19.8. Advection

There are a number of different variables that could be advected in the atmosphere including temperature, moisture, vorticity, smoke, etc. Here we’ll demonstrate advection using temperature since it is a type of advection that is looked at very frequently and can have a large impact on what we experience as the weather changes. To begin the calculation, first isolate all of the variables you’ll need (e.g., temperature, u-component of the wind, and v-component of the wind) for the level and time you are computing. Then feed those variables into the calculation.

level = 850 * units.hPa
plot_time = date + timedelta(hours=0)

tmpk = ds.Temperature_isobaric.metpy.sel(vertical=level, time=plot_time)
uwind = ds['u-component_of_wind_isobaric'].metpy.sel(vertical=level, time=plot_time)
vwind = ds['v-component_of_wind_isobaric'].metpy.sel(vertical=level, time=plot_time)

ds['temperature_advection'] = mpcalc.advection(tmpk, uwind, vwind)

Advection Calculation Documentation

Advection can be scaled a couple of different ways, but generally we want to put it in terms of temperature per 3 hours. So, scaling by 10^4^ would approximately get you there.

Note

If you subset by time, set the time attribute to None.