Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS)

Resulting perturbation to atmospheric chemistry in the troposphere.

Composition and distribution of biomass burning outflow

O3 production and loss within the outflow

International partners: Dalhousie U., NASA, CNRS, Environment Canada, Free University of Amsterdam, Michigan Tech

• During ITOP, summer 2004, Canadian biomass burning plumes were intercepted in mid-Atlantic and Europe

• Biomass burning airmasses showed an unusual mixture of organic compounds within NOy (NO+NO2+PANs+HNO3+NO3+2N2O5+organic nitrates)

• Much NOy was held as PAN but its abundance was much higher than predicted by theory and very sensitive to temperature and altitude.

• It appears that NOy speciation holds the key to understanding O3 tendency (net P or L?) in biomass burning plumes

• No canonical O3:CO relationship

Motivation

BORTAS measurement campaign

• Based out of Halifax NS, Canada from 12 July to 3 August 2011.

• FAAM BAe146 aircraft

• 500 nautical mile range, approx. ceiling at 30000 ft

• 15 flights (including science transit flights between UK and Canada via Azores, ~20 hours)

• Support from ground-based, in situ, and satellite observations.

• Aerosol numbers distributions, composition (AMS, SP2)• VOCs, alcohols, ketones, aldehydes, ethers (WAS)• NOy speciation (LIF)• HCN, HNO3, formic acid (CIMS)• O3 (UV-abs)• CH3CN/oxygenates (PTR-MS)• CO2, CH4, CO• j(NO2), j(O1D)• Semi-volatile VOCs

Support measurements for BORTAS

Raman LidarSun photometerPARIS-IR FTIRPM2.5 NephelometerAMSWind profilerDA8 FTIR Ozone profiling Lidar

Intensive sounding network:Links to Env. Canada, AEROCAN/AERONET (Sun photometer), CORALNet (Lidar) and Toronto Atmospheric Observatory (FTIR)

Daily ozonesonde launches:•Bratt’s Lake SKChurchill MBEgbert ONGoose Bay NLSable Island NSStony Plain ABYarmouth NS

Mt. Pico observatory, Azores:Ground-based measurement site in central Atlantic at 2200 m elevation.NRT measurements of ozone, CO, NOx, NOy, NMHCs, BC.

Satellite observations:IASI – NRT CO columns and profilesACE-FTS•TES special observations for North America/North Atlantic.

Dalhousie Ground Station:

Observed biomass burning outflow: BORTAS flight B624

• Fifth research flight of the campaign, 21 July 2011.

• Science plan to sample biomass burning plume in mid-lower troposphere over Island of Newfoundland and Gulf of St. Lawrence.

• Flight plan superimposed over GEOS-5 CO forecast at 750 hPa.

• Aircraft altitude and measured CO correlate with location of outflow predicted by GEOS-5.

Flight plan for 21 July 2011GEOS-5 CO from boreal biomass burning sources at 750 hPa

Aircraft altitude Aircraft CO measurements

[m] [ppbv]

Aircraft altitude

Alt

itude /

km

Time / day of year

CO and acetonitrile

CO

/ p

pbv;

CH

3C

N /

pptv

Time / day of year

Observed vertical profiles of biomass burning outflow over Halifax

• GEOS-5 predicted boreal biomass burning outflow (forecast initialised on 20 July, midnight UTC) in mid to lower troposphere over Halifax starting just before midnight 21 July.

• Event coincided with BORTAS flight B623, which measured spiral profiles over Halifax, on 20 July.

• Layers of enhanced aerosol backscatter observed during aircraft spiral over Halifax and by Dalhousie lidar coincident to timing and altitude of predicted outflow.

• Two distinct layers observed at 2 km and 5km altitude correlate with enhanced CO and CH3CN.

20 July, 12z 21 July, 00z 21 July, 12z

Appro

x.

alt

itude /

km

GEOS-5 CO from boreal biomass burning, 20110720_00z

Dalhousie lidar

[ppbv]

CO / ppbv; CH3CN / pptv Green backscatter coefficient / ×10-4

Alt

itude /

km

Alt

itude /

km

Ascending spiral aircraft profile over Halifax~0100 UTC, 21 July 2011

Ozone distribution observed during BORTASO

3 /

ppbv

CO / ppbv

O3 / ppbv

Frequency

• Observed ozone distribution shows peak concentrations at 25 ppbv (measurements below 3 km) and 50 ppbv (background in free troposophere).

• Ozone mixing ratios have range of approx. 20 ppbv at highest CO values.

• Higher ozone values at lower CO values indicate mixing of other sources? Stratospheric influence?

• No discernible difference between ozone in background and plume air masses.

Parrington et al., in preparation

Hydrocarbon ratios as indicators of photochemical processing of air masses

Parrish et al. (2007)

ln(propane/ethane)ln

(n-b

uta

ne/e

thane)

ICARTT

ITCT 2K2

Parrish et al. (1992)

• Nonmethane hydrocarbon ratios tell us something about tropospheric oxidation and transport processes.

• Widely reported in the literature from aircraft and surface measurements [e.g. Parrish et al. (1992, 2007), Honrath et al. (2008), Jobson et al. (1994)].

• NMHC ratios (n-butane/ethane vs. propane/ethane) measured during BORTAS are consistent with reported values from previous campaigns.

• Slope of linear fit to all BORTAS data = 1.50 in the range 1.20 - 2.26 for individual research flights.

Photochemical age of plume measurements

• Photochemical ages calculated from ln(propane):ln(ethane) ratio and assuming mean OH mixing ratio of 2×106 molecules/cm3.

• CO (VOC and LIF) measurements show similar ‘age spectra’ with largest peak at 2-3 days and secondary peak at 6-7 days.

• Ozone measurements show no obvious relationship with photochemical age.

• Estimate ozone production (or loss) from ratio of ozone enhancement over background, ΔO3, to ΔCO and ΔNOy.

In plume

Out of plume

Parrington et al., in preparation

Evidence of ozone production in biomass burning outflow

0.005-0.731 (n = 21)

0.15 (0.07) ± 0.19

0.02-1.30 (n = 133)

0.21 (0.13) ± 0.22

0.004-1.437 (n = 53)

0.52 (0.44) ± 0.30

Range of ΔO3/ΔCO(# plume

measurements)

Mean (median)ΔO3/ΔCO

BORTAS

Jaffe and Wigder (2012)

• ΔO3/ΔCO measured during BORTAS aircraft campaign are consistent with observed ratios from previous measurement campaigns.

• Mean BORTAS values at higher end of reported means but median values in much better agreement possibly reflects large variability when considering all BORTAS research flights.

• At ages ≥5 days, mean and median BORTAS ratio more comparable to reported values for Siberian - indicates different emission source? NWT vs. NW Ontario? Need to verify source/age with back trajectories.

• This does not tell us anything about plume ozone chemistry.

Source and sink of O3 (slide from Piero Di Carlo)

, Italy

CETEMPSDepartment of PhysicsUniversity of L’Aquila, Italy

∑PNs

∑ANsRO2 + NO → RO + NO2

RO’ + O2 → R’O + HO2

HO2 + NO → OH + NO2

2NO2+ hν + O2 → 2 O3

RO2 + NO → RONO2

∑ANs is a good indicator of the photochemistry because O3 and ∑ANs have the same source

∑ANs

• High values of ∑AN and low values of Ox indicate suppressed ozone production (~6 molecules of ozone per molecule of ∑AN)

• Low ∑AN and high Ox indicate higher photochemical ozone production (>500 molecules of ozone per molecule of ∑AN).

• Similar distribution for Ox vs. NOz indicating relationship between number of ozone molecules produced per molecule of NOx that is oxidized.

• Plotting ratio of Ox/NOz indicates “ozone forming potential” of measured air masses.

Towards understanding plume ozone chemistryO

x (

O3+

NO

2)

/ ppbv

∑AN / ppbvParrington et al., in preparation

◇ nighttime, low aerosol◆ daytime, low aerosol◇ nighttime, high aerosol◆ daytime, high aerosol

Ox (

O3+

NO

2)

/ ppbv

NOz (NOy-NOx) / ppbv

Towards understanding plume ozone chemistry

Ox/N

Oz

NOx / ppbv Parrington et al., in preparation

◇ nighttime, low aerosol◆ daytime, low aerosol◇ nighttime, high aerosol◆ daytime, high aerosol

VOC-limitedNOx-limitedO

zone f

orm

ing p

ote

nti

al

• The relationship between O3/NOz and NOx tells us something about the chemical regime within the measured plumes.

• At high NOx, the plumes are in a VOC-limited regime with low OPE (i.e. freshly emitted plumes?).

• At low NOx, the plumes are in a NOx-limited regime with higher OPE (i.e. aged plumes).

BORTAS campaign summary

• Plume enhancements of organic species show strong linear relationship relative to CO.

• No clear relationship for ozone.

• Hydrocarbon ratios are consistent with values reported in literature for previous measurement campaigns.

• Photochemical ages of observed biomass burning plumes calculated from propane:ethane ratio range from 0 to 10 days with peak CO, VOC, and NOy measurements at 2-3 days of ageing.

• Evidence of ozone production in biomass burning outflow:

• Ratios of ΔO3/ΔCO in the plume measurements show strong correlation (r > 0.7) to photochemical age in the free troposphere (2-8 km).

• Relationship between ozone and ∑AN/NOz indicates influence of NOy partitioning.

• Enhanced potential for ozone formation in aged plume air masses with low aerosol loading.

• Consistent picture seen in data from other measurement campaigns over the same region (ABLE 3B, ARCTAS), not shown.

Dalhousie University•Tom Duck•Jim Drummond•Jeff Pierce•Randall Martin•Mark Gibson•Matt Seaboyer•Jonathan Franklin•Jason Hopper•Kimiko Sakamoto•Kaja Rotermund•Loren Bailey

Environment Canada•Lisa Langley•David Tarasick•Jane Liu•Steve Beauchamp•Richard Leaitch•Chris Fogarty•David Waugh•Doug Steeves•Lucy Chisholm

University of Toronto•Kaley Walker•Kim Strong•Cyndi Whaley•Debora Griffin

Naval Research Laboratory•Mike Fromm•Edward Hyer

University of Sherbrooke•Norm O’Neill

B.J. Stocks Wildfire Investigations Ltd.•Brian Stocks

University of Edinburgh•Paul Palmer•Mark Parrington•Stephan Matthiesen•Rob Trigwell•Eddy Barratt

University of York•Ally Lewis•James Lee•Andrew Rickard•Sarah Moller•Steve Andrews•Peter Bernath•Keith Tereszchuk

University of Leeds•Jenny Young

Acknowledgements: BORTAS contributors

NASA GMAO•Steven Pawson

University of ManchesterUniversity of East Anglia

L’aquila University

Extra slides

Overview of summer 2010 boreal fire activity

• Observed fire hotspots for season up to 31 August show large concentration in northern SK, extending into NWT.

• Fires also concentrated in QC (earlier in fire season) and BC.

• Aggregated MODIS fire counts for boreal North America (top) and Eurasia (bottom), for 1 July to 31 August.

• Fire counts do not exceed 10,000 but generally greater than 100 in northern SK, BC, and eastern Siberia.

Canadian fire activity: summer 2010 vs. 10 year average

http://www.ciffc.ca/

• Burnt area through BORTAS-A considerably higher than 10 year average.

• Number of fires slightly less apart from 3 week period between 17 July and 7 August.

• Slightly higher number of fires SK and QC but almost 10-fold increase in burnt area in SK.

http://fire.cfs.nrcan.gc.ca/firereport/report-rapport-eng.php

Data assimilation in BORTASGEOS-Chem capabilities

1) Identify and characterize biomass burning source regions (via emission inventories, e.g. GFED, FLAMBE, FINNv1)

2) Help identify and estimate pyroconvection(?)

3) Analyse characteristic ratios of chemical tracers (flaming vs smouldering emissions) as they evolve from the point of emission to where we can measure them with the BAe146 and beyond

4) Test consistency with ground-based and airborne measurements

5) Evaluate model chemistry and physical processes

Satellite measurements are integral to BORTAS

(Links to NCEO activities)

They will be (mainly) used to:

Data assimilation plans for BORTAS

• 4D-Var assimilation of BORTAS aircraft measurements

• use GEOS-Chem adjoint to evaluate model plume chemistry and evolution over the North Atlantic Ocean

• Assimilation of satellite data (TES and MetOp products)

• constrain model tracer distributions to isolate and evaluate uncertainties associated with emissions

• consistent comparison of aircraft and satellite products

TES observing modes for BORTAS

Global survey daytime observation locations, July 2008 Step and stare daytime observation locations, July 2008

• Global survey observations:

• standard operating mode, observations spaced ~2° (180 km) along orbit track.

• Special observations:

• Step and stare: observations spaced ~0.4° (45 km) along orbit track over latitude range of 50°.

• Stare: 32 observations taken over a single location on the closest orbit track (i.e. Halifax, NS).

• Potential for retrieving species related to biomass burning (e.g. methanol, ammonia, formic acid, HCN, PAN)

GEOS-Chem adjoint

• Plots show sensitivity of ozone in the free troposphere over Maritime Canada to NOx emission sources during July 2011.

• Sensitivity to biomass burning emissions distinct from lightning and anthropogenic emissions.

• Satellite data assimilation to evaluate model initial conditions and inputs (emissions sources).

• Assimilate aircraft measurements to evaluate impact on downwind chemistry of biomass burning outflow.

• Scale up aircraft measurements to compare against satellite observations.

Biomass Burning Lightning

Anthropogenic Aircraft/biofuel/soil

Optimizing biomass burning emissions

• Global 4D-Var inversion of GEOS-Chem CO model using MOPITT version 4 CO columns.

• Scaling factors show that CO emissions from all sources are too high across the northern hemisphere (too low in extra-tropical southern hemisphere).

MOPITT CO columns, 31 July 2010 Raw GEOS-Chem CO columns

Analysed GEOS-Chem CO columns Scaling factors for CO emissions, July 2010

[molec/cm2]

Parrington et al., ACP, 2012

Constraining the tropospheric ozone distribution

x̂ka =xk

f + K k[yobs −Hkxk

f ]

Sequential Sub-optimal Kalman filter

Kk =PkfHk

T(HkPkfHk

T + Rk)−1

Pka =(I -K kHk)Pk

f

Kalman Gain Matrix:

Analysis Error Cov. Matrix:

• Observation operator (H) accounts for TES averaging kernels and a priori profiles

• Analysis error variance transported as a passive tracer

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

O3 bias relative to ozonesondes

% difference

Pre

ssur

e / h

Pa

Parrington, et al., JGR, 2008

No TES assim.

TES assim.

• Satellite data assimilation to evaluate model initial conditions and inputs (emissions sources).

• Assimilate aircraft measurements to evaluate impact on downwind chemistry of biomass burning outflow.

• Scale up aircraft measurements to compare against satellite observations.

Atmospheric chemistry modelling