A5078837799- Geology and Paleoclimatology Research
- Groundwater and Isotope Geochemistry
- Climate variability and models
- Isotope Analysis in Ecology
- Tropical and Extratropical Cyclones Research
- Pacific and Southeast Asian Studies
- Pleistocene-Era Hominins and Archaeology
- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Coastal wetland ecosystem dynamics
- Geophysics and Gravity Measurements
- Geological formations and processes
- Climate Change, Adaptation, Migration
- Hydrocarbon exploration and reservoir analysis
- Paleontology and Stratigraphy of Fossils
- Atmospheric chemistry and aerosols
- Geological and Geophysical Studies
- Marine animal studies overview
- Meteorological Phenomena and Simulations
- Atmospheric Ozone and Climate
- Oceanographic and Atmospheric Processes
- Ocean Waves and Remote Sensing
- Geochemistry and Elemental Analysis
- Geological and Geophysical Studies Worldwide
- Hydraulic Fracturing and Reservoir Analysis
Nanyang Technological University
2014-2025
Earth Observatory of Singapore
2013-2025
University of Saskatchewan
2005-2016
University of California, Davis
2013
RATIONALE Compound‐specific stable isotope analysis of amino acids has proven informative to many ecological systems, but only a handful analytical methods are routinely employed. We evaluated simple, rapid procedure in which biological samples undergo short‐duration acid hydrolysis and the resulting derivatized with methyl chloroformate for gas chromatography/combustion/isotope‐ratio mass spectrometry (GC/C/IRMS). METHODS Amino derivatives were separated on polar chromatography column,...
Moisture transport pathway effect offsets glacial forcings, likely explaining a lack of G-IG variability in Chinese cave records.
Abstract We present precipitation isotope data (δ 2 H and δ 18 O values) from 19 stations across the tropics collected 2012 to 2017 under Coordinated Research Project F31004 sponsored by International Atomic Energy Agency. Rainfall samples were daily analysed for stable isotopic ratios of oxygen hydrogen participating laboratories following a common analytical framework. also calculated mean stratiform rainfall area fractions around each station over an 5° x longitude/latitude based on...
Abstract Precipitation isotopes are valuable tracers for understanding the hydrologic cycle and climate variations. Distinct from d‐excess, 17 O‐excess has recently emerged as a promising new tracer of precipitation processes because its insensitivity to moisture source temperature. However, control mechanisms on remain poorly understood. In this study, we evaluated performance GISS‐E2.1 model in simulating isotopes, focusing O‐excess. Through comprehensive analysis, explored how variations...
The intertropical convergence zone (ITCZ) plays a key role in regulating tropical hydroclimate and global water cycle through changes its convection strength, latitudinal position, width. long-term variability of the ITCZ, along with corresponding driving mechanisms, however, remains obscure, mainly because it is difficult to separate different ITCZ variables paleoclimate proxy records. Here, we report speleothem oxygen isotope (δ 18 O) record from southwestern Sulawesi, Indonesia, compile...
Abstract Monthly precipitation samples from Singapore were collected between 2013 and 2019 for stable isotope analysis to further our understanding of the drivers tropical isotopes, in particular, 17 O‐excess. δ 18 O ranges –11.34‰ –2.34‰, with a low correlation rainfall ( r = –0.31, p 0.014), suggesting weak amount effect. d‐excess is relatively consistent has an average value 10.89‰ ± 3.45‰. Compared high‐latitude regions, O‐excess generally falls narrower range 2 47 per meg 21 11 meg....
Abstract. Tropical cyclones have devastating impacts on the environment, economies, and societies may intensify in coming decades due to climate change. Stable water isotopes serve as tracers of hydrological cycle, isotope fractionation processes leave distinct precipitation isotopic signatures. Here we present a record daily measurements from March 2014 October 2015 for Metropolitan Manila, first-of-a-kind dataset Philippines Southeast Asia. We show that variation at our study site is...
Abstract 17 O‐excess is a relatively new water isotope parameter that could potentially provide useful information about the hydrological cycle. Previous works focusing on in polar regions suggest it primarily tracks moisture source relative humidity, but little known how to interpret data lower latitudes. Here we present quasi‐hourly triple oxygen of precipitation collected from two tropical cyclones Texas and Louisiana 2020 understand impacts environmental meteorological processes low‐to...
Abstract Sumatra Squalls, organized bands of thunderstorms, are the dominant mesoscale convective systems during intermonsoon and southwest monsoon seasons in Singapore. To understand how they affect precipitation isotopes, we monitored δ value daily continuously (every second integrated over 30 s) all squalls 2015. We found that 18 O values mainly exhibit a “V”‐shape pattern less commonly “W”‐shape pattern. Variation single event is about 1 to 6‰ with lowest mostly observed stratiform zone,...
Abstract To investigate stable isotopic variability of precipitation in Singapore, we continuously analysed the δ‐value individual rain events from November 2014 to August 2017 using an online system composed a diffusion sampler coupled Cavity Ring‐Down Spectrometer. Over this period, average value (δ 18 O Avg ), lowest Low and initial Init ) varied significantly, ranging −0.45 −15.54‰, −0.9 −17.65‰, 0 −13.13‰, respectively. All 3 values share similar variability, with low δ have value....
Abstract The source area of the Yellow River (SAYR) contributes over one third basin discharge and bears disproportionate significance to water conservation in China. Hydroclimate changes SAYR, therefore, have potential far‐reaching socioeconomic consequences. However, major drivers SAYR hydroclimate remain poorly understood, largely due limited hydroclimatic records. Here, we analyzed organic, carbonate contents stable isotopes 14 C‐dated sediments from Ngoring Lake reconstruct regional...
The difficulty in constraining the large-scale Asian summer monsoon (ASM) variability Chinese region (CMR) during glacial Termination II lies our limited knowledge of western part, primarily due to sparse paleoclimate records. To get a better picture ASM II, we examined precisely dated stalagmite δ18O record between 133.1 and 127.0 kyr B.P. from Wanxiang Cave located at ASM's northern edge China. In combination with published data this cave, have identified 'Weak Monsoon Interval' (WMI)...
Abstract Despite the recent recognition of 17 O‐excess as a promising new tracer for hydrological processes, our knowledge control mechanisms underlying in tropical regions remains limited. To understand how microphysical processes during convection affect precipitation isotope ratios, particularly O‐excess, Singapore, we collected samples at minute intervals from six rain events associated with cold surges Northeast Monsoon seasons and analyzed their triple oxygen isotopes. Our results show...
Abstract Due to limited water vapor measurements, isotopes have been traditionally estimated under the assumption of isotopic equilibrium between rain and below cloud base. However, recent advancements in analytical instruments allow more measurements that challenged this assumption. To enhance our understanding rain‐vapor interactions base tropical regions, we established an automated system measure simultaneously continuously real time at minute intervals Singapore. Among 324 events...
In an effort to evaluate mineral-water isotopic exchange during cyclic steam stimulation (CSS), solutions and <2 μm berthierine-dominated solids from the Clearwater Formation oil sands of Alberta, Canada were analyzed for stable isotope compositions before after reaction in autoclaves 1008 h at 250 °C. There was no significant change solution δ18O δ2H, which is consistent with high water/mineral ratio used experiments. The showed a marked decrease both δ2H following Pre-run have +9.5 +12.9‰...
Chemical reactions between oil-sands and injected steam or condensate during cyclic stimulation (CSS), commonly used to mobilize heavy oil bitumen, result in decomposition of pre-existing minerals formation new phases including clay minerals. These changes can reduce reservoir permeability limit hydrocarbon recovery. In this study, the chemical stable isotope compositions berthierine smectitic contained pre- post-steam Clearwater Formation from Cold Lake, Alberta were analyzed investigate...
Abstract. Tropical cyclones have devastating impacts on the environment, economies, and societies, may intensify in coming decades due to climate change. Stable water isotopes serve as tracers of hydrological cycle, fractionation process leave distinct precipitation isotopic signatures. Here we present a record daily isotope measurements from March 2014 October 2015 for Metropolitan Manila, which is first kind dataset Philippines Southeast Asia, analyze if there an response tropical...