WRF atmosphere energy budget

Lixiang

New member
Hi All,

I am using WRF (WRFV4.4.1) to test the RCE case. The testcase "em_convrad" is used and no changes are made. After about 700 hrs of integration, I find that I can not close the energy budget of the atmosphere.

1. The way I calculated the energy budget is:
Net energy at the bottom = -swdnb + swupb - lwdnb + lwupb + sh+lh;
Net energy at the top = swdnt - swupt + lwdnt - lwupt;
Net atmosphere energy = Net energy at the bottom + Net energy at the top;
I averaged the net atmosphere energy over the last ~96 hours and result is about +10 W/m2 (using 48 or 72 hours gives similar results). I have also attached a figure ('testcase_energy.png') below. I thought it would be around 0, representing the balanced state. Am I doing anything wrong or am I missing some terms of the atmosphere energy?

2. I have also tried to calculate the energy budget suggested by kwerner in this thread "WRF energy and moisture budget?", which is:
surface energy = RNET+GRDFLX-HFX-LH
I compared this surface energy with the Net energy at the bottom in 1 and the figure is attached ('testcase_bottom_calculation_method_comparison.png'). The sign of "Net energy at the bottom" is reversed for a clearer comparison. This two seem to give the same result, which means the method in 2 does not affect the atmosphere energy budget as I understand.
I have also checked the variable NOAHRES, which is a constant 0 in my output. The GRDFLX is also a constant 0.

Any hints about the atmosphere energy budget calculation would be very much appreciated!! Thanks!
 

Attachments

  • testcase_energy.png
    testcase_energy.png
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  • testcase_bottom_calculation_method_comparison.png
    testcase_bottom_calculation_method_comparison.png
    127.3 KB · Views: 0

Ming Chen

Moderator
Staff member
Net energy at the bottom = swdnb - swupb + lwdnb - lwupb - sh-lh
Net energy at the top = swdnt - swupt + lwdnt - lwupt
 

Lixiang

New member
Net energy at the bottom = swdnb - swupb + lwdnb - lwupb - sh-lh
Net energy at the top = swdnt - swupt + lwdnt - lwupt
Thank you for the reply!

But I reversed the sign of 'Net energy at the bottom' merely to make the atmosphere gain energy when it is positive, so I guess it will not affect the Net atmosphere energy calculation.

Please let me know if you have any advice. Thanks a lot!
 
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