presented at: european geoscience general assembly vienna, austria - april, 2011 authors:
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Coupled NMM-CALMET Meteorology Development for the CALPUFF Air
Dispersion Modelling in Complex Terrain and Shoreline Settings
Presented at:
European Geoscience General AssemblyVienna, Austria - April, 2011
Authors:
Zivorad Radonjic,* Dr. Douglas B. Chambers, Bosko Telenta and Dr. Zavisa Janjic
* Contact: Zivorad Radonjic, zradonjic@senes.ca
Overview• Introduction• Study Background• Approach To Simulations• Approach To Validation• Comparison of WRF-NMM Model Versions 3.1.1
and 3.2.1
• Effects of Horizontal Resolutions• Validation with Local Observations• One Year vs. Five Year Meteorological Datasets• Conclusions
Introduction
A study was undertaken to prepare and validate high-resolution three-dimensional meteorology suitable for use as input into the CALPUFF/CALMET air dispersion
model system in complex terrain with a shoreline.
The main goal was to demonstrate the good performance of CALMET in a setting that involves both complex terrain and a shoreline (land-water interface). Improvements in
CALMET performance possible using fine resolution meso-scale model inputs were also demonstrated.
Study Background
• Meteorology required for CALPUFF modelling of industrial site in complex terrain with shoreline– A challenging meteorological
environment• Site-specific meteorology
required for both long- and short-range modelling
• No local observational data available for time period in question
Approach To Simulations
• Weather Research and Forecasting - Nonhydrostatic Mesoscale Model (WRF-NMM) used as meso-scale model
• WRF-NMM modelled on 6 km and 2 km horizontal resolution
• WRF-NMM used to initialize CALMET modelled on 2 km and 250 m horizontal resolution
• 2009 meteorology modelled
Example Large Domain (6 km x 6 km resolution) for WRF-NMM Model
Example Small Domain (2 km x 2 km resolution) for WRF-NMM – CALMET Model
Approach To Validation
• Simulations validated by:– Comparison of two versions
of WRF-NMM– Comparison between models
run of different horizontal resolutions
– Comparison of simulations with observational data
• Wind Rose Comparisons• Descriptive Statistics
• All validations at 10 agl
Select Meteorological Stations Used for Model Validation
Comparison of WRF-NMM Model Versions
• WRF-NMM Versions 3.1.1 and 3.2.1 compared– Versions yielded similar results– Good predictions of wind direction– Wind speeds over-predicted due to averaging / surface– Roughness over water causes higher wind speed predictions
Wind Rose Comparison for Large WRF-NMM Domain (6 km resolution) - Charlo Airport
Wind Direction Frequency (%) Average Wind Speed (m/s)
48121620242832
N NNENE
ENE
E
ESE
SESSESSSW
SW
WSW
W
WNW
NWNNW
09-NMM-6km-V3.1.1
2009
09-NMM-6km-V3.2.1
Wind Rose - Charlo Airport 2009Wind Direction Frequency (%) (wind from)
2468
N NNENE
ENE
E
ESE
SESSESSSW
SW
WSW
W
WNW
NWNNW
09-NMM-6km-V3.1.1
2009
09-NMM-6km-V3.2.1
Average Wind Speed (m/s)
Note: Percentage of Calms: 2.22 %
48121620242832
N NNENE
ENE
E
ESE
SESSESSSW
SW
WSW
W
WNW
NWNNW
09-NMM-6km-V3.1.1
2009
09-NMM-6km-V3.2.1
Wind Rose - Charlo Airport 2009Wind Direction Frequency (%) (wind from)
2468
N NNENE
ENE
E
ESE
SESSESSSW
SW
WSW
W
WNW
NWNNW
09-NMM-6km-V3.1.1
2009
09-NMM-6km-V3.2.1
Average Wind Speed (m/s)
Note: Percentage of Calms: 2.22 %
Effects of Horizontal Resolutions - 1
• Both WRF-NMM simulations over-predict wind speed due to averaging / under-prediction of surface roughness over water / land interface
– Improved accuracy with finer (2 km) resolution
• WRF-NMM – CALMET simulation provides better prediction of wind speed due to better representation of surface characteristics and vertical resolution
• No significant improvement in agreement with wind direction between the three models.
Wind Rose Comparison for Gaspe Airport
Wind Direction Frequency (%) Average Wind Speed (m/s)
4812162024
N NNENE
ENE
E
ESE
SESSESSSW
SW
WSW
W
WNW
NWNNW
NMM-2.0km
2009
2009-NMM-6.0km
CALMET-2.0km
Wind Rose - Gaspe Airport 2009Wind Direction Frequency (%) (wind from)
246
8N
NNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNW
09-NMM-2.0km
2009
09-NMM-6.0km
CALMET-2.0km
Average Wind Speed (m/s)
Note: Percentage of Calms: 15.58 %
4812162024
N NNENE
ENE
E
ESE
SESSESSSW
SW
WSW
W
WNW
NWNNW
NMM-2.0km
2009
2009-NMM-6.0km
CALMET-2.0km
Wind Rose - Gaspe Airport 2009Wind Direction Frequency (%) (wind from)
2468
NNNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNW
09-NMM-2.0km
2009
09-NMM-6.0km
CALMET-2.0km
Average Wind Speed (m/s)
Note: Percentage of Calms: 15.58 %
Effects of Horizontal Resolutions - 2
• Wind speed predictions improve with finer resolution (250 m) WRF-NMM- CALMET model– Slight under-prediction versus over-prediction for other models
• No significant change in agreement with wind direction between the four models.
Wind Rose Comparison for Bathurst Airport
Wind Direction Frequency (%) Average Wind Speed (m/s)
Effects of Horizontal Resolutions - 3
• Descriptive statistics used to evaluate simulation results
Wind Speed Summary Statistics – Bathurst Station
MODEL – Horizontal ResolutionMODEL – Horizontal Resolution BiasBias MAEMAE RMSERMSEWRF-NMM - 6 kmWRF-NMM - 6 km 0.92 1.73 2.19WRF-NMM - 2 kmWRF-NMM - 2 km 0.82 1.72 2.19WRF-NMM/CALMET - 2 kmWRF-NMM/CALMET - 2 km -0.13 1.34 1.73WRF-NMM/CALMET - 250 mWRF-NMM/CALMET - 250 m -0.09 1.31 1.65
5.0
5.0
Pre
dic
tio
ns
(m
/s)
Observation (m/s)
PerfectAgreement
Factor of Two
WRF-NMM-6 km
WRF-NMM-2 km
CALMET-250 m
10.0
10.0
15.0
15.0
Q-Q Plot of Observed vs. Modelled Wind Speed – Bathurst Station
Effects of Horizontal Resolutions - 4
• Finer resolution improves:– BIAS (average of all the differences between forecast and observation)– Mean Average Error (the average magnitude of errors between forecast and
observation)– Root Mean Square Error (measures the average magnitude of the error in a set of
forecasts, with increase weighting on larger errors)
• Descriptive statistics consistent with wind rose data– Over-prediction of wind speeds at larger horizontal resolutions– Good agreement of wind speeds at smaller horizontal resolutions– More accurate predictions with higher horizontal resolutions– WRF-NMM/CALMET on 250 m resolution most accurate simulation
Validation with Local Observations - 1
• WRF-NMM/CALMET on 250 m horizontal resolution run for 2009 meteorology• Observations from local (2.5 km away) meteorological station available for
1999 to 2003• Good agreement noted between 2009 generated meteorology and
observational data
X - Site
X – Nearby Site
Validation with Local Observations - 2
Wind Direction Frequency (%) Average Wind Speed (m/s)
51015202530
NNNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNWSite-2009 -CALMET
Nearby-Site9903
Observation
Wind Direction Frequency (%)
5
10N
NNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNW
Site-2009 -CALMET
Nearby-Site9903
Observation
Average Wind Speed (km/h)
WIND ROSE Site Wind Roses - 2009 vs. Nearby Site 1999-2003
51015202530
NNNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNWSite-2009 -CALMET
Nearby-Site9903
Observation
Wind Direction Frequency (%)
5
10N
NNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNW
Site-2009 -CALMET
Nearby-Site9903
Observation
Average Wind Speed (km/h)
WIND ROSE Site Wind Roses - 2009 vs. Nearby Site 1999-2003
CALMET Derived Site Wind Rose 2009 vs. Nearby Site 1999-2003 Observations
One Year vs. Five Year Meteorological Datasets
• WRF-NMM/CALMET on 250 m horizontal resolution run for 2009 meteorology compared to 2004 to 2008 meteorology
• Differences between simulated meteorology for a 5-year period and a 1-year period are inconsequential
CALMET Derived Site Wind Rose 2009 vs. Nearby Site 1999-2003 Observations
Wind Direction Frequency (%) Average Wind Speed (m/s)
51015202530
NNNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNW
Site-2009 -CALMET
CALMET(2004-2008)
Wind Direction Frequency (%)
5
10N
NNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNW
Site-2009 -CALMET
CALMET(2004-2008)
Average Wind Speed (km/h)
WIND ROSE Site Wind Roses - CALMET (2009) vs. CALMET (2004-2008)
51015202530
NNNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNW
Site-2009 -CALMET
CALMET(2004-2008)
Wind Direction Frequency (%)
5
10N
NNE
NE
ENE
E
ESE
SE
SSES
SSW
SW
WSW
W
WNW
NW
NNW
Site-2009 -CALMET
CALMET(2004-2008)
Average Wind Speed (km/h)
WIND ROSE Site Wind Roses - CALMET (2009) vs. CALMET (2004-2008)
For well simulated meteorological data sets a single year of the derived three-dimensional meteorology can, for most purposes, be considered to provide a reasonable description of on-site observations.
Conclusions
1. Improvements in wind speeds predictions are achieved with use of finer resolution meso-scale meteorological modelling in shoreline complex terrain situations
2. Wind direction is not sensitive to effects of finer resolution modelling in these situations
3. Coupled WRF-NMM/CALMET system provides a sound alternate to costly and time consuming on-site data collection
4. One year of simulated meteorology corresponds closely to longer periods of record and can used satisfactorily in environmental assessments / air dispersion modelling if generated meteorology sufficiently represents on-site observations.
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