CONTINENTAL OUTFLOW AND INTERCONTINENTAL TRANSPORT AT NORTHERN MIDLATITUDES and a few UTLS topics

1
CONTINENTAL OUTFLOW AND INTERCONTINENTAL
TRANSPORT AT NORTHERN MIDLATITUDES (and a few
UT/LS topics)

• Daniel J. Jacob
• Atmospheric Chemistry Modeling Group
• Harvard University

2
ARE ATMOSPHERIC OBSERVATIONS OF
ACETONECONSISTENT WITH CURRENT UNDERSTANDINGOF
SOURCES AND SINKS?
ABLE -3B
Surface sites
PEM -WB
SONEX
PEM-TB
3
GLOBAL BUDGET OF ATMOSPHERIC ACETONE

• 
  Singh et al. Jacob et al. 2002
• 
  2000 (a priori) (a
  posteriori)
• SOURCES (Tg yr-1) 56 (37-80)
  78 (49-105) 95 (80-110)
• Terrestrial vegetation 15 (10-20)
  26 (0-52) 33 (24-42)
• Plant decay 6 (4-8)
  9 (0-18) 2 (-3-7)
• Biomass burning 5 (3-10)
  3 (2-5) 5 (3-7)
• Industry 2
  (1-3) 1 (1-2) 1
  (1-2)
• Oceans 0
  10 (0-20) 27 (21-33)
• Oxidation of isoalkanes 17 (12-24)
  20 (10-30) 21 (16-26)
• Oxidation of terpenes, MBO 11 (7-15)
  9 (3-15) 7 (3-11)
• SINKS (Tg yr-1) 56 (37-80)
  78 95
• Photolysis 36
  (24-51) 44 46
• Oxidation by OH 13 (9-19)
  25 27
• Deposition to land 7 (4-10)
  9 9
• Uptake by ocean 0
  0 14
• LIFETIME 16 days
  20 days 15 days

4
OCEANIC SIGNATURE IN ATMOSPHERIC ACETONE
OBSERVATIONS
South Pacific Singh et al., 2001
southern Norway Solberg et al., 1996
Low winter values over Europe imply ocean sink
High values over South Pacific imply large ocean
source
a priori sources/sinks c2 1.3 a posteriori
sources/sinks (including microbial ocean
sink, photochemical ocean source) c2 0.39
5
SURFACE AIR ACETONE CONCENTRATIONSIN A
POSTERIORI SIMULATION
6
METHYL IODIDE TRACER OF MARINE CONVECTION IN
GLOBAL ATMOSPHERIC MODELSLoss by photolysis (4
days), relatively uniform ocean source, large
aircraft data base D.R. Blake, UCI
Observations Model (GEOS-CHEM)
MCI 0.40 (obs) 0.22 (mod)
MCI 0.16 (obs) 0.14 (mod)

• Define Marine Convection Index (MCI) as ratio of
  upper tropospheric (8-12 km)
• to lower tropospheric (0-2.5 km) CH3I
  concentrations
• MCI over Pacific ranges from 0.11 (Easter Island
  dry season) to 0.40 (observations over tropical
  Pacific
• GEOS-CHEM reproduces observed MCI with little
  global bias (11) but poor correlation (r2
  0.15, n11)

Simple model for ocean source
Bell et al. 2002
7
SURFACE OZONE BACKGROUND IN THE U.S. IMPORTED
FROM OUTSIDE IS A SIZABLE INCREMENT TOWARDS
VIOLATION OF U.S. AIR QUALITY STANDARDS(even
more so in Europe!)
Europe (8-h avg.)
Europe (seasonal)
U.S. (8-h avg.)
U.S. (1-h avg.)
0 20 40
60 80 100
120 ppbv
preindustrial
present background
8
OZONE BACKGROUND OVER U.S. IS GENERALLY DEPLETED
DURING REGIONAL POLLUTION EPISODESdue to
deposition and chemical loss under stagnant
conditions
Observed (J.W. Munger) model (GEOS-CHEM) model
background
O3 vs. (NOy-NOx) At Harvard Forest,
Massachusetts
Background (clean conditions)
Background (pollution episodes)
Fiore et al. 2002
Pollution coordinate
9
RANGE OF ASIAN/EUROPEAN POLLUTION SURFACE OZONE
ENHANCEMENTS OVER THE U.S. IN SUMMERas
determined from a simulation with these emissions
shut off
Subsidence of Asian pollution local production
Max Asian/European pollution enhancements (up to
14 ppbv) occur at intermediate ozone levels
(50-70 ppbv)
stagnation
tropical air
MAJOR CONCERN IF U.S. OZONE STANDARD WERE TO
DECREASE!
U.S. standard
European standards
Fiore et al. 2002
10
NORTH AMERICAN OZONE OUTFLOW IN SURFACE AIR
(GEOS-CHEM model results for 1997)
APRIL
L
H
L
JULY
H
Li et al. 2002
11
OZONE DATA AT MACE HEAD, IRELAND
Model vs. observed stats, 1993-1997
Time series, Mar-Aug 1997
GEOS-CHEM model
N.America pollution events in model
Li et al. 2002
12
FORECASTING TRANSATLANTIC TRANSPORT OF NORTH
AMERICAN POLLUTION TO EUROPE WITH THENORTH
ATLANTIC OSCILLATION (NAO) INDEX
NAO index normalized surface P anomaly between
Iceland and Azores
NAO Index
North American ozone pollution enhancement At
Mace Head, Ireland (GEOS-CHEM model)
r 0.57
Li et al. 2002
Greenhouse warming a NAO index shift a change
in transatlantic

transport of pollution
13
EFFECT OF NORTH AMERICAN SOURCESON VIOLATIONS OF
EUROPEAN AIR QUALITY STANDARD (55 ppbv, 8-h
average)
GEOS-CHEM model results, summer 1997
Number of violation days (out of 92)
of violation days that would not have been in
absence of N.American emissions
Li et al. 2002
14
Enhancements in Asian surface ozone due to
European anthropogenic emissions (GEOS-CHEM, 1996)
Liu et al. 2002
15
GLOBAL MODEL ANALYSIS OF OZONESONDE OBSERVATIONS
ALONG THE PACIFIC RIM (1993-1997)
Hong Kong, 1996
High UT variability at Hong Kong in winter-spring
reflects alternance of tropical and stratospheric
influences
300-120 hPa
observations GEOS-CHEM model
700-300 hPa
Spring enhancement from SE Asian biomass burning
850-700 hPa
Liu et al. 2002
16
ALTERNANCE OF TROPICAL AND STRATOSPHERIC
INFLUENCES IN WINTER UT OVER HONG
KONGcomparison of Dec 24, 1996 and Jan 6, 1997
Observed GEOS-CHEM
Sonde and model profiles
Model ozone concentrations and fluxes, 200 hPa
Stratospheric ozone tracer at longitude of Hong
Kong
Liu et al. 2002
17
200 hPa ozone fluxes across Pacific Rim
(GEOS-CHEM, 1996)

• Tropical and midlatitude influences
• Easterly circulation away from Pacific in summer

Liu et al. 2002
18
SUMMER UT OZONE POLLUTION EVENT OVER HONG
KONGAugust 21, 1996
Asian pollution
Sonde and model profiles
Observed GEOS-CHEM
Model enhancement of ozone concentrations and
fluxes due to Asian anthropogenic sources
Liu et al. 2002
19
WHAT OBSERVATIONS AND MODELS ARE NEEDEDTO BETTER
QUANTIFY INTERCONTINENTAL TRANSPORT?
SATELLITE OBSERVATIONS Global and continuous but
few species, low resolution
Source/sink inventories
3-D CHEMICAL TRACER MODELS
SURFACE OBSERVATIONS high resolution but
spatially limited
Assimilated meteorological data
AIRCRAFT OBSERVATIONS High resolution, targeted
flights provide critical snapshots for model
testing
Chemical and aerosol processes
INTERCONTINENTAL TRANSPORT CONCENTRATIONS AND
FLUXES
20
TRACE-P MISSION(Mar-Apr 2001)
Satellite data in near-real time MOPITT TOMS SEAW
IFS AVHRR LIS
Stratospheric intrusions
FLIGHT PLANNING
Long-range transport from Europe, N. America,
Africa
3D chemical model forecasts - ECHAM -
GEOS-CHEM - Iowa/Kyushu - Meso-NH -LaRC/U.
Wisconsin
ASIAN OUTFLOW
Boundary layer chemical/aerosol processing
DC-8
P-3
PACIFIC

• Emissions
• Fossil fuel
• Biomass burning
• Biosphere, dust

ASIA
PACIFIC
21
GOME daily data of NO2 and HCHO tropospheric
columns during TRACE-P (3/15 - )
Randall Martin
Thomas Kurosu/Kelly Chance
Slant HCHO column, single orbit on 3/27
Mean slant NO2 column, 3/16-4/15
22
CARBON MONOXIDE CONCENTRATIONSMEASURED IN TRACE-P
23
C2Cl4 CONCENTRATIONS MEASURED IN TRACE-P
Symbol size -1/altitude
Don Blake, UCI
24
INVERSE ANALYSIS OF CO SET UP FOR TRACE-Pa
priori Asian emissions appear low but not
outrageously so
Paul Palmer, Harvard
25
PRELIMINARY GLOBAL (GEOS-CHEM) 3-D MODEL ANALYSIS
OF TRACE-P OBSERVATIONS
Mat Evans, Harvard
26
GLOBAL MODEL ANALYSIS OF TRACE-P OBSERVATIONS
SENSITIVITY TO SOURCES
OZONE
CO
Median model/observed
Median model/observed
Median model/observed
Mat Evans, Harvard
27
INTERCONTINENTAL TRANSPORT EXPERIMENT NORTH
AMERICA (INTEX-NA)
The next NASA Global Tropospheric Experiment
(GTE) mission
OBJECTIVES

• To quantify the North American import and export
  of
• (1) atmospheric oxidants and their precursors,
  (2) aerosols and their precursors, (3) long-lived
  greenhouse gases
• To relate this import/export to surface
  sources/sinks and to continental boundary layer
  chemistry

TWO AIRCRAFT NASA DC-8 and P-3

• TWO PHASES
• Summer 2004
• active photochemistry, biosphere
• aerosol radiative forcing
• carbon uptake
• Spring 2006
• maximum Asian inflow
• contrast with summer

28
INTEX NOMINAL FLIGHT TRACKS FOR PHASE A (SUMMER)
RL
BG
WL
AZ
DR
BR
NO
HI
DC-8
P-3B
Ozonesonde sites
29
INTEX-NA HAS LINKAGES WITH A NUMBER OF
ATMOSPHERIC PROGRAMS

• In situ
• North American Carbon Program (2002-)
• NOAA Northeast U.S. Study (2004)
• European UT/LS program (-2005) - LETS TALK!!!
• Asian APARE program (ongoing)
• Satellites
• Terra MOPITT (1999-)
• Envisat SCIAMACHY, MIPAS (2002-)
• NMP/GIFTS (2004-)
• Aura TES, OMI, HRDLS, TES (2004-)
• Modeling
• EPA OAQPS/ORD climate change/air quality
  initiative (2001-2010)