I.Climate Change

1.Restored Wetlands Could Lower Local Surface Temperatures

A 3-year study of wetlands and cropland in a major California delta highlights the need to consider the physical effects of vegetation when planning land use changes.

https://eos.org/research-spotlights/restored-wetlands-could-lower-local-surface-temperatures

2.Countergeoengineering Could Ease or Escalate Climate Tensions

Researchers systematically consider the feasibility and political implications of future strategies to counteract temperature-lowering solar geoengineering efforts.

https://eos.org/research-spotlights/countergeoengineering-could-ease-or-escalate-climate-tensions

3.Better Plant Data at the Root of Ecosystem Models

Fine roots are complex and dynamic structures that serve many critical roles for land plants. Their well-known importance for acquiring water and nutrients and associations with soil microbes underpin many terrestrial processes, including the movement of carbon, nutrients, and water through terrestrial ecosystems.

https://eos.org/project-updates/better-plant-data-at-the-root-of-ecosystem-models

4.What Is a Nuisance Flood, Exactly?

A more precise definition could help cities and governments prepare and respond to hazards.

https://eos.org/research-spotlights/what-is-a-nuisance-flood-exactly

II.Hazards & Disasters

1.How Forecasting Models Are Changing the Way We Fight Fires

Eos speaks with Andy Edman, western region chief of the Science and Technology Infusion Division at the National Weather Service, about how the agency is helping wildfire crews fight fires from space.

https://eos.org/articles/how-forecasting-models-are-changing-the-way-we-fight-fires

2.Hail Causes the Most Storm Damage Costs Across North America

The icy weather phenomenon leads to more than $10 billion in damages each year. Nonetheless, research on hail is lacking, scientists say.

https://eos.org/articles/hail-causes-the-most-storm-damage-costs-across-north-america

III.Science Policy

1.Countergeoengineering Could Ease or Escalate Climate Tensions

Researchers systematically consider the feasibility and political implications of future strategies to counteract temperature-lowering solar geoengineering efforts.

https://eos.org/research-spotlights/countergeoengineering-could-ease-or-escalate-climate-tensions

VI.Space & Planets

1.New Kind of Aurora Is not an Aurora at All

Thin ribbons of purple and white light that sometimes appear in the night sky were dubbed a new type of aurora when brought to scientists' attention in 2016. But new research suggests these mysterious streams of light are not an aurora at all but an entirely new celestial phenomenon.

https://eos.org/scientific-press/new-kind-of-aurora-is-not-an-aurora-at-all

V.Education

1.Preparing Graduate Students for STEM Careers Outside Academia

Most STEM graduates don't primarily do research or work in academia after they earn a Ph.D. How do we prepare those students for the multitude of other careers they could pursue?

https://eos.org/opinions/preparing-graduate-students-for-stem-careers-outside-academia

VI.Geophysical Research Letters

1.Numerical modeling of plant‐root controls on gravel‐bed river morphodynamics

The role of vegetation in shaping the geomorphology of rivers, deltas, along with tidal and estuarine environments is widely recognized. While mutual interactions between flow, plant canopy and morphodynamics have been extensively investigated, similar studies considering plant roots are limited. Here, we present results from numerical model that quantify the feedbacks of both the above‐ and below‐ground vegetation on gravel‐bed river (GBR) morphodynamics. Plant‐root biogeomorphic feedbacks, i.e. uprooting and root‐enhanced riverbed cohesion, are quantified through the description of the vertical root distribution. By investigating the evolution of the riverbed of a straight gravel channel with a vegetated patch, we show that uprooting is the primary plant‐root biogeomorphic feedback determining the evolution of the riverbed and the competing influence of the potential flow erosion versus uprooting depth mediates the plant‐root controls on morphodynamics. These findings broaden our understanding on the role played by plant roots on GBR morphodynamics.

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL078696

2.Standing Alfvén waves in Jupiter's magnetosphere as a source of ∼10‐60 minute quasi‐periodic pulsations

Energy transport inside the giant magnetosphere at Jupiter is poorly understood. Since the Pioneer era, mysterious quasi‐periodic (QP) pulsations have been reported. Early publications successfully modelled case‐studies of ∼60‐minute (rest‐frame) pulsations as standing Alfvén waves. Since then, the range of periods has increased to ∼10‐60 minutes, spanning multiple data sets. More work is required to assess whether a common QP modulation mechanism is capable of explaining the full range of wave periods. Here we have modelled standing Alfvén waves to compute the natural periods of the Jovian magnetosphere, for varying plasma sheet thicknesses, field line lengths, and Alfvén speeds. We show that variability in the plasma sheet produces eigenperiods that are consistent with all the reported observations. At least the first half‐dozen harmonics (excluding the fundamental) may contribute but are indistinguishable in our analysis. We suggest that all QP pulsations reported at Jupiter may be explained by standing Alfvén waves.

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL078891

3.Lake surface water temperature change over the Tibetan Plateau from 2001–2015: A sensitive indicator of the warming climate

The Tibetan Plateau (TP) plays a significant role in the Earth's climate system. This letter examines the nighttime lake surface water temperature (LSWT) of 374 lakes (≥10 km2each) over the TP for the past 15 years (2001–2015). An overall warming trend (0.037 °C/yr) is found and it is consistent with the warming air temperature (0.036 °C/yr) over the TP, with the vast majority of the lakes (70%, with 28% of which are significant) showing warming (0.076 °C/yr) and the rest (30%, with 37% of which are significant) showing cooling (‐0.053 °C/yr). This astonishing contrast was controlled by different water sources recharging these lakes: 1) warming LSWT due to increased precipitation (central and northern TP) or permafrost degradation (northwestern TP) and 2) cooling LSWT due to increased glacier meltwater (southwestern TP), revealing LSWT a sensitive indicator to climate change that triggered different regional responses in precipitation, permafrost, and glacier changes over the TP. This study helps improve our understanding of high altitude lakes and their changing mechanisms under the warming climate.

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL078601

4.Ocean circulation reduces the Hadley cell response to increased greenhouse gases

The Hadley cell (HC) plays an important role in setting the strength and position of the hydrological cycle. Climate projections show a weakening of the HC, together with widening of its vertical and meridional extents. These changes are projected to have profound global climatic impacts. Current theories for the HC response to increased greenhouse gases account only for atmospheric and oceanic thermodynamic changes, but not for oceanic circulation changes. Here, the effects of ocean circulation changes on the HC response to increased greenhouse gases are examined by comparing fully‐coupled and slab‐ocean model configurations. By reducing the warming of both the sea surface and the atmosphere, changes in ocean circulation reduce the HC response to increased CO2 concentrations. This reduced warming suppresses convective heating, which reduces the weakening of the HC and the stabilization at low latitudes, and thus also reduces the meridional (in the Southern Hemisphere) and vertical HC expansion.

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL079070

VII.AGU Blogs

1.High resolution imagery of the Pashgor debris flow in Afghanistan

Dear Dave, It was a Jkulhlaup (an arid variation!): In this case the collapse of a supraglacial lake over a debris covered glacier, probably by breaking down an ice barrier due to an excess of hydrostatic pressure. It did not happened before probably because the well visible supraglacial hollow that hosted the lake (sometimes described as thermokarst) it is large and only with excessive snow melt could reach the critical depth to overcome the needed pressure to lift the mix of glacier ice and debris. In fact your last image shows that the lake exceeded the size of the hollow that in many older images showed accumulation of water, but with smaller area covered by it. I cannot send you the images that prove this, but I posted a comment in twitter with an image edited showing the glacier characteristics. It is what we locally call complex glacier system as it shows the transition form a ice-exposed part to a debris-covered ice and then into a rock.glacier, which due to its larger debris concentration cannot be floated, but there are case where ice concentration of rock glaciers in Chile reach 99%. regards.

https://blogs.agu.org/landslideblog/2018/08/22/pashgor-1/

2.This is How You Communicate Science

Katharine Hayhoe has the rare quality of being an excellent scientist and a great communicator. You should watch her Global Weirding videos on YouTube. (Teachers, these are great resources.)

Dr. Hayhoe's recent video about taking the politics out of energy is superb, and I urge you to share it. I'll let you in on a little secret: Meteorologists like me who work on TV are impressed by anyone who is really good at science communication because we do it every day and know how hard it is. Dr. Hayhoe has rock-star status among us because she's so good at it.

https://blogs.agu.org/wildwildscience/2018/08/22/this-is-how-you-communicate-science/