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| Titel |
Tropopause Altitude and Temperature Characteristics from GPS Radio Occultation: Climatologies and Trends |
| VerfasserIn |
Therese Rieckh, Barbara Scherllin-Pirscher, Florian Ladstädter, Ulrich Foelsche |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081470
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| Zusammenfassung |
| The tropopause is one of the key regions of the atmosphere as it acts as a transport barrier
between troposphere and stratosphere and thus influences exchange and trace gas
concentrations. For the last decades, radiosonde data have been the most important data
source to study tropopause parameters and their characteristics. Radiosondes measure with
high vertical resolution, but coverage above the southern hemisphere and oceans is poor. The
Radio Occultation (RO) technique, on the other hand, provides profiles of various
atmospheric parameters with high vertical resolution and global coverage. Measuring the
phase delay of GPS signals, its characteristics include high precision and long-term
stability.
In this work, RO temperature data are used to globally determine and analyze the thermal
lapse rate and cold point tropopause. Data from CHAMP, SAC-C, GRACE, and the six
COSMIC satellites are used for this study.
Climatologies on monthly basis give an overview of the spatiotemporal characteristics of
tropopause altitude and temperature, such as the annual cycle for different latitudes or the
occurrence of multiple tropopauses.
We investigate trends in tropopause altitude and temperature by applying multiple regression
analysis to RO data from 2001 to 2010. Global coverage allows to compute latitude
dependent trends. We find negative (positive) altitude (temperature) trends in the
tropics and positive (negative) altitude (temperature) trends at mid latitudes. At
higher latitudes, insufficient spatiotemporal RO sampling and high atmospheric
variability lead to large sampling errors of the climatologies. Due to this reason, and
the rather short time series, only data within 50°N and 50°S are considered here. |
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