CorsiClimAte - Saisonale und topographische Dekomposition von Wasserdampftransport, Wolken und Niederschlag in Korsika unter besonderer Berücksichtigung der PBL Höhe
Zusammenfassung der Projektergebnisse
The main aim of the project CorsiClimAte was to investigate the precipitation dynamics of Corsica in order to unveil the interplay between local breeze systems, large-scale circulation pattern and topography. Local-scale characteristics and the interplay were analyzed with special reference to turbulence production (as indicated by turbulence kinetic energy TKE) and the planetary boundary layer (PBL). The work was conducted by establishing an altitudinal transect of automatic weather stations (AWS) from west to east, by analyzing longer-term climate and re-analysis data, by conducting WRF simulations analyzing cross-scale dynamics of moisture transport inducing precipitation, by exploiting high resolution spatial explicit data on fog-low stratus (FLS) occurrence derived from remote-sensing, and by HYPSLIT back trajectory modelling. The analysis of re-analysis and rain data revealed six dominating rain weather types for Corsica, where intense rainfall was more related to a meridional streamflow over the Mediterranean and short intense rainfall could be related to mesoscale breeze systems during anticyclonic conditions. The different rain intensities could be related to the dynamics of the planetary boundary layer height (PBLH), with clear difference between the coast (more shallow PBLHs) and inland areas (higher PBLHs due to advective processes). Turbulence kinetic energy (TKE) as an important player in cloud and rain formation turned out to be more thermally driven during summer and autumn, while larger scale advection played a greater role for high TKE values during rainfall in winter and spring. Back trajectory analyses revealed that air mass and moisture supply for Corsican rain days in winter are more originating from the northern and western sector (Atlantic, NW Europe) while short trajectories from the Mediterranean in summer and autumn pointed to a predominance of regional water sources for precipitation formation, particularly for rain days occurring during larger-scale anticyclonic weather types. Altogether, the western and eastern parts of the island differ, with a higher impact of larger-scale advection on rain formation at the western slopes compared to the eastern shorelines. Synthesizing our data and results with the other subprojects revealed a varying use of water sources (rain, snow, deep soil) for tree growth depending on the location (shoreline, slopes etc.). Also, the season played a major role, where we found that tree growth at coastal areas profit most from late spring rainfall, while the higher sites are particularly dependent on autumn precipitation. It could be shown that especially tree growth at the higher sites were less vulnerable against droughts, so that particularly the higher inland areas will be more affected by the expected rainfall reduction in the Mediterranean under climate change.
Projektbezogene Publikationen (Auswahl)
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(2020): First indications of seasonal and spatial variations of water sources in pine trees along an elevation gradient in a Mediterranean ecosystem derived from δ18O. Chemical Geology 549, 119695
Szymczak, S., Barth, J., Bendix, J., Huneau, F., Garel, E., Häusser, M., Juhlke, T., Knerr, I., Santoni, S., Mayr, C., Trachte, K., van Geldern, R. & Bräuning, A.
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(2020): How Do Mediterranean Pine Trees Respond to Drought and Precipitation Events along an Elevation Gradient? Forests 11(7), 1
Szymczak, S., Häusser, M., Garel, E., Santoni, S., Huneau, F., Knerr, I., Trachte, K., Bendix, J. & Bräuning, A.
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(2020): Partitioning of Large-Scale and Local-Scale Precipitation Events by Means of Spatio-Temporal Precipitation Regimes on Corsica. Atmosphere 11(4), 417
Knerr, I., Trachte, K., Garel, E., Huneau, F., Santoni, S. & Bendix, J.
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(2020): Tritium as a hydrological tracer in Mediterranean precipitation events. Atmospheric Chemistry and Physics 20, 3555-3568
Juhlke, T. R., Sültenfuß, J., Trachte, K., Huneau, F., Garel, E., Santoni, S. Barth, J. A. C. & van Geldern, R.
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(2021): Fog - low stratus (FLS) regimes on Corsica with wind and PBLH as key drivers. Atmospheric Research 261, 105731
Knerr, I., Trachte, K., Egli, S., Barth, J., Bräuning, A., Garel, E., Häusser, M., Huneau, F., Juhlke, T., Santoni, S., Szymczak, S., van Geldern, R. & Bendix, J.
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(2021): Temporal offset between precipitation and water uptake of Mediterranean pine trees varies with elevation and season. Science of The Total Environment 755, 142539
Juhlke, T., Geldern, R.V., Barth, J., Bendix, J., Bräuning, A., Garel, E., Häusser, M., Huneau, F., Knerr, I., Santoni, S., Szymczak, S. & Trachte, K.
