AGU期刊一周Research Spotlight (March 24~ March 30, 2017)

发布时间:2017-3-31 9:00:21 点击次数:429

I. Atmospheric Sciences

1. New Data Buoys Watch Typhoons from Within the Storm

Advanced real-time data buoys have observed nine strong typhoons in the northwestern Pacific Ocean since 2015, providing high-resolution data and reducing the uncertainty of numerical model forecasts.

https://eos.org/project-updates/new-data-buoys-watch-typhoons-from-within-the-storm

2. Satellite Data Reveal Effects of Aerosols in Earth's Atmosphere

Combining data from multiple sources could aid in predicting the tiny atmospheric particles' effects on global warming.

https://eos.org/research-spotlights/satellite-data-reveal-effects-of-aerosols-in-earths-atmosphere


II. Science Policy

1. White House Issues Sweeping Executive Order on Energy, Climate

Supporters praised the order, but environmental groups said it ignores climate threats, puts public health at risk, and undermines the economy.

https://eos.org/articles/white-house-issues-sweeping-executive-order-on-energy-climate


III. Hydrology, Cryosphere & Earth Surface

1. Mapping the Topographic Fingerprints of Humanity Across Earth

If increasingly globalized societies are to make better land management decisions, the geosciences must globally evaluate how humans are reshaping Earth's surface

https://eos.org/opinions/mapping-the-topographic-fingerprints-of-humanity-across-earth


IV. Hazards & Disasters

1. Neotectonics and Earthquake Forecasting

The editors of a new book describe the evolution of major earthquake producing fault zones in the eastern Mediterranean region and explore how earthquake forecasting could improve.

https://eos.org/editors-vox/neotectonics-and-earthquake-forecasting

2. Commercial Underwater Cable Systems Could Reduce Disaster Impact

Workshop on SMART Cable Applications in Earthquake and Tsunami Science and Early Warning; Potsdam, Germany, 3–4 November 2016

https://eos.org/meeting-reports/commercial-underwater-cable-systems-could-reduce-disaster-impact


V. Ocean Sciences

1. New Study Models Shoreline Change in Southern California

Future predictions indicate nearly all the beaches in southern California will experience erosion due to accelerated sea-level rise.

https://eos.org/scientific-press/new-study-models-shoreline-change-in-southern-california


VI. Climate Change

1. White House Mum on Arctic Priorities as Key Meeting Approaches

Arctic experts are watching to see whether U.S. Secretary of State Rex Tillerson will attend the Arctic Council meeting in May as a sign of how engaged the Trump administration will be in the region.

https://eos.org/articles/white-house-mum-on-arctic-priorities-as-key-meeting-approaches


VII. Natural Resources

1. Global Drought Clustering Could Mean Big Losses for Mining

Long-term climate records could help mining companies and their investors assess the financial risk of water shortages.

https://eos.org/research-spotlights/global-drought-clustering-could-mean-big-losses-for-mining


VIII. Geophysical Research Letters

1. Seismogenic width controls aspect ratios of earthquake ruptures

We investigate the effect of seismogenic width on aspect ratios of earthquake ruptures by using numerical simulations of strike-slip faulting and an energy balance criterion near rupture tips. If the seismogenic width is smaller than a critical value, then ruptures cannot break the entire fault, regardless of the size of the nucleation zone. The seismic moments of these self-arresting ruptures increase with the nucleation size, forming nucleation-related events. The aspect ratios increase with the seismogenic width but are smaller than 8. In contrast, ruptures become breakaway and tend to have high aspect ratios (>8) if the seismogenic width is sufficiently large. But the critical nucleation size is larger than the theoretical estimate for an unbounded fault. The eventual seismic moments of breakaway ruptures do not depend on the nucleation size. Our results suggest that estimating final earthquake magnitude from the nucleation phase may only be plausible on faults with small seismogenic width.

http://onlinelibrary.wiley.com/doi/10.1002/2016GL072168/full

2. The complex behavior of El Niño winter 2015–2016

This paper examines the outstanding characteristics of the strong 2015–2016 El Niño (EN) winter and its impact over the European region through the stratosphere. Despite being classified as a strong eastern Pacific (EP) EN event, our analysis reveals an anomalous behavior, with some signatures that are more typical of central Pacific (CP) EN events instead. They include (i) a record-breaking value of the CP index, (ii) a stronger polar vortex in early and midwinter, due to reduced upward wave activity and a weakened Aleutian low, and (iii) the occurrence of one of the earliest stratospheric final warmings (SFWs) on record, which are more prone to occur during CP-EN. Following the SFW, a stratospheric influence on the Euro-Atlantic sector is reported in spring, with persistent Greenland blocking resulting in extreme precipitation over some southern European regions. Results highlight the importance of considering early SFWs as mediators of El Niño teleconnections.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL072920/full

3.Precipitation-driven glacier changes in the Pamir and Hindu Kush mountains

Glaciers in the Pamir-Hindu Kush-Karakoram appear to be less influenced by global warming and have instead experienced slight gains in mass, unlike most other glaciers around the world. Here we apply laser altimetry and satellite-derived precipitation products to characterize the relationship between the glaciers and precipitation. We found a strong correlation (r ≥ 0.92, p < 0.005) between the year-to-year changes in glacier thickness and precipitation in the Pamir and Hindu Kush from 2003 to 2008, indicating the primary role of precipitation in the glacier changes. The amount of precipitation in the glacial region is underestimated by approximately 7 ± 2 times in the gridded precipitation product. This underestimation is attributed to the low resolution and lack of orographic precipitation in the gridded products. The long-term precipitation data show strong interannual variations, which probably cause similar variations in glaciers and biases in previous glacier mass change estimates.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL072646/full

4. Chorus whistler wave source scales as determined from multipoint Van Allen Probe measurements

Whistler mode chorus waves are particularly important in outer radiation belt dynamics due to their key role in controlling the acceleration and scattering of electrons over a very wide energy range. The key parameters for both nonlinear and quasi-linear treatment of wave-particle interactions are the temporal and spatial scales of the wave source region and coherence of the wave field perturbations. Neither the source scale nor the coherence scale is well established experimentally, mostly because of a lack of multipoint VLF waveform measurements. We present an unprecedentedly long interval of coordinated VLF waveform measurements (sampled at 16384 s−1) aboard the two Van Allen Probes spacecraft—9 h (0800–1200 UT and 1700–2200 UT) during two consecutive apogees on 15 July 2014. The spacecraft separations varied from about 100 to 5000 km (mostly radially); measurements covered an L shell range from 3 to 6; magnetic local time 0430–0900, and magnetic latitudes were ~15 and ~5° during the two orbits. Using time-domain correlation techniques, the single chorus source spatial extent transverse to the background magnetic field has been determined to be about 550–650 km for upper band chorus waves with amplitudes less than 100 pT and up to 800 km for larger amplitude, lower band chorus waves. The ratio between wave amplitudes measured on the two spacecraft is also examined to reveal that the wave amplitude distribution within a single chorus element generation area can be well approximated by a Gaussian exp(−0.5 • r2/r02), with the characteristic scale r0around 300 km. Waves detected by the two spacecraft were found to be coherent in phase at distances up to 400 km.

http://onlinelibrary.wiley.com/doi/10.1002/2017GL072701/full

5. The projected demise of Barnes Ice Cap: Evidence of an unusually warm 21st century Arctic

As a remnant of the Laurentide Ice Sheet, Barnes Ice Cap owes its existence and present form in part to the climate of the last glacial period. The ice cap has been sustained in the present interglacial climate by its own topography through the mass balance-elevation feedback. A coupled mass balance and ice-flow model, forced by Coupled Model Intercomparison Project Phase 5 climate model output, projects that the current ice cap will likely disappear in the next 300 years. For greenhouse gas Representative Concentration Pathways of +2.6 to +8.5 Wm−2, the projected ice-cap survival times range from 150 to 530 years. Measured concentrations of cosmogenic radionuclides 10Be, 26Al, and 14C at sites exposed near the ice-cap margin suggest the pending disappearance of Barnes Ice Cap is very unusual in the last million years. The data and models together point to an exceptionally warm 21st century Arctic climate.

http://onlinelibrary.wiley.com/doi/10.1002/2016GL072394/full

6. The projected demise of Barnes Ice Cap: Evidence of an unusually warm 21st century Arctic

As a remnant of the Laurentide Ice Sheet, Barnes Ice Cap owes its existence and present form in part to the climate of the last glacial period. The ice cap has been sustained in the present interglacial climate by its own topography through the mass balance-elevation feedback. A coupled mass balance and ice-flow model, forced by Coupled Model Intercomparison Project Phase 5 climate model output, projects that the current ice cap will likely disappear in the next 300 years. For greenhouse gas Representative Concentration Pathways of +2.6 to +8.5 Wm−2, the projected ice-cap survival times range from 150 to 530 years. Measured concentrations of cosmogenic radionuclides 10Be, 26Al, and 14C at sites exposed near the ice-cap margin suggest the pending disappearance of Barnes Ice Cap is very unusual in the last million years. The data and models together point to an exceptionally warm 21st century Arctic climate.

http://onlinelibrary.wiley.com/doi/10.1002/2016GL072394/full


IX. AGU Blogs

1. Study shows as US drilling surged, methane emissions didn’t

A new study shows U.S. methane emissions did not grow significantly from 2000 to 2013 and are not likely to have been an important driver of the increase in atmospheric methane levels observed worldwide after 2007, as other studies have suggested. The new study provides additional insight into a question that has puzzled scientists for the past decade: what has been causing the increase in global methane levels since 2007?

http://blogs.agu.org/geospace/2017/03/24/study-shows-us-drilling-surged-methane-emissions-didnt/

2. The Fake Climate Debate and The Real One

I just finished reading a paper by Michael Mann, Stefan Rahmstorf et.al in Nature Reports today that is getting some deserved press attention. It’s rather complicated (OK, for non-atmospheric science geeks, it’s a brick) but in plain language, it indicates that the warming of the climate is doing what many of my fellow forecasters have been suspecting for quite some time: changing the upper-level wind flow and therefore changing our …

http://blogs.agu.org/wildwildscience/2017/03/28/fake-climate-debate-real-one/

3. Look Up and Say Hello to Altocumulus Asperitus and Cirrus Homogenitus

It was Luke Howard, a Fellow of the Royal Society, who first gave us the cloud names like cirrus, stratus, and cumulus (that we still use today), and that was way back in 1802! This is important because to understand something, you first have to observe and classify it, and this is true of all science, not just meteorology. So, it’s big news when we add some new cloud names, and if …

http://blogs.agu.org/wildwildscience/2017/03/25/look-say-hello-altocumulus-asperitus-cirrus-homogenitus/

4. Sea Ice and China Smog

Even Antarctica saw record low ice area during their summer (boreal winter), but there’s new research that seems to show a link between the Arctic ice loss and increased air pollution in China. With dark, heat-absorbing water now replacing what was once bright and very reflective ice, the energy balance of the atmosphere has to change, and that change translates to changing weather patterns. There is quite a bit of research into this now, …

http://blogs.agu.org/wildwildscience/2017/03/23/sea-ice-china-smog/