Numerical Modeling of Mountain Pine Beetle Transport by the Wind

1. Numerical Modeling of Mountain Pine Beetle Transport by the Wind Peter L. Jackson Brendan Murphy Benjamin Burkholder UNBC Environmental Science & Engineering With assistance from: Melissa Darney, Brenda Moore, Vera Lindsay Funded by: NRCan/CFS Mountain Pine Beetle Initiative 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

2. a) b) d) c) 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 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

3. 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 Aerobiology Vancouver, B.C., August 25, 2004

4. Dispersion is • active by flight over short distances / light wind (local scale: within stand over a few km) • passiveadvection 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 Aerobiology Vancouver, B.C., August 25, 2004

5. MPB Spread in BC • animation based on annual aerial survey of MPB “reds” (last year’s attack) 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

6. 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 Aerobiology Vancouver, B.C., August 25, 2004

7. Objectives • Identify synoptic weather patterns present during periods of MPB dispersal (P1.12 by Murphy and Jackson) • Identify fundamental relationships between terrain features, atmospheric flows and MPB fallout zones (P1.7 by Moore and Jackson) • Assess potential for physics-based meteorological and dispersion models to estimate MPB dispersal from one year to the next 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

8. 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 Aerobiology Vancouver, B.C., August 25, 2004

9. composite 2002 • 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” 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

10. Hasler Bear Lake Prince George 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

11. Hasler Bear Lake Prince George 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) 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

12. Time-height cross section • modelled wind and temperature from Chetwynd (east of the Rockies) • modelled wind and temperature from MacKenzie (west of the Rockies) 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

13. Hasler – BCMWLAP weather station NE of Rockies Bear Lake – BCMF weather station N of Prince George, W of Rockies Plaza 400 – BCMWLAP weather station in Prince George 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

14. Back Trajectories ending at 00Z 24 July 2002 (17:00 PDT) 105m 1100m 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

15. Conclusions & Future Work • RAMS seems capable of representing the conditions during MPB emergence and flight • Two approaches to future atmospheric modelling: • 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. • 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 Aerobiology Vancouver, B.C., August 25, 2004

16. 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 Aerobiology Vancouver, B.C., August 25, 2004

17. July 14-15, 2004 Peak emergence event 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

18. 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 Doppler radar image “clear air” returns are some type of insect  timing of appearance is consistent with peak emergence of MPB 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004

19. The End 16th Conference on Biometeorology and Aerobiology Vancouver, B.C., August 25, 2004