Vertical Profiles of Cloud Extinction and Cloud Top Droplet Number Concentration in Warm Clouds Derived from Airborne Lidar and Polarimeter Measurements

^(a) NASA Langley Research Center, Hampton, Virginia, 23681 USA
^(b) NASA Goddard Institute for Space Studies (GISS), New York City, New York, USA
^(c) AMA Inc., Hampton, VA USA
^(d) Coherent Applications, Inc. - Psionic LLC, Hampton, Virginia, USA
^(e) DLR Institute of Atmospheric Physics, Oberpfaffenhofen-Wessling, Germany
^(f) University of Arizona, Tucson, Arizona, USA Lead Author e-mail address: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 9 April 2026

Abstract

NASA Langley Research Center airborne second generation High Spectral Resolution Lidar (HSRL-2) participated in a multiyear (2020-2022) NASA field campaign over the North Atlantic Ocean that studied aerosol-cloud interactions using two coordinated aircraft. One aircraft deployed in situ instruments and flew above, within, and below shallow marine clouds while another aircraft followed the same ground tracks and deployed two remote sensing instruments that sampled near the cloud top. The remote sensing instruments were the HSRL-2 and the Goddard Institute for Space Studies Research Center's Scanning Polarimeter (RSP). The lidar provided profiles of cloud top extinction and average lidar ratios to within 2.5 optical depths into the cloud, and the polarimeter provided size distribution parameters derived from the cloud bow region of the scattering phase function. The measurements are then combined to derive the cloud top droplet number density, Nd. Here we present data products from both the lidar and polarimeter and compare Nd derived from the remote sensing and in situ measurements.