ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics Outline The coupling and feedback systems between the atmosphere and ocean that is driving energy transfer and climate change. Concepts of surface exchange of heat and greenhouse gas transfer between atmosphere / land / ocean / biosphere. The role of clouds in the climate system, including their effect on radiation and energy transfer. How clouds are parameterised in climate models and the very large uncertainties in their effect on climate change. Changing aspects of water mass formation and its implication on the oceans thermohaline circulation and climate. Cause and consequence of sea ice recession on the atmosphere and global sea levels.
ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics Suggested Reading IPCC Third Assessment Report - Climate Change 2001: The Scientific Basis. 2001, Cambridge University Press. [ available free online at http://www.grida.no/climate/ipcc_tar/wg1/index.htm ]http://www.grida.no/climate/ipcc_tar/wg1/index.htm Global warming. John Houghton, Rep. Prog. Phys. 68 (2005) 1343–1403. Online at http://stacks.iop.org/RoPP/68/1343http://stacks.iop.org/RoPP/68/1343 TEXT BOOKS: The Physics of Atmospheres. John Houghton, 2002, Cambridge University Press. Boundary Layer Meteorology. Roland Stull,1988, Kluwer Academic Press. The Atmosphere and Ocean: A Physical Introduction. Neil Wells, 1997, Wiley. Human Impacts on Weather and Climate. William Cotton & Roger Pielke, 1995, Cambridge University Press.
ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics Online Resources Intergovernmental Panel on Climate Change: http://www.ipcc.ch/index.html http://www.ipcc.ch/index.html Real Climate – comment on climate issues by climate scientists. http://www.realclimate.org/http://www.realclimate.org/ SOLAS program – ocean-atmosphere exchange & climate processes: http://www.uea.ac.uk/env/solas/http://www.uea.ac.uk/env/solas/ US National Snow and Ice Data Centre: http://nsidc.org/http://nsidc.org/
ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics Climate & Climate Change Climate change is often considered synonymous with global warming – a result of human activities. This is an over- simplification. Climate processes are many, and interact in complex ways, not always obvious. Feedbacks between different processes may amplify or inhibit the first order effects.
ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics Climate System Atmosphere –Includes gaseous atmosphere, clouds, aerosols Hydrosphere –Oceans, rivers, precipitation Cryosphere –Polar icecaps, ice sheets, glaciers, snow-covered landmass, permafrost Land surface –Surface type Biosphere –Plants, animals, plankton,… The climate systems consists of 5 major components: External forcing: solar radiation, volcanic activity (addition of aerosols & gases to atmosphere), human activity.
ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics Sea surface temperature anomalies relative to 1961-1990 mean for North Atlantic (tropical: blue, extra-tropical : red, black lines are 10-year running averages). (Trenberth, 2005: Uncertainty in Hurricanes and Global Warming. Science, vol 208, doi: 10.1126/science.1112551)
ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics CO 2 concentration (grey line) and mean polar temperature difference from now (Black line) from Vostock ice core measurements. CO 2 concentration estimates projected forward to 2100. (Houghton, Rep. Prog. Phys. 68 (2005) 1343–1403)
ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics Northern Hemisphere ice extent is decreasing at a rate of -2.7 ± 0.5% per decade. The rate of decline in summer (-4.9 ± 1.5%) is considerably greater than that for winter (-1.8 ± 0.6%)
2002 : record minimum in Arctic sea ice concentration
ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics Change of climate state Changes to either the mean or variance in climate state both lead to increased occurrence of extreme conditions.
ENVI3410: Coupled Ocean & Atmsophere Climate Dynamics There is substantial evidence that climate is changing: increasing globally averaged temperature, decreasing ice extent, changing precipitation patterns,… There is also substantial evidence that human activity has increased the levels of ‘greenhouse’ gases in the atmosphere. There are strong correlations between greenhouse gas concentrations and temperature, and basic physics suggests higher concentrations should lead to warming, but… –How can we be sure what the real relationships are between our activities and climate?