In other news, there has been a late spurt in JAXA sea ice melt, which seems likely to take 2016 minimum past 2007, and exceeding only 2012. NSIDC says similar.
And OT, but the Blogger platform has been a bit shaky lately. I think the only thing affecting users at the moment is that on Chrome the blogroll is updated but not always kept in time order. Firefox seems OK. I'm reluctant to intervene, since I don't have a good javascript diagnostic tool on Chrome.
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The BOM ENSO Outlooks indicates models are showing a small rise in ONI for the rest of the year and into 2017, so the GISS June .79 ℃ may be the approximate bottom for several more months, and then who knows... could be El Niño time.
ReplyDeleteLikewise, the CFSV2 UM CCI and WxBELL global temperature anomaly estimates were up slightly. Both were 0.38C for July with UM CCI at 0.41C and WxBELL 0.42C for August, referenced to 1981-2010. The August UM CCI estimate is based on preliminary daily estimates and might change slightly when final estimates are published. The slight rise in August appears to be driven largely by another sharp upward spike in the Antarctic temperature anomaly, as happened in July. The Antarctic had a large downward spike in June and appears to be driving most of the change in the monthly global estimates the last three months.
ReplyDeleteInteresting about the sea ice extent downward jog. I notice that average temperatures are below freezing in much of the Arctic Ocean now, so I'm guessing the extent reduction is most likely from wind effects. NASA Worldview has high resolution MODIS and VIIRS imagery and the ice is easier to see with the 7-2-1 and 3-6-7 MODIS composite images (ice showing as blue and red respectively). When zooming in to the highest resolution the ice coverage percentage is difficult to assess visually and appears greater with the 3-6-7 composite. There are often lots of clouds in the way for days, so a sudden clearing over a newly opened area could also make a quick reduction in the extent estimates.
Bryan, yes there seems to be not much change lately, and what there is depends on the Antarctic (or what we know of it).
DeleteBryan - At the end of the sea ice melt season, as the air cools below freezing, sea ice is still being slowly melted by the ocean that has stored heat over the summer. Satellite pictures currently show an unusually blue arctic i.e., not much ice overall. Widespread low sea ice concentrations are the root cause of the large late season extent drop this year since many areas are vulnerable to dropping below the 15% extent threshold.
DeleteChubbs
Chubbs, that does make sense and probably explains why the ice minimum is normally in September each year even though the average temperature maximum is in July. I can also see how wind plays an important role in the fringe areas where ice coverage is less than 50%. Using the 15 percent coverage metric that seems popular these days should be very prone to substantial wind effects. If the extent metric was 5o% instead of 15%, wind would likely have much less effect. I wish ice extent would be reported at several coverage percentages, like 75%, 50%, 25%, and 15%. That would be interesting to track and compare over time.
DeleteI notice that daily mean temps north of 80N ( see http://ocean.dmi.dk/arctic/meant80n.uk.php ) have gone above normal values the past few days. This may be the
ReplyDeletecause of the melting spurt.