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AGU Research Spotlight (Jul 26-Aug 01, 2017)

2017-08-04 10:11:11

I.Climate Change

1. The Competing Climate Effects of Elevation and Albedo

Variations in surface reflectivity are as important as surface elevation changes in determining regional climate at nonpolar latitudes, according to a new modeling study.


2. A Benchmark for Trace Greenhouse Gases in the Arctic Ocean

Samples of seawater from the North American Arctic show that the region is neither a major source nor sink of methane and nitrous oxide to the overlying atmosphere.


3. Airborne Laser Spectroscopy System Can Map Atmospheric Gases

A new versatile spectroscopy system could create ultraprecise maps of Earth’s atmosphere, detect methane emission sources, and scan for chemical weapons.


4. Concepts for Dealing with the Complexity of Weather and Climate

A recent article in Reviews of Geophysics describes how a nonlinear approach and the concept of regimes helps our understanding.


II. Hazards & Disasters

1. Tracking River Flows from Space

Satellite observations, combined with algorithms borrowed from river engineering, could fill large gaps in our knowledge of global river flows where field data are lacking.


2. Storm Model Foresaw Tornado Precursor Hours Before Twister Hit

The experimental Warn-on-Forecast project calculates probabilities of severe weather within at-risk areas smaller than those targeted by current forecasting models.


III. Hydrology, Cryosphere & Earth Surface

1. Follow Earthworm Tracks to Better Simulate Water Flow in Soils

Incorporating paths carved by the critters and by tree roots helps scientists align simulations of tropical soils more closely with real-world data.


2. Small Wetlands Retain Lion’s Share of Nutrients

Still-water ecosystems are key to combating explosive algae growth.


IV.Planetary Sciences

1. A Wealth of Science to Come During Cassini’s Final Orbits

NASA’s spacecraft will continue to unlock Saturn’s mysteries up until the moment it burns up in Saturn’s atmosphere.


2. Could a Newfound Molecule on Titan Be a Building Block for Life?

The discovery of vinyl cyanide in the atmosphere of Saturn’s moon Titan has huge implications for life—but not as we know it.


V.Geophysical Research Letters

1. Robustness of observation-based decadal sea level variability in the Indo-Pacific Ocean

We examine the consistency of Indo-Pacific decadal sea level variability in 10 gridded, observation-based sea level products for the 1960–2010 period. Decadal sea level variations are robust in the Pacific, with more than 50% of variance explained by decadal modulation of two flavors of El Ni?o–Southern Oscillation (classical ENSO and Modoki). Amplitude of decadal sea level variability is weaker in the Indian Ocean than in the Pacific. All data sets indicate a transmission of decadal sea level signals from the western Pacific to the northwest Australian coast through the Indonesian throughflow. The southern tropical Indian Ocean sea level variability is associated with decadal modulations of ENSO in reconstructions but not in reanalyses or in situ data set. The Pacific-independent Indian Ocean decadal sea level variability is not robust but tends to be maximum in the southwestern tropical Indian Ocean. The inconsistency of Indian Ocean decadal variability across the sea level products calls for caution in making definitive conclusions on decadal sea level variability in this basin.


2. Future sea level change from Antarctica's Lambert-Amery glacial system

Future global mean sea level (GMSL) change is dependent on the complex response of the Antarctic ice sheet to ongoing changes and feedbacks in the climate system. The Lambert-Amery glacial system has been observed to be stable over the recent period yet is potentially at risk of rapid grounding line retreat and ice discharge given that a significant volume of its ice is grounded below sea level, making its future contribution to GMSL uncertain. Using a regional ice sheet model of the Lambert-Amery system, we find that under a range of future warming and extreme scenarios, the simulated grounding line remains stable and does not trigger rapid mass loss from grounding line retreat. This allows for increased future accumulation to exceed the mass loss from ice dynamical changes. We suggest that the Lambert-Amery glacial system will remain stable or gain ice mass and mitigate a portion of potential future sea level rise over the next 500 years, with a range of +3.6 to ?117.5 mm GMSL equivalent.


3. Antarctic pack ice algal distribution: Floe-scale spatial variability and predictability from physical parameters

Antarctic pack ice serves as habitat for microalgae which contribute to Southern Ocean primary production and serve as important food source for pelagic herbivores. Ice algal biomass is highly patchy and remains severely undersampled by classical methods such as spatially restricted ice coring surveys. Here we provide an unprecedented view of ice algal biomass distribution, mapped (as chlorophyll a) in a 100 m by 100 m area of a Weddell Sea pack ice floe, using under-ice irradiance measurements taken with an instrumented remotely operated vehicle. We identified significant correlations (p < 0.001) between algal biomass and concomitant in situ surface measurements of snow depth, ice thickness, and estimated sea ice freeboard levels using a statistical model. the model's explanatory power (r2 =" 0.30)" indicates that these parameters alone may provide a first basis for spatial prediction of ice algal biomass, but parameterization of additional determinants is needed to inform more robust upscaling efforts.


4. Aerosol-driven increase in Arctic sea ice over the middle of the twentieth century

Updated observational data sets without climatological infilling show that there was an increase in sea ice concentration in the eastern Arctic between 1950 and 1975, contrary to earlier climatology infilled observational data sets that show weak interannual variations during that time period. We here present climate model simulations showing that this observed sea ice concentration increase was primarily a consequence of cooling induced by increasing anthropogenic aerosols and natural forcing. Indeed, sulphur dioxide emissions, which lead to the formation of sulphate aerosols, peaked around 1980 causing a sharp increase in the burden of sulphate between the 1950s and 1970s; but since 1980, the burden has dropped. Our climate model simulations show that the cooling contribution of aerosols offset the warming effect of increasing greenhouse gases over the midtwentieth century resulting in the expansion of the Arctic sea ice cover. These results challenge the perception that Arctic sea ice extent was unperturbed by human influence until the 1970s, suggesting instead that it exhibited earlier forced multidecadal variations, with implications for our understanding of impacts and adaptation in human and natural Arctic systems.


VI. AGU Blogs

1. The Secret Discoveries Scientist Are Hiding

Thousands of scientists showed up in DC to march for science earlier this year.

Every cancer specialist has the cure for cancer in his desk, and every climate scientist has proof that carbon dioxide is not causing global warming. Oh, and every physicist has a paper showing Einstein’s theory of relativity is all wrong, and I need to come clean as well since I’ve been hiding a method of dissipating hurricanes for 35 years.


2. Bacteria found near abandoned mines could shed light on early Earth

Acidified water draining from abandoned mines, studied primarily as a modern environmental hazard, may offer insight into the oxygenation of Earth’s early atmosphere and development of life on other planets, according to a new study.


3. Freak Summer Nor’easter Headed for the Mid-Atlantic

Gale warnings in July are rare along the mid-Atlantic coast, but if a tropical cyclone is nearby, they do happen. But those are rare, and a gale warning for a nor’easter in late July?




WASHINGTON, DC—The American Geophysical Union (AGU) today announced its 2017 Fellows, an honor given to individual AGU members who have made exceptional scientific contributions and gained prominence in their respective fields of Earth and space sciences. Since the AGU Fellows program was established in 1962, and according to the organization’s bylaws, no more than 0.01 percent of the total membership of AGU is recognized annually. This year’s class of Fellows are geographically diverse coming from 10 countries.



WASHINGTON, DC — The U.S. National Oceanic and Atmospheric Administration’s latestseasonal drought assessment, released on July 20, 2017, finds that since mid-June, drought coverage and intensity increased across the Great Plains and U.S. Southwest, especially in eastern Montana and the Dakotas, exacerbated by periods of intense heat, windy conditions, and low humidity. Drought also increased in southwestern Alaska and on the Big Island of Hawaii.



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