Satellite Remote Sensing of Evaporation over Sea
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3 February 1993
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4 February 1993
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Figure 16.4: Time series for 3 and 4 February 1993 in the western equatorial Pacific Ocean:
(a) Hourly means of ~TO.l (-), ~T4 (. . .), skin temperature (- - -) and bulk temperature 0.1
m depth (0), (b) hourly means of shortwave net flux (0), longwave net flux (0 ), latent ( ... ),
sensible (- - -) and total heat flux (-), (c) hourly means of surface wind speed (-) and hourly
observations of cloud cover (0 00).
cloud amounts and descreasing wind speeds at the beginning of 4 February cause again increasing temperature differences which occupy values near 0.4 K shortly after sun set. Near 6
UT pronounced differences have been observed between ~TO.l and ~T4 which are caused by
heating due to strong solar radiation absorbed in the upper centi- and decimetres which are
less pronounced at greater depth because of lacking wind mixing. Surface cooling by turbulent
heat and longwave radiation transfer with flux densities below -200 W 1m 2 takes place in the
following night . In the second half of 4 February again deep cumulus convection is developed.
At wind speeds of about 6 mls ~T is decreased to -0.5 K. The cause for the greater differences
with respect to the previous day might be due to wind-speed fluctuations not seen in the hourly
mean. On 3 February near 22 UT the wind speed reached peak values higher than 8 mls for