Re: [ferret_users] conversion of decibars to metre depth in sea water

To: ferret users <ferret_users@xxxxxxxx>

Subject: Re: [ferret_users] conversion of decibars to metre depth in sea water

From: Ryo Furue <furue@xxxxxxxxxx>

Date: Fri, 3 Mar 2017 14:16:34 +0900

Cc: Russ Fiedler <russell.fiedler@xxxxxxxx>

Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=noaa-gov.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:x-original-sender:x-original-authentication-results:precedence :mailing-list:list-id:list-post:list-help:list-archive :list-unsubscribe; bh=f196FCoZ2yOhm6YK9bpdXVoGtcrDW1ValbnMvvid7Do=; b=Q10sa5oXIadEI/XeGc4AeZD66nS+RwvS3gR0YrQyOsvO2vx8yQkHl+LXMu2rCyIAQX P3iLhO49V76R2JHmWKJvEjMYkwpuKpi/AVODrXjY/TQ6Td84ClOBCkESAUaOLt1iTWFK chDNj1Wy6utW85yw7fJtZbKxZCBbhvOKqZa+XP6vMsJXThZPIHMCQevAA2ZM8daLG3Zu 4RUKjD7VENHDcwTwf0UQ0m8q/Eo37AgwIqOL2lEY33slCTkwBuOGe3w+WQqYTU/CtCvO gtq6MdSAOqnGSpCzPQTT6I29IE0DXa68JrpL8moBQY77y39aodOYVJYtyXQUNLEYijtx CiNg==

In-reply-to: <0f53b08b-a360-0445-2c0b-f4da12444083@csiro.au>

List-archive: <https://groups.google.com/a/noaa.gov/group/ferret_users/>

List-help: <https://support.google.com/a/noaa.gov/bin/topic.py?topic=25838>, <mailto:ferret_users+help@noaa.gov>

List-id: <ferret_users.noaa.gov>

List-post: <https://groups.google.com/a/noaa.gov/group/ferret_users/post>, <mailto:ferret_users@noaa.gov>

List-unsubscribe: <mailto:googlegroups-manage+809428289204+unsubscribe@googlegroups.com>, <https://groups.google.com/a/noaa.gov/group/ferret_users/subscribe>

Mailing-list: list ferret_users@xxxxxxxx; contact ferret_users+owners@xxxxxxxx

References: <CAFXLzPizS1oSa=q0wDZHWayK7pTwxtcqgyPyMTWPXgeutAu_PA@mail.gmail.com> <0f53b08b-a360-0445-2c0b-f4da12444083@csiro.au>

Sender: owner-ferret_users@xxxxxxxx

Hi Saurabh and Russ,

On Fri, Mar 3, 2017 at 11:34 AM, Russ Fiedler <russell.fiedler@xxxxxxxx> wrote:

You'll need the density information in order to integrate 1/(g*rho) from the surface downwards and then use ZAXREPLACE to map to the z axis.
If you have the salinity information then use the function RHO_UN.

But, very often, we don't need that accuracy. Usually pressure in decibars is regarded as equivalent to depth in meters. We had the same discussion in the mid January:

http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_2017/msg00034.html

The thread also describes more accurate conversions.

Ryo