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Messages - jai mitchell

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1
Arctic sea ice / Re: Stupid Questions :o
« on: May 26, 2017, 05:51:16 PM »

Why would you think that the IPCC might be "forgetting" some feedback in certain scenarios?


because 1/2 of the CMIP5 models do not include indirect effects from aerosols in their physical models and peer reviewed journal papers note that the impact of upper tropospheric cooling (and impacts to lapse rate) are not well understood and not included in their estimates.

The forcing applied to GHGs in the IPCC includes the effects of increased water vapor and Lapse Rate feedbacks and account for about 3/5 of this total forcing.

Confusing. You can find the definitions of radiative forcing (RF) and the new effective radiative foricng (ERF) from GHG's and aerosols in WGI, section 8.1 of the latest IPCC report. Box 8.1 is a useful summary.

The most common RF excludes any tropospheric changes, so  increased water vapor and Lapse Rate feedbacks are excluded by definition.
ERF allows a partial adjustment of temperatures and water vapor pressure but not of the sea surface temperature. Those adjustments are there because some of the aerosol effects are absorbing (black carbon) and indeed because of indirect effects. They are considered part of the forcing, not feedbacks. They do not include most changes in tropospheric temperatures, and the resulting water vapor and lapse rate feedbacks.

indeed, there has also been an adjustment of terms in AR5, away from the TAR and AR4.

If you want to read up on it (and thank you for your response and reference!) please see:

https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/drafts/WG1AR5_FOD_Ch08_All_Final.pdf
Section 8.1.1 page 119  line 41 on (quoted below)

In this chapter, we emphasize a forcing definition that accounts for the complicating effects of rapid responses on the radiation balance to allow quantification of additional forcing agents. This forcing is the adjusted forcing (AF), which is defined as the change in net irradiance at the TOA after allowing for atmospheric and land temperatures, water vapour, clouds and land albedo to adjust, but with sea surface temperatures (SSTs) and sea ice cover unchanged. This definition is chosen as one that (1) provides a good indication of the eventual climate response, (2) that allows evaluation of processes such as some aerosol indirect effects or so-called ‘semi-direct’ effects that influence climate but do not have an instantaneous forcing, and (3) that is readily calculated in model simulations with a comparatively small uncertainty range. Since the atmospheric temperature has been allowed to adjust, the AF would be identical if calculated at the tropopause instead of the TOA. Ideally, all known rapid responses would be included, but in practice calculations have to date largely been performed with models that have fixed composition and ecosystems (and hence neglect rapid responses of aerosols or ozone when calculating the response to CO2 forcing, and neglect changes in vegetation cover when calculating aerosol indirect forcing, for example). The conceptual relation between instantaneous RF and AF is illustrated in Figure 8.1 and it implies the adjustments to the instantaneous RF involve effects of processes that occur more rapidly than the time scale of the response of the global mean surface temperature to the forcing. The AF thus represents that part of the instantaneous RF that more directly contributes to the steady-state climate response.

Note: this is the draft, in the actual report the term "Adjusted Forcing" (AF) is changed to "Effective Radiative Forcing" (ERF)  (Box 8.1 that you cited) and these forcings do include the changes in troposphere and land (but not sea ice or ocean surface temperatures)

actual report box 8.1

Further review of Table 8.6 on page 696 and Figure 8.15 on page 697 shows that the reported radiative forcing is actually ERF -- as shown by the reported range of total anthropogenic radiative forcing in the table and shown graphically in the figure (see below)


2
Arctic sea ice / Re: The 2017 melting season
« on: May 26, 2017, 05:13:18 PM »
I am calling this here as "beaver force" after the Clovis period North Americans who believed that there were beavers underneath the Foxe-Laurentide Ice Dome that lifted it up to cause sudden, unpredictable (Jokullhaup) floods.


VeilAlbertKallio,

please see my response:

http://forum.arctic-sea-ice.net/index.php/topic,852.msg114814.html#msg114814

3
Science / Re: Early Anthropocene
« on: May 26, 2017, 05:12:52 PM »
I am calling this here as "beaver force" after the Clovis period North Americans who believed that there were beavers underneath the Foxe-Laurentide Ice Dome that lifted it up to cause sudden, unpredictable (Jokullhaup) floods.

VeilAlbertKallio,

I have not heard of any oral tradition history from the Clovis people, do you mean another tribe or group of peoples in the early americas?  do you have a source for this information?


4
Science / Re: Wattage from burning a ton of coal
« on: May 22, 2017, 04:56:46 PM »
a good thumbrule is that the amount of energy generated by combustion to produce a single molecule of CO2 is about 1/10,000th the amount of total accumulated energy produced over the life of that molecule in the earth's atmosphere until it is removed.

but that doesn't include the thermal efficiency of power generation which, depending on the method of combustion/generation can be as high as 40% and as low as 10%.

5
Arctic sea ice / Re: Stupid Questions :o
« on: May 21, 2017, 05:51:01 PM »
FYI I have received confirmation that these impacts are included in the models but that their uncertainty is high (as to how well they do it)

6
Arctic sea ice / Re: Stupid Questions :o
« on: May 21, 2017, 05:49:08 PM »

Why would you think that the IPCC might be "forgetting" some feedback in certain scenarios?


because 1/2 of the CMIP5 models do not include indirect effects from aerosols in their physical models and peer reviewed journal papers note that the impact of upper tropospheric cooling (and impacts to lapse rate) are not well understood and not included in their estimates.

The forcing applied to GHGs in the IPCC includes the effects of increased water vapor and Lapse Rate feedbacks and account for about 3/5 of this total forcing.

7
Policy and solutions / Re: Renewable Energy
« on: May 21, 2017, 04:48:49 PM »
An excellent presentation from Greg Wilson at the U.S. National Renewable Energy Laboratory on the trends and projections of PV cost reductions and what needs to happen to meet the IPCC targets.

https://www.youtube.com/watch?v=7CDPHxcnq4c

8
Arctic sea ice / Re: Stupid Questions :o
« on: May 20, 2017, 03:16:57 PM »
Aerosol Forcing

Aerosol forcing is a negative (cooling) effect that works to reflect solar radiation from the sun back out to space (global dimming).  It also cools the upper troposphere, lowering the effective height of the atmosphere (called the 'Tropopause') where it is present in abundance. 

Tropospheric aerosols, those pollutants like sulfur dioxide -- a product of burning coal and oil without clean air regulations -- like those conditions found in developing countries, typically last in the atmosphere only about 2 weeks.  The current IPCC range of forcing expected from human-caused aerosols is between -0.2 and -1.2 watts per square meter over the entire face of the earth.

If all human emissions of these cooling agents were suddenly removed we would experience a sudden warming of the planet.  This warming would raise the height of the Tropopause.  It would also lead to warmer temperatures that allow for slight increases in water vapor in our atmosphere.  Water vapor is a powerful greenhouse gas in its own right.  The warming that is expected directly from CO2 in the atmosphere is slightly less than 1/2 of the total warming that it produces because of the feedbacks of both increased water vapor in the atmosphere and the increased height of the Tropopause (called the 'Lapse Rate' feedback).

stupid question:
Does the IPCC estimate of forcing that is currently applied to the Earth from these aerosols also include the forcing reduction that would otherwise occur due to the water vapor and lapse rate feedbacks in their absence?

9
Arctic sea ice / Re: The 2017 melting season
« on: May 19, 2017, 12:35:22 AM »
Corner Alpha 2017

10
Consequences / Re: Wildfires
« on: May 17, 2017, 07:10:19 PM »
The entire Russian district of Siberia is under an official state of emergency.  It is only mid-may.

https://watchers.news/2017/04/29/massive-wildfire-engulfs-bubnovka-siberia-declares-state-of-emergency/


11
Policy and solutions / Re: Renewable Energy
« on: May 17, 2017, 06:42:04 PM »
but what happens to the planet when we suck the sun out of the air with solar panels. . .

12
Arctic sea ice / Re: The 2017 melting season
« on: May 17, 2017, 04:51:55 AM »
That's a great find guygee, I got to tell you guys, there is no other place I know of outside of university where such obscure questions can be answered and shared so readily!  keep up the great work guys!!!

 :) :) :)

13
Arctic sea ice / Re: The 2017 melting season
« on: May 15, 2017, 05:44:37 PM »
I wonder if we need a name for the day ~125 drop in DMI >80'N temp from above to below the mean.

this is present in 9 of the last 11 years (with exceptions in 2016 and 2008 (though an argument could be made for the latter).


14
Science / Re: The Science of Aerosols
« on: May 13, 2017, 07:35:31 PM »
this is good news to be sure, much more work must be done but this is good.

15
Consequences / Re: Conservative Scientists & its Consequences
« on: May 13, 2017, 05:33:57 PM »
 >:(
just for the record, I don't consider ^^^these^^^ people to be 'conservative scientists'  I see them as ideologically captured morons who are wittingly or unwittingly working as a fifth column in the war against humanity's survival.

16
Arctic sea ice / Re: The 2017 melting season
« on: May 13, 2017, 05:22:05 PM »
Charctic has been following 2007 melt quite closely for the last 2 months.

18
The expectation of a decreasing gap to low volume toward the end of the melt season is contingent on the previous observation of large volumes of land-fast multi-year ice on the northern Greenland coast. 

Similar to the 'effective ice-free convention' in SIE of < 1M km^2

This multi-year ice no longer exists in the way it was previously understood.

The assumption that later volumes of ice will be harder to melt is no longer supported by conditions in situ nor the physics of the environment.  However, at this stage, there are many larger impacts to projections of minimum volume and extent, through the coming melt period, than albedo.

for example, the early breakup of the Nares bridge. . .

19
Arctic sea ice / Re: The 2017 melting season
« on: May 12, 2017, 07:35:26 AM »

But, of course, there's always something happening.  ;)

5-day projections show a fairly significant low pressure system entering from the laptev that should bring rapid dispersal of the Barents pack.

20
Consequences / Re: 2017 ENSO
« on: May 12, 2017, 07:24:20 AM »
we have officially crossed into El Nino generation territory, if it persists. . .

21
Science / Re: Carbon Cycle
« on: May 11, 2017, 06:12:15 AM »
New study of Amazon river CO2 emissions shows that biosphere does not take up as much CO2 as once thought.

https://phys.org/news/2017-05-amazon-river-carbon-dioxide-emissions.html

Study finds Amazon River carbon dioxide emissions nearly balance terrestrial uptake
The results increase the most recent global estimates of CO2 emissions from rivers and lakes by almost 50%, with potentially huge implications for global climate policy


Paper here:  Henrique O. Sawakuchi et al, Carbon Dioxide Emissions along the Lower Amazon River, Frontiers in Marine Science (2017)
http://dx.doi.org/10.3389/fmars.2017.00076

22
Consequences / Re: Conservative Scientists & its Consequences
« on: May 10, 2017, 07:38:43 PM »
https://www.theguardian.com/environment/planet-oz/2017/may/09/planet-could-breach-15c-warming-limit-within-10-years-but-be-aware-of-caveats

Planet could breach 1.5C warming limit within 10 years, but be aware of caveats

A new study shows how a switch in a major climate system could accelerate global temperatures to a 1.5C limit, but some scientists are challenging the assumptions

This article describes a paper published this week that finds the Inter-Decadal Pacific Oscillation (IPO) has shifted to positive in 2014 and that its continued above average warming will lead to globally averaged surface temperatures reaching 1.5C before 2029.

Paper here:
http://onlinelibrary.wiley.com/doi/10.1002/2017GL073480/full
Trajectories toward the 1.5°C Paris target: Modulation by the Interdecadal Pacific Oscillation
Henley & King (2017)
DOI: 10.1002/2017GL073480

Abstract

Global temperature is rapidly approaching the 1.5°C Paris target. In the absence of external cooling influences, such as volcanic eruptions, temperature projections are centered on a breaching of the 1.5°C target, relative to 1850–1900, before 2029. The phase of the Interdecadal Pacific Oscillation (IPO) will regulate the rate at which mean temperature approaches the 1.5°C level. A transition to the positive phase of the IPO would lead to a projected exceedance of the target centered around 2026. If the Pacific Ocean remains in its negative decadal phase, the target will be reached around 5 years later, in 2031. Given the temporary slowdown in global warming between 2000 and 2014, and recent initialized decadal predictions suggestive of a turnaround in the IPO, a sustained period of rapid temperature rise might be underway. In that case, the world will reach the 1.5°C level of warming several years sooner than if the negative IPO phase persists.



See also: Paper's Author writeup here:  https://theconversation.com/global-warming-could-accelerate-towards-1-5-if-the-pacific-gets-cranky-77175

23
Arctic sea ice / Re: The 2017 melting season
« on: May 09, 2017, 06:00:42 PM »
This is a week out, so we can wait and see whether it verifies.  Rain smack in the middle of the Arctic seems unusual for mid-May.
     Note that the band of rainfall is forecast to track just poleward of a likely large area of melt ponding (less cloudy part toward left of image).


if you look at the normal >80'N DMI temperature trend, having a large portion of the CAB at above freezing surface temperatures would be, well, shocking to say the least.  I am pretty skeptical about this long-range forecast, though it does indeed fit the projections of GHG forcing and atmospheric circulation changes produced by global warming.


24
Arctic sea ice / Re: Arctic Image of the Day
« on: May 09, 2017, 06:32:52 AM »
Big block 2017 is no more - though it is a little difficult to tell through the clouds.

Cool. Although to equate this FYI with Big Block in 2016 is misleading.

big slab?

25
Arctic sea ice / Re: The 2017 melting season
« on: May 08, 2017, 02:51:56 PM »
Hyperion's posts/analysis have been very useful in this regard, as have others, in showing that the warming/increasingly ice-free Arctic is causing massive plumes of moisture, which inevitably intersect with mountaintops that ordinarily are snow-free by this time due to lack of moisture, above other factors.

Just a note,

The global Atmospheric Water Vapor maps indicate that the water vapor is coming from the tropics, that atmospheric water vapor has remained elevated since EL Nino and that circulation effects may by impacted by sea ice but, more likely, sea ice is being affected by global atmospheric circulation effects.

26
Arctic Background / Re: Iceland Holocene Temperature reconstruction
« on: May 06, 2017, 06:03:33 PM »
 ::)

This paper from lakebed samples shows that iceland was at most 2-3C warmer than the 1961-1990 values (and most likely around 1.5C) https://www.researchgate.net/profile/Peter_Langdon3/publication/223633044_Early_Holocene_climate_variability_and_the_timing_and_extent_of_the_Holocene_Thermal_Maximum_HTM_in_Northern_Iceland/links/02e7e531fe097c774d000000/Early-Holocene-climate-variability-and-the-timing-and-extent-of-the-Holocene-Thermal-Maximum-HTM-in-Northern-Iceland.pdf

however, it is also known that variations in the AMOC (gulf stream) current in the north atlantic produces large temperature swings.  It is these swings that have caused large variability in the Greenland ice core sample (and european temperature record).  Lukewarmist will often attach themselves to the intentional lies of paid deniers who present these regional variations as global proxies which they are obviously not. 

http://www.nature.com/nature/journal/v457/n7230/full/nature07717.html

Finally, the real issue is that this person you are talking about has a fundamental misconception of what effect the Milankovich cycles have on northern hemisphere temperatures.  That these cycles operate on scales that are thousands of years long and that at current solar forcing values, if it wasn't for early human CO2 and CH4 emissions, we would have plunged into a full ice age about 3,000 BC. 

instead we are set to jump above any previous warm period in the 800,000 year ice core record.

for more see:  http://environmentalscience.oxfordre.com/view/10.1093/acrefore/9780199389414.001.0001/acrefore-9780199389414-e-192

This is an excellent short video of Ruddiman explaining his work:  https://www.youtube.com/watch?v=96loo1w3SLY

Also the forum thread here:  http://forum.arctic-sea-ice.net/index.php/topic,852.0.html

27
The rest / Re: Presentation of Climate Change in News Media
« on: May 06, 2017, 07:11:59 AM »


mentions of climate change in news media

the spike in 2012 was coincident with hurricane sandy

The drop off in 2009 was the climate gate non-scandal after the run up to a vote on cap and trade.

the trend is quite clear, though I expect in recent years it has gone up quite a bit.


28
Consequences / Re: California weather extremes and climate
« on: May 06, 2017, 06:56:50 AM »
I am not advocating geoengineering though I sadly believe that it will be attempted in the next 15 years.

29
Consequences / Re: California weather extremes and climate
« on: May 05, 2017, 09:39:24 PM »
we already know that aerosols cool the earth that is the basic science of it and the basic science alone is sufficient to promote an argument for geoengineering. 

I am not sure what you believe my aerosol argument is.  In this case I am saying that there is very likely a large anthropogenic component that drove both the 2013/2014 and the 1975/1976 negative PNA periods that led to colder summers in the Arctic and hot/dry west coast weather.

I am also saying that, if this is the case, that our current schedule of reductions in fossil fuel emissions will not allow this long-term blocking to occur again (in the absence of actual geoengineering attempts - or tests)

30
Arctic sea ice / Re: Latest PIOMAS update (May)
« on: May 05, 2017, 05:45:31 PM »
I believe for several reasons that these years events were a statistical outlier over 4 sig.


"Black Swan" seems a bit too extreme.  The paleontological evidence seems to indicate a bit of stuttering before the actual climate switch.  This is also consistent with how natural systems generally tend to undergo a change of state in General Systems Theory.  Most of the time the system tends to choke a few times before flipping to a new state.  If you think about it, that is what happens with things like computer networks which are in the process of crashing -- they stutter and then fail.


Jim

http://forum.arctic-sea-ice.net/index.php/topic,729.msg112358.html#msg112358

31
Consequences / Re: California weather extremes and climate
« on: May 05, 2017, 05:44:42 PM »
My favorite chart, End-April volume, not even remarkable. A simple continuation of what looks like a linear trend, past a "plateau" that may have been random variability in hindsight.

This is good, however, it must also be suggested that the 2013 & 2014 'recovery' years were black swan events and are pushing the trend anomalously higher (straighter).  If these years effects did not occur and the volume gain during those years was removed then the trend would fall well below the long-term linear trend.

I believe for several reasons that these years events were a statistical outlier over 4 sig.

"Black Swan" seems a bit too extreme.  The paleontological evidence seems to indicate a bit of stuttering before the actual climate switch.  This is also consistent with how natural systems generally tend to undergo a change of state in General Systems Theory.  Most of the time the system tends to choke a few times before flipping to a new state.  If you think about it, that is what happens with things like computer networks which are in the process of crashing -- they stutter and then fail.

Jim

what you are saying is true to an extent, however we are not operating within a black box environment.  The 1976 and 2014 Gulf of Alaska blocking pattern has a distinct profile that is largely a result of varying upper troposphere aerosol loading.   I have been looking at this for a number of years now and the key indicator is that the Global Circulation Models (GCMs) used to model geoengineering (global dimming) show a strong and persistent blocking ridge in this region.

Therefore, while state-change activities are definitely happening, the drivers of specific systemic changes always have physical drivers.  It appears that the 2013/2014 cooler summers (and warmer winters in Alaska, drought in California and record snow levels on the east coast) are driven by regional shifts in high-temp process emissions of  aerosols (as happened in 1975 when Europe rapidly reduced their emissions but U.S. and Asia emissions were continued).

The 2013 event was similarly produced by reductions in U.S. emissions post 2007 crash but shifting this manufacturing to China who engaged in a command economy overproduction surge in 2013.

Without this knowledge this could appear to be a strengthening of natural variability under a shifting climate regime, but this is a black box analysis of a black swan event. 

This video has excellent analysis from people who were not aware of this aerosol driver.

https://www.youtube.com/watch?v=on0QmcDFgrg

32
Policy and solutions / Re: Batteries: Today's Energy Solution
« on: May 05, 2017, 04:37:39 AM »
Regarding cycles, I wonder. 1200 cycles over 25 years is less than one cycle per week. However, I assume that the battery will be topped up more or less daily. So in terms of battery degradation, are 6000 cycles at 1/5 capacity the same as 1200 cycles of full capacity?


You are right. I confused cycles in a car, that can be one cycle every few days, with cycles in a house or micro grid which at current battery sizes and prices will probably have to cycle everyday. 

I think that the rule of thumb for battery degradation in Tesla's chemistry is that degradation happens at close to full charge and close to almost no charge. It also happens at high temps regardless of the state of charge. I don't think charging the batteries at 1/5 charge or 4/5 charge would make much of a difference in battery life. 5/5 or 0/5 would destroy them real quick.

I think it was Sigmetnow that posted a video that contained very good details about this. I can't find the post but this is the video that best explain Li+ chemistry and Tesla's approach to maximizing it:

https://youtu.be/5WpQh4kZ_MU

benchmark testing of batteries looks at full cycle charge/discharge for maximum battery stress and degradation.  This development indicates that a normal operating vehicle will have a greatly increased range at longer operating times.  Current operations of high-use vehicles, like the Tesloop company in Los Angeles shows that batteries with 200,000 miles and 85% degradation can still be sold on the grid-storage aftermarket for upwards of $15,000.   

33
Arctic sea ice / Re: Latest PIOMAS update (May)
« on: May 05, 2017, 12:48:03 AM »
My favorite chart, End-April volume, not even remarkable. A simple continuation of what looks like a linear trend, past a "plateau" that may have been random variability in hindsight.

This is good, however, it must also be suggested that the 2013 & 2014 'recovery' years were black swan events and are pushing the trend anomalously higher (straighter).  If these years effects did not occur and the volume gain during those years was removed then the trend would fall well below the long-term linear trend.

I believe for several reasons that these years events were a statistical outlier over 4 sig. 

34
Arctic sea ice / Re: The Fast Transition
« on: May 03, 2017, 05:49:56 PM »
Will a "Blue Ocean" event in September trigger positive feedbacks that will rapidly (e.g. a decade or so) lead to a seasonally ice free Arctic with blue ocean being the predominant state throughout the summer months?
These feedbacks would include:
- Albedo Effects (possibly mitigated by cloud effects)
- Reduced separation between the Arctic and Northern Hemisphere climate regions, allowing for greater amounts of heat transfer into the Arctic
- Greater level of storms and waves driven by open ocean (and heat contrast between ocean and land)
- Mixing of the water column in the absence of a thick ice cover, bringing up deeper, warmer water to the surface

With the extra heat taken into the open waters during Spring/Summer being vented into the atmosphere in the Fall/Winter months, will the freezing season be significantly reduced (i.e. less and less FDD's) - reducing the ability of the ice to reform and thicken?

Could the Arctic then transition to near ice free year round as the increased energy taken in through the spring/summer, together with greater heat transport from the south, reduces the FDD's further and further?
- Thinner ice at the start of the melt season leads to greater warming from reduced albedo, leads to less FDD's, leads to yet thinner ice the next melt season.



http://onlinelibrary.wiley.com/doi/10.1002/2016GL070526/full

On the atmospheric response experiment to a Blue Arctic Ocean

Abstract

We demonstrated atmospheric responses to a reduction in Arctic sea ice via simulations in which Arctic sea ice decreased stepwise from the present-day range to an ice-free range. In all cases, the tropospheric response exhibited a negative Arctic Oscillation (AO)-like pattern. An intensification of the climatological planetary-scale wave due to the present-day sea ice reduction on the Atlantic side of the Arctic Ocean induced stratospheric polar vortex weakening and the subsequent negative AO. Conversely, strong Arctic warming due to ice-free conditions across the entire Arctic Ocean induced a weakening of the tropospheric westerlies corresponding to a negative AO without troposphere-stratosphere coupling, for which the planetary-scale wave response to a surface heat source extending to the Pacific side of the Arctic Ocean was responsible. Because the resultant negative AO-like response was accompanied by secondary circulation in the meridional plane, atmospheric heat transport into the Arctic increased, accelerating the Arctic amplification.


36
Policy and solutions / Re: US Wind Continues to Grow
« on: May 03, 2017, 04:55:39 PM »
This is a great lecture from one of the country's largest supplier of wind-generated electricity, talks about the economics, projections and where we are headed with wind and other renewables.  He has some very interesting ideas about offshore vs. onshore wind and I thought it very interesting that newer sited wind farms in the u.s. are approaching 50% capacity annually!


https://www.youtube.com/watch?v=2SXxJWUv-x4

37
Arctic sea ice / Re: The 2017 melting season
« on: May 03, 2017, 02:51:47 AM »
Mean annual volume export between 2003-2008 was 2,600 km^3

http://onlinelibrary.wiley.com/doi/10.1029/2009GL039591/full

I would be very surprised if that much ice was exported this year due to the anomalous thin ice (compared to the pre-2007 period)

38
I would be very shocked if this winter produced much more volume of ice than any year before.  In fact, i would be shocked if it produced THE SAME amount of ice as any year previously.  the export is simply not that great of a factor as a percent of total volume.

39
Policy and solutions / Re: James Hansen loves nuclear power
« on: May 01, 2017, 11:22:21 PM »
rboyd


In the Southwest gas is required on the coldest nights. Heat pumps are more efficient, as long as the ambient is >-10c.


> - 26C

http://www.fujitsu-general.com/us/residential/technology/xlth-low-temp-heating.html

Series features outdoor condensing units engineered to operate in temperatures down to -15ºF, lower than any other mini-split available today.

40
Consequences / Re: 2017 ENSO
« on: May 01, 2017, 02:24:13 AM »

41
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 30, 2017, 09:29:54 PM »
Good enough?

Yes, that is great!  JJA is a great predictor for Sept Min. (better than April)

42
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 30, 2017, 08:55:54 PM »
Just because residuals to the linear fit do not have a strong r^2 does not mean that there is a better/different model (than the linear fit with high direct r^2).  Find me a better fit curve with (significantly) higher residual coefficients.

43
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 30, 2017, 08:11:17 PM »
this is the correlation I am speaking of, as opposed to, you know, sea ice extent

44
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 30, 2017, 06:20:54 PM »
I would suggest that there is a very strong correlation between april volume max and september volume minimums.  the deviation in the post-2005 period between volume and extent metrics shows that, as thicker multi-year ice has been lost, the dynamics of arctic melt are changing.  This is also born out from the average thickness graph per year which is changing dramatically.  The inability to capture the changing nature of what sea ice extent is telling us, by assuming that what it says today compared to what it said in 1996 is a flawed use of the metric. 

It should be expected that as older, thicker ice volume is lost over the melt years that the behaivour of the melt will change.  It also stands to reason that Sea Ice Extent will show an inflated value over this period as ice disperses and is counted as coverage though it is only centimeters thick.  This is why i declare that sea ice extent is an anachronistic measure and its use as the primary method to communicate ice conditions in the September minimum is no longer appropriate.

It should be expected that sea ice extent will continue to lag behind volume until some critical threshold of volume is reached and then SIE will collapse quite suddenly (I expect this to occur sometime around 750 km^3).


45
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 30, 2017, 05:43:52 AM »
correlation between SIE and PIOMAS post 2005 are deviating from the norm.  R_W's post shows decadal averages and equates later decade's loss deviation with the deviation that was found with maximum >4 year ice in the early satellite period.  My point is that post 2005 the correlation value declines significantly between PIOMAS and SIE values.  This indicates that many studies that rely on SIE alone, (correlated to GMST and CO2 cumulative emissions) are understating the reality of actual ice conditions during the September minimum. 

Using CORREL or excel to derive r^2 values does not matter.  The values are the same.  and yes, if we are to continue this discussion we should transfer to a new thread.

46
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 29, 2017, 08:25:52 PM »
Bill,

I meant r^2 values for Sept. monthly avg values

For
r^2 NSIDC SIE SEPT. monthly avg. vs. PIOMAS SEPT. monthly avg 
1979-2016 =  0.895
1996-2016 =  0.871
2005-2016 =  0.546

This shows that as total volume is thinning post 2005 that the increase in fracture, ice mobility and the bias of extent analysis to overestimate coverage (i.e. brash ice) is invalidating SIE as the primary sept. minimum ice metric.   (it is not correlating)

47
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 29, 2017, 05:49:47 PM »
Just for a giggle, I did a quick correlation analysis between the PIOMAS September residuals and the NSIDC SIE September residuals. The value thus obtained for the correlation coefficient was +0.755

That value would be significant at the 99.9% level (p-value < 0.001) had there been only 16 data pairs, rather than the actual number, which was 38. Had there even been only 7 data pairs, such a correlation coefficient would have been significant at the 95% level.

The correlation is also going down over the last 2 decades.

48
It's not farfetched at all to imagine a year colder than 2014 happening in 2050 . . .

actually, yes it very very much is.


49
Policy and solutions / Re: Solar Roadways
« on: April 26, 2017, 02:58:13 PM »
France paved a road with solar panels

https://arstechnica.com/cars/2016/12/worlds-first-solar-road-opens-in-france/

World’s first solar road opens in France: It’s ridiculously expensive
Kilometer-long road cost $5.2 million to build.

it is one lane and provides enough power equal to the demand for street lighting.

but the economics of this is actually in the investment of long-life pavers, not energy.

A typical city street (2 lane) costs about $250,000 per km/lane to strip and resurface.  So if the panels last 20 years (doubtful) then a large portion of the cost is offset from maintenance savings.  If they are safer, provide self cleaning (snow) and some power then that would be additional savings.

I have always suspected that if this technology is to work it would be implemented on Route 66 in the southern united states.

50
Arctic sea ice / Re: The 2017 melting season
« on: April 26, 2017, 02:43:00 PM »
the average thickness graph is interesting and I have wondered for many years what it is actually telling us since it is really a function of two dynamic metrics, sea ice extent and volume.  I believe that your interpretation is correct that the loss of multi-year ice has skewed the distribution curve after 2007 and especially after 2012.  However, it should be noted that after a rapid collapse of sea ice extent, the average thickness would go up! Which on its face makes it kind of pointless to track, though there may be some interesting useful data there that I am not seeing.

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