Recent recovery of surface wind speed in northwest China
Recent recovery of surface wind speed in northwest China
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DOI：
10.1002/joc.5679
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发表时间：
2018-07
期刊：
影响因子：
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通讯作者：
Yupeng Li;Yaning Chen;Zhi Li;G. Fang
中科院分区：
文献类型：
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作者：
Yupeng Li;Yaning Chen;Zhi Li;G. Fang
以前的研究报告称，北半球中纬度地区的大部分地面风速(SWS)已经下降。然而，很少有研究研究相对较新的风恢复现象。本文利用68个风场资料，对1969年至2015年中国西北地区的风速变化进行了分析。1992年，在经历了10年以0.036米S−1 a−1(p<；.05)的速度急剧下降后，SWS开始以0.004 m S−1 a−1的速度显著增加。这一增加的具体原因如下：(A)1992年以前减速期的SWS减少是由于春、夏季风速下降所致，而1992年后恢复期的风速增加是由于冬季风的增加所致。(二)风速变化较大的日数有所改变。具体而言，从1969年到1992年，S−1超过2米的天数均呈显著减少趋势，而从1993年到2015年，1-3米S−1的天数呈显著上升趋势。(C)位於1,000至1,500海里之间的车站海拔高度对气候变化的敏感度最高，在风速减缓(恢复)期间下降(增加)幅度最大。这些气象站可能会作为气候指标来预测未来的风速变化。中国西北部西南偏南既受大尺度大气环流变化的影响，又受区域变暖的影响。高低纬地区之间的地面气压梯度变化可能是非对称变暖下风速变化的重要因素。然而，城市化对SWS的趋势变化只起到了适度的作用。
Previous studies have reported that much of the surface wind speed (SWS) over the mid‐latitudes of the northern hemisphere has declined. However, very few studies have investigated the relatively recent phenomenon of wind recovery. Based on 68 wind data series, this paper examines changes in wind speed in northwest China between 1969 and 2015. In 1992, following a decade of sharply decreasing at a rate of 0.036 m s−1 a−1 (p < .05), the SWS began to significant increase at a rate of 0.004 m s−1 a−1. The specific reasons for this increase are as follows: (a) The decrease in SWS during the pre‐1992 slowdown period is the result of declining wind speeds in spring and summer, whereas increases in wind speed during the post‐1992 recovery period are caused by increased wind in winter. (b) The number of days featuring strongly varying wind speeds has changed. Specifically, the number of days above 2 m s−1 all show a significant decreasing trend from 1969 to 1992, whereas the number of days of 1–3 m s−1 shows a significant upward trend from 1993 to 2015. (c) Stations located between 1,000 and 1,500 m.a.s.l. (meter above sea level) are more sensitive to climate change than those at other altitudes, which shows the biggest decline (increase) trend during wind speed slowdown (recovery) period. These stations could potentially act as climatic indicators to predict future wind speed changes. SWS in northwest China have been affected by changes both in large‐scale atmospheric circulation and in regional warming. Surface pressure gradient variations between high‐ and low‐latitude regions may be important contributors to wind speed changes under asymmetric warming. However, urbanization is only moderately responsible for trend changes in SWS.