MERCURE: Modelling European regional climate - understanding and reducing errors

• Research unit: EU RFP
• Project number: 97.0080

Key words (English)

Regional climate modelling; climate processes; climate preciction; hydrological cycle; heavy precipitation; Europe; Alps

Alternative project number (English)

EU project number: ENV4-CT97-0485

Research programs (English)

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

Short description (English)

See abstract

Partners and International Organizations (English)

Coordinator: UKMO Hadley Centre for Climate Prediction (UK)

Abstract (English)

The Climate High Resolution Model (CHRM) in use at IAC-ETH for Regional Climate Modeling (RCM) studies (MERCURE, NCCR, PRUDENCE projects) has undergone several important changes in the last year, meant to allow it to complete multi-year simulations while retaining sustainable water and energy cycles. This represents a departure from the weather version of the model, which is not addressing these conservation aspects and relies on continuous re-initialization through soil data (temperature and soil moisture) assimilation in order to guarantee forecast quality.

The principal physical parameterization improvements have come in the area of soil water vertical transfer, which is now occurring at normal rates, permitting normal winter re-charge of the root zone and correcting a summer ET bias of 40 W/m2 (monthly mean) over most of central and southern Europe. The other important changes have been introduced in the area of cloud-radiation interactions, permitting to correct a surface (short wave) negative bias of 40 W/m2 (monthly mean) at the peak of summer. Surface temperatures, which were kept artificially high in the weather version through artificial soil water depletion (resulting however in severe summer warm biases over certain regions) have initially suffered (with the creation of a 2 K negative bias) from the more accurate summer ET rates, but have been improved after the corrections in radiation, due to a better representation of the surface energy balance.

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: 97.0080