Di. Cooper et al., HIGH-RESOLUTION PROPERTIES OF THE EQUATORIAL PACIFIC MARINE ATMOSPHERIC BOUNDARY-LAYER FROM LIDAR AND RADIOSONDE OBSERVATIONS, Journal of the atmospheric sciences, 53(14), 1996, pp. 2054-2075
A ''thermostat'' mechanism for cooling the Equatorial Pacific is being
tested with data collected during the Central Equatorial Pacific Expe
riment. The Los Alamos National Laboratory participated by fielding tw
o shipboard lidars that collected nearly continuous data over the Paci
fic from 10 to 21 March 1993 as the ship sailed from Guadalcanal to Ch
ristmas Island. A Raman lidar measured water vapor mixing ratio in the
lower troposphere, especially in the marine atmospheric boundary laye
r (ABL), and an aerosol backscatter lidar measured height and thicknes
s of clouds to an altitude of 20 km. The data collected from these two
lidars were used to determine ocean-atmosphere phenomenology, which i
n turn, affects the climatology of the Central Pacific. Agreement betw
een coincident radiosonde and the Raman water vapor lidar measurements
was typically within +/-0.25 g kg(-1) of water. Divergence between th
e two instruments occurred at transitions between distinct layers in t
he lower marine atmosphere. Reasons for this divergence will be discus
sed. Above the ABL the lidar and radiosonde are in excellent agreement
. A wealth of detail is apparent in the lidar-derived profiles. For ex
ample, there are large variations in water vapor mixing ratio-the expr
ession of the inherent low-frequency, intermittent, atmospheric turbul
ence that produces spatially discrete features such as convective plum
es. These features define the structure and extent of the ABL. Using t
he ABL structural characteristics, an analysis of the relationship bet
ween entrainment zone (EZ) height and observed sea surface temperature
(SST) revealed counterintuitive behavior-that the height of the EZ de
creases as SST increases in the range between 27 degrees and 30 degree
s C.