Jean S has written to me with another installment in our ongoing series about GISS conundrums. The puzzle starts with plotting the annual (Dec-Nov) GISS 1200 km anomaly map for the period 1991-2008 (here using 1961-1990 reference.) As you see, there is a Gavinesque red spot offshore Ecuador. Radio buttons generate plots at GISS here.
Figure 1. 1991-2008 1200 km anomaly
From the 250 km smooth (shown below), Jean S noted that the red spot could be pinned down to the Galapagos (more on this below.)
Figure 2. 1991-2008 Anomaly (250 km smooth).
Here’s Jean S’ conundrum. If you do precisely the same graphic – only using the Nov-Oct annual option, the red spot disappears. ???!!???
The data is at San Cristobal, Ecuador (Galapagos.)
Hansen et al 1999 stated:
there has been a real reduction since the 1960s in the number of stations making and reporting measurements.
I’ve observed on many occasions that I believe that there has been no “real reduction” in the number of stations “making: measurements – on previous occasions, we’ve offered to help NASA locate data from Wellington NZ and Dawson, Canada (and other locations where NASA has been unable to locate data from stations that report data on the internet.) Galapagos is another such situation. NASA only has measurements for 10% of the months since 1991 – with long and puzzling gaps between measurements. It’s sort of like the intermittent correspondence between Bronze Age emperors in Egypt or Assyria and Hatti, where years might pass between messages. Readers may reasonably differ as to whether Hansen would be more aptly compared to Hattusilis III or Ramesses II, to pick two of the more prominent such correspondents. I presume that the temperature measurements from the Galapagos arrived at NASA in sealed envelopes after a similar perilous journey.
Here is a plot of the anomaly data. You see the sparseness of the data after 1991. However, the royal messengers managed to get data for the big 1998 El Nino through to royal headquarters. Communications have been spotty since then, with only four measurements getting through enemy lines.
Figure 3. San Cristobal, Anomaly.