Recent projections estimate that lakes, responding rapidly to climate change, will get warmer for longer periods, with heatwaves potentially spreading across multiple seasons. In some regions, heatwaves can add to existing pressure from drought which can lower lake levels and areal extent resulting from reduced inflows, increased evaporation and extraction for anthropogenic purposes. In lakes, intense phytoplankton blooms might be the result of consecutive heatwave. Increasing risk of wildfire, when high temperature are combined with low rainfall and dry vegetation, can have a significant hydro-geomorphological impact on watersheds. Post-fire rainfall events can trigger erosion and transport processes leading to potential alteration of water quality. While this topic has mainly been addressed at small scales there remains a poor understanding at larger scales. The Lakes_CCI project develops consistent long-term datasets covering Lake Water Level, Extent, Surface, Temperature, Ice cover and leaving Reflectance. A first datasets including about 2000 lakes for the period 1992-2020 has been released https://catalogue.ceda.ac.uk/uuid/a07deacaffb8453e93d57ee214676304). One scope of the project is the integration of different satellite-derived products across ESA CCI projects. A study is aiming to investigate the relationship between fires and lakes water quality over a wide range of geographical regions and fire regimes. The Fire_CCI project, focuses on several issues related to fire disturbance including analysing and specifying scientific requirements linked to climate and production of burned area datasets. In this study potential of the CCI dataset is explored in two different case studies in the Eurasian region. Chl-a data were examined for any potential responses during the 2019 double heatwave period for 36 European lakes. It has shown that the timing and magnitude of the response to the heatwave events depends on lake depth and nutrients. Time series and relationships among fires (i.e., burned area), meteo-climatic parameters and water quality variables (chlorophyll-a, turbidity) for the period 2003-2020 were analysed for three sub-basins of the Lake Baikal. Time series analysis showed seasonal (April-June) and interannual fire occurrence, precipitation patterns (high intensity in summer) and no significant temporal changes for water quality variables during the studied periods. The three lake sub-basins investigated have shown to respond differently according to their morphology, land cover types and meteoclimatic conditions, indicating their importance in determining the response of water variables to the impact of fires. Overall, our finding suggests that Lake Baikal shows resilience in the medium-long term to potential effects of fires and climate change in the region.
Impact on lake surface water quality of heatwaves and burning events in the lakes watershed
Monica Pinardi;Mariano Bresciani;Daniela Stroppiana;Rossana Caroni;Lorenzo Parigi;Giulio Tellina;Claudia Giardino;
2023
Abstract
Recent projections estimate that lakes, responding rapidly to climate change, will get warmer for longer periods, with heatwaves potentially spreading across multiple seasons. In some regions, heatwaves can add to existing pressure from drought which can lower lake levels and areal extent resulting from reduced inflows, increased evaporation and extraction for anthropogenic purposes. In lakes, intense phytoplankton blooms might be the result of consecutive heatwave. Increasing risk of wildfire, when high temperature are combined with low rainfall and dry vegetation, can have a significant hydro-geomorphological impact on watersheds. Post-fire rainfall events can trigger erosion and transport processes leading to potential alteration of water quality. While this topic has mainly been addressed at small scales there remains a poor understanding at larger scales. The Lakes_CCI project develops consistent long-term datasets covering Lake Water Level, Extent, Surface, Temperature, Ice cover and leaving Reflectance. A first datasets including about 2000 lakes for the period 1992-2020 has been released https://catalogue.ceda.ac.uk/uuid/a07deacaffb8453e93d57ee214676304). One scope of the project is the integration of different satellite-derived products across ESA CCI projects. A study is aiming to investigate the relationship between fires and lakes water quality over a wide range of geographical regions and fire regimes. The Fire_CCI project, focuses on several issues related to fire disturbance including analysing and specifying scientific requirements linked to climate and production of burned area datasets. In this study potential of the CCI dataset is explored in two different case studies in the Eurasian region. Chl-a data were examined for any potential responses during the 2019 double heatwave period for 36 European lakes. It has shown that the timing and magnitude of the response to the heatwave events depends on lake depth and nutrients. Time series and relationships among fires (i.e., burned area), meteo-climatic parameters and water quality variables (chlorophyll-a, turbidity) for the period 2003-2020 were analysed for three sub-basins of the Lake Baikal. Time series analysis showed seasonal (April-June) and interannual fire occurrence, precipitation patterns (high intensity in summer) and no significant temporal changes for water quality variables during the studied periods. The three lake sub-basins investigated have shown to respond differently according to their morphology, land cover types and meteoclimatic conditions, indicating their importance in determining the response of water variables to the impact of fires. Overall, our finding suggests that Lake Baikal shows resilience in the medium-long term to potential effects of fires and climate change in the region.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
