Susanne Pfeifer

Performance of a multi-RCM ensemble for South Eastern South America

The ability of four regional climate models to reproduce the present-day South American climate is examined with emphasis on La Plata Basin. Models were integrated for the period 1991–2000 with initial and lateral boundary conditions from ERA-40 Reanalysis. The ensemble sea level pressure, maximum and minimum temperatures and precipitation are evaluated in terms of seasonal means and extreme indices based on a percentile approach. Dispersion among the individual models and uncertainties when comparing the ensemble mean with different climatologies are also discussed. The ensemble mean is warmer than the observations in South Eastern South America (SESA), especially for minimum winter temperatures with errors increasing in magnitude towards the tails of the distributions. The ensemble mean reproduces the broad spatial pattern of precipitation, but overestimates the convective precipitation in the tropics and the orographic precipitation along the Andes and over the Brazilian Highlands, and underestimates the precipitation near the monsoon core region. The models overestimate the number of wet days and underestimate the daily intensity of rainfall for both seasons suggesting a premature triggering of convection. The skill of models to simulate the intensity of convective precipitation in summer in SESA and the variability associated with heavy precipitation events (the upper quartile daily precipitation) is far from satisfactory. Owing to the sparseness of the observing network, ensemble and observations uncertainties in seasonal means are comparable for some regions and seasons.

Changes of the Arctic climate under the SRES B2 scenario conditions

In the framework of the Sonderforschungsbereich 512 (Cyclones and the North Atlantic climate system), regional climate simulations of a control period (nominally 1970-1979) and future Arctic climate (2070-2079) have been conducted with the regional climate model REMO. The regional simulation has been initialised and driven by results of the global climate model ECHAM4 on the basis of the SRES B2 scenario. The model domain encloses the entire Arctic region. Compared to the interdecadal variability of max. 1 K for temperature and max. 25 mm for annual mean precipitation deduced from results of the global simulations, the mean temperature increase of 5.5 K between the two periods derived from the regional simulation and the increase in annual mean precipitation of 80 mm can be interpreted as climate change signal. The differences between the global and the regional simulation do not show up in spatial and temporal mean values but in the broader distribution of the precipitation intensities in the regional model as well as in smaller spatial variabilities for the global simulation especially over land areas.

Erratum to: EURO-CORDEX: new high-resolution climate change projections for European impact research

Daniela Jacob • Juliane Petersen • Bastian Eggert • Antoinette Alias • Ole Bossing Christensen • Laurens M. Bouwer • Alain Braun • Augustin Colette • Michel Deque • Goran Georgievski • Elena Georgopoulou • Andreas Gobiet • Laurent Menut • Grigory Nikulin • Andreas Haensler • Nils Hempelmann • Colin Jones • Klaus Keuler • Sari Kovats • Nico Kroner • Sven Kotlarski • Arne Kriegsmann • Eric Martin • Erik van Meijgaard • Christopher Moseley • Susanne Pfeifer • Swantje Preuschmann • Christine Radermacher • Kai Radtke • Diana Rechid • Mark Rounsevell • Patrick Samuelsson • Samuel Somot • Jean-Francois Soussana • Claas Teichmann • Riccardo Valentini • Robert Vautard • Bjorn Weber • Pascal Yiou