ISAS (In Situ Analysis System) has been developed by Gaillard et al. (2009b), as a tool to produce these gridded fields from objective analysis of in-situ data coming from multiple sources. All the documentation could be find here.
The ISAS grid covers the
globe from 80°S to 90°N with 1/2° Mercator resolution, on 151
standard depth levels between 0 and 2000m. A priori statistics are
needed for the analysis: they were obtained from a previous analysis
of the period 2002-2008 (von Schuckmann, et al. 2010), providing the
following reference fields:
reference fields and statistics are also used by ISAS for
preliminary controls on the dataset and by the CATDS (Centre Aval de
Traitement et des Données SMOS) for the real time validation of SMOS
The in-situ observations used to build our dataset are mainly collected and processed by the Coriolis data centre, which apply a real time quality controls in two steps. First, a set of automatic tests (location and date, spikes...) is applied to the database, followed by a visual checking. The result is that quality flags ranging from 0 (no control) to 9 (missing value) are assigned to each individual measurement. Then, after running daily objective analysis, a diagnostic test detects outliers by screening the analysis residuals. Anomalous profiles are visually checked by an operator. The Coriolis Processing is described in Coriolis report-04-047.
For the needs of GLOSCAL, Coriolis data centre has implemented a near-real time data flow. At the beginning of each month, a new analysis is performed with the data of the previous month, thus providing a dataset of improved quality.
The TSG data are collected within the context of GOSUD international project (Global Ocean Surface Underway Data). The GOSUD dataset is hosted by Coriolis that performs the project agreed real time quality controls on this dataset. For our analysis, only data that have passed delayed mode processing are used. The delayed mode quality control on TSG data is performed by the scientists at LPO, IRD Centres and LEGOS using the software TSGQC (TSG-QC link) developed by US-IMAGO (IRD). There are two levels of control: quality flags and corrections. The quality flags used follows the Coriolis definition and depends on the quality of the data with respect to the climatology, spikes, noise, etc. Then when needed, the time series are adjusted to fit the external data which can be either the water sample analysis (taken aboard) and/or the Argo co-localized data with ship tracks (provided by the LOCEAN). The TSG data set so produced are a contribution
to the GOSUD project and are available in NetCDF Gosud format
The processing flow can be summarized as follows: