ukmetmodeller
New member
I've just been looking at the WRF-python code for calculating cloud cover. The python script uses the DCLOUDFRAC2 from wrf_cloud_fracf.f90 which all makes sense. I understand all elements of the process but I believe that the low / mid / high grouping is wrong when using pressure.
low_thresh = 97000
mid_thresh = 80000
high_thresh = 45000
I believe the requirements should be:
Low: full_p(k) <= low_thresh & > mid_thresh
Mid: full_p(k) <= mid_thresh & > high_thres
High: full_p(k) <= high_thresh
See below table for pressure levels at a single location (i,j)
This would put level k=8 into the low group (82997.47 Pa is greater than 80000 Pa and less than 97000).
However, DCLOUDFRAC2 puts it into the mid group based on the following fortan code:
kchi = -1
kcmi = -1
kclo = -1
DO k = 1,nz
IF (vert(i,j,k) .GT. low_thresh) kclo=k
IF (vert(i,j,k) .GT. mid_thresh) kcmi=k
IF (vert(i,j,k) .GT. high_thresh) kchi=k
END DO
Here kclo=-1, kcmi=8, kchi=14
Then base on the loop below pressure level k=8 (82997.47 Pa) is greater than or equal to kcmi and less than kchi so fits into the mid cloud group.
DO k = 1,nz
IF (k .GE. kclo .AND. k .LT. kcmi) THEN
lowc(i,j) = MAX(rh(i,j,k), lowc(i,j))
ELSE IF (k .GE. kcmi .AND. k .LT. kchi) THEN ! mid cloud
midc(i,j) = MAX(rh(i,j,k), midc(i,j))
ELSE if (k .GE. kchi) THEN ! high cloud
highc(i,j) = MAX(rh(i,j,k), highc(i,j))
END IF
END DO
This doesn't match the criteria of Mid: full_p(k) <= mid_thresh & > high_thres (mid <= 80000 and > 45000)
Does anyone know if this is a mistake or intentional?
low_thresh = 97000
mid_thresh = 80000
high_thresh = 45000
I believe the requirements should be:
Low: full_p(k) <= low_thresh & > mid_thresh
Mid: full_p(k) <= mid_thresh & > high_thres
High: full_p(k) <= high_thresh
See below table for pressure levels at a single location (i,j)
| k | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 |
| full_p | 96580.59 | 96057.03 | 95317.11 | 94014.46 | 92151.03 | 89689.49 | 86636.23 | 82997.47 | 78777.13 | 73980.17 | 68599.44 | 62624.09 | 56031.54 | 48747.43 | 40990.8 | 33650.34 | 27540.33 | 22820.15 | 18995.81 | 15398.71 | 11799.98 |
| <= low_thresh & >mid_thresh | 9.17E-01 | 0.951522 | 1 | 1 | 1 | 1 | 1.00E+00 | 7.47E-01 | |||||||||||||
| <= mid_thresh & >high_thresh | 0.172427 | 0 | 0 | 0 | 0 | 0 | |||||||||||||||
| <= high_thresh | 0.145057 | 0 | 0 | 0 | 0 | 0 | 0 |
This would put level k=8 into the low group (82997.47 Pa is greater than 80000 Pa and less than 97000).
However, DCLOUDFRAC2 puts it into the mid group based on the following fortan code:
kchi = -1
kcmi = -1
kclo = -1
DO k = 1,nz
IF (vert(i,j,k) .GT. low_thresh) kclo=k
IF (vert(i,j,k) .GT. mid_thresh) kcmi=k
IF (vert(i,j,k) .GT. high_thresh) kchi=k
END DO
Here kclo=-1, kcmi=8, kchi=14
Then base on the loop below pressure level k=8 (82997.47 Pa) is greater than or equal to kcmi and less than kchi so fits into the mid cloud group.
DO k = 1,nz
IF (k .GE. kclo .AND. k .LT. kcmi) THEN
lowc(i,j) = MAX(rh(i,j,k), lowc(i,j))
ELSE IF (k .GE. kcmi .AND. k .LT. kchi) THEN ! mid cloud
midc(i,j) = MAX(rh(i,j,k), midc(i,j))
ELSE if (k .GE. kchi) THEN ! high cloud
highc(i,j) = MAX(rh(i,j,k), highc(i,j))
END IF
END DO
This doesn't match the criteria of Mid: full_p(k) <= mid_thresh & > high_thres (mid <= 80000 and > 45000)
Does anyone know if this is a mistake or intentional?