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About this product:
Latent heat flux is the non-radiative flux of heat from the earth's surface to the atmosphere that is associated with the evaporation of water vapor at the surface and subsequent condensation of water vapor in the troposphere. Over warm water latent heat moistens the lower troposphere. It is "latent" becasue it is stored in the internal energy of the water molecules that is later released during condensation.
The convention of Sellers(1965) and Oke(1987) is followed, i.e., non-radiative fluxes directed away from a surface are positive. Thus positive values indicate a loss of heat from the ocean and negative values indicate a gain. Evaporation is a cooling process for the ocean becasue energy is removed from the water as molecules escape the surface. This casues the surface temperature to decrease.
Calculations are made using the TOAGA/COARE equations of Fairall (1996) coded by Pawlowicz, Beardsley, Lentz, Dever, & Anis into version 2.0 of the MATLAB toolbox AIRSEA (http://www.agu.org/eos_elec/00179e.html). The input variables are the east and north wind components measured at 3 m above the surface, the east and north ocean surface currents measured at 2 m below the surface, the air temperature, air pressure and relative humidity measured at 3 m above the surface, and the sea surface temperature measured at 2 m below the surface.
Time: All of the graphs on the page share the same time axis which is located on the bottom of each graph. The time step of the data is half-hourly. As you move from left to right along the time axis, you are moving forward in time. Time is always given in UTC (Universal Coordinated Time).
Data that have passed quality control standards are plotted in blue. Interpolated data are plotted in red.
When there are gaps of no more than 90 minutes, the missing data is linearly interpolated across the gap. When the gap is longer than 90 minutes but less than two days, the missing data is interpolated with a spectral procedure based on the Lomb periodogram that was developed in house.
The first plot shows the quality controled data without any filtering. The second plot shows the three-hour filtered data which eliminates much of the noise. The third plot shows the 40-hr filtered data which is intended to show the long-term response.
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