Asian Summer Monsoon Anticyclone – What is …：亚洲夏季季风反气旋–什么是…….ppt

1,Overview of the Asian monsoon anticyclone and influence on the UTLS,Bill Randel Atmospheric Chemistry Division NCAR Earth System Laboratory,Thanks to: Mijeong Park, Laura Pan, Louisa Emmons, Doug Kinnison, MLS team, ACE team,What is the monsoon anticyclone, and why is it interesting?,dominant circulation feature of NH summer UTLS forced by deep convection over India and Bay of Bengal associated with local maxima in trace constituents (water vapor, ozone, pollutants) active region for stratosphere- troposphere coupling,deep convection,monsoon circulation near 16 km,monsoon circulation near 16 km,carbon monoxide near 16 km MLS satellite data,Seasonal cycle of lower stratosphere H2O,summer monsoon maximum,L,H,Antarctic dehydration,HALOE instrument on UARS satellite 1992-2005,summertime lower stratosphere maxima linked to Asia and North American monsoons,Rosenlof et al 1997 Jackson et al 1998 Dethof et al 1999,Likely contribution to water vapor entering stratosphere: Bannister et al, 2004; Gettelman et al, 2004; Park et al, 2004; Fu et al, 2006,Climatological precipitation in NH summer,6,monsoon,Dynamical Background,Dynamical Background,anticyclone upper troposphere,cyclone lower troposphere,Cyclone at the surface, anticyclone in the upper troposphere,7,atmosphere response to steady tropical heating (Gill, 1980),longitude,imposed heating,latitude,symmetric Rossby gyres west of heating,Kelvin wave east of heating,Highwood and Hoskins (1998),Upper troposphere,Lower troposphere,anticyclones,cyclones,conv,div,idealized vertical structure,9,Convection, heating,Anticyclones in the UT,anticyclones,Convection (heating),Gill-type Solution,10,observations,Note that the anticyclone does not lie on top of the deep convection,geopotential height and winds 100 hPa,Lower troposphere,Upper troposphere,H,L,cold,warm,Randel and Park, JGR, 2006,Dynamical Background,Anticyclonic circulation extends into lower stratosphere,11,tropopause,warm troposphere,cold lower stratosphere,Cold, high tropopause linked to frequent cirrus,frequent cirrus near tropopause,Cloud fraction near 16 km,13,Potential vorticity at 360 K (12 km),AIRS water vapor at 360 K,Anticyclone is region of low PV,July 10, 2003,High H2O confined inside anticyclone,Confinement within the anticyclone: idealized transport experiments,initialize 2400 particles inside anticyclone advect with observed winds for 20 days test different pressure levels,Idealized transport simulation at 150 hPa,day 0,day 10,day 20,large fraction remain inside anticyclone,Confinement within region of strongest winds,17,Earth,Jupiter,Persistent anticyclone (Great Red Spot),18,Transport linked to the anticyclone: Chemical structure observed by satellites Transport pathways diagnosed from MOZART chemical transport model (Mijeong Park) Coupling with the stratosphere,MLS observations of CO,Global coverage 1 day 4 km layer centered near 16 km,enhanced CO mixing ratio in anticyclone,MLS CO (Jun/2/2005) 100 hPa,19,MLS climatology,MLS CO (Jul-Aug) 100 hPa,MLS O3 (Jul-Aug) 100 hPa,anticyclone high CO,low ozone,20,Synoptic variability,MLS CO (100 hPa),100 hPa CO linked to monsoon convection,21,Park et al, JGR, 2007,Transport pathways,CO surface emission (India and South China),convective transport (main outflow near 200 hPa),confinement by anticyclone (transport to stratosphere?),22,Transport above 200 hPa by large-scale circulation (+overshooting convection?),Diagnosed from chemical transport model Park et al, JGR, 2009,23,MLS H2O,24,HDO enrichment from deep convection,Water vapor isotopologue HDO from ACE-FTS data,MLS H2O,Note differences between Asian and N. American monsoon,25,Anticyclonic circulation contributes to large-scale transport to/from tropics Kanopka et al, ACP, 2010,MLS observations,CLaMS simulation,Also: Dunkerton, 1995 Chen, 1995 isentropic summer strat-trop exchange linked to anticyclone,Hydrogen cyanide (HCN),DJF,JJA,tropical minimum: air with recent ocean contact,HCN source: biomass burning,HCN lifetime: 4 years in free atmosphere, but sink from contact with ocean,Observations from ACE-FTS satellite,Transport to the stratosphere via the monsoon anticyclone,27,ACE JJA climatology,tropical minimum,transport to stratosphere via monsoon,Randel et al, Science, 2010,28,Complementary perspectives of CO vs. HCN,CO lifetime 2 months,HCN lifetime 4 years,tropical minimum,no tropical minimum,Key points: Asian monsoon circulation provides effective vertical transport and chemical confinement in UTLS anticyclone (region of chronic pollution) CTM with climatological sources and large-scale meteorology shows reasonable agreement with satellite observations Observations of HCN suggest monsoon transport to stratosphere - especially effective for Asian pollution (SO2, NOx, other),Key points: Asian monsoon circulation provides effective vertical transport and chemical confinement in UTLS anticyclone (region of chronic pollution) CTM with climatological sources and large-scale meteorology shows reasonable agreement with satellite observations Observations of HCN suggest monsoon transport to stratosphere - especially effective for Asian pollution (SO2, NOx, other),Hofmann et al. 2009 propose increases due to Chinese SO2 increases,stratospheric aerosol,Outstanding issues: Very few aircraft/balloon measurements in anticyclone (so far) How important is convective overshooting vs. large-scale transport? How does the diurnal cycle influence convective transport? What is the detailed behavior of convective and cirrus clouds? Are aerosols observed? If so, what optical properties? (absorbing?) What is the radiation balance near the tropopause? What is the detailed structure across vortex edge? (e.g. filamentation?) What are important exchange mechanisms across edge? What active chemistry is occurring? Do aerosols nucleate and grow? What controls interannual variability? How will anticyclone evolve in a changing climate?,32,12 noon,3 pm,6 pm,Tibet plateau convection in late afternoon,CALIPSO, Cloudsat observations at 1:30,convective cloud statistics from 3-hour geostationary (CLAUS) data,Blue = deep, hig