Collaborative Research: Convection and Rainfall Enhancement over Mountainous Tropical Islands

热带岛屿的降雨量比附近的海洋地区要多。岛屿降雨的增加有多种原因，包括岛屿白天的加热和相关的海风引发雷暴，以及吹过山区岛屿的风。虽然岛屿降雨似乎是一个局部的研究课题，但对它的进一步了解有几个好处，可以跨越全球天气和气候的研究。例如，热带太平洋西部大岛屿（如婆罗洲、巴布亚新几内亚和苏门答腊岛）上的降雨在天气（几周）和气候（季节性）时间尺度上影响赤道太平洋盆地的风型。此外，对热带地区高雷暴的深入了解仍然是更好的天气预报和减少气候变化预测不确定性的主要障碍。与此相关的是，研究岛屿降雨可能有助于解决以下问题：湿润还是干燥的土壤更容易下雨，以及为什么会下雨；这些问题对于理解洪水和干旱的持续性非常重要。最后，了解岛屿降雨如何取决于附近海洋的温度仍然是一个挑战。这种对温度的依赖不仅对气候变化中极端降雨的社会影响很重要，而且还因为在所有陆地（尤其是热带岛屿）径流中发现的溶解矿物质可以在数百万年的时间里调节大气中的二氧化碳含量和全球温度。该项目的目标是通过使用大气的高分辨率数值模型模拟来研究岛屿降雨增强如何依赖于岛屿环境的多种因素，从而解决这些跨越天气、当前气候和过去气候的问题。这些因素包括附近海洋的温度、岛屿的湿度和高度、撞击岛屿的风的强度以及数值模式中模拟的区域的大小。这个研究项目将通过研究热带对流如何受到岛屿局部环境的影响，促进对调节气候的热带对流过程的认识。该研究项目支持一名研究生接受气候动力学方面的培训，并为从事学术或商业天气预报方面的教学和研究工作做准备，从而维持卓越气候研究所需的人力资源。将制作公开的教学录像，说明与岛屿雷暴和降雨有关的核心概念，包括海风和一天中雷暴触发的模式。一套用于分析高分辨率大气数值模型产生的输出的工具将提供给本科生、研究生和博士后研究人员。

More rain falls over tropical islands than nearby ocean areas. This enhancement of island rainfall occurs for multiple reasons, including triggering of thunderstorms by daytime heating of islands and associated sea breezes, as well as by winds blowing over mountainous islands. Although island rainfall may seem like a local subject of study, an improved understanding of it has several benefits that cut across study of global weather and climate. For example, rainfall over the large islands of the western Tropical Pacific (such as Borneo, Papua New Guinea, and Sumatra) influences wind patterns along the equatorial Pacific basin at both weather (a few weeks) and climate (seasonal) time scales. Also, a deeper understanding of tall thunderstorms in the tropics remains a major obstacle to better weather forecasts and reducing uncertainty in climate change projections. Connected with this, studying island rainfall may help address questions about whether it tends to rain more over wet or dry soils and why; these questions are important for understanding the persistence of floods and droughts. Finally, understanding how island rainfall depends on the temperature of the nearby ocean remains a challenge. This temperature-dependence is important not only for the societal impacts of rainfall extremes in a changing climate, but also because dissolved minerals found in the runoff from all land - but particularly tropical islands - can regulate atmospheric carbon dioxide content and global temperature over periods of millions of years. The goal of this project is to address these questions that cut across weather, current climate, and past climate, by using high-resolution numerical model simulations of the atmosphere to investigate how island rainfall enhancement depends on multiple factors of the island environment. These factors include the temperature of the nearby ocean, the wetness and height of the island, the strength of the winds impinging on the island, and the size of the region simulated in the numerical model. This research project will advance knowledge about the tropical convection processes that regulate the climate, by studying how tropical convections are influenced by local aspects of the island environment. The research project supports a graduate student who will gain training in climate dynamics and preparation for a career in teaching and research in academia or commercial weather prediction, thus sustaining the pool of human resources required for excellence in climate research. Publicly available instructional videos will be produced to illustrate central concepts associated with island thunderstorms and rainfall, including sea-breezes and the pattern of thunderstorm triggering over the day. A set of tools for analyzing the output generated by the high-resolution numerical model of the atmosphere will be made available to undergraduate students, graduate students, and postdoctoral researchers.