GRAPE Latest News

• 28th November 2009:

We are pleased to announce an update to the GRAPE aerosol and cloud dataset, as available from the BADC. The data record has been extended and a bug has been fixed, with this new version known as v3.1. This update takes three parts:

1. A problem was found and fixed in the calculation of the cloud ice water path in level 2 and level 3 files. All other variables are unaffected. It is recommended that users who forsee an interest in this variable reacquire any products they may have; files acquired prior to 26th November 2009 contain the bug. If you are unable to download the new version of the dataset, we can provide IDL code to fix the ice water path manually. Please get in touch if you have any queries about this.

2. The ATSR-2 portion of the dataset has been extended by processing the newly-available level 1 data from January 2001 onwards, meaning the ATSR-2 portion of the GRAPE dataset now continues up to June 2003. Both level 2 and level 3 products are available.

3. The first set of products derived from the AATSR sensor are now available. These may be distinguished from the ATSR-2 products as the file names contain the string 'aatsr' instead of 'atsr2'. At present, level 2 and 3 products from the start of the record (July 24th, 2002) to the end of December 2003. These products may be used in the same manner as those derived from ATSR-2, and are stored on the BADC in the same directory structure as the ATSR-2 files.

We hope to further extend the GRAPE dataset to include the AATSR record up to the end of 2008 early in the New Year.

At present we are working on algorithm and validation papers for the cloud portion of the dataset; the aerosol products included are dealt with in the following:

Algorithm: http://www.atmos-meas-tech.net/2/679/2009/amt-2-679-2009.html

Validation and trends: http://www.atmos-chem-phys-discuss.net/9/21581/2009/acpd-9-21581-2009.html

As a reminder of other useful links, the GRAPE archive may be freely accessed here.

The updated product user guide is here

• 29th April 2009:

We are happy to inform you that version 3 of the ORAC-ATSR cloud and aerosol dataset, processed in the framework of the GRAPE project, is now available to download on the BADC.

The version 3 dataset consists of the ATSR-2 record from June 1995 - January 2001, with January - June 1996 absent due to instrumental failure. As well as individual orbit files at 3x4 km resolution, we have produced monthly mean data products at 1 degree and 2.5 degree resolutions. File format (HDF5, consistent format to the previous version) and example products are detailed in the GRAPE products user guide

We recommend any users with Version 1 or Version 2 data upgrade to Version 3.

Over the rest of the year we intend to carry on processing through the ATSR-2 extended record (onwards from January 1995) and the AATSR record (August 2002 - present) with the same algorithm.