wavdist1

 WAVDIST1: estimates wave effects on wind speed measured at za.  
 Ut=WAVDIST1(Ua,za,Hw) computes the 'true' wind speed Ut at the
 measurement height za using the wind speed Ua measured at za and
 measured wave height Hw.
 
 INPUT:   Ua - wind speed  [m/s]
          za - wind measurement height  [m]
          Hw - wave height  [m]

 OUTPUT:  Ut - 'true' wind speed  [m/s]

0001 function Ut=wavdist1(Ua,za,Hw)
0002 % WAVDIST1: estimates wave effects on wind speed measured at za.
0003 % Ut=WAVDIST1(Ua,za,Hw) computes the 'true' wind speed Ut at the
0004 % measurement height za using the wind speed Ua measured at za and
0005 % measured wave height Hw.
0006 %
0007 % INPUT:   Ua - wind speed  [m/s]
0008 %          za - wind measurement height  [m]
0009 %          Hw - wave height  [m]
0010 %
0011 % OUTPUT:  Ut - 'true' wind speed  [m/s]
0012   
0013 % WAVDIST1 computes Ut from Ua using the neutral log profile corrected
0014 % for the effects of low-level distortion of the wind profile by surface
0015 % waves following Large, Morzel, and Crawford (1995), J. Phys. Oceanog.,
0016 % 25, 2959-2971.
0017  
0018 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0019 % 5/5/97: version 1.0
0020 % 7/28/99: version 1.1
0021 % 8/5/99: version 2.0
0022 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0023 
0024 k=0.4;
0025 z10=10;
0026 A=log(z10./za)./k;
0027 
0028 % eliminate any Ua==0
0029 jj=find(Ua==0);
0030 Ua(jj)=0.01.*ones(size(Ua(jj)));
0031 
0032 % compute uncorrected 10m wind speed
0033 u10=Ua; % initial guess
0034 for n=1:10;
0035   ustar=sqrt(cdnve(u10).*u10.^2);
0036   u10=Ua+ustar.*A;
0037 end
0038 
0039 % compute corrected 10m wind speed
0040 Ustar=ustar;U10=u10; % initial guesses
0041 Za=za./Hw;Z10=z10./Hw;
0042 for n=1:10;
0043   Ustar=sqrt(cdnve(U10).*U10.^2);
0044   U10=Ua+Ustar.*(log(z10./za)-omegalmc(Z10)+omegalmc(Za))./k;
0045 end
0046 
0047 % compute 'true' wind speed at za using U10, Ustar
0048 Ut=U10-Ustar.*A;
0049