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Original Temperatures: The Alps

Posted by Frank Lansner (frank) on 25th December, 2013
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Sources for temperature data:
1) Meteorological yearbooks Austria 1937-79, Slovenia 1949-79 (and more)
2) Statistical yearbooks Switzerland 1900-1957
3) Files required from DWD via Danish Newspaper
4) Tutiempo and ECA&D web sites
5) WWR
6) Web site by ZAMG: “HISTALPS”, + Online data from ZAMG.
7) GHCN raw v2 for certain stations in Italy and Switzerland.
8) French statistical yearbooks.

Fig 1 Austrian meteorological year books from ZAMG.

The availability of original temperature data for this work is fairly good for Switzerland, Austria and Slovenia, but For France and Italy original Alpine data so far is scarce.

Comments on Swiss temperature data.
Tutiempo vs. ECA&D check.

As for other countries like Spain, France and Poland, it is possible to show an ajustment of Swiss temperature data by making a comparison between Tutiempo and ECA online data. As explained in the ORI-TEMPS introduction, normally ECA presents newer temperature data versions than Tutiempo.

Fig 2

From around 2010 and onwards most Swiss stations have adjusted ECA datasets have around 0,6 K higher temperatures than the earlier Tutiempo versions.

Fig 3

The fact that the newer adjusted ECA versions shows extra heat trend in recent years is similar to many other countries analysed. For Switzerland the jump occurs in data from 2010, and the jump is around 0,6 K.

In this writing, mostly Swiss Tutiempo data will be used for the years 2010-12, not ECA.

Statistic year books.
Temperature data from a row of Swiss stations are published in the Swiss statistic yearbooks. These are available online as PDF´s 1891- 1957

These data confirms that ECA at least until 1957 do show original Swiss temperature data for all stations it was possible to analyse.

Austria / HISTALP

The Austrian ZAMG website “HISTALPS” ( presents their versions of Alpine temperature data online for Austria and several nearby areas.

Fig 4

This is how some of the Austrian temperature series are presented by ZAMG/HISTALP. All (not only the datasets shown here) show recent years warmer than for example the warm periods around 1930-60, typically 0,5 – 1 K or more.

For all areas analysed in the ORIGINAL TEMPERATURES project we see that temperature stations in valleys or locations in shelter of ocean air ( “OAS” areas) show little or no warming since the last warm peak 1930-50.
Is it true when ZAMG / HISTALP claim there are no such temperature stations with little or no heat trend since the last warm peak around before 1930-60 in the entire Alp area and surrounding areas?


Fig 5

Some temperature stations from Alpine OAS areas. HISTALP versions (red) vs. Original (blue) from the Austrian meteorological year books. HISTALP consequently show colder temperature trends than shown in meteorological yearbooks 1940-70.

Fig 6

In the 2 last examples - Sonnblick and Villacher Alpe –the stations are OAA (Ocean Air affected) since the locations are located on mountains peaks.
These areas typically have more heat trend in original data and HISTALPS rarely change such data much.
Fig 7

From the DWD-file of German temperature data (see ORI-TEMPS GERMANY) 2 temperature stations are so far inside the mountain area of the Alps that they too display the typical OAS (Ocean Air Shelter) patterns of strong cooling in the mid 20´the century.
Again, the Original Austrian temperature data for such sites appears to be supported.

Fig 8

Some nearby Swiss OAS valley temperature stations close to Austria show pretty strong temperature decline around 1950-80.

HISTALP on ZAMG web site also presents strongly adjusted temperature data from Hungary, Slovakia, Slovenia, Southern Germany, Switzerland and Northern Italy. See more in ORI-TEMPS HISTALP.

Estimating Alpine temperatures

Fig 9

In areas with numerous high peaks closely packed together, mostly the highest tops will be directly affected by ocean air. Also the edge of the mountain area will be exposed to ocean air. Therefore ocean air shelter areas dominate within mountain areas. Even some of the mountain tops can be in shelter of ocean air.

Fig 10

Around the Alpine massive mountain area (blue 1-7), there is a zone (yellow 1-4), the outskirts of the Alps. This zone has no shelter against air travelling longer distances, oceanic air. As always, the OAA (Ocean Air Affected) areas has a different temperature trend than the OAS (Ocean Air Shelter) areas, and as always The OAS areas has less heat trend since the warm period 1930-50 than the OAA areas.
Fig 11

Fig 12

I have divided lower Northern Switzerland into 2 areas 1a and 1b since I noticed a little difference in temperature trends. The valley stations of the 1a area are located near large lakes. Above the Lake stations, the 1a area.

Fig 13

And the 1b area..
Fig 14

The blue graphs (not lakes) show temperature levels in recent years somewhat similar to the 1940-50 peak while the lake stations have more heat trend. The extra heat trend for the lake stations, could it not be caused by City heat, UHI? Both the 1a and 1b stations have some urban data included, and notice that for the lake stations we don’t see much more heat trend over the full period. It’s specifically the heat around 1940-50 that seems supressed to some degree for the stations near lakes. This pattern is not a UHI patern, but more a pattern seen for ocean air affected stations. And more: The stations not near lakes, 1b, have trends much more similar to the other valley areas of the Alps, B2-B7, which makes the lake stations appear as outliers.

Enough of this little lake-experiment, let’s move on to the next Alpine areas:

Fig 15

Swiss temperature data from the Alpine mountain area dominated by the valley stations.
Fig 16

B2 have temperature trends rather similar to B1-not lakes. Thus, valleys within the Swiss mountain areas show similar trends to the larger valley of lower Northern Switzerland.
But how large a fraction of the mountain area is without exposure to ocean air – how large a fraction haven’t experienced much warming since last warm peak? As illustrated in fig 9, it would seem logical if most of the mountain areas belongs to the cold trended OAS zone.

Fig 17

4 stations from higher elevations, 1600-2100 meters altitude in the B2 Samedan is located in shelter of ocean air despite the high altitude.
Thus, elevation seems not to affect temperature trends much as long as the station is in shelter of ocean trends.
And as shown in ORI-TEMPS DENMARK, just 50-100 meter elevation differences are all it takes to lower temperature trends in the shelter area.

Fig 18

Fig 19

Now, B3, Tirol in Western Austria. For this area we use mainly the original data from meteorological yearbooks to show the strong dive in temperatures after 1940 (that for example the ZAMG site “HISTALP” seems to deny. Also 2 long temperature series from Southern Germany supports this strong decline.
For this area, B3, it seems that there is no net warming after the 1940 warm period.

Fig 20

For the next area, B4, I have a problem: There is no original data source beyond the years 1937-79 for any of these stations to my disposal (yet). However, it did seem as if the HISTALP data mainly adjusts data before 1975. Assuming that HISTALP adjust only data before around 1975, HISTALP suddenly appear like a much needed source of raw post 1975 temperatures. Thank you, ZAMG…
So, after 1979 stations Lienz, Rauris and Bad Gastein are continued using HISTALP data.
These datasets show different trends, but the overall picture is, that recent warm period still seems not much warmer than the 1940-60 warm period.

We can let ZAMG help us a little more, because they have all meteorological year books available on the net as online data from 1994 and forward. Data for Lienz, Rauris and Bad Gastein matches HISTALP in the period 1994-2012, so lets include ZAMG online data 1994-2012:
Fig 21

Now stations Kals, Zell am See, St Jacob and Kornat have been extended using ZAMG data for 1994-2012 for Again recent years show different trends. Different trends are not surprising because each site may have different exposure to ocean air.

Fig 22

Hereafter I will use the B4 average incl. ZAMG data 1994-2012 (blue) for the B4 area. It shows a little more heat trend than just the 3 HISTALP stations (red).

Fig 23

B4 with recent decades from HISTALP and ZAMG matches B1-B3 fairly well.

Fig 24

Using similar approach, here the B5 temperature trends..
Fig 25

And the B6 temperature trends..

Fig 26

The ZAMG site HISTALP use the city Klagenfurt in Southern Austria in this area. Klagenfurt original data (black line) has more heat trend than its neighbours. In addition it seems that the HISTALP team have lowered the pre 1953 data for Klagenfurt around 0,5 K. HISTALP (ZAMG) then ends up with the red graph for this area, a combination of adjustments and choice of Urban dataset adds around a kelvin in heat trend where the bulk of original data shows hardly any heat trend.

Fig 27

Here a close-up of Klagenfurt and some close neighbouring stations.

Fig 28

B7, Slovenia. HISTALP is considered an Urban outlier.

Fig 29

The Slovenian B7 area has temperature trend similar to Austrian B5 and B6.

Fig 30

At the edge of the Alpine mountain we have a ring of more warm trended temperature records where ocean air clashes with the mountains. But if we move just a bit further east, to the boarder of Hungary then again temperature records starts to show cooler trends. The B8 Area from Slovenia to Austria is somewhat similar to the Hungarian average dataset that covers most of Hungary (See ORI-TEMPS HUNGARIAN VALLEY).

Fig 31

Finally B9, the last area of ocean air shelter and cooler temperature trends. The lower area North of Vienna is located in shelter of ocean air from both east and west. I have only found data from these stations in the meteorological year books, and therefore some years are missing.
Fig 32

Fig 33

The Eastern edges of the Alp Mountains show heat trend. The latest decades are almost 1 K warmer than the warm peak 1940-50. In fact the “warm peak” 1940-50 is not that easy to see in these data.
This area also show that even though winds in Europe are mostly western, also mountain edges facing East seems to have some degree of typical ocean air warm trends with the 1940-50 warm peak rather small.
But, from what seas could this warm ocean temperature trend come from? In ORI-TEMPS THE HUNGARIAN VALLEY we see, that the Romanian Black sea stations have massive heat trends compared with Romanian inland stations that has no heat trend after the 1930-50 warm period. Thus, The Black Sea, The Caspian Sea and of course the Mediterranean Ocean seems to play an important role. At least I don’t know any other explanation for the Eastern Alp edge (Area S1) warm trend.

Fig 34

The Northern Alpine zones, Y2..
Fig 35

The Northern Alpine zones, Y3..

Fig 36

And the Northern Alpine zones, Y4..

Fig 37

Within the Alpine mountain area, here and there we have some stations with typical ocean air trends. Its mostly the high altitude stations, but also we have the Innsbruk stations. Insbruk is located in a very wide valley, and the valley is orientated east-west. This means that this valley is not really that good a shelter against typical westerly winds. In addition, Innsbruk may have produced some artificial heat trend due to city expansion since year 1900. Whatever the reason, Innsbruk temperature trends are similar to the typical ocean air affected sites.

Fig 38

The warm trended peak or mountain stations - Y5 - have a temperature trend similar to the warm trended stations in the edge zones Y1-Y4 surrounding the Alps. Possibly the mountain stations have a slightly colder temperature trend than the Y1-Y4 areas, but this might be due to the fact that the abundance Y5 on the highest peaks is small.

Fig 39

I will not make an overall average of Alpine temperatures because I cannot say precisely enough how large the areas of colder vs. warmer trends are. It is possible that the more warm trended areas of the Alpine higher elevations are underrepresented simply because most temperature stations are in the valleys where people live.

We can see though, that large parts of the Alps have seen just a quite small temperature increase since the 1940-60 warmer years. Especially the icy areas has experienced a warming that seems to be driven by ocean trends rather than the present day warmer heat balance on Earth over land. The still warmer ocean air may be a delayed response to the 1940-change in the heat balance we can see reflected in the land temperatures.
Since land temperatures without ocean air noise in data has not increased much since the 1940 warm period, then there is no reason to think that greenhouse gas warming has changed conditions for Earths heat balance much since around 1940.

Last changed: 25th December, 2013 at 17:12:15



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