NTU/CWA-St-Andrews Joint 2025 Workshop
- S2S prediction: from stratospheric polar vortex to tropical ENSO
September 2 – September 5, 2025

Since 2022, National Taiwan University (NTU) and the University of St Andrews have been partner universities. Under this partnership, the NTU–University of St Andrews Joint Seed Funding was launched for the first time in autumn 2024, aiming to support early-stage collaboration and foster future research and academic innovation. In the same year, Dr. Simon Lee joined the School of Earth and Environmental Sciences at the University of St Andrews as a Lecturer. Simon and I had been collaborating since 2021—when I joined the Department of Atmospheric Sciences at NTU—on a study applying machine learning to characterize the spatiotemporal evolution of sudden stratospheric warming, an extreme dynamical event in the stratosphere. Upon learning about the new seed funding opportunity, Simon informed me, and together we began preparing a proposal building on our previous work in stratospheric dynamics.

One recommendation in the proposal call was to strengthen collaboration between universities and operational centres. In response, we reached out to the Central Weather Administration (CWA) in Taiwan, and Dr. Yun-Lan Chen joined our team to help establish a connection between NTU, the University of St Andrews, and CWA. Notably, the current CWA extended-range forecast system has not yet been systematically evaluated for its performance in representing stratospheric circulation. Our proposal incorporates this assessment, and the results are expected to provide valuable guidance for improving CWA’s extended-range forecasting capability. We also invited Dr. Ioana Colfescu to collaborate, given her expertise in climate prediction and machine learning.

To support communication, accelerate research progress, and promote educational exchange between the two universities, we organized the NTU/CWA–St Andrews Joint 2025 Workshop from 2–5 September 2025 at both the Department of Atmospheric Sciences at NTU and the CWA. The first day featured scientific seminar presentations by Dr. Simon Lee and Dr. Ioana Colfescu from the University of St Andrews. In the same week, Dr. Maxime Collin (Leibniz Centre for Tropical Marine Research, Germany) and Dr. Wei-Ming Tsai (UCLA) also visited the Department of Atmospheric Sciences at NTU. We coordinated their visits so that all four presentations formed a seminar series on the afternoon of the first day. The event attracted strong interest from students, researchers, and faculty members at NTU, with approximately 100 attendees (see Figure 1). Importantly, the invited scientists introduced new research perspectives—particularly on mid- and high-latitude climate change—bringing fresh ideas and vibrant academic energy into our department.

The second day featured two lectures by Dr. Simon Lee and Dr. Ioana Colfescu, who introduced foundational concepts in stratospheric atmospheric dynamics and demonstrated approaches for decadal prediction using machine learning to students in our department. Following the lectures, they joined students for lunch and extended informal discussions. In the afternoon, Dr. Lee and Dr. Colfescu met individually with faculty members for in-depth conversations on ongoing research, potential collaborations, and opportunities for future educational exchange with the University of St Andrews.

The third day coincided with the 39th Conference on Weather Analysis and Forecasting at the Central Weather Administration (CWA). We arranged two plenary talk sessions for Dr. Simon Lee and Dr. Ioana Colfescu, during which they delivered operationally oriented presentations to CWA staff and exchanged ideas on enhancing CWA’s prediction system beyond the weather timescale (see Figure 2). On the fourth day, we concluded the workshop with a closed-door meeting involving the CWA deputy and the technical team participating in this project. The discussion focused on future research directions and opportunities for continued collaboration between NTU, CWA, and the University of St Andrews.

Workshop agenda

Day1, September 2 (Tuesday) at NTU, room B105

12:00-13:30   Lunch at Green Life

13:30-13:40   Welcome and introduction

13:40-14:20   First plenary talk – Dr. Simon Lee (University of St Andrews)

14:20-15:00   Second plenary talk – Dr. Ioana Colfescu (University of St Andrews)

15:00-15:20   Break

15:20-16:00   Third plenary talk – Dr. Maxime Collin (ZMT, Germany)

16:00-16:40   Fourth plenary talk – Dr. Wei-Ming Tsai (UCLA)

16:40-16:50   Wrap-up

18:00-20:00   Dinner at Gugo Kitchen (曉鹿鳴樓) with NTU-AS faculty members

Day2, September 3 (Wednesday) at NTU, room A206

10:20-11:10   Lecture on stratospheric and tropospheric polar vortex – Dr. Simon Lee

11:20-12:10   Lecture on ENSO prediction and deep learning – Dr. Ioana Colfescu

12:10-13:30   Lunch with students

13:30-15:00   Meeting with faculty members (Yu-Chiao has to teach!)

15:00-15:10   Break

15:10-17:00   Group discussions: 1. AI/machine learning; 2. Ozone

17:00-18:30   Dinner at Din Tai Fun

Day3, September 4 (Thursday) at CWA
(39th Conference on Weather Analysis and Forecasting)

9:00-9:30       Dr. Ioana Colfescu
Beyond Stationarity: Can ML Decipher Future North Atlantic Behaviour in a Warming Climate?

10:30-11:00   Dr. Simon Lee
Biases in stratosphere–troposphere coupling in subseasonal forecast systems

12:00-13:00   Lunch at Cha for Tea

*Yu-Chiao has to teach from 3 pm – 9 pm

Day4, September 5 (Friday) at CWA (room 501)

10:20-12:00   Mini-workshop with CWA crew members