The fourth day of the EGU 2019 was the day of seasonal prediction. To be more exact the session was named subseasonal to seasonal (S2S) and it covered a wide range of topics within this field. It started in the morning with a session on mechanisms and ranged from large scale atmospheric patterns to ocean variables.
The second session focused on predictability and showed several examples of variables which are predictable from a few weeks to a few month in advance. In the final presentation session the topic switched to applications and showed some use of the prediction for the energy and agricultural sector.
In this section I have also given a talk on multi-model subsampling. It was not really my talk, as I was just taking over from someone who was not able to make it to the conference this year on short notice. Anyway, it went quite alright. The day ended with the posters of this session, which offered a good mix for all of the topics above. Tomorrow I will have my own poster in the final session of the conference.
The third day of the EGU this year saw a change in weather. Instead of the well loved sunny Vienna spring days, the next few days will show us their grey and rainy side. Anyway, it was also a day which was not so overwhelmingly filled with interesting talks, so I used it more for meeting people.
It started in the morning with a splinter meeting on sea-level databases. A small group had a lively discussion on creating the future of databases in this field and it was fun to see what might happen here in the future. After that I had some talks with people on future projects and visited a few talks on ice sheets in Antarctica and Greenland.
The rest of the day I mainly visited the poster halls and in between watched a medal lecture on astronomical cycles. As there was no session of real interest for me left for the last slot (and if it was, I guessed I wouldn’t have fit into the room anyway) I called it a early days end. An EGU day without sun is quite different than with it. Usually everybody leaves the centre for lunch to have a picnic in the park, but with all the rainy intervals, everybody looked for a place inside the conference centre. As this might be repeated for the rest of the days, the EGU this year will have a completely different character than the last ones I visited. Let’s hope for the best. Tomorrow will be my talk and it will be certainly dominated by seasonal prediction.
Day two of EGU 2019 and as always it was a busy day. My program started today with a session on climate prediction. It was interesting to see different approaches to similar problems. Especially when you see in successive talks similar physical mechanisms described from different perspective, but explained completely differently. A chat between some authors would then certainly bring solutions to all groups, but I am sure some will not even have recognised the similarities.
The second session covered the North Atlantic. Like so many sessions here in Vienna this year the room where more than packed. The talks covered many different aspects, mainly on the thermodynamics. I left half-way, as I wanted to see some posters, which were mainly on statistics.
After lunch I enjoyed the medal lecture by Shaun Lovejoy, who gave an interesting overview of the different scaling mechanisms in the atmosphere and the competition between random and deterministic approaches. The rest of the day was again visiting posters, trying to make my way into sessions (and failing) and finally sitting in the back of a statistics session to relax a bit.
Today I heard from several people that they got annoyed from the overfull rooms. You hear this complain every year at EGU, but it seems to get louder at the 2019 edition. Or maybe, the sessions I visit (and those of the people I talk to) just got a bit more popular this year compared to the years before.
It is 2019 and it is spring time in Vienna again. The night train from Hamburg to Vienna was as always a great experience and so the conference was set up for a good start. The sun is giving everybody a big smile (at least for the start) and so and eventful week lies ahead of us.
The first day was fully covered for me by sea level science. The sea level session covered as always a wide range of topics. From reconstructions over land movements, from GIA to the political site of the problem. Unfortunately, my favorite topic, the palaeo-reconstructions were only covered by a very small number of talks (probably just one).
I have also to get used to the new schedule of seven talks per session, but I will certainly write about it more later this week. I also went to a poster session, which are now in parallel to the talk-sessions. So a lot of changes, which all need some adaptions.
During the week I will have a talk and a poster, but both will happen towards the end. I am looking forward for many interesting topics, talks and posters and of course the most important part of a conference: meeting other scientists.
A new year has started and in the recent month three new papers have been published, which have my name in the author list. In all three cases my contributions were more in the sense of statistical assistance, so I will just briefly introduce the topics.
Skilful Seasonal Prediction of Ocean Surface Waves in the Atlantic Ocean
This paper predicts ocean surface waves on the seasonal scale. It uses enhanced prediction of the NAO with the sub-sampling algorithm to generate prediction skill for wave height in the North Atlantic. As the prediction enhances not only wind waves, but also the swell it is a consistent prediction enhancement for the total wave height.
Dobrynin, M.; Kleine, T.; Düsterhus, A.; Baehr, J: Skilful Seasonal Prediction of Ocean Surface Waves in the Atlantic Ocean, GRL, 46, 1731–1739
Seasonal predictability of European summer climate re-assessed
The second paper investigates the predictability of European summer climate by a physics-based sub-sampling. It uses for this a connection from tropical Atlantic SST anomalies over a wave train in the upper troposphere to the second mode of North Atlantic surface pressure. Unlike European winter’s, the second mode is as important as the first mode for European summer climate. As a consequence the predictability of surface temperature and other atmospheric variables over Europe are enhanced.
Neddermann, N.-C.; Müller, W. A.; Dobrynin, M.; Düsterhus, A.; Baehr, J. (2019): Seasonal predictability of European summer climate re-assessed, Climate Dynamics
Atlantic Inflow to the North Sea Modulated by the Subpolar Gyre in a Historical Simulation With MPI‐ESM
This study uses a global model to show that the strength of the subpolar gyre (SPG) has a profound influence on North Sea water properties. Up to now regional models showed that most of the modulation happens due to Atmospheric influence. The modulations by the SPG happen on a decadal scale and can be followed on their way from the Atlantic to the North Sea.
Koul V.; Schrum, C.; Düsterhus, A.; Baehr, J.: Atlantic Inflow to the North Sea Modulated by the Subpolar Gyre in a Historical Simulation With MPI‐ESM, JGR Oceans
Just after I have attended a conference on seasonal and decadal prediction at NCAR in Boulder/Colorado, my next stop was at the PALSEA and QUIGS meeting in Galloway/New Jersey. It was the third time that I attended a PALSEA and as the other two times it was a great opportunity for me. The main topic of the conference was the sea-level and climate change during the last and other interglacials.
Many talks surrounded the available data and their interpretation. In this context it is a very complex task to bring together on the one side the many different proxies and evidences of sea-level height during that period and on the other side to explain their causes by the changes of ice-sheets in the higher latitudes and the reaction on them by the Earth. As a consequence there were many interesting discussions surrounding this field and many different viewpoints were heard. Specific questions around when the last interglacial exactly started, how high the sea-level was during that period and how the exact evolution of sea-level happened during that time were often discussed during this week. Most discussions were evidence driven, trying to make sense of the sometimes contradicting results and their uncertainties.
Also the understanding of the consequences of these results played an important role, as sea-level change is not happening isolated. It requires the build up or melting of ice shoot and with it a change in climate. In a climate system, as we know from looking around us today, that is highly connected all the climate sub-components, especially atmosphere, cryosphere and ocean have to tell the same story.
Myself have presented a poster on the last interglacial sea-level evolution and had several interesting discussions on this topic. Also the field trip, which showed us the study fields of salt marches, which are used to investigate Holocene sea-level change at the East American coast was very informative. Seeing the data collection first hand always helps to understand the topic better and getting better results at the computer in your own office. All in all it was a great opportunity for me, which was made possible by the financial contribution by the organisers, which allowed me to attend.
Last week NCAR in Boulder (Colorado) hosted the second edition of the International Conference on Subseasonal to Decadal prediction. It covered the climate prediction from a few weeks up to a few years and hosted with around 350 scientists a good representation of the community in this field. During most of the days the conferences was split into a subseasonal to seasonal (S2S) and a seasonal to decadal (S2D) session.
The International Conference on S2S2D poster
I personally visited only the S2D part, as my current work focuses on this topic. The first day looked into the mechanisms of predictability and the typical candidates, like ocean, soil moisture and stratosphere, were discussed. The second day shifted then more to the modelling of these phenomena. The weather services presented their new prediction systems and new approaches to modelling were discussed. As a third topic covered the handling of the predictions. It looked at calibration and other technique to make the prediction really useful. This lead to the fourth topic, which discussed the decision-making process basing on the prediction. Here, the applications were the main focus points and many different phenomena and their predictability were shown. Topic number five looked at the statistical verification. It presented new approaches to access the skill of the models. The final session of the S2D session looked at the frontiers of earth system prediction and therein especially at the handling of carbon within the models. Afterwards in a combined session of both parts many different aspects on the future of research in this field were brought up. Among others the topics of temporal dependence of forecast skill and the so-called ‘signal to noise paradox’ lead to a lively discussion.
My personal contributions were threefold. I showed on a poster in the first session how the Summer NAO can be predicted using ensemble sub-sampling. In the second session I presented a poster on the view that sub-sampling can be viewed as a post processing procedure and can so explain why it works. The talk in the fifth session then covered the 2D categorical EMD score.
All in all it was a great conference, with many interesting discussions and a great overview over this interesting field. Certainly many impulses will come from this and will give not only my own research a new push.