Dr. Kelly Núñez Ocasio, an assistant professor in Texas A&M University's Department of Atmospheric Sciences, is advancing tropical climate research through a novel approach to studying weather systems. Her recent collaborative study with Dr. Erin Dougherty from the National Center for Atmospheric Research (NCAR) employs kilometer-scale modeling to assess how climate change is likely to alter weather patterns in Africa and the Atlantic. The research highlights significant shifts in rainfall and wind patterns, particularly the Intertropical Convergence Zone (ITCZ) and West African monsoon (WAM) systems.
The ITCZ, where trade winds converge near the equator, is a key driver of global weather patterns and precipitation cycles. Similarly, the WAM drives African rainfall and supports the development of African easterly waves, which are the precursors to many Atlantic hurricanes. Developing accurate models of this region is crucial for forecasting extreme weather events, such as hurricanes and heavy rains, which affect millions of people every year. By refining these models, this research improves weather forecasts, enhances disaster preparedness, and offers policymakers valuable insights for addressing climate change challenges.
"This study will lay the groundwork for my research group at Texas A&M," said Núñez Ocasio. "Dr. Dougherty and I have already submitted a proposal to the National Science Foundation (NSF) to build on this work."
Enhancing Weather and Climate Modeling
Núñez Ocasio's research utilized the Model for Prediction Across Scales (MPAS) to simulate weather systems over Africa and the Atlantic at an extraordinary resolution of three kilometers. This novel storm-resolving high-resolution regional approach eliminates the reliance on traditional methods for simulating convective storms, resulting in more precise predictions of small-scale weather patterns, facilitating more accurate forecasts.
"We discovered that the African easterly jet, the main energy source of hurricane precursors, is strengthening but moving closer to the Sahara, resulting in delays in hurricane formation."
Additionally, the study utilized the pseudo-global warming (PGW) method, which modifies weather conditions to mirror future climate scenarios. This integration of MPAS and PGW represents the first study of its kind, marking a significant leap forward in regional climate and weather modeling and of future climate projections.
Key Findings and Real-World Implications
The research uncovered considerable changes in weather patterns due to the warming climate with potentially widespread consequences. It indicated that storms are expected to intensify, with increased rainfall during the West African monsoon, particularly in mountainous regions, while shifting slightly southward in other areas, thereby affecting water availability and agriculture.
"We discovered that the African easterly jet, the main energy source of hurricane precursors, is strengthening but moving closer to the Sahara, resulting in delays in hurricane formation," said Núñez Ocasio.
These changes may lead to increased rainfall in specific areas, raising the risks of flooding. Communities reliant on predictable seasonal rains for water-fed crops might encounter new challenges as weather patterns shift, underscoring the need for improved adaptation strategies. The study's outcomes resonate with trends observed during the 2024 Atlantic hurricane season, characterized by a robust West African monsoon and an intensified African easterly jet, which contributed to extreme rainfall across Africa and delayed the formation of tropical cyclones in the Atlantic.
"Africa produces a minimal amount of global greenhouse gas emissions yet faces significant consequences from climate change," Núñez Ocasio said. "Understanding these impacts is crucial for effective planning and adaptation efforts."
Looking Ahead
Núñez Ocasio aims to broaden her research by simulating entire seasons to provide a deeper understanding of potential changes in tropical weather systems and communicating the potential consequences to vulnerable communities over Africa, the Caribbean and eastern U.S. Her NSF proposal submission seeks to further explore seasonal trends through her innovative advanced modeling.
This research originated during her postdoctoral fellowship at NCAR and was completed at Texas A&M with support from the NSF and NCAR, alongside high-performance computing resources provided by Derecho, a state-of-the-art supercomputer, through NCAR's Computational and Information Systems Laboratory. Núñez Ocasio presented her findings at AGU2024, the annual conference of the American Geophysical Union, in Washington, D.C.