Title: Cloud Optical Properties Over West Antarctica From Shortwave Spectroradiometer Measurements During AWARE

Abstract

A shortwave spectroradiometer was deployed on the West Antarctic Ice Sheet (WAIS) as part of the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program ARM West Antarctic Radiation Experiment (AWARE). This instrument recorded 1-min averages of downwelling hemispheric spectral irradiance covering the wavelength range 350–2,200 nm with spectral resolution 3 and 10 nm for wavelengths shorter and longer than 1,000 nm, respectively. Using simultaneous micropulse lidar data to identify the thermodynamic phase of stratiform clouds, a radiative transfer algorithm is used here to retrieve optical depth and effective droplet (or particle) size for single-phase liquid water and ice water clouds. The AWARE campaign on the WAIS first sampled typical climatological conditions between 7 December 2015 and 9 January 2016 and then a much warmer air mass with more moisture associated with a surface melt event between 10 and 17 January 2016. Before the melt event most liquid cloud effective droplet radii were consistent with pristine polar maritime clouds (mode radius 13.5 μm) but showed a second local maximum in the distribution (at 8 μm) consistent with colder, moisture-limited conditions. Most ice clouds sampled occurred before the melt event (mode optical depth 4 and effective particle size 19 μm). Duringmore » the melt event liquid water cloud optical depth nearly doubled (mode value increasing from 8 to 14). AWARE therefore sampled on the WAIS two cases relevant to climate model simulations: typical current climatological conditions, followed by warmer meteorology possibly consistent with future increasing surface melt scenarios.« less

Authors:

Wilson, A. ^[1]; Scott, R. C. ^[2]; Cadeddu, M. P.  ^[3];

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Ghate, V.  ^[3];

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Lubin, D.  ^[2]

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+ Show Author Affiliations

1. Utah Dept. of Environmental Quality, Salt Lake City, UT (United States)
2. Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography
3. Argonne National Lab. (ANL), Argonne, IL (United States)

Publication Date:

2018-07-30

Research Org.:

Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of California, San Diego, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Science Foundation (NSF); National Aeronautic and Space Administration (NASA)

OSTI Identifier:

1484684

Alternate Identifier(s):

OSTI ID: 1468369

Grant/Contract Number:  

AC02-06CH11357; SC0017981; PLR-1443549; OCE-1359222; ANT-1543305; NNX15AN45H

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Geophysical Research: Atmospheres

Additional Journal Information:

Journal Volume: 123; Journal Issue: 17; Journal ID: ISSN 2169-897X

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES