Impact of climate and land cover changes on tropospheric ozone air quality and public health in East Asia between 1980 and 2010 Atmospheric Chemistry and Physics DOI 10.5194/acp-15-10093-2015 9 September 2015 Historical land cover and land use change alone between 1980 and 2010 could lead to reduced summertime surface ozone by up to 4ppbv in East Asia. Climate change alone could lead to an increase in summertime ozone by 2-10ppbv in most of East Asia. Land cover change could offset part of the climate effect and lead to a previously unknown public health benefit. The sensitivity of surface ozone to land cover change is more dependent on dry deposition than isoprene emission in most of East Asia. Read more
The feasibility of water vapor sounding of the cloudy boundary layer using a differential absorption radar technique Atmospheric Measurement Techniques DOI 10.5194/amt-8-3631-2015 8 September 2015 This paper describes the feasibility of using a differential absorption radar technique for the remote sensing of water vapor within clouds near the Earth surface from a spaceborne platform. The proposed methodology is shown to be theoretically achievable and complimentary to existing water vapor remote sensing methods. Read more
Past changes in the vertical distribution of ozone – Part 3: Analysis and interpretation of trends Atmospheric Chemistry and Physics DOI 10.5194/acp-15-9965-2015 7 September 2015 Trends in the vertical distribution of ozone are reported for new and recently revised data sets. The amount of ozone-depleting compounds in the stratosphere peaked in the second half of the 1990s. We examine the trends before and after that peak to see if any change in trend is discernible. The previously reported decreases are confirmed. Furthermore, the downward trend in upper stratospheric ozone has not continued. The possible significance of any increase is discussed in detail. Read more
Diesel-related hydrocarbons can dominate gas phase reactive carbon in megacities Atmospheric Chemistry and Physics DOI 10.5194/acp-15-9983-2015 7 September 2015 Technological shifts between fuel sources have had unexpected impacts on atmospheric composition and these significant changes can go undetected if source-specific monitoring infrastructure is not in place. We present chemically comprehensive, continuous measurements of organic compounds in a developed megacity (London), that show diesel-related hydrocarbons can dominate reactive carbon and ozone formation potential, highlighting a serious underestimation of this source in emission inventories. Read more
Retrieving the paleoclimatic signal from the deeper part of the EPICA Dome C ice core The Cryosphere DOI 10.5194/tc-9-1633-2015 20 August 2015 The oldest paleoclimatic information is buried within the lowermost layers of deep ice cores. It is therefore essential to judge how deep these records remain unaltered. We study the bottom 60 meters of the EPICA Dome C ice core from central Antarctica to show that the paleoclimatic signal is only affected at the small scale (decimeters) in terms of some of the global ice properties. However our data suggest that the time scale has been considerably distorted by mechanical stretching. Read more
Observation of a new type of low-frequency waves at comet 67P/Churyumov-Gerasimenko Annales Geophysicae DOI 10.5194/angeo-33-1031-2015 19 August 2015 We present a first report on magnetic field measurements made in the coma of comet 67P/C-G in its low activity state. The plasma environment is dominated by quasi-coherent, large-amplitude, compressional magnetic field oscillations around 40 mHz, differing from the observations at strongly active comets where waves at the cometary ion gyro-frequencies are the main feature. We propose a cross-field current instability associated with the newborn cometary ions as a possible source mechanism. Read more
Century-scale simulations of the response of the West Antarctic Ice Sheet to a warming climate The Cryosphere DOI 10.5194/tc-9-1579-2015 18 August 2015 We used a high resolution ice sheet model capable of resolving grouding line dynamics (BISICLES) to compute responses of the major West Antarctic ice streams to projections of ocean and atmospheric warming. This is computationally demanding, and although other groups have considered parts of West Antarctica, we think this is the first calculation for the whole region at the sub-kilometer resolution that we show is required. Read more
Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer Atmospheric Chemistry and Physics DOI 10.5194/acp-15-8889-2015 13 August 2015 Ozone holds a certain fascination in atmospheric science. It is ubiquitous in the atmosphere, central to tropospheric oxidation chemistry, and yet harmful to human and ecosystem health as well as being an important greenhouse gas. It is not emitted into the atmosphere but is a byproduct of the very oxidation chemistry it largely initiates. This review examines current understanding of the processes regulating tropospheric ozone at global to local scales from both measurements and models. Read more
Impact of model developments on present and future simulations of permafrost in a global land-surface model The Cryosphere DOI 10.5194/tc-9-1505-2015 7 August 2015 In this paper we use a global land-surface model to study the dynamics of Arctic permafrost. We examine the impact of new and improved processes in the model, namely soil depth and resolution, organic soils, moss and the representation of snow. These improvements make the simulated soil temperatures and thaw depth significantly more realistic. Simulations under future climate scenarios show that permafrost thaws more slowly in the new model version, but still a large amount is lost by 2100. Read more
Mapping snow depth from manned aircraft on landscape scales at centimeter resolution using structure-from-motion photogrammetry The Cryosphere DOI 10.5194/tc-9-1445-2015 5 August 2015 This paper presents a photogrammetric method for measuring topography from manned aircraft with an accuracy of 30 cm and repeatability of 8 cm, at significantly lower cost than other methods. Here we created difference maps to demonstrate that we could measure snow depth with an accuracy of 10 cm compared to over 6000 snow-probe measurements on the ground, but do so over entire watersheds at 10-20 cm spatial resolution rather than just a few transects. Read more
