@article{SarrazinKumarBasuetal.2022,
  author    = {Sarrazin, Fanny J. and Kumar, Rohini and Basu, Nandita B. and Musolff, Andreas and Weber, Michael and Van Meter, Kimberly J. and Attinger, Sabine},
  title     = {Characterizing catchment-scale nitrogen legacies and constraining their uncertainties},
  series = {Water resources research},
  volume    = {58},
  journal   = {Water resources research},
  number    = {4},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0043-1397},
  doi       = {10.1029/2021WR031587},
  pages     = {32},
  year      = {2022},
  abstract  = {Improving nitrogen (N) status in European water bodies is a pressing issue. N levels depend not only on current but also past N inputs to the landscape, that have accumulated through time in legacy stores (e.g., soil, groundwater). Catchment-scale N models, that are commonly used to investigate in-stream N levels, rarely examine the magnitude and dynamics of legacy components. This study aims to gain a better understanding of the long-term fate of the N inputs and its uncertainties, using a legacy-driven N model (ELEMeNT) in Germany's largest national river basin (Weser; 38,450 km(2)) over the period 1960-2015. We estimate the nine model parameters based on a progressive constraining strategy, to assess the value of different observational data sets. We demonstrate that beyond in-stream N loading, soil N content and in-stream N concentration allow to reduce the equifinality in model parameterizations. We find that more than 50\% of the N surplus denitrifies (1480-2210 kg ha(-1)) and the stream export amounts to around 18\% (410-640 kg ha(-1)), leaving behind as much as around 230-780 kg ha(-1) of N in the (soil) source zone and 10-105 kg ha(-1) in the subsurface. A sensitivity analysis reveals the importance of different factors affecting the residual uncertainties in simulated N legacies, namely hydrologic travel time, denitrification rates, a coefficient characterizing the protection of organic N in source zone and N surplus input. Our study calls for proper consideration of uncertainties in N legacy characterization, and discusses possible avenues to further reduce the equifinality in water quality modeling.},
  language  = {en}
}
@article{Weigend2015,
  author    = {Weigend, Michael},
  title     = {How Things Work},
  series = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
  journal   = {KEYCIT 2014 - Key Competencies in Informatics and ICT},
  number    = {7},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {1868-0844},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82814},
  pages     = {285 -- 298},
  year      = {2015},
  abstract  = {Recognizing and defining functionality is a key competence adopted in all kinds of programming projects. This study investigates how far students without specific informatics training are able to identify and verbalize functions and parameters. It presents observations from classroom activities on functional modeling in high school chemistry lessons with altogether 154 students. Finally it discusses the potential of functional modelling to improve the comprehension of scientific content.},
  language  = {en}
}
@article{XuDengSandev2020,
  author    = {Xu, Pengbo and Deng, Weihua and Sandev, Trifce},
  title     = {Levy walk with parameter dependent velocity},
  series = {Journal of physics : A, Mathematical and theoretical},
  volume    = {53},
  journal   = {Journal of physics : A, Mathematical and theoretical},
  number    = {11},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1751-8113},
  doi       = {10.1088/1751-8121/ab7420},
  pages     = {26},
  year      = {2020},
  abstract  = {To analyze stochastic processes, one often uses integral transform (Fourier and Laplace) methods. However, for the time-space coupled cases, e.g. the Levy walk, sometimes the integral transform method may fail. Here we provide a Hermite polynomial expansion approach, being complementary to the integral transform method, to the Levy walk. Two approaches are compared for some already known results. We also consider the generalized Levy walk with parameter dependent velocity. Namely, we consider the Levy walk with velocity which depends on the walking length or on the duration of each step. Some interesting features of the generalized Levy walk are observed, including the special shapes of the probability density function, the first passage time distributions, and various diffusive behaviors of the mean squared displacement.},
  language  = {en}
}