What are the aspects of global climate change?

The climate change in China in recent years is mainly manifested in the obvious increase of surface average temperature, great interdecadal fluctuation of precipitation, obvious decrease of sunshine hours and near-surface average wind speed, and great spatial heterogeneity of extreme weather events, as follows:

(1) temperature change: the annual average surface temperature in China has increased significantly in recent 50 years, with the temperature rising range of 1.2℃ since 1960, and the warmest year has appeared in recent 20 years. The temperature rise is different in different regions. The general trend is that the temperature rise in the north is greater than that in the south, while the temperature rise in winter (average 0.04℃/ year) is obviously higher.

(2) Precipitation change: In recent 50 years, the annual precipitation change trend in China is not significant, with great interdecadal fluctuation, and there are obvious regional differences in precipitation trend. During the period of 1960-2006, the variation trend of annual precipitation in different regions has obvious spatial differences. The annual precipitation in the northwest, most areas in the middle and lower reaches of the Yangtze River, the western part of the southwest and the eastern part of South China shows an increasing trend, and the maximum average growth rate appears in the middle and lower reaches of the Yangtze River, while the annual precipitation in other areas shows a decreasing trend, among which the annual average precipitation in North China decreases the most.

(3) Changes of sunshine hours: In recent 50 years, the sunshine hours and the average wind speed near the ground in China have shown a significant decreasing trend. Among them, the sunshine hours in the whole country have generally decreased, especially in North China, with a decrease of 1 19 hours every 10 year; However, the decreasing trend in the middle and lower reaches of the Yangtze River and South China is 58-73 hours per 10 year, and 24 hours per 10 year in Northwest China. However, the decrease of wind speed is most obvious in the northwest.

(4) Changes of extreme weather events: In recent 50 years, the frequency of agro-meteorological disasters such as extreme high temperature and heat damage, sub-tropical extreme low temperature freezing damage, flood disaster and extreme drought in China has shown a significant increase trend, and the frequent occurrence of extreme weather and climate disasters has increased the inter-annual fluctuation of agricultural production. As far as regional changes are concerned, except for Central China, the frequency of high temperature and heat damage in other areas of China has increased significantly in summer, while the number of cold days in winter has decreased significantly. The flood disaster caused by rainstorm shows great spatial heterogeneity. These extreme events have increased in the northwest and the middle and lower reaches of the Yangtze River, but relatively few in the northeast and the northwest of the Yangtze River basin.

(Zhang Xuhui)