Guest Post by Willis Eschenbach
A reader who posts under the name “tokyoboy” sent a link to a very interesting sea level record from the Japanese Meteorological Agency. It covers the period 1906–2010, and when I first saw it I thought they’d made some mistake.
So I got their data, and plotted it up. I also got the satellite records for the area. Finally, I got records of one of the sites that the Japanese used, but I obtained it from the PSMSL records. All of them agree very well, so I am forced to assume that there are no obvious errors in the Japanese records. Figure 1 shows the results:
Figure 1. Japanese sea level records. Two records marked “Japan” are from the citation above. They are averages of long-term records since 1906 (4 sites, blue line), and shorter-term records since 1960 (16 sites, red line). Satellite records (green, 1993-2010) are from the University of Colorado interactive wizard. Wajima records (purple, 1930-2010) are from the PSMSL.
You can see why I thought there was a mistake. Sea level around Japan rose steadily from 1906 to 1950. Then it dropped for fifteen years and bounced around until 1980. Since then it has risen again, but it is about 20 mm lower than it was in 1950.
Now, I can’t find anything at all wrong with the data. The satellite record agrees with the Japanese averages, as does the PSMSL record. So we have to assume it is accurate.
But it is unlike any record I’ve seen of the global average change in sea level. That global record climbs steadily over the century.
So I fear I have no great insight into what is going on. Over the last 80 years, the sea level in Japan was level, went up, went down, went back up, and now is not far from where it started.
I’m happy for suggestions and comments, as I’m in mystery over this one. It’s one of the great things about the climate, always more puzzles to solve.