Support the Arctic Sea Ice Forum and Blog

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Topics - gerontocrat

Pages: [1]
I am starting this thread so these posts conform to the DMI Greenland Year September to August as in their website

Also,I will plonk GRACE-FO data on overall Greenland Ice Sheet Mass here (when I get it).

The Greenland 2019-20 melting Season thread is staying open, as there will be many year end reports coming out in the next few months.

Here are the daily & cumulative graphs for 4 September.

Arctic sea ice / Rain-On-Snow Events (ROS)
« on: September 04, 2020, 07:38:12 PM »
Don't know where to put this, and it is significant in tracking the threats to Arctic Sea Ice.
If anybody can find a good home for it.....?   Open Access
Trends and spatial variation in rain-on-snow events over the Arctic Ocean during the early melt season

Received: 28 Jul 2020 – Accepted for review: 25 Aug 2020 – Discussion started: 28 Aug 2020

Rain-on-snow (ROS) events can accelerate the surface ablation of sea ice, thus greatly influencing the ice-albedo feedback. However, the variability of ROS events over the Arctic Ocean is poorly understood due to limited historical station data in this region. In this study early melt season ROS events were investigated based on four widely-used reanalysis products (ERA-Interim, JRA-55, MERRA2 and ERA5) in conjunction with available observations at Arctic coastal stations. The performance of the reanalysis products in representing the timing of ROS events and the phase change of precipitation was assessed.

Our results show that ERA-Interim better represents the onset date of ROS events in spring and ERA5 better represents the phase change of precipitation associated with ROS events. All reanalyses indicate that ROS event timing has shifted to earlier dates in recent decades (with maximum trends up to −4 to −6 days/decade in some regions in ERA-Interim), and that sea ice melt onset in the Pacific sector and most of the Eurasian marginal seas is correlated with this shift.

There has been a clear transition from solid to liquid precipitation, leading to more ROS events in spring, although large discrepancies were found between different reanalysis products. In ERA5, the shift from solid to liquid precipitation phase during the early melt season has directly contributed to a reduction in spring snow depth on sea ice by more than −0.5 cm/decade averaged over the Arctic Ocean since 1980, with the largest contribution (about −2.0 cm/decade) in the Kara-Barents Seas and Canadian Arctic Archipelago.

Consequences / 2020 ENSO
« on: January 10, 2020, 05:29:50 PM »
A new year, a new thread, and the first monthly update from the US Climate Prediction Center

They used to talk about "the Spring Barrier" which reduces confidence in predictions. But not this time. Nevertheless, ENSO Neutral considered the most likely.

issued by
and the International Research Institute for Climate and Society
9 January 2020
ENSO Alert System Status: Not Active
Synopsis:  ENSO-neutral is favored through Northern Hemisphere spring 2020 (~60% chance), continuing through summer 2020 (~50% chance).

During December 2019, near-to-above-average sea surface temperatures (SSTs) were evident over the equatorial Pacific Ocean [Fig. 1]. Most SST indices increased in the past week, with the eastern Niño-1+2 and Niño-3 regions remaining near average (+0.1°C to +0.3°C), while the Niño-4 and Niño-3.4 regions were warmer at +1.2°C and +0.7°C, respectively [Fig. 2]. The recent increase in SST anomalies was partially driven by a combination of low-level westerly wind anomalies and the growth in positive equatorial subsurface temperature anomalies (averaged across 180°-100°W; [Fig. 3]). The latter indicates a downwelling Kelvin wave, which was evident in the above-average temperatures in the central and east-central Pacific Ocean [Fig. 4]. Over the month, westerly wind anomalies persisted over small regions of the western and eastern equatorial Pacific Ocean, while upper-level winds were near average over most of the equator. Tropical convection remained suppressed over Indonesia and east of the Date Line, and was enhanced to the west of the Date Line [Fig. 5]. The overall oceanic and atmospheric system was consistent with ENSO-neutral, though recent observations reflected a trend toward warmer conditions that will be monitored.

The majority of models in the IRI/CPC plume [Fig. 6] continue to mostly favor ENSO-neutral (Niño-3.4 index between -0.5°C and +0.5°C) through the Northern Hemisphere summer. For the December 2019-February 2020 season, the Niño-3.4 index is predicted to be near +0.5°C, which is consistent with the latest observations. The forecasters also favor above-average ocean temperatures to continue in the next month or two, but, in alignment with most model guidance, do not foresee a continuation over several consecutive seasons or shifts in the atmospheric circulation that would indicate El Niño. In summary, ENSO-neutral is favored through Northern Hemisphere spring 2020 (~60% chance), continuing through summer 2020 (~50% chance; click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).

This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA's National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts are also updated monthly in the Forecast Forum of CPCs Climate Diagnostics Bulletin. Additional perspectives and analysis are also available in an ENSO blog. The next ENSO Diagnostics Discussion is scheduled for 13 February 2020.

Climate Prediction Center
5830 University Research Court
College Park, Maryland 20740

Arctic sea ice / 2020 Sea ice area and extent data
« on: January 03, 2020, 08:42:47 PM »
JAXA ARCTIC SEA ICE EXTENT 12,474,725 km2(January 2, 2020)

- Extent gain on this day 43 k, 3 k LESS than the average gain (of the last 10 years) of 46 k,
- Extent gain in this freezing season to date is 8,510 k, 526 k (6.6%) MORE than the average last 10 years gain to date of 7,984 k.
- Extent is 7th lowest in the satellite record,
- Extent is 338 k more than 2017
- Extent is 20 k more than 2019
- Extent is 88 k (0.7%) more than the 2010's average.

- on average 81.1 % of extent gain for the the season done, 68 days on average to maximum.

We are well into the period when usually extent gains slow down - recently has seen some well above average gains.


Average remaining extent gain in the last 10 years from this date produces a maximum of 14.31 million km2, above the lowest in the satellite record by 0.43 million km2.
Ice Gain Outlook??

+ve SST (but diminishing) anomalies persist in parts of the Bering Sea, the southern end of Baffin Bay, and a patch south of Svalbard.

GFS says Arctic temperature anomalies range from +0.5 to +1.6 celsius over the next 5 days, 

Antarctica / Antarctic Ice Sheet
« on: September 07, 2019, 11:48:01 PM »
Why a new thread?

because stuff is coming out about the Antarctic Ice Sheet in general.
There is a major paper that I am still staggering through, and
it looks like GRACE-FO is becoming something like fully operational.

They are restarting placing files publicly available. More details tomorrow, but here is a taster. I did not realise until I processed the data the scale of the difference between East & West Antarctica

I am starting this thread so these posts conform to the DMI Greenland Year September to August as in their website

Also, if I ever get to see new GRACE-FO data on overall Greenland Ice Sheet Mass this looks like a good place to put it.

The Greenland 2019 melting Season thread is staying open, as there will be many 2019 reports coming out to the end of the year and beyond.

Consequences / Plant Life
« on: June 10, 2019, 07:48:18 PM »
With some trepidation, I open a new thread.

It is because I couldn't find somewhere to post the guardian article entitled
"‘Frightening’ number of plant extinctions found in global survey ".

But then again, while many reports emerge about the forests, not many reports surface in the media about the decline in what is such a major part of the web of life.

Will this thread survive or become extinct? Who knows.

‘Frightening’ number of plant extinctions found in global survey

Study shows 571 species wiped out, and scientists say figure is likely to be big underestimate

Human destruction of the living world is causing a “frightening” number of plant extinctions, according to scientists who have completed the first global analysis of the issue.

They found 571 species had definitely been wiped out since 1750 but with knowledge of many plant species still very limited the true number is likely to be much higher. The researchers said the plant extinction rate was 500 times greater now than before the industrial revolution, and this was also likely to be an underestimate.

“Plants underpin all life on Earth,” said Dr Eimear Nic Lughadha, at the Royal Botanic Gardens, Kew, who was part of the team. “They provide the oxygen we breathe and the food we eat, as well as making up the backbone of the world’s ecosystems – so plant extinction is bad news for all species.”

The number of plants that have disappeared from the wild is more than twice the number of extinct birds, mammals and amphibians combined. The new figure is also four times the number of extinct plants recorded in the International Union for Conservation of Nature’s red list.

Science / Satellite News
« on: June 09, 2019, 10:25:41 AM »
Starting this thread with a request - anyone any news on new satellites for NSIDC and JAXA sea ice data?

I am asking because the existing satellites are, I believe, somewhat long in the tooth. Copy of post in sea ice extent data thread below..
Quote from Gerontocrat

Quote from: Juan C. García on Today at 06:58:36 AM

Quote from: Rich on Today at 06:44:08 AM
Are there any plans to reduce the grid size?
There are always new satellites with better resolution. The question is if institutions like NSIDC are going to change the algorithm that they use to measure extent and take full advantage of the new instruments.

Nobody can go back in time and adjust the NSIDC data collected by the instrument on the DMSP satelliteS  to the higher resolution data collected by current instruments and maintain consistency in the record. That is why the graphs using higher-resolution data from the new instruments on the new satellites (e.g. from Wipneus) only go back a few years.

The much greater problem is the inevitability of the NSIDC record dating from 1979 ending. The satellite up there is years beyond its design life and the United States Air Force programme DMSP was killed by Mike Rogers in 2017. The last satellite is now in a museum somewhere.

I asked NSIDC a few months ago what the plan is for when this last satellite fails. The answer was along the lines of "under discussion". It will be a real shame if this unique record is cut short.

As Arctic Sea Ice Shows Record Decline, Scientists Prepare to Go Blind

Air Force unveils $500M satellite museum piece
And things are not much better at JAXA. JAXA’s GCOM-W1 satellite was launched in 2012 with the Advanced Microwave Scanning Radiometer 2 (AMSR2) on board.

Its design life was 3 to 5 years.

Policy and solutions / Water Resource Management
« on: January 19, 2019, 09:16:43 PM »
The only thread specifically about water is in "Consequences- Water Wars".
A thread about how humankind is, or is not managing water resources seems a good idea. 
Time will tell.

an example....
This study gives a really good look at the good, the bad, and the ugly sides of desalination and possibilities for the future. It also shows that we are talking big numbers.
The state of desalination and brine production: A global outlook

Apart from the problem of brine production (salt and other ooh-nasty trace elements being concentrated and dumped in the ocean (shown by the study to be underestimated), the study also shows that at the moment the cost limits the use of the fresh water produced to domestic and industrial use in relatively high income countries.

There is a BBC article based on this study at . It finishes on an optimistic note - we will see.
Concerns over increase in toxic brine from desalination plants
"There is an urgent need to make desalination technologies more affordable and extend them to low-income and lower-middle income countries. At the same time, though, we have to address potentially severe downsides of desalination - the harm of brine and chemical pollution to the marine environment and human health," said Dr Vladimir Smakhtin, a co-author of the paper from the UN University.

"The good news is that efforts have been made in recent years and, with continuing technology refinement and improving economic affordability, we see a positive and promising outlook."

Greenland and Arctic Circle / Greenland 2019 Melt Season
« on: January 13, 2019, 08:37:02 AM »

2019 MELT SEASON - 2018-2019 SMB SEASON As at 12 Jan 2019

Some dry days and wet days so far this year.

And for the next 5 to 10 days it looks like,
- no melt,
- below average precipitation,
- SMB balance year to date a bit more below average.

SMB = Surface Mass Balance, which excludes mass loss from calving that on average is greater than SMB gain in the year. i.e. usually Greenland loses mass every year.

GRACE follow-on data - where are you?

Arctic background / Arctic Background Data Library
« on: February 22, 2018, 09:38:06 PM »
With considerable trepidation, I start a new topic.

A lot of stuff we post is of long-term interest that should be kept, but gets lost into history as the seasons change and so do the threads, I don't know about you, but my PC is cluttered up and old, I am losing stuff already. So I suggest we need a place to put it, or at least the links. The ASI graphs are already safely locked away but accessible.

I found a site today that many of you probably know

It is the sort of data that is of long-term interest. An example is the 925hPa temperature history from 1958 to 2017, I had never come across before, which no doubt Zachary will keep going (automated already?)

If you use it, please note the title "Arctic Background Data Library" - i.e. for data, not opinion. no "near human extinction" diatribes).

A brief description of the data and the link to it (external or internal within ASIF) might be all that is necessary. I will be posting a few tomorrow.

End of message

Pages: [1]