A signature-based approach to quantify soil moisture dynamics under contrasting land-uses

Soil moisture signatures provide a promising solution to overcome the difficulty of evaluating soil moisture dynamics in hydrologic models. Soil moisture signatures are metrics that quantify the dynamic aspects of soil moisture timeseries and enable process-based model evaluations. To date, soil moisture signatures have been tested only under limited land-use types. In this study, we explore soil moisture signatures’ ability to discriminate different dynamics among contrasting land-uses. We applied a set of nine soil moisture signatures to datasets from six in-situ soil moisture networks worldwide. The dataset covered a range of land-use types, including forested and deforested areas, shallow groundwater areas, wetlands, urban areas, grazed areas, and cropland areas. Our set of signatures characterized soil moisture dynamics at three temporal scales: event, season, and a complete timeseries. Statistical assessment of extracted signatures showed that (1) event-based signatures can distinguish different dynamics for all the land-uses, (2) season-based signatures can distinguish different dynamics for some types of land-uses (deforested vs. forested, urban vs. greenspace, and cropped vs. grazed vs. grassland contrasts), (3) timeseries-based signatures can distinguish different dynamics for some types of land-uses (deforested vs. forested, urban vs. greenspace, shallow vs. deep groundwater, wetland vs. non-wetland, and cropped vs. grazed vs. grassland contrasts). Further, we compared signature-based process interpretations against literature knowledge; event-based and timeseries-based signatures generally matched well with previous process understandings from literature, but season-based signatures did not. This study will be a useful guideline for understanding how catchment-scale soil moisture dynamics in various land-uses can be described using a standardized set of hydrologically relevant metrics.

Climate changes in recent decades, the evolution of the drought phenomenon and their influence on vineyards in north-eastern Romania

Unfavourable trends have been identified in the evolution of climate factors (temperatures, precipitation, etc.) over the past years, with a direct impact on the vegetative and productive potential of the vine. This calls for a reassessment of climate resources and the adaptation of cultivation technologies to the new conditions. Our paper analyses the climate data recorded between 1991 and 2020 for the Iaşi vineyard ecosystem, which allowed for the calculation of a series of bioclimatic indices and coefficients, deviations from the multiannual average values, soil moisture dynamics, and their influence on development of vegetation phenophases and grape production. The increasing tendency of the average annual temperature and the decreasing amounts of precipitation registered point to a marked warming of the vineyard climate, especially after 2000. The high values of temperatures, corroborated with the soil water deficit, determined an intensification of the atmospheric and pedological drought, a shift in vegetation phenophases, shortened development periods and a forced ripening of grapes, with a negative impact on yields, which fluctuated from one year to another. The analysis of the ecoclimate conditions over the past 30 years has highlighted an alternation of periods, a colder and wetter one between 1991 and 2006, and a warmer and dried one between 2007 and 2020.