Date: 1st Nov 2023, Wednesday (11:00am – 12:00pm)
Presenter: Peter Heng (MSS)
Topic: Takeaways from the WCSSP SE Asia Regional Science Workshop

Abstract:
The Weather and Climate Science for Service Partnership Southeast Asia (WCSSP SE Asia) is a collaborative initiative between research institutes in the UK and the Philippines, Malaysia, Indonesia and Vietnam that aims at advancing the understanding of high-impact weather over the region, developing global and regional forecasting systems to better predict these events, and improving how forecasts are translated into warnings and advice. The WCSSP SE Asia Regional Workshop held in Hanoi, Vietnam from 16 to 18 May brought together scientists and forecasters from across the partnership to exchange knowledge and experience on weather phenomena affecting SE Asia, the fidelity of model forecasts, and the communication of forecasts and warnings. This talk will highlight some of the work under this initiative that may be of interest to MSS.

Speakers Profiles:
Peter Heng is a Senior Meteorologist in the Weather Services Division in MSS. His interests are in NWP model evaluation, forecast verification and forecast product development.

Date: 3rd Nov 2023, Wednesday (10:00 – 11:00am)
Presenter: Khairunnisa Yahya (CCRS)
Topic: Environmental Monitoring and Modelling in the Clean Environment Group (CEG)

Abstract:
The Environmental Monitoring and Modelling Division (EMMD) within the Clean Environment Group (CEG) carries out air, water and soil quality monitoring and sampling, as well as air and water quality modelling and research to support NEA’s policy and operations. The presentation will cover the various environmental monitoring and sampling programmes including EMMD’s sensor networks, as well as current and past research undertaken by EMMD and through collaborations with research/academic institutions.

Speaker Profile:
Khairunnisa Yahya was previously from the Environmental Quality Monitoring Department (EQMD) under the Environmental Monitoring and Modelling Division (EMMD), overseeing both the Air Quality Monitoring and the Water and Soil Quality Monitoring Branches in EMMD. She holds a PhD in Atmospheric Science from the North Carolina State University, specializing in Air Quality Modelling. As part of building stronger cross pillar collaboration and capability building in air quality modelling, prediction and research, she is currently doing a 2-year attachment with the Atmospheric Dispersion Modelling Branch under DWR.

Date: 8th Nov 2023, Wednesday (11:00am – 12:00pm)

Presenter: Fangyi Tan (NTU-EOS)
Topic: High-resolution Late Holocene relative sea-level record from coral microatolls in Sentosa, Singapore

Abstract:
Local to regional relative sea-level (RSL) records are needed to shed light on the drivers of RSL change to guide coastal planning and adaptation. However, current understanding of RSL changes in Singapore and the Sunda Shelf are hindered by a lack of high-resolution RSL records. Here, we present the first high-resolution Late Holocene RSL record from coral microatolls in Singapore, located in the middle of the Sunda Shelf. Coral microatolls are fixed biological indicators whose growth are controlled by RSL changes. We compared the relative elevations of fossil and living coral microatolls to produce sea-level index points (SLIPs) that indicate the RSL at a given time in the past. We produced twelve high-resolution SLIPs (<± 0.20 m and <± 26 yrs uncertainties, 2σ) and showed that RSL fell gradually (at rates between 0.2 ± 0.7 mm/yr and 0.1 ±0.3 mm/yr) since ~2800 yrs BP, with slight RSL fluctuations. More high-resolution RSL records are necessary to resolve discrepancies amongst RSL records from the Sunda Shelf and/or decipher spatially-distinct drivers of RSL change in the region.

Speaker Profile:
Fangyi Tan is a final-year PhD student at the Earth Observatory of Singapore. She uses geological proxies like mangrove peat and coral microatolls to study sea-level changes in the past, from 8,000 years ago to present. Her research aims to provide the data to understand the different processes driving relative sea-level change, including processes related to the melting of ice sheets that act on centennial to millennial timescales.

Presenter: Christabel Tan (NTU-EOS)
Topic: Constraining late Holocene sea level using mangroves – A case study from Singapore

Abstract:
The reconstruction of late Holocene relative sea level (RSL) is important to understand the drivers of sea level change and prepare for future sea-level rise. Here, we investigated mangrove environments in Pulau Ubin, Singapore to develop sea-level index points (SLIPs) and reconstruct late Holocene RSL changes. We surveyed vegetation zones to estimate the indicative meaning of mangroves relative to the mean tide level (MTL) and applied the indicative meaning to basal mangrove sediments collected from sediment cores in an upland-mangrove transition area. We used radiocarbon dating of wood, leaf tissue and organic sediment to establish the depositional chronology and applied an Errors-In-Variables Integrated Gaussian Process (EIV-IGP) model to reconstruct the magnitude and rate of RSL change. The indicative range of mangroves in Pulau Ubin is between 1.28 ± 0.01 m MTL and -0.02 ± 0.01 m MTL, which is ~20% reduction in vertical uncertainty than the approach used in previous mangrove-based studies in Singapore. We have produced 8 new SLIPs (>40% mangrove pollen) that show sea levels were slightly below present over the ~2,000 year to ~500 cal. yr BP.

Speaker Profile:
Christabel Tan is a final year PhD student at the Asian School of the Environment. She conducts sedimentology and pollen analysis on modern surface sediments and sediment cores to understand the past sea level changes over the Holocene. She explores mangrove environments to understand pollen as a proxy for sea level changes.

Presenter: Tanghua Li (NTU-EOS)
Topic: Glacial Isostatic Adjustment: Implications for sea-level and beyond, from past to future

Abstract:
Over 400 million people in Southeast Asia live in low elevation coastal zones and are susceptible to future relative sea-level (RSL) rise. Accurate projections of future RSL rely on a good understanding of its history and driving mechanisms such as Glacial Isostatic Adjustment (GIA). Here I will introduce GIA model and its application in Singapore and Southeast Asia through two case studies. We revealed the earliest documented instance of forced human migration driven by rapid sea-level rise (e.g., WMPs) in Southeast Asia by integrating paleotopographic and population genomic analysis. We investigated the sensitivity of the mid-Holocene sea-level highstand to Earth and ice model parameters, revealing that Earth model variation affects the magnitude and ice model variation changes both the timing and magnitude of the highstand. Lastly, we produced a highstand “treasure map” to guide future highstand data collection efforts as the highstand is poorly constrained currently in Southeast Asia.

Speaker Profile:
Dr Tanghua Li is a Senior Research Fellow at the Earth Observatory of Singapore (EOS) Nanyang Technological University (NTU). Dr Li’s research interests include interactions of ice sheets, ocean and solid Earth, and their lasting impact on the Earth system, with a specific focus on modelling the Glacial Isostatic Adjustment (GIA) process with 3D (laterally heterogeneous) model and associated sea-level/ice sheet evolution, vertical land movement, gravity field change during the last glacial cycle. His research contributes to the better understanding of Earth rheological structure and glaciation/deglaciation history, which helps to constrain estimates of future sea-level change and understand the response of ice sheets to climate change. Dr Li is also interested in interdisciplinary studies exploring sea-level change impacts and applications.

Date: 15th Nov 2023, Wednesday (11:00am – 12:00pm)
Presenter: Cheryl Tay (NTU-EOS)
Topic: Land subsidence through the lens of InSAR

Abstract:
Human-induced land subsidence has far-reaching implications on climate change: the over-extraction of groundwater in urban coastal areas causes land to sink and thus exacerbates sea-level rise; excessive soil drainage in vegetated peatlands causes peat to compact and release large amounts of stored carbon as carbon emissions. The severity of these impacts are not well understood given the limited amount of observations available globally, as land subsidence is challenging to map both extensively and with high accuracy. In this talk, I will introduce our project which aims to advance the monitoring of land subsidence by utilising the unique capabilities of Interferometric Synthetic Aperture Radar (InSAR). The project seeks to contribute to informed decision-making and mitigation strategies for sea-level rise and carbon emissions by providing a measurement solution that works over differing land covers.

Speaker Profile:
Cheryl Tay is a PhD candidate in the Asian School of the Environment, Nanyang Technological University. Her research interests are in SAR and InSAR applications, sea-level, and peat subsidence. Prior to her PhD, she worked in the Earth Observatory of Singapore to produce flood and damage maps derived from SAR data to support rapid response efforts following natural disasters.

Date: 22nd Nov 2023, Wednesday (11:00am – 12:00pm)
Presenter: Utkarsh P. Bhautmage (NUS)
Topic: Development and Evaluation of a New Urban Parameterization in the WRF Model

Abstract:
In mesoscale Weather Research and Forecasting (WRF) model, several urban-modeling options exist, such as Single-layer Urban Canopy Model (UCM), Building Effect Parameterization (BEP), and Building Energy Model (BEM). However, these models have limitations in terms of the choice of land surface models (LSMs) and planetary boundary layer (PBL) schemes, the associated computational expenses, and other constraints. In this work, an attempt has been made to explicitly include the urban physics components such as momentum drag, thermal, and moisture aspects into the Pleim-Xiu (PX) LSM and coupled with the Asymmetric Convective Model version-2 (ACM2) PBL scheme in the WRF model. This new urban model (named UACM) incorporates diurnal variation in the street, walls, and roof surface temperatures, modeled using the two-layer force-restore algorithm. Simple radiation treatment is considered to account for shadowing on streets based on the solar zenith angle and building morphology. Heat and moisture flux evolution are considered explicitly on all urban surfaces. The advantages of this novel UACM are simple formulation, more efficient execution, and its requirement for only a few fundamental urban morphological parameters. The real urban data case WRF-UACM simulations are demonstrated over the Pearl River Delta (PRD) economic region in southern China and Delhi region in India. The computationally efficient UACM is expected to perform faster for operational forecasting runs.

Speaker Profile:
Dr. Utkarsh P. Bhautmage is a joint NUS-CCRS post-doctoral research fellow recently joined in the Department of Geography, NUS, Singapore and working with Prof. Matthias Roth. He has obtained his PhD from the Hong Kong University of Science and Technology (HKUST) in the field of Atmospheric Sciences. His primary research focus revolves around the processes involving the interaction between land and the atmosphere. During his PhD, he worked in collaboration with USEPA (North Carolina, USA) on developing a new computationally efficient multilayer urban model within the WRF model mainly to improve the urban meteorology modeling in particular the winds, temperatures, and vertical structure of the atmosphere in the large cities. Prior to joining NUS, he has an experience of working as a researcher at HKUST and IITM-Pune India on implementing WRF-UACM to simulate the urban meteorological conditions and serve its varied applications. Currently, he is working on the development and assessment of the 100 m uSINGV, a customized version of the UK Met Office Unified Model, to predict extreme rainfall and wind in Singapore.

Date: 28th Nov 2023, Wednesday (11:00am – 12:00pm)
Presenter: Hari Vishnu (NUS)
Topic: Acoustic activity due to submarine melting at tidewater glaciers – an indicator of climate-change?

Abstract:
A significant component of sea-level rise is attributed to melting glaciers and ice-sheets in polar regions. At marine-terminating glaciers in these regions, calving and submarine melting at the glacier-water interface accounts for a big chunk of the ice lost. Submarine melting leads to explosion of ice-trapped bubbles underwater which produces a distinct sound similar to ‘frying chips’ that travels over long distances underwater. This sound is a promising remote-sensing medium to characterize ice-loss using relatively cheap equipment over long time-scales and large areas. To evaluate this possibility, we made acoustic measurements at glaciers in Svalbard in 2019 and 2023. Our preliminary results reveal that sound recordings provide many details on the ice-loss processes at the glaciers, and shows a correlation with the water temperature, indicating that acoustics shows promise as a possible method for melt-monitoring at glaciers. In order to understand the sound produced at the glacier terminus, we also deployed robots which sensed close to the glacier terminus using acoustic, temperature, salinity sensors and cameras, and provide insights on the ice-loss processes transpiring at the ice-ocean boundary.

Speakers Profiles:
Hari Vishnu is a Senior Research Fellow at National University of Singapore. His interests include glacier acoustics, machine-learning for underwater applications, bio-acoustics and signal processing in impulsive noise. These are used in a wide range of applications, spanning from biodiversity in Singapore waters to the Arctic ice sheets where glacier melt noise dominates the soundscape. He undertook field campaigns in 2023 to Svalbard to study the acoustics of melting glaciers, and was a Visiting Postdoctoral fellow at the Scripps Institution of Oceanography during 2019-2021 to pursue collaborations on this. He is the Chief Editor on the Oceanic Engineering society (OES) Science outreach magazine Earthzine, and contributing to OES efforts on the UN Decade of Ocean Sciences. In 2019, he was awarded the IEEE OES’s YP-BOOST award which aims to encourage young professionals in oceanic engineering. He is the current Secretary of OES, was the chair of the OES Singapore chapter for 2018-2020 and 2021-2023, Secretary of the Singapore AUV Challenge since 2016.