The interaction between terrestrial ecosystems and the atmosphere continues to be
a central research theme within climate, hydrology, and ecology communities. This
interest is stimulated by research issues pertinent to both the fundamental laws and the
hierarchy of scales. To further explorer such topics over various spatial and temporal
domains, in this study, biosphere-atmosphere interactions are studied at two different
scales, leaf-to-canopy and canopy-to-atmospheric boundary-layer (ABL) scales, by
utilizing both models and long-term measurements collected from the Duke Forest
AmeriFlux sites.
For the leaf-to-canopy scale, two classical problems motivated by contemporary
applications are considered: (1) ‘inverse problem’ – determination of nighttime
ecosystem respiration, and (2) forward problem – estimation of two-way interactions
between leaves and their microclimate ‘’. An Eulerian inverse approach was developed to
separate aboveground respiration from forest floor efflux using mean CO2 concentration
and air temperature profiles within the canopy using detailed turbulent transport theories.
The forward approach started with the assumption that canopy physiological, drag, and
radiative properties are known. The complexity in the turbulent transport model needed
for resolving the two-way interactions was then explored. This analysis considered a
detailed multi-layer ecophysiological and radiative model embedded in a hierarchy of
Eulerian turbulent closure schemes ranging from well-mixed assumption to third order
closure schemes with local thermal-stratification within the canopy.
For the canopy-to-ABL scale, this study mainly explored problems pertinent to
the impact of the ecophysiological controls on the regional environment. First, the
possible combinations of water states (soil moisture and atmospheric humidity) that
trigger convective rainfall were investigated, and a distinct ‘envelope’ of these
combinations emerged from the measurements. Second, an analytical model as a function
of atmospheric and ecophysiological properties was proposed to examine how the
potential to trigger convective rainfall shifts over different land-covers. The results
suggest that pine plantation, whose area is projected to dramatically increase in the
Southeastern US (SE), has greater potential to trigger convective rainfall than the other
two ecosystems. Finally, the interplay between ecophysiological and radiative attributes
on surface temperature, in the context of regional cooling/warming, was investigated for
projected land-use changes in the SE region. / Dissertation
| Identifer | oai:union.ndltd.org:DUKE/oai:dukespace.lib.duke.edu:10161/171 |
| Date | 14 March 2007 |
| Creators | Juang, Jehn-Yih |
| Contributors | Katul, Gabriel, Oren, Ram, Kasibhatla, Prasad, Albertson, John, Porporato, Amilcare |
| Source Sets | Duke University |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
| Format | 4638567 bytes, application/pdf |
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