Universität zu Köln

Ebell, Kerstin, Nomokonova, Tatiana, Maturilli, Marion and Ritter, Christoph (2020). Radiative Effect of Clouds at Ny-Alesund, Svalbard, as Inferred from Ground-Based Remote Sensing Observations. J. Appl. Meteorol. Climatol., 59 (1). S. 3 - 23. BOSTON: AMER METEOROLOGICAL SOC. ISSN 1558-8432

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Abstract

For the first time, the cloud radiative effect (CRE) has been characterized for the Arctic site Ny-Alesund, Svalbard, Norway, including more than 2 years of data (June 2016-September 2018). The cloud radiative effect, that is, the difference between the all-sky and equivalent clear-sky net radiative fluxes, has been derived based on a combination of ground-based remote sensing observations of cloud properties and the application of broadband radiative transfer simulations. The simulated fluxes have been evaluated in terms of a radiative closure study. Good agreement with observed surface net shortwave (SW) and longwave (LW) fluxes has been found, with small biases for clear-sky (SW: 3.8 W m(-2); LW: -4.9 W m(-2)) and all-sky (SW: -5.4 W m(-2); LW: -0.2 W m(-2)) situations. For monthly averages, uncertainties in the CRE are estimated to be small (similar to 2 W m(-2)). At Ny-Alesund, the monthly net surface CRE is positive from September to April/May and negative in summer. The annual surface warming effect by clouds is 11.1 W m(-2). The longwave surface CRE of liquid-containing cloud is mainly driven by liquid water path (LWP) with an asymptote value of 75 W m(-2) for large LWP values. The shortwave surface CRE can largely be explained by LWP, solar zenith angle, and surface albedo. Liquid-containing clouds (LWP > 5 g m(-2)) clearly contribute most to the shortwave surface CRE (70%-98%) and, from late spring to autumn, also to the longwave surface CRE (up to 95%). Only in winter are ice clouds (IWP > 0 g m(-2); LWP < 5 g m(-2)) equally important or even dominating the signal in the longwave surface CRE.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ebell, Kerstin UNSPECIFIED UNSPECIFIED UNSPECIFIED Nomokonova, Tatiana UNSPECIFIED UNSPECIFIED UNSPECIFIED Maturilli, Marion UNSPECIFIED UNSPECIFIED UNSPECIFIED Ritter, Christoph UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-352556
DOI:	10.1175/JAMC-D-19-0080.1
Journal or Publication Title:	J. Appl. Meteorol. Climatol.
Volume:	59
Number:	1
Page Range:	S. 3 - 23
Date:	2020
Publisher:	AMER METEOROLOGICAL SOC
Place of Publication:	BOSTON
ISSN:	1558-8432
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ARCTIC CLOUD; SURFACE ALBEDO; RADAR; MODELS; FLUXES Multiple languages Meteorology & Atmospheric Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/35255