Potential temperature advection

[fherreazcue]

Calculate and plot 925-hPa, 850-hPa, 700-hPa, 500-hPa, and 300-hPa potential temperature advection (–V · [Delta][theta]) for the Control case. Ensure a clear break in the color scheme at zero (blue for cold advection, and red for warm advection; equal ranges on both sides of zero). Overlay potential temperature in 2 K intervals solid lines and wind barbs.

[douglowe]

Information from Dave:

---

Potential temperature advection equals minus velocity vector dot grad potential temperature.

https://earthscience.stackexchange.com/questions/16527/temperature-advection-using-finite-differences-with-gridded-data

If you are in SI units, then multiply by 24*3600, so that the units are K/day.

---

and a clarification:

---

I should mention this is the horizontal wind and the 2D grad operator.

Just horizontal potential temperature advection, please.

---

[douglowe]

And, from the stackexchange article, it looks like there's a metpy function to do what we need: https://unidata.github.io/python-gallery/examples/850hPa_Temperature_Advection.html