Current covers of AGU Journals. For older covers, see the archives of each journal. High resolution images are available in the issue information PDF of each issue.
Photograph of sunlight illuminating smoke from a traditional cookstove in a rural Indian kitchen. See Grieshop et al. [DOI:10.1002/2017GH000066]
photograph of the JetYak as it approaches the glacier face taken from a helicopter. Inserts
Ceres has plenty of permanently shadowed regions (mapped in blue) at the present day when its obliquity is small. However, due to obliquity changes in the past, only few permanent shadows remain.
The estimated linkages of stream water quality with the land use and hydrologic drivers identify the management targets and priorities to achieve healthy coastal-urban stream ecosystems.
In Rutte et al. [DOI: 10.1002/2016TC004293], image shows (a–d) Panoramic views of the Muskol dome. Distortion increases toward the image edges. Figures 4a and 4b
image shows macrocracks visible within an internal vertical saw-cut face of tuffeau blocks (a) 1,
In Czuba et al. image shows Lidar hillshade highlighting major features (river, bluff, and ravine, each with relevant attributes) incorporated into the model. Inset image shows a 64m bluff; note the canoe for scale. Location and extent is shown in Figure3by a small red box.
Case study of projected changes in rainfall on the Island of Maui, Hawaii, and associated estimates of changes in low flows. (a) Percentage change in average annual rainfall from statistical downscaling models [Timm et al., 2015] at ungaged basins between 1978–2007 and 2071–2099. (b) Percentage change in average annual rainfall from dynamical downscaling models [Zhang et al., 2012; APDRC, 2016] at ungaged basins between 1978–2007 and 2090–2109, Maui Hawaii. (c) Percentage changes in Q70k¯ associated with rainfall A computed using rainfall elasticity ( εx) values from random-effects panel regressions for ungaged basins and from streamflow records for gaging stations. (d) Percentage changes in Q70k¯ associated with rainfall B computed using εx values from fixed effects panel regressions for ungaged basins and from streamflow records for gaged basins. Basins without an estimate of changes in low flow are classified as nonperennial and streams in these basins do not have natural low flows for recent conditions. Some ungaged streams may be misclassified.
In van Marle et al. [DOI: 10.1002/2016GB005445], Van Marle et al. reconstructed fire dynamics from 1973 to 2014 in the Amazon based
Pictured is a measurement campaign in October 2015 using a portable radar interferometer on the Great Aletsch Glacier in Switzerland. The campaign
Two eddy-covariance flux towers at the Harvard Forest in New England where the hemlock woolly adelgid (Adelges tsugae) infestation has resulted in eastern hemlock (Tsuga canadensis) mortality (photo by David A. Orwig).
A plume of ash and steam plume rises from the summit of Popocatepetl Volcano, Mexico, in July 2014.
The change of annual isoprene emission associated with the change in vegetation coverage from the year of 2000 to 2015
Wang et al., conducted the first extensive and comprehensive investigation of sedimentary polycyclic aromatic hydrocarbons (PAHs) concentration, flux, and budget in the continental shelves of the Eastern China Marginal Seas (ECMSs). Source apportionment of PAHs indicated significant regional variation, mainly influenced by socioeconomic differences between north and south China. Deposition flux calculation showed that PAHs flux in the ECMSs and its subregions was higher than the North Gulf of Mexico, Mediterranean, and SW Black Sea (Green column), which suggested that the burial effciency of PAHs in the ECMSs was relatively higher than in the other regions considered. The buried capacity for PAHs in the ECMSs was the highest in the world (Red column), which served as an important global sink of PAHs and plays a significant role in the global PAHs cycle.
In Booth et al., image (a–e) slope maps of the surface evolution of the Oso landslide predicted by a nonlinear model of hillslope sediment flux (equation(1)). Figure6a is 2014 lidar data, while Figures 6b–6e are model results. For comparison, (f) a lidar-derived slope map of the landslide directly southeast of the Oso landslide with a similar size and shape and a predicted age of ~5000 cal years B.P. is presented.
image shows the occurrences of the pseudotachylytes in the Bajiaomiao village. (a–c) The pseudotachylyte veins present
In Lapierre et al., based on an analysis of 1080 lakes distributed across the continental U.S., the image shows that surface water CO2 responds to contrasting drivers related to aquatic primary production, respiration by microorganisms, or terrestrial loadings of carbon depending on the climate and landscape context where these lakes are found. These results show that controls on lake CO2
In Chen et al. [DOI: 10.1002/2016JD026427], figure 1 shows schematic summary of the two mechanisms of interhemispheric transport:
A hot flow anomaly generates global ULF waves in the magnetosphere. Reflected ions (white arrows) from Earth’s bow shock are trapped by a tangential discontinuity (purple dashed line) and drift along it, interact with the incident solar wind ions and form a hot plasma region (yellow region) called Hot Flow Anomaly (HFA). The hot plasma region expands and form shocks (blue arrows) on two sides of the structure. In this study, an HFA was observed by Cluster 1 spacecraft, generating ULF waves in the magnetosphere globally (the red dashed lines represent the undisturbed magnetic field lines, the red solid lines represent the magnetic field lines with ULF waves).
Schematic of the biogeochemical feedbacks and their sign of change associated with warming and increased N deposition. Solid lines represent direct effects, light-colored lines represent indirect effects. Thickness of the lines represent, in a semiquantitative way, the intensity of the perturbation. Warming directly enhances metabolic rates (net primary production (NPP), N2 fixation (N2 fix), and remineralization) and stratification and reduces O2 solubility and meridional overturning circulation (MOC). Intensified stratification reduces ocean ventilation driving additional O2 decline and limits the supply of new nutrients in the euphotic zone. This contrasts the enhanced surface nutrient availability due to faster remineralization and the higher growth rates, resulting in little net change of NPP and N2 fix. Reduced new nutrient inputs lead to a decline in export production (EP), which in turn reduce benthic denitrification (BD) and O2 consumption at depth. However, the combination of the warming-driven processes results in a net O2 reduction, which intensifies water column denitrification (WCD). More N loss via WCD compensated by less N loss via BD and small changes in N2 fix result in little net N inventory change. N2O production decline due to reduced EP is larger than the N2O production increase in low-O2 waters. This, together with stratification-reduced N2O outgassing, circulation slowdown, and human-driven atmospheric N2O increase (N2O anthro) contribute to reduce oceanic N2O emissions (N2O emissions). Nitrogen deposition stimulates NPP but reduces the niche of N2 fixers with a small EP increase. This, in turn, stimulates BD and O2 demand at depth that result in larger WCD. Overall, the atmospheric N inputs are compensated by more N loss via denitrification and reduced N2 fix, with little net effect on N2O production and oceanic emissions. For the combined perturbations, the net sign of change of each process is given by the sum of the signs scaled by the line thickness.