我国西南地区风速变化及其影响因素

基于110个台站日风速观测资料,对我国西南地区1969—2009年风速时空变化及其影响因素进行研究,结果表明:1969—2009年西南地区平均风速以0.24 m s-110a-1的速率显著降低,其中1969—2000年平均风速以0.37 m s-110a-1速率降低,而2001—2009年却以0.55 m s-110a-1的速率升高,各季节、非季风和季风期风速变化趋势与年序列相似。空间分布上,1969—2009年风速降低台站主要位于高海拔区,降低幅度呈现西高东低趋势。1969—2000年风速降低台站主要位于西藏高原、横断山区和云南高原。2001—2009年风速增加台站主要位于云南高原、横断山区和四川盆地。风速这种变化趋势一方面受大气环流影响,西风环流和季风环流风速的减弱可能是2000年之前风速降低的重要原因,而纬向风的加强则对2000年以来风速增强有重要贡献。另一方面,区域变暖是风速降低的关键诱因。

Wind speed changes and its influencing factors in Southwestern China

Based on the daily wind speed observation data of 110 stations,this paper studies in temporal changes of wind speed and its influencing factors in Southwest China from 1969 to 2009. The results show that there was a statistically significant decrease of 0.24 m s^-1 10a^-1 in the annual mean wind speed in Southwestern China from 1969 to 2009. The annual average wind speed of 0.37 m s^-1 10a^-1 rate decreased from 1969 to 2000,while the wind speed increased of 0.55 m s^-1 10a^-1 from 2001 to 2009. The pattern of seasonal changes of wind speed was similar. From 1969 to 2009,there was a significant reduced in wind speed,the wind speed decreased from 1969 to 2000,while the wind speed increased from 2001 to 2009. On the spatial distribution of it,from 1969 to 2009 the annual wind speed reducing stations were mainly located in high altitude area,reducing the magnitude of the performance gradually decreasing from west to east,reflecting the impact of the terrain. From 1969 to 2000,the wind speed reducing stations were mainly located in the Tibetan Plateau,Hengduan Mountains and the Yunnan Plateau,the wind speed increases stations were located in Guizhou Plateau and the Sichuan Basin. From 2001 to 2009,the wind speed increases stations were mainly located in Yunnan Plateau,Hengduan Mountains and the Sichuan Basin,reducing wind stations were mainly located in the Tibetan Plateau and Guizhou Plateau. On the one hand,the analysis have confirmed that the decreasing wind speed was caused mainly by the decreasing monsoon circulation and Westerlies from 1969 to 2000,and the strengthening latitudinal wind speed has made some contributions on the increasing wind speed after 2000. And what's more,the strengthening Tibetan monsoon has also made some contributions to wind change. On the other hand,regional warming was the key incentive for wind decreased. Warming temperatures rose,especially the lowest temperature significantly warming was the main reason that results in the decrease of wind speed,and further analysis revealed that weaken of the pressure gradient between the different latitudes is the key factor of reducing the wind speed.