Research Interests: Environmental Science, Geology, Oceanography, Coastal Erosion, Erosion, and 3 moreStorm, Sediment, and Shore
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Tropical overshooting convection has a strong impact on both heat budget and moisture distribution in the upper troposphere and lower stratosphere, and it can pose a great risk to aviation safety. Cloud-top height is one of the essential... more
Tropical overshooting convection has a strong impact on both heat budget and moisture distribution in the upper troposphere and lower stratosphere, and it can pose a great risk to aviation safety. Cloud-top height is one of the essential concerns of overshooting convection for both the climate system and the aviation weather forecast. The main purpose of our work is to verify the application of the machine learning method, taking the random forest (RF) model as an instance, in overshooting cloud-top height retrieval from Himawari-8 data. By using collocated CloudSat observations as a reference, we utilize several infrared indicators of Himawari-8 that are commonly recognized to relate to cloud-top height, along with some temporal and geographical parameters (latitude, month, satellite zenith angle, etc.), as predictors to construct and validate the model. Analysis of variable importance shows that the brightness temperature of 6.2 um acts as the dominant predictor, followed by satel...
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We developed an entraining parcel approach that partitions parcel buoyancy into contributions from different processes (e.g., adiabatic cooling, condensation, freezing, and entrainment). Applying this method to research-quality radiosonde... more
We developed an entraining parcel approach that partitions parcel buoyancy into contributions from different processes (e.g., adiabatic cooling, condensation, freezing, and entrainment). Applying this method to research-quality radiosonde profiles provided by the Atmospheric Radiation Measurement (ARM) program at six sites, we evaluated how atmospheric thermodynamic conditions and entrainment influence various physical processes that determine the vertical buoyancy structure across different climate regimes as represented by these sites. The differences of morning buoyancy profiles between the deep convection (DC)/transition cases and shallow convection (SC)/nontransition cases were used to assess preconditions important for shallow-to-deep convection transition. Our results show that for continental sites such as the U.S. Southern Great Plains (SGP) and west-central Africa, surface conditions alone are enough to account for the buoyancy difference between DC and SC cases, although ...
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Mike Waldon (DOI Everglades Program Team) gave a presentation on his research: “Near Zeroth Order Sulfate Disappearance Rate Estimated using Models of the Arthur R. Marshall Loxahatchee National Wildlife Refuge”. He described how the... more
Mike Waldon (DOI Everglades Program Team) gave a presentation on his research: “Near Zeroth Order Sulfate Disappearance Rate Estimated using Models of the Arthur R. Marshall Loxahatchee National Wildlife Refuge”. He described how the hydrology of the Loxahatchee area (aka WCA1) has been altered from a predominantly sheet-flow system to a riparian wetland, and that the water chemistry had been altered from a rainfall-fed system to one with elevated chloride, sulfate, and total P. He stated that the input of canal water was the primary source of sulfate contamination in the marsh interior. The rate of sulfate disappearance (reduction flux) was relatively constant (~15 g/m2/yr) and was not sulfate limited. The results of their efforts to model sulfate concentrations in the canals and the marsh suggested that a first order model required a 20-fold adjustment in the rate constant (the effective sulfate disappearance rate in m/yr) to fit data from the canals to the marsh interior, while a...
Research Interests: Australia, Biology, China, Medicine, Sequence Analysis, and 15 moreBiological Sciences, Phylogeny, Sequence alignment, Cluster Analysis, Structure Analysis, Secondary Structure, Molecular Characterization, Viroids, Genetic variation, Base Sequence, In Silico, Molecular Sequence Data, Sequence homology, cDNA cloning, and Medical and Health Sciences
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Research Interests: History, Geography, Remote Sensing, China, Global Positioning System, and 15 moreModels, Far East, Aerial Photography, Change detection, Landforms, Topography, Geomatic Engineering, Satellite Imagery, Differential Global Positioning System, Accuracy, Chine, High Resolution, Precision, Orthophoto, and Orthorectification
Research Interests: Landscape Ecology, Monte Carlo, Human impacts on ancient environments, Land Use Change, Biological Sciences, and 15 moreEnvironmental Sciences, Land Cover, Ecosystems, Uncertainty Estimation, Anthropocene, Spatial Scale, Landscape change, Tree Planting, Change process, Environmental Impact, High Resolution, Surface Area, Rural Area, Monte Carlo Method, and Stratified sampling
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Research Interests: Geography, Agricultural Development, Agricultural Policy, Land management, Market Orientation, and 15 moreLand Use Change, Land Use History, Environmental Sciences, Land Cover, Case Study, Landscape change, Land cover change, Historical Data, High Resolution, Management Practice, Landscape Structure, Agricultural landscape, Elsevier, Landscape Heterogeneity, and Monte Carlo Method
Purpose Village landscapes, which integrate small-scale agriculture with housing, forestry and a host of other land use practices, cover more than 2×106 km2 across China. Village lands tend to be managed at very fine spatial scales (≤30... more
Purpose Village landscapes, which integrate small-scale agriculture with housing, forestry and a host of other land use practices, cover more than 2×106 km2 across China. Village lands tend to be managed at very fine spatial scales (≤30 m), with managers altering soil fertility and even terrain by terracing, irrigation, fertilizing, and other land use practices. Under these conditions, accumulation of excess phosphorous in soils has become important contributor to eutrophication of surface waters across China’s densely populated village landscapes. The aim of this study was to investigate relationships between fine-scale patterns of agricultural management and soil total phosphorus (STP) within China’s village landscapes. Materials and methods First, China’s village landscapes
Barrier islands are dynamic environments because of their position along the marine–estuarine interface. Geomorphology influences habitat distribution on barrier islands by regulating exposure to harsh abiotic conditions. Researchers have... more
Barrier islands are dynamic environments because of their position along the marine–estuarine interface. Geomorphology influences habitat distribution on barrier islands by regulating exposure to harsh abiotic conditions. Researchers have identified linkages between habitat and landscape position, such as elevation and distance from shore, yet these linkages have not been fully leveraged to develop predictive models. Our aim was to evaluate the performance of commonly used machine learning algorithms, including K-nearest neighbor, support vector machine, and random forest, for predicting barrier island habitats using landscape position for Dauphin Island, Alabama, USA. Landscape position predictors were extracted from topobathymetric data. Models were developed for three tidal zones: subtidal, intertidal, and supratidal/upland. We used a contemporary habitat map to identify landscape position linkages for habitats, such as beach, dune, woody vegetation, and marsh. Deterministic accu...
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Based on analysis of the different kinds of calculation methods on solar radiation, a simple, practical and easy operative model was built to estimate daily solar radiation in China. The inputs of the model needed were the sunshine hours... more
Based on analysis of the different kinds of calculation methods on solar radiation, a simple, practical and easy operative model was built to estimate daily solar radiation in China. The inputs of the model needed were the sunshine hours and geological information of calculating stand. The simulated results for 9 representative stations in the different regions of China were compared and statistically validated with the observation values. The results showed that the simulated solar radiations had significantly related to the observation values (R~(2)=0.81-0.93). The average error of calculation was 16.5%, the average absolute and the standard deviation were 0.77, 2.09 and 2.65 MJ m~(-2) d~(-1) respectively. The simulation parameters needed to be adjusted in the special regions.
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Soil pore water salinity plays a very important role in determining the distribution of vegetation, plant productivity and biogeochemical processes in estuarine ecosystems. Pore water salinity gradients and salinity-vegetation... more
Soil pore water salinity plays a very important role in determining the distribution of vegetation, plant productivity and biogeochemical processes in estuarine ecosystems. Pore water salinity gradients and salinity-vegetation associations in salt marshes have often been observed but rarely explained. A quantitative and systematic study on the pore water salinity distribution in salt marshes is not only critical to the understanding of the phenomenon itself but also to the use of the phenomenon as a convenient ecological and environmental change indicator. In this research, we developed a salt marsh pore water salinity model based on a salt and water balance model with modifications to several key features (e.g., applying the Penman-Monteith equation to calculate ET for different climate zones) to examine the impacts of climate, tidal forcing, soil, vegetation, and topography on pore water salinity distribution along elevation in the Atlantic and Gulf coastal regions. This model was...
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COMPARTMENT DELINEATION FOR A WETLAND WATER QUALITY MODEL IN THE NORTHERN EVERGLADES, FLORIDA, USA A water-quality model application to large geographical areas typically involves the spatial aggregation of sub-areas into compartments... more
COMPARTMENT DELINEATION FOR A WETLAND WATER QUALITY MODEL IN THE NORTHERN EVERGLADES, FLORIDA, USA A water-quality model application to large geographical areas typically involves the spatial aggregation of sub-areas into compartments which are assumed within the model to be uniform. Model compartments often are delineated using available data and professional judgment. Compartment delineation affects the accuracy of hydrodynamic and water quality modeling by subjectively grouping sub-areas of similar characteristics. In this research, we applied cluster analysis (CA) to objectively determine the number of compartments and to spatially delineate compartments with similar descriptive features for water-quality modeling. Here, surface-water quality data collected in the A.R.M. Loxahatchee National Wildlife Refuge (Refuge), Florida were analyzed using CA of concentrations of chloride, total phosphorus, sulfate, and calcium measured at sites distributed throughout the Refuge. The Refuge...
In this study,we examined interactions between landscape structure,land management and soil total nitrogen(TN;top 30 cm) and total phosphorus(TP;top 30 cm) within the densely populated rural landscapes of the Yangtze Plain,based on an... more
In this study,we examined interactions between landscape structure,land management and soil total nitrogen(TN;top 30 cm) and total phosphorus(TP;top 30 cm) within the densely populated rural landscapes of the Yangtze Plain,based on an intensive field study in a regionally-representative sample cells in Yixing County.The rural landscapes were mapped at a high spatial resolution and classified to ecologically-distinct features(ecotopes) by the direct interpretation and field validation of features in 2002 IKONOS imagery using a standardized mapping procedure.Then the samples of soils and sediments were collected for analysis at random points within ecotope selected by a cluster distance weighting stratified sampling design.The five most extensive land use/land cover categories in the Yangtze Plain were paddy,aquaculture,built structures with impervious cover,rainfed annual cropland and fallow water,which occupied 82.9% of the total area,contained 82.6% of the total nitrogen and 80.8% of the total phosphorus stored in the region′s rural landscapes,respectively.Regional scaling analysis indicated that 85.24×103 km2 of Yangtze Plain rural landscapes sequestered 29.87 Tg of the total nitrogen and 19.79 Tg of the total phosphorus,of which 51% and 45% were in paddy land respectively(15.26 Tg of TN and 9.13 Tg of TP),covering 45.5% of the region′s total surface area(38.93×103 km2).Regional estimates of landscape class areas,soil total nitrogen and soil total phosphorus were made by upscaling data obtained from the sample cells by using a multivariate regional optimization procedure combined with bootstrapping and Monte Carlo uncertainty analysis.Then the role of land use/land cover in determining local total nitrogen and total phosphorus patterns and the regional consequences of these patterns were revealed across a densely populated rural region of China′s Yangtze Plain.This fine-scale approach to investigating land management practices and their impacts on total nitrogen,total phosphorus and other ecosystem properties offers significant advantages of accuracy rate over conventional lower-resolution(30-1000m) methods for land cover.
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Conclusions/Lessons Learned * Approach in model development must not be overly rigid or constrained * Sub-regional models are appropriate for addressing many restoration design and management questions * Simulation of regulation schedule... more
Conclusions/Lessons Learned * Approach in model development must not be overly rigid or constrained * Sub-regional models are appropriate for addressing many restoration design and management questions * Simulation of regulation schedule adds to model credibility & utility * Modeling multiple constituents increases credibility of models * Approach developing a suite of models at varying spatial resolutions and levels of complexity is useful * Modeling of TP using DMSTA dynamics & calibration parameters provides reliable simulation * Technical Advisory Panel + internal review + agency & public input improved the models * Models add to our understanding of importance of individual causal mechanisms Future Challenges * These 4 Refuge models, alone or combined with other analyses are available, but judgment & understanding are essential for interpretation * Responsibility for project alternative analysis must be determined/accepted * Analogous modeling in other WCAs & the ENP is feasibl...
... Modeling surface wind effects on subtidal salinity in Apalachicola Bay. Estuarine, Coastal and Shelf Science, 55(1), 33−46; Huang, W., Sun, H., Nnaji, S., & Jones, K. (2002). Tidal hydrodynamics in a multiple inlet... more
... Modeling surface wind effects on subtidal salinity in Apalachicola Bay. Estuarine, Coastal and Shelf Science, 55(1), 33−46; Huang, W., Sun, H., Nnaji, S., & Jones, K. (2002). Tidal hydrodynamics in a multiple inlet estuary: Apalachicola Bay. ...
Research Interests: Management, Cartography, Environmental Science, Remote Sensing, Coastal Management, and 15 moreEvaluation, Risk assessment, Concentration, Risk Analysis, Ecosystems, Sediments, Geomatic Engineering, Atmospheric Correction, Sediment, Satellite Imagery, Environmental Impact, Regression Model, Spatial Variation, Risk Assessment, and Q
Chromium compounds have been known to be highly toxic in biological systems and to some individuals act as strong allergens. A chromium processing plant in Tianjin city has been abandoned for many years and the chromium residue has been... more
Chromium compounds have been known to be highly toxic in biological systems and to some individuals act as strong allergens. A chromium processing plant in Tianjin city has been abandoned for many years and the chromium residue has been dispersed into the nearby soil. This study was designed to detect the genotoxicity of contaminated soil samples collected at various distances of 100 to 1000 m from the source using the Vicia faba root micronucleus test. Water solutions extracted from the soil samples were used to treat the roots of the Vicia beans. Micronuclei frequencies observed from the root meristems were used to determine the degree of genotoxicity. Micronuclei frequencies of the contaminated soil samples show linear dose responses to chromium contents in the soil, which were inversely proportional to the distance from the source.
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ABSTRACT Leaves from mangrove forests are often considered efficient in the use of water during photosynthesis, but less is known about whole-tree and stand-level water use strategies. Are mangrove forests as conservative in water use as... more
ABSTRACT Leaves from mangrove forests are often considered efficient in the use of water during photosynthesis, but less is known about whole-tree and stand-level water use strategies. Are mangrove forests as conservative in water use as experimental studies on seedlings imply? Here, we apply a simple model to estimate stand water use (S), determine the contribution of S to evapotranspiration (ET), and approximate the distribution of S versus ET over annual cycles for three mangrove forests in southwest Florida, USA. The value of S ranged from 350 to 511 mm year−1 for two mangrove forests in Rookery Bay to 872 mm year−1 for a mangrove forest along the Shark River in Everglades National Park. This represents 34–49% of ET for Rookery Bay mangroves, a rather conservative rate of S, and 63–66% of ET for the Shark River mangroves, a less conservative rate of S. However, variability in estimates of S in mangroves is high enough to require additional study on the spatial changes related to forest structural shifts, different tidal regimes, and variable site-specific salinity concentrations in multiple mangrove forests before a true account of water use conservation strategies can be understood at the landscape scale. Evidence does suggest that large, well-developed mangrove forests have the potential to contribute considerably to the ET balance; however, regionally most mangrove forests are much smaller in stature in Florida and likely contribute less to regional water losses through stand-level transpiration.
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ABSTRACT Chen, Q.; Wang, H.; Wang, L.; Tawes, R., and Rollman D., 2014. Predicting the impacts of tropical cyclones and sea-level rise on beach mouse habitat. Alabama beach mouse (ABM) (Peromyscus polionotus ammobates) is an important... more
ABSTRACT Chen, Q.; Wang, H.; Wang, L.; Tawes, R., and Rollman D., 2014. Predicting the impacts of tropical cyclones and sea-level rise on beach mouse habitat. Alabama beach mouse (ABM) (Peromyscus polionotus ammobates) is an important component of the coastal dune ecosystem along the Gulf of Mexico. Due to habitat loss and degradation, ABM is federally listed as an endangered species. In this study, we examined the impacts of storm surge and wind waves, which are induced by hurricanes and sea-level rise (SLR), on the ABM habitat on Fort Morgan Peninsula, Alabama, using advanced storm surge and wind wave models and spatial analysis tools in geographic information systems (GIS). Statistical analyses of the long-term historical data enabled us to predict the extreme values of winds, wind waves, and water levels in the study area at different return periods. We developed a series of nested domains for both wave and surge modeling and validated the models using field observations of surge hydrographs and high watermarks of Hurricane Ivan (2004). We then developed wave atlases and flood maps corresponding to the extreme wind, surge and waves without SLR and with a 0.5 m of SLR by coupling the wave and surge prediction models. The flood maps were then merged with a map of ABM habitat to determine the extent and location of habitat impacted by the 100-year storm with and without SLR. Simulation results indicate that more than 82% of ABM habitat would be inundated in such an extreme storm event, especially under SLR, making ABM populations more vulnerable to future storm damage. These results have aided biologists, community planners, and other stakeholders in the identification, restoration and protection of key beach mouse habitat in Alabama. Methods outlined in this paper could also be used to assist in the conservation and recovery of imperiled coastal species elsewhere.
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Fertilizer application has the potential to promote the sequestration of carbon (C) and nitrogen (N) in agricultural soils and thus may mitigate the effects of atmospheric greenhouse gases. In this study, the effects of fertilizer... more
Fertilizer application has the potential to promote the sequestration of carbon (C) and nitrogen (N) in agricultural soils and thus may mitigate the effects of atmospheric greenhouse gases. In this study, the effects of fertilizer practices [i.e., no fertilizer (CK), chemical fertilizer (NPK), and chemical fertilizer plus low or high rates of organic manure (LOM or HOM)] on soil organic
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... Authors: Wang, Hongqing 1 ; Hladik, CM 2 ; Huang, Wenrui 3 ; Milla, K. 3 ; Edmiston, L. 4 ; Harwell, MA 5 ; Schalles, JF 3. Source: International Journal of Remote Sensing, Volume 31, Number 2, 2010 , pp. 439-453(15). Publisher:... more
... Authors: Wang, Hongqing 1 ; Hladik, CM 2 ; Huang, Wenrui 3 ; Milla, K. 3 ; Edmiston, L. 4 ; Harwell, MA 5 ; Schalles, JF 3. Source: International Journal of Remote Sensing, Volume 31, Number 2, 2010 , pp. 439-453(15). Publisher: Taylor and Francis Ltd. ...
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Research Interests: Environmental Science, Climate Change, Climate variability, Modeling, Forest Ecology And Management, and 15 moreClimate, Puerto Rico, Forest Ecology, Biological Sciences, Environmental Sciences, Light, Respiration, Climate Model, Spatial Pattern, Primary Production, Primary productivity, Altitude, Forest Products, Simulation Model, and gross Primary Production
ABSTRACT Large sediment diversions are proposed and expected to build new wetlands to alleviate the extensive wetland loss (5,000 km2) affecting coastal Louisiana during the last 78 years. Current assessment and prediction of the impacts... more
ABSTRACT Large sediment diversions are proposed and expected to build new wetlands to alleviate the extensive wetland loss (5,000 km2) affecting coastal Louisiana during the last 78 years. Current assessment and prediction of the impacts of sediment diversions have focused on the capture and dispersal of both water and sediment on the adjacent river side and the immediate outfall marsh area. However, little is known about the effects of sediment diversions on existing wetland surface elevation and vertical accretion dynamics in the receiving basin at the landscape scale. In this study, we used a spatial wetland surface elevation model developed in support of Louisiana’s 2012 Coastal Master Plan to examine such landscape-scale effects of sediment diversions. Multiple sediment diversion projects were incorporated in the model to simulate surface elevation and vertical accretion for the next 50 years (2010-2060) under two environmental (moderate and less optimistic) scenarios. Specifically, we examined landscape-scale surface elevation and vertical accretion trends under diversions with different geographical locations, diverted discharge rates, and geomorphic characteristics of the receiving basin. Model results indicate that small diversions (< 283 m3 s-1) tend to have limited effects of reducing landscape-scale elevation loss (< 3%) compared to a future without action (FWOA) condition. Large sediment diversions (> 1,500 m3 s-1) are required to achieve landscape-level benefits to promote surface elevation via vertical accretion to keep pace with rising sea level.
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Research Interests: Environmental Science, Climate Change, Puerto Rico, Multidisciplinary, Ecological Modelling, and 11 moreGlobal Warming, Tropical forest, Potential Evapotranspiration, Soil Carbon, Biomass production, Air Temperature, Soil Organic Carbon, Forest Products, Seasonal Dynamics, gross Primary Production, and Climatic condition
Research Interests: Biology, Multidisciplinary, Ecological Modelling, Food supply, Population Size, and 14 moreFood Availability, Population Model, Two-Dimensional Hydrodynamic Model, Growth rate, Statistical Model, Optimal Growth, Physical Model, Age Structure, Simulation Model, Hydrodynamic Model, Model simulation, Multivariable System, Crassostrea virginica, and Environmental factor
Remote sensing of total suspended solids (TSS) by satellite techniques in estuaries and bays plays an important role in monitoring water quality over a large area. It is valuable to the management of coastal water environment and... more
Remote sensing of total suspended solids (TSS) by satellite techniques in estuaries and bays plays an important role in monitoring water quality over a large area. It is valuable to the management of coastal water environment and ecosystems. In this study, remote sensing mapping of TSS was conducted to investigate the effects of rainstorm events on Apalachicola Bay. A rainstorm
Research Interests: Environmental Science, Computer Science, Remote Sensing, Water quality, Ecological Informatics, and 11 moreBiological Sciences, Model, Water Quality Assessment, Regression Model, Coastal waters, Water Quality, Wind Speed, Reference Value, River Discharge, Total suspended solids., and total suspended solid (TSS)
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Research Interests: Environmental Science, Climate Change, Puerto Rico, Multidisciplinary, Ecological Modelling, and 11 moreGlobal Warming, Tropical forest, Potential Evapotranspiration, Soil Carbon, Biomass production, Air Temperature, Soil Organic Carbon, Forest Products, Seasonal Dynamics, gross Primary Production, and Climatic condition
Research Interests: Landscape Ecology, Earth Sciences, Environmental Science, Spatial Statistics, Puerto Rico, and 15 moreBiological Sciences, Spatial autocorrelation, Environmental Sciences, Soil moisture, Spatial Variability, Spatial Variation, Soil Organic Carbon, Spatial Correlation, Soil Properties, Spatial structure, Bulk Density, Elevation Gradient, Spatial Dependence, Positioning System, and Abiotic factors
The eastern oyster (Crassostrea virginica) plays an important role both ecologically and economically in Apalachicola Bay, Florida. Oyster population features such as population size, age structure, spawning, growth, and reproduction are... more
The eastern oyster (Crassostrea virginica) plays an important role both ecologically and economically in Apalachicola Bay, Florida. Oyster population features such as population size, age structure, spawning, growth, and reproduction are closely related to bay salinity, which is often affected by freshwater flows from the Apalachicola River. Existing modeling approaches have used statistical models to examine the effects of changing
Research Interests: Biology, Multidisciplinary, Ecological Modelling, Food supply, Population Size, and 14 moreFood Availability, Population Model, Two-Dimensional Hydrodynamic Model, Growth rate, Statistical Model, Optimal Growth, Physical Model, Age Structure, Simulation Model, Hydrodynamic Model, Model simulation, Multivariable System, Crassostrea virginica, and Environmental factor
There are few studies that have examined the spatial variability of forest productivity over an entire tropical forested landscape. In this study, we used a spatially-explicit forest productivity model, TOPOPROD, which is based on the... more
There are few studies that have examined the spatial variability of forest productivity over an entire tropical forested landscape. In this study, we used a spatially-explicit forest productivity model, TOPOPROD, which is based on the FOREST-BGC model, to simulate spatial patterns of gross primary productivity (GPP), net primary productivity (NPP), and respiration over the entire Luquillo Experimental Forest (LEF) in the mountains of northeastern Puerto Rico. We modeled climate variables (e.g. solar insolation, temperature, rainfall and transpiration) using a topography-based climate model, TOPOCLIM. The simulated GPP ranged from 8 to 92 t C/ha per year with a mean of 51 t C/ha per year. The simulated NPP ranged from 0.5 to 24 t C/ha per year with a mean of 9.4 t C/ha per year. The simulated plant respiration ranged from 31 to 68 with a mean of 42 t C/ha per year. Simulated GPP and respiration declined with increased elevation whereas simulated NPP increased from low to middle eleva...