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AATSR Data Formats Products
SST record 50 km cell MDS
BT/TOA Sea record 17 km cell MDS
Vegetation fraction for Land Surface Temperature Retrieval GADS
Topographic Variance data for Land Surface Temperature Retrieval GADS
Land Surface Temperature retrieval coefficients GADS
General Parameters for Land Surface Temperature Retrieval GADS
Climatology Variance Data for Land Surface Temperature Retrieval GADS
Level 0 SPH
Level 0 MDSR
Auxilliary Data SPH with N = 1
1.6 micron nadir view MDS
Summary Quality ADS
Scan pixel x and y ADS
Grid pixel latitude and longtitude topographic corrections ADS
Across-track Band Mapping Look-up Table
Configuration Data GADS
Processor configuration GADS
LST record 50 km cell MDS
Distributed product MDS
Level 2 SPH
10-arcminute mds
Limits GADS
Validation Parameters GADS
BT/TOA Land record 17 km cell MDS
General Parameters GADS
Temperature to Radiance LUT GADS
Radiance to Brightness Temperature LUT GADS
Medium/High Level Test LUT GADS
Infrared Histogram Test LUT GADS
11 Micron Spatial Coherence Test LUT GADS
11/3.7 Micron Nadir/Forward Test LUT GADS
11/12 Micron Nadir/Forward Test LUT GADS
Characterisation GADS
Browse Day_Time Colour LUT GADS
Browse SPH
Grid pixel latitude and longtitude topographic correction ADS
Level 2 SPH
Auxilliary Products
ATS_VC1_AX: Visible Calibration data
ATS_SST_AX: SST Retrieval Coeficients data
ATS_PC1_AX: Level-1B Processing configuration data
ATS_INS_AX: AATSR Instrument data
ATS_GC1_AX: General Calibration data
ATS_CH1_AX: Level-1B Characterization data
ATS_BRW_AX: Browse Product LUT data
Level 0 Products
ATS_NL__0P: AATSR Level 0 product
Browse Products
ATS_AST_BP: AATSR browse image
Level 1 Products
ATS_TOA_1P: AATSR Gridded brightness temperature and reflectance
Level 2 Products
ATS_NR__2P: AATSR geophysical product (full resolution)
ATS_MET_2P: AATSR Spatially Averaged Sea Surface Temperature for Meteo Users
ATS_AR__2P: AATSR averaged geophysical product
Frequently Asked Questions
The AATSR Instrument
Instrument Characteristics and Performance
In-flight performance verification
Instrument Description
Internal Data Flow
Instrument Functionality
AATSR Products and Algorithms
Common Auxiliary data sets
Auxiliary Data Sets for Level 2 processing
Instrument Specific Topics
Level 2 Products
Level 1B Products and Algorithms
Level 1B Products
Instrument Pixel Geolocation
The Level 0 Product
Differences Between ATSR-2 and AATSR Source Packets
Definitions and Conventions
Organisation of Products
Relationship Between AATSR and ATSR Products
AATSR Product Organisation
Data Handling Cookbook
Characterisation and Calibration
Monitoring of AATSR VISCAL Parameters
Latency, Throughput and Data Volume
Data Processing Software
Data Processing Centres
The AATSR Products User Guide
Image Gallery
Breakup of the Ross Ice Shelf
Land cover in the Middle East
Typhoon Saomai
Mutsu Bay, Japan
Deforestation in Brazil
Spatially Averaged Global SST, September 1993
Further Reading
How to use AATSR data
Why Choose AATSR Data?
Why Choose AATSR Data?
Special Features of AATSR
Principles of Measurement
Scientific Background
The AATSR Handbook
SST record 17 km cell MDS
Surface Vegetation class for Land Surface Temperature Retrieval GADS
1.6 micron forward view MDS
12 micron nadir view MDS
12 micron forward view MDS
Summary Quality ADS
Surveillance Limits GADS
Master Unpacking Definition Table GADS
1.6 micron Non-Linearity Correction LUT GADS
General Parameters GADS
Thin Cirrus Test LUT GADS
Fog/low Stratus Test LUT GADS
1.6 Micron Histogram
Browse MDS
ATS_CL1_AX: Cloud LUT data
Pre-flight characteristics and expected performance
Payload description, position on the platform
Auxiliary products
Auxiliary Data Sets for Level 1B processing
Summary of auxiliary data sets
Calculate Solar Angles
Image Pixel Geolocation
Level 0 Products
Acquisition and On-Board Data Processing
Product Evolution History
Hints and Algorithms for Higher Level Processing
Data Volume
Software tools
Summary of Applications vs Products
Geophysical Coverage
Geophysical Measurements
Visible calibration coefficients GADS
Level 1B SPH
LST record 17 km cell MDS
Conversion Parameters GADS
12 Micron Gross Cloud Test LUT GADS
ATS_PC2_AX: Level-2 Processor Configuration data
Level 2 Products
Hints and Algorithms for Data Use
BT/TOA Sea record 50 km cell MDS
BT/TOA Land record 50 km cell MDS
Level 2 Algorithms
Signal Calibration
Site Map
Frequently asked questions
Terms of use
Contact us


2.11.2 Monitoring of AATSR VISCAL Parameters

For ATSR-2, no routine calibration is performed on the visible and near-infrared image data supplied to users. Instead, this must be done explicitly by the user, using the calibration tables provided on the ATSR Project Web site. For AATSR however, a calibration is routinely applied to the visible and NIR channels as part of the L1B product generation.

During processing, the calibration parameters used for AATSR are taken from an auxiliary file, ATS_VC1_AX, which is based on calibration data taken from a previous orbit. Therefore, the processing chain does not directly apply calibration data from the orbit being processed. This is because the point at which the VISCAL unit is illuminated by the Sun occurs in the middle of the orbit, and the initial processing steps are applied on a scan-by-scan basis. This means that these VISCAL parameters could only be applied by making two passes over the orbit, one to extract the VISCAL signal and a second to apply the calibration, and this is not possible in the current processing scenario. Consequently the L1b process includes a step to extract and calculate the VISCAL parameters for each orbit (see section ), but these are only written into the product (into ADS 7, Visible Calibration Coefficients ADS), and are not applied to that particular orbit.

The ATS_VC1_AX file will be monitored and updated daily to ensure that an optimum set of calibration data are available for off-line processing. Whilst NRT processing will use the latest available ATS_VC1_AX file available within the PDS, it is important that off-line processing uses a file as close as possible to the time of acquisition, to minimise the effect of the build-up of condensation on the FPA relay lens (see Section and Section ). The monitoring activity will take place according to the following procedure:

  1. Under normal circumstances between 1 and 4 orbits of L0 data are received by the FOS team each day. These are processed to derive the exact visible channel calibration coefficients for each of these orbits. This is effectively a repeat of the IPF processing described in Section . If no Level 0 data are received, NRT VC1 file.
  2. Each day produces between 1 and 4 NRT VC1 files. Each file generated is checked for discontinuities with respect to the recent trends in slope and noise. The last file in the sequence is delivered to the IECF for onward distribution to the PDS. In addition, VISCAL history files based on the results of the L0 processing are maintained by the FOS team and long-term plots are made available for relevant meetings and reviews.
  3. The selected file is transferred to the PDS, where it will be made available for off-line processing.
  4. NRT processing will use the closest possible ATS_VC1_AX file from those already in the PDS archive.
  5. Details of the monitoring and quality assurance procedures applied to the AATSR visible channel calibration parameters can be found in Technical Note PO-TN-RAL-GS-0503 "Routine VISCAL Production" Ref. [1.20 ] .