100年来东亚和北非干旱半干旱区边界层高度的变化特征研究

Boundary Layer Height's Variation Characteristics Research of Arid and Semiarid Areas over East Asia and North Africa in Recent 100 Years

利用欧洲中心再分析资料ERA-20C、ERA-Interim和ERA40对1900—2015年东亚、北非干旱半干旱区边界层高度的年代际变化特征进行了研究。结果表明:(1)1900—2015年,东亚、北非干旱半干旱区边界层高度均值分别为755 m和834 m,东亚表现为显著的上升趋势,气候倾向率为2.0 m·(10a)-1,年代际震荡周期约为20年,北非表现为下降趋势,气候倾向率为-0.6 m·(10a)-1,年代际震荡周期约为40年。1964年和1940年分别为东亚、北非的显著转折年,1964年之后东亚边界层高度有明显抬升,1940年之后北非边界层高度震荡幅度明显增大。(2)东亚干旱半干旱区上升趋势最为明显的区域位于东部,气候倾向率为10.7~12.4 m·(10a)-1,其次位于中部,气候倾向率为3.8 m·(10a)-1;上升较缓慢的区域位于北部,气候倾向率为0.4~1.8 m·(10a)-1;塔克拉玛干沙漠呈下降趋势,气候倾向率为-1.2 m·(10a)-1。同时,在年代际波动中,东亚边界层高度在20世纪60—70年代呈现出剧烈的震荡也主要与中东部边界层高度的变化相关。(3)北非干旱半干旱区中北部表现为显著下降趋势,气候倾向率为-5.1^-1.4 m·(10a)-1;南部表现为上升趋势,气候倾向率为0.8~2.5 m·(10a)-1。然而,在年代际波动中,北非边界层高度在20世纪40年代之后震荡的加剧与南部边界层高度的变化密切相关。

Based on ERA-20 C,ERA-Interim and ERA40,the ECMWF＇s reanalysis data,the interdecadal variation characteristics of the boundary-layer height of arid and semiarid areas over East Asia and North Africa spanning from 1900 to 2015 was analysed. The results showed that：（ 1） From 1900 to 2015,the average boundary layer of Arid and Semiarid Areas of East Asia and North Africa were 755 m and 834 m,respectively. It presented significant upward trend over East Asia with the climate tendency rate of 2. 0 m ·（ 10 a）-1 and the decadal oscillation cycle of 20 years,and it presented downward trend over North Africa with the climate tendency rate of-0. 6 m ·（ 10 a）-1 and the decadal oscillation cycle of 40 years. The year 1964 and 1940 were the significant turning point of East Asia and North Africa,respectively. After 1964,the boundary layer height of East Asia had a apparent rise and the boundary layer height＇s oscillation amplitude of North Africa increased obviously after1940.（ 2） In arid and semiarid areas over East Asia,the most obvious upward trend region was at the east with the climate tendency rate of 10. 7 - 12. 4 m ·（ 10 a）-1,followed by central section,with the climate tendency rate of 3. 8 m ·（ 10 a）-1,and the slowly upward trend region was at the north,with the climate tendency rate of0. 4 - 1. 8 m ·（ 10 a）-1,the Taklamakan Desert showed downward trend with the climate tendency rate of-1. 2 m ·（ 10 a）-1. Meanwhile,in the decadal fluctuations,the severe concussion presented in the sixties and seventies of East Asia boundary layer height was mainly associated with the change of central and east regions.（ 3） In arid and semiarid areas over North Africa,the central and north regions showed significant downward trend with the climate tendency rate of-5. 1 --1. 48 m ·（ 10 a）-1,and the south region showed upward trend with the climate tendency rate of 0. 8 - 2. 5 m ·（ 10 a）-1. However,in the decadal fluctuations,the intensified concussion after the forties of North Africa boundary layer height was mainly associated with the change of south region.