Date of Award

3-2022

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

Kyle E. Fitch, PhD

Abstract

Persistent Arctic mixed-phase stratocumulus clouds (AMPS) are important to the surface radiation budget of the Arctic. Their presence produces warming within the boundary layer and at the surface and inaccurately forecasting AMPS can lead to large, erroneous temperature forecasts. A Large Eddy Simulation of a case study of a persistent AMPS cloud was conducted using the Advanced Research Weather Research and Forecasting (WRF-ARW) model. The case examined occurred near Oliktok Point, AK between 26 and 27 April, 2017. The produced cloud pattern and properties of four different microphysics schemes -- P3, Thompson, Morrison, and WSM6 -- are compared to observations. Results show that the Thompson scheme was able to best simulate observed conditions as a result of fewer aerosols acting as ice nucleating particles, which allowed the production of more liquid water within the cloud layer. Thompson was the only parameterization scheme to produce significant cloud liquid water, which resulted in additional cloud top radiative cooling, continued coupling with the surface, and sustainment of the cloud layer. The lack of cloud liquid water produced in the other three schemes resulted in the early dissipation of their cloud layers and, consequently, stronger surface cooling, which led to production of a surface-based inversion layer and a decoupling of the cloud layer. Due to the Thompson scheme's more accurate representation of the cloud structure, it also captured surface and cloud top temperatures which aligned more closely to observations.

AFIT Designator

AFIT-ENP-MS-22-M-084

DTIC Accession Number

AD1167023

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