engleski

Mesoscale patterns of long-term precipitation variability in the “ Greater Alpine Region”

In the final phase of EU-project ALPCLIM (1999-2002) and as a pre-condition for EU-project ALP-IMP (2003-2006) and Austrian national funded project CLIVALP (2002-2005) a new instrumental precipitation dataset was created. It covers the Alps and its wider surroundings (4 to 19 deg E, 43 to 49 deg N), has a high spatial resolution (apprx. 180 single site series of monthly precipitation sums), covers the entire instrumental period (the longest series starting in the year 1800), meets high quality standards due to an extensive quality and homogeneity testing, correcting and adjusting procedure and has been interpolated to a regular grid of 1 deg long-lat. It supplements the already available and published similar temperature dataset for the region and it will be followed by similar datasets for other climate elements (work in progress already for air-pressure and sunshine/cloudiness, other elements to be started). Unlike temperature, whose long-term variability in time turned out to be rather homogeneous in space, precipitation variability shows interesting spatial variability features. One dominant feature seems to be a dipole-like long-term structure from a mode of high precipitation S and SE of the Alps and low precipitation NW and N of the Alps in the 19th century which has changed now to the inverse mode (wet NW-N versus dry S-SE) which dominates the recent decades. Another topic of the presentation will be the spatial structure and the variability of the seasonal precipitation patterns. The study region shows steep spatial gradients between different seasonal types (dominating summer precipitation, spring and/or autumn maximum, flat annual course… ) which are not stable in time. Last but not least the quality test procedure (based on GIS-sustained single month spatial comparisons) allows the data-set also to be used for extreme event studies (both for months with excessive precipitation as well as dry months). First such long-term trends of extreme precipitation will be shown.

precipitation; Greater Alpine Region; long-term variability

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