About

Dr. Jin-Yi Yu is a Professor of Earth System Science at the University of California, Irvine. He received his B.S. from National Taiwan University, his Ph.D. from the University of Washington, and conducted postdoctoral research at the University of California, Los Angeles. Dr. Yu is an expert in climate modeling, dynamics, and diagnosis, with research spanning global-scale climate changes to regional-scale variations in monsoons. He is renowned for his contributions to understanding El Nino diversity and complexity, as well as inter-basin interactions among the Pacific, Atlantic, and Indian Oceans. Notably, he discovered a new type of El Nino, termed the "Central Pacific El Nino," which has been widely accepted in the scientific community. Additionally, he proposed a wave-mean flow interaction theory explaining the north-south oscillation of the jet stream in the atmosphere, now known as the Arctic Oscillation or the Annular Mode. Dr. Yu has received several awards and honors, including the Advances in Atmospheric Sciences Outstanding Editor Award, the American Geophysical Union Editors' Citation for Excellence, and recognition in the Thomson Reuters list of the world's top 1000 climate scientists. He is a Fellow of the Meteorology Society of Taiwan. Beyond his research, Dr. Yu is dedicated to teaching and was honored with the Teaching Contribution Award by the School of Physical Sciences at the University of California, Irvine. He has also served as the Vice Chair of the Department of Earth System Science.

Research topics

• Geology
• Climatology
• Atmospheric sciences
• Environmental science
• Earth science
• Physics
• Geography
• Oceanography
• Ecology
• Biology

Selected publications

• Multi-year La Niñas Break the Interannual Symmetric GMST Responses to Strong ENSO Events

  2026-03-13

  articleOpen accessCorresponding

  Strong El Niño and La Niña events typically produce symmetric impacts on global mean surface temperature (GMST), inducing notable warming or cooling, respectively, from their developing year through the boreal summer of the following year. However, this symmetry in GMST response breaks down in the subsequent autumn and winter, and the underlying mechanism has remained unclear. This study reveals that the opposite transition behaviors of strong ENSOs are key to this breakdown: while strong El Niños commonly transition into La Niña, strong La Niñas more often persist into multi-year episodes, resulting in asymmetric climate trajectories. These divergent evolutions produce asymmetric GMST anomalies since post-summer, including not only the divergent locations and intensities of cold sea surface temperature over tropical Pacific, but also the contrasting land surface temperature dipoles over the Northern Hemisphere’s mid-to-high latitudes, mediated by tropical–extratropical teleconnections. These findings highlight a previously underappreciated source of GMST variability and offer new insight into its predictability on interannual–biennial timescales.

  PublisherDOI

• Intermodel Spread in Indian Ocean Basin Mode Simulation: Roles of Indian Ocean Winds and Pacific Cold Tongue

  Journal of Climate · 2026-03-27

  article

  Abstract The Indian Ocean basin mode (IOBM) is a major component of interannual sea surface temperature (SST) variability in the tropical Indian Ocean and acts as an atmospheric–oceanic bridge extending El Niño–Southern Oscillation (ENSO)’s climate influence into the boreal summer of its decay phase—known as the capacitor effect. Despite advancements, state-of-the-art climate models continue to show systematic biases in simulating the IOBM during ENSO decay summers. Analyzing historical simulations from 56 models in the Coupled Model Intercomparison Project phases 5 and 6 (CMIP5/6), this study identifies two dominant modes of intermodel spread in IOBM simulations: an Indian Ocean dipole (IOD)-like mode linked to climatological easterly wind biases over the equatorial Indian Ocean and an eastern Indian Ocean (EIO)-centered mode associated with equatorial Pacific cold tongue biases. The IOD-like spread pattern arises from easterly wind biases that weaken SST–thermocline coupling in the southwestern Indian Ocean, suppressing IOBM amplitude. The EIO-centered pattern stems from cold tongue biases that shift ENSO anomalies westward, altering EIO SSTs through Indo-Pacific interactions. Using statistical relationships between the spread modes and historical mean-state biases, we refine CMIP5/6 projections of the IOBM and its capacitor effect under warming, revealing a stronger and more consistent enhancement than previously estimated. These findings highlight the role of background climatological wind and SST biases in shaping model spread and underscore the importance of improving Indo-Pacific mean-state simulations for more reliable IOBM representation and future climate projections. Significance Statement This study investigates why climate models struggle to simulate the Indian Ocean basin mode (IOBM), a key feature that helps extend El Niño’s climate influence into the summer following its peak. Analyzing historical simulations from 56 models in the Coupled Model Intercomparison Project phases 5 and 6 (CMIP5/6), we identify two main sources of model disagreement: biases in tropical Indian Ocean winds and Pacific cold tongue sea surface temperatures. These mean-state biases not only distort the simulated IOBM but also weaken projections of the “capacitor effect,” in which the IOBM enables the Indian Ocean to relay El Niño’s influence. By correcting for these biases, we find that future IOBM responses and associated climate impacts may be stronger than previously thought, highlighting the need to reduce background biases in climate models.

  PublisherDOI

• ENSO’s changing grip on Bering Sea ice: The emerging control of the North Pacific meridional mode

  Science Advances · 2025-11-19 · 3 citations

  articleOpen access

  Bering Sea winter sea ice (BSWI), vital for regional climate, ecosystem, and livelihoods, is significantly influenced by El Niño-Southern Oscillation (ENSO). Here, we identify a shift in the ENSO-BSWI relationship. Pre-mid-1990s, traditional eastern Pacific ENSO dominated, driving a positive ENSO-BSWI linkage; post-mid-1990s, more frequent central Pacific (CP) ENSO events reversed this relationship to negative. Observations and model experiments show that CP El Niño coupled with positive-phase North Pacific meridional mode (NPMM) redirects poleward-propagating Rossby wave trains, enhancing Bering Sea southerlies. This suppresses ice advection, intensifies warm air intrusion, and reduces BSWI. Strengthened CP ENSO-NPMM coupling and heightened NPMM variability amplify this teleconnection, increasing its influence on BSWI by 38.9% versus NPMM alone. Our findings underscore the growing role of subtropical and tropical Pacific climate interactions in subarctic sea ice variability and highlight the need for improved climate models that capture ENSO diversity, NPMM dynamics, and subtropical-subarctic teleconnections to enhance BSWI projections under climate change.

  PublisherDOI

• Diverse NPMM conditions deviate the 2023/24 El Niño from the 1997/1998 and 2015/2016 extreme El Niño events

  npj Climate and Atmospheric Science · 2025-03-31 · 5 citations

  articleOpen accessSenior author

  Abstract The 2023/24 El Niño commenced with an exceptionally large warm water volume in the equatorial western Pacific, comparable to the extreme 1997/98 and 2015/16 events, but did not develop into a super El Niño. This study highlights the critical role of contrasting Northern Pacific Meridional Mode (NPMM) conditions in this divergence. Warm NPMM conditions during the 1997/98 and 2015/16 events created a positive zonal sea surface temperature (SST) gradient in the equatorial western-central Pacific and enhanced Madden-Julian Oscillation (MJO) propagation, driving sustained westerly wind bursts (WWBs) and downwelling Kelvin waves that intensified both events. In contrast, the cold NPMM during 2023/24 induced a negative SST gradient and suppressed MJO activity, resulting in weaker WWBs and limited eastward wave activity, preventing the event from reaching super El Niño intensity. A 2,200-year CESM1 pre-industrial simulation corroborates these observational findings, underscoring the importance of NPMM interference in improving El Niño intensity predictions.

  PublisherOA PDFDOI

• Marine Heatwaves Alter El Niño’s Influence on North American Winter Precipitation Patterns

  2025-09-29

  preprintOpen accessSenior author

  Despite a strong El Niño, the 2023–24 winter produced a North American precipitation pattern that diverged sharply from canonical El Niño teleconnections, with notable anomalies in the Pacific Northwest, Mexico, the Ohio–Mississippi River Valley (ORV), and the northeastern United States. Using storm track clustering and integrated vapor transport (IVT) diagnostics, we show that these deviations were primarily linked to an extensive North Pacific Marine Heatwave (MHW), with additional contributions from warm-phase Pacific Meridional Mode (PMM) conditions. The MHW generated large-scale circulation anomalies that suppressed precipitation in Mexico and the ORV, while enhancing moisture convergence and storm activity in the northeastern U.S. Concurrently, the PMM amplified Pacific Coast storm activity, intensifying precipitation in the Pacific Northwest. These results demonstrate that North Pacific MHWs can strongly modulate—and in some regions counteract—El Niño’s influence on winter storm tracks and precipitation, with the PMM exerting a more targeted regional effect.

  PublisherOA PDFDOI

• Unusual and persistent easterlies restrained the 2023/24 El Niño development after a triple-dip La Niña

  npj Climate and Atmospheric Science · 2025-01-27 · 4 citations

  articleOpen accessSenior author

  The 2023/24 El Niño, emerging after a rare triple-dip La Niña, garnered global attention due to its potential to evolve into an extreme event, given the largest accumulation of warm water in the equatorial western Pacific since 1980. Despite initial expectations, its growth rate unexpectedly decelerated in mid-2023, preventing it from reaching the anticipated intensity. Here, we show through observational analyses that unusual easterly anomalies over the tropical western-central Pacific, persisting after the end of the preceding La Niña, significantly contributed to this slowdown. A prominent east‒west sea surface temperature gradient in the region has been identified as the crucial factor associated with these unusual and persistent easterly anomalies. This temperature gradient is directly attributed to a negative North Pacific Meridional Mode and a deepened thermocline over the Philippine Sea. These findings offer a deeper understanding of the atypical transition from a prolonged multi-year La Niña to an El Niño.

  PublisherOA PDFDOI

• Localization Method for Abnormal Discharge in Distribution Networks Based on Bandpass Filtering and Windowed Cross-Correlation

  2025-08-29

  article

  Accurate localization of abnormal discharge in distribution networks is crucial for improving power supply reliability. To address the reduced accuracy in cross-correlation methods, where traveling-wave-based localization suffers from the superposition of the first wavefront and reflected waves, this study proposes an improved discharge localization method that combines transfer function frequency-domain analysis with crosscorrelation. First, simulations verify that the frequency-domain characteristics of transfer functions at different locations (including branch points) in distribution lines exhibit high consistency. Second, Short-Time Fourier Transform (STFT) analysis reveals that within the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0-10 \text{MHz}$</tex> frequency band, the first wavefront response is significantly stronger than reflected waves. Based on this finding, a bandpass filter is designed to effectively isolate the first wavefront. Finally, a cross-correlation calculation is performed on the purified first wavefront to precisely determine the time difference of wave arrival for fault localization. Simulation results demonstrate that: (1) The proposed method effectively resolves waveform coupling issues; (2) The crosscorrelation coefficient of separated signals approaches 1; (3) The method maintains robustness against line length variations; (4) It adapts to multiple discharge signal types; (5) Compared with conventional cross-correlation methods, it shows significant advantages in decoupling waveforms and improving localization accuracy. The study also identifies high sampling rates (e.g., 100 MHz) as critical for ensuring performance. This method provides a novel and effective solution for enhancing fault localization precision in complex distribution networks.

  PublisherDOI

• Uncertainty in El Niño‐Driven Northwest Pacific Anticyclone Projections Linked to Indo‐Pacific Circulation Changes

  Geophysical Research Letters · 2025-11-19

  articleOpen access

  Abstract The Northwest Pacific anomalous anticyclone (NWPAC) links El Niño to East Asian summer climate, yet its response to global warming remains highly uncertain. Analyzing 48 CMIP5/6 models, this study identifies projected changes in Indo‐Pacific climatological circulation as key drivers of this uncertainty. Models with a stronger weakening of the Indo‐Pacific Walker circulation project deeper thermoclines in the southwest and shallower ones in the subtropical south Indian Ocean, along with a faster ENSO decay. These changes enhance Indian Ocean SST anomalies and strengthen the NWPAC through adjustments in thermocline–SST coupling and Indo‐Pacific air–sea interactions. In contrast, models with weaker circulation changes project reduced Indian Ocean SST anomaly warming and a weaker NWPAC. These findings highlight the Indo‐Pacific climatological wind changes, acting through thermocline–SST coupling and cross‐basin air‐sea interactions, play a critical role in driving intermodel uncertainty in projections of NWPAC and East Asian climate under global warming.

  PublisherOA PDFDOI

• Unraveling tropical Indian Ocean influences on El Niño-driven Northwest Pacific anomalous anticyclone projections under global warming

  Research Square · 2025-06-16

  preprintOpen access
  PublisherOA PDFDOI

• Trans-Basin Linkages Prolong Northwestern Pacific Marine Heatwaves through a Circumglobal Wave Pattern

  2025-07-29

  preprintOpen accessSenior author

  This repository contains the analysis codes and processed data used to produce the figures and results presented in the associated manuscript "Trans-Basin Linkages Prolong Northwestern Pacific Marine Heatwaves through a Circumglobal Wave Pattern". The scripts are written in MATLAB and cover atmospheric wave diagnostics, statistical analyses, and figure generation.

  PublisherDOI

Recent grants

• Decadal Modulation of El Niño Southern Oscillation and Its Interactions with Tropical Pacific Climate

  NSF · $371k · 2009–2012

• Understanding the Dynamics of El Nino-Southern Oscillation (ENSO) Complexity

  NSF · $792k · 2018–2022

• Studies of the Early-1990s Climate Shift in the Pacific and Its Linkage to the Atlantic Multi-decadal Oscillation

  NSF · $850k · 2015–2019

• Understanding the Multi-year El Nino-Southern Oscillation (ENSO): Its Dynamics, El Nino-La Nina Asymmetries, and Climate Impacts

  NSF · $814k · 2021–2025

• Understanding the Central-Pacific El Nino-Southern Oscillation

  NSF · $643k · 2012–2016

Frequent coauthors

• Jun A. Zhang

  University of Miami

  74 shared

• Xin Wang

  Chinese Academy of Sciences

  73 shared

• I.‐I. Lin

  Chang Gung University

  66 shared

• Christina M. Patricola

  Iowa State University

  66 shared

• Chun‐Chi Lien

  National Taiwan University

  65 shared

• Iam‐Fei Pun

  National Central University

  65 shared

• Yi‐Chun Liao

  Taichung Veterans General Hospital

  65 shared

• Derrick Herndon

  University of Wisconsin–Madison

  65 shared

Education

• Ph.D., Atmospheric Sciences

  University of Washington