Two adjoining grid boxes warming at ~ 2 degrees contain the cities of Irkutsk and Ulan Ude, populations 550,000 and 300,000 respectively, see Fig 10. This review compares the two cities with the small town of Zigalovo (pop 10,000) and the rural Barguzuin.
Figure 10 Grid Points 52.5 N-102.5E
& 52.5 N-107.5 E
Barguzuin also has a sister station just to the east with a shorter record. Another station with GHCN adjusted data is Kjahta SSW of Ulan Ude which has insufficient data to be of much use.
Zigalovo and Barguzuin make a sufficiently homogenous group with which to compare the two cities and data are available from the Jones 1994, GHCN and GISS. Figure 11 compares records from Barguzuin and while the Jones 1994 trend is nuetral, both GHCN and GISS opt for cooling of about 1 degree over the 90 years.
Figure 11
Turning now to Zigalovo in Figure 12, both GHCN and GISS find no trend over the 50 years but Jones 1994 uses only 40 years of data whichs has a warming trend of ~1.3 degrees over that time. This is not the first time in these reviews that Jones 1994 data is truncated relative to GHCN and GISS with an increased warming trend as the result.
Figure 12
The two cities are shown in Figure 13, both from Jones 1994 and we
can at once see where comes the warming in these grid boxes.
Figure 13
The writer can only state that with all that is known about the effect
of urban heat islands on temperature trends, the continued use of data
such as these to generate large area trends has to be scientifically indefensible.
This Lake Baikal study is another case of the rural stations telling a very different and cooler story than the cities and also the Jones 1994 data reporting warmer trends than the GHCN and GISS.
© Warwick Hughes, 2000
www.ozemail.com.au/~hughesw7
Warwick S. Hughes, 22, July, 2000