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Sunday, May 11, 2008

A Fresh Look at NCDC Absolute Temperature- Part 1

Please refer to the notes on data source prior to downloading the JunkScience .csv files.


Like many people, I’ve examined temperature anomaly data and reexamined it until it seems to offer no new climate insight. NCDC Absolute data (Courtesy of JunkScience) is sure to hold correlations that aren’t visible in anomaly data.

In Figure 1.1, the first thing that stands out is the difference in the amplitude of the annual variations in land and sea surface temperatures. Next, the year-to-year variations in the minimum land surface temperature (LST) are greater that the total amplitude of sea surface temperature (SST).

Figure 1.1: NCDC Absolute – Land vs Ocean – January 1900 to March 2007

The combined land and sea data was added to Figure 1.2. http://i29.tinypic.com/iozy2h.jpg
Figure 1.2: NCDC Absolute – Land vs Ocean vs Land + Ocean – January 1900 to March 2007

And in Figure 1.3, SST data for the NINO3.4 region, which occupies a small portion of the global surface area, Figure 1.3b, was added to provide a comparison of its order-of-magnitude to the other indices.
Figure 1.3: NINO3.4 SST vs NCDC Absolute – Land vs Ocean vs Land + Ocean – January 1900 to March 2007

Figure 1.3b: NINO3.4 Region


For the following graphs, I employed EXCEL to extract the Annual Maximums, Minimums, and Averages of the monthly values in the Combined Land and Ocean data for each year, as illustrated in Figure 1.4, eliminating that cluster of spaghetti in the middle.

Figure 1.4: NCDC Absolute Annual Global Land + Ocean – Maximum, Minimum, Average – 1880 to 2007

The decreasing difference between annual maximum and minimum temperature is illustrated in Figure 1.5. Minimum temperatures rose at a greater rate than maximum temperatures.
Figure 1.5: NCDC Absolute Annual Global Land + Ocean – Max Minus Min – 1880 to 2007

The curve of the annual average of the monthly absolute global land plus ocean temperature values, Figure 1.6, is very similar to anomaly data graphs, with minor variations. The most notable of these is, the 2005 temperature value is higher than 1998.

Figure 1.6: NCDC Absolute Annual Global Land + Ocean – Average – 1880 to 2007

Annual maximum values in the global combined land and ocean temperature are illustrated in Figure 1.7. Compared to the Average curve above, the changes are minimized slightly. It too provides the typical changes in trend: the decrease from 1880 to 1910, the increase from 1910 to 1944, the decrease from 1944 to 1976, and the increase from 1976 to 2007. However, when compared to the linear trend line, the curve appears to be a natural oscillation with a span of 50 to 60 years.

Figure 1.7: NCDC Absolute Annual Global Land + Ocean – Maximum – 1880 to 2007

The curve of the annual Minimum data, Figure 1.8, is much more linear; that is, the multiple positive and negative trends are much less pronounced, and they may have shifted. In some respects, using the linear trend as reference, it’s relatively straight from 1890 to 2007, with a dip between 1960 and 1980.

Figure 1.8: NCDC Absolute Annual Global Land + Ocean – Minimum – 1880 to 2007

That dip in Annual Minimum Global Temperature correlates with the 1960 to 1980 drop in TSI associated with Solar Cycle 20. Refer Figure 1.9.
Figure 1.9: TSI

But how do I illustrate that correlation? Let’s try running linear trend data between the Solar Cycle maximums, in effect to connect them. Refer to Figure 1.10.http://i28.tinypic.com/zluur4.jpg
Figure 1.10: TSI and Maximum-to-Maximum Linear Trends.

Extracting the Maximum-to-Maximum Linear Trend curve and overlaying it on the Annual Minimum Land + Ocean data results in a reasonable correlation, better than I anticipated. Refer to Figure 1.11. To scale the TSI, I had to shift it by 1354.4, but note that it aligns without a multiplier, indicating a reasonably high climate sensitivity. The TSI curve ends in 2002, the last year of the maximum of Solar Cycle 23. http://i28.tinypic.com/2ept3qp.jpg
Figure 1.11: NCDC Absolute Annual Global Land + Ocean – Minimum vs Maximum-to-Maximum TSI - 1880 to 2007
The correlation of the two curves appears to infer that minimum annual global temperature is a function of maximum TSI, or a derivative thereof. Oceanic time lags and inertia could be used to explain the process.
“A Fresh Look at NCDC Absolute Part 2” will be finished soon.


Arnost said...


the first thing that stands out is the difference in the amplitude of the annual variations in land and sea surface temperatures.

I have tried to find the source of the data - but no luck yet... What the variation in amplitude (a range of some 10 degrees between Jan and July) suggests that the temperatures are for the nothern hemisphere (US maybe?), and not "global". You may want to check...

You are doing some very interesting things... All good stuff!



Bob Tisdale said...

Arnost: According to the JunkScience "'Global Warming' at a Glance" webpage:


"The same file states 'The global monthly surface temperature averages in the table below can be added to a given month's anomaly (departure from the 1880 to 2004 base period average) to obtain an absolute estimate of surface temperature for that month.' Which is precisely what we are doing with the global combined, global land and global ocean anomalies to derive the following, revised global absolute temperatures."

The NCDC table and statement JunkScience refers to is mid-page here:


The NCDC Table of Mean Monthly Surface Temperature Estimates (Deg C) from 1901 to 2000 lists the following. I added the differences.

Jan (2.8)
July (14.3)
Difference (11.5)

Dec (15.7)
July (16.4)
Difference (0.7)

Jan (12.0)
Jul (15.8)
Difference (3.8)


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