Ideal width of transects for monitoring source-related categories of plastics on beaches

Although there is a consensus on the necessity of monitoring solid wastes pollution on beaches, the methods applied vary widely. Therefore, creating, testing and recommending a method that not only allows comparisons of places and periods, but also the detection of source signals, will be important to reach the objectives of the source-prevention principle. This will also allow the optimisation of time, resources, and processing of samples and data. A classification of the items found into specific categories was made according to their most probable source/use (fisheries, food packaging, hazardous, sewage/personal hygiene, beach user, general home). This study tested different widths of sampling transects to be used in the detection of plastics contamination on beaches, until all the categories were significantly represented. Each transect had its total width (50m) sub-divided into eight intervals of 0-2.5m; 2.5-5m; 5-10m; 10-15m; 15-20m; 20-30m; 30-40m; and 40-50m. The accumulated number of categories in the 50m (up to 2.5m; up to 5m and so on) was used to determine the minimal width necessary to qualitatively characterize the area regarding plastics contamination. The diversity of the categories was directly related to the area of the sampling transect. These results indicate that a significant increase in the number of categories in the first intervals tend to stabilize from 15-20m onwards.     

Effects of the number of stations and time resolution on derivation

For at least 30 years now it has been well known that the Dst index can be modelled using the solar wind as input. Since then, many attempts have been made to improve the predictability of Dst using different approaches. These attempts are useful, for instance, to understand which features of the solar wind–magnetosphere interactions are most important in producing magnetospheric activity and how the Dst index would improve the space weather forecast. The Dst index is by far the most reliable and simple indication that a magnetic storm is in progress. In this work, the effect of using more than four magnetic stations and shorter time intervals than the hourly averages used in Sugiura's procedures is evaluated. The discussion is based on the results presented by Burton in 1975 and Feldstein in 1984 considering 4 or 12 magnetic stations and time averages of 2.5 min for a magnetic disturbed period that occurred from February 7–28, 1967, including two geomagnetic storms. The analysis has shown that the global representation of a magnetic storm by the standard Dst (Sugiura) is well preserved either using 4, 6, 12 magnetic stations or using 1 h, 2.5 min 1 min averages. A brief review of the current understanding of Dst has been included to support the discussions. The analysis performed has shown that a more refined Dst index (time and number of stations>4) would be useful to investigate the intrinsic processes and the different current systems involved in the ring current development during magnetic storms; the standard Dst, as it is conceived, is quite adequate to monitor geomagnetic storms and identify their overall features; concerning the magnetic stations normally considered, the inclusion of higher magnetic latitude stations (>35) may underestimate the observed Dst.     

A multi-proxy approach for revealing recent climatic changes in the Russian Altai

For the first time we present a multi-proxy data set for the Russian Altai, consisting of Siberian larch tree-ring width (TRW), latewood density (MXD), δ¹³C and δ¹⁸O in cellulose chronologies obtained for the period 1779–2007 and cell wall thickness (CWT) for 1900–2008. All of these parameters agree well between each other in the high-frequency variability, while the low-frequency climate information shows systematic differences. The correlation analysis with temperature and precipitation data from the closest weather station and gridded data revealed that annual TRW, MXD, CWT, and δ¹³C data contain a strong summer temperature signal, while δ¹⁸O in cellulose represents a mixed summer and winter temperature and precipitation signal. The temperature and precipitation reconstructions from the Belukha ice core and Teletskoe lake sediments were used to investigate the correspondence of different independent proxies. Low frequency patterns in TRW and δ¹³C chronologies are consistent with temperature reconstructions from nearby Belukha ice core and Teletskoe lake sediments showing a pronounced warming trend in the last century. Their combination could be used for the regional temperature reconstruction. The long-term δ¹⁸O trend agrees with the precipitation reconstruction from the Teletskoe lake sediment indicating more humid conditions during the twentieth century. Therefore, these two proxies could be combined for the precipitation reconstruction.     

A case study of atmospheric boundary layer features during winter over a tropical inland station — Kharagpur (22.32°N, 87.32°E)

The local weather and air quality over a region are greatly influenced by the atmospheric boundary layer (ABL) structure and dynamics. ABL characteristics were measured using a tethered balloon-sonde system over Kharagpur (22.32°N, 87.32°E, 40m above MSL), India, for the period 7 December 2004 to 30 December 2004, as a part of the Indian Space Research Organization-Geosphere Biosphere Program (ISRO-GBP) Aerosol Land Campaign II. High-resolution data of pressure, temperature, humidity, wind speed and wind direction were archived along with surface layer measurements using an automatic weather station. This paper presents the features of ABL, like ABL depth and nocturnal boundary layer (NBL) depth. The sea surface winds from Quikscat over the oceanic regions near the experiment site were analyzed along with the NCEP/NCAR reanalysis winds over Kharagpur to estimate the convergence of wind, moisture and vorticity to understand the observed variations in wind speed and relative humidity, and also the increased aerosol concentrations. The variation of ventilation coefficient (V C), a factor determining the air pollution potential over a region, is also discussed in detail.     

Correction to: Spatial distribution and estimation of rainfall trends and erosivity in the Epitácio Pessoa reservoir catchment,Paraíba,Brazil

Natural Hazards - The article “Spatial distribution and estimation of rainfall trends and erosivity in the Epitácio Pessoa reservoir catchment, Paraíba, Brazil”, written by da...     

Multiple Random Walk Simulation: A Fast Method to Map Grade Uncertainty with Large Datasets

Multiple Random Walk Simulation consists of a methodology adapted to run fast simulations if close-spaced data are abundant (e.g., short-term mining models). Combining kriging with the simulation of random walks attempts to approximate traditional simulation algorithm results but at a computationally faster way when there is a large amount of conditioning samples. This paper presents this new algorithm illustrating the situations where the method can be used properly. A synthetic study case is presented in order to illustrate the Multiple Random Walk Simulation and to analyze the speed and goodness of its results against the ones from using Turning Bands Simulation and Sequential Gaussian Simulation.     

Is LkHα 264 like a young, extremely active Sun?

We combine calibrated International Ultraviolet Explorer ( IUE ) archive data and new low-resolution optical data for the T Tauri star LkH α 264 covering the region from 1200 to 7000 Å. The UV continuum is well fitted by the combination of a blackbody at 4300 K plus hydrogenic free–free and free–bound emission from a dense plasma at 3.5×10⁴ K plus the emission by a second blackbody. This last component is at T ≈8700 K and covers about 4 per cent of the stellar surface. We interpret this last component to be the result of emission from one or various hotspots. The interesting result is that this combined emission also fits the observed optical continuum well. We conclude that this star is an analogue of the Sun, however displaying a much higher level of activity.     

Highly nonlinear wind waves in Currituck Sound: dense breather turbulence in random ocean waves

Ocean Dynamics - We analyze surface wave data taken in Currituck Sound, North Carolina, during a storm on 4 February 2002. Our focus is on the application of nonlinear Fourier analysis (NLFA)...