I. Climate Change
1. Snowfall Rates from Satellite Data Help Weather Forecasters
A new data product calculates snowfall rates from weather data beamed directly from several satellites, helping meteorologists provide fast, accurate weather reports and forecasts.
https://eos.org/project-updates/snowfall-rates-from-satellite-data-help-weather-forecasters
2. Diagnosing the Warm Bias in the Central United States
A set of four papers published in JGR: Atmospheres present results from a project investigating why models predict warmer surface temperatures than are observed in the central United States.
https://eos.org/editors-vox/diagnosing-the-warm-bias-in-the-central-united-states
3. Fossilized Caribbean Corals Reveal Ancient Summer Rains
Isotope records and climate modeling suggest that the rainy Intertropical Convergence Zone expanded northward into the southern Caribbean during a warm interglacial period about 125,000 years ago.
https://eos.org/research-spotlights/fossilized-caribbean-corals-reveal-ancient-summer-rains
II. Planetary Sciences
1. Evidence of Extensive Ice Deposits Near Mercury’s South Pole
New radar observations and refined illumination maps reveal uneven water ice deposits twice the size of those found around the planet’s north pole, suggesting the source may be a recent comet impact.
https://eos.org/research-spotlights/evidence-of-extensive-ice-deposits-near-mercurys-south-pole
III. Biogeosciences
Defining the chemical relationships between water, sediment, and organisms that thrive beneath riverbeds.
https://eos.org/research-spotlights/life-in-the-hyporheic-zone
2. Drones Hunt for Impacts of Oil Exploration on Wetland Emissions
Seismic lines, constructed for petroleum resource exploration, disturb Canadian peatlands, but how can we detect their impact on greenhouse gas budgets?
https://eos.org/editor-highlights/drones-hunt-for-impacts-of-oil-exploration-on-wetland-emissions
IV. Geology & Geophysics
1. Earth Day Message from an Astronaut on the Space Station
NASA astronaut and geoscientist Drew Feustel reminds us: High above Earth, you see no borders; you barely see cities. You do see evidence of Earth’s raw power.
https://eos.org/opinions/earth-day-message-from-an-astronaut-on-the-space-station
V. Science Policy & Funding
1. Senate OK’s New NASA Head by Razor-Thin Margin
Bridenstine, the first politician to lead the agency, is urged to run NASA in a nonpartisan manner and to support its science missions.
https://eos.org/articles/senate-oks-new-nasa-head-by-razor-thin-margin
2. Snapshots of March for Science Signs Across the Globe
From chemical puns and censorship to the spectrum of awesome and a touch of magic, signs at this year’s events showcased the science marchers’ creativity and passion…and a bit of humor.
https://eos.org/articles/snapshots-of-march-for-science-signs-across-the-globe
VI. Geophysical Research Letters
This study developed a submesoscale eddy‐resolving oceanic dispersal modeling system comprising a double‐nested oceanic downscaling model and an offline oceanic radionuclide dispersion model. This was used to investigate the influences of submesoscale coherent structures (SCSs) and associated ageostrophic secondary circulations (ASCs) on the three‐dimensional (3‐D) dispersal of dissolved cesium‐137 (137Cs) released from the Fukushima Daiichi Nuclear Power Plant (FNPP1). Extensive model‐data comparison demonstrated that the innermost high‐resolution model, with a lateral grid resolution of 1 km, could successfully reproduce transient mesoscale oceanic structures, the Kuroshio path and stratification, and spatiotemporal variations of 137Cs concentrations.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JC013359
2. The Deep Western Boundary Current in the Labrador Sea From Observations and a High‐Resolution Model
Long‐term observations from a 17 year long mooring array at the exit of the Labrador Sea at 53°N are compared to the output of a high‐resolution model (VIKING20). Both are analyzed to define robust integral properties on basin and regional scale, which can be determined and evaluated equally well. While both, the observations and the model, show a narrow DWBC cyclonically engulfing the Labrador Sea, the model's boundary current system is more barotropic than in the observations and spectral analysis indicates stronger monthly to interannual transport variability. Compared to the model, the observations show a stronger density gradient, hence a stronger baroclinicity, from center to boundary.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JC013702
The descent of the Denmark Strait overflow plume is an important process in the Atlantic Meridional Overturning Circulation. Downstream of the sill, the plume entrains ambient water, increasing its volume transport. The entrainment and related transfer of energy can be driven by vertical or horizontal turbulent mixing, and varies spatially, as the plume descends, and temporally, as the volume transport at the sill changes. Using over 30 years of profile data, this spatial and temporal variability in the first 200 km downstream of the sill was investigated.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2018JC013821
We applied ocean color algorithms and a primary production model to a 13‐year ocean color data set to assess interannual variations of Changjiang‐influenced water (CIW) dispersion, with an emphasis on the unusual CIW dispersion during July 2010. The characteristics of the CIW offshore dispersion were primarily driven by alongshore winds and secondarily by the Changjiang discharge, the interannual variations of which were linked to the El Niño/La Niña. The unusual southeastward dispersion of CIW in July 2010 was attributed to a relatively weak southwesterly wind (with southwesterly wind anomalies) and high Changjiang discharge (after the El Niño peak in winter). In July 2010, the CIW, which is characterized by low‐salinity, high‐gelbstoff, and high‐primary production, intruded into the Kuroshio Current axis to form a rare band of CIW that flowed toward an area south of Japan. The southeastward dispersion of CIW in July 2003 was also unusual, but it did not extend as far as in July 2010, perhaps because of the relatively strong southwesterly winds and low Changjiang discharge in July 2003. During La Niña events, the dispersion of CIW retreated toward the coast due to prevailing northeasterly wind anomalies. We confirmed that the CIW in July 2010 was characterized by low‐salinity, abundant phytoplankton biomass, and high biological production. The fact that high biological production and the peak of Changjiang discharge occurred in the same month (July) in 2010 indicated that biogeochemical production stimulated by nutrients from the Changjiang was higher than during normal summer conditions.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JC013319
Using the unprecedented 7 year monitoring of sea surface salinity (SSS) from the Soil Moisture Ocean Salinity (SMOS) satellite mission, an unexpected large‐scale anomaly at 20°N is studied in the tropical Pacific Ocean following the 2015‐2016 extreme El Niño event. This basin‐wide negative anomaly (below −0.3) is present in October 2015 between 15 and 25°N, reaching the Hawaiian archipelago. It has not been previously observed during El Niño events. It is accompanied by a negative equatorial SSS anomaly at the dateline (below −0.5) which has been previously described as an El Niño‐associated SSS anomaly. A wide range of observations (in situ and space‐borne) and a state‐of‐the‐art ocean model simulation are used together to characterize and understand the mechanisms leading to this singular SSS signal. The extra‐equatorial negative SSS anomaly is found to be a superposition of a persisting SSS anomaly due to the 2014 weak El Niño and of the larger 2015‐2016 El Niño SSS anomaly. Both were advected northward in the tropical current system by the mean Ekman currents and hypothetically by instabilities in the zonal currents patterns. An analysis of analogous structures in the past 20 years shows that this northward displacement of SSS anomalies is not El Niño specific, even if their advection is enhanced during El Niño events. This study shows that when surface freshwater fluxes are weak SSS, unlike sea surface temperature, can be used to trace water mass displacement for up to 20 months.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JC013423
6. New Evidence of Breakpoint Forced Long Waves: Laboratory, Numerical, and Field Observations
Numerical modeling and analysis of laboratory and field data are combined to show new evidence of breakpoint forced long waves. The laboratory data and numerical modeling show that the breakpoint can oscillate at frequencies not directly linked to the wave group envelope for specific bichromatic wave groups. The breakpoint therefore oscillates at frequencies where incident bound long waves are not present, enabling direct identification of breakpoint forced waves. Spectral analysis and cross‐shore wave propagation patterns indicate that the breakpoint forced waves occur at subharmonic wave groups frequencies, the repeat frequency of the short waves within the group, and at frequencies associated with triad interactions. The results indicate that in this case the long waves are generated by breakpoint forcing rather than by energy transfer during shoaling of the incident waves. The slowly varying shape of the short waves in the groups and wave merging at the breakpoint controls the modulation of the breakpoint in these cases. The spectral analysis is applied to two field data sets where the breakpoint oscillation, incident waves and shoreline oscillation were measured, and infragravity wave generation is again identified at discrete frequencies that are not present in the incident wave group envelope, with merging of waves at the breakpoint again evident. The magnitudes of the generated infragravity waves outside the surf zone are also dependent on the normalized surf zone width. Both sets of observations provide further evidence for the generation of infragravity waves by the breakpoint forcing mechanism in the field.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JC013621
VII. AGU Blogs
1. Boulder meets house: the power of landslides
Boulder meets house: a video was posted on Youtube last week that dramatically illustrates the power of landslides. The limited accompanying text indicates that it was shot on the NH1A road between Udhampur and Srinigar in northern India, at Peerah. This location is easily identified on Google Earth – it appears to be hilly terrain with plenty of evidence of landslides.
https://blogs.agu.org/landslideblog/2018/04/24/boulder-meets-house/
2. Building better tools for risk communication with user-centered design
How can we build better tools to communicate about coastal risks? As a technical communicator, I’m interested in how we can make scientific information more understandable and meaningful for different audiences. One of the things I study is how interactive risk visualization tools are made. That is, I study how these tools are developed: who does the design and development, what choices they make about design and content, and how audiences or end-users are (or aren’t) involved throughout the process.
https://blogs.agu.org/sciencecommunication/2018/04/23/building-better-tools-for-risk-communication-with-user-centered-design/
3. The Sucun rockslide in Lishui, China in 2016
The Sucun rockslide (also known as the Su Village rockslide) killed 27 people in Lishui, Zhejiang in China on 28th September 2016. Apart from the significant losses, this was a notable landslide for the fact that it was caught on video from two different perspectives.
https://blogs.agu.org/landslideblog/2018/04/23/sucun-rockslide-1/
4. Lago Cholila, Argentina Headwaters Glacier Retreat Lake Formation
Glaciers form the headwaters for Lago Cholila which drains into Futaleufu River in west central Argentina . Davies and Glasser (2012) mapped the glaciers in the Hornopiren region just to the northwest and Parque Nacionale. Corcovado just to the southwest finding a 13-15 % area loss from 1986 to 2011. Here we examine the changes of four of the glaciers in Landsat images from 1987-2017.
https://blogs.agu.org/fromaglaciersperspective/2018/04/20/lago-cholila-argentina-headwaters-glacier-retreat-lake-formation/
5. Further information about the Castell de Mur landslide in Spain
Over the last couple of days more information has emerged about the Castell de Mur landslide in Spain, which killed two people earlier this week. My friends at UPC, Jordi Corominas and Marcel Hurlimann and colleagues have provided two drone images of the landslide, which I post here with their permission. This image shows the rear scarp of the landslide.
https://blogs.agu.org/landslideblog/2018/04/20/castell-de-mur-2/
