@article{ArguellodeSouzaSamprognaMohorGuzmanAriasetal.2023, author = {Arguello de Souza, Felipe Augusto and Samprogna Mohor, Guilherme and Guzman Arias, Diego Alejandro and Sarmento Buarque, Ana Carolina and Taffarello, Denise and Mendiondo, Eduardo Mario}, title = {Droughts in S{\~a}o Paulo}, series = {Urban water journal}, volume = {20}, journal = {Urban water journal}, number = {10}, publisher = {Taylor \& Francis}, address = {London [u.a.]}, issn = {1573-062X}, doi = {10.1080/1573062X.2022.2047735}, pages = {1682 -- 1694}, year = {2023}, abstract = {Literature has suggested that droughts and societies are mutually shaped and, therefore, both require a better understanding of their coevolution on risk reduction and water adaptation. Although the Sao Paulo Metropolitan Region drew attention because of the 2013-2015 drought, this was not the first event. This paper revisits this event and the 1985-1986 drought to compare the evolution of drought risk management aspects. Documents and hydrological records are analyzed to evaluate the hazard intensity, preparedness, exposure, vulnerability, responses, and mitigation aspects of both events. Although the hazard intensity and exposure of the latter event were larger than the former one, the policy implementation delay and the dependency of service areas in a single reservoir exposed the region to higher vulnerability. In addition to the structural and non-structural tools implemented just after the events, this work raises the possibility of rainwater reuse for reducing the stress in reservoirs.}, language = {en} } @article{CiemerRehmKurthsetal.2020, author = {Ciemer, Catrin and Rehm, Lars and Kurths, J{\"u}rgen and Donner, Reik Volker and Winkelmann, Ricarda and Boers, Niklas}, title = {An early-warning indicator for Amazon droughts exclusively based on tropical Atlantic sea surface temperatures}, series = {Environmental Research Letters}, volume = {15}, journal = {Environmental Research Letters}, number = {9}, publisher = {IOP - Institute of Physics Publishing}, address = {Bristol}, pages = {10}, year = {2020}, abstract = {Droughts in tropical South America have an imminent and severe impact on the Amazon rainforest and affect the livelihoods of millions of people. Extremely dry conditions in Amazonia have been previously linked to sea surface temperature (SST) anomalies in the adjacent tropical oceans. Although the sources and impacts of such droughts have been widely studied, establishing reliable multi-year lead statistical forecasts of their occurrence is still an ongoing challenge. Here, we further investigate the relationship between SST and rainfall anomalies using a complex network approach. We identify four ocean regions which exhibit the strongest overall SST correlations with central Amazon rainfall, including two particularly prominent regions in the northern and southern tropical Atlantic. Based on the time-dependent correlation between SST anomalies in these two regions alone, we establish a new early-warning method for droughts in the central Amazon basin and demonstrate its robustness in hindcasting past major drought events with lead-times up to 18 months.}, language = {en} } @article{GuzmanAriasSamprognaMohorMendiondo2022, author = {Guzman Arias, Diego Alejandro and Samprogna Mohor, Guilherme and Mendiondo, Eduardo Mario}, title = {Multi-driver ensemble to evaluate the water utility business interruption cost induced by hydrological drought risk scenarios in Brazil}, series = {Urban water journal}, journal = {Urban water journal}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {1573-062X}, doi = {10.1080/1573062X.2022.2058564}, pages = {15}, year = {2022}, abstract = {Climate change and increasing water demand in urban environments necessitate planning water utility companies' finances. Traditionally, methods to estimate the direct water utility business interruption costs (WUBIC) caused by droughts have not been clearly established. We propose a multi-driver assessment method. We project the water yield using a hydrological model driven by regional climate models under radiative forcing scenarios. We project water demand under stationary and non-stationary conditions to estimate drought severity and duration, which are linked with pricing policies recently adopted by the Sao Paulo Water Utility Company. The results showed water insecurity. The non-stationary trend imposed larger differences in the drought resilience financial gap, suggesting that the uncertainties of WUBIC derived from demand and climate models are greater than those associated with radiative forcing scenarios. As populations increase, proactively controlling demand is recommended to avoid or minimize reactive policy changes during future drought events, repeating recent financial impacts.}, language = {en} } @article{ZaplataNhabangaStalmansetal.2020, author = {Zaplata, Markus Klemens and Nhabanga, Abel and Stalmans, Marc and Volpers, Thomas and Burkart, Michael and Sperfeld, Erik}, title = {Grasses cope with high-contrast ecosystem conditions in the large outflow of the Banhine wetlands, Mozambique}, series = {African journal of ecology}, volume = {59}, journal = {African journal of ecology}, number = {1}, publisher = {Wiley}, address = {Hoboken}, issn = {0141-6707}, doi = {10.1111/aje.12820}, pages = {190 -- 203}, year = {2020}, abstract = {Ecosystems with highly pulsed water supply must be better understood as climate change may increase frequency and severity of intense storms, droughts and floods. Here we collected data over 3 years (2016-2018) in the episodic wetland outflow channel (Aluize), Banhine National Park, in which the system state changed from dry to wet to dry. Field sampling included vegetation records, small-scale vegetation zoning, the seed bank and water and soil quality. The same main plant species were found in both dry and wet conditions across the riverbed of the outflow channel. We found only very few diaspores of plants in the soil after prolonged drought. In the subsequent flooded state, we examined very dense vegetation on the water surface, which was dominated by the gramineous species Paspalidium obtusifolium. This species formed a compact floating mat that was rooted to the riverbed. The Cyperaceae Bolboschoenus glaucus showed high clonal growth in the form of root tubers, which likely serve as important food reservoir during drought. Soil and water analyses do not indicate a limitation by nutrients. We outline how resident people may change the plant community structure with an increasing practice of setting fire to the meadows in the dried-up riverbed to facilitate plant regrowth as food for their livestock.}, language = {en} }