As part of the nextGEMS production stage for our high-resolution Earth system simulations, a new hackathon edition has been launched. The fifth nextGEMS hackathon is currently taking place in the central Netherlands, in the city of Wageningen, renowned for its university and vibrant student life.
From October 14th to 18th, 2024, more than 80 scientists, researchers, students, and other representatives from across Europe, North America and East Asia gather for the „Hazard Hackathon“ at Wageningen University. Here, they can collaborate, network, and tackle pressing challenges related to fire weather, precipitation, urban heat extremes, and more.
On the first day, Chiel Van Heerwaarden, a researcher and co-organizer from Wageningen University, kicked off the event with a welcoming speech and general information for the week to come. Following, scientists Dyvia Praturi from the Max Planck Institute for Meteorology and Xabier Pedruzo from the European Centre for Medium-Range Weather Forecasts (ECMWF) provided updates on the available ICON and IFS Earth system models‘ simulations.
Praturi encouraged participants to seek guidance and answers to their questions about the Easy Gems platform, while Pedruzo highlighted a recently published research paper detailing the advancements in IFS simulations.
During the opening session, Jasper Denissen from ECMWF introduced the audience to the Catchment-based Macro-scale Floodplain (Ca-Ma-Flood) model. He explained how its hydrological forecasts are being used in nextGEMS simulations and mentioned some of the Ca-Ma-Flood output variables that participants can work with, such as river discharge and flooded fractions.
Before the first day concluded with an exciting ice-breaker session that included some delicious local finger food and a round of pool and table tennis, Edgar Dolores-Testillos from the University of Bern presented the innovative structure of this hackathon. Unlike in the previous events, this time participants will have the opportunity to choose from five defined challenges: efficient data handling, fire weather, precipitation and temperature extremes and urban heat, energy production, and a „wild card“ challenge encompassing topics like tropical cyclones and extreme precipitation. Nevertheless, he emphasized that participants are also free to pursue their own or collective interests during the upcoming days of the hacking marathon.
by Thorsten Mauritsen, MISU
By directly and more physically simulating specific events (e.g., tropical cyclones, rainfall extremes, blockings) most associated with hazards, nextGEMS provides an improved basis for assessing risk globally. The importance of simulating fine scales for assessing hazards, but also for other applications, is well understood and motivates the patchwork of downscaling approaches known as the value chain. A Challenge Problem, co-defined with stakeholder groups, hereby, will help guide the development of the SR-ESMs, and their associated workflows, in ways that better expose their information content to application communities. This will allow us to “short-circuit” the value chain and develop a new model of Integrated Assessment. Activities are planned in the form of pilot projects on near surface (wind/solar) renewable energy, marine productivity, and changing weather or climate related hazards.
For the challenge problem in the renewable energy sector, we addressed specific challenges:
Challenge 1: What is the minimal amount of information needed to optimize the design of a regional renewable energy system and how can we extract this information from global storm-resolving models.
Challenge 2: How does the potential renewable energy output landscape change with a changing climate?
During the Cycle 2 Hackathon our stipends were provided with meteogram station data from two different models. Along with temporally sparse snapshots of full three dimensional model output. The main goal was to either find a condensation of the high-frequency output or suggest other output variables, to support the design of renewable energy systems.
Support was given by technical consultants (members of the modelling groups) to help them understand the model output and ways of accessing it since the focus shall lay on the science rather than solving technical problems.
Additionally, the teams were supported by energy consultants, to for instance help them understand design parameters (hub height, diffuse versus direct efficiency, etc.). In particular we had two sessions with Iberdrola and with Vestas Wind Systems. These sessions were particularly useful for the participants to understand the problems that the energy industry is facing, and provided an opportunity to discuss their results with experts. There was also a discussion of how the participants potentially develop a carreer in the renewable energy sector.
The approach taken in the Hackathon is to use the ability of the nextGEMS models to resolve the mesoscales and represent relevant motion and fields for renewable energy production. We used primarily dedicated high frequency output for a series of stations, but also the complete mapped output.
For example the wind at rotor height of a typical wind power plant around 100 m above ground is used directly to calculate the power output from a typical turbine. Figure 1 shows how the output depends on the wind speed. The output starts at a minimum wind speed and increases with the wind speed to the third power up to a maximum value which is limited by the generator size. At high wind speeds the turbines automatically turn off to limit wear and for safety reasons.
Because the power output curve is highly non-linear in the wind speed, we were interested in seeing how much estimated power is biased if using lower temporal resolution. Figure 2 shows output for four different stations. First we note that estimated output is monotonically decreasing with lower resolution suggesting that all stations, except perhaps the EURECA ocean site, are mostly seeing winds on the qubic wind speed range. For this a different combination of turbine, generator and tower height can be used to extract more energy at these sites. We also see that the bias is very low when degrading from 3 minute to 1 hour means, and even monthly mean wind speeds provide a reasonable estimate. Here it is important to note that this is the average of the instaneous wind speed. If the wind components were average the degradation would be much larger.
We checked how the models perform in terms of representing the observed wind speed at the flat surface Cabauw site in the Netherlands. It turns out that both the IFS and ICON grossly underestimates the occurrence of high wind speeds.
This bias in both the IFS and the standard ICON-Sapphire setup is related to the parameterisation of turbulent drag. This can be seen from the 10 km resolution test simulation conducted using the TTE scheme, which exhibits a more realistic distribution at Cabauw (see figure 3).
Figure 4 shows a comparison of the monthly mean modelled downwelling shortwave radiation with observations at the Cabauw site. Here both IFS and ICON do a good job in predicting the observations. Also, the IFS model was analysed in three different resolutions but there is no obvious difference.
To convert the downwelling shortwave radiation to power output one must take into account various losses, here assumed to amount to 12 percent, as well as the temperature degradation, here assumed to be -0.5 %/K (see Figure 5.)
What became clear through the Hackathon was that the wind industry is already working with quite advanced modelling tools for site planning and short term forecasting of wind power, along with on site observations. The situation is slightly less advanced for solar power, partly because the modelling tools are not nearly of the same quality due to problems with modelling clouds. New demands on the industry to also assess the impact of the changing climate on production, safety and durability/maintenance needs is a challenge that the industry is not well suited to meet, and where more research is urgently needed. Also, industry is looking forward to leveraging DestinationEarth digital twin simulations in their workflow.