## Lines, Sines, and Curve Fitting 11 – more extrapolation

I’ve mostly been working through GISTEMP in this series, but the exp+sine results were interesting enough that I wanted to pause and look at both line+sine and exp+sine in all three data sets.

In order to show these on a common graph, I adjusted the CRU data up slightly.

delta <- (mean(noa) + mean(gis))/2 - mean(cru) delta [1] 0.1038117

**m3*x + b3 + A3 * sin(((x-B3)/T3)*(2*pi)**

m b A B T GIS 0.005725367 -11.16459 0.1050844 68.06118 58.15746 CRU 0.005734433 -11.28999 0.1351174 30.99897 59.23351 NOA 0.005459401 -10.61768 0.1300066 32.04425 59.21759

> cor(y3[,1],y[,1]) # GISTEMP [1] 0.9194656 > cor(y3[,2],y[,2]) # HadCRU [1] 0.9145043 > cor(y3[,3],y[,3]) # NOAA / NCDC [1] 0.9223988

**-a4/100 + b4/100 * exp((k4/10000)*(x-1880))+ A4 * sin(((x-B4)/T4)*(2*pi)**

a b k A B T GIS 39.39528 11.34487 158.5761 0.08123327 1857.690 66.71628 CRU 58.50143 17.07027 132.0417 0.11238451 1801.812 61.63521 NOA 37.78438 12.43439 150.1897 0.10528688 1863.281 62.17947

> cor(y4[,1],y[,1]) # GISTEMP [1] 0.9314415 > cor(y4[,2],y[,2]) # HadCRU [1] 0.9275221 > cor(y4[,3],y[,3]) # NOAA / NCDC [1] 0.938808

If the sine signal really exists in the physical system, the temperature increases we have seen over the last 30 years are going to slow considerable. **If the exp + sine is a realistic model, the global temp anomaly will only see an increase of about 0.1C – 0.2C over the next 20 years.** Compare this with an increase of about .3C over the last 20 years. **If the line+sine is a realistic model, global temp anomalies will drop over the next 20 years**

Exp + Sine increase from 2011 – 2030:

# GISTEMP: 2030 – 2011

(yy4[151,1] – yy4[132,1])

0.2005237

# HadCRU: 2030 – 2011

(yy4[151,2] – yy4[132,2])

0.09768462

# NOAA/NCDC: 2030 – 2011

(yy4[151,3] – yy4[132,3])

0.1239707

RON

“If the sine signal really exists in the physical system, the temperature increases we have seen over the last 30 years are going to slow considerable. If the exp + sine is a realistic model, the global temp anomaly will only see an increase of about 0.1C – 0.2C over the next 20 years. Compare this with an increase of about .3C over the last 20 years. If the line+sine is a realistic model, global temp anomalies will drop over the next 20 years”

Thanks so much for your work and your conclusions that I agree completely.

Ron, you rely “verify”!

You know RealClimate.org will not agree with your conclusions!

With all my best wishes Ron.

I accidentely posted on an old trhread here. I will repeat it here in case you miss it!

I have updated the multi-frequency approximation to HADCRUT3V.

I Have used your Idea of 2 frequencies+ trend the 2 frequencies + trend+TSI, and then all that + the other frequencies.

The 2 major frequencies are:

59.4167 years

103.5000 years.

TSI has no great effect

http://climateandstuff.blogspot.com

Mike