The Story of the Water :: Water Vapor

Water evaporation is the close to important gaseous reference point of infrargond opacity in the atmosphere, itaccounts for more or less 60% of the natural babys room effect for the clear skies 1, and provides thelargest positive feedback in model projections of mood throw 2. Therefore, piddle vaporvariability is an important issue in the word of global climate change 3 and in particularthe variability of stratospheric wet vapor has important radiative and chemical consequencesthat impact the global surface climate change 4.An increase of roughly 1% per year in stratospheric piddle vapor content has been observedduring the make it half of the 20th light speed 5, 6, with a more convincingly documented increaseduring the 1980s and most of the nineties than earlier. However, an updated bowel movement analysis 7of water vapor in the cast down mid-latitude stratosphere from Boulder balloon measurements andfrom HALOE (Halogen Occultation Experiment) 8 spaceborne observation s provides tr send awayestimates for the period 1980-2000 that are up to 40% lower than previously reported.Methane oxidation is a major lineage of water in stratosphere, and has been increasing overthe industrial period, however, the observed trend in stratospheric water vapor during the lasthalf of the 20th speed of light is too large to be attributed to methane oxidation alone 5, 9.The temperatures near the tropical tropopause should control the stratospheric water vaporcontent according to the equilibrium thermodynamics, importation more water vapor into thestratosphere when temperatures are warmer. However, tropical tropopause temperatures sirecooled meagrely over the period of the stratospheric water vapor increase 10, 11. Other mechanismshave been proposed to explain the increase of the stratospheric water vapor occurred inthe second half of 20th century, but so far the driving causes of this increase are unknown.The upward trend of stratospheric water vapor decreased in the last half of the 1990s witha near-zero trend between 1996 and 2000 12, 13. Furthermore, at the end of 2000 there wasa dramatic drop of about 10% of stratospheric water vapor 13. The trend analysis reportedin 14 extends until spring 2008 and it shows that a minimum was approximately reachedbetween 2004 and 2006 and an increase is observed afterwards.The drop in stratospheric water vapor that occurred at the end of 2000 is thought to haveslowed the swan of increase in global surface temperature over 2000-2009 by about 25% comparedto that which would have occurred due only to carbon dioxide and other nurserygases 4. On the other hand the increase in stratospheric water vapor occurred between 1980and 2000 would have enhanced the decadal rate of surface warming during the 1990s by about