全球地表静化

全球地表静化 (英文：Global terrestrial stilling) ，指 1980 年到 2010 年期间，在地球的地表附近观测到的风速下降。Roderick ML, Rotstayn LD, Farquhar GD, Hobbins MT (2007) On the attribution of changing pan evaporation. Geophys Res Lett 34(17): L17403. 近地面风速下降主要影响南北半球的中纬度地区。全球平均风速以 -0.140 m/s•dec−1 的速度递减 (即每10年下降0.1米每秒的风速)，过去五十年间下降幅度达5%至15%。McVicar TR, Roderick ML, Donohue RJ, Li LT, Van Niel TG, Thomas A, Grieser J, Jhajharia D, Himri Y, Mahowald NM, Mescherskaya AV, Kruger AC, Rehman S, Dinpashoh Y (2012) Global review and synthesis of trends in observed terrestrial near-surface wind speeds: Implications for evaporation. J Hydrol 416–417: 182–205. 高纬度地区 (纬度> 75°) 则呈现风速上升趋势。 与陆地表面观测到的风力减弱相反，海洋区域的风力呈现增强趋势。Wentz FJ, Ricciardulli L, Hilburn K, Mears C (2007) How much more rain will global warming bring? Science 317(5835): 233–235. Young IR, Zieger S, Babanin AV (2011) Global trends in wind speed and wave height. Science 332(6028): 451–455. . 然而，自 2010 年前后开始，风速的下降趋势在部分区域出现了逆转。

地表静化的真正原因尚无定论，其主要的因素有两个：

 大气环流在较大尺度上的变化。
 因为森林生长、 土地利用变化及城市化等因素导致的地表粗糙度增加。

由于气候变化，地表静化目前已成为社会关注的潜在问题，因为它不仅会影响到风力发电、农业、水文和生态环境，还与灾害、空气质量和人类健康等众多领域密切相关。

 原因 
地表静化的原因尚无定论。它可能是由于多种因素同时相互作用，且这些因素可能随空间和时间而变化。

科学家指出，影响风速减缓的主要原因包括：

 地表粗糙度增加（如森林生长、土地利用变化和城市化）。在气象站附近，类似风速计的测量仪器会增强空气流动时遇到的摩擦力，从而导致低层风速进一步减弱。 Vautard R, Cattiaux J, Yiou P, Thépaut JN, Ciais P (2010) Northern Hemisphere atmospheric stilling partly attributed to an increase in surface roughness. Nat Geosci 3(11): 756–761.  Bichet A, Wild M, Folini D, Schär C (2012) Causes for decadal variations of wind speed over land: Sensitivity studies with a global climate model. Geophys Res Lett 39(11): L11701.  Wever N (2012) Quantifying trends in surface roughness and the effect on surface wind speed observations. J Geophys Res – Atmos 117(D11): D11104. .
 大气环流在较大尺度上的变化。例如哈德利环流向极地扩张Lu, J., G. A. Vecchi, and T. Reichler, 2007: Expansion of the Hadley cell under global warming. Geophys. Res. Lett., 34, L06805, . ，以及主导近地面风速变化的反气旋和气旋的漂移。 Lu J, Vecchi GA, Reichler T (2007) Expansion of the Hadley cell under global warning. Geophys Res Lett 34(6): L06805. . Azorin-Molina C, Vicente-Serrano SM, McVicar TR, Jerez S, Sanchez-Lorenzo A, López-Moreno JI, Revuelto J, Trigo RM, Lopez-Bustins JA, Espirito-Santo F (2014) Homogenization and assessment of observed near-surface wind speed trends over Spain and Portugal, 1961–2011. J Climate 27 (10): 3692–3712.  Azorin-Molina C, Guijarro JA, McVicar TR, Vicente-Serrano SM, Chen D, Jerez S, Espirito-Santo F (2016) Trends of daily peak wind gusts in Spain and Portugal, 1961–2014. J Geophys Res – Atmos 121(3): 1059–1078. 
 风速测量方法的变化。比如风速计设备的老化和误差、风速计的技术改进、风速计高度的变化 Wan, H., L. W. Xiaolan, and V. R. Swail, 2010: Homogenization and trend analysis of Canadian near-surface wind speeds. J. Climate, 23, 1209–1225, .、测量地点的转移、监测站周围环境的变化、仪器校准时的问题、以及测量时间间隔。 Azorin-Molina C, Vicente-Serrano SM, McVicar TR, Revuelto J, Jerez S, Lopez-Moreno JI (2017) Assessing the impact of measuring time interval when calculating wind speed means and trends under the stilling phenomenon. Int J Climatol 37(1): 480–492. 
 “全球暗化”，由于气溶胶和温室气体浓度增加，使得到达地球表面的太阳辐射量减少，大气趋于稳定，导致风力减弱，地表静化。 Xu M, Chang CP, Fu C, Qi Y, Robock A, Robinson D, Zhang H (2006) Steady decline of East Asian monsoon winds, 1969–2000: evidence from direct ground measurements of wind speed. J Geophys Res-Atmos 111: D24111. 
 影响 
地表静化现象的影响具有重要的科学、社会经济及环境意义，涉及大气与海洋动力学及诸多相关领域，包括：

 可再生风能Otero C, Manchado C, Arias R, Bruschi VM, Gómez-Jáuregui V, Cendrero A (2012), Wind energy development in Cantabria, Spain. Methodological approach, environmental, technological and social issues, Renewable Energy, 40(1), 137–149, 
 农业和水文McVicar TR, Roderick ML, Donohue RJ, Van Niel TG (2012), Less bluster ahead? Ecohydrological implications of global trends of terrestrial near-surface wind speeds, Ecohydrol., 5(4), 381–388, 
 风媒植物物种的迁移 Thompson, S.E., and G.G. Katul (2013), Implications of nonrandom seed abscission and global stilling for migration of wind-dispersed plant species, Glob. Chang. Biol., 19(6):1720–35, . 
 与风有关的自然灾害 Kim J, Paik K (2015) Recent recovery of surface wind speed after decadal decrease: a focus on South Korea. Clim Dyn 45(5): 1699–1712.  
 风暴潮，海浪对海洋和沿海地区的影响 Cid A., M. Menendez, S. Castanedo, A.J. Abascal, F.J. Méndez, and R. Medina (2016), Long-term changes in the frequency, intensity and duration of extreme storm surge events in southern Europe, Clim. Dyn., 46(5), 1503–1516, 
 空气污染物的扩散 Cuevas, E., Y. Gonzalez, S. Rodriguez, J.C. Guerra, A.J. Gomez-Pelaez, S. Alonso-Perez, J. Bustos, and C. Milford (2013), Assessment of atmospheric processes driving ozone variations in the subtropical North Atlantic free troposphere, Atmos. Chem. Phys., 13(4), 1973–1998, .

Category:气候变化
然而，就风能而言，近地表风速观测主要集中在离地 10 米范围内，而风力涡轮机通常位于地表以上 60 至 80 米处，因此该领域仍需更多研究。还需在高海拔地区开展更多研究，这些地区通常被称为"水塔"，是世界淡水供应的主要来源地。 Viviroli D, Archer DR, Buytaert W, Fowler HJ, Greenwood GB, Hamlet AF, Huang Y, Koboltschnig G, Litaor MI, Lopez-Moreno JI, Lorentz S, Schadler B, Schreier H, Schwaiger K, Vuille M, Woods R. 2011. Climate change and mountain water resources: overview and recommendations for research, management and policy. Hydrology and Earth System Sciences 15(2): 471–504. . Viviroli D, Durr HH, Messerli B, Meybeck M, Weingartner R. 2007. Mountains of the world, water towers for humanity: typology, mapping, and global significance. Water Resources Research 43(7):W07447. .研究表明，高海拔地区的风速下降速度比低海拔地区记录的变化更为显著 McVicar TR, Van Niel TG, Roderick ML, Li LT, Mo XG, Zimmermann NE, Schmatz DR (2010). Observational evidence from two mountainous regions that near-surface wind speeds are declining more rapidly at higher elevations than lower elevations: 1960–2006. Geophys Res Lett 37 (6): L06402. 而且，已有几篇中国论文证明了青藏高原的这一情况。 You, Q., Fraedrich, K., Min, J., Kang, S., Zhu, X., Pepin, N., Zhang, L. (2014) Observed surface wind speed in the Tibetan Plateau since 1980 and its physical causes. International Journal of Climatology 34(6), 1873–1882. 

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