Impacts of Synoptic-Scale Dynamics on Clouds and Radiation in High Southern Latitudes

Publication Date

8-28-2024

Document Type

Article

Publication Title

Journal of Geophysical Research: Atmospheres

Volume

129

Issue

16

DOI

10.1029/2023JD040329

Abstract

High-latitudinal mixed-phase clouds significantly affect Earth's radiative balance. Observations of cloud and radiative properties from two field campaigns in the Southern Ocean and Antarctica were compared with two global climate model simulations. A cyclone compositing method was used to quantify “dynamics-cloud-radiation” relationships relative to the extratropical cyclone centers. Observations show larger asymmetry in cloud and radiative properties between western and eastern sectors at McMurdo compared with Macquarie Island. Most observed quantities at McMurdo are higher in the western (i.e., post-frontal) than the eastern (frontal) sector, including cloud fraction, liquid water path (LWP), net surface shortwave and longwave radiation (SW and LW), except for ice water path (IWP) being higher in the eastern sector. The two models were found to overestimate cloud fraction and LWP at Macquarie Island but underestimate them at McMurdo Station. IWP is consistently underestimated at both locations, both sectors, and in all seasons. Biases of cloud fraction, LWP, and IWP are negatively correlated with SW biases and positively correlated with LW biases. The persistent negative IWP biases may have become one of the leading causes of radiative biases over the high southern latitudes, after correcting the underestimation of supercooled liquid water in the older model versions. By examining multi-scale factors from cloud microphysics to synoptic dynamics, this work will help increase the fidelity of climate simulations in this remote region.

Funding Number

DE‐SC0023155

Funding Sponsor

National Science Foundation

Keywords

CAM6 and EAMv1 climate models, clouds and radiation, DOE MICRE and AWARE campaigns, extratropical cyclones, southern ocean, synoptic dynamics

Department

Meteorology and Climate Science

Link to Full Text

Share

COinS