Diurnal and semidiurnal variations of atmospheric pressure and surface winds are fundamental to the Earth‐Sun system. Past research in the tropical Pacific shows semidiurnal and diurnal patterns in the zonal and meridional wind anomalies, respectively. While the semidiurnal zonal wind pattern is consistent with atmospheric thermal tidal forcing, it is not yet certain what drives diurnal meridional wind variability. This study examines the diurnal cycle of meridional winds in the tropical Atlantic Ocean across four different seasons and the extent to which they impact the diurnal evolution of open‐ocean precipitation in boreal summer. Comparisons of direct observations from long‐term moored buoys to an atmospheric reanalysis (MERRA‐2) show that MERRA‐2 reproduces diurnal and semidiurnal pressure and wind variations. The MERRA‐2 atmospheric thermal tides are decomposed into migrating and nonmigrating tidal components, and the linear terms in the zonal and meridional momentum equations are calculated. There is an approximate balance between the acceleration and pressure gradient terms for the zonal migrating momentum budget in the open ocean, with larger residuals or imbalances between those terms for the other budgets. The meridional nonmigrating budget shows largest residuals near the African coastline, indicating that nonlinear processes like the evening initiation of convection are important over land. This evening convection drives the meridional component of surface convergence which is translated offshore by the nonmigrating tide in the form of gravity waves, potentially modified by the African Easterly Jet. During boreal summer, this convergence helps to induce a morning peak of precipitation over the open ocean.

中文翻译：

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热带大西洋大气热潮的表面表达及其对海洋降水的影响

大气压力和地表风的日变化和半日变化是Earth-Sun系统的基础。过去在热带太平洋地区的研究表明，纬向和经向风异常分别为半日和日模式。虽然半日的纬向风型与大气热潮强迫相一致，但尚不确定是什么驱动了日向子午风的变率。这项研究研究了热带大西洋上四个不同季节的子午风的日循环，以及它们在北方夏季对开放海洋降水的日演变的影响程度。从长期系泊浮标到大气再分析（MERRA-2）的直接观测结果的比较表明，MERRA-2再现了日和半日的压力和风的变化。MERRA-2大气潮汐被分解为迁移和非迁移潮汐分量，并计算了纬向和经向动量方程中的线性项。在远洋中，纬向迁移动量预算的加速度和压力梯度项之间有一个近似的平衡，其他预算中这些项之间存在较大的残差或不平衡。子午线非移民预算在非洲海岸线附近显示出最大的残留量，这表明对流的夜间启动等非线性过程在陆地上很重要。今晚的对流驱动表面会聚的子午线部分，该部分会由非迁移潮汐以重力波的形式在海上平移，并可能被非洲东风急流改变。在北方的夏天