Presentation on theme: "The utility of long-term reconstructions with regional climate models Hans von Storch, Frauke Feser, Ralf Weisse and Lars Bärring The Third Workshop on."— Presentation transcript:
The utility of long-term reconstructions with regional climate models Hans von Storch, Frauke Feser, Ralf Weisse and Lars Bärring The Third Workshop on Regional Climate Modeling for Monsoon System (RCM) 17-21 February 2004, East-West Center, University of Hawaii, Honolulu,
The purpose of regional models is not to validate and improve them by making them more complex but to apply them in building of new knowledge about the real world.
Long term reconstruction Use of model SN-REMO (REMO + spectral nudging operating on wind above 850 hPa) – details, recall Feser‘s talk Forcing with NCEP re-analyses 1958- 2002 Gridding: 50 km Time step stored: 1 hourly Area: Europe Data freely available
Quality of reconstruction Is difficult to assess since specific high-resolution analyses hardly exist. Comparison with local data always questionable. Use of „integrating“ variables such as storm surges and wave heights yield favorable results. Wind data likely of high quality over sea – not over land.
Marcos Garcia Sotilla, 2003 Assimilated into NCEP (Atlantic) Not assimilated into NCEP (Ionic Sea) Wind speed at two bouys
20-year return values of wind speed, * based on daily 1992-97 data (color codes) Southern North Sea Extreme wind speeds * plus from station data in NL (numbers in black)
Insa Meinke, pers. comm. Accuracy of ISCCP estimates: about 10%
Applications 1.Assessment of changing storminess 2.Storm surges 3.Ocean wave conditions 4.Long-range pollution – examples: gasoline lead and benzapyren 5.Commercial applications – Wind energy planning and shipbuilding 6.Emergency planning – risk of coastal oil spills
Stormcount 1958-2001 Weisse, pers. comm. C/year t t
The Helgoland case of wave conditions in Oct 1998 Buoy at 54o 9’ N, 7o 52’ E, depth 22m (data available 1.10.1998 – 20.10 1998, every 3 hours) Radar (WAMOS) 54º10’N, 7º53’E, depth 7m (data available 9.10.1998-31.10.1998)
Model output vs radar and buoy measurements Lidia Gaslikova, pers. comm. Significant wave height Wave mean direction (coming from)
Comparison of significant wave height from ERS (Meteomer) and HIPOCAS hindcast for the Southern North Sea for 1993. Comparison with Satellite Data
model estimate Estimated lead depositions into the Baltic Sea, compared to analyses based on observational evidence Estimated transport in the Elbe river
Further Applications Assessment of oil drifts in case of coastal accidents Assessment of fatigue in ships and off-shore constructions (with FGS Flensburg) Planning of harbor constructions (Jade Port) Planning of off-shore wind energy (commercial) Assessment of coastal defense measures (ALR) Wave conditions in the Elbe estuary. Ulrich Callies, GKSS source
Conclusions Regional models can be used to reconstruct detailed weather in the past decades by downscaling global re-analyses. In particular information about marine wind can be used for assessing past developments and contemporary risk assessments.