Latitudinal variation of air sea fluxes in the western Indian ocean during austral summer and fall

Kumar, M. R. Ramesh; Rao, L.V.G.

doi:10.1007/bf00121785

Cited by 2 publications

(1 citation statement)

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“…There are no long-term observations of total heat flux in the sea ice zone, although several special ship observations of sensible heat flux and latent heat flux have been made (Kangos 1960;Launiainen and Vihma 1994;Ramesh Kumar and Gangadhara Rao 1989;Viebrock 1962;Wendler et al 1997;Zillman 1972). Most of these are observations of sensible heat and latent heat over the open sea.…”

Section: Comparison With Observational Datamentioning

confidence: 99%

Seasonal Change of the Atmospheric Heat Budget over the Southern Ocean from ECMWF and ERBE Data

Okada

Yamanouchi

2002

J. Climate

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The seasonal variation of the zonally averaged atmospheric energy budget between 60Њ and 70ЊS was estimated. This region is predominantly within the seasonal sea ice zone of the Southern Ocean, including some parts of the Antarctic continent. In the Southern Ocean, seasonal sea ice extent exhibits large amplitudes and affects the surface heat exchange considerably. Seasonal variation of the energy budget and its relationship to the surface condition should be clarified as the basic variation. In spite of its importance, the data to estimate energy budgets are extremely sparse in this sea ice zone. Hence, the global objective analyses with forecasting models are mainly used as data for the present study. The surface energy flux is obtained as a remainder term in the energy budget of the total atmosphere, with the energy divergence and changes to the energy content of the atmospheric column derived from the European Centre for Medium-Range Weather Forecasts (ECMWF) objective analyses, and with the radiation budget at the top of the atmosphere estimated from the Earth Radiation Budget Experiment (ERBE) data.The derived values of the surface flux are not seasonally symmetric. This differs from other latitude bands (e.g., 50Њ-60ЊS) where the variation is symmetric and is driven by shortwave radiation change. The monthly mean surface energy flux shows an immediate increase to the maximum of 116 W m Ϫ2 in May (heating of the atmosphere), and then gradually decreases to the minimum of Ϫ108 W m Ϫ2 in December (cooling of the atmosphere). It is suggested that the asymmetry at 60Њ-70ЊS is due to the effect of seasonal sea ice extent changes on the surface energy exchanges. A comparison of the derived values of the surface flux with the latent heat required for the change in sea ice extent provides some support for this suggestion. The rate of sea ice expansion shows a peak in May when the surface energy flux becomes maximum. The turbulent heat component of the surface energy flux is compared with other estimates of turbulent heat exchange over the Southern Ocean. Suppression of the turbulent heat exchange in late winter derived in the present study, in comparison with those values over open water area, suggests the effect of extended sea ice cover.

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