近55年来青海省海东市气候变化特征及影响因子分析

Analysis of climate change characteristics and influence factors inHaidong of Qinghai Province in recent 55 years

利用青海省海东市5个气象台站1961-2015年气候资料,采用线性回归和Mann-Kendall突变检测等方法,对海东市近55年的年和季平均气温、降水量、日照时数、风速、沙尘日数、云量和相对湿度等气候要素以及降水日数、潜在蒸散量和湿润指数的变化趋势和变化特征进行了研究,结果表明:(1)近55年海东市随着气候变暖降水减少(减少速率-4.9 mm·(10a)^-1 ),总体呈现不明显的“暖干化”趋势。年平均气温和潜在蒸散量呈现显著的上升趋势(上升速率0.33℃·(10a)^-1 和7.9 mm·(10a)^-1 ),年降水日数、平均风速、沙尘暴日数、日照时数、云量和相对湿度表现为显著减少趋势(减少速率分别为-2.3 d·(10a)^-1 、-0.13 m·s -1 ·(10a)^-1 、-6.3 d·(10a)^-1 、-36.6 h·(10a)^-1 、-0.12成·(10a)^-1 和-0.7%·(10a)^-1 ),湿润指数和降水量表现为不显著的减少趋势。(2)海东市年平均气温和潜在蒸散量分别在1995-1996年和2001年发生了显著的突变性升高,年平均风速、降水日数、日照时数、总云量和相对湿度分别于1982年、1993-1994年、2002-2003年、1984年、2009-2010年呈显著突变性减小,降水量和湿润指数的变化未达到突变标准。(3)海东市冬季气温变化与青藏高原指数、北极涛动指数和西风环流指数有明显的正相关关系,青藏高原的动力和热力作用对高原东北侧的海东市气温变化有很重要的影响,而该地区温度还受由北极涛动引起的冬季风和西风环流的影响。海东市夏季降水量与南亚夏季风指数和北极涛动指数有较好的负相关,南亚夏季风的进退以及所携带的水汽是影响该区域降水量变化的主要因素之一。

Using climatic data of 1961-2015 from 5 meteorological stations in Haidong, Qinghai Province, and the method of linear regression and Mann-Kendall mutation detection, the climatic factors such as average annual and seasonal temperatures, precipitation, sunlight hours, wind speed, dust day, cloud, and relative humidity, as well as the change trend and change characteristic of the raining days, potential evapotranspiration, and humidity index were studied.The result showed:(1) In recent 55 years, Haidong had been warmer with the decrease of precipitation(-4.9 mm·(10a)^-1 ), showing an obvious ‘warmer and dryer’ trend.The annual average temperature and potential evapotranspiration showed a significant increase trend (0.33 ℃·(10a)^-1 and 7.9 mm·(10a)^-1 ), the number of annual precipitation days, the average wind speed, the number of sandstorm days, sunshine hours, cloud and relative humidity showed a significant decrease trend(-2.3 d·(10a)^-1 ,-0.13 m·s -1 ·(10a)^-1 ,-6.3 d·(10a)^-1 ,-36.6 h·(10a)^-1 ,-0.12·(10a)^-1 and -0.7%·(10a)^-1 ), the humidity index and precipitation showed decreased trend but not significant.(2) The average annual temperature and potential evapotranspiration had a significant abrupt increase in 1995-1996 and 2001.The average annual wind speed, the number precipitation days, the sunshine hours, the total cloud and relative humidity significantly lower in 1982, 1993-1994, 2002-2003, 1984 and 2009-2010, while the change of the humidity index did not reach the mutation standard.(3) There was a significant positive correlation between the winter temperature change in Haidong and the Qinghai Tibet Plateau index, the Arctic Oscillation Index and the westerly circulation index.The dynamic and thermodynamic effects of the Qinghai Tibet Plateau had an important influence on the temperature changes in Haidong, which was located in the northeast side of plateau, and the temperature in this area was also affected by the winter wind and the westerly circulation caused by the Arctic Oscillation.The summer precipitation in Haidong had a greater negative correlation with the south Asian summer monsoon index and the Arctic Oscillation Index.The advance and retreat of the south Asian summer monsoon and its water vapor were one of the main factors affecting the precipitation in study area.