Gothamist might have to bring in Sarah Fresh as a regular photo queen. This time she sends in this snapshot (click to enlarge) of someone's science homework on a sidewalk on Lorimer St. chalked with the water cycle. Remember back to your elementary school science class and you'll recall the water cycle is the basic progression of evaporation (and transpiration which is the process of process of evaporation through plant leaves.. we like to think they are sweating), condensation, precipitation, and collection (which includes surface runoff and infiltration into the ground). Gothamist is trying very hard not to imagine the dirty, moist-garbage soaked summer streets in Chinatown in this "runoff" cycle.

Some interesting things about the cycle...

  • only about 10% of water evaporated from the ocean travels far enough to fall as precipitation over land, the rest falls back into the ocean.
  • 2/3 of the vapor in the air comes from evaporation from lakes and other land-based bodies of water and transpiration.
  • Only 1/3 of precipitation that falls over land runs off into lakes, streams, and is returned to the oceans. The rest is re-evaporated or transpired to fall as precipitation again. Kind of like re-rain.

Ultimately this whole system balances out, which is a good thing. Over longer periods of time if precipitation that falls does not end up back in the oceans or in the atmosphere, it could be transplanted as polar ice and the ocean levels would then fall and we might be considered to be in an "ice age." The reverse would occur if the polar ice caps melt, and the ocean levels would rise. These things would take a very long time (contrary to recent Hollywood suggestions), but do play a significant role in our planet's atmospheric well being. That is why there is plenty of research being done on the cycle including $311 million worth conducted by the U.S. Global Change Research Program, as well as efforts by the Climate Change Research Initiative (CCRI), NOAA, and others. Thanks guys!