Spatial climate analysis in complex terrain : generation, evaluation and interpretation of gridded temperature and precipitation datasets for Austria

Modellierungs-, Reanalyse-, Monitoring- und Planungsaufgaben in der Klima(folgen)forschung wie Quantifizierung von Klimasignalen, Umweltmodellierung, Evaluierung regionaler Klimamodelle usw. erfordern flächendeckende Datensätze des beobachteten Klimas. Das Ziel dieser Arbeit ist die Entwicklung eines Gitterdatensatzes von Lufttemperatur und Niederschlag in 1-km- und Tagesauflösung für Österreich ab 1961.Die eingehenden Messreihen beschränken sich auf ein konstantes Stationsnetz. Für gebirgiges Gelände entworfene Interpolationsmethoden werden an die Besonderheiten der Physiografie und Stationsverteilung in Österreich angepasst. Bei der Lufttemperatur werden nicht-lineare Vertikalprofile mit der nicht-euklidischen räumlichen Repräsentativität von Beobachtungen verknüpft. Beim Niederschlag werden Klimafelder, basierend auf Kriging mit topografischen Prädiktoren als externer Drift, mit täglichen Anomaliefeldern, basierend auf Winkeldistanzgewichtung, vereinigt.Selbst in schwierigen synoptischen Situationen liefern die Ergebnisse plausible Muster. Die mittleren Interpolationsfehler sind bei der Lufttemperatur gering (ca. 1 K), beim Niederschlag aber beträchtlich (ca. 1,5 für Ereignisse 3 mm). Eine bedingte Verzerrung beeinträchtigt Auswertungen der Häufigkeitsverteilung des Niederschlags.Der Nutzen des Gitterdatensatzes wird durch die Abbildung der Trends von Klimaindizes dargelegt. So verringerten sich Häufigkeit (11 %) und Intensität (0.02 K/100 m) bodennaher Temperaturinversionen bemerkenswert. Dies hängt mit übermäßiger Erwärmung in niedrigen Seehöhen im Jänner, Oktober und Dezember zusammen.Die wesentlichen Neuheiten des vorliegenden Gitterdatensatzes (genannt SPARTACUS) bestehen in der Kombination von täglicher Auflösung und jahrzehntelanger Ausdehnung bei Schwerpunktlegung auf zeitliche Konsistenz, der Übertragung ausgearbeiteter Interpolationsmethoden auf Verhältnisse in Österreich und seiner tiefgreifenden Evaluierung zur Unterstützung sinnvoller Anwendung.Modelling, reanalysis, monitoring and planning tasks in climate (impact) research like quantification of climate signals, environmental modelling, evaluation of regional climate models, etc. require spatially comprehensive datasets of the observed climate. The aim of this thesis is to develop a gridded dataset of air temperature and precipitation at 1-km and daily resolution for Austria starting from 1961.Input measurement series are restricted to an invariant station network. Interpolation methods developed for mountainous terrain are adapted to specifics of the Austrian physiography and station distribution. For temperature, nonlinear vertical profiles are combined with the non-Euclidean spatial representativity of observations. For precipitation, climate fields based on kriging with topographic predictors as external drift are merged with daily anomaly fields based on angular distance weighting.The results provide plausible patterns even in challenging synoptic situations. The mean interpolation errors are small for temperature (ca. 1 K) but considerable for precipitation (ca. 1.5 for events 3 mm). A conditional bias affects analyses of the frequency distribution of precipitation.The utility of the gridded dataset is demonstrated by mapping trends of climate indices. For example, the frequency (11 %) and intensity (0.02 K/100 m) of near-surface temperature inversions have decreased remarkably. This is related to a warming anomaly at low altitudes in January, October and December.The key novelties of the present gridded dataset (called SPARTACUS) are the combination of daily resolution and multi-decadal extent with focus on temporal consistency, the transfer of elaborate interpolation methods to conditions in Austria and its extensive evaluation to support reasonable application.Hiebl Johann, Mag.rer.natZusammenfassungen in Deutsch und EnglischKarl-Franzens-Universität Graz, Dissertation, 2018OeBB(VLID)294591

Temperature inversions in Austria in a warming climate – changes in space and time

Alpine valleys and forelands are prone to near-surface air temperature inversions, particularly during the cold season, that affect both environment and society through altered values of frost occurrence, snow cover duration, incoming radiation, pollutant dispersion, etc. In order to examine trends in inversion occurrence and intensity across Austria for the period 1961–2017, we exploit a gridded observational dataset of daily minimum temperature. On average over the 1961–1990 period, inversions occur on 21 ± 5 % of all days (mean value and area standard deviation) with typical intensities (vertical temperature gradients) of 0.31 ± 0.06 K/100 m, magnitudes (vertical temperature contrasts) of 1.9 ± 0.4 K and layer thicknesses of 550 ± 80 m. We present regional, seasonal and decadal variations in inversion parameters. Inversion formation is facilitated by below-average temperatures in winter and high air pressure in autumn in particular. The main result is that the occurrence of an inversion day has become less likely(−11 ± 17 %) over the period 1961–2017, accompanied by decreases in both intensities (−0.02 ± 0.03 K/100 m) and magnitudes (−0.3 ± 0.2 K). Changes are statistically significant in southern and central Austria. The average thicknesses of inversion layers, however, remained largely unchanged. Inversion decline is seasonally most pronounced in October, December and January (in contrast to November and February) and may regionally have induced excessive warming at low altitudes in these months

Austrian Norway spruce provenance test 1978 - list of populations (provenances) and climatic details

All tested provenances and according climatic details are given. Climate variables were provided by the Central Institute for Meteorology and Geodynamics, Vienna, Austria. For details see DOI: 10.1016/j.foreco.2012.01.03

Austrian Norway spruce provenance test 1978 - list of trial sites and climatic details

All trial sites and according climatic details are given. Climate variables were provided by the Central Institute for Meteorology and Geodynamics, Vienna, Austria. For details see DOI: 10.1016/j.foreco.2012.01.03