Collaborative Research: Parameterization of the Land-Surface Thermal and Moisture Heterogeneities

本研究旨在创建新的基础知识和计算机模型表示，用于在陆地呈现较大热湿度差异的地区进行大气模拟。研究人员将首先在犹他州西部沙漠的playa上进行高分辨率的野外实验，使用转换测量技术，那里的地形特征是相对均匀的粗糙表面，表面温度和土壤湿度在空间和时间上都存在差异。野外试验结果将用于：(1)研究地表温度和湿度波动的时间/空间结构；(2)建立地表温度和湿度差异的新关系或修正。该研究旨在解决在空间平均无法提供均匀场的情况下，在更精细的尺度上表现大气表层（ASL）的异质性所面临的挑战。野外数据将在犹他州Playa地区收集，该地区地形相对平坦，粗糙度可能均匀；但是温度和土壤湿度变化很大。本研究的目标是利用弱分层下收集的现场数据在100米分辨率下进行模拟，以开发新的大涡模拟（LES）参数化；预期提高20%。正在测试的主要假设是，温度和湿度变化的空间结构将在详细的通量测量中得到体现，即使在平坦的地形上也是如此。结果将在LES和中尺度模式中进行测试。最初的试验将在裸露、干燥的土壤条件下进行。更广泛的影响包括与公众进行外展和教育活动；以及改进数值天气预报模式参数化的潜力。

This study seeks to create new fundamental knowledge and computer model representations for atmospheric simulations in regions where the land presents large thermal and moisture differences. The investigators will first conduct a high-resolution field experiment using transformative measurement techniques over the playa in Utah's West Desert, where the terrain is characterized by a relatively uniform rough surface with differences in both space and time of surface temperature and soil-moisture. Results from this field experiment will be used to: (1) investigate the time/space structure of the surface temperature and moisture fluctuations and (2) formulate new relationships or corrections that account for the differences in surface temperature and moisture.The research seeks to address the challenges in representing heterogeneities in the Atmospheric Surface Layer (ASL) at finer scales where spatial averaging cannot be used to provide homogeneous fields. Field data will be collected over the Utah Playa, an area with relatively flat terrain and, presumably, uniform roughness; but variable temperature and soil moisture. The goal of this study is to run simulations at 100-meter (m) resolution using field data collected under weak stratification to develop new Large Eddy Simulation (LES) parameterizations; with anticipated improvements of 20%. The main hypothesis being tested is that the spatial structure of temperature and moisture variations will be represented in the detailed flux measurements, even over flat terrain. Results will be tested in both LES and mesoscale models. Initial experiments will be conducted for bare, dry soil conditions. The broader impacts include outreach and education activities with the public; as well as the potential to improve model parameterizations for numerical weather prediction models.