Find the intersection point between 2 curves
1 次查看(过去 30 天)
显示 更早的评论
Hi there!
I'm a new matlab user so I don't know all its features.
I'm having trouble in finding the intersection point between two curves (I_moon and Moon_ref). Can you help me?
This is my code:
%------------------------------------------------------------------------%
%------------------------------------------------------------------------%
%-----------------Average radiance emitted and reflected-----------------%
%------------------------------------------------------------------------%
%------------------------------------------------------------------------%
%Target: Moon;
%Atmosphere and surface: no atmosphere;
%Surface temperature: 130 K;
%Albedo: 0.136;
%Wavelength range: 0-50 μm;
%Data from: nasa.gov
clear all;
close all;
clear global;
clc
%--------------------------------Costants--------------------------------%
c=2.998*10^8; % speed of light in vacuum
h=6.6261*10.^-34; % Planck constant
k=1.38*10.^-23; % Boltzmann constant
sigma=5.67*(10^-8); %Stephen-Boltzmann constant
L=(0.0:0.01:50); %wavelength (μm)
T=130; %Moon average temperature (K)
albedo=0.136; %Moon albedo (ad)
d=1; %Sun-Moon distance (AU)
R=1737.1; %Moon average radius (km)
r=4.66e-3; %Sun radius (AU)
T_sun=5777; %Sun average temperature (K)
Fs=1366; %Solar constant at 1 AU (W/m^2)
%----------------------------Radiance emitted----------------------------%
I_sun=3.742./((L.^5).*(exp(1.439e4./(L.*5777))-1));
I_moon=3.742./((L.^5).*(exp(1.439e4./(L.*130))-1));
%---------------------------Radiance reflected---------------------------%
Moon_ref=albedo*((r^2)/(1^2))*I_sun;
%------------------------------Absorptance-------------------------------%
F=Fs*(1./(d.^2)); %Solar constants for Moon=1366 (W/(m^2))
Rad_intercepted=F.*pi.*((R.*(10^3)).^2); %Solar radiation intercepted by Moon=1.295 (W)
Rad_absorbed=F.*(1-albedo).*pi.*((R.*(10^3)).^2); %Radiation absorbed: Moon=1.1188e+16 (W)
Abs=Rad_absorbed./Rad_intercepted; %Absorptance values for: Moon=0.864
%---------------------------Total radiance-------------------------------%
ToT_moon=Moon_ref+(Abs*I_moon);
figure4 = figure;
axes1 = axes('Parent',figure4);
hold(axes1,'on');
ylabel({'Radiance'});
xlabel({'wavelength (μm)'});
title({'Moon','(130K)'});
xlim(axes1,[1 20]);
ylim(axes1,[1e-30 1]);
set(axes1,'YMinorTick','on','YScale','log');
plot(L,I_moon,'Color',[0 0 1]);
hold on
plot(L,Moon_ref,'Color',[1 0 0]);
plot(L,ToT_moon,'Color',[0 0 0]);
hold off;
legend({'Emitted','Reflected','Total'},'Location','southeast');
0 个评论
回答(1 个)
Stephan
2019-5-6
create a function handle depending from wave length, that subtracts both from each other. this is the objective function for using fzero function. As result you get the interception wave length.
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Weather and Atmospheric Science 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!