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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. Contributors University of Alabama in Huntsville. Central American Land Use Changes and Climate Ronald 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
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
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
Land use change disturbances Land use change impacts the local climate primarily by changing the surface energy budget. • Vegetation type • Surface roughness • Soil type • Soil moisture • Albedo • Land surface temperature Surface Energy Budget
1. Petén Basin – Guatemala Manoharan et al., 2009 • Characterized by low relief (<300m) • 30x30 km2 samples of forested deforested and partially forested region were picked
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%.
Results 2.64% of the overall region has been deforested from 2000 to 2008
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) • GEMRAMSsimulates 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).
March 8th, 2003 – 12 noon LT Forests Pastures Topography Temp 2m Forests Forests Pastures Pastures Sensible heat flux (W/m2) Latent heat flux (W/m2)
Circulation pattern along AB(March 23rd) Pasture Forest Pasture Forest Pasture Forest Pasture Pasture Forest Forest
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)>Precipforest(~25mm) PBLpasture < PBLforest Results
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.
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.
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
Next Step • Look at the corridors in high altitude regions