Ocean-surface optical parameters: reflectances

Advanced Along-Track Scanning Radiometer multimission data have been reprocessed to provide update retrievals of Sea Surface Temperature (SST) to produce the AATSR Reprocessing for Climate (ARC) dataset.

The Ocean Heat Content ("OHC") is estimated from the measurement of the thermal expansion of the ocean based on differences between the total sea-level content derived from altimetry measurements and the mass content derived from gravimetry data, noted “altimetry-gravimetry”. The Earth Energy Imbalance ("EEI") indicator is derived from the temporal variations of the ocean heat content, i.e. by calculating its derivative (called the ocean heat uptake). The product is delivered in two distinct files. The main one contains the essential variables like Global Ocean Heat Content, Earth Energy Imbalance time series and their relative variance-covariance matrices. The second file contains more variables than the first product like time series of Ocean Mass, Sea Level et Steric Sea Level change grids. It also includes additional variables that were not used for the Global ocean heat content calculation, such as the Global mean of ocean mass, Global mean sea level and Global mean steric sea level time series, but which may nevertheless be of interest to users. Users will therefore be able to find, among other things : - the regional map of the Ocean Heat Content trends (see image associated with this metadata sheet), - global ocean heat content change time series (representative of the globe within the extent of data availability), - earth energy imbalance time series (from global OHC filtered-out from signals lower than 3 years), - the uncertainties associated with these two datasets.

The CTOH computes and distributes specific, coastal along-track sea level anomalies (SLA) using its X-TRACK processor over 23 regions, for all precise altimeter missions : Topex/Jason-1/Jason-2/Jason-3 (+Topex Interleaved orbit (TPN)/Jason-1 Interleaved orbit (J1N)), SARAL/AltiKa, Envisat, Geosat Follow On The CTOH computes and distributes specific, coastal along-track sea level anomalies (SLA) using its X-TRACK processor for all precise altimeter missions : Topex/Poseidon (TP), Jason-1 (J1) , Jason-1 interleaved (J1N), Topex/Poseidon interleaved (TPN), Jason-2, Geosat Follow on (GFO) and Envisat. X-TRACK cover today all the coastal oceans, with 23 new regions.

Gridded multi-mission merged satellite significant wave height in Near-Real-Time. It merges along-track SWH data from the following missions: Jason-3, Sentinel-3A, Sentinel-3B, SARAL/AltiKa, Cryosat-2 and CFOSAT.

Biological parameters: Chlorophyll (several algorithms), Particulate Organic/Inorganic Carbon, Fluorescence…

Barystatic and manometric sea level changes represent the mass component of sea level changes at global and regional scales respectively. Barystatic and manometric sea level changes are estimated here using the satellite gravimetry measurements from the GRACE and GRACE-FO missions. Two products are distributed over the April 2002 to August 2022 period: - Barystatic sea level changes from satellite gravimetry with uncertainties at 1-sigma: monthly time series, - Manometric sea level changes from satellite gravimetry with uncertainties at 1-sigma: monthly grids with 1x1 degree.

Ssalto/Duacs multimission gridded sea surface heights products. From January 1993 to the last extension of the Delayed-time products, the long delayed-time dataset allows to compute statistical means of Maps of Sea Level Anomalies (MSLA) over different periods of time. Computed with respect to a twenty-year mean profile [1993-2012], and including the seasonal variability (no annual cycle is removed).

Eddies detected in Delayed-Time (DT) for the entire period [1993 - present]. Variables provided include day-by-day, and for one rotation type (Cyclonic/Anticyclonic) : - Center position (Longitude and latitude of the center of the best fit circle with the contour of maximum circum-average geostrophic speed); - Amplitude (|SSH(local_extremum) – SSH(outermost_contour)|); - Speed radius (Radius of the best fit circle with the contour of maximum circum-average geostrophic speed); - Speed average (Average geostrophic speed of the contour defining the speed radius); - Speed profile (Profile speed average values from effective contour inwards to smallest inner contour); - Effective contour (Largest contour of the detected eddy); - Speed contour (Contour of maximum circum-average geostrophic speed for the detected eddy).

Along-track altimetric GDR (Geophysical Data Record) products , geophysical and environmental corrections to apply. Available missions are: GFO, Topex/Poseidon, Envisat, Cryosat-2, Jason-1, Jason-2, Jason-3, Saral/AltiKa. Missions with several successive orbital types are treated in their entirety. Compared to the original version of the GDR files distributed by the CNES, ESA, NASA and ISRO agencies, the CTOH proposes new corrections and parameters in these files, which are to be applied to the initial altimetry measurement, according to user needs. Children metadata files are available for each mission.