A multilayer physically based snowpack model simulating direct and indirect radiative impacts of light-absorbing impurities in snow The Cryosphere DOI 10.5194/tc-11-2633-2017 20 November 2017 Light-absorbing impurities deposited on snow, such as soot or dust, strongly modify its evolution. We implemented impurity deposition and evolution in a detailed snowpack model, thereby expanding the reach of such models into addressing the subtle interplays between snow physics and impurities’ optical properties. Model results were evaluated based on innovative field observations at an Alpine site. This allows future investigations in the fields of climate, hydrology and avalanche prediction. Read more
A new diagnostic for tropospheric ozone production Atmospheric Chemistry and Physics DOI 10.5194/acp-17-13669-2017 17 November 2017 Understanding tropospheric ozone chemistry has been at the centre of the field of atmospheric chemistry for the last 30 years. However, our conceptual approach to diagnosing ozone production in global models has not advanced in this time. Our work presents a new and powerful approach for diagnosing tropospheric ozone production, providing a significant enhancement in our ability to understand the processes controlling ozone and how we can validate our assessment of these processes. Read more
Reviews and syntheses: on the roles trees play in building and plumbing the critical zone Biogeosciences DOI 10.5194/bg-14-5115-2017 17 November 2017 This review represents the outcome from an invigorating workshop discussion that involved tree physiologists, geomorphologists, ecologists, geochemists, and hydrologists and developed nine hypotheses that could be tested. We argue these hypotheses point to the essence of issues we must explore if we are to understand how the natural system of the earth surface evolves, and how humans will affect its evolution. This paper will create discussion and interest both before and after publication. Read more
Basin-scale heterogeneity in Antarctic precipitation and its impact on surface mass variability The Cryosphere DOI 10.5194/tc-11-2595-2017 15 November 2017 In this CESM modeling study, we uncover regional relationships in snowfall across Antarctica that are corroborated by regional modeling and ice core records. These relationships are driven by variability in large-scale atmospheric moisture transport and dampen overall Antarctic snowfall variability, with implications for Antarctic-sourced sea level variability and detection of an emergent anthropogenic signal in Antarctic mass trends. Read more
Regional Antarctic snow accumulation over the past 1000 years Climate of the Past DOI 10.5194/cp-13-1491-2017 10 November 2017 Regional Antarctic snow accumulation derived from 79 ice core records is evaluated as part of the PAGES Antarctica 2k working group. Our results show that surface mass balance for the total Antarctic ice sheet has increased at a rate of 7 ± 0.13 Gt dec-1 since 1800 AD, representing a net reduction in sea level of ~ 0.02 mm dec-1 since 1800 and ~ 0.04 mm dec-1 since 1900 AD. The largest contribution is from the Antarctic Peninsula. Read more
Towards representing human behavior and decision making in Earth system models – an overview of techniques and approaches Earth System Dynamics DOI 10.5194/esd-8-977-2017 8 November 2017 Today, human interactions with the Earth system lead to complex feedbacks between social and ecological dynamics. Modeling such feedbacks explicitly in Earth system models (ESMs) requires making assumptions about individual decision making and behavior, social interaction, and their aggregation. In this overview paper, we compare different modeling approaches and techniques and highlight important consequences of modeling assumptions. We illustrate them with examples from land-use modeling. Read more
Making better sense of the mosaic of environmental measurement networks: a system-of-systems approach and quantitative assessment Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-6-453-2017 6 November 2017 The term system-of-systems with respect to observational capabilities is frequently used, but what does it mean and how can it be assessed? Here, we define one possible interpretation of a system-of-systems architecture that is based upon demonstrable aspects of observing capabilities. We develop a set of assessment strands and then apply these to a set of atmospheric observational networks to decide which observations may be suitable for characterising satellite platforms in future work. Read more
Methanesulfonic acid (MSA) migration in polar ice: data synthesis and theory The Cryosphere DOI 10.5194/tc-11-2439-2017 3 November 2017 We combine a synthesis of 22 ice core records and a model of soluble impurity transport to investigate the enigmatic, post-depositional migration of methanesulfonic acid in polar ice. Our findings suggest that migration may be universal across coastal regions of Greenland and Antarctica, though it is mitigated at sites with higher accumulation and (or) lower impurity content. Records exhibiting severe migration may still be useful for inferring decadal and lower-frequency climate variability. MSA) migration in polar ice: data synthesis and theory">Read more
Global consequences of afforestation and bioenergy cultivation on ecosystem service indicators Biogeosciences DOI 10.5194/bg-14-4829-2017 3 November 2017 Many climate change mitigation scenarios require negative emissions from land management. However, environmental side effects are often not considered. Here, we use projections of future land use from two land-use models as input to a vegetation model. We show that carbon removal via bioenergy production or forest maintenance and expansion affect a range of ecosystem functions. Largest impacts are found for crop production, nitrogen losses, and emissions of biogenic volatile organic compounds. Read more
Is there 1.5-million-year-old ice near Dome C, Antarctica? The Cryosphere DOI 10.5194/tc-11-2427-2017 2 November 2017 The oldest dated deep ice core drilled in Antarctica has been retrieved at EPICA Dome C (EDC), reaching ~ 800 000 years. Obtaining an older palaeoclimatic record from Antarctica is one of the greatest challenges of the ice core community. Here, we estimate the age of basal ice in the Dome C area. We find that old ice (> 1.5 Myr) likely exists in two regions a few tens of kilometres away from EDC:Little Dome C PatchandNorth Patch. Read more