Please note that eDoc will be permanently shut down in the first quarter of 2021!      Home News About Us Contact Contributors Disclaimer Privacy Policy Help FAQ

Home
Search
Quick Search
Advanced
Fulltext
Browse
Collections
Persons
My eDoc
Session History
Login
Name:
Password:
Documentation
Help
Support Wiki
Direct access to
document ID:


          Institute: MPI für Meteorologie     Collection: Atmosphere in the Earth System     Display Documents



  history
ID: 549012.0, MPI für Meteorologie / Atmosphere in the Earth System
A transitioning Arctic surface energy budget: the impacts of solar zenith angle, surface albedo and cloud radiative forcing
Authors:Sedlar, J.; Tjernström, M.; Mauritsen, T.; Shupe, M.; Brooks, I. M.; Persson, P. O. G.; Birch, C. E.; Leck, C.; Sirevaag, A.; Nicolaus, M.
Language:English
Date of Publication (YYYY-MM-DD):2010
Title of Journal:Climate Dynamics
Journal Abbrev.:Clim. Dyn.
Volume:11
Sequence Number of Article:Online First
Review Status:Peer-review
Audience:Not Specified
Abstract / Description:Snow surface and sea-ice energy budgets were measured near 87.5°N during the Arctic Summer Cloud Ocean Study (ASCOS), from August to early September 2008. Surface temperature indicated four distinct temperature regimes, characterized by varying cloud, thermodynamic and solar properties. An initial warm, melt-season regime was interrupted by a 3-day cold regime where temperatures dropped from near zero to -7°C. Subsequently mean energy budget residuals remained small and near zero for 1 week until once again temperatures dropped rapidly and the energy budget residuals became negative. Energy budget transitions were dominated by the net radiative fluxes, largely controlled by the cloudiness. Variable heat, moisture and cloud distributions were associated with changing air-masses. Surface cloud radiative forcing, the net radiative effect of clouds on the surface relative to clear skies, is estimated. Shortwave cloud forcing ranged between -50 W m-2 and zero and varied significantly with surface albedo, solar zenith angle and cloud liquid water. Longwave cloud forcing was larger and generally ranged between 65 and 85 W m-2, except when the cloud fraction was tenuous or contained little liquid water; thus the net effect of the clouds was to warm the surface. Both cold periods occurred under tenuous, or altogether absent, low-level clouds containing little liquid water, effectively reducing the cloud greenhouse effect. Freeze-up progression was enhanced by a combination of increasing solar zenith angles and surface albedo, while inhibited by a large, positive surface cloud forcing until a new air-mass with considerably less cloudiness advected over the experiment area. © 2010 Springer-Verlag.
External Publication Status:accepted
Document Type:Article
Communicated by:Carola Kauhs
Affiliations:MPI für Meteorologie/Atmosphere in the Earth System
Identifiers:DOI:10.1007/s00382-010-0937-5
The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.