The SPARC water vapour assessment II: comparison of stratospheric and lower mesospheric water vapour time series observed from satellites
<p>Time series of stratospheric and lower mesospheric water vapour using 33 data sets from 15 different satellite instruments were compared in the framework of the second SPARC (Stratosphere-troposphere Processes And their Role in Climate) water vapour assessment (WAVAS-II). This comparison...
Main Authors: | , , , , , , , , , , , , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2018-07-01
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Series: | Atmospheric Measurement Techniques |
Online Access: | https://www.atmos-meas-tech.net/11/4435/2018/amt-11-4435-2018.pdf |
Summary: | <p>Time series of stratospheric and lower mesospheric water vapour
using 33 data sets from 15 different satellite instruments were compared in
the framework of the second SPARC (Stratosphere-troposphere Processes And
their Role in Climate) water vapour assessment (WAVAS-II). This comparison
aimed to provide a comprehensive overview of the typical uncertainties in the
observational database that can be considered in the future in observational
and modelling studies, e.g addressing stratospheric water vapour trends. The
time series comparisons are presented for the three latitude bands, the
Antarctic (80°–70° S), the tropics
(15° S–15° N) and the Northern Hemisphere mid-latitudes
(50°–60° N) at four different altitudes (0.1, 3, 10 and
80 hPa) covering the stratosphere and lower mesosphere. The combined
temporal coverage of observations from the 15 satellite instruments allowed
the consideration of the time period 1986–2014. In addition to the
qualitative comparison of the time series, the agreement of the data sets is
assessed quantitatively in the form of the spread (i.e. the difference
between the maximum and minimum volume mixing ratios among the data sets),
the (Pearson) correlation coefficient and the drift (i.e. linear changes of
the difference between time series over time). Generally, good agreement
between the time series was found in the middle stratosphere while larger
differences were found in the lower mesosphere and near the tropopause.
Concerning the latitude bands, the largest differences were found in the
Antarctic while the best agreement was found for the tropics. From our
assessment we find that most data sets can be considered in future
observational and modelling studies, e.g. addressing stratospheric and lower
mesospheric water vapour variability and trends, if data set specific
characteristics (e.g. drift) and restrictions (e.g. temporal and spatial
coverage) are taken into account.</p> |
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ISSN: | 1867-1381 1867-8548 |