论文标题
表面风的昼夜周期和时间趋势
The diurnal cycle and temporal trends of surface winds
论文作者
论文摘要
风在气候系统中起着至关重要的作用。在这项研究中，我们分析了来自ERA5重新分析数据的表面昼夜周期的全球模式。我们发现，在土地上，尤其是在沙丘区域上，最大的风速和风向漂移电位（DP）发生在中午左右。但是，在海洋上，风在晚上也达到峰值。使用明智的热通量，我们表明，夜间陆上的风较弱是由于夜间冷却，使大气层水平及其与表面相关的强风 - 夜间冷却较小，在海洋上却小得多。我们还分析了来自美国400多个气象站的风数据，并发现与重新分析数据中类似的昼夜趋势。在过去的70年中，最大风速的时机（白天）的变化不大。然而，风速，风能和风向漂移电势随着海洋的时间而显着增加，并且在陆地和沙丘区域的程度较小。我们将ERA5的美国和欧洲DP与气象站的风速进行了比较，并发现ERA5显着低估了真正的风；但是，两者的时间模式相似。
Winds play an essential role in the climate system. In this study, we analyze the global pattern of the diurnal cycle of surface (10 m) winds from the ERA5 reanalysis data. We find that over the land and especially over sand dune regions, the maximal wind speed and wind drift potential (DP) occur during the hours around midday. However, over the ocean, the wind also peaks at night. Using the sensible heat flux, we show that the weaker winds over land at night are due to a nocturnal cooling that decouples upper atmospheric levels and their associated stronger winds from the surface -- nocturnal cooling is much smaller over the ocean. We also analyze wind data from more than 400 meteorological stations in the USA and find a similar diurnal trend as in the reanalysis data. The timing (during the day) of the maximum wind speed has not varied much over the past 70 years. Yet, the wind speed, wind power, and wind drift potential exhibit significant increases with time over the ocean and, to a much lesser degree, over the land and sand dune regions. We compare the USA and Europe DP and wind speed of the ERA5 to that of meteorological stations and find that the ERA5 significantly underestimates real winds; however, the temporal patterns of the two are similar.
