Chapter 3
Surface Fluxes of Momentum, Heat,
and Water Vapor
John D. Albertson, University of California, Davis, CA
Gerard Kiely, University College Cork, Ireland
Marc B. Pariange, University of California, Davis, CA
Abstract
Advances in global scale hydrology and climatology demand an improved understanding of the
interaction between the Earth's surface and its atmosphere. Such an understanding is being
sought through field experiments over the ocean and the land and through the use of remote
sensing. In many cases, the traditional eddy correlation measurement technique to obtain
fluxes of heat and momentum is problematic and it becomes necessary to employ less direct
techniques. In this paper the inertial-dissipation method is reviewed and a refined approach
is presented. The new dissipation model circumvents several of the short-comings inherent to
previous formulations of the dissipation approach. Experimental data are presented to support
new empirical scaling forms for turbulent kinetic energy and scalar variance dissipation rates and
the refined dissipation-flux model is tested. Excellent agreement with direct flux measurements
is obtained.
3.1 Introduction
Momentum and scalar fluxes between the Earth's surface and its atmosphere are fundamental
to issues ranging from watershed management to climate systems, as well as to our basic
understanding of flow and transport in the atmospheric surface layer. Efforts to model the
atmospheric boundary layer (ABL) in itself or as part of a larger climate simulation model
are limited by an inadequate understanding of surface fluxes over the land and the ocean.
Advances in regional and global scale hydro-meteorology must rely on observations of the
exchange between the Earth's surface and its atmosphere. For these observations to be relevant,
they must be made over a spatial scale appropriate to the problem being addressed. Satellitebased instruments hold promise for diagnosing and mapping surface fluxes. However, the
development of reliable algorithms for relating the instrument readings to actual surface fluxes
hinges on a program of careful comparison of algorithm estimates to actual measurements of
the fluxes. Benchmark flux measurements may be acquired through (i) inference from vertical
NATO ASI Series, Vol. I 45
Radiation and Water in the Climate System:
Remote Measurements
Edited by Ehrhard Raschke
© Springer-Verlag Berlin Heidelberg 1996
Surface Fluxes of Momentum, Heat,
and Water Vapor
John D. Albertson, University of California, Davis, CA
Gerard Kiely, University College Cork, Ireland
Marc B. Pariange, University of California, Davis, CA
Abstract
Advances in global scale hydrology and climatology demand an improved understanding of the
interaction between the Earth's surface and its atmosphere. Such an understanding is being
sought through field experiments over the ocean and the land and through the use of remote
sensing. In many cases, the traditional eddy correlation measurement technique to obtain
fluxes of heat and momentum is problematic and it becomes necessary to employ less direct
techniques. In this paper the inertial-dissipation method is reviewed and a refined approach
is presented. The new dissipation model circumvents several of the short-comings inherent to
previous formulations of the dissipation approach. Experimental data are presented to support
new empirical scaling forms for turbulent kinetic energy and scalar variance dissipation rates and
the refined dissipation-flux model is tested. Excellent agreement with direct flux measurements
is obtained.
3.1 Introduction
Momentum and scalar fluxes between the Earth's surface and its atmosphere are fundamental
to issues ranging from watershed management to climate systems, as well as to our basic
understanding of flow and transport in the atmospheric surface layer. Efforts to model the
atmospheric boundary layer (ABL) in itself or as part of a larger climate simulation model
are limited by an inadequate understanding of surface fluxes over the land and the ocean.
Advances in regional and global scale hydro-meteorology must rely on observations of the
exchange between the Earth's surface and its atmosphere. For these observations to be relevant,
they must be made over a spatial scale appropriate to the problem being addressed. Satellitebased instruments hold promise for diagnosing and mapping surface fluxes. However, the
development of reliable algorithms for relating the instrument readings to actual surface fluxes
hinges on a program of careful comparison of algorithm estimates to actual measurements of
the fluxes. Benchmark flux measurements may be acquired through (i) inference from vertical
NATO ASI Series, Vol. I 45
Radiation and Water in the Climate System:
Remote Measurements
Edited by Ehrhard Raschke
© Springer-Verlag Berlin Heidelberg 1996