Temporal changing surface fields: tidal wetlands

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maresbarekzai
Posts: 2
Joined: Thu Jul 29, 2021 8:37 pm

Temporal changing surface fields: tidal wetlands

Post by maresbarekzai » Fri Jul 30, 2021 11:25 am

Dear WRF Community,

I am analyzing the impact of tidal wetlands on WRF Simulations.
The Tidal wetlands alternate between wet and dry every 6 hours in an approximately sinusoidal fashion.
For that I need to feed the model changing Landmask, SST and LandUse (maybe others?) fields at some temporal interval.
Is there a way to do this? Maybe an existing nudging approach?

Thanks in Advance, Mares

kwerner
Posts: 2440
Joined: Wed Feb 14, 2018 9:21 pm

Re: Temporal changing surface fields: tidal wetlands

Post by kwerner » Tue Aug 03, 2021 7:04 pm

Hi,
I discussed your issue with our physics expert. They said they wouldn't change the landmask, but maybe modify some key properties and use SST for the water periods. The soil temperature would also need to respond to SST. Is this a long simulation that needs to update SST (typically more than about a week)?
NCAR/MMM

maresbarekzai
Posts: 2
Joined: Thu Jul 29, 2021 8:37 pm

Re: Temporal changing surface fields: tidal wetlands

Post by maresbarekzai » Mon Aug 23, 2021 12:33 pm

Hi kwerner,
thanks for your reply. It took me a while, but this is how I approached the problem. Please tell me if I am doing something terribly wrong here.

First, I wrote a python script that generates me a tidal_mask field that is equal to one at the tidal wetlands and zero else.
Furthermore, this file contains the ssh (sea surface height) every 15 minutes downloaded from copernicus data hub.
Finally, the SST is also read in from ERA5 and modified to fit the tidal phase.

These fields are then added to wrflowinput_<domain> and read in with a auxinput4_interval of 15 minutes.

To control the program flow, I added the namelist option tidal_update.

The main changes happen in the module_surface_driver.F
Here, I added a block that changes the pixel from ocean to land and vice versa.
Right before the sst_update block.

Code: Select all

  IF (tidal_update .eq. 1) THEN
    CALL wrf_debug( 100, 'TIDAL_UPDATE is on' )
    DO ij = 1 , num_tiles
      DO j=j_start(ij),j_end(ij)
      DO i=i_start(ij),i_end(ij)
        if(tidal_mask(i,j) .eq. 1) then
          if(ssh(i,j) .gt. 0) then
            ! turn into ocean pixel
            LANDMASK(i,j) = 0
            XLAND(i,j) = 2
            LU_INDEX(i,j) = iswater
            IVGTYP(i,j) = iswater
            VEGFRA(i,j) = 0
            ISLTYP(i,j) = 14
            ALBEDO(i,j) = 0.08
            ALBBCK(i,j) = 0.08
            EMISS(i,j) = 0.98
            EMBCK(i,j) = 0.98
            Z0(i,j) = 1.e-4
            MAVAIL(i,j) = 1
            DO nk = 1, num_soil_layers
              TSLB(i,nk,j) = SST(i,j)
              SMOIS(i,nk,j) = 1
              SH2O(i,nk,j) = 1
            ENDDO
            TMN(i,j) = SST(i,j)
            TSK(i,j) = SST(i,j)
          else if(ssh(i,j) .lt. 0) then
            ! turn into land pixel
            LANDMASK(i,j) = 1
            XLAND(i,j) = 1
            LU_INDEX(i,j) = iswetland
            IVGTYP(i,j) = iswetland
            VEGFRA(i,j) = 81.58
            ISLTYP(i,j) = 9
            ALBEDO(i,j) = 0.14
            ALBBCK(i,j) = 0.17
            EMISS(i,j) = 0.95
            EMBCK(i,j) = 0.95
            Z0(i,j) = 0.2
            MAVAIL(i,j) = 0.6
            DO nk = 1, num_soil_layers
              !TSLB(i,nk,j) = SST(i,j)
              SMOIS(i,nk,j) = 0.14
              SH2O(i,nk,j) = 0.14
            ENDDO
            !TMN(i,j) = SST(i,j)
            !TSK(i,j) = SST(i,j)
          endif
        endif
      ENDDO ! i
      ENDDO ! j
    ENDDO ! ij
  ENDIF ! tidal_update
If you have concernes or tipps I would be very happy to hear them.

All the best,
Mares

kwerner
Posts: 2440
Joined: Wed Feb 14, 2018 9:21 pm

Re: Temporal changing surface fields: tidal wetlands

Post by kwerner » Tue Aug 24, 2021 10:35 pm

Hi Mares,
From what you describe, it sounds like you're on the right path. I would suggest running a short/simple simulation and take a look at the output to see if it's what you expect.
NCAR/MMM

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