Opened 3 years ago

Last modified 14 months ago

#467 assigned defect

Understand the abrupt changes of vbeta

Reported by: fcheruy Owned by: somebody
Priority: major Milestone: Not scheduled yet
Component: Physical processes Version: trunc
Keywords: Cc:

Description (last modified by jgipsl)

Exploring the reasons why t2m_max and q2m (interpolated between the surface and the first atmospheric level owing to MO laws) it appeared that the problem occured for near saturation values of qsurf. For the cases investigated, the problem shows up only for one time-step (during the night, without rain, over semi-arid areas).
It is related to abrupt change in vbeta1 and vbeta3.
The problem exists even when ORCHIDEE is forced with tair and qair from LMDZ so it is not a consequence of the irrealistic values of t2m.

Abrupt change in vbeta1 and vbeta3 can occur when there is no turbulence and no wind and when the soil moisture is far from the wilting point. This can give unrealistc values of qsurf when the atmosphere is dry.
It has been limited by avoiding too low values for qc ( qc=speed*drag ) in enerbil, see [6018], [6019].

It would be safe to understand if the abrupt changes of vbeta in ORCHIDEE are realistic.

Attachments (1)

q2maveclmohumide.png (108.4 KB) - added by fcheruy 3 years ago.

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Change History (6)

Changed 3 years ago by fcheruy

comment:1 Changed 2 years ago by aducharne

  • Milestone set to ORCHIDEE 3.0
  • Owner changed from somebody to fcheruy
  • Status changed from new to assigned

Linked to tickets #468 et #480

comment:2 Changed 2 years ago by jgipsl

  • Component changed from Anthropogenic processes to Physical processes
  • Description modified (diff)
  • Milestone changed from ORCHIDEE 3.0 to ORCHIDEE 4.0
  • Owner changed from fcheruy to somebody
  • Summary changed from t2m_max (at the time step) to Understand the abrupt changes of vbeta

comment:3 Changed 2 years ago by jgipsl

At the same time, the calculation of the diagnostics for the 2-meter values in LMDZ have been revised and will be commited in the near future version of LMDZ.
/F. Cheruy

comment:4 Changed 14 months ago by luyssaert

  • Milestone changed from ORCHIDEE 4.0 to Not scheduled yet
  • Version set to trunc

comment:5 Changed 14 months ago by aducharne

Might be worth to process with ticket #350

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