Bart Brashers' Dissertation Abstract
This thesis presents a new method of estimating ocean latent heat flux (LHF) using satellite data.
The surface layer equations derived from Monin-Obukhov similarity theory are closed with empirical
parameterizations, and patched to a mixed layer model yielding a two-layer PBL model. This is the first
proof that such a model can be applied in non-strongly convective situations. Two new retrievals of
moisture parameters are derived, one for the surface to 500 meter integrated water vapor (WB) and one
for the mixed-layer humidity (qm). Inputs include total integrated water vapor retrieved from the Special
Sensor Microwave Imager (SSM/I), sea surface temperature optimally interpolated from retrievals from
the Advanced Very High Resolution Radiometer and buoy/ship measurements (OI SST), and ECMWF
analyzed air-sea temperature difference (T - SST). An analytic relationship between WB and near-sur
face humidity is presented as a replacement for the statistical relationship of Schulz et al. (1993). LHF is
then calculated using the new SSM/I-based retrieval of ML-humidity, SSM/I retrieval of wind speed, OI
SST, and ECMWF T - SST. Model errors are assessed, and the qm method derived in this thesis is found
to perform the best. Systematic errors are small, and random errors are 26 W/m2. Monthly averages of
LHF have been calculated using all available SSM/I data on a 1 by 1 grid for 1992-1997. Differences
with other published climatologies, both those derived from SSM/I data and from traditional data, have
been discussed. Differences between the current work and previous SSM/I methods are evenly split
between model parameterization differences and the new moisture retrieval. Errors due to averaging the
input variables and due to errors in merchant ship measurements dominate the differences between the
current work and traditional climatologies. This analysis establishes the limiting factors in LHF calcula
tion and produces the most accurate LHF climatology to date. It is the first full SSM/I climatology
which will be made available to the general scientific community.
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Bart Brashers
Last modified: Fri Jun 5 10:34:00 PDT 1998