Large Eddy Simulations and Atmospheric General Circulation Model simulations investigaing low cloud properties at Oliktok Point

 

Authors

Erika Roesler — Sandia National Laboratories
Darielle Dexheimer — Sandia National Laboratories
Benjamin Hillman Hillman — Sandia National Laboratories
Casey Michael Longbottom — Sandia National Laboratories
Matthew McChesney — SNL
Monty Apple — Sandia National Laboratories
Fred Helsel — Sandia National Laboratories
Mark D. Ivey — Sandia National Laboratories

Category

High-latitude clouds and aerosols

Description

Prevalent clouds located in the first few kilometers of the Arctic atmosphere play an important role in the heating and cooling of the surface below.  We have simulated the Arctic atmosphere with different model configurations with the purpose of understanding how spatial resolution in the atmospheric model affects the simulated low cloud properties. The first type of configuration and resolutions tested include using an Atmospheric General Circulation Model (AGCM) with uniform 2-degree, 1-degree, and a variable resolution with regional refinement from 1 degree to 1/4 degree over the Arctic. The AGCM in this study uses the atmosphere and land components of the E3SMv0 model, which are similar to the CAM (Community Atmosphere Model) and CLM (Community Land Model) of the CESMv1.2 model. The second type of configuration and resolutions tested include using a Large Eddy Simulation, the System for Atmospheric Modeling (SAM) with resolutions ranging from tens of meters to a thousand meters.   We focus on the time period of the AMF3-Oliktok Point deployment (2013 to present).   During this deployment, the intensive operation period called AALCO (Aerial Assessment of Liquid in Clouds at Oliktok) obtained measurements from field campaigns in the months of May, June, September, October, and November between 2015-2017.   The simulated clouds from the above model configurations ​are compared with in situ measurements taken with sensors such as the supercooled liquid water content sensor and sondes strung on a tethered balloon.   Three-dimensional simulations from the SAM model and profiles from the CAM model are compared with the measurements from AALCO and AMF3 such as the KAZR radar and the ceilometer.   The properties of the clouds (i.e., lifetime, phase partitioning, and downwelling radiation) from the simulations are compared with each other to obtain a multi-resolution viewpoint of the low clouds. Challenges of performing these simulations and making comparisons with observations are presented.