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Thanks Neven! ;-)
Toggle Commented Jan 8, 2018 on PIOMAS December 2017 at Arctic Sea Ice
Hi AJT, The answer to the question of why we currently have more arctic sea ice than a year ago is found in Neven's PIOMAS updates: The past few months have been colder (Read: Less anomalously warm) in the central Arctic region than they were a year ago during the extremely warm 2016/17 winter. Secondly, heavy snow fall on the sea ice caused by the frequent late fall/early winter storms a year ago further hindered sea ice build-up, while the past few months have seen a much higher degree of clear skies above the ice, enabling a more efficient heat exchange between water/ice and the atmosphere. In the next PIOMAS update I would expect still overall relatively high average sea ice thickness numbers, as area has remained low (Slow sea ice build-up in peripheral seas), while the sea ice volume is growing relatively well in the central Arctic seas.
Toggle Commented Jan 7, 2018 on PIOMAS December 2017 at Arctic Sea Ice
Fortunately, the Arctic sea ice is still faring better than a year ago with a slightly thicker sea ice pack: Sea ice area similar to last year and about 1400-1500km3 more sea ice in the pack.
Toggle Commented Jan 5, 2018 on PIOMAS December 2017 at Arctic Sea Ice
Warmer at the core of the high? I have noticed since yesterday that at the core of the high, the 2m temp is a few degrees higher than in the surrounding area: http://ocean.dmi.dk/arctic/weather/arcticweather.uk.php This seems counterintuitive, so I was wondering if the sensors are being tricked in this situation, or if anyone would know why the near ground temp at the core of a cold high should be higher than the surrounding area?
Toggle Commented Dec 15, 2017 on PIOMAS December 2017 at Arctic Sea Ice
Hi AJT, Here is how it works on Neven's blog: He will post an update on some topic; melting status, monthly PIOMAS, or a specific topic of interest. He then indicates an update to be the open thread like these monthly PIOMAS reviews, where you can stray from the topic of the update - as soon as you stay within the realm of everything Arctic sea ice/climate. I don't mind a few stray comments at all, and this is not my blog, but responded to your notion of an 'open forum', which is not the case for this blog.
Toggle Commented Dec 12, 2017 on PIOMAS December 2017 at Arctic Sea Ice
Regarding ice volume distribution: It seems like the fairly consistent high above the CAB/Laptev in recent weeks is starting to make an impact on ice volume distribution: http://polarportal.dk/en/havisen-i-arktis/nbsp/sea-ice-extent/ On the Siberian side of the CAB into northern parts of the ESS and Laptev, there seems to be nearly as much thick ice as in the safe haven north of the CAA, something I have not noticed since pre-2007. Given the overall low volume, the ice volume north of CAA must be showing a more significant negative anomaly. If the high continues as is still forecasted, the clockwise rotation of the main pack will pick up speed causing more ice to exit the Arctic via Fram in the coming one/two years - Fram export being also a main culprit of the massive sea ice loss in 1981-82, and contributing in 2007.
Toggle Commented Dec 11, 2017 on PIOMAS December 2017 at Arctic Sea Ice
Hi AJT, Neven's Arctic Sea Ice Blog has never been an open blog to discuss any topic of preference, so please respect that. You can stray for a comment or two, but otherwise need to get back on topic or take the discussion elsewhere.
Toggle Commented Dec 11, 2017 on PIOMAS December 2017 at Arctic Sea Ice
wayne, You wrote Nov. 17: "a very cold CAA CTNP will dominate weather as is for quite some time in the foreseeable future." I commented on Dec. 2, but that was too early, as you said: "wait for the projected time period ends before making a comment" However, in the forecast reaching mid-December I still see the circulation dominated with the Siberian high semi-connected with the high between the Pole and Laptev, so is the foreseeable currently ongoing or have we perhaps not reached it yet?? ;-)
Toggle Commented Dec 11, 2017 on PIOMAS November 2017 at Arctic Sea Ice
Thank you for another great update Neven - and Happy Holidays to you as well! At least it seems like the Alp region is having some early snow this year, but maybe not as far east, as where you live?
Toggle Commented Dec 7, 2017 on PIOMAS December 2017 at Arctic Sea Ice
Hi Kevin, Yes, but.. DMI has this to say about their 80N temp: "Plus 80N Temperatures - explanation. The temperature graphs are made from numerical weather prediction (NWP) "analysis" data. Analyses are the model fields used to start NWP models. They represent the statistically most likely state of the atmosphere, given the information available to make the analysis. Since the data are gridded, it is straight forward to deduce the average temperature North of 80 degree North. However, since the model is gridded in a regular 0.5 degree grid, the mean temperature values are strongly biased towards the temperature in the most northern part of the Arctic! Therefore, do NOT use this measure as an actual physical mean temperature of the arctic. The 'plus 80 North mean temperature' graphs can be used for comparing one year to an other." http://ocean.dmi.dk/arctic/documentation/arctic_mean_temp_data_explanation_newest.pdf
Toggle Commented Dec 6, 2017 on PIOMAS November 2017 at Arctic Sea Ice
Hi AJT, Regarding the DMI 80N temp, which I assume you are looking at: This measure is calculated as the average temperature for each degree of latitude between 80N and 90N. Consequently, the average temp of the 80N latitude has the same weight as the 89N latitude, although the latter covers only a tiny geographical area. The DMI 80N measure is therefore extremely sensitive to the temperature at the geographic Pole and not the CAB or the Arctic. DMI 80N temp is then useful only to compare across years and seasons, but is not providing a meaningful measure of the Arctic temperature. I referenced DMI 80N a few weeks ago since an anti-cyclone was moving to the geographic Pole, which therefore more significantly impacts this measure. Right now the anti-cyclone is closer to the Siberian side, so the cold is moved to the lower latitudes on this side, while the highest latitudes are relatively warmer: http://ocean.dmi.dk/arctic/weather/arcticweather.uk.php
Toggle Commented Dec 5, 2017 on PIOMAS November 2017 at Arctic Sea Ice
Arctic weather forecast for the coming week with impact on sea ice: The current low in the CAA will fade away, but then is set to reappear in 4-6 days, as moisture moves north across the US and fails to pass south of the Greenland high, which continues to block the moisture on its western side. With both the Greenland and Siberian highs seemingly fixed, the three lows (CAA, Barents Sea, and Bering Sea, and the high hovering over the Arctic sea ice (Semi-connected to the Siberian high) will remain. Central area of the ice will therefore be cold with the Beaufort Gyre picking up speed and further cooling down Hudson Bay, Sea of Okhotsk, while ice accumulation in Barents, Kara, Baffin, Bering will remain weak.
Toggle Commented Dec 2, 2017 on PIOMAS November 2017 at Arctic Sea Ice
Hi wayne, You wrote on your blog a couple of weeks ago, Nov. 17: "New state of the art refraction technique confirms Canadian Archipelago atmosphere set to dominate Global Circulation." And concluded: "At present, 2017-18 seems to tend going towards a very warm Euro-Asian Arctic winter, while CAA is coldest, we observe if the cut off of snow supplied from the North Atlantic by way of the the North Pole continues, if so, permafrost will freeze hard, sea ice will thicken more, a very cold CAA CTNP will dominate weather as is for quite some time in the foreseeable future." Two weeks later the CAA is unusually warm with areas as much as 15C or more above average temperatures, while central/eastern Siberia is considerably colder than normal: http://polarportal.dk/en/weather/ Now, if you hadn't used the condescending tone above I would have ignored this - as we all fail in our attempts to understand weather - but would you like to comment on how your approach has worked?
Toggle Commented Dec 2, 2017 on PIOMAS November 2017 at Arctic Sea Ice
Hi D_C_S, Not sure I grasped the entire argumentation, but I certainly like the idea of the deceleration of sea ice volume decline. The main arguments for future change in sea ice volume that I recognize, are: 1. Axial tilt: Luckily the axial tilt does not change much, and should help dampening any tendency of accelerating warming, simply as heat will continue escaping the polar area during the Arctic winter 2. Radiative forcing: More CO2 will increase radiative forcing, but it seems like the forcing will not increase as much as the increase in CO2. 3. Sea ice cover: Finally, the reduction in sea ice cover will increase heat influx from the atmosphere, which will tend to accelerate sea ice volume reduction. I have not considered other factors such as melting tundra, etc., just to focus on the main elements. The live experiment we are witnessing is how this will play out; will the combined impact be an accelerating volume loss (As trends indicate), or will we see a drawn out decline, as the seasonal changes will continue building sea ice during winter as happens in southerly areas such as the Gulf of Bothnia.
Toggle Commented Nov 28, 2017 on PIOMAS November 2017 at Arctic Sea Ice
No need, good to see you keep the ship straight Neven, thanks.
Toggle Commented Nov 28, 2017 on PIOMAS November 2017 at Arctic Sea Ice
Separately, is that Viddaloo above with the name-calling?
Toggle Commented Nov 28, 2017 on PIOMAS November 2017 at Arctic Sea Ice
@Rob, Yes, with all trends going in the same direction it certainly seems like we are headed for a major crash in the next few years, or the trend will need a significant shift.
Toggle Commented Nov 28, 2017 on PIOMAS November 2017 at Arctic Sea Ice
As mentioned Thursday the anti-cyclone has now centered around the Pole, which - unsurprisingly - has cooled down the central polar area. I would note that by this primitive 1980's pre-satellite approach we could observe from last week, how the temperatures would change, and that the cold spots near the Pole and in the Beaufort are indeed colder than the surface temps in the CAA. And let me then continue the old-fashioned forecasting by mentioning that the high now seems to move back to the Siberian side - which will make it really cold there, while temps in the CAA will continue rising in the next few days. So will the CAA this winter be the dominant Polar cold center? Not sure, it certainly could, but when a high broadens into Siberia as will now happen, then it just might influence what happens next.
Toggle Commented Nov 21, 2017 on PIOMAS November 2017 at Arctic Sea Ice
Hi AJT, Yes, DMI 80N did go up and is now coming down again. It will continue getting colder until tomorrow or early Tuesday as mentioned above, but the core of the cold will be slightly off the Pole towards Beaufort, and it is unlikely for the 80N temp to reach down to longterm average.
Toggle Commented Nov 19, 2017 on PIOMAS November 2017 at Arctic Sea Ice
Great update as always, thank you Neven! Regarding DMI 80N temp: From the ecmwf forecast it seems like the anti-cyclone on the Siberian side will deepen and move towards the geographic Pole. This seems to push winds in a southerly direction in the Fram, and I would therefore think the 80N temp will drop to the longterm average in about 4-6 days. Is that normal: Not really, since an ideal cold weather state like that in the past would have been colder than the average..
Toggle Commented Nov 16, 2017 on PIOMAS November 2017 at Arctic Sea Ice
Hi Agres, Sliding somewhat off topic here, but let me comment just once: The weather events with peak on 9/15 and again 10/29, while including very late season melting at coastal areas were both events of very significant mass balance gain for the GrIS: http://polarportal.dk/groenlands-indlandsis/nbsp/isens-overflade/ I don't see how these events contribute to ice sheet loss - rather it has been the years with blocking pattern type heat domes that have caused extraordinary melting, combined with accelerated melting by warmer sea water.
Toggle Commented Oct 30, 2017 on PIOMAS October 2017 at Arctic Sea Ice
Slightly OT, but wanted to let all know that DMI has launched an Arctic weather overview page with wind, temp, temp. anomaly, and precipitation anomaly: http://polarportal.dk/en/weather/ You already can find the other DMI measures here such as SIE, ice volume estimate, sea ice temp, the DMI 80N temp, satellite images, etc.
Toggle Commented Oct 20, 2017 on PIOMAS October 2017 at Arctic Sea Ice
As mentioned in my first post, I would say we are generally moving to a regime of less-frigid Arctic winters and cool summers, so yes; in all likehood another freak warm winter. That said, the current weather is somewhat anomalous for recent years, and I am curious how this will shape temps and wind in the CAB for the coming 1-2 weeks.
Toggle Commented Oct 13, 2017 on PIOMAS October 2017 at Arctic Sea Ice
Wow - not a huge crowd here these days.. Just wanted to note that the forecast remains for a good start to the Arctic winter: High pressure in the CAB with lows circulating in the northern parts of the continents, providing early extension of NH snow cover, while cooling down the Arctic waters. And then, for my old discussion with wayne about the relationship between the AO index and Arctic cold or sea ice: The current setup seems near ideal for a cold NH winter and for expanding sea ice, yet the AO index is currently positive, meaning that the overall air pressure above 60N is slightly below average. I was therefore not correct that a negative AO index (Above normal air pressure) would overall be positive for Arctic sea ice, as the distribution of high and lows seems to be much more important than the average air pressure.
Toggle Commented Oct 13, 2017 on PIOMAS October 2017 at Arctic Sea Ice
Thank you for another great PIOMAS update Neven! Given the weather with some storm activity in the CAB in Sept, I was surprised to see that volume went up as much and suspect that to some degree a new snow layer and snow-filled ponds on the ice have been measured as sea ice increase. That said, the ecmwf forecast is now showing a high to remain in the CAB for the next week, which will slow down winds and cool down temps, so that more actual sea ice growth will be possible. This summer IMO seems to have been an exemplary example of how the atmospheric conditions are changing in a warming Arctic: - Winters are relatively warm and humid at/near the CAB due to later cover of sea ice. - The Beaufort gyre is reduced, since high pressure areas increasingly tend to be based over land areas - both summer and winter (See e.g.: http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/piomas_ice_motion_anomaly_JanMarch2017.png ) - Winter-time low pressure areas above the sea ice will increase precipitation, which in addition to higher temps will insulate the ice and reduce sea ice formation, but at the same time should reduce sea ice export via the Fram Strait. - Reversely, the well-known pattern of summertime low pressure areas in the CAB is further strengthened, lowering temps, increasing cloud cover and thereby reducing sea ice melting. It seems clear to me that this is where we are heading, and the IPCC prediction models therefore seem to be reasonably accurate, as it could take a few more decades to reach an ice-free Arctic at Sept. minimum. Consequently, I cannot agree with scientists such as Prof. Peter Wadham, who still in 2016 predicted an ice-free Arctic in 2017 or 2018: https://www.theguardian.com/environment/2016/aug/21/arctic-will-be-ice-free-in-summer-next-year The only really interesting feature that I am considering is the relationship between Greenland and the CAB: For years such as 2007, 2012, 2013, and 2017 we have seen a strong correlation between average air pressure over the CAB and the air pressure over the Greenland ice cap. Especially in the fall of 2016, where tremendous storms rolled across Greenland with high levels of precipitation in October, the storms kept entering also the CAB. This year, the air pressure over Greenland has gradually increased and been fairly high and stable over the past couple of months. It will be interesting to see if this helps blocking storms from entering the CAB also..
Toggle Commented Oct 11, 2017 on PIOMAS October 2017 at Arctic Sea Ice