Transcript Folie 1

The ESA DUE GlobVapour
water vapour products
Marc Schröder
on behalf of
the GlobVapour consortium
Deutscher Wetterdienst,
Offenbach, Germany
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Outline
• The project
• Water vapour products with focus on
SSM/I+MERIS
• Validation
• First application
• Conclusions
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Objectives
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Development of multi-annual global water vapour data sets
inclusive error estimates based on carefully calibrated and
intercalibrated radiances.
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Validation of the water vapour products against ground based, insitu and other satellite based measurements.
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Provision of a complete processing system that can further
strengthen operational production of the developed products.
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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.
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Consortium
From left to right:
M. Stengel, T. Steenbergen, B. Bojkov, R. Lindstrot, M. Grzgorski, J. Fischer,
M. Schroeder, J. Schulz, T. Wagner, N. Schneider, R. Leinweber, R. Preusker
Not on the photo:
D. Loyola, S. Slijkhuis, A. Doicu, R. Saunders, M. Ringer, H. Gleisner,
U. Kraemer, M. Goldberg
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Product overview
Total column water vapour, three data sets:
• Combined SSM/I (above ocean) and MERIS (above land) for
2003 – 2008 with composite and monthly products; daylight
product.
• GOME/SCIA/GOME-2 above ocean and land for 1996 – 2008
with weekly and monthly resolution; daylight product.
• (A)ATSR-2 ocean for 1996 – 2008 in daily and monthly
resolution, all day.
Water vapour profiles, one data set:
• Merged IASI+SEVIRI, SEVIRI full disk; three vertical layers
(surf. - 850 hPa, 850 hPa – 500 hPa, 500 hPa - 200 hPa);
October 2007 – December 2008, all day.
Technical features:
• Geographical maps in lat/lon representation.
• netcdf applying the Climate and Forecast metadata standard.
• Data sets include uncertainty measures, number of
AGU Fall Meeting
observations on grid basis, cloud mask, ….
San Francisco, USA, 17 December 2010
Timeline
Dec 2009
Start of project
Mar 2010
Requirements and technical specifications review
Nov 2010
Prototype products, ATBD, Validation Report
(4 month in 2006-2008)
Mar 2011
User Workshop I, jointly with GEWEX Radiation Panel Meeting
Jun 2011
Test products (2006-2008)
Sep 2011
User Workshop II
Nov 2011
Final products (1996-2008)
Nov 2011
End of project
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Validation
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Utilisation of:
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Radiosondes
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 G(R)UAN
 Specific campaigns
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GPS data
 E-GVAP
 SoumiNet
 GSD
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Microwave radiometers
 ARM
 MOL
Lidar data
 NDACC
 MOL
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Aircraft data
 Mozaic
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Other satellite products
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GRAS, COSMIC, CHAMP
MODIS
AIRS
ATOVS
HIRS
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Common metric applied to all products.
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Inter-comparison among GlobVapour products.
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Interim results:
GOME/SCIAMACHY/GOME-2
Principle:
DOAS and measured air mass factor (Wagner et al.
2003) and homogenisation in product space
following (Loyola et al., 2009).
Features:
Global; dx=0.5°; dt=weekly, monthly; day only.
GOME2, March 2007, max=60 kg/m2
See talk of Thomas Wagner today at 12:10
AGU Fall Meeting
San Francisco, USA, 17 December 2010
SSM/I retrieval
Principle:
1D-VAR using RTTOV, both from NWP-SAF.
Recalibration, homogenisation for microwave
observations from SSM/I from CM SAF.
ERA-Int
1D-Var
RGB
uncertainty
AGU Fall Meeting
San Francisco, USA, 17 December 2010
SSM/I retrieval
Optimum between retrieval quality and independency from a-priori
MWR from Nauru ARM site
information is analysed.
AGU Fall Meeting
San Francisco, USA, 17 December 2010
MERIS retrieval
Principle:
New development with the main objective to provide pixel based
retrieval uncertanties:
• Single scattering approximation,
• Forward model for ratio of reflectances at 885 and 900 nm,
• Secant method to find optimal solution.
AGU Fall Meeting
San Francisco, USA, 17 December 2010
MERIS retrieval
Principle (continued):
At coastal regions the MERIS product is also produced but has
decreased quality.
However, quality could be significantly improved through
improved handling of atmospheric scattering under low
reflectance conditions.
Relatively stable radiances >2003 for MERIS.
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Combination of SSM/I + MERIS
bias consideration
Bias consideration:
• Retrieve TCWV from MERIS in sunglint.
• Bias determined/provided but not applied.
Zoom into sun glint regions (08/2007)
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Combination of SSM/I + MERIS
Technical specification and updated result
Combined product:
• Day only; dt=composites, monthly
• MERIS above land + coast (dx=0.05°); SSM/I above ocean (dx=0.5°)
AGUJuly
Fall Meeting
Monthly average for
2007
San Francisco, USA, 17 December 2010
Combination of SSM/I + MERIS
Updated results
Complementary information utilised.
Individual advantages conserved,
in particular, uncertainty estimates remain valid.
Daily composite for 03 July 2007
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Validation
bias of SSM/I+MERIS
Red
Yellow
Blue
Green
Orange
GUAN
AIRS
MODIS NIR (TERRA, AQUA)
MODIS IR (TERRA, AQUA)
ATOVS
See talk of Theo Steenbergen
today at 17:50
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Application
Comparison of GlobVapour TCWV to ERA-Interim and HadGEM2
AGU Fall Meeting
San Francisco, USA, 17 December 2010
More GlobVapour
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Total column water vapour:
- AATSR as input to sea surface temperature retrievals.
- Microwave radiometer (MWR) on ENVISAT to serve sea level
height retrievals.
See talk of Bruno Picard, CLS, today at 12:30
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Water vapour profiles:
- Merged SEVIRI+IASI observations: utilise high temporal and
high vertical resolution.
- IASI water vapour profile assessment.
See talk of Martin Stengel today at 17:20
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Newsletter
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Second volume of the GlobVapour
Newsletter released.
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Inform on progress, events and
products.
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Release: half-yearly.
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Content:
 Introduction.
 Combined SSM/I+MERIS product.
 GOME-like products.
 Validation.
 First application:
Comparison to climate model and
reanalysis.
 Project consortium.
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Webpage
www.globvapour.info
General Information
Breaking News
Downloads:
Newsletter
Products
Documentation
(Requirements
User Guide
Validation Reports)
AGU Fall Meeting
San Francisco, USA, 17 December 2010
Conclusions
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First products can be downloaded and ordered.
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Products in netCDF following CF standard, with full error information
and on easy to handle grid.
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Close link to and feedback from User Group to improve products and
usability.
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Join IASI assessement and/or User Group.
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Specials thanks to:
Jörg Schulz, EUMETSAT;
Katja Hungershöfer, DWD;
Marc Schwärz, Uni. Graz;
www.globvapour.info
Bojan Bojkov, ESA;
NWP-SAF, NWC-SAF…
AGU Fall Meeting
San Francisco, USA, 17 December 2010