Romm reports :
The Navy’s operational ice forecast system shows that his statement (as reported by Romm) is probably incorrect. Arctic Ice is thicker now than it was two years ago.
Disrupting the Borg is expensive and time consuming!
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Perish the thought that the Navy guy might have access to more up-to-date models, such as PIOMAS. You know, the successor to PIPS3, which was itself the successor to PIPS2.
PIOMAS – I remember now – the guys who forecast a record 3.7 minimum this summer.
PIPS2 is the Navy’s current “operational ice forecast system.”
the guys who forecast a record 3.7 minimum this summer
You keep claiming this. You’re wrong, and it’s been pointed out to you many times that you’re wrong. You’re wrong this time you’ve said it, you were wrong last time you said it, and you’ll still be wrong next time you say it.
3.7 was not the PIOMAS forecast, in fact so far as I can see no group ever had a forecast of 3.7. So far as I’m aware, you are referring to the Lindsay/Zhang forecasts from the SEARCH exercise, as archived here (June), here (July) and here (August). These were forecasts by Lindsay using a multiple-regression technique, initialised using a one-off input of PIOMAS thickness data. They did not use the oceanic /atmospheric models that are the core of PIOMAS. The page describing the methodology in detail is here.
In all, Lindsay made three forecasts, of 4.4 (June), 3.96 (July) and 4.0 (August). I’m not sure where you get 3.7 from, presumably this is some kind of ad hoc adjustment to account for the fact that the SEARCH forecasts were for NSIDC September average rather than IJIS single-day minimum values?
The actual PIOMAS forecasts, i.e. the forecasts that run the PIOMAS model forwards using estimated forcings and evaluate the forecasted ice cover, are the ones contributed by Zhang himself. These were 4.7 (June), 4.8 (July) and 4.8 (August). Substantially better than your own forecast, and made substantially earlier. Details of the forecast methodology are found here – note that this is on the PIOMAS website itself, while the Lindsay forecast page is not.
Details of both forecasting teams can also be found in the SEARCH outlook pages themselves (linked above). These too make it abundantly clear that Zhang’s forecast uses PIOMAS fully while Lindsay’s only uses it to initialise a simplistic regression.
Our method uses estimates of ice thickness from the PIOMAS coupled ice-ocean model as predictors for a statistical forecast of the Sea Ice Index mean ice extent in September.
End of July: Our prediction using model retrospective simulations from the month of July gives a forecast similar to last month’s: the best predictor is G0.4 (area with less than 0.4 m of ice) and the predicted extent is 3.7 +/- 0.3 million square kilometers. The R2 value for this predictor is still 0.84. Here is the diagnostic plot for this month:
http://psc.apl.washington.edu/lindsay/September_ice_extent.html
That shut him up Steve!
and i believe steven’s forecast was 5.1
Steve: Precisely.
They take a one-off reading of the thickness field, and use that as the basis for prediction using a multiple regression. They do not run the actual PIOMAS model forwards in time and use it to predict ice extent/thickness.
Do you actually understand the text you quoted?
How many angels CAN dance on the head of a pin? Do you understand that the PIPS data is fairly accurate?
http://stevengoddard.wordpress.com/2010/12/07/pips-correlation-vs-nsidc/
Peter Ellis says:
December 7, 2010 at 7:00 pm
such as PIOMAS
You say PIOMAS is reliable? You were being sarcastic, RIGHT? You had to of been.
And of course Romm or his oceanographer have been around for thousands of years to measure the ice.
If I remember correctly, there was quite a stir on WUWT last summer about Steven’s pips2 vs a RGates piomas. Guess who had a more accurate conclusion. Hint ( it wasn’t piomas).
PIOMAS was one of the worst.
Yes, a forecast of 4.8 relative to an actual value of 4.9 is clearly atrocious. Go and read the SEARCH exercises I linked, remembering that the PIOMAS forecast is the one by Zhang, not the one by Lindsay/Zhang.
The Navy is stupid. I guess they don’t teach them basic history
http://biocab.org/Holocene-Delta_T_and_Delta_CO2.jpg
I think the graph says it all. Climate “Optimums” existed several times before and after Christ. Ignore history and society is finished.
Ignore history? Alarmists are ignoring the present.
LOL!