water stream over rocks


THOMAS GIAMBELLUCADirector, WRRC; Professor, Department of Geography and Environment

Office: Holmes Hall 283
Phone: (808) 956-7848
Fax: (808) 956-5044
E-mail: thomas@hawaii.edu

THOMAS GIAMBELLUCADirector, WRRC; Professor, Department of Geography and Environment


PHONE: (808) 956-7848
FAX: (808) 956-5044



  • PhD, Geography, University of Hawaiʻi at Mānoa, 1983
  • MA, Geography, University of Miami, 1977
  • BS (cum laude), Geography and Mathematics, University of Miami, Florida, 1974


The foci of my research are (1) climate variability, both spatial and over time, including natural fluctuation and trends associated with global climate change, and looking at both past changes and projections of future changes; and (2) interaction between the atmosphere and the land surface, including effects of land cover change on exchanges of water, carbon, and energy over terrestrial ecosystems, effects of invasive plants on ecosystem function, and hydrological processes in tropical montane cloud forests.

Tom Giambelluca 2021–2022 Publications



Evaluation of Climate Monitoring on Mauna Kea

University management boundaries and areas surrounding Maunakea. Blue dots indicate existing weather stations including rain gages. Red dots indicate possible sites for new stations.
In this project we are planning and working to gain the acceptance and participation from relevant stakeholders for future deployment of instrumentation to continuously monitor the climate of the upper elevations of Mauna Kea

Trends In Hawaiian Rainfall: Detection and Attribution Studies Using CMIP6 DAMIP Multi-Model Ensemble

This research allows us to determine to what degree the apparent trends (mostly downward) in Hawai‘i rainfall can be attributed to the effects of global climate changes as opposed to natural variabilities. This outcome will be extremely valuable as a guide to interpreting projections of future changes.

Transpiration Characteristics of Native and Non-Native Plants at a Leeward Ko‘olau Forest Site, O‘ahu, Hawai‘i

Maximum wet season sap velocities (a–c) and whole-tree sap flux (d–f) for multiple individuals of each species, plotted against diameter at breast height, for the Nov 2018-March 2019 study period (left column), five sunny days with higher soil moisture (center column), and c) five sunny days with lower soil moisture (right column). Mean diurnal sap velocities for each species for all days (g), sunny with high soil moisture (h), and sunny with lower soil moisture (i).
Controlling or eradicating non-native plants in Hawai‘i is difficult and expensive. Knowledge of the impacts of non-native plants on water resources is important for water managers and conservation organizations to help them plan for the best use of their resources to restore and maintain the hydrological function of Hawai‘i’s watersheds.

Development of a Pilot Scale Water Resources Research Center Outputs and Products Data Portal

The primary goal for this proposed work is to develop an open data portal to archive and provide access to research products developed through efforts of UH WRRC and ASCCLG. The portal will improve the searchability for publications, reports, and data.

Evaluating Similarities and Differences Between Statistical and Dynamical Downscaling Projections

A boxplot showing the range of estimates per year given the set of competing models for a) wet season and b) dry season for Hilo station. The blue solid line represents the actual seasonal rainfall at Hilo station for each year and the red dotted line represents the estimate from the Elison Timm et al. (2015) model.
Activities in this project fall under four core objectives: (1) conduct place-based assessment of risk, vulnerabilities, and adaptation strategies; (2) support implementation of these strategies; (3) evaluate adaptation plans and policy throughout the region; and (4) integrate technical climate information and policy outcomes.

Cloud Water Interception in Hawai‘i

Cloud water interception field research sites.
This study obtained data to develop a model to simulate the spatial patterns of cloud water interception (CWI) in Hawai‘i, sensors and canopy water balance systems were deployed at five sites. Three of the sites used tensiometers to estimate the spatial and temporal variability of recharge rates associated with CWI.

Development of Digital Meteorological Surfaces for Modeling of Hydrological Processes in Hawai‘i

Figure 1. Sample digital monthly rainfall map (December 2019) automatically produced in near real time from telemetered raingage data.
This project is developing a system to automatically produce near-real-time climate map products, beginning with monthly and daily rainfall, at high spatial resolution.

Projecting Near-Term Climate Variability and Change of the Main Hawaiian Islands to Provide Actionable Climate Information to Resource Managers and Decision Makers

Figure 1. Wet (left) and dry (right) season rainfall differences (mm per day) from the historical mean simulation. Stippling indicates statistical significance at the 5% significance level obtained with Monte-Carlo resampling. Panels a – d show the differences between future (Fut) and present day (Pres) climate under warm PDO (+) and cold PDO (-) phases. Panels e – h present the differences between PDO phases under present-day and future climate conditions.
This study measures fog, wind, fog interception, changes in plant water use because of fog, and the amount of water added to the hydrological cycle by fog. The data is used to test a model to estimate cloud water interception (CWI) as a function of fog-water movement and vegetation type.

Improving Water Resource Assessment in Hawaii by Using LiDAR Measurements of Canopy Structure to Estimate Rainfall Interception

SPONSOR: National Institute for Water Resources, Water Resources Research Institute Program PROJECT PERIOD: 03/01/08 – 02/28/09 ABSTRACT: Water resources in Hawaii continue to experience increasing demand, putting pressure on existing sources and increasing the need for better estimates of resource…

Monthly Rainfall Maps for the Islands of Kauai, Oahu, Molokai, Maui, and Hawaii, 2008-2010

SPONSOR: National Institute for Water Resources, Water Resources Research Institute Program PROJECT PERIOD: 03/01/2013-02/28/2014 ABSTRACT: The Hawaiian Islands have one of the most diverse rainfall patterns on Earth. The mountainous terrain, the persistent trade winds, the heating and cooling of…