Ground-Based Water Vapor Retrieval in Antarctica: An Assessment
Date Issued
2016
Author(s)
Abstract
The atmospheric water vapor is an important indicator
of the Earth’s climate state and evolution. We therefore
aimed at calculating the content and long-term variation of the
precipitable water vapor at five coastal Antarctic stations, i.e.,
Casey, Davis, Mawson, McMurdo, and Mario Zucchelli. To do
that, we processed the 12-year time series of GPS and radiosounding
(RS) observations acquired at those stations, with the purpose
of ensuring the utmost accuracy of the results adopting
homogeneous, consistent, and up-to-date processing strategies for
both data sets. Using the two fully independent techniques, rather
consistent contents and seasonal variations of precipitable water
were detected, mainly ranging from 1 (Austral winter) to 10 mm
(Austral summer). At each site, correlation coefficients varying
from 0.86 to 0.91 were found between the GPS and RS time series,
with mean discrepancies ≤0.75 mm. There is no clear indication
regarding the possible dry or wet biases of one technique with
respect to the other, with only a notable GPS wet bias identified
at Mawson and a dry bias at Casey that, nevertheless, correspond
to an average difference of < 1 mm on the two series; the biases
at the other sites are much smaller. Although extremely small, i.e.,
ranging from−0.03 to 0.04 mm/year, the linear trends of the series
are not always consistent in sign. In accordance with the major
climate models, the RS linear trends are mostly positive, whereas
depending on the site, GPS exhibits a (very small) decrease or
increase in water vapor.
Volume
54
Issue
5
Start page
2935
Issn Identifier
0196-2892
Ads BibCode
2016ITGRS..54.2935N
Rights
open.access
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