Just like last year, I had the opportunity and time to visit
the European Geosciences Union General Assembly 2016. There were several sessions on subjects related to the cryosphere and remote sensing, but most of the interesting Arctic sea ice-related stuff was happening on Thursday.
So, that's when I went to Vienna.
The day started quite strongly with a press conference called Sea ice decline in the Arctic. Dr. Alexandra Jahn from the University of Colorado talked about models and internal climate variability and Dr. Dobrynin from Uni Hamburg talked about how - as the Arctic loses more sea ice - there will be more, bigger waves eroding coasts and shallow seabeds, etc. This was all very interesting and how I expected a scientific press conference to be: about research looking at the past or the future, based on a painstaking and time-consuming process that involves lots of hypothesizing and data crunching.
However, to my surprise, yet another speaker was talking about the things we like to talk about here and on the Arctic Sea Ice Forum, things that are happening now, things that affect the melting season. Dr. Marcel Nicolaus from the Alfred Wegener Institute explained how a very warm winter resulted in less ice growth (check this previous blog post called CryoSat-2 confirms: sea ice volume is low), and as a consequence this melting season could be seeing new record lows. Depending on the weather, of course.
Robert McSweeney from Carbon Brief asked Dr. Nicolaus and several other scientists about their views on this:
So, that was pretty cool. After the press conference I had time to upload a few images to the ASIF and then went on my way to visit the oral session called Rapid changes in sea ice: processes and implications.
The session consisted of various interesting presentations.
Here's an overview:
Christopher Horvat from Harvard University talked about the Effects of the sea ice floe size distribution on ocean eddies and sea ice melting. Intuitively we all know that smaller ice floes will melt faster than a big one. Sea ice models have this cut-off size of 30 m, below which size is assumed to affect the rate of sea ice volume loss.
Horvat's PowerPoint presentation contained some really cool animations (the animated GIF above shows a part of one of them) of simulations that show how this works in theory. His conclusion is that ocean eddies and floe-edge circulation probably influence sea ice volume loss for floes that measure up to 100 km (much larger than the assumed 30 m). Read more about it on Horvat's website and his paper (under review at Geophysical Research Letters).
Up next was Anja Rösel from the Norwegian Polar Institute who talked about the State of Arctic sea ice north of Svalbard during N-ICE2015. Ice and snow thickness results from the N-ICE2015 cruise produced some interesting data, although Rösel told me later during the poster session that the winter observations were a bit boring because that series of Atlantic cyclones during the 2015/2016 winter dumped so much insulating snow on the ice that the latter hardly grew (just 15 cm in 2 months).
Unfortunately there isn't a lot of data to compare these results to, but the main goal of the expedition, of course, was to compare these ground measurements with airborne and satellite observations. Marcel Nicolaus also had a presentation on snow depth on Arctic (and Antarctic) sea ice, based on buoy data. Both Rösel and Nicolaus told me that practically the only historical snow depth data there is, is the Warren data set based on data from Soviet drifting stations on multiyear Arctic sea ice from 1954-1991 (here's the 1998 paper).
Rösel's name was familiar to me as she had done some very interesting PhD work on melt ponds using MODIS satellite images a couple of years ago (which I wrote about here). To my astonishment this important work wasn't continued due to a lack of funding, even though it shouldn't be too expensive to do, as the satellite images are already there for everyone to see.
My astonishment became even greater when I realized how important an assessment of the distribution of melt ponds during Spring can be to forecast the minimum. All we have right now, is the excellent model work done by David Schröder (see below), but it would be great to have observation-based data as well.
I managed to have a quick chat with Rösel during the break, and practically begged her to continue this important work. She told me that she was trying to get funding, as she had several ideas to expand the research and work together with other scientists who are doing similar research.
During the break, I was also lucky to be able to talk for almost half an hour with Dr. Florence Fetterer from the NSIDC. Recently I had been in contact with her about some other matters and when I saw she would attend the EGU general Assembly this year (unfortunately her presentation was scheduled for the next day), I asked her if she would tell me more about some recent work she's been doing on historical reconstructions of Arctic sea ice cover.
These reconstructions are a fascinating line of cryospheric research, in which various sources of information - satellite data, early monitoring, anecdotal evidence such as logbooks from whaling ships, etc - are pieced together to give an idea of what the Arctic sea ice pack looked like in the past. Back in January I wrote a blog post on reconstruction work that was done by fellow blogger Diablobanquisa (be sure to read the fascinating exchange in the comments with Rob Dekker), and I hope to do one on the work Dr. Fetterer has done with Walsh and Chapman, as soon as it is published later this year.
After the break the session continued with some tipping point stuff from Till J. W. Wagner, a Post-Doc at the Scripps Institution of Oceanography.
A paper he wrote last year with the same co-author, Ian Eisenman, about how Arctic sea ice loss doesn't lead to a tipping point and is thus reversible, received quite some traction in the media (I wrote about it here).
The stuff in this presentation called False alarms: How early warning signals falsely predict abrupt sea ice loss was way over my head (not that it takes much). I though about asking whether this means there is no reliable warning signal or that there is no tipping point, but I'm glad I didn't. You don't want to remove all doubt.
This was then followed by a presentation I was looking forward to: Spring melt ponds drive Arctic September ice at past, present and future climates in coupled climate simulation. The work that David Schröder from the University of Reading has done on modelling melt ponds, has featured quite heavily on this blog in the last two years, as Dr. Schröder has been kind enough to share melt pond distribution maps from his model which gave us an excellent insight into the build-up of melting momentum (see here for an explanation).
I think it's quite exceptional to receive that kind of info from a publishing scientist, and I was hoping to thank David again in person during the poster session. Unfortunately he was ill and left the congress centre after his presentation, but I was able to have short chat with Daniel Feltham, CPOM Professor of Climate Process Physics in Reading and leader of the group Dr.Schöder is a part of. He told me that their work on melt pond modelling was even more promising than they had initially thought and it might prove very useful for GCMs to forecast future Arctic sea ice loss.
One other person I had hoped to have a chat with, was Dr. Wieslaw Maslowski from the Naval Postgraduate School, quite well-known for his modelled projections of an ice-free Arctic in 2016 ± 3 years (see here and here). I wanted to ask how he viewed his model projection (especially this year, given the warm winter and subsequent events), but as he was busy talking to someone else after the oral presentation session ended, I figured I'd get an opportunity during the poster session. But alas, he didn't show up there. I guess I'd make a really bad paparazzi.
This was fully compensated, though, by the opportunity to meet Dr. Julienne Stroeve from the NSIDC, as I had been in contact with her a couple of times through the years. She immediately started telling me about the problems with the SSMIS sensor on the DMSP F17 satellite that have caused quite a few graphs and maps to go haywire since mid-April. I hope to write an in-depth article about that later this month.
The last chat I had at the poster session was perhaps one of the most interesting. Dr. Monica Ionita-Scholz from the Alfred Wegener Institute had already rolled up her poster and was about to leave, but was still kind enough to quickly explain her work to me (and even unrolled the poster again!) on the effects of Arctic sea ice loss in the Barentsz-Kara region on European winter weather:
The cold winters over Europe (low sea ice years) are associated with anomalous anticyclone and the downstream development of a mid-latitude trough, which in turn favours the advection of cold air from the north, providing favourable conditions for severe winters over Europe. We suggest that these results can help to improve the seasonal predictions of winter extreme events over Europe.
Of course, extremely low sea ice levels in the Barentsz and Kara Seas has become a regular feature now, and we did see some extreme cold weather in Europe during recent winters (2013 and 2014 come to mind). The past winter didn't see that much extreme cold in Europe, and Dr. Ionita-Scholz agreed the effect may have been trumped by the extremely high global temperatures, due to AGW fuelled by a strong El Niño. It will be 'interesting' to see what the effect of low sea ice conditions will have in the next few winters, and if increased scientific scrutiny will lead to incontrovertible evidence of a direct AGW fingerprint.
Just like last year it was a very exciting experience to get so close to science and scientists, and learn things that help me write this blog and make some of the science available to a wider audience. I'd like to thank the European Geosciences Union for providing me with a press pass.