Figure 1. The mean hourly rainfall accumulation for each category (red for HiRH, green for MoRH and blue for LoRH. The square lines for HiWS, triangle lines for MoWS, and dot lines for LoWS). The WS is wind speed and the RH means moisture. Hi, Mo and Lo are hig, moderate and low, respectively.
研究表明，低层风场和湿度场显著影响了海南岛的降水：低层风速大小决定了降水的强度和空间分布，而湿度不仅影响白天降水的强弱，更决定了夜间能否形成降水(Fig. 1)。较小的风速引起下午在海岛上产生更强更广的低层风场辐合，从而造成更强的白天降水，这主要是由于来自不同方向的海风锋发展并传播至岛内碰撞引起(Fig. 2)。夜间降水只有在高湿度环境下才能形成，且风速越大，夜间降水越强，其与边界层的惯性震荡密切相关。此外，陆风与大尺度环境风的相互作用也对夜间降水有一定的影响。
Figure 2. Hourly rainfall accumulation (shaded; mm) and perturbation surface wind (vector; m s−1) for the horizontal wind every 2 hr from 11 to 17 LST in the afternoon. Each row represents for different wind categories (first for high wind (a‐d), second for moderate wind (e‐h), and third for low wind (i‐l)) under moderate moisture condition (MoRH).
本研究成果发表在国际期刊Geophysical Research Letters，文章第一作者是朱磊博士，通讯制作者是朱磊和宾州州立大学陈兴超教授（我院07级校友），该研究合作者包括实验室2019年开放课题负责人、中山大学白兰强博士，是双方通过开放课题合作取得的学术成果之一。
参考文献：
Zhu L, X. Chen and L. Bai, 2020: Relative Roles of Low-level Wind Speed and Moisture in the Diurnal Cycle of Rainfall over a Tropical Island under Monsoonal Flows, Geophys.Res.Lett., 47,e2020GL087467,https://doi.org/10.1029/2020GL087467.
Zhu L, Z. Meng, F. Zhang and P. M. Markowski, 2017: The influence of sea- and land-breeze circulations on the diurnal variability of precipitation over a tropical island. Atmos. Chem. Phys., 17, 13213–13232, 2017, https://doi.org/10.5194/acp-17-13213-2017.
