Filters

2020 - 20212

More filters

20222
Reset filters

Settings

Author: Wada, Yoshihide × Publisher: Katlenburg-Lindau : Copernicus ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Development of the Community Water Model (CWatM v1.04) – a high-resolution hydrological model for global and regional assessment of integrated water resources management
    (Katlenburg-Lindau : Copernicus, 2020) Burek, Peter; Satoh, Yusuke; Kahil, Taher; Tang, Ting; Greve, Peter; Smilovic, Mikhail; Guillaumot, Luca; Zhao, Fang; Wada, Yoshihide
    We develop a new large-scale hydrological and water resources model, the Community Water Model (CWatM), which can simulate hydrology both globally and regionally at different resolutions from 30 arcmin to 30 arcsec at daily time steps. CWatM is open source in the Python programming environment and has a modular structure. It uses global, freely available data in the netCDF4 file format for reading, storage, and production of data in a compact way. CWatM includes general surface and groundwater hydrological processes but also takes into account human activities, such as water use and reservoir regulation, by calculating water demands, water use, and return flows. Reservoirs and lakes are included in the model scheme. CWatM is used in the framework of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), which compares global model outputs. The flexible model structure allows for dynamic interaction with hydro-economic and water quality models for the assessment and evaluation of water management options. Furthermore, the novelty of CWatM is its combination of state-of-the-art hydrological modeling, modular programming, an online user manual and automatic source code documentation, global and regional assessments at different spatial resolutions, and a potential community to add to, change, and expand the open-source project. CWatM also strives to build a community learning environment which is able to freely use an open-source hydrological model and flexible coupling possibilities to other sectoral models, such as energy and agriculture.
  • Thumbnail Image
    Item
    Understanding each other's models: an introduction and a standard representation of 16 global water models to support intercomparison, improvement, and communication
    (Katlenburg-Lindau : Copernicus, 2021-6-24) Telteu, Camelia-Eliza; Müller Schmied, Hannes; Thiery, Wim; Leng, Guoyong; Burek, Peter; Liu, Xingcai; Boulange, Julien Eric Stanislas; Andersen, Lauren Seaby; Grillakis, Manolis; Gosling, Simon Newland; Satoh, Yusuke; Rakovec, Oldrich; Stacke, Tobias; Chang, Jinfeng; Wanders, Niko; Shah, Harsh Lovekumar; Trautmann, Tim; Mao, Ganquan; Hanasaki, Naota; Koutroulis, Aristeidis; Pokhrel, Yadu; Samaniego, Luis; Wada, Yoshihide; Mishra, Vimal; Liu, Junguo; Döll, Petra; Zhao, Fang; Gädeke, Anne; Rabin, Sam S.; Herz, Florian
    Global water models (GWMs) simulate the terrestrial water cycle on the global scale and are used to assess the impacts of climate change on freshwater systems. GWMs are developed within different modelling frameworks and consider different underlying hydrological processes, leading to varied model structures. Furthermore, the equations used to describe various processes take different forms and are generally accessible only from within the individual model codes. These factors have hindered a holistic and detailed understanding of how different models operate, yet such an understanding is crucial for explaining the results of model evaluation studies, understanding inter-model differences in their simulations, and identifying areas for future model development. This study provides a comprehensive overview of how 16 state-of-the-art GWMs are designed. We analyse water storage compartments, water flows, and human water use sectors included in models that provide simulations for the Inter-Sectoral Impact Model Intercomparison Project phase 2b (ISIMIP2b). We develop a standard writing style for the model equations to enhance model intercomparison, improvement, and communication. In this study, WaterGAP2 used the highest number of water storage compartments, 11, and CWatM used 10 compartments. Six models used six compartments, while four models (DBH, JULES-W1, Mac-PDM.20, and VIC) used the lowest number, three compartments. WaterGAP2 simulates five human water use sectors, while four models (CLM4.5, CLM5.0, LPJmL, and MPI-HM) simulate only water for the irrigation sector. We conclude that, even though hydrological processes are often based on similar equations for various processes, in the end these equations have been adjusted or models have used different values for specific parameters or specific variables. The similarities and differences found among the models analysed in this study are expected to enable us to reduce the uncertainty in multi-model ensembles, improve existing hydrological processes, and integrate new processes.