Reanalysis Matters

Next week, I will be participating to the Sixth WCRP International Conference on Reanalysis (ICR6) in Tokyo and presenting the work achieved so far as part of the TEM#111 Initiative (on the 30th). There, I look forward to meet with Jacob Tornfeldt S?rensen from DHI, and I presume many other Wind Energy practitioners.

The reanalysis community meets all at once very rarely. The ICR6 is the 6th conference of a cycle started in 1997, and 7 years (!) have passed since the ICR5 in Rome.

• ICR1 (1997) https://opencat.library.ucar.edu/cgi-bin/koha/opac-detail.pl?biblionumber=48068
• ICR2 (1999) https://opencat.library.ucar.edu/cgi-bin/koha/opac-detail.pl?biblionumber=49954
• ICR3 (2008): https://jra.kishou.go.jp/3rac_en.html
• ICR4 (2012): https://reanalyses.org/meetings/4th-wcrp-international-conference-reanalyses
• ICR5 (2017): https://climate.copernicus.eu/5th-international-conference-reanalysis

Picture credits: Asako Narahashi, Kawaguchiko #6, 2003

Reanalysis Matters for Wind Energy

I remember very well attending online part of the ICR5 and Gil Lizcano 's presentation, and Michael Bosilovich suprise reaction on Gil's statement about the all-time famous 50m wind being the workhorse of the industry for long-term correction ^^

Since then, much happened on the reanalyses fronts:

• ERA5, JRA-55
• Regional reanalyses over Europe (CERRA, COSMO, etc) and APAC (BARRA, NZRA)
• Various downscalings of ERA5 (NORA3, NEWA, GWA, ...)
• next GEFS and MERRA-3 in planning

But not so much happened on the dialog between the two communities:

• Do we (wind) and them (reanalyses folks) know each other personnally, meet in conferences?
• Do we know what the work for doing (curent and future) reanalysis entails?
• Do they know how important and crucial these data have become?
• How can we support each other, and make sure we continue to benefit from reanalyses in the future?

Apart from the 2017 AWEA letter of support to MERRA-2, only a few sporadic interactions took place; and this status-quo situation led me and a small group of practitioners and researchers to organise the IEA Topical Expert Meeting #111 at DTU, last spring. The TEM#111 intiative aims to:

• Improve access and documentation of reanalysis datasets.
• Promote and foster validation and advertise successful applications of reanalysis datasets for Wind Energy applications, and thereby improve their value.
• Act as a point of contact / collaboration forum between reanalysis providers and the Wind Energy communities.

One of the success of the TEM was to gather all parties in one room, so contacts could be established and detailed discussions take place. Of course, we're not finished discussing, and this is why myself and Jacob join the ICR6 this year, but already now can we feel the benefits of having created a formal interface between ourselves, via the IEA Wind TCP:

• We have been involved in the ERA6, and NOAA GEFS users workshop consultations.
• We have begun testing ERA6 (see the second issue of the TEM newsletter).
• We have clearly communicated to the reanalysis community the list of high-quality publicly available measurements for validation work.
• Above all: we have a established a small network of people actually doing reanalysis and wind/power grid projects for a living (and not only high-level executives, or program managers).

Another key take-away from the TEM#111, is that the reanalysis community cannot only address wind-specific suggestions, comments and projects. Maybe are we the best placed to provide feedback, but this discussion needs to take place at a higher, sectorial level.

This is the reason why, together with Energy Meterologist Justin Sharp and others from the wider power-grid / utilities practioners community, we are slowly settling into a "beyond-wind" framework, where improving reanalyses will take place not only from the sole perspective of Wind Energy. This is work in progress, and more news are to be expected on this soon.

Reanalysis Matters. Period.

With the growing dependence of our infrastructure to climate- and weather stochasticity and long-term changes, reanalyses matter today and will continue to matter in the future.

The better we know these datasets, what modelling systems have been used for producing them, their inputs, their know biases, etc, the better we are prepared to de-risk future infrastructure projects.

Question: how to do AI weather forecasting, without a supercomputer? Answer: start with producing a reanalysis with a super computer....

During the ICR6, let us celebrate Reanalyses

During the ICR6, I will regularly be posting about relevant / fun and interesting findings from the event. I will do so using my Reanalysis Appreciation Week 2024 account, to not spam everyone... but only those interested in celebrating these marves og science and engineering that are reanalyses !

Feel free to share your experience with reanalyses, your expectations and your questions during that week using the hashtag #reanalysis2024. I will do my best to repost, forward them and put you in touch with the right people.

Long live reanalysis!