Fine-scale Events Research Articles

Severe floods predictive ability: A proxy based probabilistic assessment of the Italian early warning system

AbstractIn compliance with the national legal framework, the regional offices (CFDs) of the Italian Civil Protection Department have the daily duty to issue warnings to the local population on the account of the weather and hydrology‐related impacts, predicted by forecast models and refined through their expertise and experience: this composite of objective (model) and subjective (analyst) assessments are both contributing to the actual colour‐coded warning system. Given its hybrid nature, it is of paramount importance to evaluate the predictive ability of the warning decision‐making process as a whole. To this end, this study compares the return period T of the occurred flood (estimated through an hydrological model fed with observations) to the warning level that was issued. The novelty of this approach is that, by applying this methodology extensively in space and time, the probability curves of the variable T for each warning level are computed, allowing to evaluate the consistency between the warnings and the actual (estimated) severity of the event. As results suggest, the national early warning system is proven to be overall reliable for most cases, though very fine scale events (e.g., severe, localised, short‐lived thunderstorms) are still an open challenge.

Aerial Drone Imaging in Alongshore Marine Ecosystems: Small-Scale Detection of a Coastal Spring System in the North-Eastern Adriatic Sea

The eastern coastline of the Gulf of Trieste (north-eastern Adriatic Sea, Italy) is characterized by the occurrence of coastal and submarine freshwater springs of karstic origin. In one of these areas, we performed a survey with a drone with a thermal camera installed, in tandem with in situ oceanographic sampling with a CTD. Drone images revealed a small time-space scale (i.e., up to a few meters) phenomenon of freshwater plumes floating over seawater. Comparing sea surface temperature data with those acquired in situ revealed that the phenomenon was not clearly detectable by the classical oceanographic monitoring, this surface spring freshwater layer being too thin. Instead, the drone’s thermal camera detected these dynamics with great accuracy, indicating that aerial drones can be efficiently used for studying fine-scale events involving surface waters (e.g., spills/pollution). The experience gained allowed us to discuss some of the advantages and disadvantages of using drone thermal imaging for monitoring alongshore areas.

Evaluation of Gridded Meteorological Datasets for Hydrological Modeling

Abstract The number and refinement of gridded meteorological datasets are on the rise at the global and regional scales. Although these datasets are now commonly used for hydrological modeling, the representation of precipitation amount and timing is crucial to correctly model streamflow. The Génie Rural à 4 paramètres journalier (GR4J) conceptual hydrological model combined with the CEMANEIGE snow routine was calibrated using four temperature and precipitation datasets [Système d’analyse fournissant des renseignements atmosphériques à la neige (SAFRAN), Mesoscale Analysis (MESAN), E-OBS, and Water and Global Change (WATCH) Forcing Data ERA-Interim (WFDEI)] on 931 French gauged catchments ranging in size from 10 to 10 000 km2. The efficiency of the calibrated hydrological model in simulating streamflow was higher for the models calibrated on high-resolution meteorological datasets (SAFRAN, MESAN) compared to coarse-resolution datasets (E-OBS, WFDEI), as well as for reanalysis (SAFRAN, MESAN, WFDEI) compared to datasets based on interpolation only (E-OBS). The systematic decrease in efficiency associated with precipitation bias or temporality highlights that the use of a hydrological model calibrated on meteorological datasets can assess these datasets, most particularly precipitation. It appears essential that datasets account for high-resolution topography to accurately represent elevation gradients and assimilate dense ground-based observation networks. This is particularly emphasized for hydrological applications in mountainous areas and areas subject to finescale events. For hydrological applications on nonmountainous regions, not subject to finescale events, both regional and global datasets give satisfactory results. It is crucial to continue improving precipitation datasets, especially in mountainous areas, and to assess their sensitivity to eventual corrupted observations. These datasets are essential to correct the bias of climate model outputs and to investigate the impact of climate change on hydrological regimes.

Testing and deployment of C-VISS (cetacean-borne video camera and integrated sensor system) on wild dolphins

Multi-sensor biologgers are a powerful method for studying individual behaviors of free-ranging species, yet the challenges of attaching non-invasive biologgers to agile, fast-moving marine species have prohibited application of this technique to small (<5 m) cetaceans. Integration of video cameras into such biologgers is critical to understanding behavior from the animal’s perspective; however, this technique has not been applied to small cetaceans. We examined the feasibility of remotely deploying a cetacean-borne video camera and integrated sensor system (“C-VISS”) on small cetaceans. We deployed C-VISS on eight free-swimming dusky dolphins (Lagenorhynchus obscurus) off New Zealand (42°25′15″S 173°40′23″E) from December 2015 to January 2016, collecting a total of 535 min of video footage (average = 66.8 ± 91.10 SD, range 9–284). Dolphins were observed to show limited reactions to biologger attachment attempts and deployments. Social and environmental parameters derived from video footage include conspecific body condition, mother-calf spatial positioning, affiliative behavior, sexual behavior, sociability, prey, and habitat type. The ability to record behavioral states and fine-scale events from the individual’s perspective will yield new insights into the behavior, socioecology, conservation, rehabilitation, and welfare of small cetaceans.

Temperature and light patterns at four reefs along the Great Barrier Reef during the 2015–2016 austral summer: understanding patterns of observed coral bleaching

ABSTRACTData from real-time sensor networks along the Great Barrier Reef (GBR) over the 2015–2016 austral summer showed that reef water temperatures exceeded empirical coral bleaching thresholds at a number of sites. Temperatures in the southern GBR were within historically normal limits with temperatures below the empirical bleaching threshold. The central GBR just reached the empirical bleaching threshold while, in the north, Lizard Island recorded four consecutive days above the bleaching threshold. Thursday Island in the far northern GBR experienced 10 days above the bleaching threshold. The in situ data predicted only slight bleaching in the southern GBR, moderate bleaching in the central GBR, widespread bleaching in the north and severe bleaching in the far north, which compares well with the initial survey data. Peak temperatures occurred later in the year in the north (mid-March 2016) than in the south (early February 2015) with temperatures remaining above the long-term mean well into the austral autumn. Comparison against satellite sea surface temperature data highlighted issues of cloud cover with data only being available for 30–40% of days over the summer. While the agreement with the in situ data was good, the satellite data missed fine-scale events and under-estimated the event at Thursday Island.

Microbial mediated arsenic biotransformation in wetlands

Arsenic (As) is a pervasive environmental toxin and carcinogenic metalloid. It ranks at the top of the US priority List of Hazardous Substances and causes worldwide human health problems. Wetlands, including natural and artificial ecosystems (i.e. paddy soils) are highly susceptible to As enrichment; acting not only as repositories for water but a host of other elemental/chemical moieties. While macroscale processes (physical and geological) supply As to wetlands, it is the micro-scale biogeochemistry that regulates the fluxes of As and other trace elements from the semi-terrestrial to neighboring plant/aquatic/atmospheric compartments. Among these fine-scale events, microbial mediated As biotransformations contribute most to the element’s changing forms, acting as the ‘switch’ in defining a wetland as either a source or sink of As. Much of our understanding of these important microbial catalyzed reactions follows relatively recent scientific discoveries. Here we document some of these key advances, with focuses on the implications that wetlands and their microbial mediated transformation pathways have on the global As cycle, the chemistries of microbial mediated As oxidation, reduction and methylation, and future research priorities areas.

Uncertainty analysis and robust optimization of multiscale process systems with application to epitaxial thin film growth

Multiscale modeling of materials growth involves inherently coupled processes that span over a wide range of time and length scales. As a common practice, a multiscale model is adopted to simulate the thin film deposition process that augments Partial Differential Equations (PDEs), describing the macro-scale phenomena, with a high-order lattice-based kinetic Monte Carlo (KMC) simulator, which aims to capture thin film microstructure. Although such a model is a fair representation of the system, the evolution of thin film encompasses processes that are subject to model parameter uncertainty that can significantly affect the control and optimization objectives of this process, e.g. film׳s roughness and thickness. Thus, to provide a robust and more realistic strategy, it is crucial to perform an uncertainty analysis for this process. This work explores a systematic framework to analyze model parameter uncertainty for robust control and optimization of multiscale models. Such an analysis is extremely challenging due to (i) the lack of a closed formulation between the process optimization objective (i.e. film thickness) and the model parameters and (ii) the computational costs incurred to model the fine-scale events, typically performed using KMC simulation. To tackle these challenges, Power Series Expansion (PSE) is employed to analyze model uncertainty propagation. The PSE-based method for uncertainty analysis is more computationally efficient in comparison to the traditional Monte Carlo approach. The distributional uncertainty in rates of microscopic events is characterized by series expansions of the uncertain parameters. The fitted distributions to the rate of events at a given confidence level are employed to estimate upper and lower bounds on the desired outputs (e.g. film roughness). The computational efficiency of the approach is achieved by employing multiple reduced-order lattices in the KMC simulator. The potential application of the proposed method is illustrated through an optimization problem that aims to specify the robust optimal substrate temperature profile that maximizes the endpoint thin film thickness in the presence of uncertainty.

Genome-scale analysis of positionally relocated genes

During evolution, genome reorganization includes large-scale events such as inversions, translocations, and segmental or even whole-genome duplications, as well as fine-scale events such as the relocation of individual genes. This latter category, which we will refer to as positionally relocated genes (PRGs), is the subject of this report. Assessment of the magnitude of such PRGs and of possible contributing mechanisms is aided by a comparative analysis of related genomes, where conserved chromosomal organization can aid in identifying genes that have acquired a new location in a lineage of these genomes. Here we utilize two methods to comprehensively identify relocated protein-coding genes in the recently sequenced genomes of 12 species of genus Drosophila. We use exceptions to the general rule of maintenance of chromosome arm (Muller element) association for most Drosophila genes to identify one major class of PRGs. We also identify a partially overlapping set of PRGs among "embedded genes," located within the extents of other surrounding genes. We provide evidence that PRG movements have at least two different origins: Some events occur via retrotransposition of processed RNAs and others via a DNA-based transposition mechanism. Overall, we identify several hundred PRGs that arose within a lineage of the genus Drosophila phylogeny and provide suggestive evidence that a few thousand such events have occurred within the radiation of the insect order Diptera, thereby illustrating the magnitude of the contribution of PRG movement to chromosomal reorganization during evolution.

A DYNAMICAL SYSTEM FOR NEIGHBORHOODS INPLANT COMMUNITIES

How should plant ecologists scale up from the fine-scale events affecting individual plants in small neighborhoods to the coarse-scale dynamics of plant communities? We give here a dynamical system, derived from an individual-based model, that captures the main effects of spatial structure. The individual-based model describes a multispecies plant community, living in a spatial domain, containing plants that (1) reproduce and die with rates that depend on other individuals in a specified neighborhood, and (2) move through seed dispersal and clonal growth. Over the course of time, substantial spatial structure can build up in such a community due to local interactions and dispersal. The dynamical system describes how the structure of local neighborhoods changes over time, using the first and second spatial moments of the individual-based model. We show, by means of an example of two competing species, that the dynamical system gives a close approximation to the behavior of the underlying individual-based model, and that the chang- es in local spatial structure as time progresses have fundamental effects on the dynamics.

The demonstration of speciation in fossil molluscs and living fishes

Contrary to a recent assertion, freshwater (and marine) prosobranch gastropods and freshwater bivalves are subject to considerable variability. This, and the lack of a detailed understanding of the taxonomy of the forms involved, makes it difficult to accept that the changes documented by Williamson (1981) in a fossil sequence from Lake Turkana (Africa) represent speciation events. That 10 lineages, involving gastropods and bivalves, should change simultaneously, and the deviant forms should then simultaneously become extinct, can, we believe, be more plausibly attributed to ecophenotypic responses to environmental changes than to speciation. In revealing the pattern and process of evolution, both fossil and living forms are helpful, but in demonstrating the fine-scale events during and after speciation in living animals one can utilize techniques and observations that cannot be applied to fossil material. African cichlid fishes are particularly informative in this respect. Their current explosive radiation can be interpreted as a punctuational event in evolution.