# Gnuplot script to show solar spectral irradiance at 1 AU, # in W/(m2.micrometer). # The Planck spectrum of a "blacbody Sun" giving the same total irradiance # is shown too. # Three solar spectra are: # above-atmosphere, tilted AM 1.5 total, and direct AM 1.5 # taken from # http://rredc.nrel.gov/solar/spectra/am1.5/ # Titles are in Czech. Script by Jan Hollan, 2013 set encoding iso_8859_2 set term pdf color enhanced font "Arial-Medium" #set term postscript eps color enhanced set out "solar_czm.pdf" #set size 0.7 set grid Planck(x,t) = \ 1E-6*3.741E-16/(( exp(5*log((x*1E-6))) )*(exp(1.439E-2/(x*t*1E-6))-1)) aur = (149.6/0.6963)**2 set title font ",7" \ "Sluneční spektra, log. stupnice {/Symbol l}; \ Planckova funkce pro 5778 K" set ylabel \ "({/Symbol l} / {/Symbol m}m) × \ hustota spektrálního zářivého toku\n \ / (W.m^{/*0.7 -2}{/Symbol m}m^{/*0.7 -1})" set xlabel "ln ({/Symbol l} / {/Symbol m}m)" set xtics 1 nomirror set x2label "{/Symbol l} / nm" set x2tics font ",4" \ ("Ca\n 395 " log(.395), \ "H{/Symbol g}\n 434" log(.434),\ "H{/Symbol b}\n 486" log(.486), \ "Na\n 589" log(.589), \ "H{/Symbol a}\n 656" log(.65628), \ "O_2\n 759" log(.759), \ "1000" log(1), "2000" log(2) , "4000" log(4)) # "b\n 517" log(517), \ # "Fe,527" log(527), \ f(x)=exp(x)*Planck(exp(x),5778) / aur plot [-1.4:1.4] \ "a.txt" using (log($1/1000)):($2*$1) \ with lines lt 1 title 'nad ovzduším',\ "a.txt" using (log($1/1000)):($3*$1) with lines lt 2 \ title 'AM 1,5 vč. rozptýleného záření' ,\ "a.txt" using (log($1/1000)):($4*$1) with lines lt 3 \ title 'skrze AM 1,5', \ f(x) title 'černé těleso 5778 K' with lines lt 5 lw 2 quit