UP IN THE AIR*: Connecting plants, particles and pollution

Colette L. HealdColorado State University

MITMarch 11, 2011

* Title taken from George Clooney & Paramount Photo taken from space shuttle Discovery

here!

ATMOSPHERIC COMPOSITION IS LINKED TO MAJOR ENVIRONMENTAL ISSUES

AIR QUALITY / HEALTH FERTILIZATIONCLIMATE

… AND DRIVEN BY THE BIOSPHERE

NEED TO UNDERSTAND ATMOSPHERIC COMPOSITION BETTER NOW AND THEN PREDICT THE FUTURE…

Problem: Observations are sparse over much of the globe

SATELLITESAIRCRAFT CAMPAIGNSSURFACE SITES

GLOBAL MODELS

Goal: Investigate global budgets, atmospheric sources and transformations

Past 2011 Future?

DISTURBANCE:Fires, beetles,

land use change

EMISSIONS:ParticlesOrganics

Inorganics…

+ oxidants

+ oxidation

O3

ANTHROPOGENIC INFLUENCE

↓ OH = ↑ CH4 lifetime

+ FEEDBACKS FROM CLIMATE CHANGE

(moisture, precipitation, T, hv)

?

ECONOMICS, POPULATION, ENERGY USE

DUST FROM NORTH AFRICA: IMPACTING AQ AND THE BIOSPHERE DOWN-WIND

More than half of dust emitted globally from N. Africa

TOMS: June 13-21, 2001

summer

winter/spring

Miami (1989-1997)

[Prospero et al., 1999]

[Prospero et al., 1981]

French Guiana (1978-1979)

DUST TRANSPORT FROM NORTH AFRICA

Global Model: GEOS-Chem(2x2.5)David Ridley (CSU)

CALIOP MODEL CALIOP MODEL

WINTER SUMMER

Annual Mean AOD

DEPOSITION OF AFRICAN DUST IN THE AMAZON

We estimate 13 Tg/yr transported to Amazon annually. This is ~25% of the P supply [Mahowald et al., 2005] for the Amazon. Otherwise from fires and biogenic particles?

Impact of greening of the Sahel on productivity of the Amazon?

[Ridley et al., in prep]

MAR-MAY

ISOPRENE: CONTROLLING AIR QUALITY AND CLIMATE

C5 H8: Reactive hydrocarbon emitted from plants (primarily broadleaf trees)

Annual global emissions ~ equivalent to methane emissions

+ OH

O3

Depletes OH(?) = ↑ CH4 lifetime

IPCC, 2007

CLIMATE

E=f( )

AIR QUALITY

ISOPRENE IN THE FUTURE

Isoprene emissions projected to increase substantially due to warmer climate and increasing vegetation density.

LARGE impact on oxidant chemistry and climate

2000 2100

NPP ↑ Temperature↑

Surface O3 ↑ 10-30 ppb [Sanderson et al., 2003]

Methane lifetime increases[Shindell et al., 2007] SOA burden ↑ > 20%

[Heald et al., 2008]

(US 8-hr standard = 75 ppb)

CO2 INHIBITION COMPENSATES FOR PREDICTED TEMPERATURE-DRIVEN INCREASE IN ISOPRENE EMISSION

CONCLUSION: Isoprene emission predicted to remain ~constantImportant implications for oxidative environment of the troposphere…

* With fixed vegetation

508 523

696

479Eis

op

(TgC

yr-1)

2000 2100 (A1B)

Standard model (MEGAN)Standard model + CO2 inhibition

Global Model: NCAR CAM3-CLM3 (2x2.5)

Empirical parameterization from plant studies

[Wilkinson et al., 2009]

UNLESS…CO2 FERTILIZATION IS STRONG

CLM DGVM projects a 3x increase in LAI associated with NPP and a northward expansion of vegetation.

[Alo and Wang, 2008]

Isoprene emissions more than double! (1242 TgCyr-1)

If include N limitation:Only ~25% of the growth in NPP [Thornton et al., 2007;

Bonan and Levis, 2010]

[Heald et al., 2009]

Future land use may be the greatest uncertainty in chemistry-climate predictions

+ oxidants

Terpenes(gas-phase)

Hydrocarbons(gas-phase & particulate)

ORGANIC AEROSOL: THE MESSIEST AEROSOLS!

Primary Organic Aerosol: emittedSecondary Organic Aerosol: formed

NATURAL ANTHROPOGENIC

These sources estimated ~ 50 TgC/yr

ORGANIC AEROSOL MAKES UP AN IMPORTANT/DOMINANT FRACTION OF OBSERVED AEROSOL

Globally makes up 25-75% of total fine aerosol at the surface (ignoring dust here)

[Zhang et al., 2007]SulfateOrganics

MODELS UNDERESTIMATE OBSERVED ORGANIC AEROSOL

Model underestimate observed OA concentrations by factor of 2-10 in the mean.Big Issue in the community: What is the source of “missing OA”.

[Heald et al. in prep]Global Model: GEOS-Chem(2x2.5)

2001-2009

2-10!OA Mass(fine)

PRIMARY BIOLOGICAL AEROSOL PARTICLES (PBAP)

POLLEN

BACTERIA VIRUSES

FUNGUS

ALGAEPLANTDEBRIS

Jaenicke [2005] suggests may be large (1000s Tg/yr)Elbert et al. [2007] suggest emission of fungal spores ~ 25 TgC/yr

PBAP estimates ~1000 Tg/yr would swamp all other sources of organic aerosol. KEY QUESTION: what is the size (lifetime) of these particles??

FIRST SIMULATION OF FUNGAL SPORE PBAP

25% emitted in fine mode , makes up 7% of total fine mode OA source(~4 TgC/yr)

I. Mannitol is a unique tracer for fungal spores [Bauer et al., 2008; Elbert et al., 2007]: 1 pg mannitol = 38 pg OM

II. Optimize model emissions as a function of meteorological and phenological parameters (wind, T, humidity, radiation, surface wetness, precipitation, leaf area index, water vapour concentrations, boundary layer depths) to match global observations of mannitol in PM

Global Model: GEOS-Chem(2x2.5)

WHEN AND WHERE MIGHT FUNGAL SPORES BE IMPORTANT?

Pronounced seasonality in extratropics (corresponding to

vegetation cover), peaking in late-summer/fall as in measurements.

Fungal spores make a modest but regionally important contribution to organic carbon aerosol budget.

More observations needed to test…

Not the missing source of OA[Heald and Spracklen, 2009]

Simulated Seasonality Contribution of PBAP to surface OA (fine)

MARINE PBAP

Ocean

Surfactant Layer (with Organics)

WINDSea-spray emission

[O’Dowd et al., 2004]

Under biologically active conditions, OA has been observed to dominate sub-micron aerosol mass.

SeaWIFSSPRING (high biological activity)

IS THE OCEAN AN IMPORTANT SOURCE OF PBAP?Previous estimates range from 2.3 to 75 TgC/yr

No marine OA With marine OA

Observations from 5 ship cruises show that marine OA from 2 schemes (based on MODIS /

SeaWIFS chlorphyll-a) of ~8 TgC/yr are more than sufficient to reproduce sub-micron OA.

Not a large source of aerosol.

Kateryna Lapina –submitted to ACPD

OA Emissions

Global Model: GEOS-Chem(2x2.5)

CAN SATELLITE OBSERVATIONS SHED ANY LIGHT ON THE BUDGET OF OA?

SURFACE REFLECTANCE

Bottom-up calculations suggest that SOA source may be anywhere from 140-910 TgC/yr [Goldstein and Galbally, 2007].

topz

0

AOD= α RH z M z dz

Organicaerosol

Sulfate Dust

Sea SaltNitrate

SATELLITE AOD

Assumptions:Optical PropertiesSize Distributions

Aerosol Distributions

AEROSOL SPECIATED MASS CONCENTRATIONS

Soot

ATTRIBUTE ENTIRE MODEL UNDERESTIMATE OF AOD TO ORGANICS

Estimate that ~150 TgC/yr source is required to close the

MISR-GEOS-Chem* discrepancy.

DJF JJA

MISR

GEOS-Chem*

MISR-GEOS-Chem*

*excluding OA

This is more than THREE TIMES what is currently included in global models….

BUT at the low end of Goldstein & Gallbally [2007] range.

Missing source likely SOA.

HAVE WE REDUCED THE UNCERTAINTY ON THE OA BUDGET?

910

47 Existing GEOS-Chem sources

140 Our satellite top-down estimate 150

Range estimated

by: Goldstein

and Galbally [2007]

All units in TgCyr-1

[Heald et al., 2010]

ATMOSPHERIC AMMONIA: A FUTURE CONTROL ON PM?

Biomass burningAnimalsAgriculture

…stretching the definition of “natural” to include agriculture

…but NH3 is tough to measure

(acidic)SO4

2-SO2

HNO3NH3

(NH4)2

SO4

IF NH3 left-overNH4

NO3

NH3 emissions major source of fixed N

NEW GLOBAL MEASUREMENTS OF AMMONIA FROM SPACE

IASI (DOFS > 0.05)GEOS-Chem

(with IASI operator) IASI – GEOS-Chem

Summer 2009 NH3 Columns

Large model underestimate in Southern California!Emissions? Thermodynamic processing? Bi-directional flux?

High values observed at Bakersfield during CalNex 2010

Jennifer Murphy (U. Toronto)

60 ppb

*preliminary IASI obs (ULB)

EMISSIONS:ParticlesOrganics

NOx…

+ oxidants

+ oxidation

O3

ANTHROPOGENIC INFLUENCE

ISOPRENEDUST

OA (PBAP)

MARINE PBAP

Emphasized here: investigating emissions from the biosphere (their importance for AQ, climate & productivity)

Also critical: the role of these (and other) emissions in changing the chemical environment of the atmosphere

The “natural” atmosphere is poorly understood, variable, and a key baseline against which to assess anthropogenic

influence.

AMMONIA

ACKNOWLEDGEMENTSDavid A. Ridley, Kateryna Lapina, Sonia Kreidenweis (CSU)Dominick Spracklen, Steve Arnold (Leeds University)Easan Drury (NREL)Russ Monson and Mick Wilkinson (UC Boulder)Alex Guenther (NCAR)

Data: Hugh Coe, Gordon McFiggans, James Allan & Matthew Jolleys (U Manchester), Jose Jimenez (UC Boulder), Rodney Weber (G Tech), Ann Middlebrook & Tim Bates (NOAA), Lynn Russell & Lelia Hawkins (Scripps), Soeren Zorn (Harvard), Cathy Clerbaux and Lieven Clarisse (ULB), Jen Murphy (U of T)

Satellite Data:

Funding: