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Messages - Random_Weather

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1
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: February 06, 2020, 07:48:05 AM »
Interesting to have a near real time volume estimate.  Thanks for doing that.

What is the uncertainty range indicated on graph 95% CI (2.5% to 97.5% of estimate distribution)?

Is the current value calculated with same sources and methods as the 2011-2018 average?

How the Volume estimate using this method compare to PIOMAS volume for same dates?

Its min/max value + unc of the instruments, in a more formal way:

max_min+-Unc = Max_Min(Volume) for the Date +- the Volume of the instrumental Uncertainy (which is often 0.1m in Thickness)

to the rest:

Its calculated all the same way, as you note at the first side of the thread here, there is a figure of compare PIOMAS, Cyrosat2 and this product

greets


2
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: February 05, 2020, 09:50:32 PM »
Hi Jim,

Yes i also done a new script which allows to estimate volume direct to sea ice concentration, thickness and the area of the grids, results looks like this



the only thing i think about is to add is again the nrt data, but analysis is just 2 weeks behind so for that, i think it must not

3
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 29, 2020, 06:23:33 AM »
Update + change from Exel to "R" + change from NSIDC to AMSR2



now include the most recent volume of the "lines"

4
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 21, 2020, 06:10:50 PM »
Update on Volume


5
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 12, 2020, 07:38:06 PM »
Hope that makes it clearer:

6
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 12, 2020, 05:57:29 PM »
Here the Histogramms:

09.01.2019

09.01.2020


In 2020, SIT above 3m not exists

7
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 12, 2020, 11:43:14 AM »
In other words:

mean thickness at this date:

2019: 1.137332m
2020: 1.000787899m

while extent is nearly the same

9
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 12, 2020, 08:22:15 AM »
Update until 9.01

10
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 05, 2020, 09:30:55 AM »
With PIOMAS

11
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 03, 2020, 02:30:57 PM »
Update on SIV (to 30.12.2019)

12
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 03, 2020, 11:50:58 AM »
First of all, happy new year @ all

Nxt Part, SMOS at Melt-Saison:

First some notes:

1) SIT below 5cm is cut out, because there sometimes errors in the mapping at these low SIT
2) Its from 15. Apr to 1.09 Sep 2011-2019
3) SIT= Sea Ice Thickness
4) SIE = Sea Ice Extent

Some claims:
As often told, SMOS is not a physical use of SIT in the melt saison because of melt ponds cause interference which indicate the ice is very low in thickness, on the other hand, we can use this to claim, if SMOS SIT is very low at the begin of melt saison, its build up very much melt power, in other words, it preconditioning the outcome to september SIE.

Thats what i think i found in my analysis.. anyway some figures:

2019,2012 vs mean 2011-2018


Scattern Plot SMOS SIT(1.06 bis 15.07) vs. SIT (NSIDC September)


One more thing: If correlation is used for SMOS SIT after 15.07 the correlation gets near to 0 which also would imply the claims above

13
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 27, 2019, 06:05:44 PM »
Also to note, as thicker the ice gets, as greater becomes the uncertainy of
the measurement. Here Scatterplot for the Mean of 2011-2018:
SIT= Sea Ice Thickness
SITU=Sea Ice Thickness-Uncertainy



14
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 25, 2019, 02:01:31 AM »
Update to 21.12


@gandul
Nxt weeks i am most time at holiday, would make nxt up-to-date comparison in early january

15
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 19, 2019, 04:59:50 PM »
Cery interesting, RW.  Conceptually, the depth of snow will increase as the Arctic warms, but the winter ice area (~= extent) is decreasing, so a stasis is possible. 

I was wondering somewhere if increased winter ice mobility would cause more frequent lead openings and thus more opportunity for snow getting blown into (onto?) the water.  But maybe this possibility is an order (or two) of magnitude below the big picture.

In the short period, (2011-2018) Trends

SISM:

Okt; -0.122Gt/y
Nov: -0.393Gt/y
Dez: -0.260Gt/y
Jan:  -0.452Gt/y
Feb:  -0.633Gt/y
Mar:  -0.870Gt/y
Apr:  -1.477Gt/y


Mean Snow Depth (MSD)

Okt; +0.07cm/y
Nov: +0.01cm/y
Dez: +0.11cm/y
Jan:  +0.06cm/y
Feb:  +0.04cm/y
Mar:  +0.11cm/y
Apr:  +0.09cm/y


Its a to short period for making any significant claim, but as the data would imply, loose of sea ice(could also be the leads or the drift of ice with very much snow) overcompensate increase snowfall that its turn out an negativ Trend of SISM

16
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 19, 2019, 02:37:47 PM »
Its also possible to make Sea Ice Snow Mass (SISM) for the arctic: ftp://ftpsrv2.awi.de/sea_ice/product/cryosat2/v2p2/nh/l3c_grid/monthly/

- Use Snow Thickness
- Use Snow Density
- Use NSIDC Extent

You get:


In other words, arround 190-200 Gigatonnes (Gt) Snow Mass every year on arctic sea ice, before melt saison beginns. This is quite stabile, havent though its that low variance

17
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 18, 2019, 08:00:25 PM »
And perhaps the Scattern Plots for Cyrosat 2 and PIOMAS for 2011 to 2019(april) mon_mean

PIOMAS vs. NRT SIV



Cyrosat2 vs. NRT SIV


No surprise, Correlation must better against Cyrosat2 because its related to it in main fraction, besides the infill from SMOS. Also to note, on higher SIV, products beginn to have larger variances

18
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 18, 2019, 07:47:12 PM »
It will be interesting to see over time how this product and PIOMAS compare over a whole year. Especially summer, when thin ice makes life so much more difficult.

The Problem is, from 15th April to 21 Okt there will no data be available, therefore its just only winter product.

Meanwhile in compare to PIOMAS (used the same way as decribed before) from 21th Okt to 1. Dez 2019:

19
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 18, 2019, 06:02:43 PM »
SIV to 15 Dez:


PS: Update will occour every week or so

20
Arctic sea ice / Near Real Time Sea Ice Volume
« on: December 18, 2019, 06:01:09 PM »
Hi,

I build up an Near Real Time Sea Ice Volume (NRT SIV) product based on merged data from SMOS and Cyrosat2. To make it very simple, i decide to use mean sea ice thickness(SIT) and extent(SIE) data from NSIDC, beside this, it would also be possible by grid by grid methode, but since in winter, sea ice concentration (SIC) has not much variance over the domain, its seem unlikely that much differences would occur.

First things first, some Explantion:

SIV:  Daily
SIT:  5 five-day trailing average
SIE:  5 five-day trailing average

Its because of the merged SIT is just in a 5 five-day trailing average format accessible, therefor its also used for SIE and the final product SIV. What does this mean?

SIV(5 Nov): SIT(mean(1-5Nov))*SIE(mean(1-5Nov))


Some Plots:


SIV 2011-2018


NRT SIV vs. Cyrosat2 and PIOMAS (Okt to May)



Open Points for Future:
- Uncertainy-Bads from merged SMOS-Cyrosat2
- Testing other SIE like Uni-Bremen
- Melt-Saison-Model

Data-Source:
ftp://ftpsrv2.awi.de/sea_ice/product/cryosat2_smos/v202/nh/ ->analysis_sea_ice_thickness CS2SMOS merged sea_ice_thicknes
https://nsidc.org/arcticseaicenews/sea-ice-tools/ -> ea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx -> 5 five-day trailing average

21
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: December 18, 2019, 02:52:27 PM »
Thank you, Random_Weather. That looks quite appropriate for this thread, and very nice, imho.

I don't know what they're paying the folks maintaining this thread, but it's not enough!

The thing is, volume is much better then extent for the state of arctic sea ice, an NRT SIV (Sea Ice Volume) product based on observation is in my opinion a much more better way to isolate winter effects on it.

Remember the autumn 2016 with the very very low extent and very high temperature anomalies? Its not very much effects SIV (i think because of compaction due to drift from atlantic side)

Here in compare to 2012-2013 Refreeze Saision

22
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: December 17, 2019, 04:36:18 PM »
For those who may interest i, i made up an NRT Sea Ice Volume Product(Based on SMOS and Cyrosat2), which will be Update here: (not every day but i think i will update every week or so)

https://twitter.com/Christi89994998/status/1206153596737339392

To 14 Dez:

23
Arctic sea ice / Re: 2019 vs 2012
« on: August 11, 2019, 06:51:58 AM »
Neven,

Thats very easy, you just need to download: https://www.giss.nasa.gov/tools/panoply/

I wonder that most people here dont know about?

24
Arctic sea ice / Re: 2019 vs 2012
« on: August 10, 2019, 01:29:48 PM »
For some Folks not uninteresting


Data: ftp://ftp.remss.com/sst/daily/mw_ir/v05.0/netcdf/ (need for registry)
Red: 2019 warmer
Blue: 2019 cooler


https://seaice.uni-bremen.de/data/amsr2/asi_daygrid_swath/n6250/netcdf/

Red: 2019 more SIC
Blue: 2019 less SIC

25
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 03, 2019, 04:06:16 PM »
"2012 is the front runner as regards area again."

Its all of source you use: http://data.meereisportal.de/maps/latest/area_n_en.png Area here 6.34 Mio km^2 and for now the lowest on record

26
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 06:01:44 AM »

27
Arctic sea ice / Re: The 2018 melting season
« on: May 14, 2018, 07:27:39 PM »
jdallen,

Correct, GFS is strongly warm biased with time, since years i watch this, therefore i think its an issue with snow cover..

also see: http://www.karstenhaustein.com/reanalysis/gfs0p5/ANOM2m_arctic/verification/ANOM2m_bias_past07_arctic.html

to the +168h forecast, there is a massive warm bias to the past 7 days

Also evident over the full northern hemisphere: http://www.karstenhaustein.com/reanalysis/gfs0p5/ANOM2m_mollw/verification/ANOM2m_bias_past07_mollw.html

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