UH Researchers Aim to Improve Pacific Island Weather Forecasts

University of Hawaiʻi Mānoa professor H. Annamalai is leading a project to improve weather forecasts for US-affiliated Pacific Islands like the state of Hawaiʻi. The project is overseen by the International Pacific Research Center (IPRC) at UH Mānoa and received a $508,000 grant from the NOAA Research Modeling, Analysis, Predictions and Projections (MAPP) Program. During their research, Annamalai and his team will develop tools to pinpoint where and how errors begin to help scientists improve climate models for more reliable weather forecasts.

According to Annamalai, the US-affiliated Pacific Islands are subject to variable weather and climate. One the dominant weather influencers in the region is the El Niño-Southern Oscillation (ENSO), an alternating pattern of unusually warm and cool ocean temperatures in the tropical Pacific. ENSO can cause drought-like conditions in the southwest Pacific for 3–4 seasons of a year, as well as frequent cyclones and storms.

Annamalai said that US-affiliated leadership needs accurate predictions from climate models due to these extreme patterns. His project aims to detect modeling errors to improve the accuracy of forecasts.

“Identifying and improving processes in climate models that lead to reliable forecasts of droughts and tropical storms well in advance will allow policy makers ample time to plan and mitigate situations during extreme events,” Annamalai said. “These events have significant impacts on water resources and agriculture, defense-related operations, forest fires, air traffic and more.”

In addition, Annamalai said that the tools developed from the project will help climate modelers determine why their models are not performing well.

“Our diagnostics will be user accessible, flexible and adaptable such that they can be transitioned to any group of evaluations during model development,” Annamalai said. Annamalaiʻs research will build on results from his MAPP-funded project that is ending this year. That project focused on understanding processes that shape unusual ENSO-related precipitation during the winter season.

He and his team found that model errors in predicting unusual precipitation are strongly tied to the models’ ability to represent how moisture spreads in a certain part of the atmosphere. The project also studied how the interaction between sunlight and clouds are represented in these models. The new project will address those model errors in representing moisture, clouds, and their interaction with sunlight in the atmosphere.

One specific goal of the project is to provide set of metrics to help scientists calculate how accurately their models represent ENSO-related impacts. The project also hopes to help scientists identify sources of model errors to help inform model improvement decisions.

Other researchers a part of the project include Yi Ming, head of the Atmospheric Physics and Climate Group at NOAA‘s Geophysical Fluid Dynamics Laboratory; Richard Neale, project scientist at the National Center for Atmospheric Research; and Gill Martin, science manager at the United Kingdom Met Office, Hadley Center.

More information on the project can be found by contacting Rachel Lentz the Outreach Specialist at the International Pacific Research Center at (808) 956-2415 or Senior Researcher H. Annamalai at (808) 956-5646.