hybrid sigma-pressure levels to altitude in meters
hybrid sigma-pressure levels to altitude in meters
Is there a way (formula) to convert hybrid sigma-pressure levels to altitude in meters? What I am trying to do is to get wind direction and speed at certain height (meters) from file *gdas0p5.
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Re: hybrid sigma-pressure levels to altitude in meters
The program profile.F should help you get the variables profiles as a function of height.
Re: hybrid sigma-pressure levels to altitude in meters
I only have executable profile.exe where I can find source code to edit it and compile? Is there any documentation on the format of gdas files so I can write my program to extract desired values at desired height and long and lat?ariel.stein wrote:The program profile.F should help you get the variables profiles as a function of height.
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Re: hybrid sigma-pressure levels to altitude in meters
As a start, you could run the executable and see if it meets your needs
Re: hybrid sigma-pressure levels to altitude in meters
so I tried and it gave the variables profiles as a function of pressure, how to convert pressure to height in meters?ariel.stein wrote:The program profile.F should help you get the variables profiles as a function of height.
Code: Select all
PRSS MSLE UMOF VMOF TPP6 SHTF DSWF SPH2 U10M V10M T02M TCLD PBLH LHTF USTR RGHS PTRO
hPa mm W/m2 W/m2 m/s m/s oC % m W/m2 cm/s m
970 970 1016 3E-2 1E-1 0 118 613 1E-2 -1.6 -4.6 25.1 0 1202 32.0 28.9 1E-1 109
3D Fields
TEMP UWND VWND WWND SPHU PRES TPOT UWND VWND
oC m/s m/s mb/h g/kg oK W->E S->N
970 24.4 -1.3 -4.0 0 7.3 969 300.3 -1.3 -4.0
965 23.7 -1.2 -4.8 -2.9 7.3 965 299.9 -1.2 -4.8
959 23.2 -1.6 -4.5 -3.0 7.1 956 300.1 -1.6 -4.5
953 22.4 -1.6 -4.3 0 7.1 951 299.8 -1.6 -4.3
and so on..
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Re: hybrid sigma-pressure levels to altitude in meters
The gdas 0.5 degree dataset has the following 55 hybrid sigma-pressure Levels
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0.9999, 0.9947, 0.9886, 0.9817, 0.9739,
1.9648, 1.9544, 2.9425, 4.9288, 6.9132,
8.8954, 11.875, 16.853, 21.827, 26.799,
33.769, 41.735, 49.699, 59.660, 69.619,
80.576, 91.531, 102.49, 113.44, 123.39,
133.35, 143.30, 151.26, 157.22, 162.18,
165.15, 166.12, 165.09, 162.07, 157.05,
150.04, 142.02, 132.01, 122.01, 111.00,
99.002, 88.000, 78.000, 68.000, 59.000,
52.000, 45.000, 39.000, 34.000, 29.000,
25.000, 21.000, 18.000, 15.000, 13.000
A pressure level is defined as: P = A + 0.B*PRSS,
where PRSS is the surface pressure and A.B is defined as the level, so for instance for level 13: A.B=16.853; A=16 and B=853 ; then P = 16+0.853*PRSS
Finally you can take the pressure levels and use the hypsometric equation and get the equivalent height.
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0.9999, 0.9947, 0.9886, 0.9817, 0.9739,
1.9648, 1.9544, 2.9425, 4.9288, 6.9132,
8.8954, 11.875, 16.853, 21.827, 26.799,
33.769, 41.735, 49.699, 59.660, 69.619,
80.576, 91.531, 102.49, 113.44, 123.39,
133.35, 143.30, 151.26, 157.22, 162.18,
165.15, 166.12, 165.09, 162.07, 157.05,
150.04, 142.02, 132.01, 122.01, 111.00,
99.002, 88.000, 78.000, 68.000, 59.000,
52.000, 45.000, 39.000, 34.000, 29.000,
25.000, 21.000, 18.000, 15.000, 13.000
A pressure level is defined as: P = A + 0.B*PRSS,
where PRSS is the surface pressure and A.B is defined as the level, so for instance for level 13: A.B=16.853; A=16 and B=853 ; then P = 16+0.853*PRSS
Finally you can take the pressure levels and use the hypsometric equation and get the equivalent height.