NWP models Icelandic Met. Ofce - June 2018 Bolli Pálmason
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NWP models
@
Icelandic Met. Ofce
14. June 2018
Bolli Pálmason
Two main models used at IMO
●
Global model
●
Horizontal resolution of
approx. 9 km
●
Vertical resolution 137
levels (top at 0.01 hPa)
●
Medium range 10 day
forecast
HARMONIE
HARMONIE-AROME
Limited Area Model (LAM)
ECMWF progress until 2010
ECMWF pioneers in 4D-Var data assimilation
ECMWF Ensemble forecasts The ECMWF Ensemble Prediction System (EPS) provides a practical tool for estimating how small diferences could afect the forecast. The ECMWF weather prediction model is run 51 times from slightly diferent initial conditions. To take into account the efect of uncertainties in the model formulation, each forecast is made using slightly diferent model equations.
Sandy visits New York in autumn 2012
ECMWF forecasts Sandy to come ashore
IMO became ECMWF full member in 2011
HIRLAM/ALADIN: Cooperation of countries in Europe
Limited Area NWP model domains
HARMONIE-AROME: AROME and SURFEX
AROME:
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Non-hydrostatic convection-permitting
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Horizontal resolution of 2.5 km
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65 vertical model levels, top at 10 hPa
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Lowest ML at ca. 12 m over ground
SURFEX:
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Surface and soil processes
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Stand alone or coupled to atmosphere
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Interaction Soil-Biosphere-Atmosphere
(ISBA) force restore
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Tiles: sea, lake, urban and nature (soil
and vegetation)
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Coupled to AROME
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Atmosheric forcings from lowest
model level (12m)
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Radiative properties and surface
fuxes back to AROME
DOI: http://dx.doi.org/10.1175/MWR-D-16-0417.1HARMONIE @ IMO – Main milestones
●
First semi-operational run in 2011 - Cold start each cycle (ECMWF glaciers)
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Surface DA in autumn 2012 - Seasonal snow accumulation and melt
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Tuning of 10 m windspeeds 2013 - Big improvements in scores
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Fix T2m cold bias over lakes 2013 - Obvious errors removed
●
Physiography database (PGD) upgrade starts in autumn 2014 in
collaboration with Agricultural University of Iceland (best vegetation and
soil databases)
●
Major operational upgrade autumn 2015:
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Bigger domain - fx spin-up problems of convective precipitation over sea
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Upgraded PGD - land cover / sand & clay / topography
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Snow on glaciers – start snow-year with 10 tons of snow on top of glaciers
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Cycle 38 of HARMONIE-AROME
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Became the ICRA-2016 setupHARMONIE setup for Iceland
IMO operational HARMONIE model
Version: 38h1.2 running on ECMWF cca/ccb
Domain: 500x480x65. Top at 10 hPa
Horizontal res.: 2.5 km. Coupled hourly with EC-HRES
Dynamics: Non-hydrostatic. Physics: Arome
Surface DA: Canari + OI_Main. Around 230 SYNOP obs.
Upper-Air DA: None – Blending mode. Run: 66h/4 times a day
SURFEX model for surface and soil processesHARMONIE (2.5 km) - Orography
Avg. windspeed Dec. 2015 – scat/scores
ECOCLIMAP-I/II for Iceland
New PGD: Corine and AUI maps used
●
Three databases joined into new
ECOCLIMAP-II for Iceland
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Corine 2006/2012
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AUI Soil map used for non-veg.
areas
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Finally all vegitation over-written
with the best veg. map from AUI.
●
AUI → Agricultural Uni. of IcelandECOCLIMAP-II Iceland – Land cover database upgrade
Comparison old -> new
Soildepth Veg. Fr. LAINew vs old PGD verifcations for July 2012 T2m MSLP F10m RH2m
Cooperation with DMI started 2015
New EcoClimap-II binary maps complete – June 2016
●
Greenland ice sheet extent reduced in
new ECOCLIMAP-II (glacier cover type
turned into rocks)
●
Data from Greenland Mapping Project
(GIMP*) used
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Many improvements over Iceland
●
Went operational in IGA autumn 2016
(*) https://bpcrc.osu.edu/gdg/data/gimpdemCurrent HARMONIE-AROME domains
IGB
harmonie
IGAHarmonie: Rain and snow
Siglufjörður 27-28. Aug 2015 – Extreme precip.
HARMONIE: 48h Accumulated precipitation
Siglufjörður acc. precip. compared to observed
Precip verifcations: +6-30 & +30-54 h. (acc. 24h)
ICRA-2016: Iceland reanalysis Iceland reanalysis (ICRA-2016) project done in 2015-16. HARMONIE-AROME (cy38h1.2) at 2.5km resolution over the smaller previous domain. The new physiography used. The whole ERA-Interim period covered (1979-2017) and still being updated. Model in forecast mode and run 4xday with surface DA and selected 6-12h forecast felds make the main reanalysis dataset. IMO article: http://www.vedur.is/media/vedurstofan-utgafa-2017/VI_2017_005_rs.pdf Average annual precipitation Average snow on ground on May 1 (1981-2010) (1981-2010)
Storm February 21 2018
Harmonie 2.5 km orography
Harmonie 750 m orography
Harmonie 750 m wind forecast
Harmonie 2.5 km vs. 750 m
Snowdrift index valid at 14Z Feb. 3 2018
Vegagerðin observed snowdrift in the N and NV
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