Estimating earth surface temperature from variation in sun spot density

sun_earth.m

% Refs:
% 1. https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law#cite_note-Solar_constant_at_ground_level-9
% 2. https://en.wikipedia.org/wiki/Sunspot

% Kelvin
K = 273.15;

% sun earch distance
r = 149600000; % meters

% temperature at sun surface
T0 = 5780; % Kelvin

R0 = 695700; % meters

T = @(sf) T0 * sf * sqrt(R0 / (2*r)) - K ; % degrees
Y = arrayfun(T, linspace(0.9, 1.05));
plot(Y);