Geophysical Fluid Dynamics Laboratory

About: Geophysical Fluid Dynamics Laboratory is a facility organization based out in Princeton, New Jersey, United States. It is known for research contribution in the topics: Climate model & Climate change. The organization has 525 authors who have published 2432 publications receiving 264545 citations. The organization is also known as: GFDL.

On the Climatic Impact of Ocean Circulation

Abstract: Integrations of coupled climate models with mixed-layer and fixed-current ocean components are used to explore the climatic response to varying magnitudes of ocean circulation. Four mixed-layer ocean experiments without ocean heat transports are performed using two different atmosphere‐land components—the new GFDL AM2 and the GFDL Manabe Climate Model (MCM)—and two different sea ice components, one dynamic and one thermodynamic. Both experiments employing the dynamic sea ice component develop unstable growth of sea ice while the experiments with a thermodynamic sea ice component develop very large but stable ice covers. The global cooling ranges from modest to extreme in the four experiments. Using the fixed-current climate model, a trio of 100-yr integrations are made with control currents from a GFDL R30 ocean simulation, same currents reduced by 50%, and same currents increased by 50%. This suite is performed with two coupled models again employing the two atmosphere‐land components, AM2 and MCM, for a total of six experiments. Both models show a large sensitivity of the sea ice extent to the magnitude of currents with increased currents reducing the extent and warming the high latitudes. Low cloud cover also responds to circulation changes in both models but in the opposite sense. In the AM2-based model, low cloudiness decreases as ocean circulation increases, reinforcing the sea ice changes in reducing the planetary reflectivity, and warming the climate. This cloudiness change is associated with a reduction in lower-atmospheric stability over the ocean. Because the AM2-based model is able to simulate the observed seasonal low cloud‐stability relationship and the changes in these quantities with altered ocean circulation are consistent with this relationship, the AM2 interpretation of the cloud changes is favored.

Climate Variability and Radiocarbon in the CM2Mc Earth System Model

Abstract: The distribution of radiocarbon (14C) in the ocean and atmosphere has fluctuated on time scales ranging from seasons to millennia. It is thought that these fluctuations partly reflect variability in the climate system, offering a rich potential source of information to help understand mechanisms of past climate change. Here, a long simulation with a new, coupled model is used to explore the mechanisms that redistribute 14C within the earth system on interannual to centennial time scales. The model, the Geophysical Fluid Dynamics Laboratory Climate Model version 2 (GFDL CM2) with Modular Ocean Model version 4p1(MOM4p1) at coarse-resolution (CM2Mc), is a lower-resolution version of the Geophysical Fluid Dynamics Laboratory’s CM2M model, uses no flux adjustments, and is run here with a simple prognostic ocean biogeochemistry model including 14C. The atmospheric 14C and radiative boundary conditions are held constant so that the oceanic distribution of 14C is only a function of internal climate variab...

The General Circulation Model Response to a North Pacific SST Anomaly: Dependence on Time Scale and Pattern Polarity

Abstract: A general circulation model was integrated with perpetual January conditions and prescribed sea surface temperature (SST) anomalies in the North Pacific. A characteristic pattern with a warm region centered northeast of Hawaii and a cold region along the western seaboard of North America was alternately added to and subtracted from the climatological SST field. Long 1350-day runs, as well as short 180-day runs, each starting from different initial conditions, were performed. The results were compared to a control integration with climatological SSTs. The model's quasi-stationary response does not exhibit a simple linear relationship with the polarity of the prescribed SST anomaly. In the short runs with a negative SST anomaly over the central ocean, a large negative height anomaly, with an equivalent barotropic vertical structure, occurs over the Gulf of Alaska. For the same SST forcing, the long run yields a different response pattern in which an anomalous high prevails over northern Canada and ...