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Large amounts of time series of spatial snapshot data have been collected or generated for the monitoring and modeling of environmental systems. Those time series of data also provide the opportunity to study the movements and dynamics of many different natural phenomena. While the snapshot organization is conceptually simple and straightforward, it does not directly capture or represent the dynamic characteristics of the phenomena. This study presents computational methods to identify dynamic events from time series of spatial snapshots. Events are represented as directed spatiotemporal graphs to characterize their initiation, development, movement, and cessation. Graph-based algorithms are used to analyze the dynamics of the events. The method is applied to time series of high-resolution radar reflectivity images during one of the deadliest storm outbreaks that impacted 15 states of southeastern United States between 23 and 29 April 2011. As shown in this case study, convective storm events identified using our methods are consistent with previous studies, and our analysis confirms that the left split/merger occurs more than right split/merger in those convective storm events, which confirms theory, numerical simulations, and other observed case studies. While this study does not differentiate between storm modes, the method shows potential for capturing a more detailed climatology of precipitation characteristics. [ABSTRACT FROM AUTHOR]

The sediment yield model of the MUSLE (modified universal soil loss equation) is applied extensively throughout the world, but different performances have been reported of its success relative to measured data. A review of all the available literature is presented to assess the application of the model under different conditions and, ultimately, make a comprehensive judgement on the different aspects to allow readers to adjust their further research. A review of 49 papers showed the variable accuracy of the model, which depends on the manner of calculation and determination of the input and output, and the study time and space scales. There were differences in land use, in correspondence of the physiographic characteristics with those of the original conditions of model development, and even in the experience of researchers in applying the model. The results also show the need to consider the original application of the model, as proposed by its developers, to achieve comparable results. EditorZ.W. Kundzewicz CitationSadeghi, S.H.R.,et al., 2014. A review of the application of the MUSLE model worldwide.Hydrological Sciences Journal, 59 (2), 365–375. [ABSTRACT FROM PUBLISHER]

The bioavailability of catchment-derived particulate phosphorus (PP) to lentic phytoplankton was investigated. Two stream inflows to Lake Rotorua (Bay of Plenty, New Zealand) were sampled during moderate (March) and large (August) discharge peaks in 2012. Phosphorus (P) fractions in samples were quantified and a bioassay was undertaken using samples from the March event to determine whether P-limited phytoplankton could utilise PP. Phosphorus composition differed markedly between events but was comparable between streams. For the March event, all PP (persulphate extractable) was bioavailable if exposed to anoxia, whereas c. 25% was potentially bioavailable for the August event. Despite this, the laboratory bioassay indicated that, under oxic conditions, suspended sediments acted as a sink rather than a source of bioavailable P to P-limited phytoplankton. This study highlights the importance of considering P speciation and the nature of the receiving environment when assessing the bioavailability of P transported through hydrological landscapes. [ABSTRACT FROM PUBLISHER]

The effectiveness of best management practices (BMPs) at preventing erosion and controlling storm water and sediment runoff in developing catchments in the Reedy River (South Carolina) watershed was evaluated from 2004 to 2005. Catchment-normalized storm Water runoff and event mean concentrations and cumulative mass loads of selected pollutants were compared among four catchments exhibiting similar rainfall, soil, and geographic characteristics but undergoing varying degrees of development. Despite the implementation of BMPs, streams below catchments undergoing active development exhibited patterns characteristic of urbanized watersheds, namely, storm hydrographs characterized by steep rising and descending limbs due to accelerated storm water runoff. In contrast with the developing catchments, streams below relatively undisturbed catchments exhibited more gradual rising and descending limbs on their hydrographs, presumably due to enhanced infiltration and interflow and less direct surface runoff. A comparison of surface runoff depths and runoff ratios confirmed more direct surface runoff was generated from rainfall in the developing catchments versus the undisturbed catchments despite the use of BMPs. In addition, area-normalized maximum stream discharges during storm events were generally higher for the developing versus undisturbed catchments. Similarly, mean concentrations and mass loads of total suspended solids were consistently higher for the developing versus undisturbed catchments. In many cases, mean concentrations for total suspended solids and other selected pollutants in storm water runoff from the developing catchments exceeded recognized water quality criteria. Taken together, the quantity and quality of storm water runoff from the developing catchments indicate that the overall protective goals of erosion prevention and sediment control regulations are not being met. Possible explanations for this include BMPs that have not been properly designed or located, are not the correct type, are insufficiently numerous, and/or have not been adequately maintained to control the increased surface runoff and/or soil erosion due to land disturbance. Alternatively, the failure may reflect shortcomings in the regulations themselves. [ABSTRACT FROM AUTHOR]

The reforested headwater watersheds in Japan are very important from the points of view of commercial and environmental aspects. At the present time, much and varied research is running to assess and understand the hydrologic behavior of these watersheds. The present study was conducted to evaluate the applicability of the deterministic model MUSLE in the Mie small steeply reforested watershed. The model was tested and calibrated using accurate continuous suspended sediment data collected during eight storm events in 2004. Results of the original model simulations for storm-wise sediment yield did not match the observed data, while the revised version of the model could imitate the observed values well. The results of the study approved the efficient application of the revised MUSLE in estimating storm-wise sediment yield in the study area with a high level of agreement of beyond 88%, an acceptable estimation error of some 14% and non-significant difference in mean values. [ABSTRACT FROM AUTHOR]

An X-band nautical radar system was employed to observe the wave field during a storm around the research pier HORS in Hasaki, Japan. The radar system provides instantaneous distributions of wave crests in the near-shore region, with image sequences comprising a clear spatial and temporal variation of the wave pattern. The spectra of radar echo signals and water surface elevations from wave gauge records were compared, and a relatively high coherence for a particular bandwidth was observed. A sequence of radar images was filtered at the dominant frequency, which was used to estimate the wavenumber distribution of the refraction field. The Fast Fourier Transform (FFT) and Maximum Entropy Method (MEM) were used to estimate the wavenumbers. The estimated wave angles were then compared with linear refraction analyses. The water depths along the pier were also estimated using the linear dispersion relationship and compared with the surveyed depths. The linear estimates of hydrodynamic parameters during the passage of the storm are presented in this paper to demonstrate the potential of radar measurements in capturing essential characteristics of coastal dynamics. [ABSTRACT FROM AUTHOR]