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Fire & Smoke in the Earth System: Evaluating the impact of fire aerosols on regional and global climate. Michael G. Tosca University of California, Irvine Presented to: NASA JPL || 1 March 2012.

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slide1

Fire & Smoke in the Earth System:Evaluating the impact of fire aerosols on regional and global climate

Michael G. Tosca

University of California, Irvine

Presented to: NASA JPL || 1 March 2012

slide2

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Human and climate drivers of climate

Fire, humans and climate

CLIMATE

FIRE

HUMANS

slide3

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Human and climate drivers of climate

Fire, humans and climate

Westerling et al., 2006

slide4

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Human and climate drivers of climate

Fire, humans and climate

Swetnam et al., 1993

slide5

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Human and climate drivers of climate

Fire, humans and climate

Aldersley et al., 2011

slide6

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Human and climate drivers of climate

Fire, humans and climate

Aldersley et al., 2011

slide7

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Human and climate drivers of climate

Fire impact on the carbon cycle

van der Werf et al., 2004

Observed

Inversion model

Forward model

slide8

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Human and climate drivers of climate

Fire impact on the carbon cycle

van der Werf et al., 2004

Observed

Inversion model

Forward model

During 1997-98, fire emissions explained ~2/3 of the observed CO2 growth rate

slide9

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Smoke emissions and the direct, semi-direct & indirect aerosol effects

Fire aerosol emissions - an introduction

Total global fire emissions: 2-4 Pg C yr-11,2,3

Deforestation emissions: 0.6-0.7 Pg Cyr-11(8% of fossil fuel emissions)

Smoke emissions: 50-100 Tg yr-11,3,4

5-10% of smoke emission mass is black carbon 5

1van der Werf, et al., 2010 || 2Wiedinmyer et al., 2011 || 3Reid et al., 2009 || 4Bauer and Menon, 2012 || 5Reid et al., 2005

slide10

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Smoke emissions and the direct, semi-direct & indirect aerosol effects

Fire aerosol emissions - an introduction

Total global fire emissions: 2-4 Pg C yr-11,2,3

Deforestation emissions: 0.6-0.7 Pg Cyr-11(8% of fossil fuel emissions)

Smoke emissions: 50-100 Tg yr-11,3,4

5-10% of smoke emission mass is black carbon 5

Fires contribute ~30% of total particulate (smoke) and black carbon emissions worldwide. 6

6Lamarque et al., 2010

1van der Werf, et al., 2010 || 2Wiedinmyer et al., 2011 || 3Reid et al., 2009 || 4Bauer and Menon, 2012 || 5Reid et al., 2005

slide11

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Smoke emissions and the direct, semi-direct & indirect aerosol effects

Fire aerosol emissions - an introduction

Total global fire emissions: 2-4 Pg C yr-11,2,3

Deforestation emissions: 0.6-0.7 Pg Cyr-11 (8% of fossil fuel emissions)

Smoke emissions: 50-100 Tg yr-11,3,4

5-10% of smoke emission mass is black carbon 5

direct radiative effect:aerosols absorb and scatter SW radiation

Penner et al., 1994

slide12

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Smoke emissions and the direct, semi-direct & indirect aerosol effects

Fire aerosol emissions - an introduction

Total global fire emissions: 2-4 Pg C yr-11,2,3

Deforestation emissions: 0.6-0.7 Pg Cyr-11 (8% of fossil fuel emissions)

Smoke emissions: 50-100 Tg yr-11,3,4

5-10% of smoke emission mass is black carbon 5

semi-direct radiative effect:

Ackerman et al., 2000

slide13

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Smoke emissions and the direct, semi-direct & indirect aerosol effects

Fire aerosol emissions - an introduction

Total global fire emissions: 2-4 Pg C yr-11,2,3

Deforestation emissions: 0.6-0.7 Pg Cyr-11 (8% of fossil fuel emissions)

Smoke emissions: 50-100 Tg yr-11,3,4

5-10% of smoke emission mass is black carbon 5

semi-direct radiative effect:aerosol-induced tropospheric warming reduces cloud cover

Ackerman et al., 2000

slide14

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Smoke emissions and the direct, semi-direct & indirect aerosol effects

Fire aerosol emissions - an introduction

Total global fire emissions: 2-4 Pg C yr-11,2,3

Deforestation emissions: 0.6-0.7 Pg Cyr-11 (8% of fossil fuel emissions)

Smoke emissions: 50-100 Tg yr-11,3,4

5-10% of smoke emission mass is black carbon 5

first indirect effect:

Twomey, 1977

slide15

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Smoke emissions and the direct, semi-direct & indirect aerosol effects

Fire aerosol emissions - an introduction

Total global fire emissions: 2-4 Pg C yr-11,2,3

Deforestation emissions: 0.6-0.7 Pg Cyr-11 (8% of fossil fuel emissions)

Smoke emissions: 50-100 Tg yr-11,3,4

5-10% of smoke emission mass is black carbon 5

first indirect effect:aerosols decrease cloud droplet size, increase albedo

Twomey, 1977

slide16

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Smoke emissions and the direct, semi-direct & indirect aerosol effects

Fire aerosol emissions - an introduction

Total global fire emissions: 2-4 Pg C yr-11,2,3

Deforestation emissions: 0.6-0.7 Pg Cyr-11 (8% of fossil fuel emissions)

Smoke emissions: 50-100 Tg yr-11,3,4

5-10% of smoke emission mass is black carbon 5

second indirect effect:

Albrecht, 1989

slide17

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Smoke emissions and the direct, semi-direct & indirect aerosol effects

Fire aerosol emissions - an introduction

Total global fire emissions: 2-4 Pg C yr-11,2,3

Deforestation emissions: 0.6-0.7 Pg Cyr-11 (8% of fossil fuel emissions)

Smoke emissions: 50-100 Tg yr-11,3,4

5-10% of smoke emission mass is black carbon 5

second indirect effect:aerosols increase cloud lifetime, reduce precipitation (?)

Albrecht, 1989

slide18

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Radiative forcing from fire aerosols

Global fire forcing (aerosols)

-1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5

  • Global radiative forcing (RF) from all aerosols is –0.5 W m-2
  • RF from fire aerosols is +0.005 W m-2

from: Bauer et al., 2012

slide19

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Global fire patterns

Global distribution of fire emissions

from: van der Werf et al., 2010

slide20

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Global fire patterns

High burning regions

slide21

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Science goals and objectives

Hypotheses

Fires in tropical Asian peat forests generally smolder and are injected within the boundary layer.

Climate impacts of fire aerosols during El Niño drought provide evidence of a positive feedback.

Global climate is strongly influenced by the radiative and microphysical effects of fire aerosols; tropical forests near source regions are particularly vulnerable to climate changes.

slide22

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Burning in equatorial Asia (Indonesia, Malaysia, Papau New Guinea)

southeast + equatorial Asia

slide23

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Burning in equatorial Asia (Indonesia, Malaysia, Papau New Guinea)

Map of equatorial Asia

Borneo

Sumatra

slide24

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Burning in equatorial Asia (Indonesia, Malaysia, Papau New Guinea)

Link between ENSO and fire

El Niño

 °C

La Niña

slide25

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Burning in equatorial Asia (Indonesia, Malaysia, Papau New Guinea)

Link between ENSO and fire

El Niño

 °C

Tg month-1

La Niña

slide26

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Burning in equatorial Asia (Indonesia, Malaysia, Papau New Guinea)

Link between ENSO and fire

El Niño

 °C

Tg month-1

La Niña

slide27

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Burning in equatorial Asia (Indonesia, Malaysia, Papau New Guinea)

Link between ENSO and fire

El Niño

 °C

Tg month-1

La Niña

slide28

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Burning in equatorial Asia (Indonesia, Malaysia, Papau New Guinea)

Fire during El Niño driven by low precipitation

  • Exponential relationship; almost piecewise w/ critical value ~100 mm month-1
  • High burning in 1997 and 2006 associated with average dry season precipitation ~50 mm month-1
  • Very low burning in 1998, 1999, 2000 associated with average dry season precipitation >150 mm month-1

from: van der Werf et al., 2008

slide29

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Burning in equatorial Asia (Indonesia, Malaysia, Papau New Guinea)

Fire during El Niño driven by low precipitation

  • Fairly recent phenomenon, especially on Borneo, associated with changing migration/settlement patterns

Visibility records from airports record no significant smoke events prior to 1985 despite incidence of drought and El Niño.

from: Field et al., 2009

slide30

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Extreme fire events during El Niño

  • 10-year time series of fire in equatorial Asia from MODIS/MISR
  • Gray bars indicate El Niño events; 80% of fires during 2001-2009 during El Niño

from: Tosca et al., 2011

slide31

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work 5. Conclusions

  • El Niño–fire feedback loop

Proposed feedback loop

slide32

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work 5. Conclusions

  • El Niño–fire feedback loop

Proposed feedback loop

slide33

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Characterizing the vertical extent of smoke

INITIAL QUESTION: At what vertical level is smoke primarily injected?

from: Tosca et al., 2011

slide34

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Characterizing the vertical extent of smoke

INITIAL QUESTION: At what vertical level is smoke primarily injected?

WHY WE CARE: Spatially expansive regions of smoke have potentially large climate effects; how do we represent smoke plumes in a climate model?

from: Tosca et al., 2011

slide35

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Characterizing the vertical extent of smoke

1. Estimating smoke height using the MISR Interactive Explorer (MINX)

slide36

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Characterizing the vertical extent of smoke

1. Estimating smoke height using the MISR Interactive Explorer (MINX)

slide37

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Plume locations

2. Digitized 317 plumes on Borneo and Sumatra from 2001-2009

peat forest

“other” rainforest

from:Tosca et al., 2011

slide38

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Plume locations - insight on injection height?

2. Digitized 317 plumes on Borneo and Sumatra from 2001-2009

peat forest

“other” rainforest

  • 75% of plumes in “peat forests” - high soil carbon, high moisture content
    • How will this affect injection height?

from:Tosca et al., 2011

slide39

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Characterizing the vertical extent of smoke

  • 96% of all plumes injected into the Atmospheric Boundary Layer

from:Tosca et al., 2011

slide40

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Characterizing the vertical extent of smoke

  • 96% of all plumes injected into the Atmospheric Boundary Layer (ABL)
  • Plumes on Borneo higher during El Niño (dry years), possibly owing to high ABLs

La Niña

El Niño

Mean height (El Niño) = 724 ± 16 m

Mean height (La Niña) = 633 ± 23 m

from:Tosca et al., 2011

slide41

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Characterizing the vertical extent of smoke

  • 96% of all plumes injected into the Atmospheric Boundary Layer (ABL)
  • Plumes on Borneo higher during El Niño (dry years), possibly owing to high ABLs

from:Tosca et al., 2011

slide42

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Smoke plume evolution to smoke clouds

  • Over time, plumes evolve into “smoke clouds” — regionally expansive, persistent

from:Tosca et al., 2011

slide43

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Smoke plume evolution to smoke clouds

  • Over time, plumes evolve into “smoke clouds” — regionally expansive, persistent
  • “Smoke clouds” are higher, cover more area, more climatologically important.

from:Tosca et al., 2011

slide44

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

Smoke plume evolution to smoke clouds

  • Over time, plumes evolve into “smoke clouds” — regionally expansive, persistent
  • Results from CALIPSO confirm MISR observations.

from:Tosca et al., 2011

slide45

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Temporal, spatial and vertical characterization of fires and plumes

August-October average aerosol optical depth

“high fire”

“high fire – low fire”

MISR

(02, 04, 06) – (00, 01, 03, 05)

MODIS

CAM3

97 – 00

from: Tosca et al., 2010

slide46

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

August-October average aerosol optical depth

“high fire”

“high fire – low fire”

MISR

(02, 04, 06) – (00, 01, 03, 05)

How does climate respond to an aerosol forcing of this magnitude?

MODIS

CAM3

97 – 00

from: Tosca et al., 2010

slide47

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

Radiative forcing from 1997 fires

Podgorny et al., 2003

slide48

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

Method for simulating climate response

Force the Community Atmosphere Model (CAM3) w/ monthly-varying, annually repeating 1997 fire emissions from GFED, version 21

Force a second simulation with repeating 2000 fire emissions from GFEDv2.

Smoke injected into the boundary layer – consistent with injection height work.

Aerosols interacted with radiation directly but not cloud microphysics, therefore our simulations consider the direct and semi-direct effects

Each simulation was: 10 year spin-up (not included in averages) + 30 year annually-repeating.

“Anomalies” are the difference between HIGHFIRE and LOWFIRE.

1van der Werf et al., 2006

slide49

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

Seasonal mean climate forcing (HIGHFIRE – LOWFIRE)

  • Smoke (BC & OC) emissions peak from August through November over Indonesia
  • Aerosol optical depth also peaks during this time, with maximum area-averaged anomalies of 0.5-0.6 during September

from: Tosca et al., 2010

slide50

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

Seasonal mean climate forcing (HIGHFIRE – LOWFIRE)

  • Smoke (BC & OC) emissions peak from August through November over Indonesia
  • Aerosol optical depth also peaks during this time, with maximum area-averaged anomalies of 0.5-0.6 during September

from: Tosca et al., 2010

slide51

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

Seasonal mean climate response

  • Smoke (BC & OC) emissions peak from August through November over Indonesia
  • Aerosol optical depth also peaks during this time, with maximum area-averaged anomalies of 0.5-0.6 during September
  • Surface cooling, atmospheric warming, near-zero (slightly positive) TOA RF.
  • Ocean and land temperatures cooled significantly (–0.6ºC in October) — one month lag in response to forcing
  • Precipitation signficantly reduced (10%) during September and October
  • Evaporation also decreases = drought conditions develop.

from: Tosca et al., 2010

slide52

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

Seasonal mean climate response

  • Smoke (BC & OC) emissions peak from August through November over Indonesia
  • Aerosol optical depth also peaks during this time, with maximum area-averaged anomalies of 0.5-0.6 during September
  • Surface cooling, atmospheric warming, near-zero (slightly positive) TOA RF.
  • Ocean and land temperatures cooled significantly (–0.6ºC in October) — one month lag in response to forcing
  • Precipitation signficantly reduced (10%) during September and October
  • Evaporation also decreases = drought conditions develop.

from: Tosca et al., 2010

slide53

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

Mechanisms for precipitation response

Aug-Oct Temp (ºC)

  • Large area of reduced surface temperatures

from: Tosca et al., 2010

slide54

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

Mechanisms for precipitation response

Aug-Oct Temp (ºC)

  • Large area of reduced surface temperatures
  • Increased solar heating aloft

Sept

from: Tosca et al., 2010

slide55

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols in equatorial Asia

Mechanisms for precipitation response

Aug-Oct Temp (ºC)

  • Large area of reduced surface temperatures
  • Increased solar heating aloft
  • Increase subsidence at the surface, limit convection = reduce precipitation.

Sept

Aug-Oct Divergence (x10-6 s-1)

from: Tosca et al., 2010

slide56

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work 5. Conclusions

  • El Niño–fire feedback loop

Evidence for a feedback …

slide57

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • El Niño–fire feedback loop

Evidence for a feedback …

slide58

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • El Niño–fire feedback loop

Evidence for a feedback …

‘indirect effects’ — do they change the sign?

slide59

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Global response?

BIG QUESTION: WHAT IS THE GLOBAL CLIMATE IMPACT OF FIRE AEROSOLS?

from: Tosca et al., 2012

slide60

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Global response?

BIG QUESTION: WHAT IS THE GLOBAL CLIMATE IMPACT OF FIRE AEROSOLS?

Caveat: We want to accurately simulate the magnitude of the forcing – requires matching simulated optical depths to observations.

from: Tosca et al., 2012

slide61

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Method for simulating climate response

  • Force Community Atmosphere Model, version 5 (CAM5) with monthly varying emissions from 1997–2009.
  • Scale emissions in burning regions by optimizing simulated optical depths using MISR/MODIS satellite data
  • Experimental simulations:
    • 15-year spin-up; 4 cycles of monthly repeating emissions (1997-2009), 52 years total (FIRE)
    • 15-year spin-up; no smoke emissions, all other variables same as (A). (NOFIRE)
  • 4. Climate “response” to fire aerosols is interpreted as FIRE – NOFIRE. Simulations consider direct, semi-direct, & indirect effects

from: Tosca et al., 2012

slide62

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Scaling emissions

  • Choose regions where fire aerosols are dominant contributor to area-wide optical depth

from: Tosca et al., 2012

slide63

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Scaling emissions

  • Choose regions where fire aerosols are dominant contributor to area-wide optical depth
  • CAM5 massively underestimates optical depth from fires — remedy = scale emissions upward.

from: Tosca et al., 2012

slide64

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Scaling emissions

  • Choose regions where fire aerosols are dominant contributor to area-wide optical depth
  • CAM5 massively underestimates optical depth from fires — remedy = scale emissions upward.
  • Regression slopes between simulations with original emissions and observations were 0.3-0.4 — too low.

from: Tosca et al., 2012

slide65

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Scaling emissions

  • Choose regions where fire aerosols are dominant contributor to area-wide optical depth
  • CAM5 massively underestimates optical depth from fires — remedy = scale emissions upward.
  • Regression slopes between simulations with original emissions and observations were 0.3-0.4 — too low.
  • After scaling, simulated optical depths were better correlated with observations

from: Tosca et al., 2012

slide66

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Scaling emissions

  • Choose regions where fire aerosols are dominant contributor to area-wide optical depth
  • CAM5 massively underestimates optical depth from fires — remedy = scale emissions upward.
  • Regression slopes between simulations with original emissions and observations were 0.3-0.4 — too low.
  • After scaling, simulated optical depths were better correlated with observations

from: Tosca et al., 2012

slide67

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Annual climate response

from: Tosca et al., 2012

slide68

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Optical depth “forcing”

  • Globally, aerosol optical depth increased 13% (+0.02) due to fire aerosols

stippling is 95% confidence interval (student t-test)

from: Tosca et al., 2012

slide69

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Surface radiation response

  • All-sky net surface radiation decreased 1% (1.7 W m-2)

from: Tosca et al., 2012

slide70

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Surface temperature response

  • Surface temperature declined 0.3°C

from: Tosca et al., 2012

slide71

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Zonal climate response

  • Largest response near the equator
  • Optical depth peaked near 5°N during DJF and 5°S during JJA
  • Major reduction in precip near the equator during all seasons

from: Tosca et al., 2012

slide72

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Zonal climate response

  • Largest response near the equator
  • Optical depth peaked near 5°N during DJF and 5°S during JJA
  • Major reduction in precip near the equator during all seasons

… do fire aerosols alter the Hadley circulation?

from: Tosca et al., 2012

slide73

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Precipitation response - circulation changes?

  • Though precipitation declined globally, there were large decreases at the equator, countered by slight increases to the north and south.
  • Reductions over tropical forests = fires may increase their vulnerability to climate change

from: Tosca et al., 2012

slide74

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Hadley Circulation changes

  • Diagnose Hadley Circulation using mass meriodional stream function (),

Which is equal to the rate at which mass is being transported meridionally (with positive values indicating northward transport) between that pressure level and the top of the atmosphere

from: Tosca et al., 2012

slide75

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Hadley circulation changes, a summary

mid-troposphere heating from BC absorption

from: Tosca et al., 2012

slide76

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Hadley circulation changes, a summary

mid-troposphere heating from BC absorption

+

surface cooling (especially in equatorial regions)

from: Tosca et al., 2012

slide77

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Hadley circulation changes, a summary

mid-troposphere heating from BC absorption

+

surface cooling (especially in equatorial regions)

=

weakened equatorial convection

from: Tosca et al., 2012

slide78

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Hadley circulation changes, a summary

mid-troposphere heating from BC absorption

+

surface cooling (especially in equatorial regions)

=

weakened equatorial convection

climate response

shaded = upward velocities (convection)

unshaded = downward velocities (subsidence)

vertical velocity ()

from: Tosca et al., 2012

slide79

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Hadley circulation changes, a summary

mid-troposphere heating from BC absorption

+

surface cooling (especially in equatorial regions)

=

weakened equatorial convection

=

weaker Hadley circulation,

slight poleward expansion of descending branches

from: Tosca et al., 2012

slide80

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Hadley circulation changes

Annually-averaged 

  • Data from ECMWF matches well with output from CAM5

from: Tosca et al., 2012

slide81

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Hadley circulation changes

Annually-averaged 

  • Data from ECMWF matches well with output from CAM5
  • Weaking of the streamfunction near the equator - in regions of highest AOD.

from: Tosca et al., 2012

slide82

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • Climate response to smoke aerosols globally

Hadley circulation changes

Annually-averaged 

  • Data from ECMWF matches well with output from CAM5
  • Weaking of the streamfunction near the equator - in regions of highest AOD.
  • Slight expansion of the Hadley cell – consistent with Allen et al., (2012) and mid-latitude BC warming

from: Tosca et al., 2012

slide83

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work 5. Conclusions

  • Ecosystem response to fire

Total tropical forest ecosystem response to fire aerosols

  • Climatic changes (precipitation, temperature)
  • Direct deposition of nutrients (from aerosols) on ecosystems
  • Changes in albedo / surface fluxes
  • More diffuse radiation from aerosols
slide84

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work5. Conclusions

  • References

List of published manuscripts

Tosca, M. G., J. T. Randerson, C. S. Zender, M. G. Flanner and P. J. Rasch (2010), Do biomass burning aerosols intensify drought in equatorial Asia during El Niño?, Atmos. Chem. Phys., 10, 3515-3528, doi: 10.5194/acp-10-4515-2010.

Tosca, M. G., J. T. Randerson, C. S. Zender, D. L. Nelson, D. J. Diner and J. A. Logan (2011), Dynamics of fire plumes and smoke clouds associated with peat and deforestation fires in Indonesia, J. Geophys. Res., 116, D08207, doi: 10.1029/2010JD015148.

Zender, C. S., A. G. Krolewski, M. G. Tosca and J. T. Randerson (2011), Shape, reflectance, and age of smoke plumes from tropical biomass burning based on 2001-2009 MISR imagery, in review, Atmos. Chem. Phys.

Tosca, M. G.,J. T. Randerson and C. S. Zender (2012), Global impacts of contemporary smoke aerosols from landscape fires on climate and the Hadley circulation, submitted to Atmos. Chem. Phys.

slide85

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work5. Conclusions

  • Conclusions

In conclusion

  • Indonesian smoke plumes are injected into the boundary layer; burning occurs primarily in peat forests and during El Niño.
slide86

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work5. Conclusions

  • Conclusions

In conclusion

  • Indonesian smoke plumes are injected into the boundary layer; burning occurs primarily in peat forests and during El Niño.
  • More expansive smoke clouds are higher than plumes, impact climate via radiative and microphysical effects
slide87

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work5. Conclusions

  • Conclusions

In conclusion

  • Indonesian smoke plumes are injected into the boundary layer; burning occurs primarily in peat forests and during El Niño.
  • More expansive smoke clouds are higher than plumes, impact climate via radiative and microphysical effects
  • Direct fire aerosol forcing (in eq. Asia) during strong burning years reduces precipitation, increases drought stress and suggests a positive feedback between fire and drought.
slide88

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work5. Conclusions

  • Conclusions

In conclusion

  • Indonesian smoke plumes are injected into the boundary layer; burning occurs primarily in peat forests and during El Niño.
  • More expansive smoke clouds are higher than plumes, impact climate via radiative and microphysical effects
  • Direct fire aerosol forcing (in eq. Asia) during strong burning years reduces precipitation, increases drought stress and suggests a positive feedback between fire and drought.
  • Globally, fire aerosols contribute ~13% to total aerosol optical depth; reduce surface temperatures 0.3°C
slide89

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work5. Conclusions

  • Conclusions

In conclusion

Indonesian smoke plumes are injected into the boundary layer; burning occurs primarily in peat forests and during El Niño.

More expansive smoke clouds are higher than plumes, impact climate via radiative and microphysical effects

Direct fire aerosol forcing (in eq. Asia) during strong burning years reduces precipitation, increases drought stress and suggests a positive feedback between fire and drought.

Globally, fire aerosols contribute ~13% to total aerosol optical depth; reduce surface temperatures 0.3°C

Reduced equatorial convection (from surface cooling, atmospheric heating, indirect effects) weakens the Hadley circulation; mid-tropospheric BC warming increases tropical width

slide90

1. Introduction / Background2. Plumes in equatorial Asia3. Fire-climate feedbacks4. Future work5. Conclusions

  • Conclusions

Many thanks to…

Committee Chairs: Dr. Randerson & Dr. Zender

Committee Member: Dr. Yu

Co-authors: Mark Flanner (UMich), Dave Diner (JPL), Dave Nelson (JPL), Phil Rasch (PNNL), Jennifer Logan (Harvard)

Scott Capps (UCLA), Daniel Wang (SLAC), Guido van der Werf, Brendan Rogers, Claudia Pasquero, The Zender Group, The Randerson Group

UCI ESS staff, faculty and students…

Grateful for a NASA Earth Science Fellowship (NNX08AU90H)

slide91

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • 400 million years of fire on Earth

A brief history of fire

1 bya

100 mya

10 mya

1 mya

100 kya

10 kya

1 kya

100 ya

10 ya

1 ya

adapted from: Bowman et al., 2009

slide92

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • 400 million years of fire on Earth

A brief history of fire

global fire frequency

1 bya

100 mya

10 mya

1 mya

100 kya

10 kya

1 kya

100 ya

10 ya

1 ya

first fires ~400 mya

adapted from: Bowman et al., 2009

slide93

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • 400 million years of fire on Earth

A brief history of fire

global fire frequency

vegetation

1 bya

100 mya

10 mya

1 mya

100 kya

10 kya

1 kya

100 ya

10 ya

1 ya

C4 grasses

angiosperms

trees

terrestrial plants

first fires ~400 mya

adapted from: Bowman et al., 2009

slide94

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • 400 million years of fire on Earth

A brief history of fire

global fire frequency

vegetation

oxygen levels

1 bya

100 mya

10 mya

1 mya

100 kya

10 kya

1 kya

100 ya

10 ya

1 ya

C4 grasses

angiosperms

trees

terrestrial plants

first fires ~400 mya

adapted from: Bowman et al., 2009

slide95

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • 400 million years of fire on Earth

A brief history of fire

global fire frequency

vegetation

modern human dispersals

oxygen levels

The Americas

humans

Asia/Australia

Austronesian

Europe

1 bya

100 mya

10 mya

1 mya

100 kya

10 kya

1 kya

100 ya

10 ya

1 ya

C4 grasses

angiosperms

trees

terrestrial plants

satellite monitoring of fire

fire fighting/suppression

agricultural fire

first fires ~400 mya

foraging fire

domestic fire

human ancestors walk upright

adapted from: Bowman et al., 2009

slide96

1. Introduction / Background2. Plumes in equatorial Asia 3. Fire-climate feedbacks 4. Future work 5. Conclusions

  • 400 million years of fire on Earth

A brief history of fire

global fire frequency

?

vegetation

modern human dispersals

oxygen levels

The Americas

humans

Asia/Australia

climate (CO2 levels)

ENSO seasonality

Austronesian

Europe

“fire weather”

1 bya

100 mya

10 mya

1 mya

100 kya

10 kya

1 kya

100 ya

10 ya

1 ya

C4 grasses

angiosperms

trees

terrestrial plants

satellite monitoring of fire

fire fighting/suppression

agricultural fire

first fires ~400 mya

foraging fire

domestic fire

human ancestors walk upright

adapted from: Bowman et al., 2009