Innovation is the cornerstone of Reuniwatt’s strategy, which is why we engage on many R&D Partnerships. But there’s also hands-on research happening within our company!

Research increases forecast accuracy

In a joint research project of Reuniwatt and Université de La Réunion, Dr. Frederik Kurzrock recently obtained his PhD in atmospheric physics at HQ location Reunion Island.
His dissertation “Geostationary satellite data assimilation with limited-area models for tropical solar irradiance forecasting” focused on the assimilation of geostationary satellite observations using a regional-scale numerical weather prediction model, leading to improved solar irradiance forecasts.

Achieving higher forecast accuracy is particularly challenging in the case of tropical islands due to pronounced convection and local thermal circulations. The assimilation of geostationary meteorological satellite observations can achieve improvements.
In his thesis, Frederik reviewed various existing approaches that aim at determining the atmospheric state with a focus on clouds using limited-area models, leading to a review paper that is available here. The review of the state of the art allowed Frederik to apply one of the most promising approaches to the southwestern Indian Ocean. Using the Weather Research and Forecasting (WRF) model, he assimilated cloud water path retrievals from NASA Langley’s SatCORPS cloud products with an ensemble Kalman filter (EnKF).

Kalman filters can be used to produce estimates of the atmospheric state, the so-called “analyses”. The ensemble forecasting approach allows to estimate the model error for a given time. A 41-member ensemble at 12 km grid spacing was used, and the EnKF of the Data Assimilation and Research Testbed (DART) was applied to assimilate gridded cloud water retrievals in the ice, supercooled liquid, and liquid phase. The effect on forecasts of the global horizontal irradiance (GHI) was assessed using pyranometer observations on Reunion Island in austral summer 2017/2018.
In his work, Frederik found a distinct positive impact of the applied method on the first 14 hours of GHI forecasts, and analysed the most important aspects of the forecast improvement due to DA. The method offers a portable and globally applicable approach that may also be applied to other regions of the Earth.

Frederik sums up his experiences during the PhD at Reuniwatt:
“The assimilation of geostationary satellite observations with high-resolution limited-area models is still a rather young field of research. On the one hand, I really enjoyed working on this fundamental research topic as a PhD student at Université de La Réunion – a strategic outpost of European research. On the other hand, I am proud to be part of the team of a dynamic company that develops innovative solutions to boost the transition towards renewables and that is not deterred from doing important fundamental research.”

Our R&D team is the catalyst for our technological advances. At Reuniwatt, we strive to implement original thinking in the technical field to improve existing products and develop the next generation of unique offers for our customers, and enable our team members to use their creative potential.

If you are a meteorologist or engineer working in a related field and you interested in our research, you can follow us on ResearchGate or LinkedIn, or contact us directly.

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About Reuniwatt (
Reuniwatt is a major player of the solar radiation and cloud cover assessment and forecasting. Based on solid Research and Development works, the company offers reliable products and services intended for professionals of various fields, making the best out of two key facets of the meteorology: atmospheric physics and data sciences. A particular focus has been placed on solar energy forecasting, while developing cutting edge solutions to improve the short-term prediction of the solar resource.
The company has won many grants, including H2020’s SME Phase 1 programme, which makes Reuniwatt a European Champion with regard to innovation.