To combat global warming, there have been suggestions to increase the albedo of (i.e. brighten) low-level marine clouds by deliberately injecting them with aerosols. Though such cloud seeding could mitigate global-mean temperature rise through the aerosol indirect effects, the full climate response to this geoengineering scheme is poorly understood. For example, one prior simulation of cloud seeding exhibited catastrophic rainfall decrease over the Amazon, while another showed moderate rainfall increase there. Read More…
GFDL Research Highlights
Using two fully coupled ocean-atmosphere GFDL models, CM2.1 and CM2.5 (a new high-resolution climate model based on CM2.1), the characteristics and sources of SST and precipitation biases associated with the Atlantic ITCZ were investigated and compared. Read More…
July 1st, 2012 - Projected Response of an Endangered Marine Turtle Population to Climate Change
Assessing the potential impacts of climate change on individual species and populations is essential for the stewardship of ecosystems and biodiversity. Marine turtles must lay eggs in sandy beaches and thus climate change can affect both their marine and terrestrial habitat. The population of critically endangered eastern Pacific leatherback turtles (Dermochelys coriacea) nesting on the northwest coast of Costa Rica has been studied in terms of its sensitivity to contemporary climate variability in the nesting beach and ocean. Read More…
Global mean sea level reflects the combined effects of the total mass of seawater and its global mean density. Adding to the net seawater mass, as from melting land ice, raises sea level. Likewise, lowering seawater density, as when water is heated, raises sea level through so-called steric effects. Read More…
June 1st, 2012 - Model Precipitation Bias over the Southwestern Equatorial Indian Ocean
This study investigated the spatio-temporal features of the serious positive precipitation bias over the southwestern equatorial Indian Ocean, found in most current coupled and uncoupled general circulation models, and its links with the large scale monsoon circulation. The study attempted to answer two questions: Is there a common identifiable mechanism forcing the local bias? Does the local bias have an influence on the continental simulated monsoon precipitation? Read More…
May 18th, 2012 - An Integrated “End-To-End” Model For Climate-Fish Interactions
Climate impacts on marine ecosystems arise from a combination of direct influences of physical climate on organisms (e.g., temperature effects on metabolic process) and indirect effects controlled by interactions with directly affected organisms. Indirect influences may originate with primary producers (i.e., phytoplankton) and propagate upward from the bottom of the food web or with higher trophic levels (i.e., fish) and propagate downward. Elucidating and predicting the response of living marine resources to climate and fishing pressure thus requires movement toward models that resolve interactions spanning physics to fish in an integrated way. Read More…
May 14th, 2012 - 21st Century Projections of North Atlantic Tropical Storms from CMIP5 Models
North Atlantic tropical storms (TS) are a major climate hazard to North America, and have exhibited variability and change on decadal timescales. Therefore, understanding and predicting future decadal TS activity on decadal timescales is central to NOAA’s mission and highly relevant to society. Read More…
May 4th, 2012 - Tropical Tropospheric-Only Responses to Absorbing Aerosols
An ongoing challenge in quantifying aerosols’ impact on the climate is determining an optimal way of calculating aerosols’ radiative forcing. For absorbing aerosols, in particular, studies have shown that a forcing calculation that does not include the tropospheric response to absorbing aerosol (instantaneous forcing) is a poor proxy for the change in global mean surface temperature caused by the aerosol. Read More…
April 27th, 2012 - Comparing Global Atmospheric Model Simulations of Tropical Convection
An intercomparison of global atmospheric model simulations of tropical convection has been presented and evaluated with available observations collected during the TWP-ICE field experiment. Short simulations initialized from the ECMWF analysis have been used to constrain model large-scale states and thus isolate model systematic biases originating from various physical parameterizations. With realistic thermodynamic and kinematic fields captured in various weather regimes (wet, dry, and break), model precipitation, cloud properties (LWC, IWC, cloud fraction), radiation, and vertical heating profiles respond accordingly in these regimes. Despite somewhat realistically simulated precipitation, there are substantial cloud property discrepancies among the models, which are mainly influenced by cloud and convective parameterizations. Read More…
High resolution global atmospheric models are becoming more credible tools for studying the effects of global warming on tropical cyclones, and we need to understand how those aspects of the models in which we have relatively low confidence affect the simulations. The goal of this research was to systematically explore and understand how some key parameters in this global atmospheric model affect the simulation of tropical cyclone frequency. Read More…