Siyuan (Susie) He, BSc MSc

PhD Candidate

Siyuan's current research focuses on eco-hydrological process on Kobresia (Kobresia pygmaea) meadow in northern Tibet.

Biography

Siyuan's first degree was in Physical Geography especially in Vegetation Ecology. She finished her fourth year bachelor project on patterns of the forest-steppe ecotone in Inner Mongolia, China. She also finished a university funded project on environmental archaeology in Henan Province. Her Master's research continued her research on the vegetation dynamics of the semi-arid forest-steppe ecotone, based on which her interest in water-vegetation relationships increased. Her current research focuses on eco-hydrological process on Kobresia (Kobresia pygmaea) meadow in northern Tibet. The project includes applying soil moisture monitoring, water balance modelling and remote sensing techniques to understand the soil water bal ance in mountain-basin areas experiencing changing land surface conditions; to find the linkage between micro- and macro- scale hydrological processes; and to identify water movement along the soil-plant-atmosphere continuum (SPAC).

Career

July 2007- September 2008. Deputy Photo Manager of Archery Venue, the 29th Beijing Olympic Games.

Qualifications

PhD candidate in Physical Geography, Department of Geography, University of Cambridge (2009 – present)
MSc in Plant Ecology, Department of Ecology, Peking University (2006 – 2009)
BSc in Physical Geography, College of Urban and Environmental Sciences, Peking University (2002 – 2006)
BA in Economics, China Centre for Economic Research, Peking University (2002 – 2006)

Awards and scholarships

China Scholarship Council (CSC) Cambridge Overseas Trust (COT) Scholarship, October 2009-October 2012
Dudley Stamp Memorial Award, Royal Geographical Society (with IBG), May 2010
Philip Lake Fund, Department of Geography, February 2010
William Vaughan Lewis Fund, Department of Geography, February 2010
Learning and Research Fund, St John's College, University of Cambridge, May 2010
Hong Kong Research Grant, Royal Geographical Society (with IBG), April 2011
Travel Grant, Cambridge Philosophical Society, February 2011
Philip Lake Fund, Department of Geography, May 2011
Learning and Research Fund, St John's College, University of Cambridge, May 2011
Travel Grant, Cambridge Philosophical Society, May 2011
Research Studentships, Cambridge Philosophical Society, December 2012

Research

The Tibetan Plateau (TP) has one of the most complex climates in the world. Analysis of the water cycle is important for understanding both regional water resources management and global climate change. There is a partially closed hydrological cycle between the basin and surrounding mountains in Northern Tibet. Within this soil-plant-atmosphere continuum, the dominant Kobresia meadow (Kobresia pygmaea) has experienced a lengthy period of drastic degradation. These ecologically degraded soil surfaces may reduce water infiltration and evaporation process, thus weakening the recycling of moisture so that land surface degradation continues due to reduced soil moisture.

Siyuan's research focuses on understanding of the hydrological process under degraded alpine meadow, caused by climate change and human activities. The climatic background and institutional change related behaviour are analysed, as well as the degradation mechanism and current situation of both vegetation and soil properties. The main approaches will be applied to end-member plots: degraded meadow and protected enclosure. Lysimetry is assisted by Eddy Covariance (EC) measurements to assess the amount of water components. Water stable isotopes (¹⁸O and D) are applied to trace the water movement in the soil-plant-atmosphere continuum, and to find water use strategy of the plants.The field work is carried out in Kema, a village in Nagqu County in Northern Tibet. Plot-scale observations are interpreted using a one dimensional finite difference (1-D FD) model to simulate vertical unsaturated water movement.

The objective of this project is to make clear the effect of micro-variation of surface conditions on the whole water balance and to provide an optimum strategy for vegetation and water resource protection.

Publications

Selected publications

Yin, Y., Liu, H., He, S., Zhao, F., Zhu, J., Wang, H., Liu, G. and Wu, X. 2011. "Patterns of local and regional grain size distribution and their application to Holocene climate reconstruction in semi-arid Inner Mongolia, China." Palaeogeography, Palaeoclimatology, Palaeoecology, 307(1-4): 168-176.
Wu, X., Liu, H., Ren, J., He, S. and Zhang, Y. 2009. "Water-dominated vegetation activity across biomes in mid-latitudinal eastern China." Geophysical Research Letters. 36(L04402), doi: 10.1029/2008GL036940.
Yin, J., Guo, D., He, S. and Zhang, L. 2009. "Non-structural carbohydrate, N, and P allocation patterns of two temperate tree species in a semi-arid region of Inner Mongolia." Acta Scientiarum Naturalium Universitatis Pekinensis, 45(3): 519-527.
He, S., Liu, H., Ren, J. and Yin, Y. 2008. "Landform-climate-vegetation patterns and countermeasures for vegetation rehabilitation of forest-steppe ecotone on south eastern Inner Mongolia Plateau." Scientia Geographica Sinica. 28(2): 253-258.
Ren, J., Liu, H., Yin, Y. and He, S. 2007. "Drivers of greening trend across vertically distributed biomes in temperate arid Asia." Geophysical Research Letters. 34(L07707): doi: 10.1029/2007GL029435.

External activities

Fellow of the Cambridge Philosophical Society (2009-)
Executive Editor, Journal of Cambridge Studies (2012- )