BRIDGING THE SCALES IN ATMOSPHERIC CHEMISTRY LOCAL TO
BRIDGING THE SCALES IN ATMOSPHERIC CHEMISTRY: LOCAL TO GLOBAL Daniel J. Jacob with Jenny A. Fisher, Monika Kopacz, Lin Zhang, Tzung-May Fu, Easan E. Drury, Eric M. Leibensperger, Shiliang Wu, Loretta J. Mickley, Chris D. Holmes and support from NASA, EPRI, NSF, EPA
SCALES OF ATMOSPHERIC CHEMISTRY PROBLEMS Disasters Visibility Ozone layer Annecy Urban smog Regional smog Climate Point source Acid rain Biogeochemical cycles LOCAL < 100 km REGIONAL 100 -1000 km GLOBAL > 1000 km
SCALE SEPARATION AND INTERACTIONS GLOBAL planetary waves, general circulation… Deep convection tchemio>n 10 d ut l o v e l o subsidence s s ro n e o a i t i d l& n a o c i c m y r e a h c REGIONALound r LOCAL a e fronts, ive b -lin n o ct N a BL turbulence, r monsoons… e t n i / c i sea breezes… am tchem ~ 0. 1 -10 d n y D tchem < 1 d mesoscale LAND synoptic scale OCEANS
NASA/ARCTAS AIRCRAFT CAMPAIGN (April+July 2008) Objective: better understand changes in Arctic pollution and climate Focus on mid-latitudes pollution, Arctic haze (spring), boreal forest fires (summer) Calipso Aqua A- tra Aura E ur o p e pl Fi N. A Fi m re e Yellowknife pl s Fairbanks u Cold m Lake e s Arctic climate forcing Air quality u m A si a re er ic a Mid-latitudes in Deposition Arctic
INTEGRATING SATELLITE, AIRCRAFT, AND MODEL INFORMATION TO BETTER UNDERSTAND SOURCES OF ARCTIC POLLUTION Asian plume transported to Arctic in warm conveyor belt on April 16, 2008 Aircraft CO data at 4 -6 km (500 h. Pa) compared to GEOS-Chem chemical transport model Satellites provide global continuous observations; Aircraft provide satellite validation, complementary species, local process information; Models provide link between aircraft and satellite, platform for understanding and prediction AIRS satellite data for CO at 500 h. Pa compared to GEOS-Chem with averaging kernels J. A. Fisher [Harvard], G. Diskin [La. RC], J. Warner [UMBC] Aircraft AIRS GEOS-Chem
SATELLITES AND MODELS ARE INSEPARABLE …must be viewed with in situ data as a unified observing system Radiative transfer model & its inverse Chemical transport model & its inverse aircraft evaluation a priori info relationships to processes Surface sites Formaldehyde absorption lines 336 -356 nm backscattered radiance spectrum measured from space Formaldehyde column Concentrations (OMI, JJA 2006) Isoprene emission fluxes Millet et al. [JGR 2008]
INTEGRATING SATELLITE, AIRCRAFT, AND GROUND-BASED AEROSOL DATA TO CONSTRAIN U. S. AEROSOL SOURCES DURING ICARTT (Jul-Aug ’ 04) MODIS AODs at 0. 47 mm MODIS c 5 operational. product. MODIS Synthetic top-of-atmosphere (TOA) reflectance TOA reflectance Optimize retrieval of aerosol optical depth (AOD) and surface concentrations backscattered radiation GEOS-Chem AODs Difference between MODIS and GEOS-Chem AODs; Size distribution constraint on aerosol sources GEOS-Chem Observed chemical Aircraft: Model transport Aerosol chemistry Sulfate model Size distribution AERONET in circles OC Optical properties dust prior info 0. 1 1 mm surface networks: IMPROVE (aerosol chemistry), AERONET (AOD) Drury et al. (in prep. )
INTEX-B AIRCRAFT CAMPAIGN OVER NORTHEAST PACIFIC (2006) AIRS and TES satellite observations of transpacific plume TES GEOS-Chem CO columns AIRS A aircraft B track TES observes ozone as well as CO; observed ozone-correlation indicates ozone production over Pacific but signal is noisy (observations are sparse) Zhang et al. [ACP, in press]
TRANSPACIFIC PLUME OBSERVED BY INTEX-B AIRCRAFT (May 9, 2006) Backward (7 d) and forward (3 d) trajectories for points A and B A-north branch Solid: observations Dash: GEOS-Chem A PAN B O 3 CO graveyard of Asian pollution B-south branch • Ozone is produced in the southern branch following subsidence and decomposition of PAN to NOx • Most of this ozone circles around the Pacific High and eventually dies during transport to western equatorial Pacific; only a small fraction reaches the western U. S. O 3 CO PAN NO HNO 3 Zhang et al. [ACP, in press]
CONSEQUENCES FOR U. S. SURFACE OZONE U. S. surface ozone during INTEX-B campaign (April-May 2006) Observations (Dan Jaffe, UW) and GEOS-Chem at Mt. Batchelor, Oregon (2, 700 m) Mean Asian surface pollution enhancement (GEOS-Chem) Observed: 54 ± 10 GEOS-Chem: 53 ± 8 GEOS-Chem Asian pollution: 9 ± 2 Apr 17 Apr 23 Apr 29 May 5 May 11 ppb 2000 -2006 doubling of Asian NOx emissions has increased U. S. surface ozone by 1 -3 ppbv in the West Zhang et al. , ACP, in press
INTERCONTINENTAL SOURCE ATTRIBUTION OF OZONE USING MODEL ADJOINTS GEOS-Chem adjoint simulation for INTEX- B period (Apr-May 2006) 6% 6% 23% 21% 17% Contribution of ozone production regions to ozone concentration at Mt. Batchelor Observatory Mean East Asian pollution enhancement of 9. 2 ppb at MBO includes 5. 6 ppb from China and 3. 6 ppb from Japan+Korea Zhang et al. [in prep. ]
ORIGIN OF HIGH ORGANIC AEROSOL CONCENTRATIONS IN FREE TROPOSPHERE? ACE-Asia aircraft data over Japan (April-May 2001) Observed (Huebert) GEOS-Chem model Observed (Russell) Observations show 1 -3 mg m-3 background; model including standard scheme for secondary organic aerosol (SOA) is too low by factor 10 -100 Heald et al. [GRL 2005]
ICARTT AIRCRAFT DATA OVER EASTERN U. S. (Jul-Aug 2004) Mean vertical profile of water-soluble organic carbon (WSOC) aerosol Correlation with other variables measured from aircraft (grey = obs, colors = model) Observed (Weber) Model w/ standard SOA Model w/ dicarbonyl SOA added includes SOA from irreversible cloud uptake of glyoxal & methylglyoxal Fu et al. [AE, submitted]
SENSITIVITY OF SURFACE AIR QUALITY TO METEOROLOGICAL VARIABLES Insights into the effect of climate change on air quality Effect of climate change Ozone PM (aerosol) Stagnation Temperature ? ? Mixing depth Precipitation = = Cloud cover Humidity = (relative) Jacob and Winner, AE 2008
IMPORTANCE OF MID-LATITUDES CYCLONES IN AIR POLLUTION METEOROLOGY Cold fronts from mid-latitude cyclones are the principal ventilation process for U. S. Midwest/Northeast, western Europe, China Clean air sweeps behind cold front IPCC shows decrease + N shift of cyclones from 21 st-century climate change; already seen in 1950 -2000 climatological data
CORRELATIONS AND TRENDS OF POLLUTION EPISODES AND CYCLONES IN NORTHEAST U. S. # pollution episode days (O 3>80 ppb) and # cyclones tracking across SE Canada in summer 1980 -2006 observations k ne c tra clo y C # cyclones # episodes • Strong correlation; cyclone frequency is predictor of pollution episode frequency • 1980 -2006 decrease in cyclone frequency would imply a corresponding degradation of air quality if emissions had remained constant • Expected # of 80 ppb exceedance days in Northeast dropped from 30 in 1980 to 10 in 2006, but would have dropped to zero by 2001 in absence of cyclone trend! Leibensperger et al. [ACP, submittted]
ENSEMBLE MODEL ANALYSIS OF CLIMATE CHANGE EFFECT ON OZONE AIR QUALITY IN THE U. S. Results from six coupled GCM-CTM simulations 2000 -2050 change of 8 -h daily max ozone in summer, ppb keeping anthropogenic emissions constant Weaver et al. [BAMS, submitted] Northeast Midwest California Texas Southeast • Models show consistent projection of ozone increase in Northeast/Midwest - likely reflects decrease in mid-latitude cyclone frequency • …but large disagreements in Southeast - due in part to isoprene chemistry ? ? NOx How will isoprene emissions actually respond to climate change? Increase in CO 2, land cover change… isoprene nitrates
REGIONAL CLIMATE SENSITIVITY TO ANTHROPOGENIC AEROSOLS Sulfur emission controls will enhance warming – but by how much? 15 -year GISS GCM simulation with zeroed U. S. aerosols vs. control present-day simulation Large warming over eastern U. S. (>1 o C), cooling in Arctic; teleconnection over East Asia Mickley et al. [in prep. ] Aerosol optical depths, at 550 nm D DJF surface temperatures
GLOBAL BIOGEOCHEMICAL CYCLING OF MERCURY 5600 Atmospheric component of cycle: ? ? ? Hg(0) OH, O 3, Br aq, hn Hg(II) wet dry 1, 150, 000 deposition PRESENT-DAY Inventories in Mg Flows in Mg a-1 Selin et al. [GBC 2008] 7000
DIURNAL CYCLE OF REACTIVE GASEOUS MERCURY (RGM) IN MARINE BOUNDARY LAYER Early a. m. rise, midday peak suggests Br chemistry, deposition via sea salt uptake Subtropical Pacific cruise data MBL budgets Observed [Laurier et al. , 2003] Model Hg(0)+Br Model Hg(0)+OH Model predicts that ~80% of Hg(II) in MBL should be in sea salt: Hg(0) Br, OH Br Hg. Br T Holmes et al. [in prep. ] sea-salt aerosol Hg. Br. X Hg. Cl 32 -, Hg. Cl 42 - deposition
OBSERVING SYSTEM FOR ATMOSPHERIC COMPOSITION IN 2025 SATELLITES: LEO, Geo, L 1 orbits, lunar Global/regional continuous mapping Top-down constraints on emissions Stratospheric monitoring Sun-Earth interactions ADAPTIVE EARTH SYSTEM MODELS Data assimilation, inversion Understanding & prediction SURFACE SITES, SHIPS Long-term trends Surface fluxes Process information ROBOTIC AIRCRAFT Process information Surface fluxes
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