Why has catchment evaporation increased in the past 40 years? A data-based study in Austria Hydrology and Earth System Sciences DOI 10.5194/hess-22-5143-2018 4 October 2018 We analyze changes in catchment evaporation estimated from the water balances of 156 catchments in Austria over 1977–2014, as well as the possible causes of these changes. Our results show that catchment evaporation increased on average by 29 ± 14 mm yr−1 decade−1. We attribute this increase to changes in atmospheric demand (based on reference and pan evaporation), changes in vegetation (quantified by a satellite-based vegetation index), and changes in precipitation. Read more
Trends in China’s anthropogenic emissions since 2010 as the consequence of clean air actions Atmospheric Chemistry and Physics DOI 10.5194/acp-18-14095-2018 4 October 2018 To tackle the problem of severe air pollution, China has implemented active clean air policies in recent years. We quantified China’s anthropogenic emissions during 2010–2017 and identified the major driving forces of these trends by using a combination of bottom-up emission inventory and index decomposition analysis (IDA) approaches. The major air pollutants have reduced their emissions by 17–62 % during 2010–2017. The IDA results suggest that emission control measures are the main drivers. Read more
Potential for phenol biodegradation in cloud waters Biogeosciences DOI 10.5194/bg-15-5733-2018 28 September 2018 The main objective of this work was to evaluate the potential degradation of phenol, a highly toxic pollutant, by cloud microorganisms. Phenol concentrations measured on five cloud samples collected at the PUY station in France were from 0.15 to 0.74 µg L−1. Metatranscriptomic analysis suggested that phenol could be biodegraded directly in clouds, likely by Gammaproteobacteria. A large screening showed that 93 % of 145 bacterial strains isolated from clouds were able to degrade phenol. Read more
How well do stratospheric reanalyses reproduce high-resolution satellite temperature measurements? Atmospheric Chemistry and Physics DOI 10.5194/acp-18-13703-2018 27 September 2018 Reanalyses (RAs) are models which assimilate observations and are widely used as proxies for the true atmospheric state. Here, we resample six leading RAs using the weighting functions of four high-res satellite instruments, allowing a like-for-like comparison. We find that the RAs generally reproduce the satellite data well, except at high altitudes and in the tropics. However, we also find that the RAs more tightly correlate with each other than with observations, even those they assimilate. Read more
Global 5 km resolution estimates of secondary evaporation including irrigation through satellite data assimilation Hydrology and Earth System Sciences DOI 10.5194/hess-22-4959-2018 27 September 2018 Evaporation from wetlands, lakes and irrigation areas needs to be measured to understand water scarcity. So far, this has only been possible for small regions. Here, we develop a solution that can be applied at a very high resolution globally by making use of satellite observations. Our results show that 16% of global water resources evaporate before reaching the ocean, mostly from surface water. Irrigation water use is less than 1% globally but is a very large water user in several dry basins. Read more
World Ocean Circulation Experiment – Argo Global Hydrographic Climatology Ocean Science DOI 10.5194/os-14-1127-2018 27 September 2018 The new gridded WOCE-Argo Global Hydrographic Climatology (WAGHC) is described and compared with the NOAA WOA13 atlas. The monthly fields of temperature and salinity for 65 depth levels have a 1/4° spatial resolution. Two versions of the climatology were produced and differ with respect to the spatial interpolation performed on isobaric or isopycnal surfaces, respectively. The climatology characterizes the thermohaline state of the world ocean for the time period from 2008 to 2012. Read more
Cleaning up our water: reducing interferences from nonhomogeneous freezing of “pure” water in droplet freezing assays of ice-nucleating particles Atmospheric Measurement Techniques DOI 10.5194/amt-11-5315-2018 24 September 2018 Ice nucleation commonly studied using droplet freezing measurements suffers from artifacts caused by water impurities or substrate effects. We evaluate a series of substrates and water sources to find methods that reduce the background freezing temperature limit. The best performance was obtained from our new microfluidic device and hydrophobic glass surfaces, using filtered HPLC bottled water. We conclude with recommendations for best practices in droplet freezing experiments and data analysis. Read more
Diurnal land surface energy balance partitioning estimated from the thermodynamic limit of a cold heat engine Earth System Dynamics DOI 10.5194/esd-9-1127-2018 21 September 2018 Turbulent fluxes represent an efficient way to transport heat and moisture from the surface into the atmosphere. Due to their inherently highly complex nature, they are commonly described by semiempirical relationships. What we show here is that these fluxes can also be predicted by viewing them as the outcome of a heat engine that operates between the warm surface and the cooler atmosphere and that works at its limit. Read more
Stopping the flood: could we use targeted geoengineering to mitigate sea level rise? The Cryosphere DOI 10.5194/tc-12-2955-2018 20 September 2018 In this paper, we explore the possibility of using locally targeted geoengineering to slow the rate of an ice sheet collapse. We find that an intervention as big as existing large civil engineering projects could have a 30 % probability of stopping an ice sheet collapse, while larger interventions have better odds of success. With more research to improve upon the simple designs we considered, it may be possible to perfect a design that was both achievable and had good odds of success. Read more
Tracing water masses with 129I and 236U in the subpolar North Atlantic along the GEOTRACES GA01 section Biogeosciences DOI 10.5194/bg-15-5545-2018 18 September 2018 The investigation of water mass transport pathways and timescales is important to understand the global ocean circulation. Following earlier studies, we use artificial radionuclides introduced to the oceans in the 1950s to investigate the water transport in the subpolar North Atlantic (SPNA). For the first time, we combine measurements of the long-lived iodine-129 and uranium-236 to confirm earlier findings/hypotheses and to better understand shallow and deep ventilation processes in the SPNA. Read more
