Action #4: Upscale of Regional Data to a wider area

Objectives: The action aims to more realistically simulate air-sea CO2 fluxes using a 3D hydrodynamic/BGC/Carbonate ecosystem model (LTL, based on ERSEM). The model will be validated with CRETAN PSS in situ and satellite data via the enhancement of corresponding data acquisition (Action #1) to identify potential biases and necessary modifications (CT/AT initial fields and land-sea inputs, air-sea CO2 flux parameterization, etc). The final 3D model version will be used to evaluate the representativity (“footprint”) of the Cretan Sea solubility pump (air-sea exchanges and carbonate system) in the wider Eastern Mediterranean Sea, to promote the upscaling value of the Regional Data from CRETAN PSS.

Action Lead and other Partners (with contact persons): HCMR (Tsiaras), NIVA (King, Marty)

JS3 Platforms included: Core platforms: HCB fixed platform, E1-M3A fixed platform, Ferrybox, glider; Additional platforms: RV visits at HCB, RV visits at HCB & E1-M3A, Argo floats (see Action #1).

Other data sources: Satellite (SST, Chl-a from CMEMS or other sources).

Overall timetable of action: Feb 2022 to Aug 2022: Upgrading model with data collected (during

Dec 2020- Aug 2022 from Action #1)

Description of action: Key PSS features: Delivery of products with added value (upscaling). Collaboration element: linking with modelling and satellite community.

The Action includes: Data collection for model validation (input from Action #1). Comparison of simulations of Cretan Sea with wider eastern Mediterranean Sea. Update of the existing 3D physical-BGC-CO2 model (POM-ERSEM-HALTAFALL) to more realistically simulate air-sea CO2 exchanges, based on input from in-situ measurements of atmospheric and seawater pCO2, pH. The simulated pH, pCO2 will be also compared with derived data from algorithms based on satellite (SST, SSS, Chla) and in situ carbonate system-associated variables (links with actions i, ii).

Following Henson et al. (2016) methodology, the 3D model simulated CO2 will be analysed to identify the Cretan Sea (HCB station) footprint in the wider Eastern Mediterranean.

Best practices used or developed: NA

Data flows: Field data (see Action #1). Model data in POSEIDON database.

Data QC routines: NA

Data management issues: None expected

Expected results: improved understanding of air-sea CO2 fluxes, observing effort, and observing gaps.

Users of results: Scientists (chemists, modelers), ERICs (ICOS ERIC, EURO-ARGO ERIC), Databases (SOCAT)

Dissemination of results: First upgraded model results shown in D4.3. Dissemination to HCMR modelling team which will further disseminate them via modelling community workshops/conferences.

Links: enhanced cooperation with COPERNICUS via improved use of satellite products (T2.3), contribution to linking between scales by upscaling to a wider area (T2.4)