Current AGU Journal Covers

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.

40Ar/39Ar geochronology reveals rapid change from plume-assisted to stress-dependent volcanism in the Newer Volcanic Province, SE Australia in G-Cubed

In Oostingh et al., image shows examples of volcanic alignment and geomorphology interpretations. (a) Satellite image of Mt Eccles and (b) interpreted alignment direction. (c) Satellite image of Lake Cartcarrong (maar) and (d) interpreted elongation of the maar structure with preferred orientation.

MAVEN observations of a giant ionospheric flux rope near Mars resulting from interaction between the crustal and interplanetary draped magnetic fields in JGR: Space Physics

MAVEN observation of a giant ionospheric flux rope near Mars, showing the threedimensional whisker plots of the observed magnetic

fields along the spacecraft trajectory (rainbow), viewed from the local time of 10:45 and the MSO latitude of −10°. Blue, green, and red solid
lines are the projected X
mso
, Y
mso
, and Z
mso
axes, respectively. The correspondent times are shown as the rainbow coloring of the magnetic field
along the trajectory, with the flux rope in magenta, and the whisker length is proportional to the field strength. The blue‐red background is a
crustal magnetic field model.

Pacific-Atlantic Ocean influence on wildfires in northeast China (1774 to 2010) in GRL

Fire-scarred Dahurian larch from the Daxing’an Mountains in northeast China.

Seasonal and interannual variability of the Eastern Tropical Pacific Fresh Pool in JGR: Oceans

Guimbar et al., investigated the eastern tropical fresh pool (EPFP) spatial and temporal dynamics. The maximal surface extension of the EPFP exhibits a very large interannual variability. Over the past decade, two extreme events occurred, clearly related to the El Niño-Southern Oscillation (ENSO) phases with associated anomalies of precipitation, surface currents, and trade wind in the central Pacific. In particular, changes of the atmospheric freshwater fluxes and ocean surface currents during winter 2014 seems to trigger the onset of an abnormal fresh event related to the strong El Niño 2014–2015, leading to these unprecedented maximum values of the EPFP maximum extent (October-November) in 2014 and 2015.

Stable isotopes in atmospheric water vapor and applications to the hydrologic cycle in Reviews of Geophysics

Galewsky et al. reviews how the isotopic composition of water vapor is impacted by deep convection and how it behaves within

several tropical weather and climate features. a) Deep convection depletes the lower troposphere through convective downdrafts and diffusive exchanges between rain
drops and vapor, and enriches the upper troposphere through condensate detrainment. b) In the context of a monsoon system, deep convection depletes the water
vapor along the monsoon flow, whereas continental recycling acts to reenrich it. c) In the context of the Madden-Julian Oscillation, the lower and middle tropospheric
water vapor is most enriched before the active phase due to the effect of shallow convection. It becomes more depleted during the active phase due to the effect of deep
convection. Finally, it is most depleted after the active phase when the cloud systems are dominated by their stratiform components. d) In tropical cyclones, diffusive
exchanges between rain drops and vapor lead to strongly depleted water vapor in the rain bands, whereas evaporation and sea spray explain the local maximum in the
eye. Galewsky et al reviews the implications of these properties to better understand convective processes and more generally the hydrological cycle.

Modeling geomagnetic induction hazards using a 3-D electrical conductivity model of Australia in Space Weather

Magnitude of regional electric field component (E

y
associated with M
yx
) and
telluric vectors of real e
x
for a northerly polarization mode for |B| = 1 nT at a period of 360 s.

Using large eddy simulations to reveal the size, strength, and phase of updraft and downdraft cores of an Arctic mixed-phase stratocumulus cloud in JGR: Atmospheres

In Roesler et al., total condensate (precipitating rain and snow and nonprecipitating water and ice) and the vertical velocity at 12 h into the simulation for the (left) 1.5 TKE scheme and the (right) CLUBB scheme. The total condensate is shown in the rainbow color bar, and the vertical velocity is shown with the blue-to-red color bar.

New geochronology constraints on timing and depth of the ancient earthquakes along the Longmen Shan fault belt, eastern Tibet in Tectonics

image shows the occurrences of the pseudotachylytes in the Bajiaomiao village. (a–c) The pseudotachylyte veins present

in the cataclasite with S-C fabrics, (d and e) small injection veins, (f and g) veinlets and network veins, (h and i) foliated breccias with preferred orientation of fractures and
fragments that indicate a thrust sense in the field, and (j–l) drilling sites and pieces of drill cores. Drill holes shown in Figures 3a and 3b are 2.5 cm in diameter and 12 cm in
Figure 3j. Abbreviation: Pst–pseudotachylyte, Cc–cataclasite, Cf–clast fragment.

Ceres's obliquity history and its implications for the permanently shadowed regions in GRL

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.

Increased water yield due to the hemlock woolly adelgid infestation in New England in GRL

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).

Integrating uncertainty propagation in GNSS radio occultation retrieval: From bending angle to dry-air atmospheric profiles in Earth and Space Science

 In Schwarz et al. [DOI: 10.1002/2016EA000234], image shows error correlation matrices from CP and MC methods: (a) Covariance propagated R and (b) Monte Carlo propagated R MC αs for statistically optimized bending angle, (c) propagated R r and (d) Monte Carlo R MC Nr for retrieved refractivity, (e) propagated R pdr and (f) Monte Carlo R MC pdr for retrieved dry pressure, and (g) propagated R Tdr and (h) Monte Carlo R MC Tdr for retrieved dry temperature.

Fidelity of the Sr/Ca proxy in recording ocean temperature in the western Atlantic coral Siderastrea siderea in G-Cubed

In Kufner et al. [DOI: 10.1002/2016GC006640], image shows an example of one of the 39 Siderastrea siderea colonies included in this study (a) attached

to a calcication monitoring block with a temperature logger (black, on left) on the Fowey Rocks reef crest, and (b) slabbed in half showing Alizarin Red-S stain
lines (pink) marking 29 April 2011 (lower line) and 9 May 2012 (upper line). The upper surface of the slab marks the collection date of 16 May 2013. Scale bar
on left of Figure 1b is a cm ruler with mm markings. (c) Inset box from Figure 1b with annual cycle of Sr/Ca in two replicate drill-paths (blue and green lines)
between the stain lines. Y axis is reversed so that Sr/Ca values (mmol mol
–1
) indicating warmer values are up. X axis is time (decimal years).

Structure and dynamics of a subglacial discharge plume in a Greenlandic fjord in JGR: Oceans

photograph of the JetYak as it approaches the glacier face taken from a helicopter. Inserts

show a picture of the JetYak and of the boat from which it was controlled.

Observational properties of dayside throat aurora and implications on the possible generation mechanisms in JGR: Space Physics

Observational properties of a newly discovered auroral form near local noon, called throat aurora, revealing combined contributions from inside and outside of the magnetosphere on the generation. The image gives a schematic summarizing the physical process leading to the formation of throat aurora.

Monitoring rock freezing and thawing by novel geoelectrical and acoustic techniques in JGR: Earth Surface

image shows macrocracks visible within an internal vertical saw-cut face of tuffeau blocks (a) 1,

(b) 3, (c) 4, and (d) 5. Blocks are encased in a layer of fiberglass. Ruler in centimeters.

Sorting out compositional trends in sedimentary rocks of the Bradbury group (Aeolis Palus), Gale crater, Mars in JGR: Planets

In Siebach et al. MAHLI image examples of each of the textural classes of rocks in the Bradbury group and (h) the Murray mudstone in the Mount Sharp group. White scale bars are 1 cm across. Classes were divided on the basis of grain size and/or surface texture and coloring and include (Figure 2a) Sheepbed mudstone (10 APXS analyses; example is Wernecke_preDRT, sol 168), exposed in Yellowknife Bay with grains finer than the limit of resolution; (Figure 2b) fine sandstone (15 APXS analyses; example is Aillik1, sol 322), well-sorted siltstones to sandstones; (Figure 2c) sandstone (22 APXS analyses; example is Gillespie_Lake, sol 132), medium to pebbly sandstones; (Figure 2d) conglomerate (15 APXS analyses; example is Bardin_Bluffs, sol 394), primary grain sizes >1 mm, rounded grains, clasts up to 6 cm; (Figure 2e) uncertain (13 APXS analyses; example is Morehouse, sol 503), float rocks with poorly defined grain boundaries, sometimes weather like conglomerates; (Figure 2f) possible igneous (4 APXS analyses; example is Clinton, sol 512), small group of float rocks and one clast in a conglomerate with porphyritic textures, shortened to igneous in plot legends; (Figure 2g) diagenetic (36 APXS analyses; example is CumberlandNewRP_LIBs, sol 277), rocks with clearly diagenetic textures including preferential cementation and fracture fills; and (Figure 2h) Murray mudstone (27 APXS analyses; example is Punchbowl2, sol 813), mudstone observed at

Pahrump Hills in Mount Sharp group, fine grained with potential secondary crystal structures.

Further evidence for early lunar magnetism from troctolite 76535 in JGR: Planets

In Garrick-Bethell et al. [DOI: 10.1002/2016JE005154], photographs of two opposite faces of 76535, 153 are shown. Lines indicate the approximate

sizes and locations of subsamples 1, 2, and 3.

Fault-bound valley associated with the Rembrandt basin on Mercury in GRL

Mercurys great valley revealed in a 3D perspective view using a high-resolution digital elevation model derived from stereo images obtained by NASAs MESSENGER spacecraft. Below the perspective view is a high-incidence angle image mosaic of the region. Mercurys great valley is over 1,000 km long, extends into the Rembrandt basin, and is bound on one side by Enterprise Rupes, the largest fault scarp on Mercury. The vertical exaggeration is 20X. See also Watters et al., doi: 10.1002/2016GL070205. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/German Aerospace Center–DLR/Smithsonian Institution.

Holocene history of deep-seated landsliding in the North Fork Stillaguamish River valley from surface roughness analysis, radiocarbon dating, and numerical landscape evolution modeling in JGR: Earth Surface

 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)). Figure6a 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.

Earth's Future in Earth's Future

A transdisciplinary, open-access science journal,

Earths Future examines the state of the planet and its inhabitants, and
the predictions of its future. The journal assesses the challenges and
opportunities associated with regional and global change in an era
where humans dominate Earths environment, resources and ecosys-
tems. It publishes peer-reviewed articles, re views and (short and long-
form) commentaries in areas that include water, air, food, energy, haz-
ards, climate, ecosystems, human health and demographics, among
others. Contributions focus on Earth as an interconnected, evolving sys-
tem to inform researchers, policy makers and the public on the science
of the Anthropocene.