4 research outputs found
Probability Distribution Characteristics for Surface Air–Sea Turbulent Heat Fluxes over the Global Ocean
To analyze the probability density distributions of surface turbulent heat fluxes, the authors apply the twoparametric
modified Fisher–Tippett (MFT) distribution to the sensible and latent turbulent heat fluxes
recomputed from 6-hourly NCEP–NCAR reanalysis state variables for the period from 1948 to 2008. They
derived the mean climatology and seasonal cycle of the location and scale parameters of the MFT distribution.
Analysis of the parameters of probability distributions identified the areas where similar surface turbulent fluxes
are determined by the very different shape of probability density functions. Estimated extreme turbulent heat
fluxes amount to 1500–2000 W m22 (for the 99th percentile) and can exceed 2000 W m22 for higher percentiles
in the subpolar latitudes and western boundary current regions. Analysis of linear trends and interannual variability
in the mean and extreme fluxes shows that the strongest trends in extreme fluxes (more than 15 W m22
decade21) in the western boundary current regions are associated with the changes in the shape of distribution.
In many regions changes in extreme fluxes may be different from those for the mean fluxes at interannual and
decadal time scales. The correlation between interannual variability of themean and extreme fluxes is relatively
low in the tropics, the SouthernOcean, and the Kuroshio Extension region.Analysis of probability distributions
in turbulent fluxes has also been used in assessing the impact of sampling errors in theVoluntaryObserving Ship
(VOS)-based surface flux climatologies, allowed for the estimation of the impact of sampling in extreme fluxes.
Although sampling does not have a visible systematic effect onmean fluxes, sampling uncertainties result in the
underestimation of extreme flux values exceeding 100 W m22 in poorly sampled regions
Global Air–Sea Fluxes of Heat, Fresh Water, and Momentum: Energy Budget Closure and Unanswered Questions
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The Assimilation of Satellite Derived Sea Surface Temperatures into a Diurnal Cycle Model
Estimating air-sea fluxes of heat, freshwater and momentum through global ocean data assimilation
Spectral properties of whitecaps are of importance for color ocean remote sensing and aerosol optical thickness probing from satellite-based instruments. They also influence planetary albedo and climate. In particular, whitecaps may affect the response of the climate system to changes in greenhouse gases and other atmospheric constituents. Several experimental measurements of whitecap spectral reflectance have been performed both in the surf zone and in the open ocean, which indicate that oceanic foam cannot be considered as a gray body (e.g., for satellite remote sensing techniques). This paper is devoted to the interpretation of experiments performed in terms of the radiative transfer theory. Only the case of a semi-infinite foam is studied in detail. However, results can be easily extended to the case of finite foamed media having large optical thickness. The model introduced is capable of explaining main features observed, like a sharp decrease of
the foam spectral reflectance in the infrared as compared with the visible part of the
electromagnetic spectrum and a high correlation of the foam reflectance R and the water absorption coefficient a. A simple method to retrieve the spectral dependence of a from the spectral foam reflectance R is proposed