Title: Synoptic Drivers of Atmospheric River Induced Precipitation Near Dronning Maud Land, Antarctica

Abstract

Abstract Atmospheric rivers (ARs) that reach the Antarctic Ice Sheet (AIS) transport anomalous moisture from lower latitudes and can impact the AIS via extreme precipitation and increased downward longwave radiation. ARs contribute significantly to the interannual variability of precipitation over the AIS and thus are likely to play a key role in understanding future changes in the surface mass balance of the AIS. Dronning Maud Land (DML) is one of four maxima in AR frequency over coastal East Antarctica, with AR precipitation explaining 77% of the interannual variability in precipitation for this region. We employ a 16‐node self‐organizing map (SOM) trained with MERRA‐2 sea‐level pressure anomalies to identify synoptic‐scale environments associated with landfalling ARs in and around DML. Node composites of atmospheric variables reveal common drivers of precipitation associated with ARs reaching DML including anomalous high‐low surface pressure couplets, anomalously high integrated water vapor, and coastal barrier jets. Using a quasi‐geostrophic framework, we find that upward vertical motion associated with the occlusion process of attendant cyclones dominates atmospheric lift in AR environments. We further identify mechanisms that explain the variability in AR precipitation intensity across nodes, such as the lift associated with the occlusion process of attendant cyclones and themore » spatial coincidence of ascent induced by the occlusion process and frontogenesis. The latter suggests that ARs making landfall during the mature phase of cyclogenesis result in higher precipitation intensity compared to landfalling ARs that occur during the occluded phase.« less

Authors:

Baiman, Rebecca  ^[1];

• Search DOE PAGES for author "Baiman, Rebecca"
• Search DOE PAGES for ORCID "0000-0002-1801-8618"

Winters, Andrew C.  ^[1];

• Search DOE PAGES for author "Winters, Andrew C."
• Search DOE PAGES for ORCID "0000-0002-1044-3302"

Lenaerts, Jan  ^[1];

• Search DOE PAGES for author "Lenaerts, Jan"
• Search DOE PAGES for ORCID "0000-0003-4309-4011"

Shields, Christine A.  ^[2]

• Search DOE PAGES for author "Shields, Christine A."
• Search DOE PAGES for ORCID "0000-0003-4481-1377"

---

+ Show Author Affiliations

1. Univ. of Colorado, Boulder, CO (United States)
2. National Center for Atmospheric Research (NCAR), Boulder, CO (United States)

Publication Date:

Sat Mar 25 00:00:00 EDT 2023

Research Org.:

University Corporation for Atmospheric Research (UCAR), Boulder, CO (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1970355

Alternate Identifier(s):

OSTI ID: 1972740

Grant/Contract Number:  

SC0022070; DE‐SC0022070

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Geophysical Research: Atmospheres

Additional Journal Information:

Journal Volume: 128; Journal Issue: 7; Journal ID: ISSN 2169-897X

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES