Date: 19th Nov 2024, Tuesday (3:00pm – 4:00pm)
Presenter: Hui Su (HKUST)
Topic: Convection, Cloud, Circulation and Climate Change

Abstract:
Climate model simulations show that tropical circulation would experience significant structural changes under global warming, including weakening and poleward expansion of the subtropical descent, and strengthening and tightening of the equatorial ascent, although the magnitudes of these changes vary substantially between models. The tropical circulation changes are closely coupled with convection and cloud properties, which in turn affect long-term global temperature and precipitation responses to increasing greenhouse gases. In this talk, I will present the interactions between convection, cloud and circulation in the context of climate change in both models and observations, with a special focus on cloud feedback and hydrological cycle.

Speaker Profiles:
Prof. Hui Su is a Global STEM Professor and Chair Professor in the Department of Civil and Environmental Engineering, and the Executive Director of the Space Science and Technology Institute at the Hong Kong University of Science and Technology. She co-led the successful launch of the first HKUST satellite in 2023 and currently leads the HKUST carbon observatory on China’s Space Station project. Before joining HKUST in 2022, she was a principal scientist and weather discipline program manager at NASA’s Jet Propulsion Laboratory (JPL). Hui Su’s research interests primarily focus on tropical meteorology, climate variability and climate change, and remote sensing. She has published over 140 peer-reviewed articles. In 2024, she received the Banner I. Miller Award from the American Meteorological Society, and she was awarded the NASA Exceptional Scientific Achievement Medal in both 2010 and 2022. Additionally, she is a recipient of the Edward Stone Award and the Lew Allen Award for excellence at JPL. Hui Su is a Fellow of the American Meteorological Society and serves as an Editor for Geophysical Research Letters.

Date: 21st Nov 2024, Thursday (4:00pm – 5:00pm)
Presenter: Ashar Aslam (University of Leeds)
Topic: Severe weather over southeast Asia: from air-sea interaction to Sumatra squalls

Abstract:
The Maritime Continent in southeast Asia experiences extreme rainfall all year round. Patterns in rainfall and deep convection are modulated by processes which operate over a variety of spatial and temporal scales. While extensive research has been conducted into better understanding these processes, several gaps still remain in our knowledge. In this talk, I will be discussing two components of my PhD so far, which aim to address some of these gaps. Firstly, I explore air-sea interactions at the mesoscale and their role in influencing regional atmospheric properties. Using satellite altimetry data, I highlight geographical variability in mesoscale ocean eddy properties across the Maritime Continent. Coupling these results with reanalysis data, I assess whether there is a detectable atmospheric response to the surface anomalies associated with these eddies, which are known, elsewhere in the global ocean, to influence atmospheric boundary layer stability. Secondly, I introduce initial results which investigate the larger-scale drivers of eastward propagation of convection over Sumatra. Many studies have addressed the westward offshore propagation of convection from the Barisan mountains, but very few explore, in depth, propagation in the opposite direction. Extreme rainfall coming from these convective systems can affect eastern Sumatra, peninsular Malaysia and Singapore, the latter of which have historically coined the term ‘Sumatra squalls’. Future work will aim to look into storm-scale dynamics influencing these squalls.

Speaker Profiles:
Ashar Aslam completed an integrated Masters’ in Earth Sciences from the University of Oxford in 2021, before starting his PhD at the University of Leeds, funded by the SENSE Centre for Doctoral Training as part of a Met Office CASE studentship. His primary supervisors are Juliane Schwendike and Simon Peatman (who has recently joined MSS). Now in his final year, Ashar’s PhD has aimed to explore various processes and scale interactions that influence rainfall patterns across the Maritime Continent in southeast Asia.

Date: 29th Nov 2024, Friday (2:00pm – 3:00pm)
Presenter: Xiaosheng Qin (NTU)
Topic: Evaluating Precipitation Extremes in Mainland Southeast Asia under Climate Change Using Bias Correction

Abstract:
Occurrence of extreme weather events has been witnessed to become more frequent and severe in Southeast Asia and their consequences are tremendous considering this region’s large population size, insufficient infrastructure, extensive coastlines, and broad lowlying areas. This study aims to examine the frequency of precipitation extreme indices such as maximum daily precipitation amount using various bias-correction schemes over part of Southeast Asia. The bias-correction schemes were based on quantile delta mapping with different strategies in selecting the data series. Regional climate model (RCM) outputs were used for projecting future changes of rainfall. Frequency analysis was carried out to review the annual peaks of various indicators. The study explored the effect of uncertainty originated from adopting various bias-correction schemes in mapping future frequency of precipitation indices and is valuable in revealing the spatiotemporal distribution of precipitation extremes over large areas under climate change.

Speaker Profiles:
Dr. Xiaosheng Qin is an Associate Professor in the School of Civil and Environmental Engineering at Nanyang Technological University, Singapore. He earned his bachelor’s and master’s degrees from Hunan University, China, and his Ph.D. from the University of Regina, Canada. Dr. Qin primarily teaches Hydrology and Water Resources Engineering at both undergraduate and graduate levels. His research centers on hydrological modeling and extreme weather analysis, climate change impact assessment and adaptative planning, and water resources and environmental systems planning. Dr. Qin has served as a local expert on climate modeling for the Building and Construction Authority (BCA) from 2011 to 2014 and has led or co-led numerous research projects supported by Singapore government agencies, including MND, BCA, MOE, JTC, NParks, EOS, and EWI. He is currently an Associate Editor for the Journal of Environmental Informatics and Water Science and Technology and has served on the editorial boards and as a guest editor for seven international journals. Dr. Qin has reviewed for over 50 scientific journals and authored more than 180 scientific publications (peer-reviewed journal and conference papers), with a recent Google Scholar citation count of 5,291 and an H-index of 43. Since 2022, Dr. Qin was recognized in Stanford University’s list of the World’s Top 2% Scientists.

Date: 3rd Dec 2024, Tuesday (11:00am – 12:00pm)
Presenter: Xiaohui Zhong (Fudan University)
Topic: FuXi: From Medium-range to subseasonal-to-seasonal forecasts

Abstract:
Skillful subseasonal forecasts are crucial for various sectors but present significant scientific challenges. Recent advancements in machine learning have led to machine learning models that outperform leading numerical forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF) in medium-range forecasts, though they still lag behind conventional models at subseasonal timescales. FuXi model team developed FuXi Subseasonal-to-Seasonal (FuXi-S2S), a machine learning model capable of generating global daily mean forecasts for up to 42 days, encompassing five upper-air atmospheric variables across 13 pressure levels and 11 surface variables. Trained on 72 years of daily statistics from ECMWF ERA5 reanalysis data, FuXi-S2S exceeds ECMWF’s state-of-the-art Subseasonal-to-Seasonal model in ensemble mean and forecasts for total precipitation and outgoing longwave radiation, significantly improving global precipitation predictions. This enhancement is largely due to FuXi-S2S’s ability to capture forecast uncertainty and extend skillful Madden-Julian Oscillation (MJO) predictions from 30 to 36 days. Additionally, FuXi-S2S effectively identifies teleconnections associated with the MJO and serves as a valuable tool for discovering precursor signals, offering new insights for researchers and potentially reshaping Earth system science.

Speaker Profiles:
Dr. Xiaohui Zhong is a postdoctoral researcher at the Department of Artificial Intelligence Innovation and Incubation Institute of Fudan University, and a research scientist at the Shanghai Academy of Artificial Intelligence for Science. He obtained a PhD degree in Mechanical Engineering from the University of California San Diego. He was an algorithm expert at Alibaba Damo Academy before joining Fudan University. He is the chief atmospheric scientist at FuXi modeling team. His research interests are primarily in improving weather forecasting and data assimilation with machine learning models.