CARS (CSIRO Atlas of Regional Seas) is a digital climatology, or atlas of seasonal ocean water properties: temperature, salinity, dissolved oxygen, nitrate, phosphate and silicate. It comprises gridded fields of mean ocean properties over the period of modern ocean measurement, and average seasonal cycles for that period. It is derived from a quality-controlled archive of all available historical subsurface ocean property measurements - primarily research vessel instrument profiles and autonomous profiling buoys. As data availability has enormously increased in recent years, the CARS mean values are inevitably biased towards the recent ocean state.
CARS2009 covers the full global oceans on a 1/2 degree grid, but until June 2011 only included temperature and salinity fields. The T and S fields were created in July 2009 and were was based on World Ocean Database 2005 (WOD05) [July 2008 Update], surface-pressure-corrected Argo global archives to May 2009, WOCE Global Hydrographic Program (v3.0), and many other datasets available up to 2008. The data was collated from many sources and rigorously screened to form BLUElink Ocean Archive (BOA).
This metadata record describes all CARS parameters, which can then be visualised as a single collection through the portal interface.
CARS is a digital atlas of seasonal ocean water properties
CSIRO Oceans & Atmosphere
Argo - Broad scale Global Array of Temperature/Salinity Profiling Floats
Source data was ship-based CTD and hydrology casts from CSIRO Marine archives (1985-ongoing), the WOCE GHP, and the NODC July08 update of the World Ocean Database 2005, which was a collation of all possible casts from all countries, from earliest records (1990) to 2008. Also includes smaller datasets from other data centres, and Argo and TAO data. Observed data were interpolated to 79 standard depths, and loess mapped to 1/2 degree grid.
Errors may occur in location of cast data. Interpolation from data of irregular spatial distribution will introduce uncertainty into the value assigned to each location (equivalently, the location assigned to a given value.)
"map error" is an estimate of the "Standard Error of the Mean" (unlike OI, loess does not provide an error field.) The data source radius (for the mapping at each grid point) is also stored to give some insight into relative accuracy at different locations, and fields of data variance and RMS mapping-residuals are available.
Logical consistency report
Mapping was optimised to accurately locate horizontal structure and mean values in mapped properties, and to reveal annual and semi-annual signals. Depth layers were only loosely related to adjacent layers, and spatial mapping scales varied between layers. The mapping methods therefore were NOT optimised to resolve vertical structure, although potential temperature inversions in mean and seasonal profiles were substantially suppressed after mapping.
All known reliable published data is used, but this can still be very sparse, especially at depth, and especially for some nutrients. In many places strong interannual signals or eddy noise will be aliased into spatial or seasonal signals, and smoothing can broaden frontal features.
This dataset collection combines the following parameters: temperature, temperature anomaly, salinity, salinity anomaly, dissolved oxygen, nitrate, phosphate and silicate.
Prior to October 2015, these parameters were described and served in separate metadata records, but with new developments of the portal 1-2-3, they have been combined in a single collection for ease of discovery and data access.