lovenums.m

function [lkli,lkl]=lovenums(mod,els)
% [lkli,lkl]=LOVENUMS(mod,els)
%
% Returns a set of Love numbers. Intermediate numbers can be linearly
% interpolated with  errors of less than 0.05% for all l<200, as opposed
% to direct calculation. See Wahr et al. (1998) and Han & Wahr (1995).
%
% INPUT:
%
% mod   'Wahr' Wahr et al. (1998) after Han & Wahr (1995) after PREM.
% els   The spherical harmonic degrees where you want them
%
% OUTPUT:
%
% lkli   The spherical harmonic degrees l under consideration and k_l, 
%        the elastic Love numbers in PREM, linearly interpolated from:
% lkl    The original table from the model specified as the mod input.
%
% Last modified by fjsimons-at-alum.mit.edu, 12/10/2021
% Last modified by charig-at-princeton.edu, 11/08/2013

% Only one option, really
defval('mod','Wahr')

switch mod
 case 'Wahr'
  % Note: in the Wahr et al. (1998) paper the Love number for degree one is
  % reported as 0.027. However, since we use this conversion mostly with
  % GRACE data, we have changed the number for degree 1 to be 0.021. This is
  % the reported value for using the degree one coefficients from Swenson et
  % al. (2008). See:
  % ftp://podaac.jpl.nasa.gov/allData/tellus/L2/degree_1/deg1_coef.txt
  lkl=[0    0.000;
       1    0.021; % 0.027;
       2   -0.303;
       3   -0.194;
       4   -0.132;
       5   -0.104;
       6   -0.089;
       7   -0.081;
       8   -0.076;
       9   -0.072;
       10  -0.069;
       12  -0.064;
       15  -0.058;
       20  -0.051;
       30  -0.040;
       40  -0.033;
       50  -0.027;
       70  -0.020;
       100 -0.014;
       150 -0.010;
       200 -0.007];
 otherwise
  error('Specify valid Love number table')
end

if max(els) > 200
  lkl = [lkl; 500 0];
  disp('Caution: degrees above have been crudely estimated.')
end

% Now interpolate to where you want them
lkli=[els(:) interp1(lkl(:,1),lkl(:,2),els(:))];