On the similarity and apparent cycles of isotopic variations in East Antarctic snow pits The Cryosphere DOI 10.5194/tc-12-169-2018 17 January 2018 We explain why snow pits across different sites in East Antarctica show visually similar isotopic variations. We argue that the similarity and the apparent cycles of around 20 cm in the δD and δ18O variations are the result of a seasonal cycle in isotopes, noise, for example from precipitation intermittency, and diffusion. The near constancy of the diffusion length across many ice-coring sites explains why the structure and cycle length is largely independent of the accumulation conditions. Read more
A machine learning calibration model using random forests to improve sensor performance for lower-cost air quality monitoring Atmospheric Measurement Techniques DOI 10.5194/amt-11-291-2018 15 January 2018 Low-cost sensors promise neighborhood-scale air quality monitoring but have been plagued by inconsistent performance for precision, accuracy, and drift. CMU and SenSevere collaborated to develop the RAMP, which uses electrochemical sensors. We present a machine learning algorithm that overcomes previous performance issues and meets US EPA’s data quality recommendations for personal exposure for NO2and tougher “supplemental monitoring” standards for CO&ozone across 19 RAMPs for several months. Read more
Agricultural ammonia emissions in China: reconciling bottom-up and top-down estimates Atmospheric Chemistry and Physics DOI 10.5194/acp-18-339-2018 12 January 2018 Substantial differences exist in current estimates of agricultural ammonia emissions in China, hindering understanding of their environmental consequences. This study applies both bottom-up and top-down methods to better quantify agricultural ammonia sources in China using observations from satellite and surface networks interpreted by a chemical transport model. Our estimate of annual Chinese anthropogenic ammonia emission is 11.7 tg (teragram) for 2008 with a strong seasonality peak in summer. Read more
Temporal variability of tidal and gravity waves during a record long 10-day continuous lidar sounding Atmospheric Chemistry and Physics DOI 10.5194/acp-18-371-2018 12 January 2018 Gravity waves (GWs) as well as solar tides are a key driving mechanism for the circulation in the Earth’s atmosphere. The temporal variation of these waves is studied using a record long 10-day continuous Rayleigh–Mie–Raman lidar sounding at midlatitudes. This data set shows a large variability of these waves on timescales of a few days and therefore provides new insights into wave intermittency phenomena, which can help to improve model simulations. Read more
Developing fragility functions for aquaculture rafts and eelgrass in the case of the 2011 Great East Japan tsunami Natural Hazards and Earth System Sciences DOI 10.5194/nhess-18-145-2018 10 January 2018 We developed fragility functions of aquaculture rafts and eelgrass based on damage data and numerical simulation of the 2011 Great East Japan tsunami. These fragility functions explain damage characteristics of both items against tsunami flow velocity. By understanding these characteristics, damage estimation and loss assessment as well as marine/fishery disaster mitigation plan and management in other areas of the world from future tsunamis can be implemented. Read more
New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium Annales Geophysicae DOI 10.5194/angeo-36-13-2018 9 January 2018 The question of whether mesospheric rotational population distributions of vibrationally excited OH are in equilibrium with the local kinetic temperature has been debated over several decades. We examine the relationship of multi-quantum relaxation pathways with the behavior exhibited by OH(v) rotational population distributions and find that the effective rotational temperatures of mesospheric OH(v) deviate from local thermodynamic equilibrium for all observed vibrational levels. Read more
Invited perspectives: Hydrological perspectives on precipitation intensity-duration thresholds for landslide initiation: proposing hydro-meteorological thresholds Natural Hazards and Earth System Sciences DOI 10.5194/nhess-18-31-2018 4 January 2018 The vast majority of shallow landslides and debris flows are precipitation initiated and predicted using historical landslides plotted versus observed precipitation information. However, this approach has severe limitations. This is partly due to the fact that it is not precipitation that initiates a landslide or debris flow but rather the hydrological dynamics in the soil and slope. We propose to include hydrological information in the regional hydro-meteorological hazard assessment. Read more
The UKC2 regional coupled environmental prediction system Geoscientific Model Development DOI 10.5194/gmd-11-1-2018 3 January 2018 In the real world the atmosphere, oceans and land surface are closely interconnected, and yet prediction systems tend to treat them in isolation. Those feedbacks are often illustrated in natural hazards, such as when strong winds lead to large waves and coastal damage, or when prolonged rainfall leads to saturated ground and high flowing rivers. For the first time, we have attempted to represent some of the feedbacks between sky, sea and land within a high-resolution forecast system for the UK. Read more
Synergy between land use and climate change increases future fire risk in Amazon forests Earth System Dynamics DOI 10.5194/esd-8-1237-2017 20 December 2017 Fires damage large areas of eastern Amazon forests when ignitions from human activity coincide with droughts, while more humid central and western regions are less affected. Here, we use a fire model to estimate that fire activity could increase by an order of magnitude without climate mitigation. Our results show that avoiding further agricultural expansion can limit fire ignitions but that tackling climate change is essential to insulate the interior Amazon through the 21st century. Read more
The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution Geoscientific Model Development DOI 10.5194/gmd-10-4577-2017 18 December 2017 Rivers control the movement of sediment and nutrients across Earth’s surface. Understanding how rivers change through time is important for mitigating natural hazards and predicting Earth’s response to climate change. We develop a new computer model for predicting how rivers cut through sediment and rock. Our model is designed to be joined with models of flooding, landslides, vegetation change, and other factors to provide a comprehensive toolbox for predicting changes to the landscape. Read more