The Story of the Water :: Water Vapor

Water dehydrationisation is the some heavy gaseous source of infr ared opacity in the atmosphere, itaccounts for about(predicate) 60% of the natural greenhouse effect for the clear skies 1, and provides thelargest positive feedback in model projections of climate change 2. Therefore, water supply vaporvariability is an important issue in the discussion of global climate change 3 and in particularthe variability of stratospheric water vapor has important radiative and chemical consequencesthat affect the global come up climate change 4.An increment of roughly 1% per year in stratospheric water vapor bailiwick has been observedduring the give out half of the 20th century 5, 6, with a more convincingly put down step-upduring the 1980s and most of the 1990s than earlier. However, an updated skid analysis 7of water vapor in the lower mid-latitude stratosphere from Boulder balloon measurements andfrom HALOE (Halogen Occultation Experiment) 8 spaceborne observations provides disregardestimates for the period 1980-2000 that are up to 40% lower than previously account.Methane oxidation is a major source of water in stratosphere, and has been increasing everyplacethe industrial period, however, the observed tr destination in stratospheric water vapor during the pull roundhalf of the 20th century 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, importing more water vapor into thestratosphere when temperatures are warmer. However, tropical tropopause temperatures havecooled slightly 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 farther 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 dangle 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 graze of increase in global surface temperature over 2000-2009 by about 25% comparedto that which would have occurred due hardly to carbon dioxide and other greenhousegases 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