[ncl-talk] ncep cfsr: hybrid a / hybrid a
Matt Masarik
mattmasarik at boisestate.edu
Mon Jun 4 16:55:59 MDT 2018
That's perfect. Thanks, Dennis.
cheers,
matt
On Mon, Jun 4, 2018 at 4:50 PM, Dennis Shea <shea at ucar.edu> wrote:
> Forgot:
>
>
> CFSR uses:
>
>
> Pk = Ak + Bk*Psfc
>
>
> NCL's pres_hybrid_ccm uses a slightly different formulation. It uses
>
> the formula *p = a(k)*p0 + b(k)*ps*.
>
> The CFSR uses, *ap(k) [=a(k)*p0]*, which has units of pressure.
>
> You must nake a(k) dimensionless prior to use.
>
>
> Good luck
>
> On Mon, Jun 4, 2018 at 4:44 PM, Dennis Shea <shea at ucar.edu> wrote:
>
>>
>>
>> You did not give any information on the source dataset you are using.
>> Hence, hard to answer.
>> Maybe the following will help:
>>
>> Source: https://rda.ucar.edu/datasets/ds093.1/docs/FAQs_hrly_timeser
>> ies.html
>>
>> The Climate Forecast System uses a hybrid vertical coordinate that is
>> defined by:
>> Pk = Ak + Bk*Psfc
>> where Pk is the pressure at level k, and Psfc is the surface
>> pressure
>> The values of Ak and Bk (units are Pa) are given in the following
>> table:
>> kAB
>> 0 0.0 1.0
>> 1 0.0 0.99467117 (This is Hybrid Level 1)
>> 2 0.57499999 0.99862660
>> 3 5.7410002 0.98174226
>> 4 21.516001 0.97386760
>> 5 55.712002 0.96482760
>> 6 116.89900 0.95443410
>> 7 214.01500 0.94249105
>> 8 356.22299 0.92879730
>> 9 552.71997 0.91315103
>> 10 812.48901 0.89535499
>> 11 1143.9880 0.87522358
>> 12 1554.7889 0.85259068
>> 13 2051.1499 0.82731885
>> 14 2637.5530 0.79930973
>> 15 3316.2170 0.76851469
>> 16 4086.6140 0.73494524
>> 17 4945.0288 0.69868290
>> 18 5884.2061 0.65988702
>> 19 6893.1172 0.61879963
>> 20 7956.9082 0.57574666
>> 21 9057.0508 0.53113484
>> 22 10171.712 0.48544332
>> 23 11276.348 0.43921080
>> 24 12344.490 0.39301825
>> 25 13348.671 0.34746850
>> 26 14261.435 0.30316412
>> 27 15056.342 0.26068544
>> 28 15708.893 0.22057019
>> 29 16197.315 0.18329623
>> 30 16503.145 0.14926878
>> 31 16611.604 0.11881219
>> 32 16511.736 0.092166908
>> 33 16197.967 0.069474578
>> 34 15683.489 0.050646842
>> 35 14993.074 0.035441618
>> 36 14154.316 0.023555880
>> 37 13197.065 0.014637120
>> 38 12152.937 0.082940198
>> 39 11054.853 0.041067102
>> 40 9936.6143 0.016359100
>> 41 8832.5371 0.0043106001
>> 42 7777.1499 0.00036969999
>> 43 6804.8740 0.0
>> 44 5937.0498 0.0
>> 45 5167.1460 0.0
>> 46 4485.4932 0.0
>> 47 3883.0520 0.0
>> 48 3351.4600 0.0
>> 49 2883.0381 0.0
>> 50 2470.7881 0.0
>> 51 2108.3660 0.0
>> 52 1790.0510 0.0
>> 53 1510.7111 0.0
>> 54 1265.7520 0.0
>> 55 1051.0800 0.0
>> 56 863.05798 0.0
>> 57 698.45697 0.0
>> 58 554.42401 0.0
>> 59 428.43399 0.0
>> 60 318.26599 0.0
>> 61 221.95799 0.0
>> 62 137.78999 0.0
>> 63 64.247002 0.0
>> 64 0.0 0.0
>>
>>
>> On Mon, Jun 4, 2018 at 2:33 PM, Matt Masarik <mattmasarik at boisestate.edu>
>> wrote:
>>
>>> I'm interested in plotting PV on isentropic surfaces from the NCEP CFSRR
>>> (reforecast) data set. I'm planning to interpolate variables to isentropes
>>> using (http://www.ncl.ucar.edu/Applications/Scripts/isent_1.ncl) and
>>> then calculate PV on those surfaces using (http://www.ncl.ucar.edu/Docum
>>> ent/Functions/Contributed/pot_vort_hybrid.shtml).
>>>
>>> A helper function in there (pres_hybrid_ccm) requires Hybrid A and
>>> Hybrid B coefficients for mid- model levels. I haven't been able to find
>>> anything for these constants in CFS on www.. Can someone point me to how I
>>> can find these?
>>>
>>> Thank you,
>>> Matt
>>>
>>> _______________________________________________
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>>
>
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