﻿EFFECTS 
  OF 
  SOLAR 
  RADIATION 
  — 
  O'BRIEN 
  

  

  121 
  

  

  for 
  the 
  Temperate 
  Zones. 
  The 
  results 
  are 
  shown 
  in 
  figures 
  12 
  and 
  13 
  

   for 
  clear 
  days 
  at 
  noon 
  as 
  a 
  function 
  of 
  time 
  of 
  year. 
  The 
  scale 
  of 
  

   months 
  is 
  for 
  north 
  latitudes, 
  but 
  exactly 
  similar 
  curves 
  will 
  apply 
  

   to 
  south 
  latitudes 
  except 
  that 
  the 
  scale 
  for 
  time 
  of 
  year 
  must 
  be 
  

   shifted 
  by 
  6 
  months 
  from 
  the 
  indicated 
  values. 
  In 
  order 
  to 
  show 
  the 
  

   effects 
  of 
  hour 
  of 
  the 
  day 
  at 
  the 
  three 
  selected 
  latitudes 
  and 
  for 
  the 
  

  

  3000 
  

   WAVELENGTH 
  IN 
  ANGSTROMS 
  

  

  Figure 
  8. 
  — 
  Solar 
  spectral 
  energy 
  for 
  various 
  air 
  masses. 
  (2.8 
  mm. 
  ozone 
  in 
  zenith 
  

  

  atmosphere. 
  ) 
  

  

  two 
  selected 
  quantities 
  of 
  ozone, 
  it 
  is 
  necessary 
  to 
  plot 
  six 
  families 
  

   of 
  curves. 
  These 
  are 
  shown 
  in 
  figures 
  14 
  to 
  19, 
  inclusive. 
  It 
  will 
  be 
  

   noted 
  that 
  near 
  midsummer 
  the 
  spread 
  in 
  latitude 
  between 
  33° 
  and 
  

   43° 
  results 
  in 
  only 
  a 
  slight 
  drop 
  in 
  the 
  effectiveness 
  of 
  sunlight 
  near 
  

   noon, 
  providing 
  that 
  the 
  ozone 
  is 
  constant. 
  In 
  midwinter 
  the 
  effective 
  

   change 
  of 
  latitude 
  is 
  far 
  more 
  important, 
  the 
  10° 
  difference 
  between 
  

   33° 
  and 
  43° 
  resulting 
  in 
  a 
  change 
  in 
  effectiveness 
  of 
  sunlight 
  of 
  more 
  

   than 
  fourfold. 
  

  

  