i want to modeling this example as a code in matlab and give me a figure please

Example $8$: Direct Beam Radiation at the Surface of the Earth

Find the direct beam solar radiation normal to the sun's rays at solar noon on a clear day for latitude $33\mathrm{.}7$ on May $21.$

Solution:

May $21$ is day number $141.$

The apparent extraterrestrial flux $A$ is:

$A=1160+75sin[\frac{360}{365}(n-275)]=1160+75sin[\frac{360}{365}(141-275)]$

$=1104\frac{W}{m^2}$

The optical depth is

$k=0\mathrm{.}174+0\mathrm{.}035sin[\frac{360}{365}(n-100)]$

$=0\mathrm{.}174+0\mathrm{.}035sin[\frac{360}{365}(141-100)]=0\mathrm{.}197$

On May $21$ solar declination is $20\mathrm{.}1,$ so the altitude angle of the sun at solar noon is

${}_N=90-L+=90-33\mathrm{.}7+20\mathrm{.}1=76\mathrm{.}4$

The air mass ratio is:

$m=\frac{1}{sin}=\frac{1}{sin(76\mathrm{.}4)}=1\mathrm{.}029$

The predicted value of clear sky beam radiation at the earth's surface is:

$I_B=A{e}^{-km}=1104e^{-0\mathrm{.}1971\mathrm{.}029}=902\frac{W}{m^2}$