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AGU Research Spotlight (Aug 24-Aug 30, 2018)

2018-08-30 10:50:16

I.Climate Change

1.Scientists Meet to Review Preparations for Satellite Launch

In August of last year, more than 300 scientists gathered to make final launch preparations for the latest of the National Oceanic and Atmospheric Administration's (NOAA) polar-orbiting satellites, the Joint Polar Satellite System 1 (JPSS-1). They also focused on calibration/validation (cal/val) of satellite data and derived products from the JPSS series of satellites; the uses of JPSS data for science development; and how to use JPSS data to communicate information about the state of the atmosphere, ocean, cryosphere, and land surface.


2.Heavy Air Pollution May Lower Cognitive Test Scores

A new study found that verbal and math test scores in China dropped with reduced air quality. The effects were especially pronounced for men and elderly populations.


3.New Modeling Framework Improves Radiative Feedback Estimates

A new approach offers insights into the relationship between surface temperature and top-of-atmosphere energy imbalances and improves the understanding of important climate feedbacks.


II.Hazards & Disasters

1.Landslide Database Reveals Uptick in Human-Caused Fatal Slides

Records of nearly 5,000 landslides around the world show that human activities like construction, illegal mining, and hill cutting are increasingly responsible for fatal slides, particularly in Asia.


III.Natural Resources

1.Illegal Seafood Supply Chains Can Now Be Tracked by Satellite

Researchers pinpoint more than 10,000 likely transfers of catches between fishing vessels and cargo ships at sea. Knowing where these transfers occur can help officials crack down on illegal activity.


VI.Science Policy

1.White House Pick for Top Science Spot Stresses Science Integrity

At his Senate confirmation hearing, Kelvin Droegemeier, Trump's choice to head the White House Office of Science and Technology Policy, discussed plans to tackle the nation's scientific challenges.


V.Space & Planets

1.Searching for Signs of Marsquakes

Researchers use high-resolution images of Mars's surface to look for signals of coseismic displacement.


VI.Geophysical Research Letters

1.Vortex Structures in the Wake of an Idealized Seamount in Rotating, Stratified Flow

We present the results of a 3‐D computational model of an idealized seamount in rotating, stratified flow. The emergent vortex structures in the lee of the seamount indicate that the vertical coherence of vortices is strongly dependent on the Coriolis parameter and the background buoyancy frequency. A novel finding from this work is that above a critical Burger number the vortex shedding frequency varies vertically with the local seamount diameter, and adjusts such that the Strouhal number based on the local seamount diameter is consistent with high‐Reynolds number flow past a circular cylinder. This study extends previous literature into a regime exhibiting stronger stratification and rotation, where the transition into vertically‐decoupled eddies occurs. Physically, this transition is associated with the loss of geostrophy in the eddies. The mechanisms governing the transition to vertically‐decoupled vortices may play an important role in the energetics of a seamount interacting with a barotropic flow.


2.Lethargic response to aerosol emissions in current climate models

The global temperature trend observed over the last century is largely the result of two opposing effects – cooling from aerosol particles and greenhouse gas (GHG) warming. While the effect of increasing GHG concentrations on Earth's radiation budget is well‐constrained, that due to anthropogenic aerosols is not, partly due to a lack of observations. However, long‐term surface measurements of changes in downward solar radiation (SDSR), an often‐used proxy for aerosol radiative impact, are available worldwide over the last half‐century. We compare SDSR changes from ~1,400 stations to those from the CMIP5 global climate simulations over the period 1961‐2005. The observed SDSR shows a strong early downward trend followed by a weaker trend‐reversal, broadly consistent with historical aerosol emissions. However, despite considerable changes to known aerosol emissions over time, the models show negligible SDSR trends, revealing a lethargic response to aerosol emissions, and casting doubt on the accuracy of their future climate projections.


3.Surface Creep Rate of the Southern San Andreas Fault Modulated by Stress Perturbations from Nearby Large Events

A major challenge for understanding the physics of shallow fault creep has been to observe and model the long‐term effect of stress changes on creep rate. Here we investigate the surface creep along the southern San Andreas fault (SSAF) using data from interferometric synthetic aperture radar (InSAR) spanning over 25 years (ERS 1992‐1999, ENVISAT 2003‐2010, and Sentinel‐1 2014‐present). The main result of this analysis is that the average surface creep rate increased after the Landers event and then decreased by a factor of 2‐7 over the past few decades. We consider quasi‐static and dynamic Coulomb stress changes on the SSAF due to these three major events. From our analysis, the elevated creep rates after the Landers can only be explained by static stress changes, indicating that even in the presence of dynamically triggered creep, static stress changes may have a long‐lasting effect on SSAF creep rates.


4.Sand mineralogy within the Bagnold Dunes, Gale crater, as observed in situ and from orbit

Curiosity investigated active eolian sands near linear dunes during Phase 2 of the Bagnold‐Dunes campaign in Gale crater, Mars. Ogunquit Beach, a sample scooped from a large‐ripple trough within the Mount Desert Island ripple field and delivered to the CheMin X‐ray diffraction instrument, is dominated by basaltic igneous minerals and X‐ray amorphous materials. CheMin mineralogy of the Gobabeb sample acquired at a large‐ripple crest on the Namib barchan dune during Phase 1 is similar to Ogunquit Beach. Ogunquit Beach, however, contains more plagioclase and Gobabeb contains more olivine. CRISM‐based estimates of mineralogy at the optical surface of Namib Dune and Mount Desert Island demonstrate that surface sands are enriched in olivine and depleted in plagioclase over Mount Desert Island relative to Namib Dune. Differences between CheMin‐derived and CRISM‐derived mineralogies suggest sorting by grain size on bedform‐ to dune‐field‐scales. Crystal chemistry from CheMin suggests contributions from multiple igneous sources and the local bedrock.



1.Art asks questions, science seeks answers

Science and art are deeply related. Both involve looking hard at what is around us: taking time to observe and collect information to filter through brains. Art asks questions, science seeks answers.

I have been drawing and painting since I was a child. I studied art in college and took it with me everywhere afterward. In 2009 I moved to a small city in northern Minnesota to focus more closely on painting. I have generally painted about things that interest me: environmentalism, technology, and humanity. I am thrilled to have an opportunity to work on paintings where all three of these interests mingle.


2.Scientists find corals in deeper waters under stress too

Coral reefs around the world are threatened by warming ocean temperatures, a major driver of coral bleaching. Scientists routinely use sea-surface temperature data collected by satellites to predict the temperature-driven stress on reef communities, but new research shows that surface measurements alone may not accurately predict the full extent of thermal stress on deeper corals.A new study led by scientists at Scripps Institution of Oceanography at the University of California San Diego and the Coral Reef Research Foundation (CRRF) in Palau describes a novel approach for predicting warm temperature-induced stress on corals from the sea surface through a deeper expanse ranging from 30-150 meters (100-500 feet) known as the mesophotic zone.



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