Medspiration – System Requirements Document - Data User Element

Medspiration
MED-SOC-RS-001_1
System Requirements Document
Issue F
Figure 3-4. The Archive is at the core, receiving data input from CMS and providing the
source of DDS data for SOC. The archive supplies data to the dissemination function.
Periodically the L4 processor uses L2P data from the archive to generate L4 products
which are entered into the archive. Periodically the match-up dataset processor
operates, drawing L2P data from the archive and in situ data from the CORIOLIS facility
at IFREMER to generate MDB records for GHRSST-PP.
Archive
The archive receives L2P data as soon as they are produced at CMS. It receives L4 data
products generated at IFREMER by the L4 processor. It also receives ancillary datasets
of wind speed fields and surface solar irradiance required for the diurnal variability
module of the L4 processor. The archive may receive data that are too old to meet the
operational timeliness requirements of GHRSST-PP. Data are registered when they
enter the archive, MMR records are sent to GHRSST-PP, and the location and timing of
each dataset is entered into a database to facilitate searching. The archive is partitioned
between on-line and off-line storage, and daily back-ups are made.
L4 UHR data production at IFREMER
The L4 UHR data production is performed on a daily cycle. All the L2P and ancillary data
acquired by sensors between 00:00 to 23:59 on day T, which is available in the archive at
06:00 UTC on day T+1, is used to generate L4 product to be delivered by 11:59 on day
T+1. The L4 processor has four modules as shown in Figure 3-6.
The first identifies the measured SST data available for each location and selects
according to quality criteria, defined in a configuration file. All the measured SST data
correspond to skin or subskin observations.
The second module estimates the diurnal variation (DV) of the difference between
SSTskin and SSTfnd, or SSTsubskin and SSTfnd, making use of ancillary data contained
within the L2P products, additional wind speed or SSI data if available, and any regional
factors that are supplied in a configuration file. By this means every L2P SST
measurement is converted to an estimate of SSTfnd.
The third module applies an optimal interpolation (OI) process to all the selected data,
now converted to estimates of SSTfnd, in order to produce an analysed, gridded field of
SSTfnd. It also attaches error estimates to each pixel in the field. This forms the core of
the L4 SST product.
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