HISTALP HISTORY - Early 1990s
The idea for a collection of quality improved, longterm instrumental climate data in the realm of the European Alps emerged in the early 1990s. It started within the climate division of the Austrian weather service (ZAMG) with processing the respective sources for monthly temperature means and precipitation totals (Böhm, 1992 , Auer, 1993) for the territory of Austria. Those two attempts already considered the basic requirements to an adequate dataset for climate variability and change studies. They tried to produce data being:
- LONGTERM (fully exploiting the potential of systematically measured data)
- DENSE (network density adequate in respect to the spatial coherence of the given climate element)
- QUALITY IMPROVED (outliers removed, gaps filled)
- HOMOGENISED (earlier sections adjusted to the recent state of the measuring site)
- MULTIPLE (covering more than one climate element)
- USER FRIENDLY (well described and kept in different modes for different applications)
The initial attempts in the early 1990s already met 1, 2 and 4 of the “HISTALP commandments”.
In order to meet no.1 by extending the series back into the late 18th (temperature, later also air pressure) and in the early 19th century (precipitation, later also cloudiness) the decision was drawn to concentrate HISTALP on monthly data for the time being.
No. 2 was adequately fulfilled through 58 temperature and 62 precipitation series. They were homogenised (no.4) and existing gaps were completed (no.3). Systematic outlier detection was not done at this stage.
N.5 was partly met (2 climate elements), as well as No.6 by keeping the series as “original” and as “homogenised” – the former being quality improved data according to the requirements of met-services and their predecessors, the latter through the application of relative homogeneity testing and adjusting (e.g. Peterson et al., 1998 , Auer et al., 1999 ). Still in the “Austrian period” Auer and Böhm, 1994 produced a first grid-mode through interpolation of the temperature and precipitation anomaly series to a regular 1x1 deg lat-long grid.