[ncl-talk] averaging of height levels
Dennis Shea
shea at ucar.edu
Tue Oct 20 20:05:48 MDT 2020
The following is what I would do.
=====
The 'zfull' has lat and lon coordinate variables.
'zfull' does not have any vertical coordinate variable.
"nVertLevelsP" is the name of the interface level dimension
However, it no values are associated with it.
Further, based upon the 'zfulls long name ... the variable contains
*INTERFACE* values.
There is one more interface level than "mid levels".
===============================================
; zfull(latitude,longitude,nVertLevelsP) ; (98,108,54)
; Coordinates:
; latitude: [31.6178..42.50189]
; longitude: [-129.0292..-113.0208]
; long_name: Geometric height of layer INTERFACES
; units : m MSL
dims_zfull = dimsizes(zfull)
nlat = dims_zfull(0)
mlon = dims_zfull(1)
klevi = dims_zfull(2) ; number of *INTERFACE* levels
; Compute heights at mid-levels using interface values
zmid = 0.5*( zfull(:,:,0:klevi-2)+zfull(:,:,1:klevi-1) )
zmid at long_name = "Geometric height of mid-levels"
zmid at units = zfull at units
copy_VarCoords(zfull(:,:,0), zmid(:,:,0))
zmid!2 = "levz_mid" ; name vertical coordinate variable
printVarSummary(zmid) ; zmid(latitude,longitude,levz_mid) ;
(98,108,53)
printMinMax(zmid,1)
print("==========")
; Create nominal mid-level surfaces.
;;levz_mid = (/.../) ; klev = klevi-1 (one less than the number
of interface levels
;;levz_mid!0 = "levz_mid"
;;levz_mid at long_name = "nominal height for mid-level surfaces"
;;levz_mid at units = zmid at units
;;;zmid&levz_mid = levz_mid ; assign values to vertical coord
variable
;;printVarSummary(zmid)
;;printMinMax(zmid,1)
;;print("==========")
On Tue, Oct 20, 2020 at 5:15 PM Gurer, Kemal at ARB <kemal.gurer at arb.ca.gov>
wrote:
> Hello again,
>
>
>
> I forgot to include the mid-level information about the zhalf1, zhalf2:
>
>
>
> Variable: zz1
>
> Type: float
>
> Total Size: 2286144 bytes
>
> 571536 values
>
> Number of Dimensions: 3
>
> Dimensions and sizes: [latitude | 98] x [longitude | 108] x [levs | 54]
>
> Coordinates:
>
> latitude: [31.6178..42.50189]
>
> longitude: [-129.0292..-113.0208]
>
> levs: [9.96921e+36..9.96921e+36]
>
> Number Of Attributes: 1
>
> _FillValue : 9.96921e+36
>
> (0) min=-64.3161 max=28858.8
>
>
>
> Variable: zhalf1
>
> Type: float
>
> Total Size: 2286144 bytes
>
> 571536 values
>
> Number of Dimensions: 3
>
> Dimensions and sizes: [levs | 54] x [latitude | 98] x [longitude | 108]
>
> Coordinates:
>
> levs: [9.96921e+36..9.96921e+36]
>
> latitude: [31.6178..42.50189]
>
> longitude: [-129.0292..-113.0208]
>
> Number Of Attributes: 1
>
> _FillValue : 9.96921e+36
>
>
>
> Variable: zz2
>
> Type: float
>
> Total Size: 2286144 bytes
>
> 571536 values
>
> Number of Dimensions: 3
>
> Dimensions and sizes: [latitude | 98] x [longitude | 108] x [levs | 54]
>
> Coordinates:
>
> latitude: [31.6178..42.50189]
>
> longitude: [-129.0292..-113.0208]
>
> levs: [9.96921e+36..9.96921e+36]
>
> Number Of Attributes: 1
>
> _FillValue : 9.96921e+36
>
> (0) min=-64.3161 max=28858.8
>
>
>
> Variable: zhalf2
>
> Type: float
>
> Total Size: 2286144 bytes
>
> 571536 values
>
> Number of Dimensions: 3
>
> Dimensions and sizes: [levs | 54] x [latitude | 98] x [longitude | 108]
>
> Coordinates:
>
> levs: [9.96921e+36..9.96921e+36]
>
> latitude: [31.6178..42.50189]
>
> longitude: [-129.0292..-113.0208]
>
> Number Of Attributes: 1
>
> _FillValue : 9.96921e+36
>
>
>
> ---------------------------------------------------------
>
> Also, the additional information about zfull variable:
>
>
>
> Variable: zfull
>
> Type: float
>
> Total Size: 2370816 bytes
>
> 592704 values
>
> Number of Dimensions: 3
>
> Dimensions and sizes: [latitude | 98] x [longitude | 108] x
> [nVertLevelsP1 | 56]
>
> Coordinates:
>
> latitude: [31.6178..42.50189]
>
> longitude: [-129.0292..-113.0208]
>
> Number Of Attributes: 2
>
> long_name : Geometric height of layer interfaces
>
> units : m MSL
>
> (0) Geometric height of layer interfaces (m MSL) : min=-74.3167
> max=29983.8
>
>
>
> Thanks again for your help.
>
>
>
> Kemal.
>
>
>
> *From:* Gurer, Kemal at ARB
> *Sent:* Tuesday, October 20, 2020 4:10 PM
> *To:* Dennis Shea <shea at ucar.edu>; ncl-talk at ucar.edu
> *Subject:* RE: [ncl-talk] averaging of height levels
>
>
>
> Hello Dennis,
>
>
>
> I agree with you. I always included the outcome of my code in the past,
> but this time knowing almost for sure that I am making an obvious error
> somewhere that I cannot see, I assumed someone who is more experienced than
> me would catch it right away. I am sorry for not sending a complete
> question.
>
>
>
> Here is my code in attempting to calculate the mid-level heights from full
> level heights via two method:
>
>
>
> ; ------- 1st variable and method
> ------------------------------------------------------
>
>
>
> zz1 = new((/nlats, nlons, nlevs-1/),"float")
>
>
>
> zz1!0 = "latitude"
>
> zz1!1 = "longitude"
>
> zz1!2 = "levs"
>
> zz1&latitude = latitude
>
> zz1&longitude = longitude
>
> zz1&levs = levs
>
>
>
> do i=0,nlevs-2
>
> zz1(:,:,i) = 0.5 * (zfull(:,:,i)+zfull(:,:,i+1))
>
> end do
>
>
>
> printVarSummary(zz1)
>
> printMinMax(zz1,0)
>
>
>
> zhalf1 = zz1(levs|:,latitude|:,longitude|:)
>
> printVarSummary(zhalf1)
>
>
>
> ; ------- 2nd variable and method
> ------------------------------------------------------
>
>
>
> zz2 = new((/nlats, nlons, nlevs-1/),"float")
>
>
>
> zz2!0 = "latitude"
>
> zz2!1 = "longitude"
>
> zz2!2 = "levs"
>
> zz2&latitude = latitude
>
> zz2&longitude = longitude
>
> zz2&levs = levs
>
>
>
> zz2 = 0.5*( zfull(:,:,0:nlevs-2) + zfull(:,:,1:nlevs-1) )
>
>
>
> printVarSummary(zz2)
>
> printMinMax(zz2,0)
>
>
>
> zhalf2 = zz2(levs|:,latitude|:,longitude|:)
>
> printVarSummary(zhalf2)
>
> ; -------------------------------------------------------------
>
>
>
> Here is the outcome of zfull values at zfull(0,0,:)
>
>
>
> zfull =
>
> 0, 20, 44, 72.8, 107.4, 148.8, 198.6, 258.3, 330, 416, 519.2, 643, 791.6,
>
> 969.9001, 1183.9, 1440.7, 1748.8, 2118.6, 2562.3, 3094.8, 3733.8,
> 4483.8,
>
> 5233.799, 5983.799, 6733.8, 7483.799, 8233.8, 8983.8, 9733.8, 10483.8,
>
> 11233.8, 11983.8, 12733.8, 13483.8, 14233.8, 14983.8, 15733.8, 16483.8,
>
> 17233.8, 17983.8, 18733.8, 19483.8, 20233.8, 20983.8, 21733.8, 22483.8,
>
> 23233.8, 23983.8, 24733.8, 25483.8, 26233.8, 26983.8, 27733.8, 28483.8,
>
> 29233.8, 29983.8, 0, 20, 44, 72.8, 107.4, 148.8, 198.6, 258.3, 330,
> 416,
>
> 519.2, 643, 791.6, 969.9, 1183.9, 1440.7, 1748.8, 2118.6, 2562.3,
> 3094.8,
>
> 3733.8, 4483.8, 5233.8, 5983.8, 6733.8, 7483.8, 8233.8, 8983.8, 9733.8,
>
> 10483.8, 11233.8, 11983.8, 12733.8, 13483.8, 14233.8, 14983.8, 15733.8,
>
> 16483.8, 17233.8, 17983.8, 18733.8, 19483.8, 20233.8, 20983.8, 21733.8,
>
> 22483.8, 23233.8, 23983.8, 24733.8, 25483.8, 26233.8, 26983.8,
>
> 27733.8, 28483.8, 29233.8, 29983.8
>
>
>
> Here is the outcome of both zhalf1 and zhalf2 at (0,0,:) point:
>
>
>
> zhalf1 and 2 =
>
> 9.999999, 10, 10, 10, 10, 10, 10, 10, 10, 10, 9.999999, 10, 10, 10, 10,
> 10,
>
> 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
>
> 10, 10, 10, 9.999999, 10, 10, 10, 9.999999, 10, 10, 10, 10, 10, 10, 10,
>
> 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
>
> 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10,
> 423.6477,
>
> 378.6578, 662.8945, 1097.154, 1152.52, 1072.004, 1299.672, 1005.835,
>
> 592.6567, 270.4732, 318.5765, 13.87211, 13.37675, 10, 10, 49.30841,
>
> 48.51982, 38.2547, 10.43509, 20.66064, 89.90919, 139.163, 114.4501,
>
> 201.582, 276.1719,
>
> 10, 10, 10, 10, 10, 10, 10,
>
>
>
> Thank you for your time and expertise. With regards,
>
>
>
> Kemal.
>
>
>
> *From:* Dennis Shea <shea at ucar.edu>
> *Sent:* Tuesday, October 20, 2020 3:40 PM
> *To:* Gurer, Kemal at ARB <kemal.gurer at arb.ca.gov>
> *Cc:* ncl-talk at ucar.edu
> *Subject:* Re: [ncl-talk] averaging of height levels
>
>
>
> *CAUTION: This email originated from outside of the organization. Do not
> click links or open attachments unless you recognize the sender and know
> the content is safe.*
>
> It is ALWAYS best to include the output from printVarSummary when
> submitting a question.
>
>
>
> printVarSummary(zfull)
>
> ===
>
> To me, what you have done is correct.
>
>
>
> A statement like: "since the half height levels are strange"
>
>
>
> does not tell people much. What is "strange" about the values?
>
>
>
>
>
>
>
> On Mon, Oct 19, 2020 at 4:15 PM Gurer, Kemal at ARB via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
> Hi ncl’ers,
>
>
>
> I have a 3d array for the full model height levels, say,
> zfull(nlat,nlon,nlevs). I want to calculate the midpoints of the height
> levels of the full model heights and put it into a new array, say
> zhalf(nlat,nlon,nlevs-1). The following code:
>
>
>
> do i=0,nlevs-2
>
> zhalf(:,:,i) = 0.5 * (zfull(:,:,i)+zfull(:,:,i+1))
>
> end do
>
>
>
> or, the following code:
>
>
>
> zhalf = 0.5*( zfull(:,:,0:nlevs-2) + zfull(:,:,1:nlevs-1) )
>
>
>
> generates some data, but I don’t know and think what I am doing is right
> since the half height levels are strange. How can I calculate the
> mid-points of height levels of a 3d array of height levels?
>
>
>
> Thank you for your help.
>
>
>
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