Evaluation Dataset for Passive Imager Retrievals
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Common Database
The evaluation of passive imager cloud properties retrievals is part of the CREW. Hereto, a Common Database of cloud retrievals from different algorithms is build, which will be filled with retrievals of the different data providers. Below you will find relevant information for uploading your cloud retrievals to the common database. Note: the selected Golden Days are similar to those selected for CREW-2. Thus, providers that already have provided their data for CREW-2, and that do not want to update their datasets or add new ones, do not need to upload their datasets again.
DATASET SPECIFICATIONS
We have selected five Golden Days that are listed in Table 1. During several hours of the selected Golden Days the A-Train satellites aligned with AVHRR on-board NOAA-18. Our evaluation study will focus on these hours. However, we encourage the data providers to upload their datasets of the five Golden Days for the full 24 hrs. The study area is restricted to the SEVIRI full disk. The following data are desired for the Common Database:
- SEVIRI 15 minute data of the MSG disk preferably covering the full 24 hrs during the golden days (5x24hrs);
- MODIS swath data covering the MSG disk preferably covering the full 24 hrs during the golden days (5x24hrs);
- AVHRR swath data covering the MSG disk during the hours where NOAA-18 was aligned with the A-Train satellites
- Other instruments (MERIS/POLDER/..) preferably covering the full 24 hrs during the golden days (5x24hrs).
You can upload your data to the Common Database through the FTP server at ICARE, which is assessable for CREW members after registration. During the registration when asked for a “short description of your project”, please write: Account request for the Cloud Retrieval Evaluation Workshop (CREW).
Table 1: Golden Days that have been selected for the (inter)comparison
| Day | Month | Year | Hours with alignment between A-Train and NOAA-18 |
|---|---|---|---|
| 13 | June | 2008 | 12:00-15:30 |
| 17 | June | 2008 | 22:15-24:00 |
| 18 | June | 2008 | 00:00-01:45 |
| 22 | June | 2008 | 10:30-12:15 |
| 03 | July | 2008 | 10:00-12:00 |
Data Description
The inter-comparison of cloud parameters is done for level 2 products. The products delivered by the different algorithm providers have been converted to a common file format to facilitate direct inter-comparison. Table 2 lists the cloud parameters have been selected for the (inter)comparison:
Table 2: Cloud Parameters that have been selected for the (inter)comparison
| Acronym | Cloud Parameter |
|---|---|
| cmk | cloud mask |
| cph | cloud phase |
| ctt | cloud top temperature |
| ctp | cloud top pressure |
| cth | cloud top height |
| cod | cloud optical depth |
| ref | effective radius |
| lwp | liquid water path |
| iwp | ice water path |
Data Providers and Algorithms
Datasets from 13 retrieval algorithms contributed to the Common Database that was created for the evaluation of cloud properties retrievals in the CREW project. Table 1 lists the provider, the cloud parameters, and the satellites of the 13 datasets in the Common Database. A detailed description of the retrieval algorithms can be found in the
Algorithm discription (only for CREW members, password needed).
Table3: List of Research groups that provided Cloud Parameter retrievals for the Common Database. For each groups the satellite instruments and cloud parameters for which data are provided are given. Where the codes from the cloud parameters are: cmk= cloud mask; cph= cloud phase;ctt= cloud top temperature; ctp= cloud top pressure; cth= cloud top height; cod = cloud optical depth; ref= effective radius; lwp= liquid water path; iwp= ice water path; cty= cloud type, and cs= convective signature. The codes for the satellites are: S = SEVIRI, A = AVHRR, M = MODIS,P = POLDER
| Acro. | Institute | Contact | Sensor | cmk | cph | ctt | ctp | cth | cod | ref | lwp | iwp | cty | cs | night/day | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DLR | DLR | Bugliaro, Luca | S | F | F | F | F | F | F |  | ||||||
| CMS | DWD | Stenger, Martin; Lockhoff, Maarit | S | F | F | F | F | F | F | F | | |||||
| EUJ | Eumetsat | Joro, Sauli | S | F | F | F | F |  | ||||||||
| EUL | Eumetsat | Lutz, Hans-Joachim | S | F | F | F | F | | ||||||||
| OCA | Eumetsat | Watts, Phil | S | F | F | F | F | F | | |||||||
| FUB | FU Berlin | Preusker, Rene | S | F | F | | ||||||||||
| KMR | KNMI | Roebeling, Rob | S,M,A | F | F | F | F | F | F | | ||||||
| MFR | Meteo France | Le Gleau, Herve; Derrien, Marcel | S | F | F | F | F | | ||||||||
| UKM | UK Met Office | Francis, Pete | S | F | F | F | F | F | | |||||||
| MOT | UK Met Office | Taylor, Ruth | S | E | E | | ||||||||||
| RMB | KMI | Ipe, Alessandro | S | F | F | F | | |||||||||
| LAR | Nasa Langley | Patrick Minnis | S,M | F | F | F | F | F | F | F | F | F | | |||
| GSF | Nasa Goddard | Steve Platnick | S,M | F | F | F | F | F | F | F | F | | ||||
| SMH | SMHI | Dybbroe, Adam | M,A | S | S | S | S | |||||||||
| AWG | Wisconsin | Heidinger, Andrew | S,A | F | F | F | F | F | F | F | F | F | | |||
| ULI | Univ. Lille | Riedi, Jerome | P | F | F |
All data are available on the CREW FTP site (registration needed).
The updated SEVIRI retrievals (in the same format for all groups) of CREW-3 are available in L2_SEVIRI_CREW2.
All submitted data (all sensors) in the individual format of the group are available in L2_original_CREW3.
Table4: List of Research groups that provided Reference data for the Common Database. For each groups the satellite instruments and cloud parameters for which reference data are provided are given.
| Acro. | Institute | Contact | Sensor | cmk | cph | ctt | ctp | cth | cod | ref | lwp | iwp | cty | cs | night/day | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CPR | NASA | Stephens Graeme | Cloudsat | P | P | P | P | P* | P* | P* | | |||||
| CAL | NASA | Winker, Dave | Calipso | P | P | P | P | P | P* | P* | P* | | ||||
| AMS | SSEC | Bennartz, Ralph | AMSR | P** | | |||||||||||
| DAR | SSEC | Delanoe, Hogan | Cloudsat/Calipso | P | P | P | P | P | P | P | P | | ||||
| MSR | IfT | Horváth, Ákos | MISR | P | P | |
*) Only available for single layer ice clouds
**) Only available for single layer water clouds
Table4: List of Research groups that provided Simulator data for the Common Database. For each groups the satellite instruments for which simulated radiances are provided are given.
| Acro. | Institute | Contact | Model | Methods |
|---|---|---|---|---|
| MYS | DLR | Faure, Francoise | Mystic | 3 dimensional Monte Carlo |
| DAK | KNMI | Jonkheid, Bastiaan | DAK | doubling adding, lookup table |
| UBK | University of Bremen | Kokhanovsky, Alexander | SCIATRAN | discrete ordinate, finite differences |
Further Information
For questions related to access and use of ICARE ressources send comments or questions to
Ulrich Hamann and Jerome Riedi
