Estimating trends in atmospheric water vapor and temperature time series over Germany
Ground-based GNSS (Global Navigation Satellite System) has efficiently been used since the 1990s as a meteorological observing system. Recently scientists have used GNSS time series of precipitable water vapor (PWV) for climate research. In this work, we compare the temporal trends estimated from...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2017-08-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/10/3117/2017/amt-10-3117-2017.pdf |
| _version_ | 1818286923556323328 |
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| author | F. Alshawaf K. Balidakis G. Dick S. Heise J. Wickert J. Wickert |
| author_facet | F. Alshawaf K. Balidakis G. Dick S. Heise J. Wickert J. Wickert |
| author_sort | F. Alshawaf |
| collection | DOAJ |
| description | Ground-based GNSS (Global Navigation Satellite System) has efficiently been
used since the 1990s as a meteorological observing system. Recently
scientists have used GNSS time series of precipitable water vapor (PWV) for
climate research. In this work, we compare the temporal trends estimated from
GNSS time series with those estimated from European Center for Medium-Range
Weather Forecasts (ECMWF) reanalysis (ERA-Interim) data and meteorological
measurements. We aim to evaluate climate evolution in Germany by monitoring
different atmospheric variables such as temperature and PWV. PWV time series
were obtained by three methods: (1) estimated from ground-based GNSS
observations using the method of precise point positioning, (2) inferred from
ERA-Interim reanalysis data, and (3) determined based on daily in situ
measurements of temperature and relative humidity. The other relevant
atmospheric parameters are available from surface measurements of
meteorological stations or derived from ERA-Interim. The trends are estimated
using two methods: the first applies least squares to deseasonalized time
series and the second uses the Theil–Sen estimator. The trends estimated at
113 GNSS sites, with 10 to 19 years temporal coverage, vary between −1.5
and 2.3 mm decade<sup>−1</sup> with standard deviations below
0.25 mm decade<sup>−1</sup>. These results were validated by estimating the
trends from ERA-Interim data over the same time windows, which show similar
values. These values of the trend depend on the length and the variations of
the time series. Therefore, to give a mean value of the PWV trend over
Germany, we estimated the trends using ERA-Interim spanning from 1991 to 2016
(26 years) at 227 synoptic stations over Germany. The ERA-Interim data show
positive PWV trends of 0.33 ± 0.06 mm decade<sup>−1</sup> with standard
errors below 0.03 mm decade<sup>−1</sup>. The increment in PWV varies between 4.5
and 6.5 % per degree Celsius rise in temperature, which is comparable to
the theoretical rate of the Clausius–Clapeyron equation. |
| first_indexed | 2024-12-13T01:32:18Z |
| format | Article |
| id | doaj.art-eb4202229be84cdaa4dfce12d82cf186 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-12-13T01:32:18Z |
| publishDate | 2017-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-eb4202229be84cdaa4dfce12d82cf1862022-12-22T00:03:58ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482017-08-01103117313210.5194/amt-10-3117-2017Estimating trends in atmospheric water vapor and temperature time series over GermanyF. Alshawaf0K. Balidakis1G. Dick2S. Heise3J. Wickert4J. Wickert5German Research Centre for Geosciences GFZ, Telegrafenberg, 14473 Potsdam, GermanyInstitute of Geodesy and Geoinformation Science, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, GermanyGerman Research Centre for Geosciences GFZ, Telegrafenberg, 14473 Potsdam, GermanyGerman Research Centre for Geosciences GFZ, Telegrafenberg, 14473 Potsdam, GermanyGerman Research Centre for Geosciences GFZ, Telegrafenberg, 14473 Potsdam, GermanyInstitute of Geodesy and Geoinformation Science, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, GermanyGround-based GNSS (Global Navigation Satellite System) has efficiently been used since the 1990s as a meteorological observing system. Recently scientists have used GNSS time series of precipitable water vapor (PWV) for climate research. In this work, we compare the temporal trends estimated from GNSS time series with those estimated from European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA-Interim) data and meteorological measurements. We aim to evaluate climate evolution in Germany by monitoring different atmospheric variables such as temperature and PWV. PWV time series were obtained by three methods: (1) estimated from ground-based GNSS observations using the method of precise point positioning, (2) inferred from ERA-Interim reanalysis data, and (3) determined based on daily in situ measurements of temperature and relative humidity. The other relevant atmospheric parameters are available from surface measurements of meteorological stations or derived from ERA-Interim. The trends are estimated using two methods: the first applies least squares to deseasonalized time series and the second uses the Theil–Sen estimator. The trends estimated at 113 GNSS sites, with 10 to 19 years temporal coverage, vary between −1.5 and 2.3 mm decade<sup>−1</sup> with standard deviations below 0.25 mm decade<sup>−1</sup>. These results were validated by estimating the trends from ERA-Interim data over the same time windows, which show similar values. These values of the trend depend on the length and the variations of the time series. Therefore, to give a mean value of the PWV trend over Germany, we estimated the trends using ERA-Interim spanning from 1991 to 2016 (26 years) at 227 synoptic stations over Germany. The ERA-Interim data show positive PWV trends of 0.33 ± 0.06 mm decade<sup>−1</sup> with standard errors below 0.03 mm decade<sup>−1</sup>. The increment in PWV varies between 4.5 and 6.5 % per degree Celsius rise in temperature, which is comparable to the theoretical rate of the Clausius–Clapeyron equation.https://www.atmos-meas-tech.net/10/3117/2017/amt-10-3117-2017.pdf |
| spellingShingle | F. Alshawaf K. Balidakis G. Dick S. Heise J. Wickert J. Wickert Estimating trends in atmospheric water vapor and temperature time series over Germany Atmospheric Measurement Techniques |
| title | Estimating trends in atmospheric water vapor and temperature time series over Germany |
| title_full | Estimating trends in atmospheric water vapor and temperature time series over Germany |
| title_fullStr | Estimating trends in atmospheric water vapor and temperature time series over Germany |
| title_full_unstemmed | Estimating trends in atmospheric water vapor and temperature time series over Germany |
| title_short | Estimating trends in atmospheric water vapor and temperature time series over Germany |
| title_sort | estimating trends in atmospheric water vapor and temperature time series over germany |
| url | https://www.atmos-meas-tech.net/10/3117/2017/amt-10-3117-2017.pdf |
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