Modeling and Upscaling Plot-Scale Soil Erosion under Mediterranean Climate Variability

Abstract

Abstract:Soil erosion is an issue in the Mediterranean slopes. Erosion plots are useful to quantify erosion rates, but data are difficult to scale up to a slope level. Moreover, short observational frameworks are generally established, making it difficult to represent multi-year fluctuations. This paper deals with the potential of parsimonious modelling to upscale plot erosion (~23 m 2 ) at Monte Pino Met European Research Observatory (South Italy) from 2001 to 2006. Under the assumption that the slope is fractal and contains plots, monthly gross soil erosion was modeled by lumping together the erosivity factor (runoff component), Normalized Difference Vegetation Index (vegetation cover factor), and the spatial scale dependence (slope length factor). This model was applied to reconstruct monthly gross soil erosion rates for the period of 1986-2006, for which hydrological inputs were available with sufficient detail. Pronounced interannual variations, with two distinct patterns, were observed: increasing rates of erosion were visible in 1995-2006 (peaking in November 1997, 50 Mg·ha −1 ·month −1 ), while in previous years only a few peaks slightly exceeded the average of the whole period (1 Mg·ha −1 ·month −1 ). Hydrological conditions indicate that important erosional processes have been triggered during low-frequency, short rainfall events occurring in spring-summer (e.g., May 2001, June 2003, or during longer, less intense events occurring in autumn-winter (e.g., November 1997) seasons. It is likely that increased precipitation amounts associated with more frequent convective storms created conditions for higher energy events triggering erosion. For the recent warm period, investigations at a higher than monthly resolution are required to better assess the seasonal changes of erosion rates and their relationship with soil conservation.

Climate Patterns in the World’s Longest History of Storm-Erosivity: The Arno River Basin, Italy, 1000–2019 CE

“…where one scale factor s 1.35 and three relative weighting factors a 1 0.2, a 2 0.1 and a 3 0.7 are calibrated values to converge to the long-term areal mean (1541 MJ mm hm −2 h −1 yr −1 ; Figure 1B). The estimated scale factor 1 < s < 2 is an upscaling parameter, which is consistent with the assumption that individual sites are fractal elements of the area (e.g., Diodato et al, 2017b). The estimated relative weighting factors a i (i 1, 2, 3) reflect the characteristics of the three stations (e.g., Bartolini et al, 2018).…”

Prediction of Reservoir Sediment Quality Based on Erosion Processes in Watershed Using Mathematical Modelling

“…Conventional methods to assess soil erosion [27] and sediment-associated chemical runoff are expensive, time-consuming, and need to be collected over many years [28,29]. Nowadays, preference is given to predict [30] and control sediment and nutrient yields from agricultural nonpoint source runoff using mathematical models [31]. Soil erosion models can assess and simulate the extent and magnitude of erosion processes in watershed.…”