# [talk-ph] Typhoon Wind Speeds

art esmeralda artesmeralda at gmail.com
Thu Dec 12 04:09:40 UTC 2013

```Good Effort Team Mark.

On Thu, Dec 12, 2013 at 3:15 AM, Mark Cupitt <markcupitt at gmail.com> wrote:

> Hi All
>
> Whilst looking at our areas and the overlaid track of the Typhoon, I was
> reminded of some information that I thought I would share with all
> concerned. I was reminded of this by one of our team members.
>
> In the Northern Hemisphere, Typhoons rotate in a Counter Clockwise
> Direction, so the actual wind on the ground has to be factored with the
> speed of travel of the typhoon itself. The faster the speed over ground of
> the typhoon, the more wind that will be added or subtracted over the ground
> depending on what position within the circulation a specific point is.
>
> To illustrate
>
> Typhoon is travelling East to West at 15 knots with wind speeds of 150
> knots.
> Because of the counter clockwise rotation, the actual winds North of the
> track will be wind-speed + the speed over ground of the typhoon, in our
> example, 150 + 15 = 165 knots
> On the south side of the track, it will be the reverse as we subtract the
> travel of the typhoon from the wind speed as it is travelling "with" the
> typhoon, in our example 150 - 15 = 135 knots.
> Now this may seem insignificant, but realize that the difference between
> the north side of the track and south side is actually 30 knots. This can
> make a significant difference in damage assessment.
>
> The strongest adjustments will be at 90 degrees to each side of the track
> with no adjustment on the actual track location itself, and proportionally
> in between the two positions.
>
> The Southern hemisphere is simply the reverse.
>
> When prioritizing mapping efforts, the initial areas to focus on would be
> 90 degrees to the north of the track in the Northern hemisphere and 90
> degrees south of track in the Southern Hemisphere to look for the areas
> with the most likely damage
>
> The faster the typhoon is travelling over the ground, the greater this
> effect is.
>
> Hope this is useful
>
> Regards
>
> Mark Cupitt
>
> "If we change the world, let it bear the mark of our intelligence"
>
>
> *See me on StackExchange <http://gis.stackexchange.com/users/17846/mark-c>*
>
>
> ===============================================================================================
> The contents of this email are intended only for the individual(s) to whom
> it is addressed and may contain
> confidential or privileged information. If you are not the intended
> recipient, you must not disclose, copy, distribute,
> or use the contents of this email. If you have received this email in
> error, please notify the sender immediately and
> delete the email and any attachments.
> ===============================================================================================
>
>
> _______________________________________________
> talk-ph mailing list
> talk-ph at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk-ph
>
>

--
Blessings,

Art Trillanes Esmeralda Jr

cell: +973. 369.55199
tetra: +973. 175.72819