Discussion on other causes of drought in five provinces in southwest China

Recently, the meteorological drought in Yunnan Province has developed rapidly, and the drought is serious, which has caused serious agricultural disasters, and the meteorological grade of forest fire danger continues to be high. The occurrence and development of meteorological drought in Yunnan province has the characteristics of early appearance, long duration, wide influence and severe drought. The dry and wet seasons in Yunnan are distinct, and the distribution of precipitation in the four seasons is extremely uneven. Winter and spring 165438+ 10 to April of the following year is the dry season in Yunnan, and the precipitation accounts for only 0/0% to 20% of the annual/kloc-0, with frequent droughts in winter and spring. Especially since 2002, Yunnan has been under the climate background of less precipitation and higher temperature in summer and autumn, which also provides a dry and warm climate background for the occurrence of drought since autumn 2009. According to meteorologists, the main causes of meteorological drought in Yunnan are continuous low precipitation, high temperature, large evaporation of water vapor and early end of rainy season. The monitoring shows that from July 1 day to February 23, 2009, the average precipitation in Yunnan Province was 52 1.6 mm, which was 30% less than the multi-year average, breaking the record of average precipitation in the same period since June 1959. The average maximum temperature is 23.7℃, which is 2.0℃ higher than the average in the same period of many years, breaking the record of the average maximum temperature in the same period since 1959. From July to June, 2009, 65438+February, the average water vapor evaporation in Yunnan Province was 822.5 mm, which was higher than the average of the same period for many years 12%. From September 1 day in 2009 to February 23 this year, the average number of rainy days in Yunnan Province was 3 1 day, which was 44% less than the same period of many years, breaking the record of the minimum number of rainy days in the same period since 1959. Ask geography why it is snowy in the north and sunny in the south. At the beginning of 20 10, the violent cold wave and snowstorm, which have never happened in decades, hit most parts of northern China. At the same time, most parts of Yunnan are still sunny. Why is there such a huge contrast in the same season? What impact will the current climate in Yunnan have on production and life? How to deal with extreme weather conditions? With these questions, the reporter interviewed experts from Yunnan Meteorological Bureau. "Since June 2009, the abnormal atmospheric circulation caused by the unusually warm seawater in the equatorial Middle East Pacific Ocean has made it difficult for cold air to affect Yunnan southward. Coupled with the special geographical location of Yunnan's own low-latitude plateau, it led to continuous high temperature, little rain and dry weather last winter and this spring. " Liu Yu, national chief forecaster of Yunnan Meteorological Bureau, introduced. Extreme weather and climate events occur frequently, which increasingly affects the economic and social development of Yunnan. Among them, the abnormal weather caused by climate warming has a very prominent impact on the drought in Yunnan. Especially from July 1 day to June 20 10, 2009, the average precipitation in Yunnan Province was 29% less than the average for many years, which broke the record of the least precipitation in the same period since meteorological observation records. The average highest temperature in the province is 24.0℃, breaking the highest record since meteorological records. The average number of rainy days in the province is 65.9 days, breaking the lowest record since meteorological records. According to the monitoring of the "Meteorological Comprehensive Drought Monitoring, Early Warning and Impact Assessment" system of Yunnan Meteorological Observatory, as of 201010/0/2 1, except for 2 stations in Yunnan Province, all the remaining 123 stations have different degrees of drought, including 9/kloc-in the whole province. 73% of the stations reached the extreme drought level. According to the preliminary forecast of Yunnan Climate Center for the whole year of 20 10, although the temperature in winter last year was higher than normal, the staged cold air that affected Yunnan's winter was still active. Under the influence of warm cold air, severe low temperature and heavy frost are prone to occur, which causes great harm and loss to agriculture. Therefore, the meteorological department reminded all parts of Yunnan and relevant departments to do a good job in the cold and antifreeze work of spring sowing crops while doing a good job in drought resistance in the near future. Q: How often does global warming aggravate the drought in Yunnan? Yunnan is a transitional cross zone influenced by various monsoons (East Asian Monsoon, South Asian Monsoon and Plateau Monsoon), and it is a typical monsoon climate zone in China, with distinct dry and wet seasons. The monsoon climate forms the inevitability of drought in Yunnan, and the unstable monsoon activity causes the randomness of drought in Yunnan.