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Rascal Dog
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Mars perhaps had an ocean. There are formations that look exactly like wave cut benches around a basin in the Northern Hemisphere, along with deltas, all at close enough to the same current altitude. The simplest explanation is a water ocean.
Toggle Commented Dec 17, 2018 on PIOMAS December 2018 at Arctic Sea Ice
Based on the current day 90 ice volume from PIOMAS, and the median delta between day 90 and the minimum, things are very slightly better. Median - 3 SD is 0.262 10^ km^3, more than twice last month's projected minimum of 0.113 *10^3 km^3 3 SD is roughly 1 chance in a 100 below the trend lines. [img][/img]
Toggle Commented Apr 5, 2017 on PIOMAS April 2017 at Arctic Sea Ice
Based on PIOMAS volumes, an average change in volume from day 59 to the minimum volume would get the Arctic ice volume to as low of volume as in 2012. A very hot spring/summer (somewhat more than 2 standard deviations) would get to a volume consistent with a "ice free" Arctic Ocean. "Ice free" means some ice remains near Canadian islands and Greenland. I've never seen this possibility before.
Toggle Commented Mar 19, 2017 on Lowest maximum on record (again) at Arctic Sea Ice
Take the PIOMAS daily ice volume data: Find the day 59 data from each year. (last day for 2017 file) Find the minimum volume for a day each year. Calculate the yearly delta, day59-yearly minimum. Calculate the median and standard deviation for the series of yearly deltas. I calculate 14.64 and 1.27 for the mean and standard deviation. Day 27 for 2017 is 18.608 10^3 km3 2017 day 27 - mean ---------------------- = 3.1 standard deviation In other words, zero ice volume is about 3 standard deviations of this sample away from the current value. About a 0.3% chance. However, this is a simplistic computation, I can easily list a bunch of issues with it. An "Ice Free Arctic Ocean" isn't zero ice volume, as commonly defined, as some sea ice near Greenland and Canadian islands is expected to last for decades longer. The statistics are based on a normal distribution, and that isn't likely. PIOMAS is a model based on measurements, and might not be accurate. Ice isn't homogeneous. Melting isn't linear, both another way of saying the distribution isn't normal, but also pointing out that the melting delta increases over the sample. Looks to me based on this that there is a rough order of magnitude of a 1% chance of an ice free Arctic Ocean for at least a few days this summer. Not a basically zero chance, like all preceding years. Not a large chance at this time. To see the graph:
Toggle Commented Mar 18, 2017 on PIOMAS February 2017 at Arctic Sea Ice
"Self reinforcing" means to me positive feedback with a loop gain greater than 1. Nyquist stability criterion. This is ignoring methane, other factors. Double CO2 or 260ppm means about 2C to 5C warming. Yea, should use log of CO2, which would show less loop gain. But I want to do the math in my head and check with a calculator...Can not use Nyquist for non-linear. Past year temp went from 0.87C to 0.99C CO2 went up more than expected by a couple of ppm. So go around the loop. Increase in CO2 causes a temperature increase causes an increase in CO2. (5C/260ppm)*(2ppm/0.12C) = 0.32 Note that this is overestimated a bunch... But the answer is clearly well less than 1. If the CO2 increase was more than 6ppm per year higher than expected, would need to look closer.
Toggle Commented Feb 14, 2017 on PIOMAS February 2017 at Arctic Sea Ice
The climate wasn't warmer 3.5 thousand years ago, rather the reverse. The orbit of the Earth was slightly different. This slightly changed storm tracks, and feedback with greener/wetter/less dusty land getting more rain making the difference. Once the land starts to brown, the rain reduces making more for more dust, warmer surface and less rain. The Sahara has greened and returned to a desert multiple times.
Toggle Commented Feb 8, 2017 on PIOMAS February 2017 at Arctic Sea Ice
Past climates with Arctic Ocean ice free year round had CO2 levels in the range of 2 to 4 times postindustrial or higher. 500 to 1000 ppm or more. Turn of the century, maybe.
Toggle Commented Dec 7, 2016 on PIOMAS December 2016 at Arctic Sea Ice
I've noticed that relatives that are less than accepting of the whole idea of the climate changing have noticed this cruise. "The climate has changed a lot, hasn't it?" I'd like to say 'no duh', but instead find this a good teaching moment.
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Sep 12, 2012