COST: European Cooperation in Science and Technology
COST 727 Action
Measuring and forecasting atmospheric icing on structures
Alain Heimo Meteotest, Switzerland MC Chairman/COST727
COST is one of the longest-running instruments supporting co-operation among scientists and researchers across Europe. TOPICS - Atmospheric icing • Why is icing a problem – Socio-economic importance • Meteorological measurements • Recent activities - COST-727 - Objectives - Organisation and members - Latest results - Measurements (WG2) - Modeling (WG1) - Deliverables - Future activities Atmospheric icing: Why is it a problem?
Atmospheric icing causes severe financial losses and reduces security and human safety :
- Power transmission … Spain 2002 Germany 2005
Norway 1961 Atmospheric icing: Why is it a problem?
Atmospheric icing causes severe financial losses and reduces security and human safety :
- Power transmission - Icing of structures (e.g.:TV- and telecommunication towers, ski-lifts) ... Design of loads, safety, operational stops..
On TV-towers the ice load may be several tens of tons. Atmospheric icing: Why is it a problem?
Atmospheric icing causes severe financial losses and reduces security and human safety :
- Power transmission - Icing of structures (e.g.:TV- and telecommunication towers, ski- lifts) - Telephone lines, Forest economy... Ice load + high winds ! Atmospheric icing: Why is it a problem?
Atmospheric icing causes severe financial losses and reduces security and human safety :
- Power transmission - Icing of structures (e.g.:TV- and telecommunication towers, ski- lifts) - Power lines, Telephone lines, Forest economy - Wind Power production ... - Uncertainities in prediction of production - Additional loads /design - Safety: falling ice, operational safety - Reduction in power production due to: - reduced lift - shut-down - mechanical failures - iced wind sensors Atmospheric icing: Why is it a problem?
Atmospheric icing causes severe financial losses and reduces security and human safety :
- Power transmission - Icing of structures (e.g.:TV- and telecommunication towers, ski- lifts) - Power lines, Telephone lines, Forest economy - Wind Power production - Aviation ... Icing at airports and in the air
No icing
Icing
source: http://meted.ucar.edu Atmospheric icing: Why is it a problem?
Atmospheric icing causes severe financial losses and reduces security and human safety :
- Power transmission - Icing of structures (e.g.:TV- and telecommunication towers, ski- lifts) - Power lines, Telephone lines, Forest economy - Wind Power production - Aviation - Meteorology Meteorological measurements EUMETNET Severe Weather Sensors SWS II experiment
Säntis Station, Switzerland Atmospheric icing: former activities
Status before COST-Action 727:
1) Icing measurements performed in many countries in Europe since the 1930’s, however with only limited standards for instruments and data acquisitions. 2) Measurements • No reliable ice detectors available. • The WMO/CIMO guidelines for measurements of icing do not exist yet: specifications required. 3) Modeling, mapping • Atmospheric icing (rate, cumulative ammount, duration, etc.) is not forecasted for low altitudes (ABL) nor measured by NMHSs. • Input data (LWC, droplet size,..) for calculations of ice accretion not available. • Coarse icing climatology for Europe (based on indirect observations) Atmospheric icing: former activities
WMO/CIMO Wind Instrument Intercomparison Mont Aigoual, France, 1992-1993
Organized by France, Switzerland & WMO
Participating countries: 11 Jungfraujoch, Switzerland Instruments tested: 26 Conclusions from the final report:
-… The formation of ice makes almost all the calculated parameters incoherent. - … We have not been able to characterize the icing phenomena from ice detectors. - … It appears difficult to be both “accurate” and rugged for severe icing. Atmospheric icing: former activities
EUMETNET SWS-II (2000-2003)
Goal: Acquisition of meteorological data under icing conditions in Finland (Luosto), France (Mt. Aigoual) and Switzerland (Säntis)
Measurement period: 1.10.2001 to 30.4.2002 Luosto, finland
Conclusions and recommendations:
- …. Already during the installation and test period proceeding the experiment, it was quickly recognized that the lack of adequate instruments for the characterization of ice accretion would represent a serious drawback for the whole experiment.
- … it is important that more care is given within the meteorological community to produce accurate measurements under harsh conditions and to promote measurements of icing. COST 727 Main Objectives:
• to develop the understanding of icing (especially in-cloud icing) and freezing rain in the atmospheric boundary layer (ABL)
• to produce information on distribution of icing over Europe
• to improve the potential to observe icing monitor icing forecast icing Participating countries
Parties: list of countries and date of acceptance
Country Date Country Date Country Date Country Date
Austria 29/01/2004 Bulgaria 10/03/2004 Czech 20/04/20 Finland 29/01/2004 Republic 04
Germany 29/01/2004 Hungary 29/01/2004 Norway 29/01/20 Slovakia 05/04/2005 04
Spain 15/06/2004 Sweden 22/06/2004 Switzerland 15/06/20 United 15/06/2004 04 Kingdom
Total: 12
Non-COST Participant: Japan (Kanagawa Institute of Technology) Phase 2: Research and Development
COST 727 MEASURING AND FORECASTING ATMOSPHERIC ICING ON STRUCTURES
MC Chair: Dr. A. Heimo (CH) Vice Chair: Dr. D. Nikolov(BU)
WG 1 WG 2 Ice loads and forecasting Icing measurements
Chair: Dr. L. Makkonen VTT (FIN) Chair: S. Fikke, Consultant (N) Vice Chair: J. Hosek (CZ) Vice Chair: G. Ronsten, WindREN AB (S) 18 members 12 members Objectives:
To develop scientific understanding of icing processes together with modeling and forecasting of icing.
Measurements:
. To compile existing sources of icing data in Europe . To harmonize ongoing measurement programs in Europe . To fulfill the WMO/CIMO request to provide guidance for performing measurements under harsh icing conditions. . To promote the development of robust, rugged icing detectors to be deployed at automatic meteorological stations as well as at other sites where icing effects may be critical. Simple sensors delivering a yes/no information are needed as well as more sophisticated instruments yielding values of ice thickness/weight, types of ice.
Modelling:
. To develop numerical meteorological models for icing studies with improved icing parameterizations and verification of icing models with ground-truth data. . To perform climatological icing studies and mapping of icing severity COST-727 Action
Phase I (2005-2006): State of the Art report
The main scope of this phase was to create an inventory of earlier and current activities on icing measurements, data resources and instrument testing. The emphasis is on activities within the signatory countries, however some additional information from other countries like Russia and Canada is included as well. Measurements of icing
Achieved during the last 2 years:
-Based on preliminary measurements, selection of 2 « reference » sensors for the detection of ice accretion (Goodrich 0847LH1) and for the measurement of ice loads (Combitech Mk I)
Principle: weighting of ice Principle: ultrasonic resonance + designed according to ISO 12494 definition + promising results + operational from the from earlier studies beginning + promising results - difficult to get it from manufacturer - design improvements (military regulations) - only little needed (e.g. oscillations) measurement data available Measurements of icing (WG2)
Achieved during the last 2 years:
- Based on preliminary measurements, selection of 2 « reference » sensors for the detection of ice accretion (Goodrich 0847LH1) and for the measurement of ice loads (Combitech Mk I) - Calibration of the « reference » instruments in a dedicated icing wind tunnel facility (Kanagawa Institute, Tokyo, Japan) Icing wind tunnel test
in Cryospheric Environment Simulator at in Kanagawa Institute of Technology Shinjo Branch of National Research Institute for Earth Science and Disaster Prevention < 20m/s (with a larger test section) < 20m/s (1m by 1m test section) < 100m/s (in a smaller test section) > -25 deg. Cel. > -25 deg. Cel. Sprayers not installed all the time Measurements of icing (WG2)
Achieved during the last 2 years:
-Based on preliminary measurements, selection of 2 « reference » sensors for the detection of ice accretion (Goodrich 0847LH1) and for the measurement of ice loads (Combitech Mk I) - Calibration of the « reference » instruments in a dedicated icing wind tunnel facility (Kanagawa Institute, Tokyo, Japan) - Installation and operation of 6 test stations in Europe equipped with the Combitech Mk I (2007:2008) and the Goodrich 0847LH1 (2008): Luosto (Finland), Sveg (Sweden), Zinnwald (Germany), Deadwater Fell (United Kingdom), Studnice (Czech Republic) and Guetsch (Switzerland) European test stations Switzerland (Guetsch test station)
Czech Republic (Studnice)
Germany (Zinnwald) Luosto fell, Finland
Åre, Sweden
Deadwater Fell, UK Measurements of icing (WG2)
Achieved during the last 2 years:
-Based on preliminary measurements, selection of 2 « reference » sensors for the detection of ice accretion (Goodrich 0847LH1) and for the measurement of ice loads (Combitech Mk I) - Calibration of the « reference » instruments in a dedicated icing wind tunnel facility (Kanagawa Institute, Tokyo, Japan) - Installation and operation of 6 test stations in Europe equipped with the Combitech Mk I (2007:2008) and the Goodrich 0847LH1 (2008): Luosto (Finland), Sveg (Sweden), Zinnwald (Germany), Deadwater Fell (United Kingdom), Studnice (Czech Republic) and Guetsch (Switzerland) - Setup of the first European Icing Dataset containing all meteorological parameters necessary for icing modeling and simulation -> winter 2007-2008: selection of 3 major icing events for each station Modelling icing of structures (WG1)
• The theoretical basic knowledge is presently available, based on the ISO 12494 standards (Makkonen formula) and new cloud microphysics schemes built in the WRF model code
• Verification data are now available and standardized for sites located all around Europe. Unfortunately more data (winters) are needed.
• Preliminary results show that the current version of the WRF model is able to perform very accurate simulations of icing events at all test stations in Europe (especially for the collapse of a measurement tower in Switzerland)
• Measured site information about the Liquid Water content and Droplet Size Distribution are still missing
• Tentative simulation runs of wet snow accretion and freezing rain events have been started Numerical modeling of ice accretion
• WRF is a modern mesoscale, non-hydrostatic numerical weather prediction model developed mainly by NCAR, NOAA and NCEP (USA) designed for mesoscale and high resolution forecasts.
• WRF has the advantage of a very sophisticated calculation of clouds and precipitation.
• Applications from Large Eddy Simulations: Δx = 100m to regional climate simulations: Δx = 100km.
• WRF is meant to gradually replace its predecessor, MM5. WRF simulation
Schwyberg (Switzerland) November 2007 Iceload kg/m – Schwyberg Nov - 07 Tower collapse at Schwyberg, Switzerland
Data acquisition failure
Ice load and strong winds -> tower collapse Relationship with WMO/CIMO
CIMO Expert Team on Surface Technology and Measurement Techniques (ETST&MT) Geneva, Switzerland, September 2008
“ETST&MT recommended to the Management Group to encourage NMHSs to maintain those stations after completion of the action.”
“ETST&MT agreed that CIMO should closely collaborate with COST on this topic and would welcome the joint WMO/COST publication of the COST 727 Report as an IOM Report. This report would provide important information to WMO Members and would be a good base for the further development of guidelines on icing to be later published in the CIMO Guide.”
“ETST&MT recommended that a new chapter on Extreme Weather should be published in the CIMO Guide. ..The part of this chapter on icing should be mainly based on the findings of the COST 727 action.” Activities until end of Action • Measurements o Continuous operation of the 6 test stations equipped with the 2 “reference” instruments o Upgrade of the present instruments together with the manufacturer o Extend dataset with the winter 2008-2009 measurements • Modeling o Upgrade WRF model with updated microphysics (PhD) o Perform simulations based on the EID o Perform sensitivity studies with LWC and MVD • Final Workshop will be held together with the International Workshop on Atmospheric Icing on Structures IWAIS XIII in Andermatt (Switzerland) , 8-11.9.2009 (www.IWAIS2009.ch) Further details in the next presentation (Cattin) and on poster P5 (Nygaard)
Thank you for your attention !