ST_erate

 Calculate erosion rate in kg/(m^2-s)

 function [erate] = ST_erate(d,varargin)

 DESCRIPTION:
 Calculate erosion rate of sediment diameter d (m) in kg/(m^2-s)
   See NOTE below

 INPUT:
    d: sediment grain size in m
    [optional] 'temperature' = temperature of the seawater in C [default=10]
    [optional] 'salinity'    = salinity of seawater in PSU      [default=35]
    [optional] 'sdens'       = sediment density in kg/m^3       [default=2650]

 OUTPUT:
    erate in kg/(m^2-s)

 EXAMPLE USAGE
    erate = ST_erate(.0005,'temperature',10,'salinity',35,'sdens',2650) 

 Author(s):  
    Geoff Cowles (University of Massachusetts Dartmouth)

 References
    Blaas etal, Cont. Shelf. Res., 27, 2007

 Note
    THIS CALCULATION IS A HACK BASED ON A CURVE FIT OF SEVERAL STUDIES
    Need to modify to use formula of Drake and Cacchione, CSR 9, 1989
    or other.  Someone fix this if possible.

 Revision history
   
==============================================================================

0001 function [erate] = ST_erate(d,varargin)
0002 % Calculate erosion rate in kg/(m^2-s)
0003 %
0004 % function [erate] = ST_erate(d,varargin)
0005 %
0006 % DESCRIPTION:
0007 % Calculate erosion rate of sediment diameter d (m) in kg/(m^2-s)
0008 %   See NOTE below
0009 %
0010 % INPUT:
0011 %    d: sediment grain size in m
0012 %    [optional] 'temperature' = temperature of the seawater in C [default=10]
0013 %    [optional] 'salinity'    = salinity of seawater in PSU      [default=35]
0014 %    [optional] 'sdens'       = sediment density in kg/m^3       [default=2650]
0015 %
0016 % OUTPUT:
0017 %    erate in kg/(m^2-s)
0018 %
0019 % EXAMPLE USAGE
0020 %    erate = ST_erate(.0005,'temperature',10,'salinity',35,'sdens',2650)
0021 %
0022 % Author(s):
0023 %    Geoff Cowles (University of Massachusetts Dartmouth)
0024 %
0025 % References
0026 %    Blaas etal, Cont. Shelf. Res., 27, 2007
0027 %
0028 % Note
0029 %    THIS CALCULATION IS A HACK BASED ON A CURVE FIT OF SEVERAL STUDIES
0030 %    Need to modify to use formula of Drake and Cacchione, CSR 9, 1989
0031 %    or other.  Someone fix this if possible.
0032 %
0033 % Revision history
0034 %
0035 %==============================================================================
0036 
0037 subname = 'ST_erate';  
0038 %fprintf('\n')
0039 %fprintf(['begin : ' subname '\n'])
0040 
0041 % constants
0042 grav  = 9.8106;   %g
0043 T     = 10;       %T (C)
0044 S     = 35;       %S (PSU)
0045 sdens = 2650;     %sediment density in kg/m^3
0046 
0047 % parse arguments
0048 for i=1:2:length(varargin)-1
0049         keyword  = lower(varargin{i});
0050         if( ~ischar(keyword) )
0051                 error('incorrect usage of ST_wset')
0052         end;
0053 
0054         switch(keyword(1:3))
0055 
0056         case 'tem'
0057              T = varargin{i+1};
0058         case 'sal'
0059              S = varargin{i+1};
0060         case 'sde'
0061              sdens = varargin{i+1}; 
0062         otherwise
0063                 error(['Can''t understand value for:' keyword]);
0064         end; %switch keyword
0065 end;
0066 
0067 % calculate settling velocity
0068 wset = ST_wset(d,'temperature',T,'salinity',S,'sdens',sdens);
0069 
0070 % calculate erosion rate
0071 erate = 2.666e-4*wset*1000. - 2.51e-9*sdens;
0072 
0073 
0074 
0075 %fprintf(['end   : ' subname '\n'])