CESM Project
Climate Highlights
Study may answer longstanding questions about Little Ice Age. The study, which used analyses of patterns of dead vegetation, ice and sediment core data, and powerful computer climate models, provides new evidence in a longstanding scientific debate over the onset of the Little Ice Age. [highlight]
Ozone recovery and greenhouse gases in the Southern Hemisphere. A new study in Geophysical Research Letters looks at how the anticipated recovery of the ozone hole over Antarctica and simultaneous increase in greenhouse gas concentrations will combine to affect weather and climate in the Southern Hemisphere. It concludes that over the coming half century, ozone recovery will result in a nearly complete cancellation of the effects of increased greenhouse gases on atmospheric circulation. [highlight]
Publication News
Special collections of the Journal of Climate describe numerous aspects of the fourth version of the Community Climate System Model (CCSM4) and the Community Earth System Model (CESM1) are being prepared. [Early on-line release of accepted manuscripts]
The Community Climate System Model Version 4. The fourth version of the Community Climate System Model (CCSM4) was recently completed and released to the climate community. This paper describes developments to all CCSM components, and documents fully coupled pre-industrial control runs compared to the previous version, CCSM3. Using the standard atmosphere and land resolution of 1° results in the sea surface temperature biases in the major upwelling regions being comparable to the 1.4° resolution CCSM3. Two changes to the deep convection scheme in the atmosphere component result in CCSM4 producing El Nino/Southern Oscillation variability with a much more realistic frequency distribution than CCSM3, although the amplitude is too large compared to observations. They also improve the Madden-Julian Oscillation, and the frequency distribution of tropical precipitation. [article]
Effect of the potential melting of the Greenland Ice Sheet on the Meridional Overturning Circulation and global climate in the future. Multiple recent observations indicate an accelerated mass loss of the Greenland Ice Sheet since the mid-1990s. This increased ice sheet mass loss might be an evidence of global warming and could be related to elevated atmospheric greenhouse gas concentrations. Here, we use the National Center for Atmospheric Research Community Climate System Model version 3 to assess the potential influence of a shrinking Greenland Ice Sheet on the Atlantic Meridional Overturning Circulation (MOC), the surface climate, and sea level in the next two centuries under the IPCC A1B scenario with prescribed rates of Greenland Ice Sheet melting. [article]
The contribution of snow condition trends to future ground climate. Global climate models predict that terrestrial northern high-latitude snow conditions will change substantially over the twenty-first century. Results from a Community Climate System Model simulation of twentieth and twenty-first (SRES A1B scenario) century climate show increased winter snowfall (+10–40%), altered maximum snow depth (−5 ± 6 cm), and a shortened snow-season (−14 ± 7 days in spring, +20 ± 9 days in autumn). By conducting a series of prescribed snow experiments with the Community Land Model, we isolate how trends in snowfall, snow depth, and snow-season length affect soil temperature trends. [article]
CESM Information
The Community Earth System Model (CESM) is a fully-coupled, global climate model that provides state-of-the-art computer simulations of the Earth's past, present, and future climate states.
Upcoming Meetings
17th Annual CESM Workshop
The 17th Annual CESM Workshop will held at The Village at Breckenridge, Breckenridge, CO, 18 - 21 June 2012. [event details] [agenda] [webcasts] [questions]
Community Earth System Modeling Tutorial
30 July - 03 August 2012, National Center for Atmospheric Research, Boulder, CO [announcement] [application]
CESM Distinguished Achievement
David Williamson is the recipient of the 2011 CESM Distinguished Achievement Award. [more]
CESM in the News
Climate scientists compute in concert.
Keywords: CESM, CCSM, SEACISM [article]
Model provides successful seasonal forecast for the fate of Arctic sea ice.
Staff: Marika Holland [UW Press Release] [article]
Deep oceans can mask global warming for decade-long periods.
Staff: Gerald Meehl and Kevin Trenberth [UCAR Press Release] [related] [related] [related] [related] [related] [related] [related] [related]
New computer model advances climate change research
Staff: James Hurrell [WCRP] [UCAR press release] [NSF press release] [USA Today] [related] [related] [related]