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Australian snow season start

By Gerg, on April 17th, 2015

Updated & corrected: Rationalised sub-intervals used for plotting; 1957 had a July zero

While we’re waiting for some real snow, I’ve updated the season start chart

. . . → Read More: Australian snow season start

It’s the stuff of charlatan rainmakers of old — when the weird dance doesn’t cut it, try firing some fancy pyrotechnics skywards and hope for a lucky cloudburst. Those pyrotechnics are not so very far from what Snowy Hydro has been up to for over a decade now, hoping to increase winter snowfall over our alps. But to what effect?

. . . → Read More: Cloud seeding and snow

Season 2015 snow depth prediction

By Gerg, on April 2nd, 2015

Updated…

Time to give this a try: the Spencers Creek season peak snow depth for season 2015 will be 141 ± 44 cm. . . . → Read More: Season 2015 snow depth prediction

Lowest and earliest Arctic sea ice maximum

By Gerg, on March 26th, 2015

The northern sea ice has now reached its seasonal maximum extent. This year’s is the lowest and earliest maximum of the satellite era (since 1979).

. . . → Read More: Lowest and earliest Arctic sea ice maximum

Trend significance

By Gerg, on March 21st, 2015

Updated: happy now; the words “hypothesis” and “null” do not appear (except to discard them).

There’d be no more abused tool in all of science than the linear regression “p-value” for trend significance. Don’t take my word for it; the problem is so severe that some technical journals have actually considered banning publication of p-values.

. . . → Read More: Trend significance

Spencers Creek snow depth prediction model - mark IV

By Gerg, on March 3rd, 2015

Updated: added residuals plot

I’m really impressed by this. I now have a snow depth prediction model that “explains” 50% of the variance in the Spencers Creek season peak snow depth record (midway between Perisher Valley and Thredbo, from Snowy Hydro). When you consider the vagaries of weather, snowfall, compaction, melt and weekly measurement, that really is a surprising achievement. I sure didn’t expect to get anywhere near it when I started out nearly a decade ago.

Volcanoes and snow

By Gerg, on February 18th, 2015

A precursor eruption of Pinatubo, June 1991 (USGS)

Large volcanic eruptions can affect global climate — ask the folk who starved to death in Europe in 1816, after the massive eruption of Tambora in faraway Indonesia the year before. Explosive eruptions often inject vast quantities of ultrafine material high into the stratosphere, where it spreads around the planet blocking incoming sunlight.

. . . → Read More: Volcanoes and snow

Sunspots and snow

By Gerg, on January 30th, 2015

Bear with me here. I come from a place with a long history of nutty sunspot-based weather prediction, so I’m well aware of the pitfalls. But our sun really is a very slightly variable star, and aspects of our climate do seem to very slightly vary with its output — particularly snow cover.

. . . → Read More: Sunspots and snow

The frequency of 'records'

By Gerg, on January 22nd, 2015

If you begin monitoring some variable thing over time, initially you’re going to see lots of new extremes — new record highs, for example. As your dataset grows, the frequency of new ‘records’ should decline sharply. If the overall system behavior is static, new records rapidly become very rare indeed, governed by the statistics of the variation. A feature of the 165-year long global temperature series in recent years is that new records highs have not been rare at all.

. . . → Read More: The frequency of ‘records’

2014 the warmest ... again

By Gerg, on January 19th, 2015

Update: Added note on Berkeley Earth.

Both the NASA GISTEMP and NOAA NCDC global temperature series have updated for December, confirming that the year just completed was once again the warmest on record. That’s since 1880 when those series start, but really since at least 1850 when the other instrumental series begin

. . . → Read More: 2014 the warmest … again

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