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wavedist

PURPOSE ^

WAVEDIST: estimates wind speed distortion due to surface waves.

SYNOPSIS ^

function [U10,delU]=wavedist(Ua,za,Hw)

DESCRIPTION ^

 WAVEDIST: estimates wind speed distortion due to surface waves.
 [U10,delU]=WAVEDIST(Ua,za,Hw) computes the true 10m wind speed U10
 using the wind speed Ua measured at the height za and measured wave 
 height Hw and the neutral log profile corrected for the effects of
 low-level distortion of the wind profile by surface waves following 
 Large, Morzel, and Crawford (1995), J. Phys. Ocean., 25, 2959-2971.
 
 INPUT:   Ua - wind speed  [m/s]
          za - wind measurement height  [m] 
          Hw - wave height  [m]

 OUTPUT:  U10 - true 10m wind speed  [m/s]
          delU - difference between true and uncorrected  
                  10m wind speed  [m/s]

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [U10,delU]=wavedist(Ua,za,Hw)
0002 % WAVEDIST: estimates wind speed distortion due to surface waves.
0003 % [U10,delU]=WAVEDIST(Ua,za,Hw) computes the true 10m wind speed U10
0004 % using the wind speed Ua measured at the height za and measured wave
0005 % height Hw and the neutral log profile corrected for the effects of
0006 % low-level distortion of the wind profile by surface waves following
0007 % Large, Morzel, and Crawford (1995), J. Phys. Ocean., 25, 2959-2971.
0008 %
0009 % INPUT:   Ua - wind speed  [m/s]
0010 %          za - wind measurement height  [m]
0011 %          Hw - wave height  [m]
0012 %
0013 % OUTPUT:  U10 - true 10m wind speed  [m/s]
0014 %          delU - difference between true and uncorrected
0015 %                  10m wind speed  [m/s]
0016 
0017 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0018 % 8/31/98: version 1.1
0019 % 8/5/99: version 2.0
0020 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0021 
0022 % get constants
0023 as_consts;
0024 
0025 tol=.001; % change in u10 to stop iteration
0026 
0027 zs=10;    % reference height
0028 
0029 Xia=za./Hw;Xis=zs./Hw;
0030 
0031 % compute uncorrected 10m wind speed and ustar (as initial guess in iteration)
0032 [cd10,u10]=cdnve(Ua,za);
0033 Ustar=sqrt(cd10).*u10;
0034 
0035 % compute corrected 10m wind speed
0036 U10=u10;
0037 U10o=0;
0038 k=0;
0039 while max(abs(U10-U10o))>tol & k<15,
0040   U10o=U10;
0041   k=k+1;
0042   Ustar=sqrt(cdnve(U10,10).*U10.^2);
0043   U10=Ua+Ustar.*(log(zs./za)-omegalmc(Xis)+omegalmc(Xia))./kappa;
0044 end
0045 
0046 if k==15,
0047  warning('Iteration may not have converged');
0048 end;
0049 
0050 delU=U10-u10;
0051 
0052

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