AdjustmentGate–South America

By Paul Homewood

Before After

First it was the Arctic, then Australia, now it’s "Invent The Incline” in South America. It seems GHCN have been up to their tricks again.

However, as I am accused of not showing adjustments that produce a cooling trend, I can report that I have actually found a couple; Jujuy in Argentina and this one in the town of Arica, Chile! Take a good look at it. These adjustments seem to be like Sheffield buses – you wait ages for one to come along, then have to wait even longer for the next one! (There is also the odd case of San Luis where GHCN have adjusted the 1940 temperature up, but also adjusted the 1939 down, effectively cancelling out – temperatures have also been adjusted downwards from 1945 to 1973).

Don’t get too excited though, because it appears GISS have forgotten to make their homogeneity adjustment for UHI for them, despite the fact they have populations of 124000 and 88000 respectively.(More on this later).

As usual, I have gone back to 1940 to compare the unadjusted and adjusted temperatures. (Temperatures for 2010 are the same in both versions). Appendix A shows the results for all GHCN stations with records back to 1940. Out of 37 stations, 14 have past temperatures adjusted down, 20 remain unaltered and only 3 are adjusted up, giving, as a crude average, an artificial warming trend of 0.27C. Add this to the adjustments in the Arctic and Australia of 0.70C and 0.30C respectively and a pattern seems to be building up.

Finally, I have listed populations and indicated which are airport sites. As you can see, there are only four rural sites, i.e. less than 10,000, and two of these are based at airports. Do these stations show a different trend to the rest and have the urban sites been adequately adjusted for their UHI effect? We’ll take a closer look at this tomorrow.

APPENDIX A

Station Population

x 1000 Airport? Original Mean

Temp

1940 GHCN Adjusted

Mean Temp

1940 Adjustment Salta 260 Y 16.98 15.88 -1.10 Santiago 148 20.26 20.26 NIL Posadas 140 Y 20.86 20.86 NIL La Rioja 67 Y 18.95 18.95 NIL Catamarca 88 Y 19.40 19.40 NIL Ceres 10 Y 18.22 18.22 NIL San Juan 298 Y 16.63 16.63 NIL Pilar <10 16.76 16.76 NIL Parana 160 Y 17.57 17.28 -0.29 Rio Cuarto 110 15.49 15.49 NIL Jujuy 124 Y 17.92 18.22 0.30 Junin 42 Y 16.28 16.28 NIL Rivadavia <10 22.93 22.83 -0.10 Santa Rosa 52 Y 15.03 14.64 -0.39 Dolores 20 Y 14.80 14.80 NIL Mar del Plata 407 13.46 13.36 -0.10 Bahia 321 Y 14.78 14.78 NIL Bariloche 48 Y 8.84 8.24 -0.60 San Luis 71 Y 15.63 16.23 0.60 San Antonio <10 Y 15.23 15.23 NIL Esquel 15 Y 9.20 8.30 -0.90 Trelew 52 Y 13.53 13.53 NIL Comodoro 97 12.78 12.78 NIL Rio Gallegos 43 Y 6.68 6.68 NIL Ushuaia 11 Y 5.79 5.79 NIL La Paz 635 10.04 6.64 -3.40 Manaus 613 26.71 26.29 -0.42 Quixeramobin <10 26.99 25.99 -1.00 Salvador 1496 24.93 24.93 NIL Cuiaba 167 25.42 25.42 NIL Sao Paulo 7034 18.26 18.26 NIL Curitiba 844 17.00 17.00 NIL Arica 88 Y 19.11 20.01 0.90 Pudahuel 3615 Y 14.55 13.75 -0.80 Punta Arenas <10 Y 6.85 6.05 -0.80 Isla Juan <10 15.51 14.91 -0.60 Asuncion 388 Y 23.88 22.48 -1.40 AVERAGE -0.27

UPDATE

For the sake of completeness, I have added to the original list a few stations which don’t have complete records back to 1940.