Satellite Climatology of Trade Wind Clouds Around Hawaii

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Satellite Climatology of Trade Wind Clouds Around
Hawaii
C. Zhang1, Y. Wang1, A. Lauer1, K. Hamilton1, and
F. Xie2 1IPRC, 2NASA JPL
CALIPSO satellite
Trade Wind inversion height from COSMIC plotted
against CALIPSO determinations of cloud top
height for 45 nearly-coincident soundings,
defined as measurements separated by less than 6
hours in time and 100 km in horizontal distance.
Since 2006, CALIPSO (Cloud-Aerosol Lidar and
Infrared Pathfinder Satellite Observations) has
provided the first detailed space-based
measurements of cloud top heights. To obtain
satellite validation for CALIPSO observations,
this project exploited the special conditions of
the Trade Wind (TW) regime around Hawaii, where
on roughly 80 of the days the marine boundary
layer is capped by a Trade Wind Inversion (TWI),
which is generally thought to coincide closely
with the cloud top level. Cloud top heights for
TW days in this region were derived from CALIPSO
lidar observations and compared with TWI-height
determinations using radio occultation
measurements from the Constellation Observing
System for Meteorology, Ionosphere and Climate
(COSMIC). Near-coincident soundings from the two
satellite systems agree quite well, and regional
spatial analyses of the annual mean values of TWI
and cloud top height display consistent features,
with elevated heights over the leeward portion of
the Big Island and minimum heights northwest of
the Big Island, particularly south of Oahu and
Molokai.
Annual mean height of Trade Wind cloud layer from
CALIPSO and TWI height from COSMIC in km. The
dots show locations of COSMIC soundings.