Fire climate interactions on the American Pacific Coast

Fire climate interactions on the American Pacific Coast

ACRE workshop

Meteoswiss, June 24 2008

Valérie Trouet

A.H. Taylor, A.M. Carleton, C.N. Skinner

0.0

0.5

1.0

1.5

2.0

2.5

1915 1925 1935 1945 1955 1965 1975 1985 1995

Millions of Hectares

From: Arno & Allison-Bunnell 2002From: Arno & Allison-Bunnell 2002

0.0

0.5

1.0

1.5

2.0

2.5

1915 1925 1935 1945 1955 1965 1975 1985 1995

Millions of Hectares

From: Arno & Allison-Bunnell 2002From: Arno & Allison-Bunnell 2002

Fire

Fire EnvironmentVaries in Time and Space

Fuels - Vegetation Canopy Surface Ground

Weather Wind HumidityDrought

Landform – Terrain Slope Aspect, Elevation, Hill - Slope - Drainage

FireEnvironment

FireEffects

Fire weather indicesFire growth potential, fire risk

Fire weather indicesFire growth potential, fire risk

ERC

• Fuel moisture

• NFDRS

• 19 (CA) + 14 (OR) RAWS

• 1973-2005

• fire season (July-Sep)

Haines Index

• range 2 – 6

• NCEP/NCAR (2.5°)

• daily (0000 UTC)

• 1961-2000Winkler et al. IJWF 2007

Haines Index climatology

Winkler et al. IJWF 2007

Mediterranean Climate AreaOregon and northern California

Trouet et al. GRL 2006

Interannual variability HI

HI, ERC vs. annual area burned

AAB Annual Winter Spring Summer FallFire

season

HI OR 0.58* 0.15 0.46* 0.39* -0.21 0.54*

CA 0.41* 0.15 0.36* 0.35* 0.03 0.41*

Days ≥ 5 OR 0.56* -0.02 0.36* 0.48* 0.01 0.56*

CA 0.39* 0.05 0.38* 0.35* 0.22 0.42*

Days ≤ 3 OR -0.6* -0.15 -0.45* -0.39* 0.12 -0.53*

CA -0.4* -0.14 -0.34* -0.35* -0.06 -0.4*

ERC OR 0.4*

CA 0.38*

HI, ERC vs. annual area burned

Trouet et al. TAC 2008

Temperature

HI

ERC

Precipitation

High Low

HI

ERC

Pacific North American (PNA) pattern

Pacific North American (PNA) pattern

Winter PNA –

summer fire weather

Conclusions

Severe fire weather years

• strong regional signal

• ~ widespread forest fires

• ~ synoptic scale circulation patterns

particularly PNA

Fire Scar Network

Fire Regimes and Climatic Variability in

the Mediterranean-Climate Areas of

California, Southwestern Oregon,

and Western Nevada

Fire Regimes and Climatic Variability in

the Mediterranean-Climate Areas of

California, Southwestern Oregon,

and Western Nevada

Fire regime reconstruction

1889 LW1879ME

1854 LE 1840 D

1828 D 1821 LE

1809 D 1799 D1793 D

1787 LW1781 ME

1775 D1771 D

1765 LW

Fire regime reconstruction

1500 1550 1600 1650 1700 1750 1800 1850 11500 1550 1600 1650 1700 1750 1800 1850 1900 1950 2000900 1950 20001500 1550 1600 1650 1700 1750 1800 1850 11500 1550 1600 1650 1700 1750 1800 1850 1900 1950 2000900 1950 2000

Airborne Research & Survey Facility