I.Climate Change

1. What Causes Ecological Shifts?

A new information-processing framework helps researchers tease out the factors driving ecological shifts over short timescales.

https://eos.org/research-spotlights/what-causes-ecological-shifts

2. Rise of Distorted News Puts Climate Scientists on Their Guard

Wary of misleading coverage, some climate researchers are avoiding publicizing results. Others prepare countermeasures to anticipate and combat skewed media reports.

https://eos.org/features/rise-of-distorted-news-puts-climate-scientists-on-their-guard

3. Cosmic Ray Neutrons Reveal Mountain Snowpacks

The first application of aboveground neutron sensing to evaluate alpine snowpacks indicates that this method can reliably detect average snow depth and water content across intermediate distances.

https://eos.org/research-spotlights/cosmic-ray-neutrons-reveal-mountain-snowpacks

4. Summer Rainfall Patterns in East Asia Shift with the Wind

Decades of data reveal the link between westerly winds and year-to-year changes in monsoon rainfall.

https://eos.org/research-spotlights/summer-rainfall-patterns-in-east-asia-shift-with-the-wind

5. Early-Career Scientists Discuss Paleoscience, Future Challenges

3rd PAGES Young Scientists Meeting; Morillo de Tou, Spain, 7–9 May 2017

https://eos.org/meeting-reports/early-career-scientists-discuss-paleoscience-future-challenges

6. Satellite Quantifies Carbon Dioxide from Coal-Fired Power Plants

Using data from NASA’s Orbiting Carbon Observatory 2 satellite, researchers measured emissions of the greenhouse gas from individual coal plants in the United States, India, and South Africa.

https://eos.org/articles/satellite-quantifies-carbon-dioxide-from-coal-fired-power-plants

II. Hazards & Disasters

1. To Understand Future Solar Activity, One Has to Know the Past

Short-term funding strategies present serious problems for programs like solar activity studies, where observations and analysis span decades or longer.

https://eos.org/opinions/to-understand-future-solar-activity-one-has-to-know-the-past

2. An 1888 Volcanic Collapse Becomes a Benchmark for Tsunami Models

When volcanic mountains slide into the sea, they trigger tsunamis. How big are these waves, and how far away can they do damage? Ritter Island provides some answers.

https://eos.org/project-updates/an-1888-volcanic-collapse-becomes-a-benchmark-for-tsunami-models

3. Past FEMA Head Urges Smarter Rebuilding After Natural Disasters

Craig Fugate says the United States has an opportunity to rebuild more resiliently if Congress doesn’t simply provide relief money but also requires rebuilding to higher standards.

https://eos.org/articles/past-fema-head-urges-smarter-rebuilding-after-natural-disasters

III. Ocean Sciences

1. Playing with Water: Humans Are Altering Risk of Nuisance Floods

New research suggests that excessive groundwater usage and damming have changed the natural risk of nuisance floods, for better or worse, in eastern U.S. coastal cities.

https://eos.org/articles/playing-with-water-humans-are-altering-risk-of-nuisance-floods

2. Ocean Dynamics May Drive North Atlantic Temperature Anomalies

A new analysis of sea surface temperature and salinity over several decades seeks to settle the debate on which of two mechanisms underlies the Atlantic Multidecadal Oscillation.

https://eos.org/research-spotlights/ocean-dynamics-may-drive-north-atlantic-temperature-anomalies

IV.Geology & Geophysics

1. Airborne Platforms Help Answer Questions in Polar Geosciences

International Workshop on Airborne Geodesy and Geophysics with Focus on Polar Applications; Dresden, Germany, 19–21 April 2017

https://eos.org/meeting-reports/airborne-platforms-help-answer-questions-in-polar-geosciences

2. Celebrating the 2017 Class of Fellows

American Geophysical Union President-elect Robin Bell will present the newly elected class at the upcoming AGU Fall Meeting.

https://eos.org/agu-news/celebrating-the-2017-class-of-fellows

3. Diversifying the Reviewer Pool

After a successful trial to actively encourage authors to recommend diverse lists of reviewers for their papers, a reminder statement about diversity will now be rolled out across AGU journals.

https://eos.org/agu-news/diversifying-the-reviewer-pool

V. Biogeosciences

1. Is Living Near a Farm Bad for Your Health?

A recent commentary in GeoHealth highlighted the health risks for people living close to large-scale livestock farms.

https://eos.org/editors-vox/is-living-near-a-farm-bad-for-your-health

2. Open-Source Tool Aims to Boost Confidence in Ice Sheet Models

The software could help strengthen ice sheet models to provide a better basis for policy decisions.

https://eos.org/research-spotlights/open-source-tool-aims-to-boost-confidence-in-ice-sheet-models

VI.Space & Planets

1. New Study Highlights ‘Hidden Figure’ of Sun-Watchers

New study highlights ‘hidden figure’ of sun-watchers.

https://eos.org/scientific-press/new-study-highlights-hidden-figure-of-sun-watchers

2. More Discoveries in the Cards from Defunct Comet Mission

A year after the end of the Rosetta mission, the real scientific fun begins.

https://eos.org/articles/more-discoveries-in-the-cards-from-defunct-comet-mission

3. Probing the Cusps of Saturn's Magnetic Field

Data from the Cassini spacecraft show that the cusp regions of Saturn’s magnetic field—where it connects to the Sun’s magnetic field—have similarities to Earth’s and also intriguing differences.

https://eos.org/research-spotlights/probing-the-cusps-of-saturns-magnetic-field

4. Ten New Frontiers in the Solar System and Beyond

Humanity's reach has extended from the surface of Earth to the very edge of our solar system, even to exoplanets far into space. What’s next in our journey into the unknown?

https://eos.org/features/ten-new-frontiers-in-the-solar-system-and-beyond

5. Choosing a Lunar Landing Site

A recent article in JGR: Planets described the geological characteristics of two candidate sites for the upcoming Chinese mission to the Moon.

https://eos.org/editors-vox/choosing-a-lunar-landing-site

VII.Geophysical Research Letters

1. Global Response of Clear-Air Turbulence to Climate Change

Clear-air turbulence (CAT) is one of the largest causes of weather-related aviation incidents. Here we use climate model simulations to study the impact that climate change could have on global CAT by the period 2050–2080. We extend previous work by analyzing eight geographic regions, two flight levels, five turbulence strength categories, and four seasons. We find large relative increases in CAT, especially in the midlatitudes in both hemispheres, with some regions experiencing several hundred per cent more turbulence. The busiest international airspace experiences the largest increases, with the volume of severe CAT approximately doubling over North America, the North Pacific, and Europe. Over the North Atlantic, severe CAT in future becomes as common as moderate CAT historically. These results highlight the increasing need to improve operational CAT forecasts and to use them effectively in flight planning, to limit discomfort and injuries among passengers and crew.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL074618/full

2. Seasonal Noise Versus Subseasonal Signal: Forecasts of California Precipitation During the Unusual Winters of 2015–2016 and 2016–2017

Subseasonal forecasts of California precipitation during the unusual winters of 2015–2016 and 2016–2017 are examined in this study. It is shown that two different ensemble forecast systems were able to predict monthly precipitation anomalies in California during these periods with some skill in forecasts initialized near or at the start of the month. The unexpected anomalies in February 2016, as well as in January and February 2017, were associated with shifts in the position of the jet stream over the northeast Pacific in a manner broadly consistent with associations found in larger ensembles of forecasts. These results support the broader notion that what is unpredictable atmospheric noise at the seasonal time scale can become predictable signal at the subseasonal time scale, despite that the lead times and verification averaging times associated with these forecasts are outside the predictability horizons of canonical midrange weather forecasting.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL075052/full

3. Wastewater Disposal and the Earthquake Sequences During 2016 Near Fairview, Pawnee, and Cushing, Oklahoma

Each of the three earthquake sequences in Oklahoma in 2016—Fairview, Pawnee, and Cushing—appears to have been induced by high-volume wastewater disposal within 10 km. The Fairview M5.1 main shock was part of a 2 year sequence of more than 150 events of M3, or greater; the main shock accounted for about half of the total moment. The foreshocks and aftershocks of the M5.8 Pawnee earthquake were too small and too few to contribute significantly to the cumulative moment; instead, nearly all of the moment induced by wastewater injection was focused on the main shock. The M5.0 Cushing event is part of a sequence that includes 48 earthquakes of M3, or greater, that are mostly foreshocks. The cumulative moment for each of the three sequences during 2016, as well as that for the 2011 Prague, Oklahoma, and nine other sequences representing a broad range of injected volume, are all limited by the total volumes of wastewater injected locally.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL075258/full

4. Oxygen Ebullition From Lakes

The exchange of oxygen between lakes and the atmosphere is assumed to be driven by diffusion. Here we show that lakes can emit significant amounts of O2 by emerging gas bubbles—a process called ebullition. We found very high proportions of 17 ± 10% O2 (maximum 34%) in emerging gas bubbles in two shallow eutrophic reservoirs. In the studied reservoirs, O2 emission by ebullition was of similar magnitude as diffusive O2 fluxes. By reanalyzing previous studies, we show that the process is ubiquitous and probably quantitatively relevant in many places. We present evidence that O2 in bubbles originates both from photosynthetic oxygen production and hence bubble formation in the oxic water and from stripping by emerging methane bubbles. Ebullition can turn lakes undersaturated in respect to the atmosphere into a net O2 source. Neglecting O2 ebullition leads to an overestimation of lake internal respiration.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL074591/full

5. The Influence of Gravity on the Displacement Field Produced by Fault Slip

We calculated surface displacements produced by a synthetic megathrust earthquake using two spherical, layered, elastic dislocation models which differ only in that one model accounts for the coupling between elasticity and gravity and the other does not. We show that including gravity perturbs the displacement field differently in the near-, medium-, and far-fields. As a result, slip inversions based on an Earth model without gravity cannot simultaneously fit the near-, medium- and far-field displacements generated using a forward model including gravity. This suggests that the spatially systematic misfits between observations and dislocation predictions seen in the literature arise, at least in part, because these studies are based on models that neglect gravity. Although the magnitude of the far-field displacements is small compared to those of the near-field, our slip inversions show the most improvement when we both up-weight the far-field observations and use a physically consistent model in the inversion.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL074113/full

6. Can the Ocean's Heat Engine Control Horizontal Circulation? Insights From the Caspian Sea

We investigate the role of the ocean's heat engine in setting horizontal circulation using a numerical model of the Caspian Sea. The Caspian Sea can be seen as a virtual laboratory—a compromise between realistic global models that are hampered by long equilibration times and idealized basin geometry models, which are not constrained by observations. We find that increases in vertical mixing drive stronger thermally direct overturning and consequent conversion of available potential to kinetic energy. Numerical solutions with water mass structures closest to observations overturn 0.02–0.04 × 106 m3/s (sverdrup) representing the first estimate of Caspian Sea overturning. Our results also suggest that the overturning is thermally forced increasing in intensity with increasing vertical diffusivity. Finally, stronger thermally direct overturning is associated with a stronger horizontal circulation in the Caspian Sea. This suggests that the ocean's heat engine can strongly impact broader horizontal circulations in the ocean.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL075182/full

7. Relative Humidity Has Uneven Effects on Shifts From Snow to Rain Over the Western U.S.

Predicting the phase of precipitation is fundamental to water supply and hazard forecasting. Phase prediction methods (PPMs) are used to predict snow fraction, or the ratio of snowfall to total precipitation. Common temperature-based regression (Dai method) and threshold at freezing (0°C) PPMs had comparable accuracy to a humidity-based PPM (TRH method) using 6 and 24 h observations. Using a daily climate data set from 1980 to 2015, the TRH method estimates 14% and 6% greater precipitation-weighted snow fraction than the 0°C and Dai methods, respectively. The TRH method predicts four times less area with declining snow fraction than the Dai method (2.1% and 8.1% of the study domain, respectively) from 1980 to 2015, with the largest differences in the Cascade and Sierra Nevada mountains and southwestern U.S. Future Representative Concentration Pathway (RCP) 8.5 projections suggest warming temperatures of 4.2°C and declining relative humidity of 1% over the 21st century. The TRH method predicts a smaller reduction in snow fraction than temperature-only PPMs by 2100, consistent with lower humidity buffering declines in snow fraction caused by regional warming.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL075046/full

8. In Situ Stress and Pore Pressure in the Deep Interior of the Nankai Accretionary Prism, Integrated Ocean Drilling Program Site C0002

Strength and slip behaviors of subduction megathrusts are controlled by the physical properties and stress state not only of the fault zones themselves but also the adjacent wall rocks in overriding and subducting plates. In the Nankai Trough, a 3 km deep riser borehole at Integrated Ocean Drilling Program Site C0002 was drilled into the Kumano fore-arc basin and the underlying accretionary prism. We quantify the full in situ stress tensor and pore pressure at Site C0002 by integrating drilling data, geophysical logging, and downhole measurements using empirical relations that describe sediment compaction behavior as a function of loading path. The Kumano Basin is loaded in uniaxial vertical strain conditions, whereas the prism below is loaded with greater differential stress, has a modestly elevated pore pressure, and lies in a strike-slip faulting regime. This can be reconciled with slip on the megathrust fault if the horizontal stresses vary with time or depth and/or if shear stress along the megathrust is low.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL075127/full

9. A new approach developed to study variability in North African dust transport routes over the Atlantic during 2001–2015

We investigated the variability in the North African dust transport routes over the Atlantic (NAD routes) by extracting the dust transport central axis using Moderate Resolution Imaging Spectroradiometer aerosol data for 2001–2015. The results showed that the NAD routes can be classified into two regimes, a southern route centered at the southernmost position of 6.08 ± 1.12°N during November to March and a northern route centered at the northernmost position of 18.21 ± 1.04°N during April to October. In the southern route, large intervariation was correlated with the Intertropical Convergence Zone (ITCZ) and North Atlantic Oscillation (NAO), but the ITCZ and NAO jointly explained only 38% of the variation. In the northern route, the ITCZ alone explained 67% of the intervariation. The extracted trends during 2001–2015 exhibited a northward shift of 1.68° for the southern route and of 0.52° for the northern route. The causes for the shift were also examined.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL074478/full

10. Interannual Variability of Methane and Nitrous Oxide in the North Pacific Subtropical Gyre

The temporal variability of two important greenhouse gases, methane (CH4) and nitrous oxide (N2O), is reported for the upper water column at Station ALOHA in the North Pacific Subtropical Gyre. Measured concentrations of N2O conform to predicted values with an increase in saturation during the summer period. In contrast, CH4 is less predictable and shows an approximate 2 year transition from a state of oversaturation in surface waters to equilibrium values in 2015, implying a change in net CH4 production. The decrease in CH4 followed on from fluctuations in phosphate concentrations supporting the hypothesized link between microbial metabolism of phosphorus and the global biogeochemical cycle of CH4. At this current time, future trends in the net CH4 production in the North Pacific Subtropical Gyre are uncertain and specifically whether the surface ocean will be a net source or sink for CH4.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL074458/full

VIII. AGU Blogs

1. Monday Geology Picture: Posing with Pahoehoe

First of all, for this week’s “Monday Geology Picture” enjoy this fantastic picture of me sitting on some pahoehoe lava earlier this year, when I visited Réunion Island back in March. Second of all, let me provide a little explanation about why I have been terribly negligent of this blog over the past few months, despite my best intentions at the beginning of the year.

http://blogs.agu.org/georneys/2017/10/02/monday-geology-picture-posing-pahoehoe/

2. California Burning on Such A Snowy Day

The snow in Denver and the firestorm in California today are intimately connected. When a strong high-pressure system moves into Utah and Colorado, the winds blow from the northeast over the Sierra’s and the Coast Range in California. Air has weight and it accelerates as it rolls downhill and it also accelerates as it is funnelled into the canyons. The result is an air mass that was already dry, being warmed by compression as it falls, and this drops the relative humidity to even lower levels.

http://blogs.agu.org/wildwildscience/2017/10/10/california-burning-snowy-day/

3. Finding far-north lynx den part of cycle study

UAF graduate student Claire Montgomerie handles a lynx kitten she found at a den site near Wiseman this summer. In her study of one of the farthest north lynx populations in North America this summer, Claire Montgomerie used her ears. While looking at the satellite tracker a female lynx was wearing, Montgomerie saw the animal was hanging around a hillside north of the Arctic Circle, not far from Coldfoot.

http://blogs.agu.org/thefield/2017/10/06/finding-far-north-lynx-den-part-cycle-study/

4. Old Faithful’s geological heart revealed

Old Faithful is Yellowstone National Park's most famous landmark. Millions of visitors come to the park every year to see the geyser erupt every 44-125 minutes. But despite Old Faithful's fame, relatively little was known about the geologic anatomy of the structure and the fluid pathways that fuel the geyser below the surface. Until now.

http://blogs.agu.org/geospace/2017/10/06/old-faithfuls-geological-heart-revealed/

IX. AGU NEWS

1.AGU FALL MEETING IN NEW ORLEANS: ABSTRACTS AND SESSIONS NOW ONLINE; BOOK HOTELS BY 15 NOVEMBER

WASHINGTON, DC — Discover the latest Earth and space science news at the 50th annual AGU Fall Meeting this December, when about 24,000 attendees from around the globe are expected to assemble for the largest worldwide conference in the Earth and space sciences.

https://news.agu.org/press-release/agu-fall-meeting-in-new-orleans-abstracts-and-sessions-now-online-book-hotels-by-15-november/