north but decreased in the south. (3) Relative humidity was mostly on the decline, with positive trends found only in autumn and winter in the southern part of the Loess Plateau and in winter in the ecologically fragile zones in the arid and semiarid areas, which also showed a large precipitation growth trend. (4) Wind speed decreased in most areas, with the largest downward trend occurring in spring. (5) Pan evaporation averaged over the whole area decreased in spring, summer, and annual amount, but it increased in winter. Seasonal and annual pan evaporation decreased in most areas of the northern ecologically fragile zones. Pan evaporation decreased in most areas of the southern ecologically fragile zones during spring and summer, while it increased during autumn, winter, and annual amount.