Influence of greater Nitrogen Deposition in Missoula, MT

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Influence of greater Nitrogen Deposition in
Missoula, MT

• Anne Trainor
• Exercise 3
• October 2, 2007

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Introduction

• Substantial increase of nitrogen deposition since
  the industrial boom
• large impacts on forested ecosystems.
• Objective
• Examine how a significant increase in nitrogen
  could influence annual and seasonal nutrient
  cycling dynamics within an evergreen forest.

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Study System

• Missoula, MT
• Meteorological Data 1950-1993
• 1 m Loamy Soil
• 30 sandy, 50 silt, 20 clay
• Evergreen Needleleaf system
• Used all defaults

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Modeling

• Biome-BGC (version 4.1.2)
• Carbon levels constant at default value
• (294.842 ppm)
• Consisted of 3 runs for 88 years
• A) Spin up Default pre-industrial nitrogen level
  (0.0001 kgm2yr1)
• B) Typical Nitrogen Based off previous Spinup
  ran simulation with default pre-industrial
  nitrogen level (0.0001 kgm2yr1)
• C) Increased Nitrogen Based off original Spinup
  ran simulation with Nitrogen increased to 0.005
  kgm2yr1

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Methods

• Selected a consecutive dry and wet year to
  compare extremes

1980 and 1981
1973 and 1974
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Relevant Variables Modeled
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