solar day vs sunshine

solar day

noun
  • one day of solar time, the time between successive noons; the time in which a planet such as Earth apparently rotates once around its axis, relative to the sun (on Earth about 24 hours as an average - the length of solar day is not constant throughout the year) 

sunshine

noun
  • A location on which the sun's rays fall. 

  • Geniality or cheerfulness. 

  • Used to address someone who has just woken up and/or is very sleepy. 

  • The effect which the sun has when it lights and warms some place. 

  • The direct rays, light or warmth of the sun. 

  • Friendly form of address often reserved for juniors. 

  • Ironic form of address used to an inferior or troublemaker. 

  • A source of cheerfulness or joy. 

adj
  • Open to and permitting public access, especially with regard to activities that were previously closed-door or back-room meetings. 

How often have the words solar day and sunshine occurred in a corpus of books? (source: Google Ngram Viewer )