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<p>Hello everyone,</p>
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<p>We are using WRF in an idealised set-up, with fixed SST and doubly periodic boundary conditions (Radiative-Convective Equilibrium).</p>
<p><span>I am running with dmpar configuration only (MPI calls active but no OMP), on 240 CPUs, for a 202*202*69 domain.</span><br>
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<p>In one of our experiment, we need to be able to keep the mean profiles of temperature and water vapour mixing ratio fixed, so we have decided to add a module for this type of nudging into WRF. This module is called directly by solve_em.F at the very beginning
of the solver. Unfortunately, the results exhibit a very strange behaviour of the variables, which seems to be due to parallelisation at first sight.</p>
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1) How to get the water vapour mixing ratio inside the WRF code? Am I right to use
<span>moist(ims,kms,jms,P_QV)</span> when calling the new subroutine that implements our profile nudging, in solve_em.F?<br>
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2) If I understand properly, the subroutine should use the "p" indices, as it is already parallelised and as in my case, the tile indices and the p indices are the same (we do not use smpar). Is it right to compute the average temperature and water vapour mixing
ratio over the whole domain via the following way? <br>
<br>
<div> DO k = kps , kpe<br>
sum_var_hor = 0.<br>
count_hor = 0.<br>
DO j = jps, min(jpe,jde-1) <br>
DO i = ips, min(ipe,ide-1) <br>
sum_var_hor = sum_var_hor + QV_CURR(i,k,j)<br>
count_hor = count_hor + 1.<br>
END DO<br>
END DO<br>
sum_var_hor = wrf_dm_sum_real ( sum_var_hor )<br>
count_hor = wrf_dm_sum_real ( count_hor )<br>
var_hor_average(k) = sum_var_hor / count_hor<br>
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3) Carrying on from the computation of the global average, I am trying to push the values at each level in one direction so that the mean value at that level relaxes towards a target profile. This is what I have called profile nudging. Is the following code
doing the expected job in relaxing ALL points by a value that only depends on the vertical axis?<br>
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<div> dQV_CURR_strong_nudging(k) = - ( var_hor_average(k) - QVAPOR_target_prof(k) ) * nudging_coefficient_var<br>
DO j = jps, min(jpe,jde-1) !jps , jpe<br>
DO i = ips, min(ipe,ide-1) !ips , ipe<br>
write(6,*) 'i and j are ', i, j<br>
QV_CURR(i,k,j) = QV_CURR(i,k,j) + dQV_CURR_strong_nudging(k)<br>
END DO<br>
END DO<br>
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To give everybody an idea of what the problem looks like, I attach an (x,y) view of potential temperature and water vapour mixing ratio which show the weirdest behaviour ever.<br>
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I have been working on this for ages, and can't find where my code is wrong, and why it gives this weird division into 16 bands on the y axis only, as my code is very symmetric on x and y.<br>
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I could also point out that this weird behaviour seems to vanish when I only implement the profile nudging on potential temperature only (not relaxing water vapour at all).<br>
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Thank you very much for your help,<br>
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Kind regards,<br>
<br>
Maxime.<br>
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