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Upscale and downscale energy transfer over the tropical P acific revealed by scatterometer winds
Author(s) -
King Gregory P.,
Vogelzang Jur,
Stoffelen Ad
Publication year - 2015
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc009993
Subject(s) - scatterometer , environmental science , climatology , satellite , sea surface temperature , energy cascade , atmospheric sciences , tropical atlantic , meteorology , turbulence , geography , geology , wind speed , physics , astronomy
The direction of the energy cascade in the mesoscales of atmospheric turbulence is investigated using near‐surface winds over the tropical Pacific measured by satellite scatterometers SeaWinds (QuikSCAT) and ASCAT (MetOp‐A). The tropical Pacific was subdivided into nine regions, classified as rainy or dry. Longitudinal third‐order along‐track structure functionsD L L L aand skewnessS L awere calculated as a function of separation r for each region and month during the period November 2008 to October 2009. We find that the results support both downscale and upscale interpretations, depending on region and month. The results indicate that normally energy cascades downscale, but cascades upscale over the cold tongue in the cold season and over the west Pacific in summer months. An explanation is offered based on the heating or cooling of the air by the underlying sea surface temperature. It is also found that the signature of intermittent small‐scale (<100 km) events could be identified in graphs ofS L a, implying that this diagnostic may be useful in the studies of tropical disturbances.