Wind Barbs in the Southern Hemisphere

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weerman
Junior Member
Posts: 4
Joined: Thu Sep 02, 2004 10:26 am
Location: Aviation Weather Centre Johannesburg, South Africa

Wind Barbs in the Southern Hemisphere

Post by weerman »

Hi Guys

Something I haven't picked up, but was brought to my attention by my fellow forecasters is the direction of the wind barbs. :lol:

I know you guys in the Northern Hemisphere would not have picked this up, since it is correct Northern Hemispheric barbs, but in the Southern Hemisphere the barb should be the other way around.

I hope this reaches Jeff in time to consider fixing it in his next update.

Regards

Quinton

jkrob
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Post by jkrob »

Quinton,

Thanks for the heads-up. I'll look into it. Just to make sure we are clear, for an east-to-west wind, all barb flags should be pointing tward the south, reguardless of hemisphere?

Thanks,
Jeff

jkrob
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Post by jkrob »

Quinton (and anyone else wishing to join in),

I found the issue with the wind barbs & the fix is no problem. The only thing is I found the bug back in the origional PCGRIDDS code. Has this problem been there all along? I guess the program should follow the WMO standard but I'm not sure what that is. As far as I'm concerned, it can go either way but I think it needs to be right. I just find it odd it has been this way for this long. All of my systems are now Win 2k so I can't run DOS PCGRIDDS to check on it. If there are other international/southern hemisphere users who wish to contribute on the issue, I'm all ears.

Thanks in advance,
Jeff

weerman
Junior Member
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Joined: Thu Sep 02, 2004 10:26 am
Location: Aviation Weather Centre Johannesburg, South Africa

Reply on Barb Winds

Post by weerman »

Hi Guys.

Yes Jeff, the barbs should point polewards if the flow is zonal. In the DOS version of PCGridds the barbs is right, that is why some of our forecasters notice it. I myself is not too concern about it, I feel if the barb at least indicate the right speed it's okay, but some people find it strange.

I know that we are probably the only people who would've picked up this problem, since PCGridds is mainly used in the Northern Hemisphere where this problem wouldn't be noticed.

Regards

Quinton

jkrob
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Post by jkrob »

Quinton,

Please check this out in DOS PCGRIDDS; If you have a WAFS or other file which covers the southern hemisphere, do the command ALAT. Please see if the latitude numbers are displayed positive or negative value. This could be the key to the issue...I have a theory.

Thanks in advance,
Jeff

weerman
Junior Member
Posts: 4
Joined: Thu Sep 02, 2004 10:26 am
Location: Aviation Weather Centre Johannesburg, South Africa

Post by weerman »

Hi Guys

Sorry it took so long to reply, but I was on leave for a week.

Jeff, I tried the ALAT command on both versions of PCGridds and both gives the latitudes as negative.

Regards
Quinton

jkrob
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Posts: 300
Joined: Fri Jun 25, 2004 11:42 pm
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Post by jkrob »

Quinton,

OK...shoots that theory :? I have the bug fixed anyway. Release with that bug fix as well as a few others will be out shortly.

This bug has been there all along???

Thanks again,
Jeff

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