Conference: The Future of Cumulus Parameterization

The flights between Sydney and Paris gave Maxime a chance to observe convection from above.

by Maxime Colin
I got the chance to attend The Future of Cumulus Parametrisation Workshop held in Delft from July 10-14, which was co-hosted by ARCCSS and co-organised by Christian Jakob. And what a rare phenomenon! Having more than 100 scientists who love thinking about convective parameterisations gathering together in the same place, for an entire week, re-thinking the bases of convective parameterisations, discussing the best way to improve them in the future. I was incredibly lucky to get the chance to meet so many prominent convection experts and convective parameterisation developing teams. We had researchers coming from many areas of Europe, the US, Japan, Australia, India and more.  They also had different expertise: actually developing convective parameterisations; analysing convective processes in models in order to formulate better equations; or using different observation techniques to understand the physics of convection.


Maxime discussing science with Binta, a fellow PhD student at LMD, Paris.

I had the chance to give a talk on my PhD topic, the sources of convective memory, and to present a poster as well. I had some interesting feedback, with people questioning the scientific meaning behind our results and giving relevant remarks for the future of this study. Many developers were very interested in convective memory, so our work really seemed to be useful to this modelling community. At the end of the workshop, we voted for the most important topics to focus on in terms of research and parameterisation development over the next few years. Memory came out first (in a tie with stochasticity) out of six. It is incredibly exciting to see my PhD topic being considered by world-renowned experts as a leading theme for convection.

The conference was followed by a visit in Paris to meet with my two co-supervisors, Sandrine Bony and Jean-Yves Grandpeix. It was a short but intense week that I spent with them. We took as much as two full afternoons to discuss all the main results in my PhD, ranging from the high-resolutions simulations to the climate model improvements via the use of strong nudging to isolate some of the memory effects. Their questions and feedback was useful to deepen our thinking about convective memory, and to plan further analysis.

One of the main goals of my stay with my co-supervisors in Paris was to start up three analyses that I will perform with their climate model in the next few weeks. They are:

  • running some pseudo-homogenisation “restart” experiments to know where the convective memory of this climate model comes from;
  • preparing the Madden-Julian Oscillation analyses on climate runs we already had; and
  • finding some good observation-based maps of precipitation frequency.

It was very important to be with them, as it always takes time to run a climate model in a new way. Thanks to their guidelines, and debugging assistance, I could start up the new runs and get the new analyses ready for use. It is so valuable to collaborate with other people: you make progress so much faster, you learn new things in a very natural way, and you end up exchanging challenging ideas that directly feed on your own thinking.

Last but not least, the flights across the world from Australia to Europe and vice-versa were an amazing opportunity for me to look at the sky, from the sky! Or to be more precise, to admire the clouds directly from the best possible lookout. I had the chance to cross the Maritime Continent during daytime, and to fly over the Inter-Tropical Convergence Zone (one of the most cloudy areas in the world, just near the Equator). I saw impressive layers of clouds overlooking one another, and beautiful cloud cover over most of North-Eastern Europe. I got the chance to take great cloud pictures and even movies! That is also precious knowledge for the brains, and for the eyes.
 


Travelling home and who should Maxime meet at Amsterdam airport but David Webb.

The world from the sky is massive, but actually not too big for climate scientists. On my return from Europe to Australia, I had the astonishing surprise of meeting David Webb, a fellow CCRC and ARCCSS PhD student, who was also travelling back to Australia after a completely independent trip to Europe. What are the odds!

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