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Weathering by tree-root-associating fungi diminishes under simulated Cenozoic atmospheric CO₂decline

We report experimental evidence for a negative feedback across a declining Cenozoic [CO₂]_a range from 1500 to 200 ppm, whereby low [CO₂]_a curtails mineral surface alteration via trenching and etch pitting by arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) fungal partners of tree roots.

Ensemble projections of future streamflow droughts in Europe

This paper addresses the issue of future developments in streamflow drought characteristics across Europe.

Seabed topography beneath Larsen C Ice Shelf from seismic soundings

The Cryosphere
DOI 10.5194/tc-8-1-2014
2 January 2014

Seismic reflection soundings of ice thickness and seabed depth were acquired on the Larsen C Ice Shelf in order to test a sub-ice shelf bathymetry model derived from the inversion of IceBridge gravity data.

The surface temperatures of Earth: steps towards integrated understanding of variability and change

Geoscientific Instrumentation, Methods and Data Systems
DOI 10.5194/gi-2-305-2013
18 December 2013

In a community-based activity in June 2012, the EarthTemp Network brought together 55 researchers from five continents to improve the interaction between scientific communities who focus on surface temperature in particular domains, to exploit the strengths of different observing systems and to better meet the needs of different communities.

Quantifying mesoscale soil moisture with the cosmic-ray rover

This paper explores the challenges and opportunities for mapping soil moisture over large areas using the cosmic-ray rover.

Statistical analysis to characterize transport of nutrients in groundwater near an abandoned feedlot

Surface water from a lagoon and groundwater samples from 17 wells within and near an abandoned feedlot in northwestern Minnesota, USA, were analyzed for carbon, nutrients, and field parameters.

A simple explanation for the sensitivity of the hydrologic cycle to surface temperature and solar radiation and its implications for global climate change

The global hydrologic cycle is likely to increase in strength with global warming, although some studies indicate that warming due to solar absorption may result in a different sensitivity than warming due to an elevated greenhouse effect. Here we show that these sensitivities of the hydrologic cycle can be derived analytically from an extremely simple surface energy balance model that is constrained by the assumption that vertical convective exchange within the atmosphere operates at the thermodynamic limit of maximum power.

Seasonal variations of sea–air CO₂ fluxes in the largest tropical marginal sea (South China Sea) based on multiple-year underway measurements

Based upon 14 field surveys conducted between 2003 and 2008, this paper shows that the seasonal pattern of sea surface partial pressure of CO₂ (pCO₂) and sea–air CO₂ fluxes differed among four different physical–biogeochemical domains in the South China Sea proper.

Voyager 2 observation of the multifractal spectrum in the heliosphere and the heliosheath

This paper looks in detail at the multifractal scaling of the fluctuations in the interplanetary magnetic field strength as measured onboard Voyager 2 in the entire heliosphere and even in the heliosheath.

Rainfall estimation using moving cars as rain gauges – laboratory experiments

The spatial assessment of short time-step precipitation is a challenging task. Low density of observation networks, as well as the bias in radar rainfall estimation motivated the new idea of exploiting cars as moving rain gauges with windshield wipers or optical sensors as measurement devices.

Arctic stratospheric dehydration – Part 1: Unprecedented observation of vertical redistribution of water

This paper presents high-resolution measurements of water vapour, aerosols and clouds in the Arctic stratosphere in January and February 2010 carried out by in situ instrumentation on balloon sondes and high-altitude aircraft combined with satellite observations.

Quantifying aerosol mixing state with entropy and diversity measures

This paper presents the first quantitative metric for aerosol population mixing state, defined as the distribution of per-particle chemical species composition.

Paleosols in the Transantarctic Mountains: indicators of environmental change

Solid Earth
DOI 10.5194/se-4-451-2013
20 November 2013

Paleosols on unconsolidated deposits are emphasized in this study. Examples are given from the McMurdo Dry Valleys (78° S) and two outlet glaciers in the central and southern TAMS, including the Hatherton–Darwin Glacier region (80° S) and the Beardmore Glacier region (85°30’ S).

Inverse streamflow routing

Here we develop a methodology to invert the routing process, i.e., to derive the spatially distributed runoff from streamflow (e.g., measured at gauge stations) by inverting an arbitrary linear routing model using fixed interval smoothing.

Peak glacial ¹⁴C ventilation ages suggest major draw-down of carbon into the abyssal ocean

Here we present a new, though still fragmentary, ocean-wide Δ¹⁴C data set showing that during the Last Glacial Maximum (LGM) and Heinrich Stadial 1 (HS-1) the maximum ¹⁴C age difference between ocean deep waters and the atmosphere exceeded the modern values by up to 1500 ¹⁴C yr, in the extreme reaching 5100 ¹⁴C yr.

Heterogeneous formation of polar stratospheric clouds – Part 2: Nucleation of ice on synoptic scales

This paper provides compelling evidence for the importance of heterogeneous nucleation, likely on solid particles of meteoritic origin, and of small-scale temperature fluctuations, for the formation of ice particles in the Arctic stratosphere.

Where to find 1.5 million yr old ice for the IPICS “Oldest-Ice” ice core

The recovery of a 1.5 million yr long ice core from Antarctica represents a keystone of our understanding of Quaternary climate, the progression of glaciation over this time period and the role of greenhouse gas cycles in this progression. Here we tackle the question of where such ice may still be found in the Antarctic ice sheet

IPICS “Oldest-Ice” ice core">Read more

Ratios among atmospheric trace gases together with winds imply exploitable information for bird navigation: a model elucidating experimental results

A model of avian goal-oriented navigation is described that is based on two empirical findings building a bridge from ornithology to atmospheric chemistry.

A thermodynamic approach to link self-organization, preferential flow and rainfall–runoff behaviour

This study investigates whether a thermodynamically optimal hillslope structure can, if existent, serve as a first guess for uncalibrated predictions of rainfall–runoff.

Filamentary structure in chemical tracer distributions near the subtropical jet following a wave breaking event

This paper presents a set of observations and analyses of trace gas cross sections in the extratropical upper troposphere/lower stratosphere (UTLS).

Nitrous Oxide (N₂O) production in axenic Chlorella vulgaris microalgae cultures: evidence, putative pathways, and potential environmental impacts

Using antibiotic assays and genomic analysis, this study demonstrates nitrous oxide (N₂O) is generated from axenic Chlorella vulgaris cultures. In batch assays, this production is magnified under conditions favouring intracellular nitrite accumulation, but repressed when nitrate reductase (NR) activity is inhibited.

Global monitoring of terrestrial chlorophyll fluorescence from moderate-spectral-resolution near-infrared satellite measurements: methodology, simulations, and application to GOME-2

Here, we describe a new methodology to retrieve global far-red fluorescence information; we use hyperspectral data with a simplified radiative transfer model to disentangle the spectral signatures of three basic components: atmospheric absorption, surface reflectance, and fluorescence radiance. An empirically based principal component analysis approach is employed, primarily using cloudy data over ocean, to model and solve for the atmospheric absorption.

GOME-2">Read more

Cloud-resolving simulations of mercury scavenging and deposition in thunderstorms

This study examines dynamical and microphysical features of convective clouds that affect mercury (Hg) wet scavenging and concentrations in rainfall.

Carbonate mineral saturation states in the East China Sea: present conditions and future scenarios

To assess the impact of rising atmospheric CO₂ and eutrophication on the carbonate chemistry of the East China Sea shelf waters, saturation states (Ω) for two important biologically relevant carbonate minerals were calculated throughout the water column.

A novel salinity proxy based on Na incorporation into foraminiferal calcite

This study investigates the impact of salinity on foraminiferal Na/Ca values by laser ablation ICP-MS analyses of specimens of the benthic foraminifer Ammonia tepida cultured at a range of salinities (30.0–38.6).

Critical impacts of global warming on land ecosystems

Here we present a macro-scale analysis of climate change impacts on terrestrial ecosystems based on newly developed sets of climate scenarios featuring a step-wise sampling of global mean temperature increase between 1.5 and 5 K by 2100.

Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes

The purpose of this study is to use field-based and satellite remote-sensing-based methods to assess leaf nitrogen pools in five diverse European agricultural landscapes located in Denmark, Scotland (United Kingdom), Poland, the Netherlands and Italy.

LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes">Read more

Naphthalene SOA: redox activity and naphthoquinone gas–particle partitioning

Chamber secondary organic aerosol from low-NO_x photooxidation of naphthalene by hydroxyl radical was examined with respect to its redox cycling behaviour using the dithiothreitol assay.

SOA: redox activity and naphthoquinone gas–particle partitioning">Read more

Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models

Ocean ecosystems are increasingly stressed by human-induced changes of their physical, chemical and biological environment. Here, we use the most recent simulations performed in the framework of the Coupled Model Intercomparison Project 5 to assess how stressors such as warming, acidification deoxygenation and changes in primary productivity by marine phytoplankton, may evolve over the course of the 21st century.

Antarctic ice-mass balance 2003 to 2012: regional reanalysis of GRACE satellite gravimetry measurements with improved estimate of glacial-isostatic adjustment based on GPS uplift rates

The Cryosphere
DOI 10.5194/tc-7-1499-2013
25 September 2013

We present regional-scale mass balances for 25 drainage basins of the Antarctic Ice Sheet (AIS) from satellite observations of the Gravity and Climate Experiment (GRACE) for time period January 2003 to September 2012.

GRACE satellite gravimetry measurements with improved estimate of glacial-isostatic adjustment based on GPS uplift rates">Read more

The impact of nitrogen and phosphorous limitation on the estimated terrestrial carbon balance and warming of land use change over the last 156 yr

We examine the impact of land use and land cover change (LULCC) over the period from 1850 to 2005 using an Earth system model that incorporates nitrogen and phosphorous limitation on the terrestrial carbon cycle.

Stereoscopic determination of all-sky altitude map of aurora using two ground-based Nikon DSLR cameras

A new stereoscopic measurement technique is developed to obtain an all-sky altitude map of aurora using two ground-based digital single-lens reflex (DSLR) cameras.

DSLR cameras">Read more

Black carbon in the Arctic: the underestimated role of gas flaring and residential combustion emissions

Chemistry transport models and climate chemistry models struggle to reproduce the Arctic Haze phenomenon, and this has recently prompted changes in aerosol removal schemes to remedy the modeling problems. In this paper, we show that shortcomings in current emission data sets are at least as important.

The magnitude and causes of uncertainty in global model simulations of cloud condensation nuclei

Here we perform a variance-based analysis of a global 3-D aerosol microphysics model to quantify the magnitude and leading causes of parametric uncertainty in model-estimated present-day concentrations of cloud condensation nuclei.

Global CO₂ fluxes estimated from GOSAT retrievals of total column CO₂

This paper presents one of the first estimates of the global distribution of CO₂surface fluxes using total column CO₂ measurements retrieved by the SRON-KIT RemoTeC algorithm from the Greenhouse gases Observing SATellite (GOSAT).

GOSAT retrievals of total column CO₂">Read more

Gravitational separation in the stratosphere – a new indicator of atmospheric circulation

The O₂/N₂ ratio observed in the middle stratosphere, corrected for gravitational separation, showed the same mean air age as estimated from the CO₂ mole fraction. Therefore, gravitational separation is usable as a new indicator of changes in the atmospheric circulation in the stratosphere.

North–south palaeohydrological contrasts in the central Mediterranean during the Holocene: tentative synthesis and working hypotheses

On the basis of a multi-proxy approach and a strategy combining lacustrine and marine records along a north–south transect, data collected in the central Mediterranean within the framework of a collaborative project have led to reconstruction of high-resolution and well-dated palaeohydrological records and to assessment of their spatial and temporal coherency.

Climate response to imposed solar radiation reductions in high latitudes

The results of this paper suggest that, until emissions reductions are sufficient to limit the warming influence of increasing greenhouse gas concentrations, polar reductions in solar radiation, if they could be efficiently and effectively implemented, warrant further research as an approach to moderating the early stages of both high-latitude and global warming.

Consistent increase in Indian monsoon rainfall and its variability across CMIP-5 models

The possibility of an impact of global warming on the Indian monsoon is of critical importance for the large population of this region. Future projections within the Coupled Model Intercomparison Project Phase 3 (CMIP-3) showed a wide range of trends with varying magnitude and sign across models. Here the Indian summer monsoon rainfall is evaluated in 20 CMIP-5 models for the period 1850 to 2100.

CMIP-5 models">Read more

Quantitative evaluation of emission controls on primary and secondary organic aerosol sources during Beijing 2008 Olympics

To assess the primary and secondary sources of fine organic aerosols after the aggressive implementation of air pollution controls during the 2008 Beijing Olympic Games, 12 h PM_2.5 values were measured at an urban site at Peking University (PKU) and an upwind rural site at Yufa during the CAREBEIJING-2008 (Campaigns of Air quality REsearch in BEIJING and surrounding region) summer field campaign.

Editorial: The publication of geoscientific model developments v1.0

In this editorial, GMD Executive Editors assess the lessons learned over the first few years of the journal’s life, and describe some changes to GMD’s editorial policy, which will ensure that the models and model developments are published in such a way that they are of maximum value to the community.

Absorptivity of brown carbon in fresh and photo-chemically aged biomass-burning emissions

Experiments were conducted to investigate light absorption of organic aerosol in fresh and photo-chemically aged biomass-burning emissions.

ACE-FTS observations of acetonitrile in the lower stratosphere

This work reports the first infrared satellite remote-sensing measurements of acetonitrile (CH₃CN) in the Earth’s atmosphere using solar occultation measurements made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) between 2004 and 2011.

ACE-FTS observations of acetonitrile in the lower stratosphere">Read more

A decadal satellite analysis of the origins and impacts of smoke in Colorado

We analyze the record of aerosol optical depth (AOD) measured by the MODerate resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite in combination with surface PM_2.5 to investigate the impact of fires on aerosol loading and air quality over Colorado from 2000 to 2012, and to evaluate the contribution of local versus transported smoke.

LGM permafrost distribution: how well can the latest PMIP multi-model ensembles perform reconstruction?

Here, global-scale frozen ground distribution from the Last Glacial Maximum (LGM) has been reconstructed using multi-model ensembles of global climate models, and then compared with evidence-based knowledge and earlier numerical results.

LGM permafrost distribution: how well can the latest PMIP multi-model ensembles perform reconstruction?">Read more

On the effect of orbital forcing on mid-Pliocene climate, vegetation and ice sheets

We present results from modelling of the mid-Pliocene warm period (3.3–3 million years ago) using the Earth system model of intermediate complexity CLIMBER-2 analysing the effect of changes in boundary conditions as well as of orbital forcing on climate.

Clifford algebra-based structure filtering analysis for geophysical vector fields

A new Clifford algebra-based vector field filtering method, which combines amplitude similarity and direction difference synchronously, is proposed.

MODIS 3 km aerosol product: algorithm and global perspective

After more than a decade of producing a nominal 10 km aerosol product based on the dark target method, the MODerate resolution Imaging Spectroradiometer (MODIS) aerosol team will be releasing a nominal 3 km product as part of their Collection 6 release.

MODIS 3 km aerosol product: algorithm and global perspective">Read more

Carbon farming in hot, dry coastal areas: an option for climate change mitigation

We present a comprehensive, interdisciplinary project which demonstrates that large-scale plantations of Jatropha curcas – if established in hot, dry coastal areas around the world – could capture 17–25 t of carbon dioxide per hectare per year from the atmosphere (over a 20 yr period).

Detailed insight into Arctic climatic variability during MIS 11c at Lake El’gygytgyn, NE Russia

Here we present a detailed multi-proxy record of the climate and environmental evolution at Lake El’gygytgyn, Far East Russian Arctic during the period 430–395 ka covering the marine isotope stage (MIS) 12/11 transition and the thermal maximum of super interglacial MIS 11c.

MIS 11c at Lake El’gygytgyn, NE Russia">Read more