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| Titel |
ESA Climate Change Initiative (CCI) project GHG-CCI: A project to deliver the Essential Climate Variable (ECV) Greenhouse Gases |
| VerfasserIn |
Michael Buchwitz, Hartmut Boesch, Otto Hasekamp, Guenter Lichtenberg, Cyril Crevoisier, Gabriele Stiller, Martine De Mazière, Dominik Brunner, Frédéric Chevallier, Claus Zehner |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046267
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| Zusammenfassung |
| Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic
greenhouse gases (GHGs). Satellite observations combined with modeling can add important
missing global information on regional CO2 and CH4 sources and sinks required for better
climate prediction. The ESA project GHG-CCI aims at delivering the high quality satellite
retrievals needed for this application. GHG-CCI is one of several projects of ESA’s Climate
Change Initiative (CCI) which will deliver Essential Climate Variables (ECVs). An overview
about the GHG-CCI project will be given. The GHG-CCI core ECV data products are
column-averaged mole fractions of CO2 and CH4, i.e. XCO2 and XCH4, retrieved from
SCIAMACHY on ENVISAT and TANSO on GOSAT. Other satellite instruments
will be used for constraints in upper layers. Important aspects also covered are
calibration, validation and user assessments. Two satellite instruments are currently
in orbit performing radiance measurements which are sensitive to near-surface
CO2 and CH4 concentration changes: SCIAMACHY on ENVISAT and TANSO on
GOSAT. Both sensors enable the retrieval of near-surface sensitive XCO2 and XCH4.
These data products are the core data products generated within GHG-CCI. Using
SCIAMACHY it has already been demonstrated that regional methane emissions can be well
constrained. Within GHG-CCI the SCIAMACHY XCH4 time series will be extended and
SCIAMACHY XCO2 retrieval algorithms will be further improved. GOSAT has only
recently been launched and only initial data products are currently available. With
GHG-CCI European GOSAT retrieval efforts will be strengthened. Which of the
advanced algorithms, which are under development, will be the best for a given data
product still needs to be assessed. For each of the 4 GHG-CCI core data products -
XCO2 and XCH4 from SCIAMACHY and GOSAT - several algorithms will be
further developed and the corresponding data products will be inter-compared to
identify which data product is the most appropriate. This activity, the so-called
"Round Robin exercise", will be performed in the first two years of this project.
Within this phase a number of other activities will also be performed. This includes
calibration improvements, detailed error characterization of the algorithms and
corresponding data products, inter-comparisons, comparisons with reference data, and
user assessments. Data sets and documents will be generated, including a User
Requirements Document (URD), and the compliance of the data products with
the user requirements will be assessed. A number of retrieval algorithms for other
satellite data products will also be further developed and assessed within GHG-CCI
using AIRS, IASI, MIPAS and ACE-FTS. At the end of the 2 year Round Robin
phase a decision will be made which of the algorithms performs best. The selected
algorithms will be used to generate the first version of ECV GHG. Six months of
processing time will be available for processing. The goal is to process all data but it
still needs to be assessed how much computer time is required by time consuming
so-called "full physics algorithms". As a minimum one year of global data will be
processed (mid 2009 to mid 2010 to ensure overlap between SCIAMACHY and
GOSAT). In the last six months of this 3 year project the resulting data products
will be validated and made available to all interested users for user assessment.
The validation will be conducted using the highly accurate and precise ground
based Fourier Transform Spectrometer (FTS) retrievals conducted within the Total
Carbon Column Observing Network (TCCON). In addition, FTS retrievals from
NDACC and in-situ measurements from the GAW and AGAGE networks will be used. |
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