Continental scale surface air temperature variations: Experience derived from the Chinese region

Although there are still slight differences during some periods, the global surface air temperature (SAT) change series developed by different groups are generally very consistent with each other. However, there are still considerable uncertainties in the analysis of air temperature series at the regional scale. At the slightly larger sub-continental scale, to understand the trend and magnitude of regional climate warming in China, many teams of scientists have tried to establish a series of air temperature changes across the country from the 1880s onwards. However, until recently, the conclusions reached by these different teams remained markedly different, implying clear uncertainties. The reasons for the uncertainties are inhomogeneities in some SAT series, incomplete data and the biased nature of the station distribution. In addition, many studies have attributed the rapid warming rates in China to contributions from urbanization. However, additional research has shown that the characteristics of the periodic variations in temperature change across China in recent decades indicate that China has warmed faster than other areas at the same latitude and the average for the Northern Hemisphere. Although rapid urbanization in some parts of China has led to local-scale warming, due to the relatively small overall sizes of urbanized areas, the latest conclusions confirm that urbanization contributed less than 5% of the regional air temperature changes in China over the past century. Since approximately 1998, the general characteristics of air temperature changes in China have also shown warming, but more in extremes than average values. These phenomena can be explained by the physical mechanisms of atmospheric circulation changes. This paper discusses all these issues including summarizing the process and experience of establishing a series of air temperature changes at the sub-continental scale and estimating the magnitude of climate change by developing a series of regional temperature changes throughout the 20th century