Evaluation Dataset for Passive Imager Retrievals

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Revision as of 11:59, 10 May 2012

Common Database

The Cloud Retrieval Evaluation Workshops (CREWs) provide a forum for international satellite-based cloud retrieval teams to share their experience with state-of-art cloud parameter retrievals from passive imaging satellite observations. The evaluation of passive imager cloud properties retrievals is part of the CREW. A Common Database was built to organize cloud property retrievals from different algorithms from research institutes from Europe and America for passive imagers (MSG, MODIS, AVHRR, POLDER and/or AIRS), complemented with cloud measurements that serve as a reference (CLOUDSAT, CALIPSO, AMSU, MISR) for a number of “golden days”. All CREW participants are cordially welcome to use the datasets for their own studies. Due to our data policy, it is necessary to register in order to have access to the database. It is asked that you offer the institute a co-authorship, if you use their datasets for publications.

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

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

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 coverage F means Full disc and S means swath data along the satellite path.

Acro.	Institute	Contact	Sensor	cmk	cph	ctt	ctp	cth	cod	ref	lwp	iwp	cty	cs	night/day
DLR	DLR	Bugliaro, Luca	SEVIRI	F	F	F			F		F	F
CMS	DWD	Stenger, Martin; Lockhoff, Maarit	SEVIRI	F	F	F			F	F	F	F
EUJ	Eumetsat	Joro, Sauli	SEVIRI	F	F	F	F
EUL	Eumetsat	Lutz, Hans-Joachim	SEVIRI	F	F		F						F
OCA	Eumetsat	Watts, Phil	SEVIRI	F	F		F		F	F
FUB	FU Berlin	Preusker, Rene	SEVIRI	F			F
KMR	KNMI	Roebeling, Rob	SEVIRI	F		F			F	F	F	F
KMR	KNMI	Roebeling, Rob	MODIS	S		S			S	S	S	S
KMR	KNMI	Roebeling, Rob	AVHRR	S		S			S	S	S	S
MFR	Meteo France	Le Gleau, Herve; Derrien, Marcel	SEVIRI	F		F	F						F
UKM	UK Met Office	Francis, Pete	SEVIRI	F	F	F	F			F
MOT	UK Met Office	Taylor, Ruth	SEVIRI	F			F
RMB	KMI	Ipe, Alessandro	SEVIRI	F	F				F
LAR	Nasa Langley	Patrick Minnis	SEVIRI	F	F	F	F	F	F	F	F	F
LAR	Nasa Langley	Patrick Minnis	MODIS	S	S	S	S	S	S	S	S	S
GSF	Nasa Goddard	Steve Platnick	SEVIRI	F		F	F	F	F	F	F	F
GSF	Nasa Goddard	Steve Platnick	MODIS	S		S	S	S	S	S	S	S
SMH	SMHI	Dybbroe, Adam	MODIS	S		S	S	S
SMH	SMHI	Dybbroe, Adam	AVHRR	S		S	S	S
AWG	Wisconsin	Heidinger, Andrew	SEVIRI	F	F	F	F	F	F	F	F	F
ULI	Univ. Lille	Riedi, Jerome	POLDER	S					S

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. The coverage P means profiles and S means swath data along the satellite path.

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	Caliop/CPR	P	P	P	P	P	P	P		P
MSR	IfT	Horváth, Ákos	MISR	S				S

*) Only available for single layer ice clouds
**) Only available for single layer water clouds

Further Information

For questions related to access and use of ICARE ressources send comments or questions to
Ulrich Hamann and Jerome Riedi