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Modelling medium and long-range movement of MPB using atmospheric models

Modelling medium and long-range movement of MPB using atmospheric models. Peter L. Jackson UNBC Environmental Science & Engineering With assistance from: Brendan Murphy, Ben Burkholder, Brenda Moore, Vera Lindsay

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Modelling medium and long-range movement of MPB using atmospheric models

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  1. Modelling medium and long-range movement of MPB using atmospheric models Peter L. Jackson UNBC Environmental Science & Engineering With assistance from: Brendan Murphy, Ben Burkholder, Brenda Moore, Vera Lindsay Funded by: NRCan/CFS Mountain Pine Beetle Initiative grant awarded to Jackson, Lindgren and Ackerman FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  2. Outline • Introduction / Motivation • Objectives / Outcomes • Methods • Synoptic Climatology Results Highlights • Atmospheric Modelling – Idealized Case • Atmospheric Modelling – Realistic Case • Information Needs… FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  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 FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  4. 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 FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  5. MPB fly on hot summer days • Warmest conditions usually occur under slack synoptic weather conditions  terrain-induced thermal circulations (e.g. mountain/valley winds, anabatic/katabatic flows) and steering of winds by terrain should determine the above-canopy, and the within-canopy air flow FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  6. Objectives • Identify synoptic weather patterns present during periods of MPB dispersal • Identify fundamental relationships between terrain features, atmospheric flows and MPB fallout zones • Assess potential for physics-based meteorological and dispersion models to estimate MPB dispersal from one year to the next FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  7. 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 FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  8. A basic step prior to modelling is to find the average environmental conditions present during MPB flight • The Synoptic weather pattern determines the atmospheric background conditions in which MPB emerge and move. • Average weather pattern(s) associated with MPB flight are found using compositing • This leads to an understanding of regional wind patterns FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  9. Synoptic Climatology • It is likely that passive transport will be most important when peak emergence is occurring • Peak emergence is associated with higher temperatures • Define HC2 as days with Tmax > 25 C, but < 30 C FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  10. 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” FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  11. Relationships between topographic features and MPB: interaction with atmospheric flows • Morice Lakes has detailed infestation inventory • General pattern of spread is increasing elevation of new attack each year • Will be simulating these cases in real terrain • Also used as “ground truth” for idealized terrain simulations FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  12. Idealized simulation • Vertical cross-section over a series of hills • One day is simulated from 5 am PDT to 4 am the next day, each frame is an hour • Temperature (colour) • Winds (arrows) • Diurnal variation and onset/collapse of up/downslope flows FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  13. Hasler Bear Lake Prince George Infestation East of Rockies – initiated in 2002: 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) FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  14. Back Trajectories ending at 00Z 24 July 2002 (17:00 PDT) 105m 1100m FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  15. Conclusions & Future Work • RAMS seems capable of representing the conditions during MPB emergence and flight • Approaches to future atmospheric modelling: • Continue idealized simulations in relation to terrain • “rules of thumb” for beetle spread on the landscape • Continue simulation / validation of case studies to predict where beetles go from one year to the next. • 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. • used as input to beetle spread scenarios models for forest managers to assess the impact of silvicultural and management practices FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  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… FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  17. July 14-15, 2004 Peak emergence event FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  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 FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

  19. The End FERIC/FORREX: Mountain Pine Beetle Research Update An Operational Perspective January 25, 2005

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