Soil properties and pre-Columbian settlement patterns in the Monumental Mounds Region of the Llanos de Moxos, Bolivian Amazon SOIL DOI 10.5194/soil-1-65-2015 6 January 2015 In the present paper we explore to what degree soil properties might have influenced pre-Columbian settlement patterns in the Monumental Mounds Region (MMR) of the Llanos de Moxos (LM), Bolivian Amazon. This study provides new data on the soil properties of the south-eastern Bolivian Amazon and reinforces the hypothesis that environmental constraints and opportunities exerted an important role on pre-Columbian occupation patterns and the population density reached in the Bolivian Amazon. Read more
What causes cooling water temperature gradients in a forested stream reach? Hydrology and Earth System Sciences DOI 10.5194/hess-18-5361-2014 20 December 2014 This study demonstrates the processes by which instantaneous longitudinal water temperature gradients may be generated in a stream reach that transitions from moorland to semi-natural forest in the absence of substantial groundwater inflows. Water did not cool as it flowed downstream. Instead, temperature gradients were generated by a combination of reduced rates of heating in the forested reach and advection of cooler (overnight and early morning) water from the upstream moorland catchment. Read more
Processes determining the marine alkalinity and calcium carbonate saturation state distributions Biogeosciences DOI 10.5194/bg-11-7349-2014 19 December 2014 We examine and discuss the portion of ocean alkalinity that varies in response to carbonate cycling and riverine alkalinity inputs using a new tracer, Alk*. We use this tracer to quantify the controls on marine carbonate saturation: At depth, we find carbonate cycling to be a minor control relative to organic matter cycling and pressure changes. In well-equilibrated surface water, we find carbonate cycling to be less important than temperature changes and freshwater cycling. Read more
Dams on Mekong tributaries as significant contributors of hydrological alterations to the Tonle Sap Floodplain in Cambodia Hydrology and Earth System Sciences DOI 10.5194/hess-18-5303-2014 18 December 2014 Hydrological modeling and assessment tools were used to provide evidence of the expected hydrological alterations that hydropower development in the lower Mekong tributaries could bring to the Tonle Sap. The most significant alterations are in terms of water levels during the dry season and rates of water level rise/drop which are crucial for tree seed germination and fish migrations, and therefore major ecological disruptions are likely to follow. Read more
Estimating the volume of glaciers in the Himalayan–Karakoram region using different methods The Cryosphere DOI 10.5194/tc-8-2313-2014 12 December 2014 Existing methods (area-volume relations, a slope-dependent volume estimation method, and two ice-thickness distribution models) are used to estimate the ice reserves stored in Himalayan-Karakoram glaciers. Resulting volumes range from 2955–4737 km³. Results from the ice-thickness distribution models agree well with local measurements; volume estimates from area-related relations exceed the estimates from the other approaches. Evidence on the effect of the selected method on results is provided. Read more
A virtual water network of the Roman world Hydrology and Earth System Sciences DOI 10.5194/hess-18-5025-2014 11 December 2014 Our virtual water network of the Roman World shows that virtual water trade and irrigation provided the Romans with resilience to interannual climate variability. Virtual water trade enabled the Romans to meet food demands from regions with a surplus. Irrigation provided stable water supplies for agriculture, particularly in large river catchments. However, virtual water trade also stimulated urbanization and population growth, which eroded Roman resilience to climate variability over time. Read more
Solar irradiances measured using SPN1 radiometers: uncertainties and clues for development Atmospheric Measurement Techniques DOI 10.5194/amt-7-4267-2014 8 December 2014 This work presents a comprehensive study of SPN1 radiometers accuracy and sources of uncertainty, drawing on laboratory experiments, numerical modelling and comparison studies between measurements from this sensor and state-of-the art instruments for six diverse sites. Several clues are provided for improving the SPN1 accuracy and agreement with state-of-the art measurements. Read more
A possible influence of the Great White Spot on Saturn kilometric radiation periodicity Annales Geophysicae DOI 10.5194/angeo-32-1463-2014 4 December 2014 In this paper we show that the large thunderstorm called Great White Spot, which raged for about 9 months in Saturn’s troposphere in 2010/2011, was accompanied by changes in the periodicity and phasing of auroral radio emissions. We suggest that the thunderstorm was a source of intense gravity waves causing a global change in Saturn’s ionospheric winds via energy and momentum deposition. This supports the theory that Saturn’s magnetospheric periodicities are driven by the upper atmosphere. Read more
Estimating degree-day factors from MODIS for snowmelt runoff modeling Hydrology and Earth System Sciences DOI 10.5194/hess-18-4773-2014 3 December 2014 In this paper, we propose a new method for estimating the snowmelt degree-day factor (DDFS) directly from MODIS snow covered area and ground-based snow depth data without calibration. Snow density is estimated as the ratio between observed precipitation and changes in the snow volume for days with snow accumulation. DDFS values are estimated as the ratio between changes in the snow water equivalent and difference between the daily temperature and a threshold value for days with snowmelt. Read more
Potential climate forcing of land use and land cover change Atmospheric Chemistry and Physics DOI 10.5194/acp-14-12701-2014 3 December 2014 While climate change mitigation policy often focuses on the energy sector, we find that 40% of the historical human-caused change in the Earth’s radiative balance can be attributed to land use activities, such as deforestation and agriculture. Since pressure on land resources is expected to increase, we compute a theoretical upper bound on the radiative balance impacts from future land use which suggests that not only energy policy but land policy is necessary to minimize future climate change. Read more
Estimated stocks of circumpolar permafrost carbon with quantified uncertainty ranges and identified data gaps Biogeosciences DOI 10.5194/bg-11-6573-2014 1 December 2014 This study provides an updated estimate of organic carbon stored in the northern permafrost region. The study includes estimates for carbon in soils (0 to 3 m depth) and deeper sediments in river deltas and the Yedoma region. We find that field-data is still scarce from many regions. Total estimated carbon storage is ~1300 Pg with an uncertainty range of between 1100 to 1500 Pg. Around 800 Pg carbon is perennially frozen, equivalent to all carbon dioxide currently in the Earths atmosphere. Read more
A comparison between VEGA 1, 2 and Giotto flybys of comet 1P/Halley: implications for Rosetta Annales Geophysicae DOI 10.5194/angeo-32-1441-2014 28 November 2014 We discuss three flybys (within a time span of 8 days) of comet 1P/Halley by VEGA 1, 2 and Giotto. Looking at two different plasma phenomena: mirror mode waves and field line draping; we study the differences in SW-comet interaction between these three flybys. We find that on this time scale (comparable to Rosetta’s orbits) there is a significant difference, both caused by changing outgassing rate of the comet and changes in the solar wind. We discuss implications for Rosetta RPC observations. Read more
Correlations between climate network and relief data Nonlinear Processes in Geophysics DOI 10.5194/npg-21-1127-2014 27 November 2014 In the past few years, complex networks have been extensively applied to climate sciences, yielding the new field of climate networks. Here, we generalize climate network analysis by investigating the influence of altitudes in network topology. More precisely, we verified that nodes group into different communities corresponding to geographical areas with similar relief properties. This new approach may contribute to obtaining more complete climate network models. Read more
Path independence of climate and carbon cycle response over a broad range of cumulative carbon emissions Earth System Dynamics DOI 10.5194/esd-5-409-2014 24 November 2014 Recent studies have identified an approximately proportional relationship between global warming and cumulative carbon emissions. This relationship – referred to as the transient climate response to cumulative carbon emissions (TCRE) – is useful for climate policy applications. We show that the TCRE is constant for cumulative emissions lower than ~1500 GtC, but declines for higher cumulative emissions. We also find the TCRE to decrease with increasing emission rate. Read more
Long-term trends at the Boknis Eck time series station (Baltic Sea), 1957–2013: does climate change counteract the decline in eutrophication? Biogeosciences DOI 10.5194/bg-11-6323-2014 24 November 2014 A time series of 9 oceanic parameters from the coastal time series station Boknis Eck (BE, South Western Baltic Sea) in the period of 1957-2013 is analysed with respect to seasonal cycles and longterm trends. Most striking was a paradoxical decreasing trend in oxygen with a simultaneous decline in eutrophication. Possible reasons for this paradox, e.g. processes related to warming temperatures such as increased decomposition of organic matter or altered ventilation, are discussed. Read more
Detailed ice loss pattern in the northern Antarctic Peninsula: widespread decline driven by ice front retreats The Cryosphere DOI 10.5194/tc-8-2135-2014 24 November 2014 This study of one of the most rapidly changing glacier regions on Earth – the Antarctic Peninsula – uses two types of satellite data to measure the rates of ice loss in detail for the individual glaciers. The satellite data is laser altimetry from ICESat and stereo image DEM differences. The results show that 24..9 ± 7.8 billion tons of ice are lost from the region north of 66°S on the Peninsula each year. The majority of the data cover 2003-2008. Read more
The global monsoon across timescales: coherent variability of regional monsoons Climate of the Past DOI 10.5194/cp-10-2007-2014 21 November 2014 It remains a debated issue as to what extent and at which timescales the global monsoon can be viewed as a major mode of climate variability. For this purpose, a PAGES (Past Global Changes) working group (WG) was set up to investigate the concept of the global monsoon and its future research directions. The WG’s synthesis is presented here. Read more
Complex networks for streamflow dynamics Hydrology and Earth System Sciences DOI 10.5194/hess-18-4565-2014 20 November 2014 This study introduces the theory of networks, and in particular complex networks, to examine connections in streamflow dynamics. Monthly streamflow data from a network of 639 stations in the United States are studied. The connections are examined primarily using the concept of clustering coefficient, which quantifies the network’s tendency to cluster. The clustering coefficient analysis is performed with several different threshold levels based on correlations in streamflow between the stations. Read more
Missing SO2 oxidant in the coastal atmosphere? – observations from high-resolution measurements of OH and atmospheric sulfur compounds Atmospheric Chemistry and Physics DOI 10.5194/acp-14-12209-2014 20 November 2014 Sulfuric acid plays a major role in the formation of aerosol particles and clouds. Measurements at the west coast of Ireland reveal that oxidation of SO2 by OH explains only 20%, on average, of H2SO4 formation in coastal marine air. Additional sources may be oxidation by Criegee intermediates produced photolytically and/or formation from SO3 instead of SO2 in the oxidation of dimethyl sulfide suggesting an important role of marine emissions in the self-cleaning power of the atmosphere. Read more
Historical impact of water infrastructure on water levels of the Mekong River and the Tonle Sap system Hydrology and Earth System Sciences DOI 10.5194/hess-18-4529-2014 17 November 2014 This paper analyses the historical water levels of the Mekong River and Tonle Sap system by comparing pre- and post-1991 daily observations from six stations along the Mekong mainstream from Chiang Saen (northern Thailand), to Stung Treng (Cambodia), and the Prek Kdam station on the Tonle Sap River. Read more
Changes in extreme regional sea surface height due to an abrupt weakening of the Atlantic meridional overturning circulation Ocean Science DOI 10.5194/os-10-881-2014 7 November 2014 As an extreme scenario of dynamical sea level changes, regional sea surface height (SSH) changes that occur in the North Atlantic due to an abrupt weakening of the Atlantic meridional overturning circulation (AMOC) are simulated. Two versions of the same ocean-only model are used to study the effect of ocean model resolution on these SSH changes. Read more
Gas emissions at the continental margin west of Svalbard: mapping, sampling, and quantification Biogeosciences DOI 10.5194/bg-11-6029-2014 6 November 2014 The authors mapped, sampled, and quantified gas emissions at the continental margin west of Svalbard in late summer 2012. They found that gas emissions occurred widespread between about 80 and 415 m water depth, which indicates that hydrate dissolution might only be one of several triggers for active hydrocarbon seepage in that area. Read more
Determining the focal mechanisms of the events in the Carpathian region of Ukraine Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-3-229-2014 30 October 2014 The paper is devoted to mathematical modelling of propagation of seismic waves in inhomogeneous media. The trial and error method for determining the angles of orientation of fault plane and earthquake mechanism has been proposed. The graphic and trial and error approaches have been applied for determining the source parameters of earthquakes in seismically active region of Eastern Carpathian. Read more
Analytical approach for predicting fresh water discharge in an estuary based on tidal water level observations Hydrology and Earth System Sciences DOI 10.5194/hess-18-4153-2014 17 October 2014 In this study, the authors investigate the influence of river discharge on tidal wave propagation in the Yangtze estuary with specific attention to residual water level slope. Read more
An autonomous adaptive low-power instrument platform (AAL-PIP) for remote high-latitude geospace data collection Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-3-211-2014 10 October 2014 This paper presents the development considerations and design for ground-based instrumentation that is being deployed on the East Antarctic Plateau along a 40° magnetic meridian chain to investigate interhemispheric magnetically conjugate geomagnetic coupling and other space-weather-related phenomena. Read more
Mapping the physico-chemical properties of mineral dust in western Africa: mineralogical composition Atmospheric Chemistry and Physics DOI 10.5194/acp-14-10663-2014 10 October 2014 In the last few years, several ground-based and airborne field campaigns have allowed the exploration of the properties and impacts of mineral dust in western Africa. This paper explores the synthesis of these observations to provide a large-scale quantitative view of the mineralogical composition and its variability according to source region and time after transport. Read more
Constraining CO2 emissions from open biomass burning by satellite observations of co-emitted species: a method and its application to wildfires in Siberia Atmospheric Chemistry and Physics DOI 10.5194/acp-14-10383-2014 1 October 2014 A method to constrain carbon dioxide (CO2) emissions from open biomass burning by using satellite observations of co-emitted species and a chemistry-transport model (CTM) is proposed and applied to the case of wildfires in Siberia. Read more
The origin of noise and magnetic hysteresis in crystalline permalloy ring-core fluxgate sensors Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-3-201-2014 29 September 2014 In certain polycrystalline permalloy fluxgate sensors, a single phenomenon may cause both fluxgate noise and magnetic hysteresis; explain Barkhausen jumps, remanence and coercivity; and avoid domain denucleation. This phenomenon, domain wall reconnection, is presented as part of a theoretical model. Read more
The effect of changing sea ice on the physical vulnerability of Arctic coasts The Cryosphere DOI 10.5194/tc-8-1777-2014 26 September 2014 Sea ice provides a first-order control on the physical vulnerability of Arctic coasts to erosion, inundation, and damage to settlements and infrastructures by ocean water. This paper focuses on how the changing sea-ice cover has influenced coastal erosion over the satellite record. Read more
A framework for benchmarking of homogenisation algorithm performance on the global scale Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-3-187-2014 25 September 2014 The International Surface Temperature Initiative (ISTI) is striving towards substantively improving our ability to robustly understand historical land surface air temperature change at all scales. A key recently completed first step has been collating all available records into a comprehensive open access, traceable and version-controlled databank. Read more
The XWS open access catalogue of extreme European windstorms from 1979 to 2012 Natural Hazards and Earth System Sciences DOI 10.5194/nhess-14-2487-2014 22 September 2014 This papers introduces the XWS (eXtreme WindStorms) catalogue, which consists of storm tracks and model-generated maximum 3 s wind-gust footprints for 50 of the most extreme winter windstorms to hit Europe in the period 1979–2012. Read more
The length of the world’s glaciers – a new approach for the global calculation of center lines The Cryosphere DOI 10.5194/tc-8-1741-2014 19 September 2014 Here the authors present a first global assessment of glacier length using an automated method that relies on glacier surface slope, distance to the glacier margins and a set of trade-off functions. Read more
Smoothing error pitfalls Atmospheric Measurement Techniques DOI 10.5194/amt-7-3023-2014 18 September 2014 The difference due to the content of a priori information between a constrained retrieval and the true atmospheric state is usually represented by a diagnostic quantity called smoothing error. In this paper it is shown that the concept of the smoothing error as a component of the retrieval error budget is questionable because it is not compliant with Gaussian error propagation. Read more
Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years The Cryosphere DOI 10.5194/tc-8-1699-2014 17 September 2014 The authors employ a 3D, higher-order model to simulate the evolution of Pine Island Glacier over the next 50 yr in response to changes in its surface mass balance, the position of its calving front and ocean-induced ice shelf melting. Read more
Tropospheric ozone increases over the southern Africa region: bellwether for rapid growth in Southern Hemisphere pollution? Atmospheric Chemistry and Physics DOI 10.5194/acp-14-9855-2014 17 September 2014 Increases in tropospheric ozone based on ozonesonde records (early 1990s to 2008) over subtropical stations in Irene (South Africa) and Réunion have been reported. Over Irene a large increase in the urban-influenced boundary layer (BL) was also observed. This paper shows that the Irene BL trend is at least partly due to a gradual change in the sonde launch times. Read more
Numerical studies on the Impact of the Last Glacial Cycle on recent borehole temperature profiles: implications for terrestrial energy balance Climate of the Past DOI 10.5194/cp-10-1693-2014 10 September 2014 In this paper, the authors provide the first estimate of the impact of the development of the Laurentide ice sheet on the estimates of energy and temperature reconstructions from measurements of terrestrial borehole temperatures in North America. Read more
Short ensembles: an efficient method for discerning climate-relevant sensitivities in atmospheric general circulation models Geoscientific Model Development DOI 10.5194/gmd-7-1961-2014 8 September 2014 This paper explores the feasibility of an experimentation strategy for investigating sensitivities in fast components of atmospheric general circulation models. Read more
Release of hydrogen peroxide and antioxidants by the coral Stylophora pistillata to its external milieu Biogeosciences DOI 10.5194/bg-11-4587-2014 1 September 2014 This paper presents a laboratory characterisation of hydrogen peroxide (H2O2) and antioxidant activity release kinetics by intact, non-stressed Stylophora pistillata. Experimenting with bleached and non-bleached corals and different stirring speeds, the authors explored the sources and modes of H2O2 and antioxidant release. Read more
Protection against lightning at a geomagnetic observatory Geoscientific Instrumentation, Methods and Data Systems DOI 10.5194/gi-3-135-2014 27 August 2014 The Sinji Vrh Geomagnetic Observatory, built on the brow of Gora, the mountain above Ajdovščina in Slovenia, is very often struck by lightning. This manuscript analyses the formation of lightning in the area and ways of protecting the observatory. Read more
Molecular corridors and kinetic regimes in the multiphase chemical evolution of secondary organic aerosol Atmospheric Chemistry and Physics DOI 10.5194/acp-14-8323-2014 20 August 2014 Based on molecular identification of secondary organic aerosol (SOA) oxidation products, the authors show here that the chemical evolution of SOA from a variety of volatile organic compound precursors adheres to characteristic “molecular corridors” with a tight inverse correlation between volatility and molar mass. Read more
Elevation and elevation change of Greenland and Antarctica derived from CryoSat-2 The Cryosphere DOI 10.5194/tc-8-1539-2014 20 August 2014 This study focuses on the present-day surface elevation of the Greenland and Antarctic ice sheets. Based on 3 years of CryoSat-2 data acquisition the authors derived new elevation models (DEMs) as well as elevation change maps and volume change estimates for both ice sheets. Read more
Diverse coral communities in mangrove habitats suggest a novel refuge from climate change Biogeosciences DOI 10.5194/bg-11-4321-2014 19 August 2014 This paper characterises the first natural, non-reef coral refuge from thermal stress and ocean acidification and identifies resiliency factors for mangrove–coral habitats. Read more
MOMBA 1.1 – a high-resolution Baltic Sea configuration of GFDL’s Modular Ocean Model Geoscientific Model Development DOI 10.5194/gmd-7-1713-2014 18 August 2014 We present a new coupled ocean-circulation–ice model configuration of the Baltic Sea. The model features, contrary to most existing configurations, a high horizontal resolution of 1 nautical mile (1.85 km), which is eddy-resolving over much of the domain. Read more
Projecting Antarctic ice discharge using response functions from SeaRISE ice-sheet models Earth System Dynamics DOI 10.5194/esd-5-271-2014 14 August 2014 In this paper, the authors attempt to estimate the uncertainty range of future ice discharge from Antarctica by combining uncertainty in the climatic forcing, the oceanic response and the ice-sheet model response. Read more
Quantification of ice nuclei active at near 0 °C temperatures in low-altitude clouds at the Puy de Dôme atmospheric station Atmospheric Chemistry and Physics DOI 10.5194/acp-14-8185-2014 14 August 2014 In this study, cloud water was collected aseptically from the summit of Puy de Dôme (1465 m a.s.l., France) within contrasted meteorological and physico-chemical situations. Total and biological (i.e. heat-sensitive) IN were quantified by droplet-freezing assay between −5 °C and −14 °C. Read more
Weighing the ocean with bottom-pressure sensors: robustness of the ocean mass annual cycle estimate Ocean Science DOI 10.5194/os-10-701-2014 11 August 2014 We use ocean bottom-pressure measurements from 17 tropical sites to determine the annual cycle of ocean mass. We show that such a calculation is robust, and use three methods to estimate errors in the mass determination. Read more
Ice–ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers The Cryosphere DOI 10.5194/tc-8-1457-2014 8 August 2014 This paper presents a suite of fjord salinity, temperature, turbidity versus depth casts along with glacial runoff estimation from Rink and Store glaciers, two major marine outlets draining the western sector of the GrIS during 2009 and 2010. Read more
EARLINET: towards an advanced sustainable European aerosol lidar network Atmospheric Measurement Techniques DOI 10.5194/amt-7-2389-2014 8 August 2014 This paper gives an overview of the European Aerosol Research Lidar Network (EARLINET) main developments since 2000 and introduces the dedicated EARLINET special issue, which reports on the technical solutions and scientific results related to the use of advanced lidar remote sensing techniques for the study of aerosol properties. Read more
Integrated assessment of global water scarcity over the 21st century under multiple climate change mitigation policies Hydrology and Earth System Sciences DOI 10.5194/hess-18-2859-2014 6 August 2014 Water scarcity conditions over the 21st century both globally and regionally are assessed in the context of climate change and climate mitigation policies, by estimating both water availability and water demand within the Global Change Assessment Model, a leading community-integrated assessment model of energy, agriculture, climate, and water. Read more
Impact of a 30% reduction in Atlantic meridional overturning during 2009–2010 Ocean Science DOI 10.5194/os-10-683-2014 6 August 2014 The Atlantic meridional overturning circulation comprises warm upper waters flowing northward, becoming colder and denser until they form deep water in the Labrador and Nordic Seas that then returns southward through the North and South Atlantic. We have been monitoring the circulation at 25° N since 2004 and report on the results here. Read more