Oceans

Ocean Physics
At GISS we help develop, run and analyze standalone ocean model runs as well as coupled climate model runs to assess the impact and the feedbacks of ocean state and circulation to climate and climate change. Two different ocean models are being utilized, each of which represents a distinct class of ocean model discretizations and parameterizations, the Hybrid Coordinate Ocean Model and the Russell ocean model. Model simulations are evaluated against a wide range of observational datasets in order to reduce the model biases in the estimate of both the natural as well as the anthropogenic climate variability and its dependence on changes of the ocean thermohaline circulation and the ocean heat content. A suite of idealized and realistic tracers, such as ideal ocean age, ventilation, water mass tracers as well as CFC and carbon isotopes, have been in included in both ocean models to help elucidate model deficiencies and highlight processes that play a role in deep ocean mixing and eddy transport.

Ocean Carbon Cycle
At GISS we study the interactions of global biogeochemical cycles and the aquatic ecosystems, assess global environmental change and describe the implications for Earth’s climate, productivity, and natural resources. A research objective is to quantify global productivity, biomass, carbon fluxes and provide information about future changes in global carbon cycling in the aquatic ecosystems for use in ecological forecasting and as inputs for improved climate change projections. We specifically focus on biogeochemical modeling of the oceanic component of the carbon cycle and use satellite data both for model assessment and improvement. Carbon fluxes are prognostic and interactive with the rest of the coupled climate system, thereby enabling us to study climate interactions and feedbacks and the role of the ocean in natural as well anthropogenic climate change. The NASA Ocean Biogeochemical model (NBOM, Gregg et al, 2007; Romanou et al, 2013), which was developed at GSFC and is coupled with the GISS climate model, simulates the ocean carbon cycle using phytoplankton groups differentiation. NBOM has been recently retrofitted with capabilities such as alkalinity and nutrient and carbon riverine input, which will help us model ocean acidification and its impact on climate and ocean biodiversity and land-ocean exchanges.