Ronald M. Welch (PI)

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Environmental Stability of Forest Corridors in
the Mesoamerican Biological Corridor (MBC) Region

• Ronald M. Welch (PI)
• Vani Starry Manoharan
• University of Alabama in Huntsville

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ContributorsUniversity of Alabama in Huntsville

• Central American Land Use Changes and Climate
• Ronald Welch, PI
• Vani Starry Manoharan
• Robert Lawton
• Tom Sever
• Daniel Irwin
• - Modeling land use change and climate using
  GEMRAMS
• Aaron Song
• Udayasankar Nair
• Precipitation Processes over forested and
  deforested regions
• John Mecikalski
• Matt Wingo

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Proposed Mesoamerican Biological Corridor
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Primary Objective

• Determine the extent of which land use change
  disturbances have affected and are affecting
  regional and local climatic conditions
• in ways that influence the environmental
  stability of protected regions and proposed
  corridors in the Mesoamerican Biological Corridor

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Land use change disturbances

• Land use change impacts the local climate
  primarily by changing the surface energy
  budget.

1. Vegetation type
2. Surface roughness
3. Soil type
4. Soil moisture
5. Albedo
6. Land surface temperature

Surface Energy Budget
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1. Petén Basin Guatemala
Manoharan et al., 2009

• Characterized by low relief (lt300m)
• 30x30 km2 samples of forested deforested and
  partially forested region were picked

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Data and methodology

• MODIS Level 1B calibrated radiance data for March
  to September, 2000 and 2008 are used to derive
  Normalized Difference Vegetation Indices (NDVI),
  surface temperatures and soil moisture values.
• March - April ? peak of dry season
  Ray et al., 2006
• May - July ? dry to wet season
• August - September ? peak of the wet season.
• MODIS channels 1 (0.645mm visible red) and 2
  (0.858mm near infra red) are used to derive
  NDVI values, and channel 31 (11.3mm) is used for
  the land surface temperature retrievals.
• A supervised maximum likelihood classification
  was performed to estimate the rate of
  deforestation.

Pixels are broadly classified into two classes as
forested and deforested regions, and these
classes are well-separated with an accuracy of
94.
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Results
Partially Deforested 10 11 12
2000 17.7 12.9 13.4
2008 2.9 8.3 4.7
2.64 of the overall region has been deforested
from 2000 to 2008
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2. GEMRAMSImpacts of deforestation on the
proposed corridors in northern Guatemala Welch
et al., 2010 (submitted)

• GEMRAMS Regional Atmospheric Modeling System
  (RAMS) coupled with General Energy and Mass
  Transport Model (GEMTM) (Beltrán et al., 2005)
• GEMRAMS simulates dynamic interactions between
  the atmosphere and growing canopy
• Use GEMRAMS to simulate the vegetation in the
  Petén areas for half forested and half deforested
  scenario (dry and wet day during March 2003).

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March 8th, 2003 12 noon LT
Forests
Pastures
Temp 2m
Topography
Forests
Forests
Pastures
Pastures
Latent heat flux (W/m2)
Sensible heat flux (W/m2)
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Circulation pattern along AB (March 23rd)
Pasture
Forest
Pasture
Pasture
Forest
Forest
Pasture
Pasture
Forest
Forest
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Results

• Dry day
• LHforest and LHpasture very low (30W/m2)
• SH 3 to 10 times LH
• PBL 2000m(afternoon)
• Cloud cover 13
• No precipitation

• Convective Day
• Convection started early over the pastures
• By mid-day convection was over forest and pasture
• Later noon convection decreases over F and P, but
  much faster over F
• LH very large 700 W/m2
• Cloud cover higher over P
• Precippasture (60mm)gtPrecipforest (25mm)
• PBLpasture lt PBLforest

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Results

• In terms of the sustainability of the lowland
  corridors, forested corridors will experience
  warmer conditions due to higher temperatures in
  surrounding deforested areas.
• Precipitation The forested corridors will
  receive higher than normal precipitation rates
  due to the fact that surrounding deforested
  regions generate higher convective activity.
• The above scenario implies a climate tipping
  point will not occur in the proposed corridor
  regions which would threaten their stability and
  sustainability.

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Cloud top cooling rate (GOES E)
There were no significant differences in cloud
top height in the forested and deforested regions
in either the dry or wet seasons, but deep
convection is more prevalent in the dry season.
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Conclusion

• Deforestation is a continuing process
• Partially deforested regions in Guatemala ? 9.3
  decrease in forests from 2000-2008
• Forested regions have a relatively stable
  environment
• Forested corridors in low lands are not
  threatened by the surrounding deforestation

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Next Step

• Look at the corridors in high altitude regions