JAXA Global Sea Ice Extent as at 20 July 2019 : 22,604,544 km2We are now in the period of extent losses towards the false minimum of late August / Early September
In the last four days a switch from High Antarctic gains and low Arctic losses to an Antarctic loss and high Arctic losses. In 4 days data switched from a daily gain of 113,000 km2 to a loss of over 300,000 km2 in 2 days. A good demo of volatility that makes prediction of global sea ice even more of a mug's game.Global extent in 1st place, 169 k below 2017, and 929 k below 2018.
- extent
loss on this day 142 k, 127k different from the the average loss of 15 k on this day,
- extent gain from minimum to date is 6.36 million km2, 0.76 million km2 (10.7%) less than the average gain of 7.12 milllion km2 by this day,
-on average 78.9% of extent gain done and 107 days to maximum in early November.
We should have passed the false maximum of early July, and maybe this time we have...
For a bit less than 2 months more extent should fall until the false minimum (in early September), before rising to the (usually) true maximum around the 4th of November.
The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.51 million km2, 0.87 million km2 more than the record low maximum in 2016 and 2nd lowest in the satellite record.
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ps: quote from stephan
From a statistics point of view - and we look at two sets of almost independent data (Arctic and Antarctic) - one would guess that gains on the one side make up with losses on the other side (or vice versa) and the daily change should much more follow the green (average) line than the bumpy up and down line (of 2017 or 2019).
Any ideas why this is so?
If it was truly random it would be like 2 people independently tossing a coin. Each time, 4 possibilities.
Heads +1, Tails -1.
HH = +1 +1 = 2
TT = -1 -1 = -2
TH = -1 +1 = 0
HT = +1 -1 = 0
Does that mean that half the time variations from the average should cancel each other out?
Does that mean the graph suggests there is a connection between short-term changes in Arctic extent losses and Antarctic extent gains?
Or does it just mean I have muddied the waters even more?