Lidar remote sensing of cloud formation caused by low-level jets

Abstract

In May 2014, the East Hampton Roads Aerosol Flux campaign was conducted at Hampton University to examine small-scale aerosol transport using aerosol, Raman, and Doppler lidars and rawindsonde launches. We present the results of analyses performed on these high-resolution planetary boundary layer and lower atmospheric measurements, with a focus on the low-level jets (LLJs) that form in this region during spring and summer. We present a detailed case study of a LLJ lasting from evening of 20 May to morning of 21 May using vertical profiles of aerosol backscatter, wind speed and direction, water vapor mixing ratio, temperature, and turbulence structure.We show with higher resolution than in previous studies that enhanced nighttime turbulence triggered by LLJs can cause the aerosol and water vapor content of the boundary layer to be transported vertically and form a well-mixed region containing the cloud condensation nuclei that are necessary for cloud formation.