Characterization of subsurface Marine Heatwaves from ARMOR3D, a multi-observations statistical product.

The project “deteCtion and threAts of maRinE Heat waves – CAREHeat” (https://eo4society.esa.int/projects/careheat/, https://careheat.org/), funded by ESA in the framework of the Ocean Health initiative, aims at improving the current Marine Heatwaves (MHW) detection and characterization methodologies at the sea surface, at analysing MHW vertical propagation through the development of 4D temperature fields by using Machine Learning approaches, at providing a global atlas of MHW at the sea surface, at advancing the understanding of the physical processes involved in MHW development and at assessing the MHW impact on marine Ecosystems and Biogeochemistry.   

This presentation will focus on the analysis of a global 3D atlas of MWH produced from a multi-observations daily and 1/8° product (ARMOR3D - https://doi.org/10.48670/moi-00052) that merges satellite and in situ observations to reconstruct subsurface temperatures. An initial objective was to better characterize subsurface MHW, as they can have an impact on ecosystems. To meet this need, trends, patterns and vertical extent of 3D MHW have been analysed. A second objective was to estimate the observability of MHW in terms of sea surface height. For this, extreme events have been characterized in terms of heat content and thermosteric. The results will be commented in relation to current nadir altimeters and in relation to SWOT.