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Atmosphere-surface interactions over polar oceans and heterogeneous surfaces

Abstract

Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present  More>>
Authors:
Publication Date:
Dec 31, 1995
Product Type:
Thesis/Dissertation
Report Number:
MTL-RAP-264
Reference Number:
SCA: 540310; PA: FI-96:003852; EDB-96:172812; NTS-97:005075; SN: 96001697047
Resource Relation:
Other Information: TH: Thesis (Ph.D.); PBD: 1995
Subject:
54 ENVIRONMENTAL SCIENCES; ARCTIC OCEAN; BOUNDARY LAYERS; MATHEMATICAL MODELS; ROUGHNESS; AIR-WATER INTERACTIONS; TURBULENT FLOW; SURFACES; ICE; TEMPERATURE DEPENDENCE; HUMIDITY; HEAT FLUX
OSTI ID:
399964
Research Organizations:
Finnish Inst. of Marine Research, Helsinki (Finland); Helsinki Univ. (Finland)
Country of Origin:
Finland
Language:
English
Other Identifying Numbers:
Other: ON: DE97714849; ISBN 951-53-0530-6; TRN: FI9603852
Availability:
OSTI as DE97714849
Submitting Site:
FI
Size:
192 p.
Announcement Date:

Citation Formats

Vihma, T. Atmosphere-surface interactions over polar oceans and heterogeneous surfaces. Finland: N. p., 1995. Web.
Vihma, T. Atmosphere-surface interactions over polar oceans and heterogeneous surfaces. Finland.
Vihma, T. 1995. "Atmosphere-surface interactions over polar oceans and heterogeneous surfaces." Finland.
@misc{etde_399964,
title = {Atmosphere-surface interactions over polar oceans and heterogeneous surfaces}
author = {Vihma, T}
abstractNote = {Processes of interaction between the atmospheric boundary layer and the planetary surface have been studied with special emphasis on polar ocean surfaces: the open ocean, leads, polynyas and sea ice. The local exchange of momentum, heat and moisture has been studied experimentally both in the Weddell Sea and in the Greenland Sea. Exchange processes over heterogeneous surfaces are addressed by modelling studies. Over a homogeneous surface, the local turbulent fluxes can be reasonably well estimated using an iterative flux-profile scheme based on the Monin-Obukhov similarity theory. In the Greenland Sea, the near-surface air temperature and the generally small turbulent fluxes over the open ocean were affected by the sea surface temperature fronts. Over the sea ice cover in the Weddell Sea, the turbulent sensible heat flux was generally downwards, and together with an upward oceanic heat flux through the ice it compensated the heat loss from the surface via long-wave radiation. The wind dominated on time scales of days, while the current became important on longer time scales. The drift dynamics showed apparent spatial differences between the eastern and western regions, as well as between the Antarctic Circumpolar Current and the rest of the Weddell Sea. Inertial motion was present in regions of low ice concentration. The surface heterogeneity, arising e.g. from roughness or temperature distribution, poses a problem for the parameterization of surface exchange processes in large-scale models. In the case of neutral flow over a heterogeneous terrain, an effective roughness length can be used to parameterize the roughness effects}
place = {Finland}
year = {1995}
month = {Dec}
}