Vassilis Z. Antonopoulos, Zissis V. Antonopoulos, George P. Tsakiris
Abstract Meteorological and climate reports indicate that the last ten years rank among the warmest on record. In recent decades, the impacts of climate change on lake water quality and energy budget have become a major concern for scientists and local communities. In this study, trend analyses of monthly and annual historical time series of thermal and water quality parameters were conducted for two Mediterranean Lakes, Vegoritis and Volvi in Greece. These parameters were analysed using a process-based lake water quality model QUALAKE, calibrated for the period 2009–2024. Trend analysis for multiple lake variables indicated limited impacts on most parameters with both Mann-Kendall and Spearman’s rho tests. Trends were detected in several parameters at both annual and monthly time scales, although discrepancies were observed for some variables. Water temperature and dissolved oxygen concentrations in the epilimnion exhibited consistent temporal changes, identified by both statistical tests. Among the heat budget components, the incoming shortwave radiation (R s ) and the net radiation (R n ) showed weak trends, while soluble reactive phosphorus (SRP) displayed weak downward trend in both epilimnetic and depth-averaged concentrations. No significant trends were detected in air temperature, rainfall, evaporation or several other examined parameters.