News

07/03/01

Contact:
Mary Tobin
845-365-8607

Findings that water in low cloud cover offsets effect of sun's temperature reported in "Nature" and "Journal of Climate"

reported in "Nature" and "Journal of Climate"

Hsien Wang Ou

Hsien Wang Ou ("Dick")
Adjunct Professor
Lamont-Doherty Earth Observatory
P.O. Box 1000
Palisades, NY 10964
(845) 365-8338

My research interest encompasses three broad areas:

I am interested in physical processes governing ocean circulation. These include genesis and maintenance of coastal front, tidal rectification, evolution of coastal lead in ice-covered ocean, interaction of ocean current with topography or coastline geometry, generation and evolution of eddies, etc.

I am also interested in physics governing the global ocean circulation. I have constructed an alternative theory based on chaotic mixing, which has produced all the major currents independent of detailed wind distribution. This theory has been extended to a coupled ocean-atmosphere, which can provide a unified explanation of global-scale wind and ocean current.

I like to understand fundamental workings of the climate system, and have attempted to address questions such as what determines the earth's temperature? I have constructed a theory which contains cloud cover as an internal parameter, and a closure based on well-known inefficiency of the atmosphere as a heat engine. The model results suggest that surface temperature is narrowly constrained by water properties, and the earth-like climate can be facilitated by a wide range of solar constant.
Selected Publications:

Ou, H.W. "Geostrophic adjustment: a mechanism for frontogensis," Journal of Physical Oceanography, 14:994-1000 (1984).
Ou, H.W. "Why does the Amazon water flow to the north after its discharge?" Journal of Physical Oceanography, 19:1102-1107 (1989).
Ou, H.W. "Some effects of a seamount on oceanic flows," Journal of Physical Oceanography, 21:1835-1845 (1991).
NATURE Water cools the world (to Nature web site article)
The Earth's climate depends less on the Sun than we might think.
July 3, 2001 by PHILIP BALL

2976 VOLUME 14 J O U R N A L O F C L I M A T E
q 2001 American Meteorological Society -- July 1, 2001
Possible Bounds on the Earth's Surface Temperature (.pdf):
From the Perspective of a Conceptual Global-Mean Model

ABSTRACT
A global-mean model is used here to elucidate possible bounds on the surface temperature of a simplified ocean-atmosphere system. Extending previous one-dimensional models, it has included as internal variables the low-level and high-level cloud covers and the turbulent wind at the surface. The main hypothesis for the model closure is that the conversion rate from the solar to the kinetic energy -- or, equivalently, the rate of internal entropy production -- is maximized, which has been applied with considerable success in past latitudinal models. From the model derivation, it is found that the surface temperature is narrowly bounded below by the onset of the greenhouse effect and above by the rapid increase of the saturation vapor pressure. Because both are largely intrinsic properties of water, the resulting surface temperature is mostly insensitive to detailed balances or changing external conditions. Even with a 50% change of the solar constant from its present-day value, the model temperature has varied by only about 10 K. The reason that the heat balances can be maintained is an internal adjustment of the low cloud cover, which offsets the solar effect. The model offers a plausible explanation of an equable climate in the geological past so long as there is a substantial ocean.

For more information, visit www.ldeo.columbia.edu