Comment 2113 is not me. Could you remove it – or ask the person who posted it to choose a different handle please?

If you have different relative drifts by season, then my guess is that, when combined with an anomaly procedure as hypothesized by Atmoz above, the combination would yield the seasonal pattern in differences.

I should have read a little more carefully!! Sorry for the confusion! FWIW I just plotted one over the other and did an eyeball, better if you just plot 1990’s and later.

Robb

You wouldn’t think it would be hard to subtract one time series from another, but somehow I messed it up

Well, you are in good company! I have a note on one of my early posts (before anyone read this blog) with an admission of a “very stupid mistake”. Yes… I’d subtracted wrong. The sorts of mistakes one makes with codes are different form the sorts one makes with hand calcs. I learned this long ago, but still make mistakes.

I now also sometimes plot nearly everything, have fiduciary “check” cells and do all sorts of stuff… and I still make mistakes sometimes.

I find the best way to find the errors is to click “publish”.. go do laundry, and come back in an hour. Mortification sets in… I fix and hope no one read! (On of the benefits of low readership is this can work. Unfortunately, leaving things as draft just doesn’t have the same effect as clicking “publish”. Also, to work you’d better not ping someone you are criticizing! )

I’m a bit confused as to your comment or possibly I wasn’t clear on what I was trying to say, but your plots above clearly show that from min to max in the one year cycle there is a change of ~0.2deg or greater in the land difference and ~0.1deg in the ocean difference. I have a plot of land diff and ocean diff on the same graph to show what I’m talking about but am unable to post.

Robb

In the bottom panel, the oscillations seem to be getting larger after 1995. That’s just by eye, but the first couple have magnitudes ~0.05 while the latter ones have magnitudes ~0.1.

I’ve included in the e-mail the old UAH data set. Just try plotting (new UAH) – (old UAH) for the overlap period. It is quite revealing.

Atmoz,

The change is clearest in current UAH vs. old UAH. Comparing to RSS just blurs the issue with a bunch of extra noise. I e-mailed a copy of the old file I used to Lucia, hopefully if she can track it down, she may be able to post it up. Otherwise the way back machine might have something – I downloaded the previous file on 13 Nov 2007.

I tried plotting the UAH cumulative sum for each month from Jan – Dec, starting at 1979. The cusums zero at year 20 as expected, so there is no change to the actual baseline date range. After year twenty, the cusums have a substantial positive gradient. The old UAH and RSS data seem to keep a consistent spread, the new UAH seem to diverge somewhat. Since the baseline is the same, I assume UAH have changed some detail of their processing which has had this side effect. I know they’ve been looking at the annual cycle (due to eccentricity of the earths orbit, etc) lately – e.g. this discussion at RPSr’s place – perhaps they have changed something predicated on that analysis?