gsw_adiabatic_lapse_rate_ice.m

function adiabatic_lapse_rate_ice = gsw_adiabatic_lapse_rate_ice(t,p)

% gsw_adiabatic_lapse_rate_ice                         adiabatic lapse rate
%==========================================================================
%
% USAGE:
%  adiabatic_lapse_rate_ice = gsw_adiabatic_lapse_rate_ice(t,p)
%
% DESCRIPTION:
%  Calculates the adiabatic lapse rate of ice.
%
% INPUT:
%  t  =  in-situ temperature (ITS-90)                             [ deg C ]
%  p  =  sea pressure                                              [ dbar ]
%         ( i.e. absolute pressure - 10.1325 dbar ) 
%
%  p may have dimensions 1x1 or Mx1 or 1xN or MxN, where t is MxN.
%
% OUTPUT:
%  adiabatic_lapse_rate_ice  =  adiabatic lapse rate               [ K/Pa ]
%    Note.  The output is in unit of degress Celsius per Pa,
%      (or equivilently K/Pa) not in units of K/dbar. 
%
% AUTHOR: 
%  Paul Barker and Trevor McDougall                    [ help@teos-10.org ]
%      
% VERSION NUMBER: 3.05 (27th January 2015)
%
% REFERENCES:
%  IOC, SCOR and IAPSO, 2010: The international thermodynamic equation of 
%   seawater - 2010: Calculation and use of thermodynamic properties.  
%   Intergovernmental Oceanographic Commission, Manuals and Guides No. 56,
%   UNESCO (English), 196 pp.  Available from http://www.TEOS-10.org.
%
%  The software is available from http://www.TEOS-10.org
%
%==========================================================================

%--------------------------------------------------------------------------
% Check variables and resize if necessary
%--------------------------------------------------------------------------

if ~(nargin == 2) 
   error('gsw_adiabatic_lapse_rate_ice:  Requires two inputs')
end

[mt,nt] = size(t);
[mp,np] = size(p);

if (mp == 1) & (np == 1)              % p scalar - fill to size of t
    p = p*ones(size(t));
elseif (nt == np) & (mp == 1)         % p is row vector,
    p = p(ones(1,mt), :);              % copy down each column.
elseif (mt == mp) & (np == 1)         % p is column vector,
    p = p(:,ones(1,nt));               % copy across each row.
elseif (nt == mp) & (np == 1)          % p is a transposed row vector,
    p = p.';                              % transposed then
    p = p(ones(1,mt), :);                % copy down each column.
elseif (mt == mp) & (nt == np)
    % ok
else
    error('gsw_adiabatic_lapse_rate_ice: Inputs array dimensions arguments do not agree')
end %if

if mt == 1
    t = t.';
    p = p.';
    transposed = 1;
else
    transposed = 0;
end

%--------------------------------------------------------------------------
% Start of the calculation
%--------------------------------------------------------------------------

adiabatic_lapse_rate_ice = -gsw_gibbs_ice(1,1,t,p)./(gsw_gibbs_ice(2,0,t,p));

if transposed
    adiabatic_lapse_rate_ice = adiabatic_lapse_rate_ice.';
end

end