Air mass (solar energy)
Solar intensity
Table:
Solar intensity vs. zenith angle

z

{\displaystyle z}

and airmass coefficient AM

z

{\displaystyle z}

AM

range due to pollution[12]

formula (I.1)

ASTM G-173[11]

degree

W/m2

W/m2

W/m2

-

0

1367[15]

1353

1347.9[16]

0°

1

840 .. 1130 = 990 ± 15%

1040

23°

1.09

800 .. 1110 = 960 ± 16%[17]

1020

30°

1.15

780 .. 1100 = 940 ± 17%

1010

45°

1.41

710 .. 1060 = 880 ± 20%[17]

950

48.2°

1.5

680 .. 1050 = 870 ± 21%[17]

930

1000.4[18]

60°

2

560 .. 970 = 770 ± 27%

840

70°

2.9

430 .. 880 = 650 ± 34%[17]

710

75°

3.8

330 .. 800 = 560 ± 41%[17]

620

80°

5.6

200 .. 660 = 430 ± 53%

470

85°

10

85 .. 480 = 280 ± 70%

270

90°

38

20

Looking at the data table for 'Air mass (solar energy)' titled 'Solar intensity', create one factual sentence about the highlighted cells, without adding extra data and format it within the following JSON object {"answer": "YOUR ANSWER"}.