Remote Sensing of Atmospheric Processes over Complex Terrain

Abstract

This chapter describes the application of a variety of remote sensors to complex terrain studies, including sodars, lidars (aerosol mapping and Doppler), clear-air radars and wind profilers, and optical crosswind sensors. It outlines sensor characteristics relevant to operation in complex terrain settings and examines the origin of turbulence microstructure in complex terrain flows, a significant factor in the use of clear-air radars and sodars. It also summarizes the major programs that have made extensive use of remote sensors and promoted their integration with conventional in-situ instruments. Examples and case studies from these programs are then provided including observations of the initiation and destruction of drainage winds. The behavior of quasi-steady drainage winds and their irregularities during marine layer intrusions, seiches, waves, and strong ambient winds are also described. Recent results are presented that extend the use of Doppler lidar in channeled and merging valley flows as well as in the observation of large-scale mountain-plain circulations. The integration of remote and in-situ sensors in a major transport and dispersion study yields further examples of how different measurement methods can complement each other. Future directions in the study of complex terrain processes are suggested that can take advantage of newly developing remote sensors especially in application to larger-scale mountain-valley circulations.