Embed Size (px)
DESCRIPTION
CARPE DIEM. 5th meeting. Dublin, December 2003. Bernat Codina, Miquel Picanyol Dept. of Astronomy and Meteorology University of Barcelona. WP 3: Data assimilation. Contribution to WP3 (Data Assimilation): Experiment comparison between the IAU and nudging methods. - PowerPoint PPT Presentation
Citation preview
1
CARPE DIEM
Bernat Codina, Miquel Picanyol
Dept. of Astronomy and Meteorology
University of Barcelona
5th meeting. Dublin, December 2003.
2
WP 3: Data assimilation
Contribution to WP3 (Data Assimilation):
•Experiment comparison between the IAU and nudging methods.
•Assess the impact on the precipitation field.
3
WP 3: Data assimilation
Description of the experiment:
•Corrections on the T,u,v,q and ps variables are introduced via IAU and nudging methods.
•Assimilation frequency: 6 and 3 hours.
•10 different cases.
4
WP 3: Data assimilation
Methodology:
First guess
First guess
First guess+
Observations
“Perfect OBS”
IAU/Nudging
Control
5
WP 3: Data assimilationSurface temperature
6
WP 3: Data assimilationU 850hPa
7
WP 3: Data assimilationSfc – 500hPa RH
8
WP 3: Data assimilation
ME = 4.1 RMSE = 14.1 ME = -0.7 RMSE = 12.6
ME = 4.2 RMSE = 17.7
ME = -0.8 RMSE = 14.9
ME = 1.2 RMSE = 17.9
Total precipitation
9
WP 3: Data assimilation
ME = -0.2 RMSE = 16.8 ME = 0.8 RMSE = 9.3
ME = -0.04 RMSE = 12.4 ME = 1.1 RMSE = 6.9 ME = 0.2 RMSE = 7.1
Total precipitation
10
WP 3: Data assimilation
ME = -0.2 RMSE = 23.8 ME = 6.0 RMSE = 23.4
ME = 0.2 RMSE = 22.9 ME = 6.6 RMSE = 19.4 ME = 0.5 RMSE = 19.0
Total precipitation
11
WP 3: Data assimilation
Case Control IAU 6 NUDG 6 IAU 3 NUDG 3
021209 -5.8 2.0 -3.4 3.5 -2.2
030105 1.2 4.2 -0.8 4.1 -0.7
030212 -0.16 0.8 -0.01 1.1 0.2
030219 3.0 2.5 -0.6 3.5 -0.5
030226 -0.81 5.4 1.2 6.7 1.3
030327 -2.1 5.7 -0.5 6.0 -0.1
030408 1.2 1.0 0.4 0.6 0.3
030505 -0.2 6.0 0.2 6.6 0.5
030816 3.5 1.2 0.8 2.0 -1.4
030830 2.0 2.0 0.8 1.0 0.5
Total precipitation mean error
12
WP 3: Data assimilation
Case Control IAU 6 NUDG 6 IAU 3 NUDG 3
021209 19.7 23.2 19.8 16.1 14.8
030105 17.9 17.7 14.9 14.1 12.6
030212 16.8 9.3 12.5 6.9 7.1
030219 30.8 24.7 26.5 20.8 21.7
030226 21.2 21.0 21.8 17.5 15.8
030327 22.0 18.9 17.5 18.6 13.2
030408 5.7 4.4 3.8 3.5 3.1
030505 23.8 23.4 22.9 19.4 19.0
030816 23.3 17.7 13.5 16.8 12.9
030830 7.5 4.7 3.5 3.7 2.6
Total precipitation RMSE
13
WP 3: Data assimilation
Conclusions:
•Best results in 3-hour frequency assimilation.
•IAU tends to overestimate precipitation.
•3-hour nudging assimilation minimizes the total precipitation RMSE.
•Verification of precipitation:
•RMSE severely penalizes mislocation errors.
•Other verification methods could be applied. [Ebert & McBride, 2000]
