Friday 14^th March

Whale Songs

Weather Outlook: The cold air outbreak is starting – looks good for polar low activity this weekend

Flight plan for tomorrow: Two flights in the Svalbard area, mapping heat fluxes and cold-air outbreak conditions

Blog

Today has been a busy day! Our PR guy Christian departed for Oslo and his Easter break, leaving me not only to write the weblog for the IPY-THORPEX site but also to publish it and Gudmund’s daily update on the website. Oh, the pressure. Both blogs can be found on the English-language part of our official project website: http://www.ipy-thorpex.no/Thorpex/English/ under Andøya 2008 campaign -> Gudmund’s log and also Emma and Ivan’s blog. My co-writer Ivan has already departed for a hunting trip, so for the last few days of the campaign it’s really Emma’s blog, and is just a copy of what I write on here. Gudmund’s daily updates are great fun to read, but unfortunately for you (and fortunately for us poor subjects!) you don’t get to see the accompanying photos of the day, complete with amusing captions. As I write this Gudmund is using Torsten as a model to get photos of the campaign t-shirt; the photos will surely accompany the next update!

Today we did a lot of outreach. Øyvind Sætra from Met Norway gave a short lecture first to the air base staff, then the staff at the weather station, and then to the staff at the rocket range where we are staying. The latter also gave us a presentation of what they do at the rocket range, which was interesting. After that we had a few hours off to go whale watching. It’s not the tourist season yet, but Gudmund managed to persuade the owner of the Andenes Whale Safari to take us out, because the weather was good and the seas quite calm for the time of year. We were all wrapped-up wearing as many layers of clothes as was practical because although it was about 3degC today, the wind on the sea made it feel a lot colder. We sailed out from Andenes to the edge of the continental shelf, where the water deepens and the whales spend their time feeding on octopus. It took an hour to sail there and we quickly spotted our first whales on the horizon. We were really lucky to spend the following hour watching one whale after another. They were sperm whales, which are pretty big! You can spot them on the horizon by the jets of spray that they eject (I don’t know the technical term). Even though they’re huge they’re so graceful. Our crew were experienced at watching these creatures and would shout ‘diving’ just before they dived down into the deep, giving all the photographers among us time to position our cameras for that perfect shot of the whale’s tail. By the time we returned the sun was setting, and we were all starting to lose the feeling in our fingers and toes. Fortunately there was a warm dinner waiting for us at the rocket range – not whale thankfully – of Pollack au gratin with salad and boiled potatoes.

Tonight we have to do the flight planning for tomorrow. Gudmund’s offer to drive people to the local rock concert “Rock Mot Rus” (Rock against intoxication; it’s an event for regional schoolchildren where local rock bands play as well as some big Norwegian rock bands) is proving less tempting than a night looking at forecast charts. The consensus for the flights tomorrow seems to be studying the heat fluxes north of Svalbard, also mapping the conditions that polar lows might form in tomorrow or Sunday.

Weather Round-up

The forecasts of polar low activity this weekend are still varying between model and forecast base time. What the models do agree upon is the cold air outbreak. The cold air outbreak is starting today, but confined to the west coast of Greenland and down over Iceland. The air is coming from the Svalbard area, and is being advected southwards on the western flank of a large area of low pressure centred over Scandinavia. Through Saturday the low pressure region starts moving away east, and the isobars show the air coming from over the pole all the way down to the UK on Sunday. Embedded in this flow are several troughs, which appear and disappear within 12hrs. This indicates the potential for polar low development, and the satellite images will be closely monitored to for indications that these troughs are in fact polar lows.

We only have PV as a diagnostic from the HIRLAM model not the ECMWF model. The HIRLAM model shows an upper-level PV anomaly extending down into the Norwegian sea, west of the coast of Norway on Sunday. This comes from Greenland, and on Saturday advects first east and then southm extending in a tongue parallel to the coast on Sunday. The wind field at 300hPa shows a jet streak moving up from SW of Greenland, over Greenland and then moving south with the PV anomaly, with 90kt winds. The PV anomaly is directly above the cold air which has been advected off the ice sheet N of Svalbard. This could provide the upper-level forcing necessary for polar low formation. The difference in sea-surface temperature and 500hPa temperature is increasing over the weekend. By Sunday it reaches the threshold of 43⁰C, west of Andenes. This is used by forecasters at Tromsø to help them forecast polar lows – nearly all polar lows form after this threshold is reached and few are seen to form below this threshold.

SAP Evaluation

The ETKF SAPs show the sensitive region to the north of Andøya, around Svalbard. For longer optimization times this region extends further west, closer to Greenland. This makes sense because the cold air outbreak is developing there, and it is this region that the polar lows are likely to form in.

The SV SAPs for 12hrs optimization have the region of maximum sensitivity over the UK, on the north-west side of a low pressure system. For 24hrs optimization a region midway up the Norwegian coast is indicated, stretching out into the Norwegian sea. There is weak upper-level flow into the verification region from here. The SAPs for 36hrs optimization look similar.