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miecoated_rain5

PURPOSE ^

Freezing rain

SYNOPSIS ^

function result = miecoated_rain5(coat, R, TK, fmin, fmax, nfreq)

DESCRIPTION ^

 Freezing rain
 Extinction, scattering, absorption, backscattering and 
 asymmetric scattering coefficients in 1/km for Marshall-Palmer 
 (MP) drop-size distribution (Sauvageot et al. 1992), versus 
 frequency of ice-coated water spheres (freezing rain)
 with constant thickness 'coat' of the coating, using Mie Theory,
 the dielectric model of Liebe et al. 1991 for water and
 of M�zler (1998) for ice.
 Input:
 coat: thickness of coating in mm, 
 R: rain rate in mm/h, TK: Temp. in K, 
 fmin, fmax: minimum and maximum frequency in GHz
 nfreq: Number of frequencies 
 C. M�zler, June 2002.

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

DOWNLOAD ^

miecoated_rain5.m

SOURCE CODE ^

0001 function result = miecoated_rain5(coat, R, TK, fmin, fmax, nfreq)
0002 
0003 % Freezing rain
0004 % Extinction, scattering, absorption, backscattering and
0005 % asymmetric scattering coefficients in 1/km for Marshall-Palmer
0006 % (MP) drop-size distribution (Sauvageot et al. 1992), versus
0007 % frequency of ice-coated water spheres (freezing rain)
0008 % with constant thickness 'coat' of the coating, using Mie Theory,
0009 % the dielectric model of Liebe et al. 1991 for water and
0010 % of M�zler (1998) for ice.
0011 % Input:
0012 % coat: thickness of coating in mm,
0013 % R: rain rate in mm/h, TK: Temp. in K,
0014 % fmin, fmax: minimum and maximum frequency in GHz
0015 % nfreq: Number of frequencies
0016 % C. M�zler, June 2002.
0017 
0018 opt=1
0019 nsteps=501;                  % number of drop-diameter values
0020 N0=0.08/10000;               % original MP N0 in 1/mm^4
0021 fact=(fmax/fmin)^(1/(nfreq-0.99999));
0022 fGHz=fmin/fact;
0023 nx=(1:nsteps)';
0024 c0=299.793;
0025 for jr = 1:nfreq
0026     fGHz=fGHz*fact;
0027     m1=sqrt(epswater(fGHz, TK));
0028     m2=sqrt(epsice(fGHz, TK));
0029     dD=0.01*R^(1/6)/fGHz^0.05;
0030     D=(nx-0.5)*dD;
0031     y=pi*D*fGHz/c0;
0032     dxcoat=2*pi*coat.*fGHz/c0;
0033     x=max(0,y-dxcoat);
0034     sigmag=pi*D.*D/4;
0035     LA=4.1/R^0.21;
0036     NMP=N0*exp(-LA*D);       % MP distribution
0037     sn=sigmag.*NMP*1000000;
0038     for j = 1:nsteps    
0039         a(j,:)=miecoated(m1,m2,x(j),y(j),opt);
0040     end;
0041     b(:,1)=D;             b(:,2)=a(:,1).*sn;   
0042     b(:,3)=a(:,2).*sn;    b(:,4)=a(:,3).*sn;
0043     b(:,5)=a(:,4).*sn;   b(:,6)=a(:,2).*a(:,5).*sn; 
0044     gext= sum(b(:,2))*dD;    gsca= sum(b(:,3))*dD;
0045     gabs= sum(b(:,4))*dD;    gb=   sum(b(:,5))*dD;
0046     gteta=sum(b(:,6))*dD;
0047     res(jr,:)=[fGHz gext gsca gabs gb gteta];
0048 end;
0049 output_parameters='Gext, Gsca, Gabs, Gb, Gsca<costeta>'
0050 plot(res(:,1),res(:,2:6))
0051 legend('Gext','Gsca','Gabs','Gb','Gsca<costeta>')
0052 title(sprintf('Ice-Coated Rain Coefficients vs. Frequency at R=%gmm/h, T=%gK, coat=%gmm',R,TK,coat))
0053 xlabel('f (GHz)');    ylabel('Gi(1/km)')
0054 result=res;

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