Tropical Gravity Waves and Latent Heating: Making the Invisible Visible

这项研究将联合使用重力波、降水和云观测，以及局地模式，以获得对流上升尺度潜热和波浪对环流的拖曳的新约束。对流云周围的重力波是复杂的、三维的、时变的现象。通过应用两个专门设计的区域模式工具，结合现有的观测，研究可以使潜热和波的不可见特征都可见。该项目的重点是将这一新知识应用于次网格尺度的重力波阻力问题，用于全球气候预测和天气预报。已被观测验证的重力波分解模型表明，从对流云发出的重力波的尺度和传播具有云内潜热局部快速变化的四维特性的特征。该小组将检验以下两个假设：(1)重力波和降水的观测限制了对流云内潜热的局部瞬时特性；热带重力波阻力是平流层低层风准两年振荡(QBO)的主要驱动力，它本身也是北半球冬季季节和年际气候可预报性和热带季节内和年际降水可预报性的主要因素。通过这一项目获得的重力波知识将清楚地描绘出重力波动量通量的变异性及其与对流云的关系，从而能够进行更准确的预测和未来的气候预测。这项研究将产生重大的科学和社会影响。这包括：(A)预报飞机感觉到的晴朗空气湍流；(B)对偏远海洋地区飓风加剧的预警；(C)提高热带天气预报技能；(D)非迁移性潮汐对中层大气层风的影响；(E)预报电离层扰动和通信频道中断。该项目将为早期职业科学家提供培训。该项目还将支持一名女性PI，她是STEM研究中代表性不足的小组的成员。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The research will involve a synergistic use of gravity wave, precipitation, and cloud observations together with local-area models for new constraints on convective updraft-scale latent heating and wave drag on circulation. Gravity waves surrounding convective clouds are complex, three-dimensional, time-varying phenomena. Through application of two specially designed regional model tools together with available observations, the research can make the invisible features of both the latent heating and the waves visible. The project focuses on applying this new knowledge to the problem of subgrid-scale gravity wave drag for global climate prediction and weather forecasting. Gravity wave resolving models that have been observationally validated indicate that the scales and propagation of gravity waves emitted from convective clouds carry the signature of the four-dimensional properties of the localized, rapid variations in latent heating inside the clouds.The team will examine the following two hypotheses: (1) Observations of gravity waves and precipitation constrain the local, instantaneous properties of latent heating inside convective clouds; and (2) Knowledge of the latent heating can be used to construct the missing features of the wave field needed to accurately assess their remote effects on circulation.Tropical gravity wave drag is the leading force driving the quasibiennial oscillation (QBO) in lower stratospheric winds, which itself is a leading factor in Northern Hemisphere wintertime seasonal and interannual climate predictability and tropical intraseasonal and interannual precipitation predictability. The knowledge of gravity waves gained from this project will provide a clear picture of the gravity wave momentum flux variability and relation to convective clouds, which will permit more accurate predictions and future climate projections.The research will have substantial scientific and societal impacts. These include: (a) forecasting clear air turbulence felt by aircraft; (b) early warning of hurricane intensification over remote ocean areas; (c) improving tropical weather forecast skill; (d) nonmigrating tidal influences on middle atmosphere winds; and (e) forecasting ionospheric disturbances and communication channel disruptions. The project will provide training to an early career scientist. The project would also support a female PI, a member of an under-represented group in STEM research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.