Assessing the Ability of Satellites to Resolve Sea Surface Temperature Variability – The ATOMIC Region

Presented at the GHRSST XXIII international science team meeting, 27 June-1 July 2022, online and in-person (Barcelona). #GHRSST23

Short abstract

Direct measurements of the SST from multiple platforms deployed during the Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC) field campaign are used to evaluate the ability of satellite products to accurately represent the spatial SST variability.  In situ SST measurements from the Research Vessel Ronald H. Brown, Saildrones, and drifters were collocated with five leading daily Level 4 SST analyses and two Level 3 single-sensor SST products during the period from January 1 to February 24, 2020.  The absolute accuracy of the satellite products was generally good with random errors on the order of 0.2 K or less, though most exhibited a small cool bias of ~0.1 K.  Sub-grid SST variability in the ATOMIC region was small (< 0.03 K) in relationship both to other regions and to uncertainties in the satellite products.  Despite their absolute accuracy, the satellite products were unable to provide a reliable representation of SST spatial gradients within the ATOMIC domain on the scale of their respective grid resolutions.  Correlations between satellite-derived and observed cell-to-cell SST differences were low, as the uncertainty in the satellite products dominated over small cell-to-cell variability in the region.  The products better represented the spatial SST variability on scales of 1° or more.  Simulations demonstrated that a satellite product precision of 0.05 K or less would be needed to successfully reproduce the observed SST spatial variability at the grid cell level, but this is challenging with current capabilities.  Independent observations from the Arctic showed greater variability and a relaxed accuracy requirement.