August 24th, 2012 - Mixing of dust and NH3 observed globally over anthropogenic dust sources
Dust is one of the most abundant aerosols in the atmosphere, and by scattering and absorbing solar radiation, it affects climate. Anthropogenic dust is largely ignored in most current climate studies. We show how pervasive it is throughout the world, and that it is mostly associated with croplands.
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Dust is one of the most abundant aerosols in the atmosphere, and by scattering and absorbing solar radiation, it affects climate. In particular, anthropogenic dust is a significant source of radiative forcing on the climate system. Increasing numerical resolution of climate models provides an opportunity to create a realistic, high-resolution dust-source inventory. Read More…
August 10th, 2012 - Global calcite cycling constrained by sediment preservation controls
August 3rd, 2012 - Northern high latitude heat budget decomposition and transient warming
The future response of Atlantic meridional overturning circulation (AMOC) to increased carbon dioxide is known to be uncertain, with models showing 21st century weakening of 0 to 50%, according to the IPCC 4th report.
The authors examined the high northern latitude heat budgets of closely related climate models having large and small responses of AMOC to increased carbon dioxide. This paper shows that AMOC weakening is associated with the response of other important climate variables, so its uncertainty affects the projections for those variables as well. Read More…
Clouds and water vapor are among the difficult features of the atmosphere for global climate models to simulate because they are affected by physical processes that operate over very small areas compared to the weather patterns that the models explicitly calculate. The authors used satellite data to assess the representation of clouds and water vapor simulated by several climate models that will participate in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). Read More…
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…
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…