Abstract

The spatial and temporal variations of some important near-surface climate parameters and extreme climate events in North China during 1961–2010 are analyzed by using 94 meteorological stations’ data in the study area. Results show that the annual mean surface air temperature in North China increased at the rate of 0.36°C per decade, higher than the national average in the same period. Increasing was particularly significant since the mid-1980s, with maximum increase in the middle and northeastern parts of Inner Mongolia. Increasing rate of the annual mean minimum temperature is much higher than that of the maximum temperature, which results in the decrease of the annual mean diurnal temperature range. Noticeable decrease is also observed in the frequency of cold wave. Annual precipitation shows a slight decreasing trend, with more pronounced decrease in southern Shanxi and eastern Hebei provinces, which is mainly represented as decreasing in contribution rates of rainstorm and heavy storm in flood-season (May to September). During 1961–2010, North China is characterized by a noticeable reduction in annual extreme precipitation, and an increase in high-temperature days over most parts, as well as more frequent droughts. There are remarkable reductions in annual sunshine duration and mean wind speed, associated with the most significant reduction of mean wind speed in midwestern and eastern parts of Inner Mongolia. Meanwhile, North China has experienced a noticeable decrease/increase in annual mean sanddust/haze days during the study period. However, there is no significant trend in fog days, except a pronounced decrease since the 1990s. Guo, W.-L., H.-B. Shi, J.-J. Ma, et al., 2013: Basic features of climate change in North China during 1961–2010. Adv. Clim. Change Res., 4 (2), doi: 10.3724/SP.J.1248.2013.073.

Abstract

Daily climate data at 110 stations during 1961–2010 were selected to examine the changing characteristics of climate factors and extreme climate events in South China. The annual mean surface air temperature has increased significantly by 0.16°C per decade, most notably in the Pearl River Delta and in winter. The increase rate of the annual extreme minimum temperature (0.48°C per decade) is over twice that of the annual extreme maximum temperature (0.20°C per decade), and the increase of the mean temperature is mainly the result of the increase of the extreme minimum temperature. The increase rate of high-temperature days (1.1 d per decade) is close to the decrease rate of low-temperature days (–1.3 d per decade). The rainfall has not shown any significant trend, but the number of rainy days has decreased and the rain intensity has increased. The regional mean sunshine duration has a significant decreasing trend of –40.9 h per decade, and the number of hazy days has a significant increasing trend of 6.3 d per decade. The decrease of sunshine duration is mainly caused by the increase of total cloud, not by the increase of hazy days in South China. Both the regional mean pan evaporation and mean wind speed have significant decreasing trends of –65.9 mm per decade and –0.11 m s−1 per decade, respectively. The decrease of both sunshine duration and mean wind speed plays an important role in the decrease of pan evaporation. The number of landing tropical cyclones has an insignificant decreasing trend of –0.6 per decade, but their intensities show a weak increasing trend. The formation location of tropical cyclones landing in South China has converged towards 10–19°N, and the landing position has shown a northward trend. The date of the first landfall tropical cyclone postpones 1.8 d per decade, and the date of the last landfall advances 3.6 d per decade, resulting in reduction of the typhoon season by 5.4 d per decade. Du, Y.-D., H. Ai, H.-L. Duan, et al., 2013: Changes in climate factors and extreme climate events in South China during 1961–2010. Adv. Clim. Change Res., 4 (1), doi: 10.3724/SP.J.1248.2013.001. The Working Group (WG) Reports and Synthesis Report of the IPCC Fifth Assessment Report (AR5) will be completed in 2013/2014. In order to address climate change, China Meteorological Administration (CMA) has launched climate change assessment reports since August 2008 for East China, South China, Central China, North China, Northeast China, Northwest China, Southwest China, and Xinjiang Uygur autonomous region. This is the first effort addressing climate change at a regional scale in China and among the first efforts globally. In order to ensure the quality of the report, CMA has organized hundreds of experts from CMA, colleges and universities, and the Chinese Academy of Sciences, and used a workflow similar to that of the IPCC AR5. The methods of field observation, data analysis, forecasting models and literature review have been used in these reports. Until now, eight regional assessment reports are being published. This journal will continuously publish the studies in three repeating sessions: climate change facts, impact assessment and adaptation, and mitigation, in order to provide the readers with this reference.

Abstract

The present study focused on statistical analysis of interannual, interdecadal variations of climate variables and extreme climate events during the period of 1961–2010 using observational data from 376 meteorological stations uniformly distributed across Southwest China, which includes Yunnan, Guizhou, Chongqing, Sichuan and Tibet. It was found that temperatures in most of the region were warming and this was especially evident for areas at high elevation. The warming was mostly attributable to the increase in annual mean minimum temperature. The characteristics of high temperature/heat waves are increase in frequency, prolonged duration, and weakened intensity. Annual precipitation showed a weak decreasing trend and drier in the east and more rainfall in the west. The precipitation amount in flood season was declining markedly in the whole region, rainfall from extreme heavy precipitation did not change much, and the portion of annual precipitation contributed by extreme heavy precipitation had an increasing trend, annual non-rainy days and the longest consecutive non-rainy days were both increasing, the extreme drought had a decreasing trend since the 1990s, the autumn-rain days displayed a downward fluctuation with apparent periodicity and intermittency. The number of southwestern vortices was decreasing whereas the number of moving vortices increased. Ma, Z.-F., J. Liu, S.-Q. Zhang, et al., 2013: Observed climate changes in Southwest China during 1961–2010. Adv. Clim. Change Res., 4 (1), doi: 10.3724/SP.J.1248.2013.030.