Since I’ve been able to closely replicate one HadCRU3 gridcell from GHCN v2 data, it’s interesting to compare other HadCRU3 gridcells to GHCN versions. I’ve looked through a number of gridcells and each one has its own issues. Today, I’ll do a comparison of Malye Karmakuly, Novaya Zemlya, which we’ve discussed before, and the corresponding HadCRU3 gridcell. I’ll review some of the relevant data archives that I’ve located so far.
First, here is a simple comparison of the HAdCRU3 record for 72N, 52E against Malye Karmakuly. Where the records overlap, they are related, but for some reason the HadCRU information in the 1930s and 1940s is spottier than the GHCNv2 versions (I’ve required a minimum of 6 monthly values to create an annual average in these graphics.) In addition, the HadCRU3 version continues on to 2006, while the GHCNv2 version ends in 1989. So in this gridcell as well, the assertion by the CRU Freedom of Information officer, David Palmer, that the CRU version is available at GHCN appears to be false. The information at GHCN does not visually give an impression of a warming trend or “polar amplification”.
Figure 1. Top- HadCRU3 gridcell; bottom – GHCN v2 Malye Karmakuly versions
Obviously Jones is not using consistently the GHCNv2 version as archived. I’ve spent a fair bit of time scrounging through possible data locations and comparing different versions. Another Malye Karmakuly version is archived in connection with an archive of 59 Arctic sites for Overland et al (J Clim 2003) with the Malye KArmakuly data up to 2002 here.
This version is shown below, showing a rather pronounced downspike in 2002. What accounts for the difference? This is not discussed in HadCRU3 documentation.
Top- HadCRU3 version; bottom – overlay of OVerland et al 2003 version (to 2002) on GHCN v2 version (to 1989).
There is information from Russia on 233 sites here which is relevant for other locations, but Malye Karmakuly is not here.
There is a very large GHCN archive of daily max-min information here in which sites are coded by their WMO numbers. Malye Karmakuly (WMO- 20744) daily information is here http://www1.ncdc.noaa.gov/pub/data/ghcn/daily/gsn/22200020744.dly . This information for Malye Karmakuly goes from 1995 to Feb. 2007.
If you inspect the daily records for the past 10 years or so, you see many missing values. Were measurements more consistent during Stalinist times? Hard to say. The sporadic measurements don’t make these records look like magic bullets for the supposed lack of homogeneity in American and European records. I’m not saying that they are not usable for some purposes; however, the claimed quality control of Jones et al 1990 seems imaginary. Anyway from the daily information, I calculated monthly tmax and tmin averages (requiring a minimum of 14 measurements to take an average) and then applied the normals calculated from GHCN data to yield anomalies and thus the chart below.
There are some obvious differences between this information and the HadCRU3 series with HadCRU3 showing a stronger recent increase than I obtained from a plausible calculation from original data. I wonder what accounts for the difference. To tie down the differences, you really need to go through their code step-by-step with data as they actually used it. For now, all I can say is that one can derive a somewhat different looking time series using plausible methods on original data.
A final observation – again, there is no obvious “polar amplification” or even warming in this data since the 1930s. Yet Russia is a major center of recent measured warming. I’ll see if I can determine which gridcells are driving results in this area.