EUROCS PACIFIC

Submissions for the intercomparison meeting
in Madrid, December 2002




Table of contents




Individual model results

Here are the results of the GCMs which have been submitted so far. These are individual model results. If you submitted data please check the figures here for any unfortunate (visualization-)errors, as it is better to correct them now than having to deal with them at the meeting in December. If you find any errors please report them here.

Model Participants
ARPEGE MeteoFrance
ECMWF analysis 3-6h
ECMWF analysis 30-36h
ECMWF climate T159
JMA
Met Office, UK
ECHAM MPI
RACMO KNMI
SPEEDY KNMI
HIRLAM standard
HIRLAM revised
Herve Grenier
Martin Koehler, Peter Bechtold
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Hiroto Kitagawa
Adrian Lock
Andreas Chlond, Frank Mueller, Igor Sednev
Geert Lenderink, Erik van Meijgaard
Wilco Hazeleger, Camiel Severijn
Javier Calvo, Colin Jones
Javier Calvo, Colin Jones




Preliminary Intercomparison

The single-level-parameters of the GCMs mentioned above are compared in the figures given in the table below. The figures show the monthly averaged day-average variables of all models, for both diagonal sections (1 and 2, see the case description for more details). The range of values as spanned by the available observational datasets (see also below) is visualized as a grey band.

Single-level-parameter June July August JJA
Sea surface temperature 1, 2 1, 2 1, 2 1, 2
Outgoing longwave radiation 1, 2 1, 2 1, 2 1, 2
Surface downward longwave radiation 1, 2 1, 2 1, 2 1, 2
TOA net shortwave radiation 1, 2 1, 2 1, 2 1, 2
Surface downward shortwave radiation 1, 2 1, 2 1, 2 1, 2
Surface latent heat flux 1, 2 1, 2 1, 2 1, 2
Surface sensible heat flux 1, 2 1, 2 1, 2 1, 2
Total cloud cover 1, 2 1, 2 1, 2 1, 2
Total column water vapour 1, 2 1, 2 1, 2 1, 2
Liquid water path 1, 2 1, 2 1, 2 1, 2
Ice water path 1, 2 1, 2 1, 2 1, 2
Total precipitation (conv. + strat.) 1, 2 1, 2 1, 2 1, 2
Cloud radiative forcing (sw)
1, 2 1, 2 1, 2 1, 2
Cloud radiative forcing (lw)
1, 2 1, 2 1, 2 1, 2


Other single-level-parameters June July August JJAt
Condensed water path
(liquid, ice, graupel, etc.)
1, 2 1, 2 1, 2 1, 2
Theta(1000mb) - SST 1, 2 1, 2 1, 2 1, 2




Observational datasets

The intercomparison between the models gets significantly more meaning when reliable and detailed observations of the relevant parameters are available. To this purpose the archives of a number of measurement programs have been used to extract the data for the period of JJA 1998. The methods used in each program vary, from remote sensing techniques to direct in-situ measurements. We tried to find as many sources for each physical parameter, which should provide some insight in the (dis)agreement between the various datasets.


Relevant datasets for this intercomparison project are available at various locations on the internet, such as the GCSS DIME site, the NASA Langley data center, the NASA Goddard Archive Center, the NOAA-CIRES Climate Diagnostics Center, the IRI/LDEO Climate Data Library, the KNMI Climate Explorer, just to name a few. The archived data for JJA 1998, as well as images of the complete 2D observational fields, are available at these sites. So far the following sets have been included in the intercomparison:

Dataset Acronym Platform Description
Clouds and the Earth's Radiant Energy System CERES TRMM satellite Radiometer measurements of the radiative fluxes at the top of the atmosphere.
Comprehensive Ocean-Atmosphere Data Set / Global Telecommunications System COADS/GTS Ships and buoys In-situ measurements of (near) surface properties and cloud cover.
Earth Radiative Budget Experiment ERBE GOES 9, 10, and ERBS satellites Radiometer measurements of the radiative fluxes at the top of the atmosphere.
Global Precipitation Climatology Project GPCP Various Precipitation, being a composite of SSM/I, TOVS and geostationary IR measurements
International Satellite Cloud Climatology Project ISCCP GOES 9 and 10 satellites Cloud properties and SST, derived from IR and VIS channels.
Optimum Interpolation version 2 OI Ships, buoys and satellites An improved in situ and satellite SST analysis for climate (Reynolds et al., J. Climate 2002, vol.15)
Special Sensor Microwave/Imager SSM/I DMI F11 polar orbit satellite Microwave measurements of atmospheric water vapor, cloud water, and rain rate
TIROS Operational Vertical Sounder TOVS NOAA's polar orbiting satellites ISCCP gridded data product, containing column water vapour and SST. Based on infrared and microwave measurements ( HIRS, MSU, SSU).
Tropical Rainfall Measurement Mission TRMM TRMM satellite Precipitation, cloud ice/water and rain rate, measured by the TRMM Microwave Imager (TMI) and Precipitation Radar (PR).





Observations of single level parameters
Dataset intercomparison



The next table gives the single-level-parameters as derived from the various datasets. Each dataset has a different color. The figures show monthly averaged diurnal averages.

Single-level-parameter Dataset June July August
Sea surface temperatureCOADS, ISCCP, TOVS, OI 1, 2 1, 2 1, 2
Outgoing longwave radiationERBE, CERES 1, 2 1, 2 1, 2
Surface downward longwave radiation- 1, 2 1, 2 1, 2
TOA net shortwave radiationCERES 1, 2 1, 2 1, 2
Surface downward shortwave radiation- 1, 2 1, 2 1, 2
Surface latent heat flux- 1, 2 1, 2 1, 2
Surface sensible heat flux- 1, 2 1, 2 1, 2
Total cloud coverCOADS, ISCCP 1, 2 1, 2 1, 2
Total column water vapourSSM/I, TOVS 1, 2 1, 2 1, 2
Liquid water pathSSM/I, TRMM 1, 2 1, 2 1, 2
Ice water pathTRMM 1, 2 1, 2 1, 2
Condensed water path
(liquid + graupel + ice)
SSM/I, TRMM 1, 2 1, 2 1, 2
Total precipitation (conv. + strat.)GPCP, SSM/I, TRMM 1, 2 1, 2 1, 2
Cloud radiative forcing (sw)CERES 1, 2 1, 2 1, 2
Cloud radiative forcing (lw)CERES 1, 2 1, 2 1, 2





Images/movies of observed 2D fields

Here are images and time-loops of some observed fields in the Pacific area for the period JJA 1998.

Cloud top pressure (ISCCP DX)

These movies beautifully show the general circulation of the low and high clouds in the Hadley cycle. The images are derived from GOES 9 and GOES 10 data, with a gridspacing of 0.5x0.5 degrees and a timestep of 3 hours.

Movies
June 1998
July 1998
August 1998

There were two hurricanes moving into the area in the end of July (Darby) and in the early days of August (Estelle). They had reduced to 'tropical storm' status when they came close to Diagonal 2. See the map of the National Hurricane Center.


Click here for timeseries of the ISCCP cloud top pressure at two fixed locations on Diagonal 1.




Precipitation (TRMM combined, set 3B42)

This should show the spatial and temporal variability of the tropical precipitation patterns in the region. The hurricanes mentioned above can clearly be seen here as well. The 3B42 dataset has a gridspacing of 1x1 degrees and a timestep of 1 day.

Movies
June 1998
July 1998
August 1998

Images (monthly average)
June 1998
July 1998
August 1998





Last update December 13, 2002 by Roel Neggers.


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