16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Numerical Modeling of Mountain Pine Beetle Transport

by the WindPeter L. Jackson

Brendan Murphy

Benjamin Burkholder

UNBC Environmental Science & EngineeringWith assistance from:

Melissa Darney, Brenda Moore, Vera Lindsay

Funded by: NRCan/CFS Mountain Pine Beetle Initiative

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Photo credits (clockwise from top): a) http://www.ecoforestry.ca/jrnl_artilces/images/17-1-Partridge-Reuters.jpg

b&c) http://www.sparwood.bc.ca/forest/untreated.htm d) http://www.pfc.forestry.ca/entomology/mpb/management/

silviculture/images/valley_lrg.jpg

a)

c)

b)

d)

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Introduction / Motivation

• MBP infestation has reached epidemic proportions in central BC affecting 4.2 million ha and 176 million m3 of timber

• Emergence and flight in summer after 3 days of Tmax > 18 ºC but < 30°C

• Peak emergence for successful mass-attack occurs when Tmax > 25 ºC

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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• Dispersion is – active by flight over short distances / light wind

(local scale: within stand over a few km)– passive advection due to winds and turbulence

above and within canopy (landscape scale: between stands perhaps 10-100 km)

• Passive transport allows epidemic to spread rapidly over great distances little is known about passive transport and this is the focus of our work

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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MPB Spread in BC• animation based on annual aerial survey of MPB “reds” (last year’s attack)

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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MPB Spread in BC• eastward movement of the “front”

• spread of MPB limited by the -40 ºC annual minimum isotherm

•climate chg moves -40 ºC northeastward

• concern over MPB crossing the Rocky Mountains

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Objectives1. Identify synoptic weather patterns

present during periods of MPB dispersal (P1.12 by Murphy and Jackson)

2. Identify fundamental relationships between terrain features, atmospheric flows and MPB fallout zones (P1.7 by Moore and Jackson)

3. Assess potential for physics-based meteorological and dispersion models to estimate MPB dispersal from one year to the next

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Methods• Passive transport of MPB is similar to

transport and dispersion of air pollutants

• CSU Regional Atmospheric Modeling System (RAMS) to simulate the atmosphere (wind, temperature, humidity, pressure, etc. on a nested 3D grid)

• The meteorological fields from RAMS will be used to calculate trajectories

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Evolution of HC2 composite 500 hPa and Lifted Index (shaded) based on NCEP Reanalysis data

• as upper ridge passes atmosphere becomes moderately unstable (Lifted index negative) resulting in “thermals”

570

576

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-0.5

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ight

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Te

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Day-3 Day-2 Day-1 Day 0 Day+1 Day+2 Day+3

H(500hPa)

LFTX

558

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-2

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Jul 21 Jul 22 Jul 23 Jul 24 Jul 25 Jul 26 Jul 27

H(500hPa)

LFTX

composite

2002

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Hasler

Bear Lake

Prince George

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Hourly output from RAMS simulation at model level 2 (~40 m AGL), from grid 4 at 3 km horizontal resolution (only every 2nd wind vector shown)

Hasler

Bear Lake

Prince George

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Time-height cross section

• modelled wind and temperature from MacKenzie (west of the Rockies)

• modelled wind and temperature from Chetwynd (east of the Rockies)

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Bear Lake – BCMF weather station N of Prince George, W of Rockies

Plaza 400 – BCMWLAP weather station in Prince George

Hasler – BCMWLAP weather station NE of Rockies

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Back Trajectories ending at 00Z 24 July 2002 (17:00 PDT)

105m

1100m

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Conclusions & Future Work• RAMS seems capable of representing the

conditions during MPB emergence and flight• Two approaches to future atmospheric modelling:

1. Continue simulation and validation of case studies to predict where beetles go from one year to the next. To be used in real time for planning beetle control strategies.

2. Ensemble trajectories created for each grid point in the landscape, based on a runs of a large number of past peak emergence heating cycle events. To be used as input to beetle spread scenario planning models that are primarily for forest managers to assess the impact of silvicultural and management practice.

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Information Needs

• Need beetle validation / initialization data:– More documented MPB flight / emergence

periods, ideally at daily resolution– More “case studies” of between stand

movement for validation (especially isolated populations)

– MPB time in flight, height of flight – how many fly above the canopy? – Prince George Doppler Radar holds intriguing promise…

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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July 14-15, 2004 Peak emergence event

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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Doppler radar image

“clear air” returns are some type of insect timing of appearance is consistent with peak emergence of MPB

0.5 degree PPI radar scan from 00Z 15 July 2004

(1700 PDT 14 July 2004)

Reflectivity < 0 DBZ

Echo tops 800 – 1500 m AGL

16th Conference on Biometeorology and AerobiologyVancouver, B.C., August 25, 2004

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The End