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SUMMARY:Designing a strategy for merging atmospheric chemistry models and 
 measurements: Going after what matters - Prof. Michael Prather\,  Earth sy
 stem Science Dept\, UC Irvine
DTSTART:20180604T150000Z
DTEND:20180604T160000Z
UID:TALK106729@talks.cam.ac.uk
CONTACT:Dr Alex Archibald
DESCRIPTION:Our traditional approach in combining measurements and models 
 has been to measure one or more chemical species (we try to pick the impor
 tant ones) and then comparing with model simulations.  Another approach is
  to assimilate observed species\, merging measurements and model chemistry
 -transport to produce a single\, fully fleshed record of a species that me
 rges the best and worst of its parents.  A common weakness of these approa
 ches is that they center on the static composition of the atmosphere rathe
 r than what is happening in the atmosphere to change composition\, i.e.\, 
 the chemical reactivity\, the rates of production and loss of ozone and me
 thane\, which are not directly measurable.  \n\nThe NASA Atmospheric Tomog
 raphy (ATom) Mission was designed to go after the reactivity of the tropos
 phere\, identifying "Which Air Matters?"  ATom completed its fourth and fi
 nal deployment in May 2018.  It has circumnavigated the global troposphere
  over 4 seasons.\nIt has characterized the chemistry and transport history
  of the remote troposphere\, through the Pacific and Atlantic Ocean basins
 \, over Antarctica and the Arctic. Using the 10-second averages (2.5 km) w
 ith constant profiling from 500 ft to 12 km\, ATom has collected chemical 
 specification for over 120\,000 air parcels\, with enough information to b
 e able to describe (with models) the subsequent 24-hour evolution of the p
 arcel in terms of ozone and methane.  This chemical climatology allows us 
 to evaluate chemistry-climate models and identifies the 'hot' parcels that
  are driving the evolution of the troposphere.  ATom also measured a clima
 tology of photolysis rates that allows us to test the role of clouds in dr
 iving photochemistry and reactivity.  This talk presents the strategy\, de
 sign and some early results from the ATom models and measurements. \n\nFor
  an introduction to the approach and methodologies see the two pre-ATom pa
 pers:\nAtmos. Chem. Phys.\, 17(14)\, 9081-9102\, doi: 10.5194/acp-17-9081-
 2017. "Global Atmospheric Chemistry – Which Air Matters"        \nAtmos.
  Meas. Tech.\, 11\, 2653–2668\, 2018\, doi: 10.5194/amt-11-2653-2018. "H
 ow well can global chemistry models calculate the reactivity of short-live
 d greenhouse gases in the remote troposphere\, knowing the chemical compos
 ition\,"\n
LOCATION:Pfizer Lecture Theatre\, Department of Chemistry
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