in depth comparison between the French Research
Institute for Exploitation of the Sea (IFREMER)* heat flux estimates with those from Woods Hole Oceanographic
Institution (WHOI)** was performed. One is based on satellite
observations and the other one, on a combination of inputs from
assimilation of remotely sensed, buoy and ship data, and numerical
analyses. The study focuses on the Atlantic sector (70°W-30°E,
45°S-45°N) during 1996-2005 for daily, monthly, and annual time scales
The fluxes as well as the parameters that enter the
bulk formulae are evaluated against buoy observations from the Prediction
and Research Moored Array in the Atlantic (PIRATA; data as available at
http://www.pmel.noaa.gov/pirata/); since WHOI uses PIRATA
observations to adjust errors in its flux estimates, we also use
from three buoy experiments that are not used in assimilation by WHOI.
These are: FETCH (the "flux, etat de la mer, et teledetection
en conditions de fetch variable"), the Baltic Sea Swell Experiment
(BASE), and ROMEO, which was part of a field program off the North Carolina
coast of the United States. It is shown that the differences in latent
heat flux estimates are likely due to differences in specific humidity
used in deriving these two products while those in sensible heat flux
are likely due to differences in air temperature (Figure 1) (Santorelli
et al., 2011).
difference between the IFREMER and WHOI datasets during 1996-2005
for (a) sea surface temperature, (b) specific air humidity,
(c) surface wind speed and (d) air temperature (units are degrees Celsius
for sea surface
and air temperature, gkg-1 for specific air humidity and ms-1 for
surface wind speed).
Experiments were conducted with satellite based estimates of specific
air humidity and air temperature (Jackson et al. (2006, 2009)) in
the IFREMER approach based on the COARE3.0 algorithm. Resulting estimates
of latent and sensible heat fluxes at two buoy locations from the PIRATA
array (12°N, 38°W and 4°N, 38°W) are illustrated (Figures
2 and 3). This resulted in significant improvements in both sensible and latent heat estimates by
the IFREMER method.
Figure 2 Comparison of the 12°N, 38°W PIRATA weekly-averaged (a)
latent heat and (b) sensible heat flux to IFREMER_1, WHOI and IFREMER_2,
IFREMER SST and 10m wind speed and Jackson et al. (2009). 10m specific air
humidity and air temperature) estimates. The time span is
2/1/99-12/26/05; there were 107 values available or comparison. A table of statistics, including
bias, RMSD and correlation coefficient is included (units are
Figure 3 Comparison of the 4°N, 38°W PIRATA weekly-averaged (a) latent
heat and (b) sensible heat flux to IFREMER_1,WHOI and
IFREMER_2 (IFREMER_1 SST and 10m wind speed and Jackson et al. 10m
specific air humidity and air temperature) estimates. The time span
is 2/15/99-12/26/05; there are 138 values available for comparison.
A table of statistics, including bias, RMSD and correlation coefficient
is included (units are
These two products were selected due to availability of daily values.
Note: IFREMER_1 denotes results from the original IFREMER approach;
IFREMER_2 denotes results from IFREMER_1 when temperature and humidity
are replaced with values from Jackson et al. (2009).
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