Multidecadal seesaw in cold wave frequency between central Eurasia and Greenland and its relation to the Atlantic Multidecadal Oscillation

2021 ◽  
Author(s):  
Yusen Liu ◽  
Cheng Sun ◽  
Zhanqiu Gong ◽  
Jianping Li ◽  
Zhen Shi
2020 ◽  
Vol 650 ◽  
pp. 269-287
Author(s):  
WC Thaxton ◽  
JC Taylor ◽  
RG Asch

As the effects of climate change become more pronounced, variation in the direction and magnitude of shifts in species occurrence in space and time may disrupt interspecific interactions in ecological communities. In this study, we examined how the fall and winter ichthyoplankton community in the Newport River Estuary located inshore of Pamlico Sound in the southeastern United States has responded to environmental variability over the last 27 yr. We relate the timing of estuarine ingress of 10 larval fish species to changes in sea surface temperature (SST), the Atlantic Multidecadal Oscillation, the North Atlantic Oscillation, wind strength and phenology, and tidal height. We also examined whether any species exhibited trends in ingress phenology over the last 3 decades. Species varied in the magnitude of their responses to all of the environmental variables studied, but most shared a common direction of change. SST and northerly wind strength had the largest impact on estuarine ingress phenology, with most species ingressing earlier during warm years and delaying ingress during years with strong northerly winds. As SST warms in the coming decades, the average date of ingress of some species (Atlantic croaker Micropogonias undulatus, summer flounder Paralichthys dentatus, pinfish Lagodon rhomboides) is projected to advance on the order of weeks to months, assuming temperatures do not exceed a threshold at which species can no longer respond through changes in phenology. These shifts in ingress could affect larval survival and growth since environmental conditions in the estuarine and pelagic nursery habitats of fishes also vary seasonally.


2020 ◽  
Vol 54 (4) ◽  
pp. 403-431
Author(s):  
Bulat R. Rakhimzianov

Abstract This article explores relations between Muscovy and the so-called Later Golden Horde successor states that existed during the fifteenth and sixteenth centuries on the territory of Desht-i Qipchaq (the Qipchaq Steppe, a part of the East European steppe bounded roughly by the Oskol and Tobol rivers, the steppe-forest line, and the Caspian and Aral Seas). As a part of, and later a successor to, the Juchid ulus (also known as the Golden Horde), Muscovy adopted a number of its political and social institutions. The most crucial events in the almost six-century-long history of relations between Muscovy and the Tatars (13–18th centuries) were the Mongol invasion of the Northern, Eastern and parts of the Southern Rus’ principalities between 1237 and 1241, and the Muscovite annexation of the Kazan and Astrakhan khanates between 1552 and 1556. According to the model proposed here, the Tatars began as the dominant partner in these mutual relations; however, from the beginning of the seventeenth century this role was gradually inverted. Indicators of a change in the relationship between the Muscovite grand principality and the Golden Horde can be found in the diplomatic contacts between Muscovy and the Tatar khanates. The main goal of the article is to reveal the changing position of Muscovy within the system of the Later Golden Horde successor states. An additional goal is to revisit the role of the Tatar khanates in the political history of Central Eurasia in the fifteenth and sixteenth centuries.


2021 ◽  
pp. 1-10
Author(s):  
Zhiyue Zhao ◽  
Ning Zhao ◽  
Lide Fang ◽  
Xiaoting Li

During the long-distance transportation of wet-gas, the dominant frequency is of great significance for the study of pipeline fatigue and damage, and the safety production. Therefore, the theoretical and experimental researches for dominant frequency are carried out increasingly. However, most of the current prediction correlation of dominant frequency are mainly applicable to atmospheric pressure conditions (0.1 MPa), and the prediction accuracy is not accurate enough. The paper obtains the time series signal of liquid film thickness by near-infrared (NIR) sensor, and then calculates the wave frequency by the power spectrum density (PSD). The performance of typical predictive correlation is evaluated and analyzed by utilizing the experimental data at different flow and pressure conditions (0.1–0.8) MPa. The structure of Strouhal number and Lockhart-Martinelli (L-M) parameter are optimized reasonably, the mean velocity of the liquid film surface, the density increment of gas core, the gas core mass flow and average liquid film velocity are considered in the L-M parameter, a modified interfacial wave frequency correlation is proposed. The results indicate that the mean absolute error of the predictive correlation is 9.06% (current data) and 25.64% (literature data). The new correlation has a better predictive accuracy.


2021 ◽  
Vol 534 ◽  
pp. 168046
Author(s):  
Zhen-wei Zhou ◽  
Xi-guang Wang ◽  
Yao-zhuang Nie ◽  
Qing-lin Xia ◽  
Guang-hua Guo

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