The Climate Space Ocean Surface Heat Flux (OSHF) project is part of ESA's Climate Space program. Within this program, ESA is expanding its portfolio on Essential Climate Variables (ECVs). The OSHF project will create a new climate data record (CDR) for total ocean surface heat flux, taking a novel approach that addresses the observation gaps and limitations of existing OSHF products. The main differences from previous data sets are an improved temporal and spatial representation of total OSHF across the world's oceans.

The OSHF is the total heat exchange between ocean and atmosphere and consists of four components: latent and sensible heat flux, and shortwave and longwave radiation. It has a direct influence on the energy and moisture balance of the atmosphere. It thermodynamically couples ocean and atmosphere on all scales. Furthermore, its variability is linked to large-scale fluctuations in weather conditions, which justifies the crucial importance of the OSHF as an ECV. Within the framework of the project, the OSHF is obtained from a combination of Earth observation and model data by deriving it from fundamental energy conservation laws relating to the heat content of the ocean.

Sea surface currents play a crucial role in calculating the OSHF, as they have a direct influence on how heat is distributed and exchanged at the boundary between ocean and atmosphere. DGFI-TUM contributes by carefully evaluating existing datasets on gridded ocean surface currents. Specifically, DGFI-TUM performs quality assessments by comparing ocean current models with in-situ data (e.g., surface velocity drifters) and conducting Lagrangian and spectral analyses on a global scale, while also focusing on specific regions of interest, such as western boundary currents or complex ocean current regions.

More information about the project and the collaboration partners can be found on the project website.