71 research outputs found

    On thin plate spline interpolation

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    We present a simple, PDE-based proof of the result [M. Johnson, 2001] that the error estimates of [J. Duchon, 1978] for thin plate spline interpolation can be improved by h1/2h^{1/2}. We illustrate that H{\mathcal H}-matrix techniques can successfully be employed to solve very large thin plate spline interpolation problem

    Global maps of soil temperature.

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    Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km <sup>2</sup> resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km <sup>2</sup> pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

    Direct democracy catalysed by resident-to-resident online deliberation

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    In the context of local civic governance, much of the interest in e-Participation concerns the extent to which online media might overcome the limitations of geography and scale, and so allow local interests to be better represented in institutionally driven participatory processes at national or regional level. In contrast, this study investigates the online deliberations of a local, geographically bounded community in a series of mailing lists that had originated from their own initiative and self-organisation. The interactions we observe challenges assumptions of democratic deliberation as mainly policy debate between citizens and government, or of lobbying administrative government. It also proposes a broader conception of the role of online deliberation in local governance, where instrumental decision-making and developing consensus is frequently over privileged in research
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