ORH_wxman

Bumping this thread...while responding to new Vermonter das in the 2016-2017 winter thread, I went into my attachments to find an old snowfall map...I came across a bunch of images from last winter. All in all, last winter really was pretty decent for most. Def a bit more frustrating right on the coast, but even there it was still above average for snowfall. Some of my favorite images I saw were: The approach of the huge March 14th nor' easter. We had over 14 inches in ORH...this storm happened too right around when we closed on our new house. We had around 11-12 inches in Holliston judging by the landscape the next day driving there. This one hit all of New England hard save maybe parts of the south coast which flipped pretty early and some extreme exposed spots on the eastern MA shore...Logan underperformed a bit. We actually managed to avoid flipping to sleet in ORH despite most models thinking we would...the snow did get a bit rimed though late in the storm when we finally dryslotted: Here's the big thump on Sunday Feb 12th that gave us about 9 inches...that had followed the really nice snowstorm on February 9th...we achieved max depth after the 12th storm: Awesome banding in the February 9th storm:

Sea ice extent on Jaxa is currently 4.48 million sq km. That ranks 6th lowest...you can find the data here and click on "extent graph" at the top: https://ads.nipr.ac.jp/vishop/#/monitor NSIDC area is currently at 4.63 million sq km. That currently ranks 7th lowest. You can find the data here (need excel) ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/ or you can use their interactive graph: https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

We may be on "minimum area watch" right now...On September 1st, the NSIDC (what CT SIA used when they were functioning) dropped to 2.99 million sq km. It then rebounded significantly before declining again, though the declines have been weak and we remain 130k above the minimum at 3.12 million sq km. If September 1st was indeed the minimum area, it would be the earliest area min since 2005 when the minimum occurred on August 31st. August 31st is also tied for the earliest area minimum with 1987. If 2.99 million sq km ends up being the minimum area, this would be 5th lowest. Only 2012, 2016, 2011, and 2007 were lower...it is nearly tied with 2008 which finished at an even 3.00 million sq km. It is still possible that area makes one more push and we achieve a new low...if it drops below 2.90 million sq km, then it could surpass 2007 and 2011. But time is rapidly running out and the weather does not look conductive to a big 2nd week September area decrease. Any push would have to come from the Atlantic side most likely (and very soon in the next couple days) since there's still some southerly wind there from a Kara low...but the Pacific side may see ice growth over the next week as a very cold low moves over the CAA and adjacent CAB. In a reversal of position from mid-August, extent is currently only 6th lowest or 7th lowest depending on the source you use (jaxa vs NSIDC). Recall that extent had been running more like 3rd lowest a few weeks ago....but the higher area ranking back then suggested that the extent was unlikely to compact like last year and 2015 did late in the season, so we fell behind the pace of those years. Extent is currently at its season minimum...it is not clear when the min will occur...it might be in about 2-3 days if that cold low materializes in the CAA/CAB which will help promote ice growth in the Beaufort/adjacent areas on very cold north and east winds.

PIOMAS updated for the end of August... Looks like we've inched above 2016 for 4th lowest now...2011 was also lower and 2012 has gone well into the depths. Close race with 2010 too for the min volume, though I think we'll finish a little lower than 2010 but stay higher than 2016.

One is using SSMI/S satellite, the other is using AMSR2. The SSMI/S (which is what NSIDC uses) tends to be a bit more volatile on a day to day basis...the two data sources will generally track the same direction over a period of weeks, but within a small timespan such as a few days, you might see some differences.

Enchanted Rock in Fredericksburg, TX about an hour west of Austin would be my top spot for 2024. Went camping and hiking there many times as a very young kid.

Both 2015 and 2016 had extreme losses in extent the final week of August, so I'd expect 2017 to separate from them more by 9/1 on NSIDC. Jaxa is a little less obvious as 2015 didn't have as steep a drop late as NSIDC had. The U Bremen AMSR2 is probably a little more like NSIDC:

There is zero chance we stay above 5 million sq km on jaxa...we are already down to 5,047,907 on jaxa. The lowest loss in recent years I could find between now and the min was 2014 when we lost only 500k of extent. If you go back to 2006, then that year lost only 300k from here to the min. Most years seem to lose between 600-800k of extent from here on out which would put us in the 4.2-4.4 range. A couple years lost around 900k...so we could end up as low as 4.1 or as high as 4.7 if we use the extremes as end points. We prob won't lose the higher amounts given how compact the ice pack is, but we will still easily be in the mid 4s on jaxa without a problem IMHO. NSIDC is a different story as it tends to run about 200k higher...jaxa had that revision in their method about 3 years ago which made it less compatible with NSIDC.

The definition of extent is anywhere within a grid cell that is >15% ice coverage/concentration. So if a 10km by 10km grid cell had 50% ice concentration, then it is classified as 100km² of ice extent. However, area calculates this as 50km² of ice coverage because it takes concentration into account. The reason we even had extent in the first place is because we didn't have satellites that could view the ice in very high resolution...the grid cells were typically 25km by 25km....because ice moves a lot and the satellites also pick up some false ice or false water (when melt ponding occurs), the extent method was deemed more consistent and a conservative measurement of the ice. As we get higher and higher resolution of satellites, we will probably eventually get to the point where area is equal to extent. But for historical comparison, NASA still uses the 25km grid size method...using a smaller one like from AMSR2 (as low as 3km) and comparing it to 25km cells wouldn't be an apples to apples comparison. JAXA has tried to adjust for these differences in their own historical data.

There hasn't been any trend in minimum date since records began...but it's possible we start seeing it trend earlier if we get more years with open water close to the pole. But years like 2007 and 2012 had pretty late minimums...so the open waters those years did not facilitate early mins. It is still almost entirely weather dependent.

We would need perfect weather I think to get a minimum in August for extent...I don't think it's ever happened in the jaxa record. Earliest I could find was 9/1 in 1997...looks like 1988 was 9/2. It admittedly might be a little easier to get a min in August with less ice extent than previous years if there's some open water pretty close to the pole...as that will tend to freeze much earlier than the peripheral areas. We sort of saw this last year when we had a min on 9/7...pretty early. Area has twice had minimums in August...2005 and 1986 I believe. Both were on August 31st I believe.

We had a really compact ice pack with very few regions of very low concentration so it is not a huge surprise that we've seen a stall in extent while area has resumed its drop (after stalling earlier). The weather was never that great for losing a lot of extent this past week...we did get that cyclone earlier, but it never got nearly as intense as the 2012 cyclone and it occurred over a pack that was not nearly as shredded as 2012.

Update for 2017.... Extent is still tracking pretty low...basically in a dead heat right now with 2016 for 4th lowest, though I would be surprised if it kept up pace since 2016 had breathtaking losses late in the month with a ton of vulnerable nearly-melted-out ice in the ESS and managed to finish 2nd lowest...2017 has no such vast areas so vulnerable, so we'd expect a slowdown relative to 2016. That said, there is still room for a pretty low result, top 5 lowest is still definitely within reach and you still cannot quite rule out 2nd lowest if the weather was absolutely hostile to the max. But the race may be more with 2011/2015. Area is a bit of a different story...the ice is pretty compact...not nearly as spread out as some other years. So area is running higher than extent in the rankings. Here are the August 17th (based on 8/16 satellite scan) area numbers by year: 2017: 3.69 million sq km 2016: 3.26 2015: 3.51 2014: 4.53 2013: 4.10 2012: 2.92 2011: 3.32 2010: 3.92 2009: 3.95 2008: 3.67 2007: 3.23 2008 is currently the closest match, then 2015 is next closest. 2008 finished at 3.00 million sq km while 2015 finished at 3.09 million sq km. The ice pack is currently more compact than both of those years so it wouldn't be shocking if it finished higher...however, it is also probably thinner out on the PAC side, so that could offset the compactness some and still produce area losses that are more comparable to a dispersed ice pack....weather of course will be a factor too, so we'll just have to see. A finish anywhere from 3rd lowest to 7th lowest is still plausible on area...I think 2012 and 2016 are now safely out of reach as well as 2009, 2013, and 2014.

Yeah it's actually a pretty compact ice pack right now. I think the cyclone perhaps has just slowed the peripheral melting. Though bluewave is correct that typically cyclones over the CAB try and disperse the ice. But the concentration hasn't suffered even if it is doing that.

Cryosphere Today...it was a webpage from U Illinois that tracked sea ice area from the SSMI/S satellite. NSIDC uses the same one but they don't really show much data on area...all their graphs are extent. CT put the area in graphical format and also in tabular format. But it stopped transmitting data sometime in early 2016...at first they said they were going to be back soon but then the site went dark and it never updated. Area is nice to use because it tends to be a better predictor of extent 30-60 days out than extent itself is...but not having CT's easy-to-read data is really annoying.

NSIDC (CT SIA's source) is still transmitting SSMI/S and wipneus posts it...but it is really annoying that we don't have it on the CT SIA graph and also their spreadsheet which made it easy to look up. But area right now sits at 4.03 million sq km. That would be 7th place...barely under 2010 . Other years: 2016: 3.70 2015: 3.79 2014: 4.55 2013: 4.31 2012: 3.09 2011: 3.56 2010: 4.06 2009: 4.33 2008: 3.89 2007: 3.68

We have a pretty compact ice pack right now...area is running about 6th lowest but extent is flirting around the 3rd lowest mark right now only above 2007 and 2012 though on a few of the data sources it is a bit above 2016 as well. My guess is that we may see extent loss slow some at some point and area loss pick up a little more or at least pick up relative to extent loss. Most of the years with similar compactness right now saw some noticeable slowing of extent loss. We have a pretty strong storm right now in the Arctic and it is late enough in the season that perhaps it could do some damage. Kind of like the 2012 cyclone but less extreme since it is both weaker and the ice this year is not as in bad shape as 2012 was before that cyclone hit. We will see if it damages the ice enough to cause a late season cliff in extent loss. I'm probably leaning against anything huge though given the higher area right now...but you never know. If we form a potent dipole late in August that helps compact the ice more we could see big extent loss anyway like we saw in 2015 (that year ended on a huge extent cliff even while area loss was light)

The cold pool in the North Atlantic also really expanded and intensified in 2013 which was right after the huge Greenland melt in 2012...so I wonder if that was at least partially related.

There is a cyclical pattern on top of the underlying anthropogenic warming. The Arctic is kind of a tough one though because it has previously responded to global temperature changes much more rapidly than other regions...so we don't have a great idea on how it will behave with added anthropogenic warming. We do know that it warmed about 5x the rate of the rest of the globe in the early 20th century and cooled about 5x the rate during the cooling period 1940-1970...and recently it has warmed about 10x faster than the rest of the globe. There's probably been some natural warming helping out since the mid 90s when the AMO flipped on top of anthro warming. As for the ice, there was a paper that came out (Tietche et al) in 2011 that had looked at what happens when we approach an ice-free state and if it caused any "tipping point". It found that it did not...it actually found the opposite conclusion...which suggested as we get closer to ice free, it may take longer to get that final push than it did to go from 1990s levels to 2007 levels of ice. It showed that winter temps need to be about 2-3C warmer than currently (or maybe another 1-1.5c if you just use last winter's excessively warm temps) to consistently have a great chance to melt all the ice out in summer using model projected 2050 temps. Now, maybe this is too optimistic for the ice...it has shrunk faster than previous models said it would so we will have to see if that trend continues...or if the flattening happens. There's some recent argument for both cases...on the one hand, we have basically a flat trend in area/extent since 2007 and we've seen rebounds following record lows which follows the Tietche et al theory, but the volume trend is still downward too so will there some "flash melting" type event? Maybe...if we keep the volume trend down, then yeah it could happen pretty soon. But we've seen volume rebounds after records so of the same happens after this season, then it will probably push the ice-free date back another couple years.

Yeah the vortex is mostly hanging out over the CAB...there's a pretty strong storm in the couple days...we'll see if that is strong enough to do any damage. But it is definitely not the typical pattern for huge melting out shown through mid-month. The biggest enemy of the ice is how thin it was at the beginning of the year. If this pattern happened in 2015, we probably would have seen a minimum extent in the mid 5s.

PIOMAS updated for August 1st....2017 has now relinquished its place for lowest volume to 2012 for the first time this year...albeit still very close. I think it is unlikely 2017 will be able to match 2012's losses from here on out, but if the weather is bad enough, who knows for sure.

The effect is too small to really make a difference. Maybe only 0.3 watts per meter sq in high amplitude cases....which might be like a tenth of a degree Celsius, but most likely the impact is less. If we had an extended min for like a decade or longer, then it might be somewhat noticeable.

You're correct...you can use the other years as baselines....higher ice years like 2009 and 2014 are larger positive values.

Late month update on area....how other years compare to 2017: 2016: -300k 2015: -190k 2014: +340k 2013: +50k 2012: -520k 2011: -330k 2010: -110k 2009: +410k 2008: +350k 2007: -320k We are closest to 2013 right now, but when you look at the numbers, it doesn't necessarily that means where we will end up. You can see that 2008 still had pretty high area at this point (350k ahead of 2017 and 300k ahead of 2013), but much of it was vulnerable ice in the Laptev so it melted back quite a bit in August....whereas a year like 2013 had already melted out most of the vulnerable ice so it stalled and finished significantly higher than a year like 2008. The next closest year is 2010. I still think a finish close to 2010 is probably the most likely right now. That year finished at 3.07 million sq km for area....though really anything plus or minus 200k from that is fair game.

There's some good stuff in there if you just wade through all the hyperbole. Wipneus does a fantastic job on NSIDC area and extent data and piomas volume data...that's the main reason I visit the site at all.