@article{CodecoWeisAndersen2022, author = {Code{\c{c}}o, Marta S. and Weis, Philipp and Andersen, Christine}, title = {Numerical modeling of structurally controlled ore formation in magmatic-hydrothermal systems}, series = {Geochemistry, geophysics, geosystems : G 3 ; an electronic journal of the earth sciences}, volume = {23}, journal = {Geochemistry, geophysics, geosystems : G 3 ; an electronic journal of the earth sciences}, number = {8}, publisher = {American Geophysical Union}, address = {Washington, DC}, issn = {1525-2027}, doi = {10.1029/2021GC010302}, pages = {20}, year = {2022}, abstract = {Faults and fractures can be permeable pathways for focused fluid flow in structurally controlled ore-forming hydrothermal systems. However, quantifying their role in fluid flow on the scale of several kilometers with numerical models typically requires high-resolution meshes. This study introduces a modified numerical representation of m-scale fault zones using lower-dimensional elements (here, one-dimensional [1D] elements in a 2D domain) to resolve structurally controlled fluid flow with coarser mesh resolutions and apply the method to magmatic-hydrothermal ore-forming systems. We modeled horizontal and vertical structure-controlled magmatic-hydrothermal deposits to understand the role of permeability and structure connectivity on ore deposition. The simulation results of vertically extended porphyry copper systems show that ore deposition can occur along permeable vertical structures where ascending, overpressured magmatic fluids are cooled by downflowing ambient fluids. Structure permeability and fault location control the distribution of ore grades. In highly permeable structures, the mineralization can span up to 3 km vertically, resulting in heat-pipe mechanisms that promote the ascent of a magmatic vapor phase to an overlying structurally controlled epithermal system. Simulations for the formation of subhorizontal vein-type deposits suggest that the major control on fluid flow and metal deposition along horizontal structures is the absence of vertical structures above the injection location but their presence at greater distances. Using a dynamic permeability model mimicking crack-seal mechanisms within the structures leads to a pulsating behavior of fracture-controlled hydrothermal systems and prevents the inflow of ambient fluids under overpressured conditions.}, language = {en} } @article{ApelVorogushynMerz2022, author = {Apel, Heiko and Vorogushyn, Sergiy and Merz, Bruno}, title = {Brief communication: impact forecasting could substantially improve the emergency management of deadly floods: case study July 2021 floods in Germany}, series = {Natural hazards and earth system sciences}, volume = {22}, journal = {Natural hazards and earth system sciences}, number = {9}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, issn = {1561-8633}, doi = {10.5194/nhess-22-3005-2022}, pages = {3005 -- 3014}, year = {2022}, abstract = {Floods affect more people than any other natural hazard; thus flood warning and disaster management are of utmost importance. However, the operational hydrological forecasts do not provide information about affected areas and impact but only discharge and water levels at gauges. We show that a simple hydrodynamic model operating with readily available data is able to provide highly localized information on the expected flood extent and impacts, with simulation times enabling operational flood warning. We demonstrate that such an impact forecast would have indicated the deadly potential of the 2021 flood in western Germany with sufficient lead time.}, language = {en} } @article{BillingThonickeSakschewskietal.2022, author = {Billing, Maik and Thonicke, Kirsten and Sakschewski, Boris and von Bloh, Werner and Walz, Ariane}, title = {Future tree survival in European forests depends on understorey tree diversity}, series = {Scientific reports}, volume = {12}, journal = {Scientific reports}, number = {1}, publisher = {Springer Nature}, address = {Berlin}, issn = {2045-2322}, doi = {10.1038/s41598-022-25319-7}, pages = {12}, year = {2022}, abstract = {Climate change heavily threatens forest ecosystems worldwide and there is urgent need to understand what controls tree survival and forests stability. There is evidence that biodiversity can enhance ecosystem stability (Loreau and de Mazancourt in Ecol Lett 16:106-115, 2013; McCann in Nature 405:228-233, 2000), however it remains largely unclear whether this also holds for climate change and what aspects of biodiversity might be most important. Here we apply machine learning to outputs of a flexible-trait Dynamic Global Vegetation Model to unravel the effects of enhanced functional tree trait diversity and its sub-components on climate-change resistance of temperate forests (http://www.pik-potsdam.de/similar to billing/video/Forest_Resistance_LPJmLFIT.mp4). We find that functional tree trait diversity enhances forest resistance. We explain this with 1. stronger complementarity effects (similar to 25\% importance) especially improving the survival of trees in the understorey of up to +16.8\% (+/- 1.6\%) and 2. environmental and competitive filtering of trees better adapted to future climate (40-87\% importance). We conclude that forests containing functionally diverse trees better resist and adapt to future conditions. In this context, we especially highlight the role of functionally diverse understorey trees as they provide the fundament for better survival of young trees and filtering of resistant tree individuals in the future.}, language = {en} } @article{LunaKorup2022, author = {Luna, Lisa and Korup, Oliver}, title = {Seasonal landslide activity lags annual precipitation pattern in the Pacific Northwest}, series = {Geophysical research letters}, volume = {49}, journal = {Geophysical research letters}, number = {18}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {0094-8276}, doi = {10.1029/2022GL098506}, pages = {11}, year = {2022}, abstract = {Seasonal variations in landslide activity remain understudied compared to recent advances in landslide early warning at hourly to daily timescales. Here, we learn the seasonal pattern of monthly landslide activity in the Pacific Northwest from five heterogeneous landslide inventories with differing spatial and temporal coverage and reporting protocols combined in a Bayesian multi-level model. We find that landslide activity is distinctly seasonal, with credible increases in landslide intensity, inter-annual variability, and probability marking the onset of the landslide season in November. Peaks in landslide probability in January and intensity in February lag the annual peak in mean monthly precipitation and landslide activity is more variable in winter than in summer, when landslides are rare. For a given monthly rainfall, landslide intensity at the season peak in February is up to 10 times higher than at the onset in November, underlining the importance of antecedent seasonal hillslope conditions.}, language = {en} } @article{SteinMukkavilliWagener2022, author = {Stein, Lina and Mukkavilli, Surya Karthik and Wagener, Thorsten}, title = {Lifelines for a drowning science - improving findability and synthesis of hydrologic publications}, series = {Hydrological processes}, volume = {36}, journal = {Hydrological processes}, number = {11}, publisher = {Wiley}, address = {New York, NY}, issn = {0885-6087}, doi = {10.1002/hyp.14742}, pages = {7}, year = {2022}, abstract = {Increasing publication numbers make it difficult to keep up with knowledge evolution in a science like hydrology. Here we give recommendations to authors and journals for writing future-proof articles that contribute to knowledge accumulation and synthesis.}, language = {en} } @article{HeydenNatho2022, author = {Heyden, Janika and Natho, Stephanie}, title = {Assessing floodplain management in Germany - a case study on nationwide research and actions}, series = {Sustainability}, volume = {14}, journal = {Sustainability}, number = {17}, publisher = {MDPI}, address = {Basel}, issn = {2071-1050}, doi = {10.3390/su141710610}, pages = {18}, year = {2022}, abstract = {After a long history of floodplain degradation and substantial losses of inundation areas over the last decades, a rethinking of floodplain management has taken place in Germany. Floodplains are now acknowledged as important areas for both biodiversity and society. This transformation has been significantly supported by nationwide research activities. A systematic assessment of the current floodplain management is still lacking. We therefore developed a scheme to assess floodplain management through the steps of identification, analysis, implementation, and evaluation. Reviewing the data and literature on nationwide floodplain-related research and activities, we defined key elements of floodplain management for Germany. We concluded that research activities already follow a strategic nationwide approach of identifying and analyzing floodplains. Progress in implementation is slow, however, and potentials are far from being reached. Nevertheless, new and unique initiatives enable Germany to stay on the long-term path of giving rivers more space and improving floodplain conditions.}, language = {en} } @article{CescaMalebranLopezCominoetal.2021, author = {Cesca, Simone and Malebran, Carla Valenzuela and Lopez-Comino, Jose Angel and Davis, Timothy and Tassara, Carlos and Oncken, Onno and Dahm, Torsten}, title = {The 2014 Juan Fernandez microplate earthquake doublet}, series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth}, volume = {801}, journal = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0040-1951}, doi = {10.1016/j.tecto.2021.228720}, pages = {13}, year = {2021}, abstract = {On October 9, 2014, a Mw 7.1-6.7 seismic doublet occurred at the Juan Fernandez microplate, close to the triple junction with Pacific and Nazca plates. The Mw 7.1 earthquake is the largest earthquake ever to have been recorded in the region. Its thrust focal mechanism is also unusual for the region, although the northern part of the microplate is expected to undergo compression. The region is remote and seismological data is limited to a seismic station at similar to 600 km distance on Easter Island and teleseismic observations for the largest events. We use a combination of advanced seismological techniques to overcome the lack of local data and resolve earthquake source parameters for the doublet and its aftershock sequence, being able to reconstruct the chronology of the sequence and the geometry of affected fault segments. Our results depict a complex seismic sequence characterized by the interplay of thrust and strike-slip earthquakes along different structures, including a second, reversed strike slip-thrust seismic doublet in November 2014. Seismicity occurred within the microplate and only in the late part of the sequence migrated northward, towards the microplate boundary. The first largest doublet, whose rupture kinematic is well explained by stress changes imparted by the first subevent on the second one, may have activated unmapped E-W and NE-SW faults or an internal curved pseudofault, attributed to the longterm rotation of the microplate. Few large, thrust earthquakes are observed within the sequence, taking place in the vicinity of mapped compressional ridges. We suggest that compressional stresses in the northern part of the microplate and at its boundary are partially accommodated aseismically. However, the occasional occurrence of large, impulsive thrust earthquakes, with a considerable tsunamigenic potential, poses a relevant hazard for islands in the South Pacific region.}, language = {en} } @article{BuergerHeistermann2023, author = {B{\"u}rger, Gerd and Heistermann, Maik}, title = {Shallow and deep learning of extreme rainfall events from convective atmospheres}, series = {Natural hazards and earth system sciences : NHESS}, volume = {23}, journal = {Natural hazards and earth system sciences : NHESS}, number = {9}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, issn = {1561-8633}, doi = {10.5194/nhess-23-3065-2023}, pages = {3065 -- 3077}, year = {2023}, abstract = {Our subject is a new catalogue of radar-based heavy rainfall events (CatRaRE) over Germany and how it relates to the concurrent atmospheric circulation. We classify daily ERA5 fields of convective indices according to CatRaRE, using an array of 13 statistical methods, consisting of 4 conventional ("shallow") and 9 more recent deep machine learning (DL) algorithms; the classifiers are then applied to corresponding fields of simulated present and future atmospheres from the Coordinated Regional Climate Downscaling Experiment (CORDEX) project. The inherent uncertainty of the DL results from the stochastic nature of their optimization is addressed by employing an ensemble approach using 20 runs for each network. The shallow random forest method performs best with an equitable threat score (ETS) around 0.52, followed by the DL networks ALL-CNN and ResNet with an ETS near 0.48. Their success can be understood as a result of conceptual simplicity and parametric parsimony, which obviously best fits the relatively simple classification task. It is found that, on summer days, CatRaRE convective atmospheres over Germany occur with a probability of about 0.5. This probability is projected to increase, regardless of method, both in ERA5-reanalyzed and CORDEX-simulated atmospheres: for the historical period we find a centennial increase of about 0.2 and for the future period one of slightly below 0.1.}, language = {en} } @article{ShikangalahMapaniMapaureetal.2021, author = {Shikangalah, Rosemary and Mapani, Benjamin and Mapaure, Isaac and Herzschuh, Ulrike}, title = {Responsiveness of Dichrostachys cinerea to seasonal variations in temperature and rainfall in central Namibia}, series = {Flora}, volume = {286}, journal = {Flora}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0367-2530}, doi = {10.1016/j.flora.2021.151974}, pages = {7}, year = {2021}, abstract = {Woody plants provide natural archives of climatic variation which can be investigated by applying dendroclimatological methods. Such studies are limited in Southern Africa but have great potential of improving our understanding of past climates and plant functional adaptations in the region. This study therefore investigated the responsiveness of Dichrostachys cinerea to seasonal variations in temperature and rainfall at two sites in central Namibia, Waterberg and Kuzikus. Dichrostachys cinerea is one of the encroacher species thriving well in Namibia. A moving correlation and response function analysis were used to test its responsiveness to seasonal climatic variations over time. Dichrostachys cinerea growth rings showed relationships to late summer warming, lasting up to half of the rainy season. The results also revealed that past temperatures had been fluctuating and their influence on growth rings had been intensifying over the years, but to varying extents between the two sites. Temperature was a more important determinant of ring growth at the drier site (Kuzikus), while rainfall was more important at the wetter site (Waterberg). Growth ring responsiveness to rainfall was not immediate but showed a rather lagged pattern. We conclude that D. cinerea differentially responds to variations in rainfall and temperature across short climatic gradients. This study showed that the species, due to its somewhat wide ecological amplitude, has great potential for dendroclimatological studies in tropical regions.}, language = {en} } @article{RomeroBarbosaCoelhoScheiffeleetal.2021, author = {Romero Barbosa, Lu{\´i}s and Coelho, Victor Hugo R. and Scheiffele, Lena and Baroni, Gabriele and Ramos Filho, Geraldo M. and Montenegro, Suzana M. G. L. and Das Neves Almeida, Cristiano and Oswald, Sascha}, title = {Dynamic groundwater recharge simulations based on cosmic-ray neutron sensing in a tropical wet experimental basin}, series = {Vadose zone journal : VZJ : advancing critical zone science}, volume = {20}, journal = {Vadose zone journal : VZJ : advancing critical zone science}, number = {4}, publisher = {Wiley}, address = {Hoboken}, issn = {1539-1663}, doi = {10.1002/vzj2.20145}, pages = {22}, year = {2021}, abstract = {Although cosmic-ray neutron sensing (CRNS) is probably the most promising noninvasive proximal soil moisture measurement technique at the field scale, its application for hydrological simulations remains underexplored in the literature so far. This study assessed the use of CRNS to inversely calibrate soil hydraulic parameters at the intermediate field scale to simulate the groundwater recharge rates at a daily timescale. The study was conducted for two contrasting hydrological years at the Guaraira experimental basin, Brazil, a 5.84-km(2), a tropical wet and rather flat landscape covered by secondary Atlantic forest. As a consequence of the low altitude and proximity to the equator low neutron count rates could be expected, reducing the precision of CRNS while constituting unexplored and challenging conditions for CRNS applications. Inverse calibration for groundwater recharge rates was used based on CRNS or point-scale soil moisture data. The CRNS-derived retention curve and saturated hydraulic conductivity were consistent with the literature and locally performed slug tests. Simulated groundwater recharge rates ranged from 60 to 470 mm yr(-1), corresponding to 5 and 29\% of rainfall, and correlated well with estimates based on water table fluctuations. In contrast, the estimated results based on inversive point-scale datasets were not in alignment with measured water table fluctuations. The better performance of CRNS-based estimations of field-scale hydrological variables, especially groundwater recharge, demonstrated its clear advantages over traditional invasive point-scale techniques. Finally, the study proved the ability of CRNS as practicable in low altitude, tropical wet areas, thus encouraging its adoption for water resources monitoring and management.}, language = {en} }