Comparison of columnar water-vapor measurements from solar transmittance methods.
In the fall of 1997 the Atmospheric Radiation Measurement program conducted a study of water-vapor-abundance-measurement at its southern Great Plains site. The large number of instruments included four solar radiometers to measure the columnar water vapor (CWV) by measuring solar transmittance in the 0.94-mum water-vapor absorption band. At first, no attempt was made to standardize our procedures to the same radiative transfer model and its underlying water-vapor spectroscopy. In the second round of comparison we used the same line-by-line code (which includes recently corrected H(2)O spectroscopy) to retrieve CWV from all four solar radiometers, thus decreasing the mean CWV by 8-13%. The remaining spread of 8% is an indication of the other-than-model uncertainties involved in the retrieval.
Schmid
B
B
Michalsky
J J
JJ
Slater
D W
DW
Barnard
J C
JC
Halthore
R N
RN
Liljegren
J C
JC
Holben
B N
BN
Eck
T F
TF
Livingston
J M
JM
Russell
P B
PB
Ingold
T
T
Slutsker
I
I