ENSO teleconnections in projections of future climate in ECHAM5/MPI-OM

• Published in: Climate dynamics Vol. 31; no. 5; pp. 533 - 549
• Main Authors: Müller, W. A, Roeckner, E
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.10.2008; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Atmospheric sciences; Carbon dioxide; Climate change; Climate models; Climatology; Climatology. Bioclimatology. Climate change; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; El Nino; Exact sciences and technology; External geophysics; Geophysics/Geodesy; Greenhouse gases; Intergovernmental Panel on Climate Change; Marine; Meteorology; Ocean-atmosphere interaction; Oceanography; Physics of the oceans; Sea surface temperature; Sea-air exchange processes; Southern Oscillation; Teleconnections; Wind; Atlantic Ocean; Equatorial Pacific; Northeast Atlantic; Pacific Ocean; North Atlantic; European Atlantic; East Pacific; AN, North Atlantic; IE, East Pacific; IN, North Pacific; I, Pacific; AN, North Atlantic, North Atlantic Oscillation; North America; IS, Tropical Pacific; Pacific North America; North Atlantic European; North Atlantic Oscillation; Zonal Wind; Zonal Wind Anomaly; Teleconnection; General circulation models; climate warming; climate variability; Climate models; Hadley cell; ocean-atmosphere interaction; Forecast model; North America; Dynamical climatology; Ocean-atmosphere model; Atmospheric dynamics; Walker circulation; El Nino; global change; Southern oscillation; atmospheric circulation; climate change; Standing wave
• ISSN: 0930-7575; 1432-0894
• DOI: 10.1007/s00382-007-0357-3

The teleconnections of the El Niño/Southern Oscillation (ENSO) in future climate projections are investigated using results of the coupled climate model ECHAM5/MPI-OM. For this, the IPCC SRES scenario A1B and a quadrupled CO₂ simulation are considered. It is found that changes of the mean state in the tropical Pacific are likely to condition ENSO teleconnections in the Pacific North America (PNA) region and in the North Atlantic European (NAE) region. With increasing greenhouse gas emissions the changes of the mean states in the tropical and sub-tropical Pacific are El Niño-like in this particular model. Sea surface temperatures in the tropical Pacific are increased predominantly in its eastern part and redistribute the precipitation further eastward. The dynamical response of the atmosphere is such that the equatorial east-west (Walker) circulation and the eastern Pacific inverse Hadley circulation are decreased. Over the subtropical East Pacific and North Atlantic the 200 hPa westerly wind is substantially increased. Composite maps of different climate parameters for positive and negative ENSO events are used to reveal changes of the ENSO teleconnections. Mean sea level pressure and upper tropospheric zonal winds indicate an eastward shift of the well-known teleconnection patterns in the PNA region and an increasing North Atlantic oscillation (NAO) like response over the NAE region. Surface temperature and precipitation underline this effect, particularly over the North Pacific and the central North Atlantic. Moreover, in the NAE region the 200 hPa westerly wind is increasingly related to the stationary wave activity. Here the stationary waves appear NAO-like.