AGU 期刊一周Research Spotlights (Aug 09~Aug 17, 2016)

发布时间:2016-8-19 10:46:55 点击次数:650

I. Atmospheric Sciences

1. Does Water Vapor from Volcanic Eruptions Cause Climate Warming?

By studying past volcanic eruptions, scientists find that the amount of water vapor reaching the stratosphere during moderately explosive eruptions may not be contributing to the greenhouse effect.

II. Geology & Geophysics

1. Unraveling the History of Central Europe's Pannonian Basin

A multidisciplinary model linking the sedimentary and tectonic histories of this structurally complex basin suggests that large amounts of extension occurred there between 20 and 9 million years ago.

2. Characterizing the Faults Beneath Germany

A team of researchers has described how the faults within the German Alpine Molasse Basin initially developed.

3. AGU Expands into Geohealth, Starting with New Journal

The journal GeoHealth, to be launched by the American Geophysical Union and Wiley, will disseminate research relating Earth and environmental sciences to human, agricultural, and environmental health.

III.Hydrology, Cryosphere & Earth Surface

1. What Happens to Methane That Leaks from Abandoned Wells?

Three-dimensional simulations suggest that some aquifers may be more vulnerable to contamination from leaky oil wells than others.

IV.Ocean Sciences

1. Building an Accessible Archive for Water Column Sonar Data

The Water Column Sonar Data Archive aggregates and curates sonar data sets from many sources, giving researchers access to much more information than they could collect on their own.

2. What Steers Antarctica's Largest Current?

Scientists have observed that pressure from current-seafloor encounters drives the direction of the massive Antarctic Circumpolar Current in the Southern Ocean.

V. Climate Change

1. Which Greenhouse Gas Does the Most Damage to Crops?

Models showed that approximately 93% of crop losses over the rest of the century could be caused by non–carbon dioxide emissions, the most damaging of these being methane.

2.Advancing Soil Carbon Cycle Science

Workshop to celebrate 2015–2024 International Decade of Soil; Boulder, Colorado, 14–16 March, 2016

VI. Science Policy & Funding

1. Scientists Bittersweet as Australia Backtracks on Climate Cuts

Researchers welcome the prime minister's move to force an independent research institute to reverse some job cuts but say that the damage to Australia's scientific reputation can't be reversed.

VII.AGU news

1. CLIMATE CHANGE COULD CAUSE MAJOR DECLINE IN ANTARCTIC KRILL HABITAT BY 2100

WASHINGTON, DC — Antarctic krill, small crustaceans key to the Antarctic marine food web, could lose most of their current habitat by the year 2100, according to a new study. Researchers combined climate simulations with a krill growth model to find that changes in water temperature and sea ice in Antarctic waters could shrink krill habitat by as much as 80 percent by the end of the century, potentially causing a decline in krill that could ripple throughout the entire marine food chain.

2. AMERICAN GEOPHYSICAL UNION PARTNERS WITH WILEY TO TAKE ON NEW GEOHEALTH INITIATIVE

WASHINGTON, DC—Geohealth is a rapidly emerging transdisciplinary field that supports the intersection of Earth and environmental sciences with human, agricultural, and environmental health. As a first step in its efforts to support and enable this emerging field, the American Geophysical Union (AGU) announced today the launch of its newest journal,GeoHealth.

VIII. Earth and Space Science

1. Climate modeling suggests Venus may have been habitable

Venus may have had a shallow liquid-water ocean and habitable surface temperatures for up to 2 billion years of its early history, according to computer modeling of the planet’s ancient climate by scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York.

IX. Geophysical Research Letters

1. Intraplate volcanism controlled by back-arc and continental structures in NE Asia inferred from transdimensional Bayesian ambient noise tomography

 Intraplate volcanism adjacent to active continental margins is not simply explained by plate tectonics or plume interaction. Recent volcanoes in northeast (NE) Asia, including NE China and the Korean Peninsula, are characterized by heterogeneous tectonic structures and geochemical compositions. Here we apply a transdimensional Bayesian tomography to estimate high-resolution images of group and phase velocity variations (with periods between 8 and 70 s). The method provides robust estimations of velocity maps, and the reliability of results is tested through carefully designed synthetic recovery experiments. Our maps reveal two sublithospheric low-velocity anomalies that connect back-arc regions (in Japan and Ryukyu Trench) with current margins of continental lithosphere where the volcanoes are distributed. Combined with evidences from previous geochemical and geophysical studies, we argue that the volcanoes are related to the low-velocity structures associated with back-arc processes and preexisting continental lithosphere.

2. Projected changes of Antarctic krill habitat by the end of the 21st century

Climate change is rapidly shaping the living environment of the most abundant keystone species of the Antarctic marine food web, Antarctic krill. Projected future changes for the krill habitat include a sustained increase in ocean temperature and changes in sea ice and chlorophyll a. Here we investigate how these factors affect the early life history of krill and identify the regions around Antarctica where the impact will be greatest. Our tool is a temperature-dependent krill growth model forced by data from comprehensive greenhouse warming simulations. We find that by the year 2100 localized regions along the western Weddell Sea, isolated areas of the Indian Antarctic , and the Amundsen/Bellingshausen Sea will support successful spawning habitats for krill. The failure of potentially successful spawning will have a strong impact on the already declining adult populations with consequences for the Antarctic marine food web, having both ecological and commercial ramifications.

3. Quantifying uncertainties on regional sea level change induced by multidecadal intrinsic oceanic variability

A global eddy-permitting (1/4° resolution) ocean general circulation model is shown to spontaneously generate intrinsic oceanic variability (IOV) up to multidecadal timescales (T > 20 years) under a repeated seasonal atmospheric forcing. In eddy-active regions, the signature of this multidecadal eddy-driven IOV on sea level is substantial, weakly autocorrelated, and is comparable to (and may clearly exceed) the corresponding signature of internal climate variability (ICV) produced by current coupled climate models—whose laminar ocean components may strongly underestimate IOV. Deriving sea level trends from finite-length time series in eddy-active regions yields uncertainties induced by this multidecadal IOV, which are of the same order of magnitude as those due to ICV. A white noise model is proposed to approximate the low-frequency tail of the IOV spectra and could be used to update ICV estimates from current climate simulations and projections.

4. The effects of increasing humidity on heat transport by extratropical waves

This study emphasizes the separate contributions of the warm and cold sectors of extratropical cyclones to poleward heat transport. Aquaplanet simulations are performed with an intermediate complexity climate model in which the response of the atmosphere to a range of values of saturation vapor pressure is assessed. These simulations reveal stronger poleward transport of latent heat in the warm sector as saturation vapor pressure is increased and an unexpected increase in poleward sensible heat transport in the cold sector. The latter results nearly equally from changes in the background stability of the atmosphere at low levels and changes in the temporal correlation between wind and temperature fields throughout the troposphere. Increased stability at low level reduces the likelihood that movement of cooler air over warmer water results in an absolutely unstable temperature profile, leading to less asymmetric damping of temperature and meridional velocity anomalies in cold and warm sectors.

5. Sinuosity of midlatitude atmospheric flow in a warming world

Global warming is expected to affect midlatitude atmospheric dynamics through changes in the equator-to-pole temperature gradient. While the latitudinal expansion of the tropics would induce both a poleward shift and reinforcement of the westerlies, Arctic changes might counterbalance this effect. Beyond position and speed, potential changes in the flow waviness are crucial for midlatitude weather. Here we investigate such changes through an intuitive metric characterizing the flow sinuosity at 50°N. We find that despite a slight increase in recent reanalyses, the midlatitude sinuosity is projected to decrease in response to climate change according to CMIP5 simulations. Recent trends could therefore result from internal variability or different timings of tropical and polar influences. Future uncertainties are dominated by model discrepancies and partially linked to the dispersion in the equator-to-pole temperature gradient response. Our results support the hypothesis that a faster westerly flow is expected to be less sinuous (and vice-versa).

6. The detection of benzene in Saturn's upper atmosphere

The stratosphere of Saturn contains a photochemical haze that appears thicker at the poles and may originate from chemistry driven by the aurora. Models suggest that the formation of hydrocarbon haze is initiated at high altitudes by the production of benzene, which is followed by the formation of heavier ring polycyclic aromatic hydrocarbons. Until now there have been no observations of hydrocarbons or photochemical haze in the production region to constrain these models. We report the first vertical profiles of benzene and constraints on haze opacity in the upper atmosphere of Saturn retrieved from Cassini Ultraviolet Imaging Spectrograph stellar occultations. We detect benzene at several different latitudes and find that the observed abundances of benzene can be produced by solar-driven ion chemistry that is enhanced at high latitudes in the northern hemisphere during spring. We also detect evidence for condensation and haze at high southern latitudes in the polar night.