Evaluation and application of Finite Element Sea Ice-Ocean Model (FESOM) for the Arctic-North Atlantic region in variable resolution global simulations

The changes and variability of the Arctic-North Atlantic Oceans and the inter-exchange of water mass and heat is of crucial relevance for the global ocean and climate. In this work the Finite Element Sea-ice Ocean Model (FESOM) is used to simulate the global ocean with focus on the Arctic-North Atlantic region. FESOM is formulated on unstructured meshes and offers variable-resolution functionality which is diffcult to achieve in traditional structured-mesh models. With this powerful tool we are able to resolve the key areas with locally refined resolutions in global simulations. The performance of FESOM in the Arctic Ocean and North Atlantic on large time scales is first evaluated in a 240-yr hindcast experiment. The model can reproduce realistic Atlantic Meridional Overturning Circulation (AMOC) and realistic Arctic freshwater content variability and sea ice extent. A water-hosing experiment is conducted to study the model sensitivity to increased freshwater input from Greenland Ice Sheet (GrIS) melting in a 0.1Sv discharge rate scenario. The released freshwater from Greenland can penetrate into the Arctic Ocean, especially in the Eurasian Basin. The anomalous freshwater also leads to a reduction in the AMOC strength and changes in freshwater exchange between the two oceans. Simulations with different local resolutions of 24 km and 9 km in the Arctic Ocean and surrounding regions are carried out to study the influence of resolution on the simulated Arctic Ocean and Arctic-Subarctic fluxes. Both simulations can reasonably simulate the mean state and variability of sea ice condition, freshwater content in the Arctic Ocean, and the fluxes through the Arctic gateways when compared to observations and previous model studies. Although the high resolution (9 km) run tends to improve the representation of fluxes through the Arctic gateways and the salinity structure in the Arctic basin, higher meso-scale eddy resolving resolution is required to further improve the simulation. The driving mechanism of the interannual variability of Barents Sea sea ice is studied. We found that sea ice import into the Barents Sea drives the sea ice interannual variability. The amount of sea ice flux determines the thermodynamic growth rate in the Barents Sea. The increasing trend of Atlantic Water heat flux through the Barents Sea Opening leads to the decline of Barents Sea ice volume

Developmental differences in the structure of executive function in middle childhood and adolescence

Although it has been argued that the structure of executive function (EF) may change developmentally, there is little empirical research to examine this view in middle childhood and adolescence. The main objective of this study was to examine developmental changes in the component structure of EF in a large sample (N = 457) of 7–15 year olds. Participants completed batteries of tasks that measured three components of EF: updating working memory (UWM), inhibition, and shifting. Confirmatory factor analysis (CFA) was used to test five alternative models in 7–9 year olds, 10–12 year olds, and 13–15 year olds. The results of CFA showed that a single-factor EF model best explained EF performance in 7–9-year-old and 10–12-year-old groups, namely unitary EF, though this single factor explained different amounts of variance at these two ages. In contrast, a three-factor model that included UWM, inhibition, and shifting best accounted for the data from 13–15 year olds, namely diverse EF. In sum, during middle childhood, putative measures of UWM, inhibition, and shifting may rely on similar underlying cognitive processes. Importantly, our findings suggest that developmental dissociations in these three EF components do not emerge until children transition into adolescence. These findings provided empirical evidence for the development of EF structure which progressed from unity to diversity during middle childhood and adolescence

Mechanisms Driving the Interannual Variability of the Bering Strait Throughflow

The Bering Strait throughflow has important implications for the Arctic freshwater, heat, and nutrients. By keeping the interannual variabilities of the atmospheric forcing only inside or outside the Arctic Ocean in numerical simulations, we can quantify their relative contributions to the interannual variability of the throughflow. We found that winds play a much more important role for the throughflow interannual variability than buoyancy forcing. Winds over the western Arctic Ocean and North Pacific determine the direction of Ekman transport, thus changing the sea surface height gradient between the two basins, and consequently influencing the volume transport strength. Although winds over the two basins are similarly important for the variance of ocean volume transport, the North Pacific winds cause stronger variability in freshwater and heat transports through modifying the inflow temperature and salinity. After 1994, winds over the western Arctic Ocean explain a larger part of the variability of Bering Strait volume transport than the winds outside the Arctic Ocean

A 4.5 km resolution Arctic Ocean simulation with the global multi-resolution model FESOM1.4

In the framework of developing a global modeling system which can facilitate modeling studies on Arctic Ocean and high- to midlatitude linkage, we evaluate the Arctic Ocean simulated by the multi-resolution Finite Element Sea ice-Ocean Model (FESOM). To explore the value of using high horizontal resolution for Arctic Ocean modeling, we use two global meshes differing in the horizontal resolution only in the Arctic Ocean (24 km vs. 4.5 km). The high resolution significantly improves the model's representation of the Arctic Ocean. The most pronounced improvement is in the Arctic intermediate layer, in terms of both Atlantic Water (AW) mean state and variability. The deepening and thickening bias of the AW layer, a common issue found in coarse-resolution simulations, is significantly alleviated by using higher resolution. The topographic steering of the AW is stronger and the seasonal and interannual temperature variability along the ocean bottom topography is enhanced in the high-resolution simulation. The high resolution also improves the ocean surface circulation, mainly through a better representation of the narrow straits in the Canadian Arctic Archipelago (CAA). The representation of CAA throughflow not only influences the release of water masses through the other gateways but also the circulation pathways inside the Arctic Ocean. However, the mean state and variability of Arctic freshwater content and the variability of freshwater transport through the Arctic gateways appear not to be very sensitive to the increase in resolution employed here. By highlighting the issues that are independent of model resolution, we address that other efforts including the improvement of parameterizations are still required

HSF-1 attenuates isoflurane-induced cognitive dysfunction by inhibiting TLR2 expression

Purpose: To investigate the regulatory effects of heat shock factor 1 (HSF-1) in the progression of postoperative cognitive dysfunction (POCD). Methods: Isoflurane (ISO)-induced POCD model in rats was established to determine the role of HSF-1 in POCD. Morris water maze test was used to evaluate the learning and memory abilities of the POCD rats while mRNA and protein levels of HSF-1 were determined by RNA extraction/quantitative real-time polymerase chain reaction (RT-qPCR) and western blot analysis, respectively. Results: The mRNA and protein levels of HSF-1 were significantly reduced in ISO model, but OE-HSF-1 treatment significantly elevated HSF-1 level (p < 0.05). ISO treatment also significantly decreased escape latency but increased the decreased target quadrant of the rats, while HSF-1 upregulation reversed these effects (p < 0.05). Additionally, HSF-1 alleviated ISO-induced hippocampal injury, improved ISO-induced hippocampal inflammation, and inhibited ISO-induced hippocampal apoptosis. Furthermore, HSF-1 was modulated by POCD via TLR2/NF-κB pathway (p < 0.05). Conclusion: HSF-1 attenuates ISO-induced cognitive dysfunction by suppressing TLR2 expression. This activity provides a potential strategy to prevent POCD via HSF-1

Impacts of strong wind events on sea ice and water mass properties in Antarctic coastal polynyas

Strong offshore wind events (SOWEs) occur frequently near the Antarctic coast during austral winter. These wind events are typically associated with passage of synoptic- or meso-scale cyclones, which interact with the katabatic wind field and affect sea ice and oceanic processes in coastal polynyas. Based on numerical simulations from the coupled Finite Element Sea-ice Ocean Model (FESOM) driven by the CORE-II forcing, two coastal polynyas along the East Antarctica coast––the Prydz Bay Polynya and the Shackleton Polynya are selected to examine the response of sea ice and oceanic properties to SOWEs. In these polynyas, the southern or western flanks of cyclones play a crucial role in increasing the offshore winds depending on the local topography. Case studies for both polynyas show that during SOWEs, when the wind speed is 2–3 times higher than normal values, the offshore component of sea ice velocity can increase by 3–4 times. Sea ice concentration can decrease by 20–40%, and sea ice production can increase up to two to four folds. SOWEs increase surface salinity variability and mixed layer depth, and such effects may persist for 5–10 days. Formation of high salinity shelf water (HSSW) is detected in the coastal regions from surface to 800 m after 10–15 days of the SOWEs, while the HSSW features in deep layers exhibit weak response on the synoptic time scale. HSSW formation averaged over winter is notably greater in years with longer duration of SOWEs

Speed Effect Analysis Using the CFA Framework

The paper outlines a method for investigating the speed effect due to a time limit in testing. It is assumed that the time limit enables latent processing speed to influence responses by causing omissions in the case of insufficient speed. Because of processing speed as additional latent source, the customary confirmatory factor model is enlarged by a second latent variable representing latent processing speed. For distinguishing this effect from other method effects, the factor loadings are fixed according to the cumulative normal distribution. With the second latent variable added, confirmatory factor analysis of reasoning data (N=518) including omissions because of a time limit yielded good model fit and discriminated the speed effect from other possible effects due to the item difficulty, the homogeneity of an item subset and the item positions. Because of the crucial role of the cumulative normal distribution for fixing the factor loadings a check of the normality assumption is also reported

Speed Effect Analysis Using the CFA Framework

The paper outlines a method for investigating the speed effect due to a time limit in testing. It is assumed that the time limit enables latent processing speed to influence responses by causing omissions in the case of insufficient speed. Because of processing speed as additional latent source, the customary confirmatory factor model is enlarged by a second latent variable representing latent processing speed. For distinguishing this effect from other method effects, the factor loadings are fixed according to the cumulative normal distribution. With the second latent variable added, confirmatory factor analysis of reasoning data (N=518) including omissions because of a time limit yielded good model fit and discriminated the speed effect from other possible effects due to the item difficulty, the homogeneity of an item subset and the item positions. Because of the crucial role of the cumulative normal distribution for fixing the factor loadings a check of the normality assumption is also reported

Water color from Sentinel-2 MSI data for monitoring large rivers: Yangtze and Danube

Rivers provide key ecosystem services that are inherently engineered and optimized to meet the strategic and economic needs of countries around the world. However, limited water quality records of a full river continuum hindered the understanding of how river systems response to the multiple stressors acting on them. This study highlights the use of Sentinel-2 Multi-Spectral Imager (MSI) data to monitor changes in water color in two optically complex river systems: the Yangtze and Danube using the Forel-Ule Index (FUI). FUI divides water color into 21 classes from dark blue to yellowish brown stemming from the historical Forel-Ule water color scale and has been promoted as a useful indicator showing water turbidity variations in water bodies. The results revealed contrasting water color patterns in the two rivers on both spatial and seasonal scales. Spatially, the FUI of the Yangtze River gradually increased from the upper reaches to the lower reaches, while the FUI of the Danube River declined in the lower reaches, which is possibly due to the sediment sink effect of the Iron Gate Dams. The regional FUI peaks and valleys observed in the two river systems have also been shown to be related to the dams and hydropower stations along them. Seasonally, the variations of FUI in both systems can be attributed to climate seasonality, especially precipitation in the basin and the water level. Moreover, land cover within the river basin was possibly a significant determinant of water color, as higher levels of vegetation in the Danube basin were associated with lower FUI values, whereas higher FUI values and lower levels of vegetation were observed in the Yangtze system. This study furthers our knowledge of using Sentinel-2 MSI to monitor and understand the spatial-temporal variations of river systems and highlights the capabilities of the FUI in an optically complex environment