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The GlobVapour project has been successfully ended on the 31st March 2012.



Retrieved TCWV from MERIS VIS/NIR




Project Manager:

Dr. Marc Schröder (DWD)


Technical Officer:

Dr. Bojan R. Bojkov (ESA)

User Help Desk

Data Request & Technical Support:

Dr. Marc Schröder (DWD)

The Project


Climate change has the potential to lead to unprecedented social, economic, and demographic changes, if projections from climate models become reality. The IPCC Fourth Assessment Report clearly indicates that Earth’s climate is already changing and in some regions more rapidly than it has been predicted (Lemke et al. , 2007 and Trenberth et al., 2007). Thus, the degree of change is uncertain and depends on the model used for the prediction, e.g. the predicted change of temperature changes by the end of the century vary by over a factor of two. To allow society to take informed decisions on mitigation and adaptation measures, quantitative estimates of the current rate of climate change and improved climate prediction is mandatory. Especially the exact knowledge of changes in the water cycle poses a challenge in research consistently. The changes are very small, e.g. the expected decadal change in total column water vapour is only 1.3 % (Ohring et al., 2004) compared to day to day weather fluctuations or even seasonal to inter-annual climate variations.

Water vapour is a key climate variable. In the lower troposphere, condensation of water vapour into precipitation provides latent heating which dominates the structure of troposperic diabatic heating. It is also the most gaseous source of infrared opacity in the atmosphere, accounting for about 60 % of the natural greenhouse effect for clear skies, and provides the largest positive feedback in the model projections of climate change.

Most of the water vapour sources can be found in the boundary layer but the major contribution to feedback is from mid to upper tropospheric humidity. Unfortunately, difficulties in observing water vapour in the upper troposphere have long hampered both observational and modelling studies, and significant limitations remain in coverage and reliability of observational humidity data sets.

Current long-term climate data sets are based mainly on observations by the operational satellite systems that primarily were build to support short-term weather and environmental prediction applications. Many problems are associated with this as for instance instrument calibrations lack traceability, sensors and onboard calibration sources degrade in orbit, orbital drift changes the satellite observation time during the lifetime of the satellite, and the need of stitching together a series of overlapping satellite observations over time. All this can introduce artefacts into long-term time series and needs careful attention when a data set is produced. Furthermore, a problem to almost all data sets produced up to now is missing information on the uncertainty of the estimates in the end product. This can only be realised if a full chain of error propagation from the radiance observation to the product on a regular grid is established. The DUE GlobVapour Project tries to achieve this for its data sets.


Project Overview

The DUE GlobVapour project started on 01 December 2009 followed by its first meeting on 15 March 2010, and reviewing of the requirements baseline and the technical specifications on 16 March. Its main objective (see also below for more details) was to provide long-term coherent water vapour data sets exploiting the synergic capabilities of different EO (ESA and non-ESA) missions allowing for improved accuracies and enhanced temporal and spatial sampling better than those provided by the single sources. It was envisaged that successful concepts from the project can ensure a sustainable provision of the data. The project's scientific set-up and progress was closely attended by the User Group.

Representatives of all participating organisations (Deutscher Wetterdienst (DWD), Freie Universität Berlin (FUB), Deutsches Zentrum für Luft- und Raumfahrt (DLR), UK MetOffice (UKMO), Brockmann Consult (BC), Danmarks Meteorologiske Institut (DMI) and Max-Planck Institut für Chemie (MPI-C)) have met at the DWD headquarters in Offenbach, Germany, to discuss retrieval methods, algorithm implementation, data acquisition and preparation aspects, as well as on the high-level system approach for the Kick-Off. In January 2012, the final meeting took place in Frascati/Italy, where the project partners have summarised their project achievements and the data users have illustrated their GlobVapour studies. They also gave feedback about the data quality and data handling.

The above mentioned consortium was particularly suitable to perform the bridging between pure research projects and sustained provisions of satellite climate data records. Profound expertise in object oriented software development concerning data processing systems in the field of Earth Observation and the contact to and consideration of existing and potential new users was also covered by project partners.

The objective of the DUE GlobVapour project was to support users' requirements for a long time series of satellite borne global water vapour measurements.



The DUE GlobVapour project has developed, validated and applied novel water vapour climate data sets derived from various sensors maximising the use of ESA data but also use other important space based data. More specifically, the successfully executed objectives of the GlobVapour project were:

  • Development of multi-annual global water vapour data sets inclusive error estimates based on carefully calibrated and inter-calibrated radiances.
  • Validation of the water vapour products against ground based, airborne and other satellite based measurements taking into account the individual error structures of the individual observations as far as possible.
  • Provision of a first assessment of the quality of five different IASI water vapour profile algorithms developed by the project contractors and outside groups.
  • Provision of a complete processing system that can further strengthen operational production of the developed products.
  • Demonstration of the usage of the products in the field of climate modelling, also applying alternative ways of climate model validation using forward radiation operators.
  • Promoting the strategy of data set construction and the data sets to the global scientific and operational community.

Requirements Baseline and Technical Specifications

On 16 March 2010 the GlobVapour project successfully passed a review, the Requirements Baseline and Technical Specification Ready (RER). Under review were the Requirements Baseline Document (RBD), the Technical Specifications Document (TSD), the Data Acquisition Plan and the Software Development Plan. RBD and TSD will be publicly available through the projects web page.

Building upon the output from the User Consultation Meeting input from the User Group with experts in the field of (regional) climate monitoring and research, NWP, nowcasting, atmospheric chemistry, and synoptical meteorology are summarised in the RBD. The requirements are mainly given in terms of spatial and temporal resolution as well as accuracy. The consortium carefully considered the RBD and constrains from the various satellites instruments and applicable inversion techniques to produce the TSD. A compliance matrix versus the RBD is given for each GlobVapour product in the TSD.

Project Schedule

 Phase 1

1st Dec 2009

15-16 Mar 2010

until May 2010

10-11 Jun 2010

09-10 Nov 2010

until Nov 2010

until Nov 2010






• Start of GlobVapour

• Kick-Off Meeting at DWD/Offenbach

• Consolidation of Requirements and Specifications

• Progress Meeting at FUB/Berlin

• Progress Meeting at MPI/Mainz

• Creation of Diagnostic Dataset and Validation Tools

• Development of Prototype Product:

  ◊ Development of MERIS retrieval scheme

  ◊ Development of SSM/I

  ◊ MWR retrieval scheme

  ◊ Development of ATSR/AATSR retrieval scheme

  ◊ Development of merged IASI/SEVIRI profile product

 Phase 2

1st Dec 2010

8-10 Mar 2011

until Aug 2011

24 Jan 2012


until Jan 2012


31 Jan 2012

• Start of Phase-II

• Progress Meeting and User‘s Workshop at ESA/Frascati

• Processor development and test product

• Final Meeting and User Consultation Meeting 3 at ESA-ESRIN
  in Frascati/Italy

• Development of Final Product

  ◊ Scientific Exploitation

• End of Project

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Project Manager: Marc Schröder (DWD)   ·   Technical Officer: Bojan R. Bojkov (ESA)   ·   The web site is hosted at Brockmann Consult