by Aslihan Ural

Together, we brainstormed and came up with promising strategies for model intercomparisons using the ISIMIP protocol. This includes water quality intercomparisons across scales, sectors, pollutants and scenarios. We would like to build on the strengths of our models to identify robust water pollutant hotspots, their sources and trends over time. And the ISIMIP protocol can help us to make next steps towards the harmonization of model inputs to be able to contribute to cross-sectoral assessments. In a meantime, the water quality community can take a faster track and compare water pollution, hotspots and trends using simulations that we already have from our water quality models. This is a great warm-up of our joint water quality journey and will also give input to our next workshop on paper ideas (to be planned in spring 2024).

We had a wonderful time! Model experts were challenged to solve a puzzle on the ISIMIP aspects. The room was full of discussions with a lot of enthusiasm. It was great to see. The important outcomes of the workshop are that we identified four main directions to focus on:

1. model intercomparison approaches,
2. robustness of pollution hotspots, sources and trends,
3. cross-scale comparisons, and
4. model inputs/harmonization.

These are essential directions to make the next steps towards the ISIMIP protocol and joint model intercomparison assessments. If you're interested in reading more about the workshop please see below.

We would like to thank the ISIMIP and PROCLIAS for supporting this workshop. It is an important platform for water quality modelers to interact, share experiences and create new ideas and comparisons. Special thanks go to the whole water quality community for their active participation, and to the organizers of this workshop. See more photos here.

We conducted two half-day workshop to contribute to a draft protocol on global water quality models and model intercomparisons. The first day started with a presentation on the updates for water quality protocol on two directions “Fast track” and “ISIMIP 3b” for model intercomparisons and summary of the two ISIMIP 3b protocols. Then, we had brainstorming and discussion sessions on model overviews and strategies for model intercomparisons (e.g., cross-scale, cross-sectoral, hotspots, trends, processes) by using the protocols. The opportunities (e.g., interaction between modelers) and challenges (e.g., diversity and complexity of the models, harmonizing the model inputs) were mentioned in the plenary. Attendants agreed that model intercomparison should be relevant to e.g., Sustainable Development Goals, policies, Green Deal, etc. The first day is ended with a demonstration on how to submit simulations to ISIMIP and a networking dinner.

In day 2, we had brainstorming and discussion sessions on identifying collaboration topics across sectors and scales for model intercomparisons based on the previous discussions. The main focus was on how to proceed with the “Fast track”. We identified four main topics that will be the basis for the next steps in the “Fast track” and will serve as input to a paper writing workshop in 2024. Two promising directions for model intercomparison were identified as “Qualitatively-based (integration)” (e.g., using indicators or other approaches to compare hotspots, sources and trends across pollutants and scenarios) and “Quantitatively-based (intercomparison)” (e.g., comparing pollution levels by two model simulations for one water quality constituent.). The workshop is ended with concluding remarks and announcement of the next steps.