@misc{PoradaTammRaggioetal.2019, author = {Porada, Philipp and Tamm, Alexandra and Raggio, Jose and Yafang, Cheng and Kleidon, Axel and P{\"o}schl, Ulrich and Weber, Bettina}, title = {Global NO and HONO emissions of biological soil crusts estimated by a process-based non-vascular vegetation model}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {746}, issn = {1866-8372}, doi = {10.25932/publishup-43568}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-435682}, pages = {2003 -- 2031}, year = {2019}, abstract = {The reactive trace gases nitric oxide (NO) and nitrous acid (HONO) are crucial for chemical processes in the atmosphere, including the formation of ozone and OH radicals, oxidation of pollutants, and atmospheric self-cleaning. Recently, empirical studies have shown that biological soil crusts are able to emit large amounts of NO and HONO, and they may therefore play an important role in the global budget of these trace gases. However, the upscaling of local estimates to the global scale is subject to large uncertainties, due to unknown spatial distribution of crust types and their dynamic metabolic activity. Here, we perform an alternative estimate of global NO and HONO emissions by biological soil crusts, using a process-based modelling approach to these organisms, combined with global data sets of climate and land cover. We thereby consider that NO and HONO are emitted in strongly different proportions, depending on the type of crust and their dynamic activity, and we provide a first estimate of the global distribution of four different crust types. Based on this, we estimate global total values of 1.04 Tg yr⁻¹ NO-N and 0.69 Tg yr⁻¹ HONO-N released by biological soil crusts. This corresponds to around 20\% of global emissions of these trace gases from natural ecosystems. Due to the low number of observations on NO and HONO emissions suitable to validate the model, our estimates are still relatively uncertain. However, they are consistent with the amount estimated by the empirical approach, which confirms that biological soil crusts are likely to have a strong impact on global atmospheric chemistry via emissions of NO and HONO.}, language = {en} } @article{PoradaTammRaggioetal.2019, author = {Porada, Philipp and Tamm, Alexandra and Raggio, Jose and Yafang, Cheng and Kleidon, Axel and P{\"o}schl, Ulrich and Weber, Bettina}, title = {Global NO and HONO emissions of biological soil crusts estimated by a process-based non-vascular vegetation model}, series = {Biogeosciences}, volume = {16}, journal = {Biogeosciences}, publisher = {Copernicus Publ.}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-16-2003-2019}, pages = {2003 -- 2031}, year = {2019}, abstract = {The reactive trace gases nitric oxide (NO) and nitrous acid (HONO) are crucial for chemical processes in the atmosphere, including the formation of ozone and OH radicals, oxidation of pollutants, and atmospheric self-cleaning. Recently, empirical studies have shown that biological soil crusts are able to emit large amounts of NO and HONO, and they may therefore play an important role in the global budget of these trace gases. However, the upscaling of local estimates to the global scale is subject to large uncertainties, due to unknown spatial distribution of crust types and their dynamic metabolic activity. Here, we perform an alternative estimate of global NO and HONO emissions by biological soil crusts, using a process-based modelling approach to these organisms, combined with global data sets of climate and land cover. We thereby consider that NO and HONO are emitted in strongly different proportions, depending on the type of crust and their dynamic activity, and we provide a first estimate of the global distribution of four different crust types. Based on this, we estimate global total values of 1.04 Tg yr⁻¹ NO-N and 0.69 Tg yr⁻¹ HONO-N released by biological soil crusts. This corresponds to around 20\% of global emissions of these trace gases from natural ecosystems. Due to the low number of observations on NO and HONO emissions suitable to validate the model, our estimates are still relatively uncertain. However, they are consistent with the amount estimated by the empirical approach, which confirms that biological soil crusts are likely to have a strong impact on global atmospheric chemistry via emissions of NO and HONO.}, language = {en} } @article{PoradaVanStanKleidon2018, author = {Porada, Philipp and Van Stan, John T. and Kleidon, Axel}, title = {Significant contribution of non-vascular vegetation to global rainfall interception}, series = {Nature geoscience}, volume = {11}, journal = {Nature geoscience}, number = {8}, publisher = {Nature Publ. Group}, address = {New York}, issn = {1752-0894}, doi = {10.1038/s41561-018-0176-7}, pages = {563 -- +}, year = {2018}, abstract = {Non-vascular vegetation has been shown to capture considerable quantities of rainfall, which may affect the hydrological cycle and climate at continental scales. However, direct measurements of rainfall interception by non-vascular vegetation are confined to the local scale, which makes extrapolation to the global effects difficult. Here we use a process-based numerical simulation model to show that non-vascular vegetation contributes substantially to global rainfall interception. Inferred average global water storage capacity including non-vascular vegetation was 2.7 mm, which is consistent with field observations and markedly exceeds the values used in land surface models, which average around 0.4 mm. Consequently, we find that the total evaporation of free water from the forest canopy and soil surface increases by 61\% when non-vascular vegetation is included, resulting in a global rainfall interception flux that is 22\% of the terrestrial evaporative flux (compared with only 12\% for simulations where interception excludes non-vascular vegetation). We thus conclude that non-vascular vegetation is likely to significantly influence global rainfall interception and evaporation with consequences for regional-to continental-scale hydrologic cycling and climate.}, language = {en} }