Adjustment time of the first baroclinic Rossby wave in the global oceans

According to the freely linear Rossby wave theory, global 1°×1°climatology of Rossby deformation radius and phase speed are studied under the fiat bottom fluid approximation. Geographical variations in the contours of the phase speed are very similar to those of the Rossby radius of formation, which are mainly affected by stratification, rotation, water depth, topography, etc. The basin-crossing time of the first baroclinic Rossby wave is obtained and analyzed in the global ocean basins. The results are useful to learn the importance of Rosaby wave and the adiabatic adjustment of large-scale ocean circulation.

Fourth Industrial Revolution:Technological Drivers,Impacts and Coping Methods

The world is marching into a new development period when the digital technology,physical technology,and biological technology have achieved an unprecedented development respectively in their own fields,and at the same time their applications are converging greatly.These are the three major technological drivers for the Fourth Industrial Revolution.This paper discusses the specific technology niches of each kind technological driver behind the Fourth Industrial Revolution,and then evaluates impacts of the Fourth Industrial Revolution on global industrial,economic,and social development.At last this paper proposes possible measures and policies for both firms and governments to cope with the changes brought by the Fourth Industrial Revolution.

Water storage changes in North America retrieved from GRACE gravity and GPS data

As global warming continues,the monitoring of changes in terrestrial water storage becomes increasingly important since it plays a critical role in understanding global change and water resource management.In North America as elsewhere in the world,changes in water resources strongly impact agriculture and animal husbandry.From a combination of Gravity Recovery and Climate Experiment（GRACE） gravity and Global Positioning System（GPS） data,it is recently found that water storage from August,2002 to March,2011 recovered after the extreme Canadian Prairies drought between 1999 and 2005.In this paper,we use GRACE monthly gravity data of Release 5 to track the water storage change from August,2002 to June,2014.In Canadian Prairies and the Great Lakes areas,the total water storage is found to have increased during the last decade by a rate of 73.8 ± 14.5 Gt/a,which is larger than that found in the previous study due to the longer time span of GRACE observations used and the reduction of the leakage error.We also find a long term decrease of water storage at a rate of-12.0 ± 4.2 Gt/a in Ungava Peninsula,possibly due to permafrost degradation and less snow accumulation during the winter in the region.In addition,the effect of total mass gain in the surveyed area,on present-day sea level,amounts to-0.18 mm/a,and thus should be taken into account in studies of global sea level change.

Geodynamics of the Calabrian Arc area (Italy) inferred from a dense GNSS network observations

The tectonics and geodynamics of the Calabria region are presented in this study. These are inferred by precise computation of Global Navigation Satellite Systems （GNSS） per~ manent station velocities in a stable Eurasian reference framework. This allowed computation of the coordinates, variance and covariance matrixes, and horizontal and vertical velocities of the 36 permanent sites analyzed, together with the strain rates, and using different techniques. Interesting geodynamic phenomena are presented, including compressional, and deformational fields in the Tyrrhenian coastal sites of Calabria, extensional trends of the Ionian coastal sites, and sliding movement of the Crotone Basin. Conversely, on the northern Tyrrhenian side of the network near the Cilento Park area, the usual extensional tectonic perpendicular to the Apennine chain is observed. The large- scale pattern of the GNSS height velocities is shown, which is characterized by general interesting geodynamic vertical effects that appear to be due to geophysical movement and anthropic activity. Finally, the strain-rate fields computed through three different tech- niques are compared.

From Strategic Ambiguity to Strategic Clarity——Obama Administration’s Global Strategic Adjustments and China-U.S.Relations

Since the end of the Cold War,the United States has turned out to be the sole world superpower and possessed the unmatched power,and its international status and security situation reached the best period in its history.Although the U.S.power has declined relatively,its advantages have not changed substantially.The advantages of the U.S.power determine the essence of the U.S.global strategy,and since the end of the Cold War remains almost intact,which is committed to maintenance of the U.S.hegemony,including 3 core goals:maintaining security,expanding economy and promoting democracy.Since the end of the Cold War,all U.S.presidents have adhered to this hegemonic strategy while making some major adjustments,with some changing expressions and the priorities of the strategic goals.It should be pointed out that there is an important and possibly dangerous trend in the adjustments,,which is the gradual disappearance of strategic flexibility and strategic ambiguity.In other words,these global strategic adjustments after the Cold War have been increasingly focusing on China and the Asia-Pacific region.This trend is likely to continue in the second term of President Obama and will affect the development of China-U.S.relations to a large extent.