HIRETYCS: High Resolution 10 Year Climate Simulations

• Research unit: EU RFP
• Project number: 95.0640

Key words (English)

Global climate; climate modeling; general circulation models

Alternative project number (English)

EU project number: ENV4-CT95-0184

Research programs (English)

EU-programme: 4. Frame Research Programme - 3.1 Environment

Short description (English)

See abstract

Partners and International Organizations (English)

Météo-France, Hadley Centre, MPI, University of l'Aquila, INM, IRM and UCL, ADG Bologna, LGGE, SMHI

Abstract (English)

A comprehensive dataset of direct observations has been used to assess the surface energy fluxes in the GCMs participating in the HIRETYCS project. A number of shortcomings are identified in the models: The absorption of solar radiation at the surface is significantly overestimated in two of the models compared with more than 700 observation sites. A combination of the surface observations with collocated TOA measurements from satellites attributes these overestimates to a lack of absorption of solar radiation in the model atmospheres. This lack of absorption is also found in the cloud-free atmosphere, and is related to an underestimation of water vapour and aerosol absorption. In the longwave, evidence is presented that the longwave downward radiation is underestimated in the models, particularly at higher latitudes. This induces an artificially strong meridional gradient. The most apparent model bias in the non-radiative components of the surface energy balance is an overly small latent heat flux over continents in summer in two of the models, caused by an excessive summer dryness. All of the above biases are not notably reduced with higher resolution,indicating that the parameterization of model physics, rather than horizontal resolution, is the bottleneck on the way to a more reliable reproduction of the surface climate in GCMs.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 95.0640