TY - JOUR
T1 - Wintertime wind forcing and sea surface cooling near the South India tip observed using NSCAT and AVHRR
AU - Luis, Alvarinho J.
AU - Kawamura, Hiroshi
N1 - Funding Information:
The NSCAT wind data were made available by COAPS, Florida State University, Tallahassee; sea surface temperature data were obtained from the NASA Physical Oceanography Distributed Active Archive Center at the Jet Propulsion Laboratory, California Institute of Technology, Pasadena and Figure 1 was drawn from ETOPO5 (1988) from NOAA, National Geophysical Data Center, Boulder, Colorado ( http://www.ngdc.noaa.gov/mgg/global ). This study is supported by the National Space Development Agency of Japan. Discussions with Prof. Kimio Kanawa, Faculty of Geophysics, Tohoku University, were very useful. This report benefited from the suggestions and comments from three anonymous reviewers, one of whom went out of the way to correct some of our careless mistakes in the draft version. We thank them all.
PY - 2000/7
Y1 - 2000/7
N2 - This report addresses a case of topographic air-sea interaction in the Gulf of Mannar, near the Indian tip, for the winter monsoon of 1996-1997. Using high spatial resolution NASA-Scatterometer (NSCAT) wind data, a 1°x1°region of strong wind is identified in the Gulf during the peak of the winter monsoon. The characteristic topography of South India and Sri Lanka and their orientation to the monsoon wind tend to channel this strong wind. Air-sea heat flux analyses, using the NSCAT wind and the European Center for Medium-Range Weather Forecast objective analyses surface data, reveal that the strong winter monsoon bursts cause large latent heat loss (180 W/m2) from a wind-fetch region centered on 7.5°N, 77.5°E during January. Weak air-sea temperature gradients result in weak sensible heat loss (<15 W/m2) from the ocean. The ocean response to this forcing is examined using weekly and monthly mean satellite-derived sea surface temperature (SST) maps; these indicate a sea surface cooling of about 1°C along the axis of the wind flow. A by-product of this cooling is an emergence of a SST front along the periphery of the strong wind-stress region. Time-series analyses of the surface meteorology reveal that this forcing has a periodicity of about 15 days, with a peak during the last week of December. Wind stress curl derived from, the NSCAT wind data exhibits high negative values (anticyclonic Ekman pumping) on a 2-week time scale, concomitant with strong wind bursts. The features observed in the Gulf of Mannar are similar to those reported from some other locations. (C) Elsevier Science Inc., 2000.
AB - This report addresses a case of topographic air-sea interaction in the Gulf of Mannar, near the Indian tip, for the winter monsoon of 1996-1997. Using high spatial resolution NASA-Scatterometer (NSCAT) wind data, a 1°x1°region of strong wind is identified in the Gulf during the peak of the winter monsoon. The characteristic topography of South India and Sri Lanka and their orientation to the monsoon wind tend to channel this strong wind. Air-sea heat flux analyses, using the NSCAT wind and the European Center for Medium-Range Weather Forecast objective analyses surface data, reveal that the strong winter monsoon bursts cause large latent heat loss (180 W/m2) from a wind-fetch region centered on 7.5°N, 77.5°E during January. Weak air-sea temperature gradients result in weak sensible heat loss (<15 W/m2) from the ocean. The ocean response to this forcing is examined using weekly and monthly mean satellite-derived sea surface temperature (SST) maps; these indicate a sea surface cooling of about 1°C along the axis of the wind flow. A by-product of this cooling is an emergence of a SST front along the periphery of the strong wind-stress region. Time-series analyses of the surface meteorology reveal that this forcing has a periodicity of about 15 days, with a peak during the last week of December. Wind stress curl derived from, the NSCAT wind data exhibits high negative values (anticyclonic Ekman pumping) on a 2-week time scale, concomitant with strong wind bursts. The features observed in the Gulf of Mannar are similar to those reported from some other locations. (C) Elsevier Science Inc., 2000.
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U2 - 10.1016/S0034-4257(00)00081-X
DO - 10.1016/S0034-4257(00)00081-X
M3 - Article
AN - SCOPUS:0033939758
SN - 0034-4257
VL - 73
SP - 55
EP - 64
JO - Remote Sensing of Environment
JF - Remote Sensing of Environment
IS - 1
ER -