initial

Convenience routines for setting up initial conditions.

climlab.domain.initial.column_state(num_lev=30, num_lat=1, lev=None, lat=None, water_depth=1.0)[source]

Sets up a state variable dictionary consisting of temperatures for atmospheric column (Tatm) and surface mixed layer (Ts).

Surface temperature is always 288 K. Atmospheric temperature is initialized between 278 K at lowest altitude and 200 at top of atmosphere according to the number of levels given.

Function-call arguments

Parameters
  • num_lev (int) – number of pressure levels (evenly spaced from surface to top of atmosphere) [default: 30]

  • num_lat (int) – number of latitude points on the axis [default: 1]

  • lev (Axis or pressure array) – specification for height axis (optional)

  • lat (array) – size of array determines dimension of latitude (optional)

  • water_depth (float) – irrelevant

Returns

dictionary with two temperature Field for atmospheric column Tatm and surface mixed layer Ts

Return type

dict

Example
>>> from climlab.domain import initial
>>> T_dict = initial.column_state()

>>> print T_dict
{'Tatm': Field([ 200.        ,  202.68965517,  205.37931034,  208.06896552,
        210.75862069,  213.44827586,  216.13793103,  218.82758621,
        221.51724138,  224.20689655,  226.89655172,  229.5862069 ,
        232.27586207,  234.96551724,  237.65517241,  240.34482759,
        243.03448276,  245.72413793,  248.4137931 ,  251.10344828,
        253.79310345,  256.48275862,  259.17241379,  261.86206897,
        264.55172414,  267.24137931,  269.93103448,  272.62068966,
        275.31034483,  278.        ]), 'Ts': Field([ 288.])}
climlab.domain.initial.surface_state(num_lat=90, num_lon=None, water_depth=10.0, T0=12.0, T2=-40.0)[source]

Sets up a state variable dictionary for a surface model (e.g. EBM) with a uniform slab ocean depth.

The domain is either 1D (latitude) or 2D (latitude, longitude) depending on whether the input argument num_lon is supplied.

Returns a single state variable Ts, the temperature of the surface mixed layer (slab ocean).

The temperature is initialized to a smooth equator-to-pole shape given by

\[T(\phi) = T_0 + T_2 P_2(\sin\phi)\]

where \(\phi\) is latitude, and \(P_2\) is the second Legendre polynomial P2.

Function-call arguments

Parameters
  • num_lat (int) – number of latitude points [default: 90]

  • num_lat – (optional) number of longitude points [default: None]

  • water_depth (float) – depth of the slab ocean in meters [default: 10.]

  • T0 (float) – global-mean initial temperature in \(^{\circ} \textrm{C}\) [default: 12.]

  • T2 (float) – 2nd Legendre coefficient for equator-to-pole gradient in initial temperature, in \(^{\circ} \textrm{C}\) [default: -40.]

Returns

dictionary with temperature Field for surface mixed layer Ts

Return type

dict

Example
>>> from climlab.domain import initial
>>> import numpy as np

>>> T_dict = initial.surface_state(num_lat=36)

>>> print np.squeeze(T_dict['Ts'])
[-27.88584094 -26.97777479 -25.18923361 -22.57456133 -19.21320344
 -15.20729309 -10.67854785  -5.76457135  -0.61467228   4.61467228
   9.76457135  14.67854785  19.20729309  23.21320344  26.57456133
  29.18923361  30.97777479  31.88584094  31.88584094  30.97777479
  29.18923361  26.57456133  23.21320344  19.20729309  14.67854785
   9.76457135   4.61467228  -0.61467228  -5.76457135 -10.67854785
 -15.20729309 -19.21320344 -22.57456133 -25.18923361 -26.97777479
 -27.88584094]