Spatial and temporal variability of surface dust concentration in western Crete (Greece) – Development of a monitoring network

Abstract

The influence of long-range dust on soils and different ecological processes in deposition regions in the eastern Mediterranean depends primarily on the deposited amounts and therefore on transport dynamics, while its geochemical and mineralogical composition also plays an important role. As local distributions cannot be fully represented and analyzed by satellite data due to its relatively coarse spatial and temporal resolution, ground truth data is required. For this purpose, a network of eight sampling/monitoring stations was installed around the Lefka Ori mountains in western Crete (Greece), each equipped with a deposition sampler and an optical-particle-counter in order to detect the spatial variability in dust concentration and deposition. Measured dust concentrations for the period from March 2023 to April 2024 show significant differences between the individual site locations. By comparison with meteorological data, correlations with wind directions can be identified. Thereby, wind directions during dust events generally differ significantly between stations. Furthermore, we are able to differentiate between a fine-grained (< 1 μm in diameter) background dust load and event-based coarser-grained (1–10 μm) dust loads as well as between synoptically and regionally induced dust events. First results of mineralogical analysis clearly identify the deposited fine material to be of north African origin, indicated by the presence of kaolinite, sepiolite and palygorskite. In combination with high-resolution meteorological data, the measurement design allows for the differentiation between the influences of synoptic and local to regional conditions and therefore contributes to a detailed understanding of dust distribution in western Crete.