Why do we need a workshop?
The area of uncertainty estimation in environmental modeling has been sterile in recent years and there has been little real progress. We are stuck at the same questions for a long time and there seems to be little progress in sight.
Why a different workshop style?
We feel that the usual conference style is good in conveying knowledge, but does add little in terms of improving interaction and creating new ideas. We therefore decided on a style that focuses on discussion and brainstorming, and reduces the time spend on presenting existing and already well-known work.
Workshop focus
Uncertainty is an unavoidable element in any hydrologic modeling study. This uncertainty stems from the parameters, the model structure and measurements of input and output data, and initial and boundary conditions. The uncertainty is likely to be particularly severe in basins for which no (or few) measurements of the response variable under investigation are available (e.g. streamflow), since these measurements are normally required to reduce the uncertainty in the parameters. A commitment to quantify uncertainty in hydrologic flux predictions lies at the heart of the PUB initiative. However, methods to estimate and propagate this uncertainty have so far been limited in their ability to distinguish between different sources of uncertainty and in the use of the retrieved information to improve the model structure analyzed. Examples of these approaches are point methods, set-theoretic techniques where the uncertainty is largely treated implicitly, or Bayesian approaches, which currently make strong assumptions about the nature of uncertainties involved.
It is clear that a proper uncertainty framework is required for model/method evaluation / development and the analysis of model predictions. A framework is needed that allows for the explicit incorporation of different sources of uncertainty as well as for the incorporation of multiple sources and types of information. The approach should also allow for the recursive processing of information and provide feedback about structural discrepancies of the evaluated model. There is no clear consensus about how such an approach could be implemented. Also, there is currently little guidance about how information/uncertainties should be considered/evaluated when they are spatially distributed or at different scales.
Workshop objectives
The Workshop aims to bring together a number of international researchers, with expertise in the area of uncertainty analysis in environmental modeling and other fields (to invite new ideas) to work towards the following objectives:
To promote discussion and to critically appraise the current “state-of-the-art” of uncertainty analysis techniques employed in environmental modeling.
To stimulate/introduce new ideas which are so far not part of the current core hydrology calibration/ uncertainty roadmap.
To discuss concepts in an open and frank forum.
To work towards a stated set of beliefs or principles about the main themes explored in the workshop (includes agreements and disagreements, and most importantly the reasons for disagreements).
To work out what we believe to be the future for our science, trends and possible directions?
To publish post workshop manuscripts (journal and/or web publications) that embody a “discussions of principles” approach to the workshop themes. This is necessary to convey the results to the larger hydrologic community.
Define future steps of this working group on uncertainty.
The workshop will help define the agenda of the uncertainty working group and also indicate whether separate
sub-working groups should be formed to tackle some of the science questions. The main questions addressed in this
workshop are:
What is the current state-of-the-art of uncertainty analysis in environmental and
hydrological science and in other relevant fields?
What are the limitations and problems of current methods? What are the bottlenecks that prevent
progress?
What are promising directions for progress in uncertainty analysis in environmental and hydrological
science?
Any method to estimate and propagate uncertainty for dynamic hydrologic models can be brought back to three
fundamental questions:
What constitutes a behavioral model?
How can we find behavioral models in the model space and propagate their predictions into the output
space while considering other uncertainties?
What is an appropriate framework for evaluation and comparison of models, methods and data within PUB? & Planning of future experiments.
These three questions will therefore be used to guide the discussion and structure the workshop. The pre-workshop experiment will be used to provide initial results to discuss.
