Cross-valley flow and its impact on the boundary-layer structure investigated by multiple Doppler lidar measurements

该建议解决了边界层气象学中一个未解决的问题，采用了一种新的方法：通过在垂直平原上进行跨山谷方向的最先进的双多普勒激光雷达测量，旨在测量整个山谷横截面的运动学流结构，具有高时空分辨率。尽管跨谷气流对大气边界层的演变和山区地气交换有重要作用，但由于缺乏合适的观测资料，我们对其时空特征的认识仍不完全。不同的跨谷流模式的报告-主要是基于数值模拟和少数观测案例研究。 迄今为止，还没有任何研究能够以高时空分辨率观测整个山谷横截面的运动学结构，以捕捉从微β到中γ尺度（即从几十米到几十公里）的过程。然而，这些是与跨谷流相关的尺度。新的双多普勒技术现在允许检测这些尺度上发生的过程。申请人已成功测试了所需的复杂扫描策略。通过增加无线电探空仪和微波辐射计测量的剖面资料，将进一步评估跨谷气流对热力学ABL结构的影响。这一基本信息对于所有涉及山区地气交换的数值研究都是非常宝贵的，也有助于今后的观测研究，以优化测量战略。

This proposal addresses an unsolved problem in boundary-layer meteorology with a novel approach: by performing state-of-the-art dual-Doppler lidar measurements in a vertical plain in cross-valley direction, it is intended to measure the kinematic flow structure across the whole valley cross section with high spatio-temporal resolution. Although cross-valley flows are expected to play an important role for the evolution of the atmospheric boundary layer and the earth-atmosphere exchange over mountainous terrain, our understanding of their spatio-temporal characteristics is still incomplete – mainly due to the lack of suitable observational data. Different cross-valley flow patterns are reported – mainly based on numerical simulation and few observational case studies. No studies exist so far where the kinematic structure across the whole valley cross section is observed with the high spatio-temporal resolution required to capture processes ranging from the micro-β to meso-γ scale (i.e. from a few tens of meters to a few tens of kilometers). However, these are the scales which are relevant for cross-valley flow. The novel dual Doppler technique now allows detecting processes occurring on these scales. The required sophisticated scan strategies have been successfully tested by the applicant. By adding profile information from radiosonde and microwave radiometer measurements the impact of cross-valley flow on the thermodynamic ABL structure will be additionally assessed. This fundamental information are invaluable for all numerical studies which deal with earth-atmosphere exchange over mountainous terrain and can also assist in future observational studies to optimize measurement strategies.