Analysis Of Characteristics Of Low-temperature Disaster Under Climate Change

In recent years, climate change caused by the changing climate factors had a significant impact on agricultural production in China. It is of great importance to do some research on climate change in China, and investigate in the changing features of the low temperature disasters under climate change, in order to provide some advices for agriculture adapting to climate change in China.In this study, precipitation and temperature were taken as the main research factors, the changing features of climate were analyzed through calculating the overall trend and the decadal trends of the climate factors in 1965-2014. It was more focused on the spatial and temporal deficiencies of climate change. The characteristics of low temperature disaster and its relationship with the change of temperature and growth period were discussed through the comprehensive analysis of the changes of temperature, growth period and low temperature disasters in 1992-2011.The main conclusions are as follows:(1) In the past 50 years, it showed an overall warming trend in China. The warming trend was weak in southern China, well in northern China the trend was strong, In the more warming areas, the elevated level in lowest temperature was generally higher than that of the average temperature and the highest temperature. As for the precipitation, there was an obvious increase in East China, while there was a decrease in Southwest and North China. There were big regional differences among the precipitation variation in Northeast China and central China, however, the precipitation variation in Northwest China was not so large, and it shows an increase trend in general.(2) In the past 50 years, there were some differences in the linear trend in temperature in different months. In October to February, there was a constant warming trend in China; from March to September, there were some regions that showed obvious decreasing trend in temperature, in which Central China showed more months and degrees in the temperature decrease. The temperature fluctuations weakened in the winter half year in general, but there was an increasing in the strong fluctuation areas in the summer half year. The decrease of the lowest temperature fluctuation was most obvious, and the precipitation variation mainly occurred in April to October. The precipitation reduction in June and August contributed most to the Southwest China. The precipitation reduction mainly occurred in July to August. East China has the biggest difference in precipitation variation in different months, the more increased months were January, March, July and August, and the most decreased months were April, May and September.(3) In the past 50 years, the Northeast China and North China has the fastest increase in temperature in the third ten years(1985-1994), while South China, central China, Southwest, southwestern part of the Northwest China go through the fastest warming in the fourth ten years(1995-2004). In 1975-1984, there was a cooling trend in North China, Central China, East China and other places, while in 2005-2014 years, most of the stations in China showed a cooling trend, in which the Northeast China, North China, Northwest China became the most obvious cooling regions. As for precipitation, the precipitation variation of the continental climate regions in Northwest China was relatively small, and it maintained the trend of weak increase in the 50 years. In Southwest China and North China, the precipitation kept decreasing. Northeast, the Southeastern part of South China, the northern part of Central China and the coastal areas of North China kept decreasing in precipitation in recent twenty years.(4) In 1992-2011, there was an overall reduction of frost disasters in China, in which East China decreased the most, however, the Northwest China and South China were the main areas that frost disasters increased. The chilling disaster increased in general, there was the most significant increase in the chilling injure, there was an increase in chilling damage in South China, and there was a decrease in chilling injure in Central China.(5) In 1992-2011,the cooling trends in July in Northeast China, December to January in South China were the reason of the increase of low temperature disaster.(6) In Northwest China the higher temperature didn’t took an decrease to frost, because the date of winter wheat’ growing stage deferred. Frost in East China decreased in January while temperature dropped reason in winter wheat’ stop growing date advanced and rape’s bolted stage date defered.