1973—2010年毛里塔尼亚气候变化与风况特征

Climate Change and Wind Regime in Mauritania from 1973 to 2010

利用1973—2010年12个站点的年平均气温、降水量、风向、风速数据,对38a来毛里塔尼亚气候变化和风况特征作了初步分析。结果表明:毛里塔尼亚沿海区域38a来呈变暖趋势,北部荒漠区域和南部热带草原区域则呈现冷暖交替变化的趋势。20世纪60年代降雨量最多,70年代和80年代降雨量偏少,总体上降雨量略有减少。除沿海区域外,南部热带草原区域和北部荒漠区域少雨期和降温期相对应,多雨期与升温期相对应,降雨滞后于温度。1973—2010年月平均风速均呈现下降趋势,南部热带草原区域下降趋势较为明显,北部荒漠区域下降趋势不明显。月平均风速为春季、夏季较大,冬季次之,秋季最小。季节风热条件存在明显差异,北部风热同步,南部先同步后异步,沿海则完全不同步。各站点的年风向频率,沿海区域以北风为主,而北部荒漠区域及南部热带草原区域风向则介于东、北向之间。

Based on statistics and calculations of air temperature,precipitation,wind speed and wind direction data from12 weather stations,which are divided into three zones in Mauritania from1973 to 2010,this paper studied climate change and wind regime features,and drawn some preliminary conclusions as follows:(1)The air temperature showed an increasing trend in coastal zone while an alternation of cold and warm in northern desert zone and southern savanna zone during the 38 years.(2)The precipitation exhibited a decreasing trend in general in Mauritania.The most pluvial period is 1960 s,and rainless periods are 1970 s and 1980 s.Excepted for coastal zone,dry periods correspond with cooling phases,and pluvial periods correspond with heating phase.Influenced by monsoon climate,the change between precipitation and temperature is out of sync,rainfall has a bit lag with temperature variations.(3)The monthly average wind speed showed a decreasing trend in Mauritania from1973 to 2010.Through the comparative analysis,difference relationship had been found between wind speed and air temperature variations in three zones.Excluding coastal zone,there existed a phenomenon called as'wind-temperature synchronization'in all seasons in northern desert zone and the spring and summer of southern savanna zone.Affected by Atlantic trade winds and Harmattan wind,the main wind direction showed a seasonal variation,but through the analysis of annual wind direction frequency,three zones were all dominated by north or northeast wind.