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Category: science plan

HEPEX 10 years ago: Did the vision come true?

HEPEX 10 years ago: Did the vision come true?

Contributed by John Schaake and Roberto Buizza In December 2003, in our ‘Proposal for an International Hydrological Ensemble Prediction Experiment (HEPEX)’, we wrote that: ‘the main objective how HEPEX is to bring the international hydrological community together with the meteorological community to demonstrate how to produce reliable “engineering quality” hydrological ensemble forecasts that can be used to assist the water resources sector to make decisions that have important consequences for the economy and for public health and safety’ () In…

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TIGGE and the multi-model approach in hydrology (a brief review)

TIGGE and the multi-model approach in hydrology (a brief review)

The multi-model approach is well established and popular in hydrological forecasting and modelling. For example, Shamseldin et al. (1997) showed different methods of combining the output of different hydrological models and this HEPEX post raises a number of challenges of multi-model approaches. Therefore, it comes as no surprise that the THORPEX Interactive Grand Global Ensemble (TIGGE, Bougeault et al., 2010) archive, which contains ensemble forecasts by many different centres around the globe (access here), has been attracting increasing attention among…

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Research Projects!

Research Projects!

Hydrological Ensemble Prediction is a relatively young research field with a large amount of opportunities and unexplored scientific topics (see Science and Implementation Plan). There are numerous research grants, research projects, fellowships and PhD/MSc thesis dealing with issues described in the science plan. Some of the existing projects have already been described on this HEPEX site (see here). Knowing more about what people are doing can help us in better focusing our efforts and exchanging methods and practices. This post…

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HEPEX-SIP Topic: Hydrologic data assimilation (2/2)

HEPEX-SIP Topic: Hydrologic data assimilation (2/2)

Contributed by Liu Yuqiong, Albrecht Weerts and Hamid Moradkhani The following challenges and research needs are based on the paper by Liu et al. (2012). The need for transitioning of hydrologic DA research into effective operations has become increasingly recognized in the wake of frequent occurrences of extreme events in recent years and increasing availability of new observations. Several theoretic or mathematical challenges need to be addressed before hydrologic DA can fully benefit operational forecasting. Issues include the high nonlinearity…

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HEPEX-SIP Topic: Hydrologic data assimilation (1/2)

HEPEX-SIP Topic: Hydrologic data assimilation (1/2)

Contributed by Albrecht Weerts, Liu Yuqiong and Hamid Moradkhani What is hydrologic data assimilation? Data assimilation is the process in which model and measurements are combined to provide, in the context of HEPEX, more accurate and reliable forecasts. The term data assimilation includes model calibration, input, state & parameter updating and postprocessing (‘output updating’). Statistical postprocessing (as defined in the HEPEX SIP Topic Postprocessing) could be viewed as a special case of data assimilation. The figure below gives a general…

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