CAREER: The Influence of Desert Heat Lows on Monsoon Precipitation

这是一个学院早期职业发展(Career)项目，旨在支持一名初级教师发展和实施大气科学研究和教育的综合5年计划。研究构成部分审查了季风与通常位于极地一侧与季风区相邻的沙漠之间的联系(例如，撒哈拉沙漠位于萨赫勒地区的极地并与之毗邻)。PI以前的工作表明，包括萨赫勒、南亚和澳大利亚在内的几个季风区的降水变化与邻近极地沙漠上空云层以下的等效位温呈正相关。这种关系的一个假说是，沙漠热流产生浅层翻转环流，其中700mb层附近的流出具有向赤道方向的分量，通过在季风深对流区域对流层中部变暖和变干来减少季风降水。为了促进对这种季风-沙漠关系的理解，该奖项下的工作将解决三个主要问题：1)沙漠低热量中的浅层流动是否主要通过水分和干静态能量的水平平流来改变季风降水？2)低水平瞬变涡流在沙漠热低和季风之间的相互作用中有多重要？3)在西非、南亚和澳大利亚，热低与季风降水的相互作用方式是否基本相同？这些研究问题通过一个由三部分组成的研究议程来解决，其中的任务是：1)基于现场、卫星和再分析数据集的组合，描述在观测中发现的季风-沙漠关系；2)使用简单的理论模型探索这些关系；以及3)使用最先进的数值模型进行过程研究。这项职业计划的教育部分包括发展季风预报竞赛，有三个目标：1)促进关于天气、气候和相关基础科学的教育；2)加强招收和留住科学、技术、工程和数学(STEM)领域有远大抱负、代表性不足的高中生；以及3)创建一个传播和讨论季风预报和研究的国际社会。季风预报大赛通过一个网站举行，参赛者可以通过该网站输入西非、印度、澳大利亚和北美季风区的爆发日期和总季节性降雨量的预报。参与者被要求提交一个基本原理和他们的预测，该网站还包含关于季风的教育材料，以及对流的基本科学解释，从气压梯度产生风，以及其他相关主题。对预报员的指导，包括气候季风爆发日期和降雨量、厄尔尼诺的状态以及与业务产品的联系。作为预报竞赛的一部分，该项目寻求季风区居民作为预报员和博客作者的参与，以提供关于季风及其人类影响的现实世界视角。预报比赛还伴随着对纽黑文公立学校系统的教育推广工作。外展是通过科学合作实践学习和研究(SCHOLAR)项目进行的，在该项目中，学生们参加耶鲁大学为期三周的暑期住宿科学项目。PI正在与学者工作人员合作，开发一个关于天气、气候和季风的简短科学模块。此外，在该项目的最后三年，将挑选两名学生参加由国际和平协会部门组织的实地考察。

This is a Faculty Early Career Development (CAREER) project to support a junior faculty member in developing and conducting an integrated 5-year program of research and education in atmospheric science. The research component examines the connection between monsoons and the deserts typically found adjacent to monsoon regions on the poleward side (as, for instance, the Sahara is poleward of and adjacent to the Sahel). Previous work by the PI shows that variations in precipitation in several monsoon regions including the Sahel, South Asia, and Australia, are positively correlated with equivalent potential temperature below the cloud layer over adjacent poleward deserts. One hypothesis for this relationship is that desert heat lows produce shallow overturning circulations in which outflow near the 700mb level has an equatorward component which reduces monsoon precipitation by warming and drying the mid-troposphere over the region of monsoonal deep convection. To advance understanding of such monsoon-desert relationships, work under this award will address three main questions: 1) Does shallow flow in desert heat lows alter monsoon precipitation primarily through horizontal advection of moisture and dry static energy? 2) How important are low-level transient eddies in interactions between desert heat lows and monsoons? 3) Do heat lows interact with monsoon precipitation in fundamentally the same way in West Africa, South Asia, and Australia? These research questions are addressed through a three-part research agenda in which the tasks are 1) characterize the monsoon-desert relationships found in observations, based on a combination of in situ, satellite, and reanalysis datasets; 2) explore these relationships using a simple theoretical model; and 3) conduct process studies using a state-of-the-art numerical model.The educational component of this CAREER proposal involves the development of a monsoon forecasting contest with three goals: 1) fostering education on weather, climate, and relevant basic science; 2) enhancing recruitment and retention of high-promise, underrepresented high school students in science, technology, engineering, and math (STEM) fields; and 3) creating an international community for disseminating and discussing monsoon forecasts and research. The monsoon forecasting contest is held through a website which allows participants to enter forecasts of onset date and total seasonal precipitation for the monsoon regions of West Africa, India, Australia, and North America. Participants are asked to submit a rationale along with their predictions, and the website also contains educational materials on monsoons, along with basic science explanations for convection, generation of wind from pressure gradients, and other relevant topics. Guidance for forecasters, including climatological monsoon onset date and precipitation amount, the state of El Nino, and links to operational products. As part of the forecasting contest, the project seeks the participation of inhabitants of monsoon regions as forecasters and as bloggers, to provide a real-world perspective on monsoons and their human impacts. The forecasting contest is accompanied by an educational outreach effort to the New Haven Public School system. The outreach is conducted through the Science Collaborative Hands-On Learning And Research (SCHOLAR) program, in which students take part in a three-week residential summer science program at Yale. The PI is working with SCHOLAR staff to develop a short science module on weather, climate, and monsoons. In addition, in the last three years of the project, two students will be selected to attend a field trip organized by the PI's department.