[Wrf-users] FW: Do these VAR results look normal? -background errorseem increasing.
Kemp, Eric M (IS)
ERIC.KEMP at ngc.com
Mon Apr 6 07:15:36 MDT 2009
Abdullah:
What you're seeing is normal. The Jb term is based on the squared difference between the analysis and the background (A-B)**2. So as the WRF-Var adjusts the analysis to more closely fit the observations, (A-B)**2 will increase, and so will Jb. How much weight is given to Jb depends on the background error covariance, along with the observation error covariance used with Jo.
Look at Chapter 9 of the WRF Technical Report for more info on the J equation:
http://www.mmm.ucar.edu/wrf/users/docs/arw_v3.pdf
-Eric
Eric M. Kemp
Meteorologist
Northrop Grumman Information Systems
Advisory Services Division (TASC)
4801 Stonecroft Boulevard
Chantilly, VA 20151
301-286-9768 (NASA Goddard Office)
703-633-8300 x7078 (Chantilly SLEET Lab)
703-633-8300 x8278 (Chantilly Office)
703-449-3400 (Chantilly Fax)
-----Original Message-----
From: wrf-users-bounces at ucar.edu on behalf of Abdullah Kahraman
Sent: Mon 4/6/2009 7:46 AM
To: wrfhelp; wrf-users at ucar.edu
Subject: [Wrf-users] Do these VAR results look normal? -background errorseem increasing.
Hello,
After running wrfvar, I have the following cost_fn and grad_fn values.
Background errors seem increasing, isn't this some unexpected thing for an
assimilation?
Regards,
Abdullah KAHRAMAN
Istanbul Technical University
Department of Meteorology
Outer EPS Inner J Jb Jo Jc
Je Jp
Iter Iter
1 0.100E-01 0 1330.654 0.000 1330.654 0.000
0.000 0.000
1 0.100E-01 1 1192.440 3.507 1188.932 0.000
0.000 0.000
1 0.100E-01 2 1135.046 10.494 1124.551 0.000
0.000 0.000
1 0.100E-01 3 1107.064 18.346 1088.717 0.000
0.000 0.000
1 0.100E-01 4 1097.412 22.466 1074.946 0.000
0.000 0.000
1 0.100E-01 5 1089.968 26.775 1063.193 0.000
0.000 0.000
1 0.100E-01 6 1086.380 29.538 1056.842 0.000
0.000 0.000
1 0.100E-01 7 1083.551 32.328 1051.223 0.000
0.000 0.000
1 0.100E-01 8 1081.911 34.356 1047.555 0.000
0.000 0.000
1 0.100E-01 9 1080.408 36.694 1043.714 0.000
0.000 0.000
1 0.100E-01 10 1079.996 37.447 1042.549 0.000
0.000 0.000
1 0.100E-01 11 1079.709 38.023 1041.686 0.000
0.000 0.000
1 0.100E-01 12 1079.522 38.441 1041.080 0.000
0.000 0.000
1 0.100E-01 13 1079.348 38.885 1040.462 0.000
0.000 0.000
1 0.100E-01 14 1079.274 39.096 1040.178 0.000
0.000 0.000
1 0.100E-01 15 1079.217 39.278 1039.939 0.000
0.000 0.000
Outer EPS Inner G Gb Go Ge
Gp
Iter Iter
1 0.100E-01 0 104.371 0.000 104.371 0.000 0.000
1 0.100E-01 1 43.578 2.649 43.658 0.000 0.000
1 0.100E-01 2 32.406 4.581 32.729 0.000 0.000
1 0.100E-01 3 26.256 6.057 26.946 0.000 0.000
1 0.100E-01 4 17.494 6.703 18.734 0.000 0.000
1 0.100E-01 5 11.674 7.318 13.778 0.000 0.000
1 0.100E-01 6 11.721 7.686 14.017 0.000 0.000
1 0.100E-01 7 7.221 8.041 10.808 0.000 0.000
1 0.100E-01 8 6.672 8.289 10.641 0.000 0.000
1 0.100E-01 9 4.975 8.567 9.907 0.000 0.000
1 0.100E-01 10 4.032 8.654 9.547 0.000 0.000
1 0.100E-01 11 2.293 8.720 9.017 0.000 0.000
1 0.100E-01 12 2.437 8.768 9.101 0.000 0.000
1 0.100E-01 13 1.535 8.819 8.951 0.000 0.000
1 0.100E-01 14 1.586 8.843 8.984 0.000 0.000
1 0.100E-01 15 1.002 8.863 8.920 0.000 0.000
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