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Regional climate models (RCM) provide site-specific meteorological data at a suitable spatial resolution for the estimation of future climate-driven changes in aquatic ecosystems. In this study, we used meteorological data from the RCM weather-situation-based regionalization method (WETTREG), available for Germany, to force a one-dimensional hydrodynamic lake model to simulate climate-induced changes on the summer thermal stratification of Lake Ammersee in southern Germany. In comparison to the period of 2002–2010, an extension by 22 days of the summer stratification period was simulated for 2042–2050. Further, a vertical shift in the position of metalimnion and thermocline within the lake was not detected, but a slight increase in the metalimnion thickness during mid-summer of 1 m was simulated. Along with these changes in stratification patterns, warming for the epilimnion water temperatures during summer stratification and for the entire water body in winter were simulated for the future. By contrast the hypolimnion temperatures are simulated to decrease during the summer stratification. In addition to simulating future limno-physical aspects, the investigation demonstrates that the RCM data of the WETTREG projection are suitable for conducting climate change impact studies.
Unlike other aquatic continental ecosystems such as lakes, small coastal brooks have not been used as indicators of anthropogenic or climatic impacts. Our study addresses reconstructing the evolution of coastal brooks in the southwest of Spain from the early 17th century to the end of the 20th century using fieldwork, remote sensing, historical sources and microrelief. These brooks have had a continuous regression, losing 84.7% of their length since 1630 AD. From the 17th century to the beginning of the 20th century, climatic factors were responsible for the filling and siltation of the thalweg of brooks with sandy sediments of eolian origin. The alternation of dry and humid periods during the Little Ice Age in southern Spain favoured the mobilisation of sandy sediments in a process of secondary dunification, which was initiated during the 18th century and prominent at the end of the Little Ice Age. This process has coincided with a loss of water availability or an increase of aridity in some lakes and lagoons of southwestern Europe at the end of the 19th century. However, during the second half of the 20th century, the average annual rate of thalweg regression almost quadrupled to 432.2 m∙year-1 mainly due to anthropogenic impacts associated with logging. These changes coincide with the mobilisation of sandy sediment and the erosion of coastal brooks in southwestern Portugal and other continental aquatic ecosystems in southwestern Spain. Therefore, we believe that changes in small coastal brooks can be used as indicators of anthropogenic and climatic impacts and, in the future, as sentinels to study the effects of climatic change just as lakes, reservoirs and rivers are considered.
Simulating water temperatures and stratification of a pre-alpine lake with a hydrodynamic model
(2013)
We report on the calibration of the one-dimensional hydrodynamic lake model Dynamic Reservoir Simulation Model to simulate the water temperature conditions of the pre-alpine Lake Ammersee (southeast Germany) that is a representative of deep and large lakes in this region. Special focus is given to the calibration in order to reproduce the correct thermal distribution and stratification including the time of onset and duration of summer stratification. To ensure the application of the model to investigate the impact of climate change on lakes, an analysis of the model sensitivity under stepwise modification of meteorological input parameters (air temperature, wind speed, precipitation, global radiation, cloud cover, vapour pressure and tributary water temperature) was conducted. The total mean error of the calibration results is −0.23 °C, the root mean square error amounts to 1.012 °C. All characteristics of the annual stratification cycle were reproduced accurately by the model. Additionally, the simulated deviations for all applied modifications of the input parameters for the sensitivity analysis can be differentiated in the high temporal resolution of monthly values for each specific depth. The smallest applied alteration to each modified input parameter caused a maximum deviation in the simulation results of at least 0.26 °C. The most sensitive reactions of the model can be observed through modifications of the input parameters air temperature and wind speed. Hence, the results show that further investigations at Lake Ammersee, such as coupling the hydrodynamic model with chemo-dynamic models to assess the impact of changing climate on biochemical conditions within lakes, can be carried out using Dynamic Reservoir Simulation Model.
Thermal dynamics of lakes has a key role in chemical and biological processes in lakes including nutrient distributions and phytoplankton growth. Applications of hydrodynamic models to lakes can provide insights into possible future alterations in thermal dynamics induced by climate change. In this study we present the calibration and validation of the newest version of the open-source hydrodynamic model GLM (General Lake Model) to the dimictic Lake Ammersee, located in south-east Germany. The simulation of lake water temperatures for the calibration period revealed an overall root mean square error of 0.65 °C and a mean error of 0.08 °C. The seasonal stratification pattern and the annual thermal structure of this dimictic lake were reproduced by the model. The model simulated the presence of winter ice cover for the only year out of eight years simulated, when ice cover was observed. Elevated lake water temperatures were also reproduced in model simulations during a period in 2003 of unusually high air temperatures. Statistical analysis of the model calibration results for Lake Ammersee indicates a fit comparable to, or better than most other well-established hydrodynamic models and provides an opportunity for continuous simulations through periods of ice cover. Our results indicate a major improvement of GLM compared with earlier model versions and demonstrate the applicability of GLM for limnophysical studies, particularly for altered forcing conditions such as climate change.
Modellierungsansatz und Szenarien zur limnologischen Entwicklung des Ammersees im Klimawandel
(2012)
Der Klimawandel in Nürnberg unter Berücksichtigung unterschiedlicher Klimamodelle und –szenarien
(2012)
Der Ammersee im Klimawandel
(2014)
The Importance of Wetlands and Unhealthy Water Bodies in the Distribution of Malaria in Spain
(2019)
Malaria is one of the most cited vector-borne infectious diseases by climate change expert panels. Malaria vectors often need water sheets or wetlands to complete the disease life cycle. The current context of population mobility and global change requires detailed monitoring and surveillance of malaria in all countries. This study analysed the spatiotemporal distribution of death and illness cases caused by autochthonous and imported malaria in Spain during the 20th and 21st centuries using multidisciplinary sources, Geographic Information System (GIS) and geovisualisation. The results obtained reveal that, in the 20th and 21st centuries, malaria has not had a homogeneous spatial distribution. Between 1916 and 1930, 77% of deaths from autochthonous malaria were concentrated in only 20% of Spanish provinces; in 1932, 88% of patients treated in anti-malarial dispensaries were concentrated in these same provinces. These last data reveal the huge potential that anti-malarial dispensaries could have as a tool to reconstruct historical epidemiology. Spanish autochthonous malaria has presented epidemic upsurge episodes, especially those of 1917–1922 and 1939–1944, influenced by armed conflict, population movement and damaged health and hygiene conditions. Although meteorological variables have not played a key role in these epidemic episodes, they contributed by providing suitable conditions for their intensification. After the eradication of autochthonous malaria in 1961, imported malaria cases began to be detected in 1973, reaching more than 700 cases per year at the end of the second decade of the 21st century. Therefore, consistent and detailed historical studies are necessary to better understand the drivers that have led to the decline and elimination of malaria in Europe and other temperate countries.
Geovisualizations that use a virtual reality headset can have a more immersive effect on users than when only a desktop application is viewed. However, to have an overview, a VR 3D map is usually viewed from a top-down perspective. On the other hand, the first-person perspective is used when the scenario is visualized as realistically as possible, and the ultimate goal is to feel present inside the 3D city. With the help of dynamic cartographic visualization methods, such as animated symbols appearing or a dynamic change of selected or complete visualization, it is possible to convey targeted information while being inside the 3D. For this purpose, techniques and ideas from cartography and video games were utilized and combined. The combination resulted in dynamically changeable symbol objects, which can be placed automatically using tables or building information, and dynamically changeable post-processing methods. Users can interactively select a predefined set of visualization methods and show/hide dynamic cartographic symbols in the running application via an interface. The study aims to develop cartographic visualization methods that can be technically used within a game engine for VR applications to improve spatial perception.