Weather in Economic Models: From Supply and Demand to Climate Impacts

Presented on April 9, 2025, by

Michael J. Roberts, Professor
Economics, Sea Grant, UHERO
University of Hawai’i Mānoa

ABSTRACT:

In this talk, I’ll give an informal overview of research projects that integrate high-resolution weather data into economic analysis. Topics will span several domains, including the effects of climate change on agriculture, empirical models of food supply and demand, and the role of weather in renewable energy integration—highlighting transmission, demand response, and natural gas infrastructure planning. I’ll also touch on how climate change may shift natural gas demand. Looking ahead, I’ll discuss emerging opportunities at the intersection of economics, artificial intelligence, and forecasting—especially for weather, crop yields, and renewable energy—and how improved forecasting could enhance the performance of food and energy markets, as well as the design of weather index insurance.

Spatial Matters! The Role of Rainfall in Flash Floods on Small Mountainous Watersheds

Presented on April 2, 2025, by

Dr. Yu-Fen Huang
Junior Researcher
Tsang Stream Lab
Department of Natural Resources and Environmental Management (NREM)
University of Hawaiʻi at Mānoa

ABSTRACT: 

Flash floods pose significant risks in mountainous watersheds due to the rapid streamflow response to rainfall. This presentation explores the role of rainfall spatial structure in shaping hydrological responses in small watersheds (< 40 km²) on Oʻahu. We investigated how specific rainfall characteristics beyond rainfall amount and intensity—including rainfall area, connectivity of rainfall clusters, and spatial dispersion—affect high-flow events. Using the WRF-Hydro® model with high-resolution rainfall data and the Random Balance Designs – Fourier Amplitude Sensitivity Testing (RBD-FAST) method, we analyzed rainfall-streamflow relationships across seven watersheds on Oʻahu, Hawai‘i, from 2015 to 2020. Key findings highlight that heavy rainfall areas (≥25 mm/hr), rainfall cluster connectivity, and dispersive indices significantly influence peak flow magnitude. Additionally, small shifts in rainfall location notably impact peak flow, underscoring the importance of precise rainfall spatial data. Our results emphasize the need to incorporate rainfall spatial structure and its associated uncertainties into flood prediction models to improve streamflow forecasting and flood risk assessment.  

Aerosol dispersion and settling in the turbulent boundary layer

Presented on March 12, 2025, by

Dr. David Richter
Department of Civil and Environmental Engineering and Earth Sciences
University of Notre Dame

ABSTRACT:

In the marine and terrestrial boundary layers, aerosol particles are continually being produced, transported, and deposited, and these particles play a central role in multiple atmospheric processes including chemistry and cloud microphysics. These particles range from the nanometer to millimeter scale in size, and are subject to different physics based on their origin, composition, and size. As such, it is important to understand their transport throughout the atmospheric boundary layer, since this ultimately dictates their lifetime and relative abundance. The problem, however, is in fully accounting for this particle dispersion, and gaps in our understanding have taken many forms over the decades. For example, relating measured airborne concentrations to local generation rates makes assumptions about particle deposition rates and locality in transport, neither of which has been fully verified. In this presentation, I will provide an overview of our group’s efforts at trying to understand the relevant mechanisms controlling transport, especially for large (i.e., potentially inertial) particles in the boundary layer. Our primary tool is turbulence-resolving large-eddy simulations, where particles are tracked in a Lagrangian frame. We have found that insufficient sampling strategies can lead to highly incorrect surface emission estimates, and that particle inertia can violate traditional deposition models. These and other key findings will be discussed.

The Climate Data Lifecycle: From Measurement to Dissemination

Presented on February 26, 2025, by

Ryan Longman, PhD
University Consortium Program Director
Pacific Islands Climate Adaptation Science Center (PICASC)
Sea Grant College Program, University of Hawaii at Mānoa

ABSTRACT:

Climate data and information are foundational to resource management, decision-making, and planning. The climate data lifecycle begins with measurements and culminates in the delivery of high-quality data to those who need it most. This presentation will explore the key components of the climate data lifecycle in Hawaii, drawing from published research and ongoing initiatives aimed at improving our ability to measure environmental phenomena and produce valuable data products. We will also examine the 36-year history of climate mapping in Hawaii and how it has paved the way for the development of the Hawaii Mesonet, Hawaii Climate Data Portal (HCDP), and the Pacific Drought Knowledge Exchange (PDKE) projects, all of which are fulfilling critical data needs in the State.

Atmospheric modeling over complex terrain: mesoscale modeling, large-eddy simulation, and the gray zone

Presented on February 12, 2025, by

Professor Tina Katopodes Chow
Civil and Environmental Engineering
UC Berkeley

ABSTRACT


This talk describes the challenges posed by taking mesoscale numerical models to finer 

and finer resolutions, as is becoming increasingly common in atmospheric modeling over complex terrain. At the mesoscale, planetary boundary layer  parameterizations are used to represent turbulence; at the microscale, large-eddy simulation (LES) closures are used. The “gray zone” is the range of grid  resolutions in between classic mesoscale and classic LES resolutions where particular features are neither subgrid nor fully resolved but rather are partially  resolved. The definition of the gray zone depends strongly on the feature being represented and its relationship to the model resolution. We will address  challenges in the gray zone and describe best practices for choosing the turbulence closure model and setting up grid nesting, with multiple examples of simulations over complex terrain.
BIO

Tina’s research group aims to improve the numerical models used for weather prediction and air quality forecasts. She and her students have worked on  predicting how wind turbines respond in turbulent flow, how wildfire smoke spreads, where pollution is distributed in an urban environment, and how winds are  affected by complex mountainous terrain, among other applications. Tina received a B.S. in Engineering Sciences from Harvard University and M.S. and Ph.D.  degrees in Civil and Environmental Engineering from Stanford University. She has been a professor in Civil and Environmental Engineering at the University of  California, Berkeley, since 2005, where she teaches fluid mechanics, numerical modeling, and community-engaged design courses.

Exploring Climate Tipping Points and Surface Temperature Projections through Advanced Modeling

Presented on January 22, 2025, by

Dr. Jonathan H. Jiang
Senior Research Scientist
Jet Propulsion Laboratory
California Institute of Technology

ABSTRACT

This seminar will explore climate tipping points and the conditions under which global temperature changes become irreversible, utilizing advanced atmosphere-ocean-ice coupled models. Building on preliminary findings, our study highlights the threshold where surface temperature increases may become irreversible beyond 2-3°C above pre-industrial levels and examines other critical tipping elements like AMOC collapse and Greenland ice sheet loss. Additionally, we analyze global and regional surface temperature trends, focusing on the Arctic’s rapid warming, using CMIP6 models to project when critical temperature thresholds (1.5, 2.0, 2.5°C) will be reached. The seminar aims to inform climate science and policy, equipping policymakers with insights to avert catastrophic climate impacts.

BIO

Dr. Jonathan H. Jiang is a Senior Research Scientist at the Jet Propulsion Laboratory, California Institute of Technology, with over two decades of experience leading pioneering research in satellite remote sensing, climate science, astrophysics, and the search for extraterrestrial intelligence. Dr. Jiang serves as the president of the American Geophysical Union (AGU) Global Environmental Change section and editor-in-chief of AGU’s Earth and Space Science Open Archive. A recipient of three NASA Medals for Exceptional Scientific Achievement and a Fellow of the American Meteorological Society, Dr. Jiang is also a member of the National Academy of Sciences, Engineering, and Medicine’s Committee on Human Exploration of Mars.

Reexamination of the moisture-vortex and baroclinic instabilities in the South Asian summer monsoon

Presented on November 13, 2024, by

Professor Tim Li
Department of Atmospheric Sciences
University of Hawaii

ABSTRACT

Energetic synoptic-scale disturbances often develop over the South Asian Monsoon region, but mechanisms responsible for the observed phenomenon remains open. Given a strong easterly vertical shear of the background mean flow, a possible candidate is baroclinic instability (BI), but this mechanism was denied by Cohen and Boos (2016) based on the observed vertical structure of the monsoon depressions. Another candidate is the moisture-vortex instability (MVI) proposed by Adames (2021) in which perturbation moisture caused by anomalous meridional and zonal advection holds a key for eddy available potential energy generation.

In this work we re-examine the BI and MVI, by examining the characteristics of general synoptic disturbances and conducting a theoretical study with a 2.5-layer model that extends the classic 2-level quasi-geostrophic model to including a prognostic lower-tropospheric moisture tendency equation and an interactive planetary boundary layer. It is found that the BI does work in the South Asian monsoon, and that the most unstable mode prefers a zonal wavelength of 4000 km, a westward phase speed of 6 m s -1 , an eastward tilt vertical structure and a westward shift of maximum moisture and precipitation centers relative to the lower-tropospheric vorticity center, all of which agree with the observations. Sensitivity experiments show that low-level westerly is not a necessary condition for the MVI to occur and the growth rate is reversely proportional to convective adjustment time, both of which contradict to Adames (2021). Thus, the current work sheds light on understanding the fundamental dynamics of the South Asian monsoon.

A climate change signal in the tropical Pacific emerges from decadal variability

Presented on Wednesday, November 6, 2024, by

Feng Jiang, Ph.D. 
Research Scientist 
Lamont-Doherty Earth Observatory
Columbia University

ABSTRACT

Why has the tropical eastern Pacific cooled—or at least resisted warming—over the past several decades? This divergence from the general expectation of warming in response to rising greenhouse gases is fascinating in its own right. Adding to the mystery is that generations of climate models have consistently simulated the opposite: a warmer cold tongue region. Recent debates have centered around whether this lack of warming in the cold tongue is a response to anthropogenic forcings or internal variability, particularly the Interdecadal Pacific Oscillation (IPO). Here we identify an emerging climate change signal in the tropical Pacific that we call the Pacific Climate Change (PCC) pattern. This is clearly distinguishable from the decadal variability of the IPO. While the IPO is associated with a meridionally broad, wedge-shaped sea surface temperature (SST) anomaly, the PCC features a narrow band of cooling along the equator with warming elsewhere. The PCC emerges over time while the IPO oscillates back and forth as expected if the PCC is a signal of climate change and the IPO is natural variability. Both the PCC and IPO involve changes in thermocline depth and subsurface temperature in the upwelling regions of the central to eastern equatorial Pacific. Despite this similarity we show, using ocean data and a simple wind-driven ocean model, that the PCC’s atmosphere-ocean dynamics are fundamentally different from those of the IPO. On this basis, we discuss potential reasons for coupled climate models to misrepresent the upper ocean’s response to anthropogenic forcing that compromise the reliability of past simulations and projections of the tropical Pacific and beyond.

BIO

Feng Jiang received her Ph.D. from the Nanjing University of Information Science and Technology, where she was supervised by Wenjun Zhang and co-advised by Fei-Fei Jin. Her doctoral research focused on tropical inter-basin interactions among the Pacific, Atlantic, and Indian Oceans on interannual timescales. She is currently a postdoctoral research scientist at Lamont-Doherty Earth Observatory, Columbia University, collaborating with Richard Seager and Mark Cane to understand the response of the upper tropical Pacific Ocean to radiative forcing.

NSF Engineering Research Center EARTH: An information session

Presented on Wednesday, October 30, 2024, by

The University of Hawaii ERC EARTH Team

The University of Hawaii at Manoa is part of a team of six universities (UHM, Notre Dame, Lehigh University, University of South Dakota, and University of Maryland, and ERC lead University of Kansas) awarded $26 million to establish EARTH (Environmentally Applied Refrigerant Technology Hub), one of four new NSF Gen-4 Engineering Research Centers (ERC) announced in August 2024. EARTH will create a transformative, sustainable refrigerant lifecycle to reduce global warming from refrigerants while increasing the energy efficiency of heating, ventilation, and cooling.

The replacement of chlorofluorocarbons (CFCs) and the subsequent recovery of the ozone layer following the Montreal Protocol is hailed as the most significant environmental success story in recent history. The phase-out of hydrofluorocarbons (HFCs) and the adoption of more energy-efficient cooling technologies in accordance with the Kigali Amendment, F-gas regulations, and the AIM Act will represent the next big environmental success story for the global community.

The UH team’s contributions to ERC EARTH are diverse and interdisciplinary: from climate modeling (Prof. Karamperidou) to experimental and computational atmospheric chemistry (Prof. R. Kaiser, and Prof. R. Sun) and environmental history (Prof. K. Matteson) to key leadership roles in EARTH’s Diversity and Culture of Inclusion effort (J. Pagala Barnett) and the Student Leadership Council (Chemistry PhD student A. Vincent).

In this information session, kicked off by EARTH Director Mark Shiflett, the UH EARTH team will provide an overview of the project and introduce some of the research elements involved, along with information on open positions and student projects, and partnerships across the ERC EARTH institutions. For more information, please visit the EARTH webpage at https://erc-earth.ku.edu/

Double Feature: Building Planets, Using General Circulation Models to Understand Extreme Weather and Large-Scale Dynamics in a Changing Climate // Actual Actions to Address Underrepresentation in Climate Science

Presented on October 9, 2024, by

Veeshan “Vee” Narinesingh, Ph.D. 
Physical Scientist, Atmospheric Physics Division
NOAA Geophysical Fluid Dynamics Laboratory (GFDL)Chair, GFDL Diversity, Equity, Inclusion, & Accessibility Committee (DEIAC) 

ABSTRACT:

General Circulation Models (GCMs) are some of humankind’s best tools for understanding earth’s climate in the past, present, and possible futures. In this talk we will discuss applications of GCMs to understand the behavior and proliferation of atmospheric blocking (persistent anticyclones) and extreme heat events in current and future possible climates. This will include the use of idealized model simulations modifying orography and sea surface temperature, up through fully coupled, comprehensive GCMs.

We will also discuss initiatives that GFDL is leading to increase the participation of diverse scientists and communities in climate science research.  

BIO:

Dr. Veeshan “Vee” Narinesingh (he/him/his) is a New York raised, Trinidadian American physicist at NOAA Geophysical Fluid Dynamics Laboratory (GFDL). He specializes in large-scale atmospheric dynamics and weather extremes, in addition to the advancement of diversity, equity, inclusion, and accessibility (DEIA) in science. 50% of his job is dedicated to scientific research and 50% to DEIA. Vee completed his postdoctoral work at NOAA GFDL and Princeton University’s Cooperative Institute for Modeling the Earth System (CIMES), and his Ph.D. and B.S. in Physics at The City University of New York (CUNY). He also has an expansive background in DEIA, creating and leading many initiatives over the years for both the public and private sectors.