Picture of                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     Simon Micheal Papalexiou

Simon Micheal Papalexiou Assistant Professor

Department of Civil, Geological & Environmental Engineering | Global Institute for Water Security

Academic Background

  • Research Associate, Stochastic modelling and global changes, University of California, Irvine, USA
  • Ph.D., Stochastic and statistical hydrology, National Technical University of Athens, Greece
  • M.Sc., Water Resources, National Technical University of Athens, Greece
  • B.Sc., Environmental Sciences, University of Aegean, Greece

Research Interests and Expertise

Simon Michael Papalexiou focuses on developing advanced stochastic models, downscaling schemes, and probability tools for hydrologic engineering and hydroclimatology. Hydroclimatic processes such as precipitation, wind, temperature, and their extremes, are described by different spatiotemporal dependencies and probability distributions. This complexity led to a large number of ad hoc modeling schemes. Simon, works on unified and precise stochastic modeling schemes and aims to increase our understanding on the spatiotemporal and probabilistic structure of hydroclimatic processes and to offer a complete set of novel stochastic tools for stationary and non-stationary cases. His works extend on developing efficient spatiotemporal downscaling methods enabling reliable reproduction of the fine-scale characteristics of precipitation and temperature. His overall goal is to improve the probabilistic prediction of risk and severity of extreme events, advance the quantification of uncertainty, and create reliable diagnostics and methods to detect and assess the significance of observed changes and trends with a focus on extreme events. He mainly performs global analyses using large databases comprising thousands of stations.

Research Keywords

  • Stochastic modelling of hydroclimatic processes
  • Statistics of extremes
  • Climate change diagnostics
  • Hydroclimatic variability
  • Big-data analysis

Publications

Papalexiou, S.M., 2018. Unified theory for stochastic modelling of hydroclimatic processes: Preserving marginal distributions, correlation structures, and intermittency. Advances in Water Resources 115, 234-252. https://doi.org/10.1016/j.advwatres.2018.02.013

Papalexiou, S.M., Markonis, Y., Lombardo, F., AghaKouchak, A., Foufoula-Georgiou, E., 2018. Precise Temporal Disaggregation Preserving Marginals and Correlations (DiPMaC) for Stationary and Nonstationary Processes. Water Resources Research. https://doi.org/10.1029/2018WR022726

Papalexiou, S.M., AghaKouchak, A., Foufoula‐Georgiou, E., 2018. A Diagnostic Framework for Understanding Climatology of Tails of Hourly Precipitation Extremes in the United States. Water Resources Research. https://doi.org/10.1029/2018WR022732

Papalexiou, Simon Michael & AghaKouchak, Amir & E. Trenberth, Kevin & Foufoula-Georgiou, Efi. (2018). Global, Regional, and Megacity Trends in the Highest Temperature of the Year: Diagnostics and Evidence for Accelerating Trends. Earth's Future. 6. https://doi.org/10.1002/2017EF000709

Papalexiou, S.M., Dialynas, Y.G., Grimaldi, S., 2016. Hershfield factor revisited: Correcting annual maximum precipitation. Journal of Hydrology. 542. https://doi.org/10.1016/j.jhydrol.2016.09.058

Papalexiou, S.M., Koutsoyiannis, D., 2016. A global survey on the seasonal variation of the marginal distribution of daily precipitation. Advances in Water Resources 94, 131-145. https://doi.org/10.1016/j.advwatres.2016.05.005

Papalexiou, S.M., Koutsoyiannis, D., 2013. Battle of extreme value distributions: A global survey on extreme daily rainfall. Water Resour. Res. 49, 187-201. https://doi.org/10.1029/2012WR012557

Papalexiou, S.M., Koutsoyiannis, D., Makropoulos, C., 2013. How extreme is extreme? An assessment of daily rainfall distribution tails. Hydrol. Earth Syst. Sci. 17, 851-862. https://doi.org/10.5194/hess-17-851-2013

Papalexiou, S.M., Koutsoyiannis, D., 2012. Entropy based derivation of probability distributions: A case study to daily rainfall. Advances in Water Resources, Space-Time Precipitation from Urban Scale to Global Change 45, 51-57. https://doi.org/10.1016/j.advwatres.2011.11.007