Global maps of soil temperature

Jonas J. Lembrechts, Johan van den Hoogen, Juha Aalto, Michael B. Ashcroft, Pieter De Frenne, J. Kemppinen, Martin Kopecký, Miska Luoto, Ilya M. D. Maclean, Thomas W. Crowther, Joseph J. Bailey, Stef Haesen, David H. Klinges, Pekka Oskari Niittynen, Brett R. Scheffers, Koenraad Van Meerbeek, Peter Aartsma, Otar Abdalaze, Mehdi Abedi, Vilna TyystjärviAnnalea Katriina Lohila, Jonathan Lenoir

Research output: Contribution to journalArticleScientificpeer-review

Abstract

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(2) 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(2) 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 degrees C (mean = 3.0 +/- 2.1 degrees 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 degrees C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 +/- 2.3 degrees 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.

Original languageEnglish
JournalGlobal Change Biology
Volume28
Issue number9
Pages (from-to)3110-3144
Number of pages35
ISSN1365-2486
DOIs
Publication statusPublished - May 2022
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1171 Geosciences

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