In-Situ TAC Product: INSITU_GLO_PHY_TS_OA_MY_013_052. Issue 1.12.

Abstract

The document describes the Quality of the global gridded temperature and salinity fields released with the delayed mode temperature and salinity products and the associated error bars. The details of the product CORA: INSITU_GLO_PHY_TS_OA_MY_013_052 are given on table1. This product is based on the objective analysis of the temperature and salinity measurements taken from the global reprocessing product CORA (INSITU_GLO_PHY_TS_DISCRETE_MY_013_001), and linearly interpolated among 152 vertical levels. The Objective analysis is performed by the ISAS tool (based on the work by Gaillard et al. (2015) and developed by N. Kolodziejczyk and A. Prigent), based on the method developed by Bretherton et al. (1976). The method interpolates the temperature and salinity profiles in 3 dimensional fields, taking into account the correlation between nearby profiles, the bathymetry and the variability of the Rossby radius. The contribution of each profile to the temperature or the salinity fields is calculated by computing the innovation of the profiles taken relative to a first guess of the temperature and salinity fields. The accuracy of the method strongly depends on the spatial resolution of the initial temperature and salinity sampling. As a consequence, the results of the gridded fields might be close from the first guess in the poorly sampled zone, such as the Pacific Ocean or the deep ocean (depth<1000m) before the Argo program. To avoid misinterpretations of the gridded temperature and salinity fields, error bars fields that take into account the data coverage are produced. The error fields are a composite of estimated ocean variability in the low sampled zones and measurements error in the well sampled zones. As a consequence, the estimated error bars at a given point can vary from a few degree Celsius and PSU in the early period to few tenth of degree after the deployment of the ARGO program. CORA: Objective analysis in Delayed Mode - Temperature and Salinity in the Water Column (1960 - 2021) objective analysis in Delayed Mode