A DIAL System for High Resolution Water Vapor Measurements in the Troposphere

Abstract

Water vapor is a minor constituent of the atmosphere which is of great importance for many atmospheric processes. Rather small changes in concentration can strongly affect other parameters, e.g. the radiation budget by formation of clouds. In our institute the request for experimental data on water vapor originated from studies of organized convection, where the transport of water vapor and the associated condensation obviously is one of the key processes. From this we derived our definition of the term "high resolution", it is meant to be a spatial and temporal resolution sufficient for studies of at least medium scale convective processes, or in approximate numbers, 30 sec in time, 100 m in height, 5% accuracy within the mixed layer (about 1.5 km). The same system can be used for measurements up to greater heights. Temporal and spatial resolution are of course decreasing with height, but compared to conventional radiosonde measurements this resolution can still be considered "high" throughout the troposphere.