extreme value of precipitation over tropic – in #8: General Questions

in #8: General Questions

<p> Important is to damp the gravity waves sufficiently. <br/> Hereto a test series should be considered with the alternative wave damping where w is damped only. </p> <p> Using the standard approach the coefficient nrdtau can be chosen smaller to make the damping stronger. <br/> In this case the damping zone can be made thinner. However, too strong damping reflects the waves within the damping layer. <br/> A typical optimisation problem. <br/> In any case, the damping should be rather too strong than too weak. <br/> Higher mountains need stronger damping because the vertical propagation speed is increasing with the slope of the mountains. </p> <p> I plan an article for the <span class="caps"> COSMO </span> newsletter on this topic and a revision of the namelist parameter description. </p> <p> Greetings, Andreas </p>

  @andreaswill in #701d377

<p> Important is to damp the gravity waves sufficiently. <br/> Hereto a test series should be considered with the alternative wave damping where w is damped only. </p> <p> Using the standard approach the coefficient nrdtau can be chosen smaller to make the damping stronger. <br/> In this case the damping zone can be made thinner. However, too strong damping reflects the waves within the damping layer. <br/> A typical optimisation problem. <br/> In any case, the damping should be rather too strong than too weak. <br/> Higher mountains need stronger damping because the vertical propagation speed is increasing with the slope of the mountains. </p> <p> I plan an article for the <span class="caps"> COSMO </span> newsletter on this topic and a revision of the namelist parameter description. </p> <p> Greetings, Andreas </p>
AW replied

Important is to damp the gravity waves sufficiently.
Hereto a test series should be considered with the alternative wave damping where w is damped only.

Using the standard approach the coefficient nrdtau can be chosen smaller to make the damping stronger.
In this case the damping zone can be made thinner. However, too strong damping reflects the waves within the damping layer.
A typical optimisation problem.
In any case, the damping should be rather too strong than too weak.
Higher mountains need stronger damping because the vertical propagation speed is increasing with the slope of the mountains.

I plan an article for the COSMO newsletter on this topic and a revision of the namelist parameter description.

Greetings, Andreas

View in channel