Abstract

The atmospheric boundary layer (ABL) is the turbulent layer that couples the surface to the overlying free atmosphere. Typically the ABL is capped by a thin transition layer (the entrainment zone) characterized by large gradients in temperature and humidity and thus in refractivity. GPS radio occ... Show moreThe atmospheric boundary layer (ABL) is the turbulent layer that couples the surface to the overlying free atmosphere. Typically the ABL is capped by a thin transition layer (the entrainment zone) characterized by large gradients in temperature and humidity and thus in refractivity. GPS radio occultation (RO) remote sensing from low orbiting satellites, possessing high vertical resolution and sensitivity to the vertical refractivity gradients, is an efficient method for monitoring the height of the transition layer, i.e. ABL depth, particularly over the ocean. Over the past years several methods for determining ABL depth based on the structure of RO signals and vertical profiles of different parameters retrieved from the RO signals, such as bending angle, refractivity and humidity, have been explored. We will give an overview and comparison of the methods for determination of the ABL depth by GPS RO. We will also present the results of a study of the spatial and temporal (from seasonal to diurnal) variability of the ABL depth in different regions over the ocean and land based on Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) GPS RO data. Show less