@Article{Plana-FattoriDubuFomiCorr:2004:EsAtWa,
author = "Plana-Fattori, Artemio and Dubuisson, Philippe and Fomin, Boris
Alexeevitch and Correa, Marcelo de Paula",
affiliation = "{CPTEC-INPE-Cachoeira Paulista-12630-000-SP-Brasil}",
title = "Estimating the atmospheric water vapor content from multi-filter
rotating shadow-band radiometry at Sao Paulo, Brazil",
journal = "Atmospheric Research",
year = "2004",
volume = "71",
number = "3",
pages = "171--192",
month = "aug./set.",
keywords = "solar transmission measurements, near-infrared, atmospheric water
vapor content, aerosol optical depth, atmospheric turbidity, Sao
Paulo, Brazil,molecular spectroscopic database, sun photometer,
differential absorption, precipitable water, optical dept, trace
gases, solar, aerosol, radiation, instrument.",
abstract = "Selected measurements performed with Multi-Filter Rotating
Shadow-band Radiometers under cloudless conditions at an urban
tropical site, Sao Paulo, Brazil (23.65degreesS, 46.62degreesW,
800 m above the mean sea level) are analyzed. Water vapor content
(U) values are estimated from the analysis of measurements
performed near 940 run with two bandwidths (10 and 3 5 nm).
Narrow- and wide-band measurements performed near 940 nm are
analyzed separately with the help of line-by-line radiative model
computed transmittances, allowing independent (U) over cap (N) and
(U) over cap (W) estimates. The ratio of these measurements is
also analyzed, allowing a third water vapor content estimate (<(U)
over cap>(NW)). Selected approaches for computing water vapor
absorption are compared, including two line parameter databases
and two line-by-line models. After pooling, all results obtained
from measurements performed during 16 cloudless mornings and
representing the water vapor absorption through HITRAN-2000 line
parameters and CKD-2.4 continuum model, estimates (U) over cap
(N), (U) over cap (W), and (U) over cap (NW) were on average 1.8,
0.5, and 4.0 kg m(-2) lower than respective values provided by
balloon-borne soundings, respectively; and (4, estimates were 3%
to 14% smaller than respective (U) over cap (W) values. Assuming
that the independent values provided by soundings are accurate,
the ad hoc reduction of continuum absorption coefficients to 50%
of values provided by CKD-2.4 model improved the reliability of
narrow-band water vapor content estimates in this study. Lastly,
the influence of aerosol extinction on water vapor content was
minimized from the analysis of measurements performed near 870 and
1035 nm. The corresponding turbidity exponent a assumed values
between 0.7 and 1.1, which is somewhat weaker than those usually
reported for urban conditions. (C) 2004 Elsevier B.V. All rights
reserved.",
copyholder = "SID/SCD",
issn = "0169-8095",
language = "en",
targetfile = "Plana-Fattori_Estimating_.pdf",
urlaccessdate = "13 maio 2024"
}