Title: Cloud Edge Properties Measured by the ARM Shortwave Spectrometer Over Ocean and Land

Abstract

In this paper, we use the spectrally invariant method to study the variability of cloud optical thickness (τ) and droplet effective radius (r_eff) in transition zones between the cloudy and clear-sky columns observed by Shortwave Array Spectroradiometer-Zenith at the Southern Great Plains Central Facility site (SGP C1) and during the Marine ARM GPCI Investigation of Clouds (MAGIC) field campaign. The spectrally invariant method approximates the spectra in the transition zone as a linear combination of definitely clear and definitely cloudy spectra. The slope and intercept of the linear relations characterize τ and r_eff in the transition region, respectively. The radiative transfer model simulations show that that (i) the slope of the visible band is positively correlated with τ, while (ii) the intercept of the near-infrared band has a high negative correlation with r_eff. We have analyzed 22 cloud edge cases from the SGP and MAGIC and found that from cloud to clear in the transitions, (a) the slopes of the visible band decrease, indicating the decrease of τ toward cloud edges, and (b) the intercepts of the near-infrared band show a much more significant increase at the SGP than from the MAGIC. The results from observed cases suggest that whilemore » τ decreases for all cases, the decrease in r_eff is much more significant for cloud over land at the SGP site compared to the ocean counterpart during the MAGIC campaign.« less

Authors:

Yang, Weidong  ^[1];

• Search DOE PAGES for author "Yang, Weidong"
• Search DOE PAGES for ORCID "0000-0003-2125-6294"

Marshak, Alexander  ^[2];

• Search DOE PAGES for author "Marshak, Alexander"
• Search DOE PAGES for ORCID "0000-0002-3973-1359"

Wen, Guoyong  ^[3]

• Search DOE PAGES for author "Wen, Guoyong"
• Search DOE PAGES for ORCID "0000-0003-2977-4993"

---

+ Show Author Affiliations

1. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Univ. Space Research Association, Columbia, MD (United States)
2. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
3. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Morgan State Univ., Baltimore, MD (United States)

Publication Date:

Wed Jul 24 00:00:00 EDT 2019

Research Org.:

NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)

Sponsoring Org.:

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

OSTI Identifier:

1593962

Grant/Contract Number:  

SC0005457; SC0018045

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Geophysical Research: Atmospheres

Additional Journal Information:

Journal Volume: 124; Journal Issue: 15; Journal ID: ISSN 2169-897X

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; cloud edge; ARM; shortwave spectrometer; spectrally invariant; SGP; MAGIC; transition zone; cloud; cloud-aerosol interaction; air entrainment and mixing; spectral invariance; shortwave spectroradiometer