Global maps of soil temperature.

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

Spectroscopic Investigation of a Metal Metal Bonded Fe6 Single Molecule Magnet with an Isolated S 19 2 Giant Spin Ground State

The metal metal bonded molecule [Bu4N][ HL 2Fe6 dmf 2] Fe6 was previously shown to possess a thermally isolated spin S 19 2 ground state and found to exhibit slow magnetization relaxation below a blocking temperature of amp; 8764;5 K [J. Am. Chem. Soc.2015, 137, 13949 13956]. Here, we present a comprehensive spectroscopic investigation of this unique single molecule magnet SMM , combining ultrawideband field swept high field electron paramagnetic resonance EPR with frequency domain Fourier transform terahertz EPR to accurately quantify the spin Hamiltonian parameters of Fe6. Of particular importance is the near absence of a 4th order axial zero field splitting term, which is known to arise because of quantum mechanical mixing of spin states on account of the relatively weak spin spin superexchange interactions in traditional polynuclear SMMs such as the celebrated Mn12 acetate. The combined high resolution measurements on both powder samples and an oriented single crystal provide a quantitative measure of the isolated nature of the spin ground state in the Fe6 molecule, as well as additional microscopic insights into factors that govern the quantum tunneling of its magnetization. This work suggests strategies for improving the performance of polynuclear SMMs featuring direct metal metal bonds and strong ferromagnetic spin spin exchange interaction