Submesoscale Vorticity and Divergence in the Alboran Sea: Scale and Depth Dependence

The statistics of submesoscale divergence and vorticity (kinematic properties, KPs) in the Alboran Sea (Mediterranean Sea) are investigated, using data from drifters released during two experiments in June 2018 and April 2019 in the framework of the Coherent Lagrangian Pathways from the Surface Ocean to Interior (CALYPSO) project. Surface drifters sampling the first meter of water (CARTHE and CODE) and 15 m drifters (SVP) are considered. The area of interest is dominated by processes of strong frontogenesis and eddy formation as well as mixing, related to the high lateral gradients between Mediterranean and Atlantic waters. Drifter coverage and distribution allow to investigate the dependence of KPs on horizontal scales in a range between 1 and 16 km, that effectively bridges submesoscale and mesoscale processes, and at two depths, of 1 and 15 m. For both experiments, the surface flow is highly ageostrophic at 1 km scale, with positive vorticity skewness indicating the presence of submesoscale features. Surface divergence quickly decreases at increasing scales with a slope compatible with a turbulent process with broadband wavenumber spectrum, suggesting the influence of surface boundary layer processes such as wind effects, waves and Langmuir cells at the smaller scales. Vorticity, on the other hand, has a significantly slower decay, suggesting interaction between submesoscale and mesoscale dynamics. Results at 15 m are characterized by reduced ageostrophic dynamics with respect to the surface, especially for divergence. Submesoscale processes are present but appear attenuated in terms of KP magnitude and skewness. The results are generally consistent for the two experiments, despite the observed differences in the mixed layer stratification, suggesting that submesoscale instabilities occur mostly at surface fronts associated with filaments of Atlantic and Mediterranean waters that are present in both cases. The results are compared with previous literature results in other parts of the world ocean and a synthesis is provided. Good agreement with previous surface results is found, suggesting some general properties for divergence and vorticity scale dependence. The importance of further investigating very high resolution frontal processes at scales of tens of meters, as well as processes of interaction with high wind effects is highlighted.

The China United Assurance Society and the Making of Chinese Life Insurance, 1912–1949

This article traces the history of the first Chinese life insurance company: the China United Assurance Society. China United was founded in Shanghai in 1912 as a purely Chinese-owned enterprise and became the first Chinese life insurer to survive past its eighth year. By 1935, it boasted insurance in force of over 20 million yuan. In adapting life insurance to Republican China, China United had to contend with a number of extraordinary challenges. It had to train a corps of Chinese technical experts in a country without a single accredited actuary. It had to cultivate demand for a product that was poorly understood and often distrusted. At the same time, the Society was forced to find a way to manage a nationwide sales network that could market insurance products to a country that hitherto had little knowledge of life insurance. In doing so, it was threatened by interethnic strife sparked by racist practices of the foreign manager. Finally, China United had to overcome increasingly fierce competition, high lapse rates, and excess mortality that combined to drive underwriting profits negative. The Society was able to survive as a going concern only through its investing prowess in Chinese capital markets. Using previously unmined sources from the Shanghai Municipal Archives, this article charts China United’s turbulent process of indigenization, and explores its lasting legacies in the contemporary Chinese life insurance industry.

Entrainment in Resolved, Dry Thermals

Entrainment in cumulus convection remains ill understood and difficult to quantify. For instance, entrainment is widely believed to be a fundamentally turbulent process, even though Turner pointed out in 1957 that dry thermals entrain primarily because of buoyancy (via a dynamical constraint requiring an increase in radius r). Furthermore, entrainment has been postulated to obey a 1/r scaling, but this scaling has not been firmly established. Here, we study the classic case of dry thermals in a neutrally stratified environment using fully resolved direct numerical simulation. We combine this with a thermal tracking algorithm that defines a control volume for the thermal at each time, allowing us to directly measure entrainment. We vary the Reynolds number (Re) of our thermals between laminar (Re ≈ 600) and turbulent (Re ≈ 6000) regimes, finding only a 20% variation in entrainment rate ε, supporting the claim that turbulence is not necessary for entrainment. We also directly verify the postulated ε ~ 1/r scaling law.

The process of convergence of different social systems as a trend of modernity

The article attempts to examine the modernity through the prism of the transition of communities from the natural-historical to the socio-historical type of development. Convergence of various social systems is one of its most important trends. It is determined by a number of reasons, primarily the fact that the sustainable preservation of society in modern conditions is ensured by its development. Reforming of various countries mainly Russia and China is analyzed from the standpoint of convergence as a turbulent process. It is shown that the implementation of this trend contributes to the solution of current economic and social problems and its ignoring leads either to the immature forms of socialism or to the neoliberal model with all its negative consequences.

Pixel-level statistical analyses of prescribed fire spread

Wildland fire dynamics are a complex three-dimensional turbulent process. Cellular automata (CA) is an efficient tool to predict fire dynamics, but the main parameters of the method are challenging to estimate. To overcome this challenge, we compute statistical distributions of the key parameters of a CA model using infrared images from controlled burns. Moreover, we apply this analysis to different spatial scales and compare the experimental results with a simple statistical model. By performing this analysis and making this comparison, several capabilities and limitations of CA are revealed.

Safeguarding. A key dispositif of UNESCO’s Convention for the Safeguarding of Intangible Cultural Heritage

The expression ‘safeguarding intangible cultural heritage’ was formed within the context of transformations in the instruments and strategies for protecting cultural elements usually designated ‘folklore and traditional (and popular) culture’.1 The adoption of a ‘cultural heritage approach’ to this subject was a somewhat turbulent process that drew, since the mid-twentieth century, a winding path of dialogues with, and divergences from, common sense notions and mainstream preservationist culture. Throughout this process, political and conceptual possibilities for social engineering were envisaged, some were discarded, choices were legitimized and, no less importantly, networks were formed of agents and narrators of the political and legal negotiations that eventually lead to designing UNESCO ICH Convention as officially adopted. This path will be explored in the following comments on the formation of safeguarding as a cultural heritage policy dispositive2 and significant contrasts to other instruments, in relation to which it has acquired specificity, meaning and scope.

Turbulent characteristics of saltation and uncertainty of saltation model parameters

It is widely recognised that saltation is a turbulent process, similar to other transport processes in the atmospheric boundary layer. Due to a lack of high-frequency observations, the statistic behaviour of saltation is so far not well understood. In this study, we use the data from the Japan–Australia Dust Experiment (JADE) to investigate the turbulent characteristics of saltation by analysing the probability density function, energy spectrum and intermittency of saltation fluxes. Threshold friction velocity, u*t, and saltation coefficient, c0, are two important parameters in saltation models often assumed to be deterministic. As saltation is turbulent in nature, we argue that it is more reasonable to consider them as parameters obeying certain probability distributions. We estimate these distributions using the JADE data. The factors contributing to the stochasticity of u*t and c0 are examined.

Turbulent Characteristics of Saltation and Uncertainty of Saltation Model Parameters

It is widely recognized that saltation is a turbulent process, similar to other transport processes in the atmospheric boundary layer. But due to the lack of high frequency observations, the statistic behavior of saltation is so far not well understood. In this study, we use the data from the Japan-Australian Dust Experiment (JADE) to investigate turbulent saltation by analyzing the probability density function, energy spectrum and intermittency of saltation fluxes. Threshold friction velocity, u*t, and saltation coefficient, c0, are two important parameters in saltation models, often assumed to be deterministic. But as saltation is turbulent, we argue that it is more reasonable to consider them as parameters obeying certain probability distributions. The JADE saltation fluxes are used to estimate the u*t and c0 probability distributions. The stochasticity of these parameters is attributed to the randomness in friction velocity and threshold friction velocity as well as soil particle size.

The Role of Two-Dimensional Roughness Element in the Laminar-Turbulent Process in the Favorable Pressure Gradient of the Swept Wing

In the article using a liquid crystal thermography investigated the development of stationary and secondary disturbances, which were excited by cylindrical and two-dimensional roughness elements. It was shown, that two-dimensional roughness element has a destabilizing effect on disturbances, induced by cylindrical roughness element. Also the twodimensional roughness element is able to excite the stationary structures, and then the secondary disturbances the frequency interval of which is lower than in the case of stationary vortices excitation by cylindrical roughness element