I. Climate Change

1.Better Data for Modeling the Sun's Influence on Climate

Several international initiatives are working to stitch together data describing solar forcing of Earth's climate. Their objective is to improve understanding of climate response to solar variability.

https://eos.org/project-updates/better-data-for-modeling-the-suns-influence-on-climate

2.Massive Ocean Waves May Play a Role in Nuisance Flooding

When huge planetary waves that spawn in the open ocean reach land, they can raise local sea levels along the coast. Could tracking these waves help scientists predict flooding months in advance?

https://eos.org/articles/massive-ocean-waves-may-play-a-role-in-nuisance-flooding

II.Hazards&Disasters

1. Earthquake Precursors, Processes, and Predictions

A new book presents various studies that may establish a link between earthquakes and different types of precursor signals from the Earth, atmosphere and space.

https://eos.org/editors-vox/earthquake-precursors-processes-and-predictions

2.Scientists Meet to Review Preparations for Satellite Launch

Center for Satellite Applications and Research JPSS 2017 Annual Science Team Meeting; College Park, Maryland, 14–18 August 2017

https://eos.org/meeting-reports/scientists-meet-to-review-preparations-for-satellite-launch

III. Space&Planets

1.How Hot Is Europa? Now There's a Map for That

The new global map of Europa's surface heat also highlighted one spot on the moon that is inexplicably cold.

https://eos.org/articles/how-hot-is-europa-now-theres-a-map-for-that

1.Hubble Observes Energetic Light Show at Saturn's North Pole

The images provide astronomers with the most comprehensive picture so far of Saturn’s northern aurora.

https://eos.org/scientific-press/hubble-observes-energetic-light-show-at-saturns-north-pole

IV.Biogeosciences

1.Impacts of El Niño to Intensify as Climate Warms, New Study Finds

Swings from El Niño to La Niña are likely to become wilder, with far-reaching consequences for crop yields, fire risk, and heating and cooling demand.

https://eos.org/scientific-press/impacts-of-el-nino-to-intensify-as-climate-warms-new-study-finds

2.Human Activities Create Corridors of Change in Aquatic Zones

Canals, dammed reservoirs, irrigation ditches, and pollution are changing species diversity, microbial communities, and nutrient levels in aquatic zones across the planet.

https://eos.org/opinions/human-activities-create-corridors-of-change-in-aquatic-zones

V. Geophysical Research Letters

1.Orography drives the semi‐stationary West Australian summer trough

During the summer months, there is a semi‐permanent trough in the low‐level easterlies over the west coast of Australia. This "West Coast Trough" plays an important role in summer severe weather in western Australia including thunderstorms and severe heatwaves. The land‐sea contrast is believed to be the driver of the location of this trough. As land‐masses are warming more quickly than their surrounding oceans, it is timely to re‐address the drivers of the location and intensity of this important climatological feature. Using a twenty‐year regional climate modelling simulation, we show that Australian orography is critical to the accurate representation of the trough in climate models, in contrast to earlier low‐resolution studies.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079312

2.Catchment drainage network scaling laws found experimentally in overland flow morphologies

The scaling relation between the drainage area and stream length (Hack's law), along with exceedance probabilities of drainage area, discharge and upstream flow network length are well known for channelized fluvial regions. We report here on a laboratory experiment on an eroding unconsolidated sediment for which no channeling occurred. Laser scanning was used to capture the morphological evolution of the sediment. High intensity, spatially non‐uniform rainfall ensured that the morphology changed substantially over the 16‐h experiment. Based on the surface scans and precipitation distribution, overland flow was estimated with the D8 algorithm, which outputs a flow network that was analyzed statistically. The abovementioned scaling and exceedance probability relationships for this overland flow network are the same as those found for large scale catchments and for laboratory experiments with observable channels. In addition, the scaling laws were temporally invariant, even though the network dynamically changed over the course of experiment.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078351

3.Pitch‐angle scattering and loss of radiation belt electrons in broadband electromagnetic waves

A magnetic conjunction between Van Allen Probes spacecraft and the BARREL balloon array reveals the simultaneous occurrence of broadband Alfvénic fluctuations and multi‐timescale modulation of enhanced atmospheric X‐ray bremsstrahlung emission. The properties of the Alfvenic fluctuations are used to build a model for pitch‐angle scattering in the outer radiation belt on electron gyro‐radii scale field structures. It is shown that this scattering may lead to the transport of electrons into the loss cone over an energy range from hundreds of keV to multi‐MeV on diffusive timescales on the order of hours. This process may account for modulation of atmospheric X‐ray fluxes observed from balloons and may constitute a significant loss process for the radiation belts.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079527

4.The Role of Melting Snow in the Ocean Surface Heat Budget

We estimate the cooling flux from snow melting in the ocean through CloudSat satellite snowfall retrievals and reanalysis data. For snowfall events with less then 0.01 mm/h, this flux is inconsequential. Melting snow begins to compete with other ocean surface heat fluxes as snowfall rates increase beyond 0.1 mm/h, and it may often become the dominant heat flux as snowfall rates approach and exceed 1 mm/h. The largest monthly average values of the melting snow cooling flux occur in winter months, approaching‐10 W/m2 in both hemispheres. To determine the regional influence of melting snow on a seasonal basis, we calculate an impact metric that gauges the cooling flux of melting snow against the net flux in the ocean. This metric can be between 20 and 30% in the Northern Hemisphere during MAM, the Southern Ocean during MAM and SON, and in high latitude polar oceans during sea‐ice freeze up seasons.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079182

VI. AGU Blogs

1.The Intersection of Climate Science and Hope: A Personal Story

As a native of the Timbuktu region in Mali, West Africa, one of the most unstable areas of the country, I have been an eyewitness to the devastating effects of climate variability and change on people’s lives. It has been affecting livelihoods, causing migration and hardship, contributing to conflict, and even impeding access to education, among the many impacts. Because of my desire to help my country, I spent my summer interning at Columbia’s Center for International Earth Science Information Network (CIESIN).

https://blogs.agu.org/thefield/2018/09/05/the-intersection-of-climate-science-and-hope-a-personal-story/