AGU期刊一周Research Spotlight (Feb 9~Feb 16, 2017)

发布时间:2017-2-17 8:48:39 点击次数:422

I. Atmospheric Sciences

1. NOAA Video Shows Satellite Views of Louisiana Tornadoes

Real-time updates of storms will help forecasters track and predict where the most damage could occur.

II. Science Policy

1. EPA Comes Under the Gun in Congressional Hearing

The hearing also examined a complaint that a former NOAA scientist manipulated data in a high-profile global warming paper.

III. Hydrology, Cryosphere & Earth Surface

1. How Climate Change Affects the Flow of Carbon from Land to Sea

Changes in precipitation and runoff in New England may be driving more dissolved organic carbon into the Gulf of Maine.

IV. Geochemistry, Mineralogy, Volcanology

1. Fingerprinting the Source of Fore-Arc Fluids

A new model tracks boron and other tracers in fluids expelled from subducting slabs to help identify the fluids' source regions and migration routes.

V. Ocean Sciences

1. Swirling Eddies in the Antarctic May Have Global Impacts

A new model examines how eddies in the Antarctic Circumpolar Current effect volume transport of the world's strongest current.

VI. Geophysical Research Letters

1. EMIC wave scale size in the inner magnetosphere: Observations from the dual Van Allen Probes

Estimating the spatial scales of electromagnetic ion cyclotron (EMIC) waves is critical for quantifying their overall scattering efficiency and effects on thermal plasma, ring current, and radiation belt particles. Using measurements from the dual Van Allen Probes in 2013–2014, we characterize the spatial and temporal extents of regions of EMIC wave activity and how these depend on local time and radial distance within the inner magnetosphere. Observations are categorized into three types—waves observed by only one spacecraft, waves measured by both spacecraft simultaneously, and waves observed by both spacecraft with some time lag. Analysis reveals that dayside (and H+ band) EMIC waves more frequently span larger spatial areas, while nightside (and He+ band) waves are more often localized but can persist many hours. These investigations give insight into the nature of EMIC wave generation and support more accurate quantification of their effects on the ring current and outer radiation belt.

2. Observed strengthening of interbasin exchange via the Indonesian seas due to rainfall intensification

A proxy of the Indonesian Throughflow (ITF) transport, developed using in situ hydrographic measurements along with assimilations, shows a significant strengthening trend during the past decade. This trend is due to a freshening and subsequent increase in the halosteric component of the ITF transport associated with enhanced rainfall over the Maritime Continent over the same period. The strengthening of the ITF transport leads to a significant change in heat and freshwater exchange between the Pacific and Indian Oceans and contributes to the warming and freshening of the eastern Indian Ocean. The combined effect of the ITF transport of mass and freshwater along with tropical rainfall plays a very important role in the climate system.

3. Gyre-scale deep convection in the subpolar North Atlantic Ocean during winter 2014–2015

Using Argo floats, we show that a major deep convective activity occurred simultaneously in the Labrador Sea (LAB), south of Cape Farewell (SCF), and the Irminger Sea (IRM) during winter 2014–2015. Convection was driven by exceptional heat loss to the atmosphere (up to 50% higher than the climatological mean). This is the first observation of deep convection over such a widespread area. Mixed layer depths exceptionally reached 1700 m in SCF and 1400 m in IRM. The deep thermocline density gradient limited the mixed layer deepening in the Labrador Sea to 1800 m. Potential densities of deep waters were similar in the three basins (27.73–27.74 kg m−3) but warmer by 0.3°C and saltier by 0.04 in IRM than in LAB and SCF, meaning that each basin formed locally its own deep water. The cold anomaly that developed recently in the North Atlantic Ocean favored and was enhanced by this exceptional convection.

4. Common climatic signal from glaciers in the European Alps over the last 50 years

Conventional glacier-wide mass balances are commonly used to study the effect of climate forcing on glacier melt. Unfortunately, the glacier-wide mass balances are also influenced by the glacier's dynamic response. Investigations on the effects of climate forcing on glaciers can be largely improved by analyzing point mass balances. Using a statistical model, we have found that 52% of the year-to-year deviations in the point mass balances of six glaciers distributed across the entire European Alps can be attributed to a common variability. Point mass balance changes reveal remarkable regional consistencies reaching 80% for glaciers less than 10 km apart. Compared to the steady state conditions of the 1962–1982 period, the surface mass balance changes are −0.85 m water equivalent (w.e.) a−1 for 1983–2002 and −1.63 m w.e. a−1for 2003–2013. This indicates a clear and regionally consistent acceleration of mass loss over recent decades over the entire European Alps.

5. Further intensification of deep convection in the Labrador Sea in 2016

There has been a progressive deepening of winter convection in the Labrador Sea since 2012, with the individual profile maximum depth exceeding 1800 m since 2014 and reaching 2100 m in 2016. This increase, during repeated positive phases of the winter North Atlantic Oscillation (NAO), resembles that during the formation of the record depth (2500 m) Labrador Sea Water (LSW) class in 1987–1994, attributed to repeated positive NAO forcing having provided critical preconditioning. The 2012–2016 LSW class is one of the deepest and most persistent ever observed (back to 1938). Year-round observations from profiling Argo floats since 2002 complemented by annual surveys are providing novel information on the seasonal-to-decadal evolution of LSW, such as its variable density, the recent multiyear preconditioning, and its 2016 density being the highest since the mid-1990s. These findings should help international observation programs and numerical model studies investigating LSW influences on the subpolar North Atlantic and Atlantic Meridional Overturning Circulation.

6. Concentric traveling ionosphere disturbances triggered by Super Typhoon Meranti (2016)

Concentric traveling ionosphere disturbances (CTIDs) in total electron content triggered by Super Typhoon Meranti on 13 September 2016 are detected by using the ground-based Global Navigation Satellite Systems network in Taiwan. The CTIDs emanated outward before the typhoon landfall and lasted for more than 10 h. The characteristics of CTIDs agree with the gravity wave theory and exhibit spatial and temporal scales in wave periods of ~8–30 min, horizontal wavelengths of ~160–200 km, and horizontal phase velocities of ~106–220 m/s. We also observe the CTIDs showing the stationary wave character. Broad spectra of CTIDs are excited after the rainbands of typhoon impinged on Central Mountain Range of Taiwan. The ray-tracing technique confirms that the CTIDs were excited by convective clouds, spiral rainbands, and the eyewall of Typhoon Meranti. This study provides new evidence of typhoon-induced concentric gravity waves in the ionosphere.


1. Daily disturbance from upper atmosphere leaves its footprints on tropical rainfall

A team of scientists led by postdoctoral researcher Takatoshi Sakazaki, from the University of Hawaiʻi at Mānoa’s International Pacific Research Center (IPRC), has analyzed satellite-based observations and computer model simulations of tropical rainfall variation throughout the day in an effort to determine the root cause of the temporal patterns. Their results, accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union, show that daily tropical rainfall distribution is significantly shaped by heating of the upper atmosphere.

2. New GOES-16 Weather Satellite Sees Monday’s Low Pressure Bomb

I wrote yesterday about the storm that exploded off the coast of the Mid-Atlantic on Monday, and now you can see it develop from GOES-16. This animation was released today of the storm exploding as it moved out to sea. This explosive cyclogenesis produced hurricane force winds in the Atlantic, and winds over 50 mph on the coast from Maryland to Boston. This view is one of the three water vapour …

3. Astonishing February Heat From Colorado to Oklahoma, and Into The High Arctic

Denver reached 80 degrees Friday, smashing their record high for the 10th of February by 9 degrees, but wait, there’s more. They also saw their hottest February temperature on record, and records there go back to 1872! Grant was President of the U.S. when temperature records began in Denver. Colorado Springs, and Pueblo, also saw their hottest February day on record. The heat shifted south into Oklahoma today and Oklahoma City smashed their …

4. GOES-R Solar Instruments are Working!

The GOES-R (now GOES-16) instruments continue to be checked out and calibrated. This from, NASA today: On January 21, 2017, the GOES-16 Extreme Ultraviolet and X-Ray Irradiance Sensors (EXIS) observed solar flares.  Credits: NOAA/NASA Solar flares are huge eruptions of energy on the sun and often produce clouds of plasma traveling more than a million miles an hour.  When these clouds reach Earth they can cause radio communications blackouts, disruptions …