## How to convert potential temperature to temperature

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Alex5
Posts: 12
Joined: Tue Oct 08, 2013 4:46 pm
Location: HongKong

### How to convert potential temperature to temperature

Dear all,

I want to calculate ocean heat content which is defined by temperature. Does anyone know how to convert potential temperature to temperature. Thanks.

Alex

wilkin
Posts: 526
Joined: Mon Apr 28, 2003 5:44 pm
Location: Rutgers University
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### Re: How to convert potential temperature to temperature

John Wilkin: DMCS Rutgers University
71 Dudley Rd, New Brunswick, NJ 08901-8521, USA. ph: 609-630-0559 jwilkin@rutgers.edu

fdaryabor
Posts: 78
Joined: Wed Jan 02, 2008 3:15 pm
Location: University of Copenhagen

### Re: How to convert potential temperature to temperature

Dear,

You can use the attachment file.

Attachments
sw_temp.m
sw_ptmp.m
the complementary function,

sw_ptmp: Potential temperature
sw_temp.m
sw_temp: Temperature from potential temperature

Alex5
Posts: 12
Joined: Tue Oct 08, 2013 4:46 pm
Location: HongKong

### Re: How to convert potential temperature to temperature

Thanks a lot. I will try them.

Alex5
Posts: 12
Joined: Tue Oct 08, 2013 4:46 pm
Location: HongKong

### Re: How to convert potential temperature to temperature

wilkin wrote:There is a "seawater" toolbox

in Matlab
http://www.cmar.csiro.au/datacentre/ext ... awater.htm

or Python
https://pypi.python.org/pypi/seawater/
Dear Wilkin,

Could I ask another question, why roms use potential temperature instead of temperature? Actually, I am very new to ocean model, I am wondering if the ocean models prefer potential temperature. Thanks.

Alex

wilkin
Posts: 526
Joined: Mon Apr 28, 2003 5:44 pm
Location: Rutgers University
Contact:

### Re: How to convert potential temperature to temperature

If you could put seawater in a container that insulates it from exchanging heat with any of the surrounding water, then move it from one depth to another, its temperature will change by virtue of the compression due to pressure. However, its potential temperature would not. That's basically the definition of potential temperature. So this is what we want in an ocean model - the model temperature only changes in response to heat exchange from surface fluxes or mixing with adjacent water of a different temperature. Just moving from one depth to another does nothing.
John Wilkin: DMCS Rutgers University
71 Dudley Rd, New Brunswick, NJ 08901-8521, USA. ph: 609-630-0559 jwilkin@rutgers.edu

Alex5
Posts: 12
Joined: Tue Oct 08, 2013 4:46 pm
Location: HongKong

### Re: How to convert potential temperature to temperature

wilkin wrote:If you could put seawater in a container that insulates it from exchanging heat with any of the surrounding water, then move it from one depth to another, its temperature will change by virtue of the compression due to pressure. However, its potential temperature would not. That's basically the definition of potential temperature. So this is what we want in an ocean model - the model temperature only changes in response to heat exchange from surface fluxes or mixing with adjacent water of a different temperature. Just moving from one depth to another does nothing.