Vector arrows for primary wave direction

[Nathan Cool]

Thanks, but I'm not trying to display "wind" vector arrows; instead, I'm
trying to display the primary wave direction.

The vars in the Grib are:
------------------------
DIRPWsfc  0 107,1,1  ** surface Primary wave direction [deg]
DIRSWsfc  0 109,1,1  ** surface Secondary wave direction [deg]
HTSGWsfc  0 100,1,1  ** surface Sig height of wind waves and swell [m]
PERPWsfc  0 108,1,1  ** surface Primary wave mean period [s]
PERSWsfc  0 110,1,1  ** surface Secondary wave mean period [s]
UGRDsfc  0 33,1,1  ** surface u wind [m/s]
VGRDsfc  0 34,1,1  ** surface v wind [m/s]
WDIRsfc  0 31,1,1  ** surface Wind direction [deg]
WINDsfc  0 32,1,1  ** surface Wind speed [m/s]
WVDIRsfc  0 101,1,1  ** surface Direction of wind waves [deg]
WVPERsfc  0 103,1,1  ** surface Mean period of wind waves [s]

...and I can see that others have been able to show the primary wave
direction (DIRPWsfc) using vector arrows, as is the case on the FNMOC models
like this one:
https://www.fnmoc.navy.mil/ww3_cgi/dynamic/ww3.w.npac.sig_wav_ht.000.gif

Do you know how this can be done?

Thanks,

-Nathan


On Tue, Nov 3, 2009 at 9:58 PM, sushant puranik <sushantpuranik at gmail.com>wrote:

> Hi
> I am able to generate wind direction. try his
> 'set arrscl 1 30'
> 'set cthick 5'
> 'set arrowhead 0.10'
> 'set clevs 3 5 10 15 20 25'
> 'set ccols 0 4 1 2 3 5 12'
> 'set gxout vector'
> 'd
> skip(UGRDsfc,2,2);skip(VGRDsfc,2,2);skip(sqrt(UGRDsfc*UGRDsfc+VGRDsfc*VGRDsfc),2,2)'
> 'run cbar.gs'
> 'printim wind(m/s)'
>
> with the help of such script i am able to generate output which is attached
> with this mail.
>
> all the best.
>
>
> On Tue, Nov 3, 2009 at 9:45 PM, Nathan Cool <nathan at nathancool.com> wrote:
>
>> Good morning everyone,
>>
>> I'm generating wave analysis models, but I'm having a tough time showing
>> the mean-wave (or primary) wave direction arrows.
>>
>> The vars in the Grib are:
>> -------------------------------------------------
>> DIRPWsfc  0 107,1,1  ** surface Primary wave direction [deg]
>> DIRSWsfc  0 109,1,1  ** surface Secondary wave direction [deg]
>> HTSGWsfc  0 100,1,1  ** surface Sig height of wind waves and swell [m]
>> PERPWsfc  0 108,1,1  ** surface Primary wave mean period [s]
>> PERSWsfc  0 110,1,1  ** surface Secondary wave mean period [s]
>> UGRDsfc  0 33,1,1  ** surface u wind [m/s]
>> VGRDsfc  0 34,1,1  ** surface v wind [m/s]
>> WDIRsfc  0 31,1,1  ** surface Wind direction [deg]
>> WINDsfc  0 32,1,1  ** surface Wind speed [m/s]
>> WVDIRsfc  0 101,1,1  ** surface Direction of wind waves [deg]
>> WVPERsfc  0 103,1,1  ** surface Mean period of wind waves [s]
>>
>> For displaying wind vector arrows it's straightforward as there are U and
>> V variables (UGRDsfc and VGRDsfc) for the zonal and meridional components.
>> Displaying primary wave direction though seems more elusive, yet I see it
>> done on many models such as the following:
>> https://www.fnmoc.navy.mil/ww3_cgi/dynamic/ww3.w.npac.sig_wav_ht.000.gif
>>
>> ...which was generated using GrADS by FNMOC.
>>
>> Any help you can provide would be greatly appreciated, and thank you for
>> your time.
>>
>> --
>> Nathan Cool
>> nathan at nathancool.com
>>
>
>
>
> --
> Sushant Puranik
> Junior Research Fellow
> Dept. of Atmospheric & Space Sciences,
> University of Pune,
> Pune-07,
> India.
>
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