Messenger - Vol. 4, No. 1, Page 6
Marine scientist receives presidental recognition

     Xiao-Hai Yan, associate professor of applied ocean science in the
College of Marine Studies, has received a prestigious 1994
Presidential Faculty Fellow Award. This award recognizes the
scholarship and leadership of some of the nation's most outstanding
young science and engineering faculty. After a review process
conducted by the National Science Foundation, 15 scientists and 15
engineers are selected annually by the White House.
     The award carries a grant of $100,000 per year for five years,
enabling the recipients to undertake self-designed, innovative
research and teaching projects.
     Two areas of Yan's research, in particular, have received
widespread acclaim. He was the first to show how data from the ocean's
surface gathered by satellite could be used to study processes beneath
the surface. In the past, oceanographers have used satellites to study
ocean phenomena such as surface temperature and wave height. However,
these tools were limited because the infrared, radar and microwave
energy used to "remotely sense" ocean conditions do not penetrate the
water's surface.
     Yan devised computer models that use the available surface data
to determine the depth of the ocean's mixed layer, the upper layer of
water that is relatively uniform in temperature and composition due to
mixing by surface winds. Mixed-layer depth is an important piece of
information for many scientists, ranging from marine biologists
studying the growth of microscopic algae to climatologists working on
computer models of the global climate system.
     Another area of Yan's research involves tracking the temperature
and dynamics of the western Pacific warm pool, a large body of
unusually warm water believed to be the spawning ground of the climate
disturbance known as El Nino. His remote sensing study of the area
from space was the first to confirm a definitive link between ocean
surface temperature and a global climate trend.
     That 1992 study attracted the attention of the national and
international media as well as the scientific community, and Yan's
work subsequently appeared in The New York Times; Science, Time and
National Geographic magazines; and on CNN, BBC and ABC news programs.
     With his award, Yan plans to further his research on the western
Pacific warm pool. Specifically, he would like to integrate all
available types of satellite data to look for more precursors of El
Nino and to predict future variability in the warm pool.
     Many of the effects of El Nino have been well documented,
including devastating shifts in rainfall patterns across the globe and
declines in fish populations resulting from temperature changes in the
eastern Pacific, but the origins of the climate disturbances are still
poorly understood.
     Among his recent discoveries, Yan has found that the direction of
the rotation of the warm pool's center changes shortly before the
onset of a new El Nino event.
                                                          -Beth Chajes