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miecoated_rain6

PURPOSE ^

Extinction, scattering, absorption, backscattering and

SYNOPSIS ^

function result = miecoated_rain6(fGHz, R, TK)

DESCRIPTION ^

 Extinction, scattering, absorption, backscattering and 
 asymmetric scattering coefficients in 1/km for Marshall-Palmer 
 (MP) drop-size distribution (Sauvageot et al. 1992),
 versus thickness 'coat' of water-coated ice spheres (melting ice)
 assuming coat=min(coat,radius) for all spheres, using Mie Theory,
 the dielectric model of Liebe et al. 1991 for water and
 of M�zler (1998) for ice.
 Input:
 fGHz: frequency in GHz, R: rain rate in mm/h, TK: Temp. in K
 C. M�zler, July 2002.

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

DOWNLOAD ^

miecoated_rain6.m

SOURCE CODE ^

0001 function result = miecoated_rain6(fGHz, R, TK)
0002 
0003 % Extinction, scattering, absorption, backscattering and
0004 % asymmetric scattering coefficients in 1/km for Marshall-Palmer
0005 % (MP) drop-size distribution (Sauvageot et al. 1992),
0006 % versus thickness 'coat' of water-coated ice spheres (melting ice)
0007 % assuming coat=min(coat,radius) for all spheres, using Mie Theory,
0008 % the dielectric model of Liebe et al. 1991 for water and
0009 % of M�zler (1998) for ice.
0010 % Input:
0011 % fGHz: frequency in GHz, R: rain rate in mm/h, TK: Temp. in K
0012 % C. M�zler, July 2002.
0013 
0014 opt=1;
0015 nsteps=201;                  % number of drop-diameter values optimized for MP
0016 LA=4.1/R^0.21;               % MP paramter (with size unit in mm)
0017 N0=0.08/10000;               % original MP N0 in 1/mm^4
0018 nx=(1:nsteps)';
0019 c0=299.793;
0020 m2=sqrt(epswater(fGHz, TK)); % refractive index of pure water
0021 m1=sqrt(epsice(fGHz, TK));   % refractive index of pure ice
0022 dD=0.025*R^(1/6)/fGHz^0.05;   % diameter interval optimized for MP
0023 D=(nx-0.5)*dD;               % drop diameter in mm
0024 y=pi*D*fGHz/c0;
0025 coa=[0.,0.000001,0.000003,0.00001,0.00003,0.0001,0.0003,0.001,0.002,0.004,0.008,0.012,0.02,0.03,0.05,0.08,0.12,0.18,0.27,0.38,0.60,0.75,1];
0026 for jr = 1:23
0027     dx=2*pi*coa(jr)*fGHz/c0;
0028     x=max(y-dx,0);
0029     coat=dx*c0/(2*pi*fGHz);
0030     sigmag=pi*D.*D/4;        % geometric cross section
0031     NMP=N0*exp(-LA*D);       % MP distribution
0032     sn=sigmag.*NMP*1000000;  
0033     for j = 1:nsteps    
0034         a(j,:)=miecoated(m1,m2,x(j),y(j),opt);
0035     end;
0036     b(:,1)=D;             b(:,2)=a(:,1).*sn;   
0037     b(:,3)=a(:,2).*sn;    b(:,4)=a(:,3).*sn;
0038     b(:,5)=a(:,4).*sn;   b(:,6)=a(:,2).*a(:,5).*sn; 
0039     gext= sum(b(:,2))*dD;    gsca= sum(b(:,3))*dD;
0040     gabs= sum(b(:,4))*dD;    gb=   sum(b(:,5))*dD;
0041     gteta=sum(b(:,6))*dD;
0042     res(jr,:)=[coat gext gsca gabs gb gteta];
0043 end;
0044 output_parameters='Gext, Gsca, Gabs, Gb, Gsca<costeta>'
0045 loglog(res(:,1),res(:,2:6))
0046 legend('Gext','Gsca','Gabs','Gb','Gsca<costeta>)')
0047 title(sprintf('Melting ice rain at R=%gmm/h, T=%gK, f=%gGHz',R,TK,fGHz))
0048 xlabel('Water Coating (mm)');    ylabel('Gi(1/km)')
0049 result=res;

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