Author: Aymeric SPIGA
The goal of this tutorial is to use PLANETOPLOT to compute (and plot) derivatives of a given field (say, temperature $T$).
-- Note that we make use here of the convenient planets library to get planetary constants. You can download and learn about here
First and foremost, import all the necessary librairies. Note that you need the ppcompute utility from PLANETOPLOT: derivatives functions are in this library.
In [88]:
from ppclass import pp
import ppplot
import ppcompute
import planets
import numpy as np
In [89]:
# This line configures matplotlib to show figures embedded in the notebook.
%matplotlib inline
Set up the planet and file to consider. Here we use the file used in the main PLANETOPLOT tutorial.
In [90]:
myplanet = planets.Mars
fff = "diagfired.nc"
Get the temperature field at a given time and zonally averaged
In [91]:
temp,lon,lat,z,t = pp(file=fff,var="temp",t=0.8,x="-180,180").getfd()
Convert degree to radian
In [92]:
phi = lat*np.pi/180.
sinphi = np.sin(phi)
cosphi = np.cos(phi)
Convert altitudes from km to m
In [93]:
z = z*1000.
Compute latitudinal & vertical derivatives using ppcompute
In [94]:
dTdphi,dTdz = ppcompute.deriv2d(temp,phi,z)
Plot with ppplot the meridional gradient of temperature as shaded field and temperature as contoured field
In [95]:
pl = ppplot.plot2d()
pl.f = dTdphi
pl.c = temp
pl.x = lat
pl.y = z
pl.ylabel = 'altitude (m)'
pl.xlabel = 'latitude ($^{\circ}$N)'
pl.title = '$dT/d\phi$'
pl.makeshow()
Compute the Brunt-Väisälä frequency
$$ N^2 = \frac{g}{T_0} \left( \frac{-g}{c_p} + \frac{\text{d}T}{\text{d}z} \right) $$
We use here the function defined in the planets library
In [96]:
bv = myplanet.N2(T0=temp,dTdz=dTdz)
Plot with ppplot the BV frequency as shaded field and temperature as contoured field. We can actually use the plot2d() object defined above since a bunch of settings are in common.
In [97]:
pl.f = bv
pl.title = '$N^2$'
pl.vmax = 2.e-4
pl.makeshow()