Meet the scientists who contribute to the SPECIAL research group.
We are based in the Department of Geography and Environmental Science at the University of Reading.
Prof. Sandy P. Harrison
Professor in Global Palaeoclimates and Biogeochemical Cycles
Sandy is a palaeoclimate diagnostician, using large-scale palaeoenvironmental data syntheses and various types of process-based models to study the interaction of climate and the terrestrial biosphere in the geologic past and the present day. The goal of her work is to use the mechanistic understanding of interactions developed under radically different climate of the past to improve our ability to predict the likely trajectory of future climate and environmental changes. As Co-Chair of the Palaeoclimate Modelling Intercomparison Project (PMIP) and as joint leader of the PMIP Data Working Group, she is committed to promoting the analysis and evaluation of the climate and earth-system models used for future projections. Sandy is a Co-Director of the Leverhulme Centre for Wildfires, Environment and Society, where she is actively promoting the use of palaeodata to explore the controls on fire regimes and for model evaluation. She is also leading a new international consortium (LEMONTREE) to build a next-generation model of the terrestrial biosphere and its interactions with the carbon cycle, water cycle and climate.
Dr Paul Lincoln
Postdoctoral Research Assistant
Paul’s research interests are focussed on investigating environmental, landscape and human responses to intervals of abrupt climate change during the last glacial-interglacial cycle. He has used different proxy techniques to construct hydroclimatic (δ18O isotopes, lake-levels), environmental (e.g. sedimentology, plant macrofossils, charcoal) and chronological (14C dating, tephrochronology) records from sedimentary sequences. These records have been used to assess the timing and phasing of environmental responses to warming and cooling intervals across the North Atlantic seaboard.
Paul is working as part of the Leverhulme Centre for Wildfires, Environment and Society, providing expertise on the distribution, timing and related drivers of palaeowildfires. He is also working on the Reading Palaeofire Database (RPD) which is aiming to develop a global data synthesis of charcoal records in order to analyse regional and global patterns in past wildfire regimes.
Dr Nathanael Harwood
Postdoctoral Research Assistant
Nathanael Harwood is a PDRA on the LEMONTREE project working on phenology modelling. Due to the importance of phenology as a control on the carbon and water cycles, one aim of the project is to develop a global model of deciduous phenology. Nathanael is currently working on novel methods within the field of study, and aims to look at climate and environmental controls on cold deciduous phenology to assess the relative importance of variables like temperature, chilling temperature, and light use. The interannual variability in growing season onset and timing is an area of particular interest as it currently represents a source of uncertainty in the vegetation modelling and carbon cycle research area.
Nathanael was previously a member of the London NERC DTP, where he completed a PhD focusing on the use of climate networks to study key relationships between drivers of the North Atlantic jet stream.
Dr Pablo Paiewonsky
Postdoctoral Research Assistant
Pablo has done research in climate-vegetation biogeophysical feedbacks at high latitudes, by developing and using a large-scale simple eco-hydrological model, coupled to an intermediate-complexity general circulation model, and running simulations to determine the strengths and mechanisms behind those feedbacks. Although his emphasis so far has been on the Earth system’s behavior over the last few million years, he is also interested in past “hot-house” climates, in understanding the weaker pole-equator temperature difference in past warm global climates low-latitude climate-vegetation feedbacks, climate-fire-vegetation feedbacks, in the state- and forcing-dependency of climate sensitivity, and in using stable carbon isotope records to infer environmental conditions in Earth’s past. He is also interested in simplifying theories (optimality, evolutionarily stables strategies, coordination hypothesis, maximum entropy production (MEP) principle) and in using them to predict small-to-large scale characteristics of the Earth system and its components. His current research includes development of the “P model”, an optimization-based model of stomatal conductance and photosynthesis.
Dr Gill Thornhill
Postdoctoral Research Assistant
Gill’s research interests are analysing climate model output to investigate and understand the impact of different forcing factors on the climate. She has worked on multimodal comparisons, focussing on the effect of aerosols and reactive gases on radiative forcing.
She is now working with the PMIP4/CMIP6 set of paleoclimate model experiments covering the Last Glacial Maximum and the Mid-Holocene, with a view to benchmarking the models against paleo climate datasets, and providing a robust comparison of the modelled climate with the climate as reconstructed from paleo data.
Dr Azin Wright
Data Analyst on the LemonTree Project
Azin has interests in environmental modelling and data analysis. A major part of her PhD research was focussed on the comparison of land surface models, as well as sensitivity and uncertainty analysis with the focus on drought. As a PDRA she has analysed the role of vegetation cover, seasons, soil hydraulic scheme, and maximum available water in soil on plant water stress in JULES.
She is currently working as a data analyst on developing and testing a global model to predict optimal leaf area index (LAI).
Esmeralda Cruz Silva
Esmeralda works with late Quaternary databases of pollen records at mid-latitudes. She uses this data to produce vegetation maps as a source of information about spatial dynamics of plant communities and climate through time.
Currently her PhD work is centred at reconstructing spatio-temporal changes of vegetation and climate in the Mediterranean region using Holocene pollen data from the EMBSeCBIO database, the European Pollen Database (EPD), the African Pollen Database (APD) and the Modern Pollen Data for Climate Reconstructions (SMPDS). As part of her research, she both developed from the literature and by SPECIAL group members to assess their robustness.
Olivia is a PhD student in the Life Sciences Department at Imperial College, part of the latest QMEE (Quantitative Methods in Ecology and Evolution) cohort and a member of the Leverhulme Centre for Wildfires, Environment and Society. Her primary interest is exploring the impact of CO2 on fire regimes and ecosystems in rapid warming events (notably the Dansgaard-Oeschger events). As part of her PhD, she is working towards building a global fire model that, coupled with a dynamic global vegetation model would allow for improved simulations and predictions of the effect of increasing atmospheric CO2 on the global fire regime and associated impacts on ecosystems. Notably, she is interested in exploring the potential for ecosystem shifts driven by fire disturbances.
David aims to reconstruct paleo fire regimes in the northern extratropics over glacial and interglacial climate changes. During his PhD, he will address this by using charcoal data from the global charcoal database and further unpublished paleocharcoal records.
Furthermore, he is interested in understanding how fire regime shifts over these timescales may relate to vegetation change, and will use various pollen databases to understand feedbacks between fire and vegetation in the context of large scale changes in climate.
Alexander’s primary research interest is to investigate wildfire models and to improve their capacity to represent the ecological impacts of future wildfire changes. He is also interested in investigating whether controls on wildfire vary regionally, and how this is represented by different fire models.
Currently, he is working on analysing the relationship between burnt area and different biophysical variables and other variables, such as above ground biomass. He is using the INFERNO3 global fire model in perturbed-parameter experiments in order to help address the above questions.
Alexander is currently studying for a QMEE PhD at Imperial University.
Mengmeng focuses on Earth system feedback. Her previous master’s work was developing a more rigorous theory for palaeoclimate reconstruction, which showed that WA-PLS is a special case of the theory when taxa tolerances are all equal and this new theory has greatly reduced the compression bias in WA-PLS. This would help with the current PhD project by providing a clearer past.
Her current work is to explore the potential relationships between SST (sea surface temperature), CO2 and dust. When you look back into the data of SST, CO2 concentration and dust between glacial and interglacial periods gained from the ice core, you would find a very similar trend in the changes of SST and CO2 concentration, and some key changes were often related to the abrupt increase of dust, so there might be some potential relationships between them. This would hopefully reveal the potential hidden rules of Earth system feedback and provide some very useful information for the feedback today.
Giulia works at developing mathematical models to predict vegetation response to climate change. With a background in ecology and eco-physiological processes, she has a strong interest in how plant interact with their environment – and vice versa – and how these interactions can be translated into mathematical models and have an impact on the atmospheric composition.
She is currently involved in a PhD project at the Imperial College London, that is carried out in collaboration with the European Centre for Medium-Range Weather Forecasting (ECMWF) and the University of Reading. Her PhD work involves the deployment of a new ecosystem model that combines satellite observations with eco-evolutionary optimality theory to predict canopy-level conductance and improve medium-range weather forecasting.
Sarah investigates monsoon dynamics over the Holocene period (the last 12,000 years) using palaeoclimate records of hydrological change, including speleothem and lake-level data. Her research involves the analysis and comparison of these records to reconstruct changes in the extent and magnitude of northern and southern hemisphere monsoons, and comparison of these reconstructions with climate models.
Currently, her work is focused on reconstructing the spatio-temporal evolution of regional monsoons using oxygen isotope data from speleothems, utilising the SISAL (speleothem isotope synthesis and analysis) database. By comparing speleothem-based palaeoclimate observations with climate model simulations, the forcing mechanisms and internal interactions controlling monsoon evolution can be investigated.
Luke’s research is focussed on investigating the effects of anthropogenic land-use change on fire regimes during the pre-industrial era, against the context of climate-driven changes. His work involves the analysis of charcoal-based records of paleofires, pollen-based information on changes in land cover, and archaeological data on population changes and land use during the Holocene, as well as analysis of existing climate and fire-enabled vegetation model simulations.
Luke will be working as part of the Leverhulme Centre for Wildfires, Environment and Society. As part of this PhD project, he is also hoping to design and implement new experiments with a fire-enabled vegetation model to test the impact of changing climate and LULC on fire regimes in the past.
Mark examines rapid climate change and its effect on vegetation using pollen accumulations in lake sediments. He examines modern pollen assemblages and uses the relationships between pollen and climate to infer changes in climate variables through time.
His current work focuses on the last glacial (~20,000 years ago to ~120,000 years ago). During this time, there are at least 20 periods of rapid temperature increases (Dansgaard-Oeschger cycles) with similar rates of change to what the world is currently experiencing. Pollen assemblages in lake sediments reflect these changes, and the modern pollen-climate relationships may be used to quantitatively reconstruct climate changes during these events. This work helps in answering questions about the fate of vegetation under current and future climate change.
Yicheng has graduated as a MRes student studying ecosystems and environmental change at Imperial College London. She is interested in the relationships between fire, vegetation, climate and human beings in the past time and also at present day. In her master’s project, she built a present-day GLM fire model to explore fire relationships and developed a novel method of palaeofire reconstructions.
Yicheng works as a research assistant in the SPECIAL group as part of the Leverhulme Centre for Wildfires, Environment and Society. Currently, she is focusing on the development of a new method to derive quantitative fire-vegetation relationships using pollen and modern charcoal with the help of Tolerance-Weighted Averaging Partial Least-Squares with sampling frequency correction (fxTWA-PLS) and a present-day GLM fire model. She has tested this approach using the Iberian Peninsula as a case study. This new method opens up the possibility of reconstructing changes in fire regimes quantitatively from pollen records, which are far more extensive than charcoal records. She will expand the study region and investigate palaeofire relationships using the reconstructed fire data in the future study.
Scientific Programmer and Data Manager
Roberto provides programming and database support, including assisting in running and analysing model simulations of past climate & environments and designing & managing palaeoclimate databases.
Previous Team Members
Kamolphat Atsawawaranunt (A)
A constructed and managed databases within the group. These include the SISAL (Speleothem Isotopes Synthesis and Analysis) and GLSDBv2 (Global Lake Status Database version 2) databases. He also managed other on-going databases used within the group such as EMBSecBIO and other pollen databases.
Sean worked on the SISAL database, using pollen reconstructions and outputs of climate models from the 3rd round of the Palaeoclimate Modelling Intercomparison Project using a variational data assimilation technique.
Dr Laia Comas Bru
Laia uses the geochemical characteristics of speleothems (cave formations) to infer past climate variability. These high-resolution records are used to examine the role of regional drivers in shaping local and regional climate conditions, as well as for climate model output evaluation.
Bronwyn focused on the reconstruction of Australian rainfall during the Last Glacial Maximum (approx. 22,000 years ago) and through the Holocene (the last 10,000 years), as a part of the Global Lake Status Database v2.
Dr Guangqi Li
Li studied present and past tree ring behaviour using innovative and creative theory-based approaches. During his time at the SPECIAL group his work included modelling tree ring growth mechanisms and using tree rings in climate data-model comparisons.
Dr Mengna Liao
Mengna’s work in SPECIAL was based around the creation of the Global Lake Status Database v2 to analyse mechanisms of past climate and environmental changes. She used lake basin characteristics to infer sedimentary processes and hydroclimate change in the Tibetan Plateau region.
Dr Łukasz Pawlik
During his research visit, supported by the Polish National Science Centre under the Uwertura 2 fellowship, Łukasz developed a project proposal to quantitatively evaluate the wind impact on European forest ecosystems and windthrows (toppled trees) and its consequences on soils and hillslope microrelief.
Nick reconstructed high resolution environmental change from varved lakes in Mexico and Turkey through the Holocene and explored the potential relationship between environmental and societal change. He was also part of the team developing the Global Lake Status Database v2, focusing in Central America and the Caribbean.
Dr Anne Quillet
Anne’s work in the SPECIAL group included the development of a new model for low-latitude peatlands integrating vegetation, carbon and hydrological dynamics and the modelling of the impacts of peat fire on peatlands carbon balance.
Sam ran statistical models investigating the relationships between fire, climate and fire-adapted functional traits in fire-prone biomes of Australia.
Dr Richard Vachula
As part of the Leverhulme Centre, his work focused on understanding global and regional fire histories and their drivers, comparing model and palaeofire data, and calibrating palaeofire proxies to their carbon cycle impacts.
Dongyang focused on reconstructing climate and vegetation changes in semi-arid Spain from the Last Interglacial (~130,000 yr BP) to the recent times and improving the paleoclimate reconstruction method.