wavelength bands (1, 2, and 4). A sharp contrast in arid land characteristics can be
identified on both sides of the Israel–Egypt border. This contrast is a direct result of
different vegetation cover and biogenic crust percentage on both sides.
Miliaresis and Partsinevelos (2010) used monthly night-averaged LST derived from
MODIS throughout a year period (2006) in an attempt to segment the terrain of Egypt
into regions with different LST seasonal variability and represent them parametrically.
Regions with distinct spatial and temporal LST patterns were identified using several
clustering techniques that captured aspects of spatial, temporal, and temperature
homogeneity or differentiation. Segmentation was augmented by taking elevation,
morphological features, and land cover information into consideration. Analyses of
these data showed that the lowland northern coast region of Egypt along the Mediterranean Sea corresponds to the coolest clusters, indicating a latitude/elevation dependency of seasonal LST variability. Conversely, for inland regions, elevation and terrain
dissection plays a key role in LST seasonal variability, while an east-to-west variability
of spatial distribution in clusters is evident. Lastly, elevation-biased clustering revealed
annual LST differences among the regions with the same physiographic and terrain
characteristics. Thermal terrain segmentation outlined temporal variation of LST during
the year period as well as the spatial distribution of LST zones.
3.8 THERMAL ENERGY THEORY AS APPLIED TO ECOLOGICAL
THERMODYNAMICS
The concept of ecological thermodynamics provides a quantification of surface
energy fluxes for landscape characterization in relation to the overall amount of
energy input and output from specific land cover types. Ecological thermodynamics
was introduced in the Quattrochi and Luvall (1999) Landscape Ecology paper, but
here we present a more thorough understanding of the techniques and methods
embodied within this concept to offer an updated and clearer understanding of its
utility and virtues
Terrestrial ecosystem surface temperatures have been measured using airborne and
satellite sensors for several decades. Using NASA’s Thermal Infrared Multispectral
Scanner (TIMS), Luvall and his co-workers (Luvall and Holbo, 1989, 1991; Luvall
et al. 1990) have documented ecosystem energy budgets for tropical forests, midlatitude varied ecosystems, and semiarid ecosystems. These data show that within a
given biome type and under similar environmental conditions (air temperature,
relative humidity, winds, and solar irradiance), the more developed the ecosystem,
the cooler its surface temperature and the more degraded the quality of its reradiated
energy. These data suggest that ecosystems develop structure and function that
degrade the quality of the incoming energy more effectively; that is, they degrade
more exergy,
9 which agrees with the predictions of nonequilibrium thermodynamic
9 In thermodynamics, the exergy of a system is the maximum work available through any process that
brings the system into equilibrium with a heat reservoir (environment). Exergy is the energy available for
use. See Fraser and Kay (2004) for a discussion of exergy in an ecological context.
THERMAL ENERGY THEORY AS APPLIED TO ECOLOGICAL THERMODYNAMICS
47
identified on both sides of the Israel–Egypt border. This contrast is a direct result of
different vegetation cover and biogenic crust percentage on both sides.
Miliaresis and Partsinevelos (2010) used monthly night-averaged LST derived from
MODIS throughout a year period (2006) in an attempt to segment the terrain of Egypt
into regions with different LST seasonal variability and represent them parametrically.
Regions with distinct spatial and temporal LST patterns were identified using several
clustering techniques that captured aspects of spatial, temporal, and temperature
homogeneity or differentiation. Segmentation was augmented by taking elevation,
morphological features, and land cover information into consideration. Analyses of
these data showed that the lowland northern coast region of Egypt along the Mediterranean Sea corresponds to the coolest clusters, indicating a latitude/elevation dependency of seasonal LST variability. Conversely, for inland regions, elevation and terrain
dissection plays a key role in LST seasonal variability, while an east-to-west variability
of spatial distribution in clusters is evident. Lastly, elevation-biased clustering revealed
annual LST differences among the regions with the same physiographic and terrain
characteristics. Thermal terrain segmentation outlined temporal variation of LST during
the year period as well as the spatial distribution of LST zones.
3.8 THERMAL ENERGY THEORY AS APPLIED TO ECOLOGICAL
THERMODYNAMICS
The concept of ecological thermodynamics provides a quantification of surface
energy fluxes for landscape characterization in relation to the overall amount of
energy input and output from specific land cover types. Ecological thermodynamics
was introduced in the Quattrochi and Luvall (1999) Landscape Ecology paper, but
here we present a more thorough understanding of the techniques and methods
embodied within this concept to offer an updated and clearer understanding of its
utility and virtues
Terrestrial ecosystem surface temperatures have been measured using airborne and
satellite sensors for several decades. Using NASA’s Thermal Infrared Multispectral
Scanner (TIMS), Luvall and his co-workers (Luvall and Holbo, 1989, 1991; Luvall
et al. 1990) have documented ecosystem energy budgets for tropical forests, midlatitude varied ecosystems, and semiarid ecosystems. These data show that within a
given biome type and under similar environmental conditions (air temperature,
relative humidity, winds, and solar irradiance), the more developed the ecosystem,
the cooler its surface temperature and the more degraded the quality of its reradiated
energy. These data suggest that ecosystems develop structure and function that
degrade the quality of the incoming energy more effectively; that is, they degrade
more exergy,
9 which agrees with the predictions of nonequilibrium thermodynamic
9 In thermodynamics, the exergy of a system is the maximum work available through any process that
brings the system into equilibrium with a heat reservoir (environment). Exergy is the energy available for
use. See Fraser and Kay (2004) for a discussion of exergy in an ecological context.
THERMAL ENERGY THEORY AS APPLIED TO ECOLOGICAL THERMODYNAMICS
47