Subsequent modelling may also be needed, for calculations of indicators, ocean currents or modelling of connectivity etc. By simulating only a part of the Earth in a regional model more detailed information can be achieved, although data from a global model is needed. A global model is required to simulate the global climate. The regional models cover Europe and have a resolution (size of the grid boxes) of around 12.5x12.5 km.įigure. In this service several regional climate models forced with several different global models are used. In that way the regional model also considers what happens outside the domain. The results from a global climate model governs what happens outside the model domain in the regional model. In that way more detail can be achieved for a smaller region without using too much computer power. The grid is put on a smaller region in the regional model, for example Europe. The grid in a global climate model is sparse, which gives less details on the regional scale. The time evolution of different meteorological parameters are calculated in each cell of the grid.Ĭlimate models create enormous amounts of information and requires therefore large amounts of computer power, which means that the 3-dimensional grid must be restrained. Such models are called global climate models. To get good results processes outside the entire atmosphere must be considered, that is around the globe and up in the air. In the model the atmosphere is divided into a 3-dimensional grid, across the surface and upwards. These are 3-dimensional representations of the atmosphere, the land surface, oceans, lakes and ice. Climate modelsĬlimate models are used to calculate future climate. The S-HYPE models contains about 40 000 sub-catchments to simulated Swedish hydrology, but the results are summarised to 262 named geographical areas in the service. The hydrological model describes water’s path through the ground, lakes and other water bodies, and how much water that is returned to the atmosphere through evaporation or return to the oceans. Before impact modelling with S-HYPE, these parameters are therefore bias adjusted to fit the calibration of the hydrological model. The climate models suffer from systematic errors, so-called bias, in the forcing variables temperature and precipitation. The climate model simulations are a part of the international research programme CORDEX () and Copernicus Climate Change Service (). The results of climate model simulations are refined for each of the counties in Sweden, and cover the period 1951-2100. Th climate models describe the connections between processes in the atmosphere, on the surface and in the oceans. In climate model calculations, information on future changes in the atmosphere are used. The results are summarised in 262 geographical areas of the service. The climate data are then used to force the hydrological model S-HYPE, in order to describe hydrological processes. The service builds on scenarios from multiple regional climate models forced by several different global climate models. The allocated monthly flow rates in the three Dams steering program are not sufficient to preserve the Zab River life.These pages present the development of water in the ground, lakes and other water bodies as a consequence of the changing climate of the 21st century. The results indicate that the order of 35%, 17% and 18% of the mean annual flow are to be maintained for the upper, middle and downstream river reaches, respectively. Ecological needs of the riverine key species (mainly Barbus capito fish), river geometries, natural flow regime and the environmental status of river management were the main indices for determining the minimum flow requirements. Tennant, Tessman, flow duration curve analysis, range of variability approach, Smakhtin, flow duration curve shifting, desktop reserve and 7Q2&10 (7-day low flow with a 2- and 10-year return period)) two hydraulic methods (slope value and maximum curvature) and two habitat simulation methods (hydraulic-ecologic, and Q Equation based on water quality indices) were used. ![]() The main objective of this study came from the construction of three dams and inter-basin transfer of water from the Zab River to the Urmia Lake. This paper addresses the evaluation of environmental flow requirements in three reaches along a typical perennial river (the Zab transboundary river, in north-west Iran), using different hydraulic, hydrological and ecological methods. The assessment of environmental flows in rivers is of vital importance for preserving riverine ecosystem processes.
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