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Author Topic: 2016 sea ice area and extent data  (Read 290185 times)

jdallen

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Re: 2016 sea ice area and extent data
« Reply #250 on: May 19, 2016, 07:36:00 PM »
With the heat coming in (looking at Climate Reanalyzer), I'm expecting both the Bering and Okhostsk to get finished off this week, and major inroads made into the Chukchi, Kara and Barents.

There will be heat along the Beaufort as well, but I'm not sure that will have as much of an impact on numbers.  It's quite possible we'll see a slackening of pace similar to that pointed out by OldLeatherneck on a different thread.
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sedziobs

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Re: 2016 sea ice area and extent data
« Reply #251 on: May 19, 2016, 07:49:39 PM »
The bigger impact on Beaufort may be the return of high pressure in the central Arctic, which gradually builds through the forecast.  That should result in winds further expanding the open water area.

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #252 on: May 20, 2016, 04:48:19 PM »
The shadow CT-area report:
> source("xctarea.R")

day  CT-date       NH               SH                Global
Thu 2016.3753  -33.3 10.287944 +129.6  8.167545   +96.3 18.455489
Fri 2016.3781  -72.1 10.215796 +144.5  8.312095   +72.4 18.527891
Sat 2016.3808  -73.6 10.142238  +29.9  8.342009   -43.6 18.484247
Sun 2016.3836  -56.5 10.085746  +82.1  8.424107   +25.6 18.509853

Baffin, Chukchi and OKhotsk dropped each about -12k. ESS went up +11k.

Shadow NSIDC is 11.6092 (-108k4). Okhotsk dropped -31k (129k remaining) , Bering -16k (100k remains) StLawrence -13k (30k remains). Greenland Sea dropped -17k (plenty left).

An overview of the changes can be seen in the attached delta map.

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #253 on: May 21, 2016, 04:35:58 PM »
Shadow CT-area report:

day  CT-date       NH               SH                Global
Fri 2016.3781  -72.1 10.215796 +144.5  8.312095   +72.4 18.527891
Sat 2016.3808  -73.6 10.142238  +29.9  8.342009   -43.6 18.484247
Sun 2016.3836  -56.5 10.085765  +82.4  8.424402   +25.9 18.510167
Mon 2016.3863  -26.0 10.059755   -0.2  8.424190   -26.2 18.483945

Baffin decreased by -25k, the CAB rebounded +13k.

Shadow NSIDC is 11.5957, down -13k. Hudson took care of that: -15k.
 
An overview of the changes can be seen in the attached delta map.

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #254 on: May 22, 2016, 04:28:54 PM »
Shadow CT-area report:

day  CT-date       NH               SH                Global
Sat 2016.3808  -73.6 10.142238  +29.9  8.342009   -43.6 18.484247
Sun 2016.3836  -56.5 10.085765  +82.4  8.424402   +25.9 18.510167
Mon 2016.3863  -25.9 10.059819   -0.4  8.423993   -26.4 18.483812
Tue 2016.3890  -68.6  9.991219  +66.9  8.490880    -1.7 18.482099


That is due to the big drop in Kara (-43k) and a much lesser one in Hudson region (-22k).

The shadow NSIDC extent is 11.6247  (+29k). The uptick comes from Okhotsk (+20k) and Greenland Sea (+13k). Hudson dropped -15k.

In the attached delta map, the concentration drop in Kara is clearly visible.



BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #255 on: May 22, 2016, 04:46:07 PM »
Update for the week to May 21st

The current 5 day mean is on 11,665,400km2 while the 1 day extent is at 11,625,000km2.

The daily anomaly (compared to 81-10) is at -1,481,130km2, an increase from -1,380,810km2 last week. The anomaly compared to the 07, 11 and 12 average is at -1,035,250km2, an increase from -935,880km2 last week. We're currently the lowest on record, the same as last week.



The average daily change over the last 7 days was -59.7k/day, compared to the long term average of -45.4k/day, and the 07, 11 and 12 average of -45.5k/day.
The average long term change over the next week is -48.8k/day, with the 07, 11, and 12 average being -54.7k/day.



The extent drop so far this May is the 2nd largest on record. To achieve the largest monthly loss, a drop of at least 65.8k/day is required, while the smallest loss requires an increase of at least 66.5k/day and an average loss requires a increase of 1.9k/day.


abbottisgone

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Re: 2016 sea ice area and extent data
« Reply #256 on: May 22, 2016, 06:10:54 PM »
..typos?
..
But I left school and grew my hair
They didn't understand
They wanted me to be respected as
A doctor or a lawyer man
But I had other plans..........

Nick_Naylor

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Re: 2016 sea ice area and extent data
« Reply #257 on: May 22, 2016, 08:33:52 PM »
The 5-day mean looks understated. Are you seeing something else?

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #258 on: May 22, 2016, 09:19:06 PM »

Nick_Naylor

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Re: 2016 sea ice area and extent data
« Reply #259 on: May 22, 2016, 09:23:33 PM »
..typos?

Where?

Shouldn't the 5 day mean be at least 100k higher than the most recent extent?

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #260 on: May 22, 2016, 09:28:31 PM »
..typos?

Where?

Shouldn't the 5 day mean be at least 100k higher than the most recent extent?

The daily extent values have actually risen slightly in the last 3 days (19th: 11.609, 20th: 11.596, 21st: 11.625), hence the small gap now between the single day and 5 day average.

If there isn't a big drop in the daily value tomorrow, the 5 day average will see a big slow down too.

Nick_Naylor

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Re: 2016 sea ice area and extent data
« Reply #261 on: May 22, 2016, 10:04:36 PM »
Thanks. I sure didn't see that in the curve  :o

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #262 on: May 23, 2016, 10:26:43 AM »
Thanks. I sure didn't see that in the curve  :o

My own graphs use the 5 day average, as do the NSIDC. I can try to make that more clear in future posts.

Nick_Naylor

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Re: 2016 sea ice area and extent data
« Reply #263 on: May 23, 2016, 01:01:17 PM »
That might be helpful, although in retrospect the charts are obviously too smooth to be anything else.
What I meant to say is that - even knowing it's a 5 day average - it's hard to see what daily values would have to be in order to give the chart and the stats at the same time.
I'm still not understanding what prompted the original "typos?" posting though.

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #264 on: May 23, 2016, 04:20:20 PM »
The shadow CT-area report:

day  CT-date       NH               SH                Global
Sun 2016.3836  -56.5 10.085765  +82.4  8.424402   +25.9 18.510167
Mon 2016.3863  -25.9 10.059819   -0.4  8.423993   -26.4 18.483812
Tue 2016.3890  -68.5  9.991272  +66.9  8.490915    -1.6 18.482187
Wed 2016.3918  -94.4  9.896835  +69.8  8.560710   -24.6 18.457545

Hudson (-36k), Chukchi (-25k) and Beaufort (-18k) are main contributors.

Shadow NSIDC for 2016/5/22 was 11.5913  (-33.3k). No particular region stands out.

The changes can be seen in attached delta map.

Rob Dekker

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Re: 2016 sea ice area and extent data
« Reply #265 on: May 24, 2016, 06:59:33 AM »
Wipneus,
I'm sure that I speak on behalf of the ASIB/ASIF community if I want to THANK YOU for the marvelous work you are doing.
Due to the F-17 issues, many of the regular sea ice information sources are disfunctional, which leaves your data as a crucial source of information of what is going on during this epic melting season.

Especially the AMSR2 regional graphs that you produce on the arctischepinguin site are essential, as and the 'shadow' CT area and 'shadow' NSIDC area and extent info are just phenomenal.

Just one question : Do you have a graph (or a data file) for the 'shadow' CT area and 'shadow' NSIDC area and extent ?

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #266 on: May 24, 2016, 09:27:42 AM »
Wipneus,
I'm sure that I speak on behalf of the ASIB/ASIF community if I want to THANK YOU for the marvelous work you are doing.
Due to the F-17 issues, many of the regular sea ice information sources are disfunctional, which leaves your data as a crucial source of information of what is going on during this epic melting season.

Especially the AMSR2 regional graphs that you produce on the arctischepinguin site are essential, as and the 'shadow' CT area and 'shadow' NSIDC area and extent info are just phenomenal.

Just one question : Do you have a graph (or a data file) for the 'shadow' CT area and 'shadow' NSIDC area and extent ?

Data files:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/AreaCalculatedLikeCryosphereToday.txt
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_nt_nrt_main.txt

Browse in the folder for antarctic and regional data files.

I do not graph CT-area at all, it is not a very good indication of area IMHO. Area in the NSIDC files/graphs (sometimes referred to as NSIDC-area) is calculated from the same SIC data in the way as you would have expected it.

NSIDC extent (and area) appear in many of graphs. Some samples:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-nt-regional-area-overview.png
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-nt-regional-extent-overview.png
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-area-multiprod.png
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-extent-multiprod.png

Browsing in the folders is allowed.

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #267 on: May 24, 2016, 09:56:06 AM »
That might be helpful, although in retrospect the charts are obviously too smooth to be anything else.
What I meant to say is that - even knowing it's a 5 day average - it's hard to see what daily values would have to be in order to give the chart and the stats at the same time.
I'm still not understanding what prompted the original "typos?" posting though.

I'm always open to suggestions, whether it be for new graphs or different ways to explain what they're showing. I'll see if I can change the wording to make the post more clear next time, maybe some extra stats to clarify things too.

oren

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Re: 2016 sea ice area and extent data
« Reply #268 on: May 24, 2016, 10:41:36 AM »
Wipneus,
I'm sure that I speak on behalf of the ASIB/ASIF community if I want to THANK YOU for the marvelous work you are doing.
+1

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #269 on: May 24, 2016, 02:03:53 PM »
ADS-NIPR Extent:
10,880,319 km2 (23 May)
Down 3,062,188 km2 (21.96%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,702,864 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 43,644 km2 (-.4%) from previous day.
Down 317,590 km2  (-2.84%) over past seven days (daily average: -45,370 km2).
Down 1,413,128 km2  (-11.55%) for May (daily average: -61,440 km2).
1,126,654 km2 below 2000s average for this date.
708,050 km2 below 2010s average for this date.
436,128 km2 below 2015 value for this date.
1,007,308 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 23 May) average.
Lowest May to-date average.
Lowest value for the date.
89 days this year (62.24% year-to-date) have recorded the lowest daily extent.
27 days (18.88%) have recorded the second lowest.
14 days (9.79%) have recorded the third lowest.
130 days in total (90.91%) have been among the lowest three on record.


CT Area:
9,896,835 km2 (24 May [Day 0.3917])
Down 3,024,523 km2 (23.41%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
7,662,826 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 94,437 km2 (-.95%) from previous day.
Down 424,409 km2 (-4.13%) over past seven days (daily average: -60,630 km2).
Down 1,320,497 km2 (-11.86%) for May (daily average: -55,021 km2).
1,010,888 km2 below 2000s average for this date.
603,686 km2 below 2010s average for this date.
583,022 km2 below 2015 value for this date.
736,273 km2 below 2012 value for this date.
* - Due to ongoing satellite issues, multiple days in the Cryosphere Today 2016 data are missing and/or invalid; for that reason, this table incorporates sea ice area figures as calculated by Wipneus using NSIDC's numbers.




Wipneus

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Re: 2016 sea ice area and extent data
« Reply #270 on: May 24, 2016, 04:30:37 PM »
Today's shadow CT-area report:

day  CT-date       NH               SH                Global
Mon 2016.3863  -25.9 10.059819   -0.4  8.423993   -26.4 18.483812
Tue 2016.3890  -68.5  9.991272  +66.9  8.490915    -1.6 18.482187
Wed 2016.3918  -94.5  9.896804  +69.8  8.560710   -24.7 18.457514
Thu 2016.3945 -119.9  9.776938  +47.6  8.608303   -72.3 18.385241

The century+ drop is brought to us by Beaufort (-21k), Chukchi(-26k), ESS(-19k) and CAB(-13k). Baffin contributed -12k.

Shadow NSIDC extent is 11.4880 (-103k3 ). Here the contributors were Okhotsk(-17k), Hudson (-14k), Beaufort (-13k)  and Bering (-12k). Baffin went up by 12k.

In the attached delta map, the broad region of concentration drop from Beaufort via Chukchi to ESS can be noticed. Perhaps a sign of surface melt.

Comradez

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Re: 2016 sea ice area and extent data
« Reply #271 on: May 24, 2016, 06:17:33 PM »
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st. 

AmbiValent

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Re: 2016 sea ice area and extent data
« Reply #272 on: May 24, 2016, 06:48:52 PM »
Area is not uniformly lost, it depends on how thick the ice is in that area. So you can't really look at past years and assume the same area would be lost.

That being said, right now it looks to me like the multi-year ice is mostly safe while the first-year ice is being threatened by melt sooner or later this year. (While in 2012, the heat had to melt a bunch of multi-year ice to get to the record)
Bright ice, how can you crack and fail? How can the ice that seemed so mighty suddenly seem so frail?

jdallen

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Re: 2016 sea ice area and extent data
« Reply #273 on: May 24, 2016, 08:43:27 PM »
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st.
Reasonable assumptions, but I will be very surprised if we pass 10 million km2 by June 1.  If similar weather continues in June, we could easily see over 2.5 million km2 of melt in both June and July, and potentially almost 2 million in August.  It's going to be about the momentum - additional heat picked up early amplifying later melt.
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bbr2314

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Re: 2016 sea ice area and extent data
« Reply #274 on: May 24, 2016, 08:45:35 PM »
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st.
Reasonable assumptions, but I will be very surprised if we pass 10 million km2 by June 1.  If similar weather continues in June, we could easily see over 2.5 million km2 of melt in both June and July, and potentially almost 2 million in August.  It's going to be about the momentum - additional heat picked up early amplifying later melt.
We are already at 9.77M KM2...

jdallen

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Re: 2016 sea ice area and extent data
« Reply #275 on: May 24, 2016, 08:48:46 PM »
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st.
Reasonable assumptions, but I will be very surprised if we pass 10 million km2 by June 1.  If similar weather continues in June, we could easily see over 2.5 million km2 of melt in both June and July, and potentially almost 2 million in August.  It's going to be about the momentum - additional heat picked up early amplifying later melt.
We are already at 9.77M KM2...
ADS-NPR extent is at 10.8 as shown above.  What measure are we looking at?

[edit: AH, you were speaking of area, not extent.  My mistake.  Yes, sub 9.5 by 6/1 is very probable if not impossible to avoid.]
« Last Edit: May 24, 2016, 08:54:30 PM by jdallen »
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Tealight

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Re: 2016 sea ice area and extent data
« Reply #276 on: May 24, 2016, 11:14:14 PM »
I think 2016 will defenitly set a new record low for average sea ice area this year. Currently we are 250,000 km2 below the previous record and it seems to be increasing further.

Year    million km2
2007   12.38
2011   12.26
2012   12.68
2015   12.40
2016   12.01

DavidR

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Re: 2016 sea ice area and extent data
« Reply #277 on: May 25, 2016, 12:59:35 AM »
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st.
Average melt over the last 10 years to June 1st  is 665K km^2 taking area to 9.1 M.
Three years take area below 9M and 2014 melt takes it  down to 8.8. So its definitely doable.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #278 on: May 25, 2016, 01:56:24 PM »
ADS-NIPR Extent:
10,792,665 km2 (24 May)
Down 3,149,842 km2 (22.59%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,615,210 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 87,654 km2 (-.81%) from previous day.
Down 352,054 km2  (-3.16%) over past seven days (daily average: -50,293 km2).
Down 1,500,782 km2  (-12.27%) for May (daily average: -62,533 km2).
1,165,979 km2 below 2000s average for this date.
737,015 km2 below 2010s average for this date.
482,997 km2 below 2015 value for this date.
1,053,737 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 24 May) average.
Lowest May to-date average.
Lowest value for the date.
90 days this year (62.5% year-to-date) have recorded the lowest daily extent.
27 days (18.75%) have recorded the second lowest.
14 days (9.72%) have recorded the third lowest.
131 days in total (90.97%) have been among the lowest three on record.


CT Area:
9,776,938 km2 (25 May [Day 0.3945])
Down 3,144,420 km2 (24.34%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
7,542,929 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 119,866 km2 (-1.21%) from previous day.
Down 511,040 km2 (-5.%) over past seven days (daily average: -73,006 km2).
Down 1,440,394 km2 (-12.93%) for May (daily average: -57,616 km2).
1,043,275 km2 below 2000s average for this date.
670,951 km2 below 2010s average for this date.
707,050 km2 below 2015 value for this date.
822,586 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.3945) average.
Lowest May to-date average.
Lowest value for the date.
* - Due to ongoing satellite issues, multiple days in the Cryosphere Today 2016 dataset are missing and/or invalid; for that reason, this table incorporates sea ice area figures as calculated by Wipneus using NSIDC's numbers. (Thanks, Wipneus!)




Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #279 on: May 25, 2016, 02:29:17 PM »
As a note of comparison: were the rest of the 2016 melt season to progress exactly as the 2007 melt season, 2016 SIA would drop below the previous 2012 record for a total of 32 days; were it to follow 2012's trajectory, it would spend a whopping 50 days below the previous record, bottoming out at 1.41 million km2.

Similarly, for sea ice extent, a repeat of 2007's trajectory would see 2016 spending 17 days below the 2012 record, while a repeat of 2012 would also see 2016 spend a full 50 days below the existing record, reaching a nadir of 2.12 million km2.

« Last Edit: May 25, 2016, 04:33:31 PM by Jim Pettit »

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #280 on: May 25, 2016, 04:20:52 PM »
Shadow CT-area report:

day  CT-date       NH               SH                Global
Tue 2016.3890  -68.5  9.991272  +66.9  8.490915    -1.6 18.482187
Wed 2016.3918  -94.5  9.896804  +69.8  8.560710   -24.7 18.457514
Thu 2016.3945 -119.5  9.777306  +47.7  8.608370   -71.8 18.385676
Fri 2016.3973  -63.8  9.713479  +71.0  8.679335    +7.1 18.392814

CAB (-19k), Kara (-14k) and Baffin (-14k) have the largest area drops.

Shadow NSIDC extent is now: 11.4006 ( -87k5). Baffin (-29k), Bering (-20k) and Beaufort (-16k) dropped most in extent.

In the delta map the concentration drop near the Pole that was noticed in the "homebrew" thread is also seen by the F18 satellite and Nasa Team algorithm.

AmbiValent

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Re: 2016 sea ice area and extent data
« Reply #281 on: May 25, 2016, 04:35:22 PM »
Hm... in Wipneus' post 2016.3945 means Thursday, in Jim Pettit's it means Wednesday. Which is it?
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dnem

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Re: 2016 sea ice area and extent data
« Reply #282 on: May 25, 2016, 04:48:44 PM »
I'd guess the confusion is related to counting leap day (or not).

FWIW, I did something similar to what Jim did above.  A appended 2012 losses on to the current ADS-NIPR extent and confirm his minimum of 2.12 km^2.  I also appended average losses for the three years with the lowest minima (2012, 2007 and 2015) onto the current extent and the result looks a lot like 2012 overall with a minimum of 3.05 km^2.  I also appended the average loses of the three highest minima years since 2007 (2009, 2013 and 2014) onto the current extent.  That (highly unlikely) scenario would bring us to a minimum around 3.89 km^2 this fall.

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Re: 2016 sea ice area and extent data
« Reply #283 on: May 25, 2016, 06:31:30 PM »
Blame Cryosphere Today's day numbering. Thursday means the day of CT's data release, 2016.3945 is the date they will tag it with. But the ice concentration measure on Monday!

If that is confusing, the latest data (using yesterday's satellite measurements) is the last line in the report.

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Re: 2016 sea ice area and extent data
« Reply #284 on: May 25, 2016, 06:39:42 PM »
Speaking about Cryosphere Today, seems like they have gone bananas again.. Just look at those ridiculous numbers!

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Re: 2016 sea ice area and extent data
« Reply #285 on: May 25, 2016, 08:16:55 PM »
I long ago went with the Cryosphere Today method of simply ignoring the leap day (which shifted from leap year to leap year), mostly because it made it easier to align year-over-year graphs, and because the leap day conveniently falls near the annual maximum plateau. To maintain consistency across the different datasets I track and graph since then, I've stuck by that method for all metrics: extent, volume, temperature data, etc. Apologies for any confusion, but any method for dealing with leap years is going to cause issues somewhere. At any rate, that's yet another reason why year-to-year comparisons aren't really meaningful: noting that, for example, extent dropped by 30k today but went up by 30k on the same day last year is far less germane than noting that extent dropped by, say, 2 million this month and went up by two million the same month last year.

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Re: 2016 sea ice area and extent data
« Reply #286 on: May 26, 2016, 01:23:29 PM »
Down 3,149,842 km2 (22.59%) from 2016 maximum of 13,942,507 km2 on 29 February

I LOVE this weekly summary of ice that Jim Pettit does.  It gives us a "good look" against various other "yard sticks" to compare.

One way to look at 2016 is this:  We have burned through 3.15 million square kilometers of ice so far this year.  What is the amount of ice that we had burned through in 2012 (from peak ice that year to this date)?

I can "kind of eyeball" it on a chart....and it looks like we have burned through more ice (maybe about 500,000 more 2K).  But Jim....if you DO have the numbers.....I would be curious to know:  The absolute square kilometers burned through for 2012 from peak to May 25th of that year.

We know that 2016 is 1.054 million square kilometers below 2012.....but 2012 started at a much higher winter maximum (eyeballing it.....maybe 500,000 above the 2016 maximum).

Thanks.....

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Re: 2016 sea ice area and extent data
« Reply #287 on: May 26, 2016, 02:16:11 PM »
One way to look at 2016 is this:  We have burned through 3.15 million square kilometers of ice so far this year.  What is the amount of ice that we had burned through in 2012 (from peak ice that year to this date)?

I can "kind of eyeball" it on a chart....and it looks like we have burned through more ice (maybe about 500,000 more 2K).  But Jim....if you DO have the numbers.....I would be curious to know:  The absolute square kilometers burned through for 2012 from peak to May 25th of that year.

We know that 2016 is 1.054 million square kilometers below 2012.....but 2012 started at a much higher winter maximum (eyeballing it.....maybe 500,000 above the 2016 maximum).

Certainly. If my early morning math is correct:

2012 extent topped out at 14,709,086 km2 on 7 March
2016 extent topped out at 13,942,507 km2 on 29 February
Difference: 766,579 km2

On May 25, 2012, SIE stood at 11,797,276 km2, a loss from maximum of 2,911,810 km2, or 36,858 km2 per day.
On May 25, 2016, SIE stands at 10,704,953 km2, a loss from maximum of 3,237,554 km2, or 37,646 km2 per day.

So: very similar loss per day numbers, with the slight edge to 2016. Which doesn't sound too astounding until one considers that 2012 likely had more "easy" ice to lose in the first place.

FWIW, 2012 hit its first (and perhaps steepest) "cliff" on 5 June; that kicked off a ten-day spree of decrease that averaged 119k per day, and included seven consecutive century drops. It'll be interesting to see, then, how much of the current 2012-2016 spread disappears over the next three weeks. Some? Most? All?

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Re: 2016 sea ice area and extent data
« Reply #288 on: May 26, 2016, 02:31:46 PM »
Newbie questions & such, is there buoy data at depths for water temps & ‰ with location to use with the colored thickness maps?

Is it considered needed to have a new official category of ice, "rotten"? Some was cored last fall, the multi-year ice part of rafts left in fall looked rotten like parts of a glacier melting down get.

And noting that freeze-up is now pancake ice everywhere a change from prior eras what does that mean?

Last fall an expedition in the Beaufort found a warm layer 20m down, a storm caused ice to form and the next day it all melted in spite of low air temps from mixing that up, that to me was latent heat and that layer is there all winter.

So isn't this a new property of the fresher-colder Pacific water to the prior condition, that above warmer much deeper Atlantic water?

Thus my wonder is that it may thicken the surface heated layer to where it can transfer heat between the more saline layer deeper down an evolution of this?

Late April the Beaufort opened up radically, thinner than usual ice by 18% via a talk with NSIDC person posted online. An observation is that it can break up in days with a big storm any time from now on being this new type of ice, there was no big storm for the early opening this year by that talk, sequence shots: http://earthobservatory.nasa.gov/IOTD/view.php?id=88065&eocn=home&eoci=iotd_grid
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Re: 2016 sea ice area and extent data
« Reply #289 on: May 26, 2016, 03:14:58 PM »
Jim...thanks for getting those numbers.

2012 extent topped out at 14,709,086 km2 on 7 March
2016 extent topped out at 13,942,507 km2 on 29 February
Difference: 766,579 km2

So....the melt year started out with 2016 having a 766,579 lead on 2012.  And now that lead has grown to 1,053,737 (an additional gain of 287,158 km2 from the peak).

Not surprisingly this would "seem" to support the fact that the ice is MUCH more vulnerable now because of its LACK of thickness.  Even though 2012 started out with what was quite likely a lot of "first year ice"......2016 has INCREASED its lead over 2012 by a fairly substantial amount.

And...I agree with you Jim.....the next few weeks or so could be quite interesting.

I do "believe" that 2016 will continue to "track in parallel fashion" 2012.....keeping its "lead" in tact...and that lead will GROW...especially when we get into late July and into August.



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Re: 2016 sea ice area and extent data
« Reply #290 on: May 26, 2016, 03:38:33 PM »

So: very similar loss per day numbers, with the slight edge to 2016. Which doesn't sound too astounding until one considers that 2012 likely had more "easy" ice to lose in the first place.

FWIW, 2012 hit its first (and perhaps steepest) "cliff" on 5 June; that kicked off a ten-day spree of decrease that averaged 119k per day, and included seven consecutive century drops. It'll be interesting to see, then, how much of the current 2012-2016 spread disappears over the next three weeks. Some? Most? All?

2012 didn't really have much more easy ice to lose than 2016. It did have a lot more ice in the Pacific but most of that was gone by June 1.

The figure below provides an estimate of the area of ice for various mean thicknesses in the PIOMAS April data.  As can be seen, for most of this period 2012 and 2016 have the same amount of ice despite 2016 starting with 800K km^2 less. 

According to  my  estimate 2016 is currently sitting in the 0.95 m panel for amount of area gone and 2012 is in the 0.85 column.  Based on this I am estimating that  2012 won't even close the gap much with 2016 in the next three weeks. and by June 16th 2016 will still be 800K km^2  below 2012.

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Re: 2016 sea ice area and extent data
« Reply #291 on: May 26, 2016, 04:14:08 PM »
2012 didn't really have much more easy ice to lose than 2016. It did have a lot more ice in the Pacific but most of that was gone by June 1.

Well, that's the "easy" ice to which I was referring.

At any rate, if you're correct in your estimation, things are going to get very, er, interesting come July and August...

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Re: 2016 sea ice area and extent data
« Reply #292 on: May 26, 2016, 04:35:28 PM »
Shadow CT-area report:

day  CT-date       NH               SH                Global
Wed 2016.3918  -94.5  9.896804  +69.8  8.560710   -24.7 18.457514
Thu 2016.3945 -119.5  9.777306  +47.7  8.608370   -71.8 18.385676
Fri 2016.3973  -63.8  9.713496  +71.0  8.679335    +7.2 18.392831
Sat 2016.4000  -66.1  9.647368  +27.5  8.706805   -38.7 18.354173

Baffin dropped -15k, Hudson, Kara and Beaufort each about -11k. ESS increased +16k.

Shadow NSIDC was 11.3791 ( -21.9k). Hudson changed most at -15k.

Attached delta map gives you another look . For instance the open water in the top of Baffin Bay looks big and is growing.

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Re: 2016 sea ice area and extent data
« Reply #293 on: May 26, 2016, 08:13:36 PM »
FWIW, 2012 hit its first (and perhaps steepest) "cliff" on 5 June; that kicked off a ten-day spree of decrease that averaged 119k per day, and included seven consecutive century drops. It'll be interesting to see, then, how much of the current 2012-2016 spread disappears over the next three weeks. Some? Most? All?

My rough guess: The 2012-2016 difference is now about 1.1M, by June 4 just before the cliff it will be about 900k, and by June 14 at the end of the cliff, it will be about 500k.

The guess is based on looking at Wipneus' regional graphs at the Arctic Sea Ice Graphs page. The biggest contributor to the reduction in the difference is Bering Sea which still had about 400k of easy ice left at this time in 2012. The error margins are big though as many regions are dropping fast and just a couple of days difference in timing can mean a big difference in the extent.

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Re: 2016 sea ice area and extent data
« Reply #294 on: May 26, 2016, 08:54:50 PM »
I am no expert, but surely what will make the difference is what happens in the central Arctic Basin? Most other areas can be expected either to become ice free, as they have in most recent years, or to hold onto a little bit of tough multi-year / calved ice. But it's in the CAB that 2012 was different
.. and what I'm wondering is what happens if we see an early start to the melt there?

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Re: 2016 sea ice area and extent data
« Reply #295 on: May 26, 2016, 10:25:58 PM »
snip

Don't ask questions that aren't tied directly to sea ice area and extent data in this thread. Ask in the buoy thread.
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Re: 2016 sea ice area and extent data
« Reply #296 on: May 27, 2016, 06:49:17 AM »
snip

Don't ask questions that aren't tied directly to sea ice area and extent data in this thread. Ask in the buoy thread.

Yes, that's more of a volume thing anyway. At least I've come to avoid those threads that contain much something else than what's related to the topic. That said, will there be the June drop due the melt ponds this year too, now that CT is having issues? Is it seen in the Wipneus' numbers of area?
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Re: 2016 sea ice area and extent data
« Reply #297 on: May 27, 2016, 01:07:19 PM »
ADS-NIPR Extent:
10,652,073 km2 (26 May)
Down 3,290,434 km2 (23.6%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,474,618 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 52,880 km2 (-.49%) from previous day.
Down 389,153 km2  (-3.52%) over past seven days (daily average: -55,593 km2).
Down 1,641,374 km2  (-13.42%) for May (daily average: -63,130 km2).
1,220,829 km2 below 2000s average for this date.
763,419 km2 below 2010s average for this date.
529,970 km2 below 2015 value for this date.
1,090,443 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 26 May) average.
Lowest May to-date average.
Lowest value for the date.
92 days this year (63.01% year-to-date) have recorded the lowest daily extent.
27 days (18.49%) have recorded the second lowest.
14 days (9.59%) have recorded the third lowest.
133 days in total (91.1%) have been among the lowest three on record.


CT Area:
9,647,368 km2 (27 May [Day 0.4000])
Down 3,273,990 km2 (25.34%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
7,413,359 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 66,128 km2 (-.68%) from previous day.
Down 495,169 km2 (-4.91%) over past seven days (daily average: -70,738 km2).
Down 1,569,964 km2 (-14.1%) for May (daily average: -58,147 km2).
1,074,362 km2 below 2000s average for this date.
669,775 km2 below 2010s average for this date.
656,014 km2 below 2015 value for this date.
786,521 km2 below 2012 value for this date.
Lowest value for the date.
NOTE: due to the prolonged absence of official CT sea ice area data, I'm instead using Wipneus' calculated area numbers. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!
« Last Edit: May 27, 2016, 01:46:22 PM by Jim Pettit »

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Re: 2016 sea ice area and extent data
« Reply #298 on: May 27, 2016, 01:36:30 PM »
Thanks, Jim. I'm using this for the first ASI update.
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Re: 2016 sea ice area and extent data
« Reply #299 on: May 27, 2016, 01:50:34 PM »
1,090,443 km2 below 2012 value for this date.

Almost back up to the largest "spread" vs 2012 which was on the May 16th report of 1,107,XXX km2.




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