GOES moisture transport measurements are capable of quantifying regional variations that are important in understanding climate anomalies such as drought and flood which may be affected by the net transport of upper-tropospheric water vapor into or out of particular regions. The figures below show the net mass flux of vapor across a latitude or longitude wall for two distinct seasons for both 1987 and 1988. The quantities shown are computed using the formula,
where R is the radius of the earth, z is height, lambda is longitude, rho is density, q is specific humidity, v is the north south component of the wind, and phi is latitude.
The above figure presents the results
of applying the above equation to the GOES derived winds and humidity
in the Eastern Tropical Pacific (ETP). During the summer of 1987
(blue arrows), considerably weaker vapor flux was observed across
all boundaries except the north wall. In fact, the greatest seasonal
mass flux during June, July, and August (JJA) of 1988 (green arrows)
was across the eastern wall (-7.71 X 106 kg s-1)
whereas during 1987 there was almost no net seasonal mass vapor
flux along this boundary (+0.09 X 106 kg s-1).
During the Boreal fall (figure below), 1988 is a more active transport
season than 1987 with exceptionally strong poleward mass flux.
The net divergence (convergence) of the mass flux implies anomalies
in vapor distribution that are more meaningful than the magnitude
of the transport across individual walls. More upper-tropospheric
vapor was expelled from the ETP ITCZ during JJA of 1987 as the
net mass flux divergence is about 2 X 106 kg s-1
greater than 1988. During the Boreal fall months of 1988, the
net mass flux divergence was five times that of SON 1987. This
is clearly depicted on the north/south latitude walls in the below
figure.
Last updated on: November 2, 1999