Date: 18th Jun 2024, Tuesday (11:00am – 12:00pm)
Presenter: Jeremie Houssineau (NTU)
Topic: A dedicated representation of epistemic uncertainty for better decision making

Abstract:
Sound decision making requires a reliable quantification of the uncertainty in the underlying problem. To this end, the different types of uncertainty should be identified and dealt with specifically. Although it is already common in the Machine Learning literature to distinguish between epistemic uncertainty, due to lack of knowledge, and aleatoric uncertainty, due to randomness, most uncertainty quantification methodologies use probability theory to represent both, hence limiting the practical consequences of such a distinction. In this talk, I will present an alternative framework for modelling epistemic uncertainty, called possibility theory, and I will illustrate how this approach allows for more nuanced decision making. Considered applications will include data assimilation, robust inference, active learning and reinforcement learning.

Speaker Profiles:
Jeremie Houssineau is an Assistant Professor in the Division of Mathematical Sciences at NTU since January 2024, and an honorary Associate Professor in the Department of Statistics at the University of Warwick. His research interests include possibility theory, Bayesian statistics, multi-target tracking, data assimilation, and reinforcement learning, with applications in Defence and Security, Space, Biology, and Healthcare.

Date: 2nd Jul 2024, Tuesday (11:00am – 12:00pm)
Presenter: Paul Field (UK Met Office)
Topic: Cloud-aerosol interactions in the UM and some machine learning

Abstract:
Clouds remain a large source of uncertainty for both NWP and climate. First, I will show results from the UM comparing observations of volcanic and ship aerosol plumes interacting with cloud and model simulations. These convenient plume sources combined with satellite monitoring provide a critical assessment of the ability of models to represent these interactions. Second, I will present a machine learned approach to representing sub-grid ice cloud fraction, showing training results and the impact on AMIP simulations.

Speaker Profiles:
Prof. Paul Field is a Science Fellow at the Met Office within Atmospheric Processes and Parametrizations (APP) and a Chair at the University of Leeds Institute for Climate and Atmospheric Science. He has worked on clouds using aircraft and laboratory observations and modelling since 1996 at the Met Office’s Met Research Flight and at NCAR (2004-2007) before returning to develop the model cloud physics in the UM.

Date: 9th Jul 2024, Tuesday (2:00pm – 3:00pm)
Presenter: Sharon Seah (ISEAS)
Topic: Southeast Asia’s perceptions of climate challenges

Abstract:
As climate change impacts intensify and affect more people in Southeast Asia, the urgency for a strong and unified climate agenda is gaining momentum. Regional governments are pledging more ambitious climate targets, while businesses and environmental groups are integrating climate considerations into their practices. The “business-as-usual” approach is no longer viable. But how do Southeast Asian citizens perceive these efforts and their countries’ climate policies? The Climate Change in Southeast Asia Programme at the ISEAS-Yusof Ishak Institute launched the Southeast Asia Climate Outlook Survey in 2019 which has since become an annual survey aimed at understanding climate awareness and perceptions among Southeast Asian citizens. This seminar will unpack the fourth edition of the Survey which examines regional attitudes and concerns regarding climate change, government policies and actions, and the role of various stakeholders in climate action. Additionally, it gathered opinions on renewable energy transition, agriculture and food security, and international cooperation.

Speaker Profiles:
Ms Sharon Seah is Senior Fellow and concurrent Coordinator of the ASEAN Studies Centre and the Climate Change in Southeast Asia Programme at the ISEAS – Yusof Ishak Institute. Prior to academia, Ms Seah spent 15 years in the Ministry of Foreign Affairs of Singapore and the National Environment Agency. Her research interests are in ASEAN, multilateralism, rule of law, and climate change. Ms Seah graduated with a Master in Public and International Law from the University of Melbourne in 2018. She is co-editor of 50 Years of ASEAN and Singapore (World Scientific: 2017) and editor of Building a New Legal Order for the Oceans (NUS Press: 2019) by Tommy Koh. She is also the lead author of The State of Southeast Asia Survey Report and the Southeast Asia Climate Outlook Survey Report.

Date: 16th Jul 2024, Tuesday (11:00am – 12:00pm)
Presenter: Jason Lee (NUS)
Topic: Humans in a warming world – more than just heat injuries and productivity losses

Abstract:
While heat stress is the effect of the environment on the individual, heat strain is the resultant thermal load the body experiences predominantly from the weather, workload and clothing. Although heat stress is typically associated with outdoor work, it is also present in indoor workplace environments involving processes that emit radiant heat with inadequate ventilation. Workers, including military personnel, firefighters, law enforcers, construction workers, healthcare workers, gig workers and food stall hawkers are particularly affected by the heat. Heat stress not only increases the risk of heat injury but can also interfere with work productivity. In addition, heat stress can compromise decision making, thereby increasing the risk of accidents. Challenges associated with heat stress and solutions will be presented. Extreme heat will become more intense and frequent. It hurts the whole society and we must take urgent actions now to heatproof our people.

Speaker Profiles:
Prof. Jason Lee is an Associate Professor at the Yong Loo Lin School of Medicine, National University of Singapore. He co-leads the Human Potential Translational Research Programme and directs the Heat Resilience and Performance Centre. Jason co-chairs the Heat Injury Clinical Practice Guidelines at the Ministry of Health and chairs the Scientific Committee on Thermal Factors at the International Commission on Occupational Health. He is on the management committee at the Global Heat Health Information Network and leads the WHO-WMO Southeast Asia Heat Health Node to scale up efforts in managing the complex health risks posed by rising ambient temperatures.

Date: 23rd Jul 2024, Tuesday (11:00am – 12:00pm)
Presenter: Pavel Tkalich (NUS/TCOMS)
Topic: Sea level trend and Low-Frequency Variability of South China Sea

Abstract:
The low-frequency sea level variability in the South China Sea (SCS) is examined using high-resolution regional ocean model simulations spanning the last six decades. The analysis reveals interdecadal oscillations with a periodicity of 12-13 years as the dominant mode of sea level variability in the SCS. The fluctuations in the Luzon Strait transport (LST) are identified as the primary driver of interannual to interdecadal sea level variability, rather than atmospheric forcing within the SCS. Luzon Strait transport shows a weakening trend in the last six decades, resulting in higher heat accumulation and larger steric expansion in the deep SCS. The ocean mass redistribution acts as a mechanism to balance the contrasting steric-induced sea level changes over the deep SCS and shallow continental shelves.

Speaker Profiles:
Dr. Pavel Tkalich is Principal Research Fellow at National University of Singapore (NUS) and is holding joint appointment at Technology Centre for Offshore and Marine, Singapore (TCOMS). His research is directed to unite Climate Change and Variability, Ocean and Coastal Dynamics, Sea level trend and extremes, Environmental Impact Assessment.

Date: 30th Jul 2024, Tuesday (11:00am – 12:00pm)
Presenter: Sandeep Sahany (CCRS)
Topic: Singapore’s Third National Climate Change Study

Abstract:
As a follow-up of Singapore’s Second National Climate Change Study (V2) released in 2015, Singapore’s Third National Climate Change Study (V3) provides the required high-resolution climate change projections for Singapore (grid resolution of 8km and 2km) and the wider Southeast Asia region (grid resolution of 8km), by dynamically downscaling the coarse resolution global climate model data used in IPCC AR6. Key findings from V3 and the V3 Data Visualisation Portal containing the stakeholder and science reports, images, brochures, videos, infographic, and related materials were released earlier this year. This new data set forms the basis for impact studies and adaptation planning to help safeguard Singapore from the adverse effects of climate change.

Speakers Profiles:
Dr Sandeep Sahany is a Deputy Principal Research Scientist at the Centre for Climate Research Singapore (CCRS). He leads the Climate Projections and Extremes Branch at CCRS. His team of research scientists were responsible for delivering a major part of Singapore’s Third National Climate Change Study (V3). He has published around 50 research articles in international journals, and delivered many talks at national and international conferences, meetings, and workshops.

Date: 6th Aug 2024, Tuesday (10:00am – 11:00am)
Presenter: Jianjun Yu (CCRS)
Topic: Historical and Future Heat Extremes and Exposures in Southeast Asia

Abstract:
Heat extremes pose a growing challenge to the world, particularly in Southeast Asia (SEA), where the projected increase of population, urbanization, and economic expansion amplifies the vulnerability to heat extremes. In this talk, based on ERA5-Land reanalysis datasets, the historical heatwave events and its characteristics in terms of intensity, duration and frequency will be firstly discussed. Furthermore, utilizing the recent high-resolution regional climate change projections from Singapore’s Third National Climate Change Study (V3), we assessed the projected change in future extreme temperature characteristics (i.e. maximum temperature, distribution shift, exceedance rate and heatwaves etc.) in SEA under three emission scenarios. Our findings indicate a consistent increase in frequency of heat extremes across all scenarios in SEA, with a sustained longer duration. Last, the social economic and population exposure to extreme heat and the potential impacts will be discussed.

Speaker Profiles:
Dr. Jianjun Yu is senior research scientist in Centre for Climate Research Singapore, Meteorological Service Singapore (CCRS, MSS). He participated in Singapore’s Third National Climate Change Study for climate projections assessment especially in extreme temperatures and heat stress over Southeast Asia and Singapore. He has the academic background of physical geography, GIS and hydrology and water resources management. He participated in many natural hazard risk assessment projects in drought, flood, landslide, tsunami and chemical spills across China and Southeast Asian counties. He was also a specialist in spatial information technology with over 10 years’ experience using spatial databases and GIS for geographical data analytics and hydro-informatics software development for examples Autodesk Map3D, DHI MIKE, Schneider water and energy distribution network modelling software and digital twin.

Date: 13th Aug 2024, Tuesday (11:00am – 12:00pm)
Presenter: Arun Ramanathan (CCRS)
Topic: Application of the Universal Multifractal Framework in Meteorology

Abstract:
The concept of universality in complex systems states that only a few parameters out of many are relevant for defining the system since the same dynamical process is repeated scale after scale or the process interacts with many independent processes over a range of scales, resulting in this reduction. In the Universal Multifractal framework only three parameters, are necessary, and they each have different geometrical and physical meanings. This framework also seems to have some advantages in being a physically meaningful, statistically relevant, computationally cheap option for simulating the behaviour of complex systems such as the atmosphere since it readily considers spatiotemporal heterogeneity, and higher-order statistics. Some of Arun’s earlier work in this context will be presented.

Speaker Profiles:
Dr. Arun Ramanathan has over three years of postdoctoral experience at the Hydrology, Meteorology, and Complexity Laboratory at École des Ponts, where he developed multifractal-based simulation methods and analysis techniques for modelling precipitation, temperature, and the hydrological behaviour of complex media. His doctoral research focused on mesoscale atmospheric predictability using spatially anisotropic universal multifractal models. He holds a joint M.Tech-Ph.D. in the field of earth system science and technology from the Centre for Ocean, River, Atmosphere, and Land Sciences at the Indian Institute of Technology Kharagpur. Currently, he is part of the Numerical Weather Prediction Branch in the Department of Weather Research at the Centre for Climate Research Singapore (CCRS), where he focusses on NWP post-processing.