Thomas W. Giambelluca


Department of Geography
University of Hawai`i at Manoa

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Current Projects

Title: Hydrology of Tropical Montane Cloud Forest in Hawai‘i

PI: Thomas Giambelluca
Collaborators: Sampurno Bruijnzeel (Vrije University, Amsterdam), David Foote (USGS, BRD, Hawai‘i Volcanoes National Park), James Juvik (Geography and Environmental Studies, UH Hilo), Randy Senock (Geological and Environmental Sciences, Cal State Chico)
Funded by: National Science Foundation

Objectives: (1) Determine the rates of evapotranspiration, transpiration, interception evaporation, and soil/litter evaporation for wet forest sites in Hawai‘i; (2) Determine fog interception, interception evaporation, stem flow, stem storage, and transpiration in native forest and in an alien species stand; (3) Test alternative methods of estimating ET for Hawai’i forest sites; and (4) Use alternative methods to estimate ET at existing observing sites on Maui.

Methods: We are currently conducting comprehensive field measurements of all components of water flux into, out of, and within the vegetative layer at two forest sites on Hawai'i Island.  The two field sites are located in native forest and a forest invaded by an alien tree species, both within the cloud zone.  These sites are equipped with the full array of instruments, including eddy covariance sensors, to monitor fluxes of water and carbon between the atmosphere and the surface, and automated throughfall and stemflow gauges to measure the partitioning of rainfall and cloud water interception in the canopy.

Title: Sensitivity of Pacific Island Tropical Montane Cloud Forests to Climate Change: Observing Climatic and Hydrological Processes

PI: Thomas Giambelluca
Funded by: US Geological Survey, Biological Resources Discipline Global Change Research Program
Project is a subset of the parent project, "Sensitivity of Pacific Island Tropical Montane Cloud Forests to Climate Change”. The principal BRD contacts are Drs. Lloyd Loope and David Foote.

Objectives of the parent project: (1) Continue measurements of interannual microclimatic variability for TMCFs at Haleakala and Hawaii Volcanoes National Parks; expand the network to include a TMCF in the National Park of American Samoa (NPSA) as a representative TMCF for the southern tropical Pacific; and develop a model of cloud water interception based on surface wind velocity, liquid water content of surface air, and canopy characteristics. (2) Sample paleoecological indices of the presence of cloud forest vegetation, including chironomids, to determine past changes in climate and the height and extent of cloud forest in Hawai‘i and American Samoa. (3) Examine feedbacks between TMCF hydrology, climate change and aquatic communities to better understand the patterns of population outbreaks mosquitoes that serve as disease vectors. (4) Use information gained in the first three objectives to provide DOI land managers with guidance on restoration projects focused on TMCF sites with a long history of disturbance, including Hakalau Forest National Wildlife Refuge and the new 2003 116,000 acre Kahuku tract addition to Hawaii Volcanoes National Park.

Methods: We are currently conducting field measurements of hydrologically-sensitive canopy characteristics in forests below, within, and above the current fog zone in Hawai'i. We are also working to develop a model of cloud water interception based on surface wind velocity, liquid water content of surface air, and canopy characteristics.

Title: Hydrological Impacts of Miconia calvescens in Hawai‘i

PI: Thomas Giambelluca
Co-PIs/Collaborators: Ross Sutherland (Geography, UH Manoa), Alan Ziegler (Geography, UH Manoa), Kazuki Nanko (University of Tsukuba, Japan) , Qi Chen (Geography, UH Manoa)
Funded by: US Fish and Wildlife Service

Objectives: To identify the ecological-hydrological differences between the invasive tree species Miconia calvescens and native forest vegetation. The study is focused specifically on light extinction, effects on under-canopy drop-size distribution, and alteration in soil characteristics.

Methods: We are measuring light extinction under Miconia and non-Miconia canopies using a Sunfleck Ceptometer (Decagon, Pullman, WA, USA).  Samples of photosynthetically-active radiation (PAR) are taken beneath the canopy of Miconia and a control stand, each compared with PAR samples taken in the open, to determine the degree to which Miconia reduces light reaching the understory level. Drop size distribution (DSS) is being sampled using the laser disdrometer developed by Kazuki Nanko (Nanko et al., 2004).  The instrument uses a laser transmitter and receiver oriented to allow rain or throughfall drops to pass through the beam.  At each measurement site, a disdrometer is set up for brief periods to monitor under-canopy DSS at Miconia and control sites.  During monitoring periods, we also measure above-canopy rainfall intensity, using a tipping-bucket raingage and event logger, and above-canopy wind velocity, using a cup anemometer and data logger.  Rainfall intensity and wind velocity affect canopy vibration, which influences DSS. Drop size and velocity measurements will be used to determine the kinetic energy of drop impact on the soil and to estimate the rate of splash detachment of soil particles that results. We will use ground-based LiDAR to characterize the canopy structure at each measurement site, and to attempt to measure the amount of root exposure that has resulted from soil erosion under Miconia.

Title: Improving Water Resource Assessment in Hawai‘i by Using LiDAR Measurements of Canopy Structure to Estimate Rainfall Interception

PI: Thomas Giambelluca
Co-PI: Qi Chen (Geography, UH Manoa)
Funded by: U.S. Geological Survey, Water Resources Research Institute Program

Objectives: To utilize a ground-based LiDAR system and existing state-of-the-art field measurement facilities to develop and test a new method for estimating interception in Hawai‘i’s native and invaded forests. 

Methods: We will use a ground-based LiDAR system to map the 3-dimensional above-ground biomass distribution at two existing study sites within Hawai‘i Volcanoes National Park.  The two sites represent intact native M. polymorpha forest and a P. cattleianum-dominated invaded forest.  At each site we are already operating a flux tower fully equipped with eddy-covariance, micro­meteoro­logical, and canopy water balance sensor systems.  The LiDAR data will be used to determine the following canopy structural parameters: canopy gap fraction, tree density, leaf area index, tree height, lower crown limit, basal area, canopy bio­mass, canopy area index, stem diameter, branch diameter, and branch inclination angle.  This information is needed to set parameter values (canopy capacity, canopy cover fraction, trunk storage capacity, free throughfall coefficient, and fraction of water diverted to stemflow) in the Gash (1995) revised analytical interception model (Table 1).  We will use the model to estimate TF, SF, and I, and compare the results against our measurements of TF and SF at each site.

Title: The Expansion of Rubber and Its Implications for Water and Carbon Dynamics in Montane Mainland Southeast Asia

PI: Jeff Fox (East-West Center)
Co-PI and Institutional PI: Thomas Giambelluca
Other Co-PIs: Qi Chen (Geography, UH Manoa), Alan Ziegler (Geography, UH Manoa)
Funded by: National Aeronautics and Space Administration

Objectives: The overarching science question to be addressed by this proposal is: How does the conversion from existing land covers to rubber affect local energy, water, and carbon fluxes, how extensive will rubber become in MMSEA, and what are the consequences of those changes for regional hydrology and carbon sequestration?  Specific science questions are: (1) Where is rubber being planted in the region and what are current and predicted patterns of this expansion in relation to other land-cover types? (2) How do factors influencing the adoption and location of rubber vary across MMSEA and how will these differences affect predicted patterns and rates of expansion in the region? (3) What are the ecophysiological characteristics of rubber and how do they differ from the vegetation that rubber is replacing in MMSEA? (4) What are the diurnal, seasonal, and interannual patterns in energy exchange, evapotranspiration, net ecosystem exchange of carbon, and aboveground net primary productivity for rubber and the principal vegetation types being replaced by rubber? (5) How does the unique phenological behavior of rubber influence the timing and rates of water flows through affected watersheds and carbon exchange and sequestration? (6) What are the historical spatial and temporal patterns of carbon sources and sinks over MMSEA? (7) How will the expansion of rubber and related land-use change alter the region-wide storage of carbon? (8) How will climate change interact with rubber-related land-cover/land-use change (LCLUC) to alter the regional stocks and fluxes of carbon and water over the next 50 years?

Methods: To characterize the recent and current extent of rubber in MMSEA, we will develop land-cover/land-use time-series maps for emerging, rubber-growing sites in MMSEA using knowledge-based classification and visual interpretation of multi-sensor, multi-date remotely sensed imagery with a focus on identifying rubber cultivation as a distinct land use among forests, grasslands and other types of agriculture. Expansion of rubber to 2050 will be simulated by combining a regional suitability model for rubber with a dynamic, spatially-explicit, land cover/use change (LCLUC) model. We will use eddy covariance to measure water and carbon fluxes over rubber and secondary vegetation. The Ecosystem Demography model, parameterized by satellite spectral and LiDAR data, and observations of stand characteristics, including ground-based LiDAR, and calibrated by flux measurements, will be used to develop spatially-distributed estimates of water and carbon fluxes throughout MMSEA. This proposal is directly responsive to the goals stated in the NRA "to further understanding of the consequences of LCLUC on the carbon and water cycles.” 

Title: A Climate Impacts Based Assessment of Climate Change Projections in the Hawaiian Islands Region (HIR)

PI: Henry Diaz (NOAA)
Co-PIs: Oliver Timm (IPRC, UH Manoa), Thomas Giambelluca, Kevin Hamilton (IPRC, UH Manoa)
Funded by: US Geological Survey, Biological Resources Discipline

Objectives: To develop estimates of how the statistical properties of key characteristics of Hawaiian Islands Region climate will have changed by the end of the 21st century.

Methods: To address the project objectives, we will (1) compare model climatology with observations; (2) analyze the most robust large-scale climate patterns and inferences about future climate states; (3) validate the important features of the seasonal climate cycle in HIR; (4) validate the important interannual and decadal features of climatic variability in HIR; and (5) develop appropriate analysis tools including nested regional dynamical models for describing HIR-relevant climate changes in a selected suite of climate model simulations from the IPCC AR4.

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Some Prior Projects



  • WATER RESOURCES: Evapotranspiration on Tutuila, American Samoa



  • HYDRAULIC LIFT: Water Economy of Neo-tropical Savana Ecosystems


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Contact Information

Email: thomas (at)
Office phone: 808 956 7390
FAX number: 808 956 3512
Mailing address:
Department of Geography
University of Hawai`i at Manoa
2424 Maile Way Honolulu
Hawai`i 96822 USA


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Copyright: Thomas W. Giambelluca
Last revised: 31 May 2008