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Messages - BornFromTheVoid

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Arctic sea ice / Re: The 2020 melting season
« on: May 11, 2020, 11:53:30 AM »
The 850 hPa temperature is somewhere away from the ice. I'm not sure of the altitude, maybe someone with more knowledge than me can provide that.

But it is the temperature adjacent to the ice that is going to impact the ice, not the temperature 1,000 feet above sea level. For the benefit of the lurkers who are reading the thread, I think it's useful to kick the tires and questions some assumptions about the magnitude of the current events.

The heat coming into the Chukchi and ESS and the high winds pushing ice through Fram is quite significant and easily understandable and acceptable. No problem.

Maintaining heat over ice for a very long distance over ice and delivering it to the surface of much of the CAB where it can impact the ice in May is a completely differently animal. Skepticism of this is healthy from a scientific perspective.

Surface air temperatures over the ice are held close to a 0C maximum due to the latent heat of fusion of ice. This is quite apparent each year on the DMI 80N temperatures. For that reason, using something like the 850hPa temperature (or the less common, 925hPa value) is useful for assessing the relative heat mass over the ice. It's far from perfect, and temperature inversions, fog and such will add more complications, but much of the time in summer, 850hPa temperatures are more useful than surface temperatures.

Consequences / Re: Global Surface Air Temperatures
« on: October 15, 2019, 01:30:42 PM »
2nd warmest September on record according to the JMA

8 warmest Septembers all in the last 8 years.

Consequences / Re: Heatwaves
« on: July 26, 2019, 04:42:23 PM »

Consequences / Re: Heatwaves
« on: July 25, 2019, 07:33:41 PM »
I think the Asian economies are heading towards recession (even if fake China numbers don't show it), and this may have to do with aerosol %s dropping? I can't think of another explanation for Paris beating the 1947 record by 5F.

The Met Office did an interesting live video today discussing the current heatwave, the dynamics and the role of climate change.

At about 16 mins in they mention that northern Africa has warmed about 2C over the last century, and this is where the air for the heatwave is originating, hence the ability to smash records.

Arctic sea ice / Re: The 2019 melting season
« on: July 21, 2019, 10:42:10 AM »

In spite of what the weather models sometimes report, the actual temperatures in the northern CAA have been very warm over the past several days.   As discussed in previous posts, on July 14, 2019 the weather station at Alert, Nunavut hit 21C the warmest temperature ever measured north of 80 degrees Lat. 

A team of field researchers just wrapped up a 2 week trip on Axel Heiberg and reported widespread permafrost melting.  One of the researchers, professor Gordon Oz Osinski, said “in the 20 yrs since I started fieldwork in the Arctic I’ve never had such a long stretch of sun & temperatures in the teens [C].”  To find the thread, open Twitter and search #AxelHeiberg2019. 

Below is the link to the gif showing the permafrost melting.  It is definitely worth a click.  Pretty incredible sight when you consider that is happening at 79.8 degrees north latitude!

I think the crack that has opened (for a few weeks now) north of the CAA will likely be persistent, and could be significant this year.

What you're seeing in the video is likely part of what's called a thaw slump. While the number of them has increased quite dramatically in the Arctic over the last few decades, they are also just a normal occurrence in many paraglacial landscapes and have occurred in the Arctic for millennia.
They happen when layers of thick buried ice get exposed to the air. This can be by erosion from waves, rivers, or from things like heavy rain, which can cause the surface permafrost to detach. When the ice melts back, the soil on top slides down, mixes with the melt water and forms large flowing mud lobes at their front.
Here's 2 examples from my own fieldwork in 2017

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 10, 2019, 05:15:43 PM »
Neven, the daily extent drops show two consecutive double-century drops. Is the latest one a record? (Graph from Alphabet Hotel above)

Consecutive double centuries happen every now and then. The most recent was July 27th to 29th last year, with with drops of 211k and 253k.
2014 had one too, between the 27th and 29th of June, with 228k and 275k

Consequences / Re: The Holocene Extinction
« on: July 10, 2019, 12:15:51 PM »
Breaching a 'carbon threshold' could lead to mass extinction

Daniel Rothman, professor of geophysics and co-director of the Lorenz Center in MIT's Department of Earth, Atmospheric and Planetary Sciences, has found that when the rate at which carbon dioxide enters the oceans pushes past a certain threshold—whether as the result of a sudden burst or a slow, steady influx—the Earth may respond with a runaway cascade of chemical feedbacks, leading to extreme ocean acidification that dramatically amplifies the effects of the original trigger....

...What does this all have to do with our modern-day climate? Today's oceans are absorbing carbon about an order of magnitude faster than the worst case in the geologic record—the end-Permian extinction. But humans have only been pumping carbon dioxide into the atmosphere for hundreds of years, versus the tens of thousands of years or more that it took for volcanic eruptions or other disturbances to trigger the great environmental disruptions of the past. Might the modern increase of carbon be too brief to excite a major disruption?

According to Rothman, today we are "at the precipice of excitation," and if it occurs, the resulting spike—as evidenced through ocean acidification, species die-offs, and more—is likely to be similar to past global catastrophes.

"Once we're over the threshold, how we got there may not matter," says Rothman, who is publishing his results this week in the Proceedings of the National Academy of Sciences. "Once you get over it, you're dealing with how the Earth works, and it goes on its own ride.

The Paper itself

Characteristic disruptions of an excitable carbon cycle

The history of the carbon cycle is punctuated by enigmatic transient changes in the ocean’s store of carbon. Mass extinction is always accompanied by such a disruption, but most disruptions are relatively benign. The less calamitous group exhibits a characteristic rate of change whereas greater surges accompany mass extinctions. To better understand these observations, I formulate and analyze a mathematical model that suggests that disruptions are initiated by perturbation of a permanently stable steady state beyond a threshold. The ensuing excitation exhibits the characteristic surge of real disruptions. In this view, the magnitude and timescale of the disruption are properties of the carbon cycle itself rather than its perturbation. Surges associated with mass extinction, however, require additional inputs from external sources such as massive volcanism. Surges are excited when CO2 enters the oceans at a flux that exceeds a threshold. The threshold depends on the duration of the injection. For injections lasting a time ti≳10,000 y in the modern carbon cycle, the threshold flux is constant; for smaller ti, the threshold scales like ti−1. Consequently the unusually strong but geologically brief duration of modern anthropogenic oceanic CO2 uptake is roughly equivalent, in terms of its potential to excite a major disruption, to relatively weak but longer-lived perturbations associated with massive volcanism in the geologic past.

Arctic sea ice / Re: The 2019 melting season
« on: July 09, 2019, 10:08:51 AM »
Judah Cohen appears to be anticipating a gradual shift towards a neutral or slightly negative AO for the remainder of the month (as opposed to more strongly negative in recent weeks), so this suggests average or slightly above average surface air pressures generally across the Arctic ocean.
However, he is also suggesting that the NAO will remain in its negative state, which means higher air pressure around Greenland.

Looking at the anomaly charts for geopotential height, which you can roughly take as a guide to surface pressure patterns, high pressure remains around Greenland and stretching back towards the Beaufort sea, with low pressure across the Eurasian side of the Arctic.

6-10 day

11-15 day

Rather than a general period of storminess, this suggests a switch to a more dipole like patterns, which a chances of some depressions around the ESS, Laptev and Eastern side of the central Arctic ocean.
While it might not bring the exceptional heat the last 2 months, the potential for compaction and export from such a fractured pack is very high, and leaves little reason to suggest the weather will save the ice.

Consequences / Re: Global Surface Air Temperatures
« on: June 25, 2019, 01:06:58 PM »
Chart shows worlds temperature changes:

I made a somewhat similar graphic for the Central England Temperature earlier this year. It goes from 1659, top to bottom, is colour coded based on ranking, has all months and annual temperature for the last column, and includes the max and min data from 1878 onward. If you zoom in, you can see the dates and actual temperature for each month, as well as a few notable years and periods are highlighted

Consequences / Re: Weird Weather and anecdotal stories about climate change
« on: February 24, 2019, 02:52:03 PM »
18.8C today is the highest February temperature ever recorded in Wales

Possibly the warmest 24 hour minimum temperature record for the UK in February too

Consequences / Re: Weird Weather and anecdotal stories about climate change
« on: February 21, 2019, 06:12:51 PM »
Scotland broke it's February temperature record today with 18.3C, beating the 17.9C recorded in 1897.

Consequences / Re: Global Surface Air Temperatures
« on: February 16, 2019, 01:03:57 PM »
JMA have January 2019 as the joint 2nd warmest on record (with 2017)

1st. 2016(+0.52°C),
2nd. 2019,2017(+0.39°C),
4th. 2015,2007,2002(+0.29°C)

Consequences / Re: 2019 ENSO
« on: February 14, 2019, 06:04:17 PM »
Synopsis: Weak El Niño conditions are present and are expected to continue through the Northern
Hemisphere spring 2019 (~55% chance).

Consequences / Re: Global Surface Air Temperatures
« on: January 12, 2019, 12:01:37 PM »
So, is the 2018 data out? How did it finish?

4th warmest according to the JMA at least

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