Lake Breeze System of the Great Salt Lake

浅层热驱动风环流通常沿沿着广泛的海岸线发展，在这些海岸线上，太阳能吸收、蒸发和由此产生的感热率的水平梯度往往相当大。相关的海风发展沿着广泛的（一般是固定的）海岸线接壤的平坦地形已被很好地描述。这些环流调节表面空气温度和边界层混合，从而影响沿海地区的气象和空气质量。不太清楚的是，在陡峭的地形和/或可变的海岸线位置的存在下，湖风形成的结构和动力学，因为很容易发生，由于在干旱地区的径流湖泊水位波动。这就是大盐湖的情况，它与湖城的主要市区接壤，在过去十年中，水位和海岸线的相关投影发生了显著变化。先前的工作已经描述了GSL湖风形成的雏形，包括其频率和首选的季节性统计，但主要局限于二维（基于表面）的角度来看。这项新的研究将（1）分析10年来的存档观测数据，其中包括来自相对密集的表面mesonetwork的数据（“MesoWest”及其前身"犹他州Mesonet“）和一个终端多普勒天气雷达（TDWR）站点，以开发更完整的大南半球湖风行为的三维气候学;（2）收集和分析常规和特殊观察结果（包括上述基于雷达的来自两个移动的气球发射平台的低空气流、风和热力学廓线的视图，和选择性地定位测量从多达8个便携式地面气象站），以检查约10湖微风事件在2008年秋季;（3）将大涡模拟（LES）和传统的中尺度模拟结合起来（天气研究和预报模式），探索这些环流对由不同湖岸范围和大尺度强迫引起的地面加热变化的响应。这项工作的智力价值在于促进我们对热-驱动环流沿着海岸线附近陡峭的地形存在，并增加了知识的过程，控制湖风的发展在干旱环境。它还将详细描述区域尺度天气与GSL生态系统之间的一些复杂相互关系，并更好地量化大气环流对下垫面状态的自然和人为变化的潜在敏感性。这项工作的更广泛影响将包括促进更准确地模拟当地/区域天气和对人口密集的沿海地区城市气象的影响（包括影响能源需求的每日最高温度预报和影响空气质量的通风/混合变化）。将支持研究生和博士后研究助理在协调LES和传统中尺度模拟的设计和执行方面的培训，以及多达20名本科生直接参与GSL附近湖风锋附近的规划和现场数据收集。

Shallow thermally-driven wind circulations commonly develop along extensive coastlines, across which horizontal gradients in solar absorption, evaporation and resultant sensible heating rates are often quite large. Associated sea breeze development along extensive (and generally stationary) coastlines bordered by flat terrain has been well described. These circulations modulate surface air temperatures and boundary-layer mixing, and thus impact both meteorology and air quality in the coastal zone. Less well understood are the structure and dynamics underlying lake-breeze formation in the presence of steep orography and/or variable coastline location, as prone to occur owing to fluctuation of water levels in runoff-fed lakes within arid regions. Such is the situation for the Great Salt Lake (GSL), which is bordered by the major urban area of Salt Lake City and has undergone marked changes in water level and associated projection of its coastline over the past decade. Prior work has described the rudiments of GSL lake breeze formation, including statistics of its frequency and preferred seasonality, but have been confined mainly to a two-dimensional (surface-based) perspective. This new study will (1) analyze archived observations over a 10-year period, which include data from a relatively dense surface mesonetwork ('MesoWest', and its predecessor the 'Utah Mesonet') and a terminal Doppler weather radar (TDWR) site, to develop a more complete 3D climatology of GSL lake-breeze behavior; (2) collect and analyze both routine and special observations (including aforementioned radar based views of low-level airflow, wind and thermodynamic profiles from two mobile balloon-launch platforms, and selectively positioned measurements from up to eight portable surface meteorological stations) to examine ~10 lake-breeze events during Autumn 2008; and (3) apply a combination of large-eddy simulation (LES) and more traditional mesoscale simulations using WRF (the Weather Research and Forecasting model) to explore the response of these circulations to variations in surface heating induced by varying lakeshore extent and large-scale forcing.The intellectual merit of this work rests in advancing our basic understanding of thermally-driven circulations along coastlines in the presence of nearby steep terrain, and increased knowledge of processes that control the development of lake breezes in arid environments. It will also provide a detailed description of some of the complex interrelationships between regional-scale weather and the GSL ecosystem, and better quantify potential sensitivity of atmospheric circulations to both natural and anthropogenic changes in the underlying surface state. Broader impacts of this work will include contributions toward more accurate simulation of local/regional weather and impacts on urban meteorology in densely populated coastal zones (including, for example, daily maximum temperature forecasts impacting energy demands and changes in ventilation/mixing impacting air quality). Training of a graduate student and postdoctoral research associate in the design and execution of coordinated LES and traditional mesoscale simulations will be supported, as will involvement of up to 20 undergraduate students to be directly involved in planning and conducting field data collection in the vicinity of lake-breeze fronts adjacent to the GSL.