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Clouds are notoriously difficult to simulate. Here, we separate and quantify the impact of Pacific climate modes on total cloud cover (TCC) variability, using reliable satellite observations together with state-of-the art reanalysis outputs, over the 1979–2020 period. The two most prominent modes of annual TCC variability show intense loadings over the Pacific basin and explain most of the variance in what could be considered the "signal" in satellite TCC data. Canonical correlation analysis (CCA) provides coupled TCC—sea surface temperature (SST) patterns that are linked to the Eastern Pacific (EP) ElNiño—Southern Oscillation (ENSO) and the Central Pacific (CP) ENSO in a physically consistent manner. The two ENSO modes dominate global coupled SST–TCC variability with the footprint of the CP ENSO explaining roughly half of the variance induced by the EP ENSO among these coupled fields. Both the EP and the CP ENSO exert an influence on Pacific decadal TCC variability. The impact of both ENSO modes on global total cloud cover variability is amplified by two positive feedbacks. These results could be used as a reference for model investigations on future projections of coupled TCC—SST variability responses to the CP and the EP ENSO. [ABSTRACT FROM AUTHOR]

The ability of TiO2 to generate reactive oxygen species under UV radiation makes it an efficient candidate in antimicrobial studies. In this context, the preparation of TiO2 microparticles coated with Ca- and Cu-based composite layers over which Cu(II), Cu(I), and Cu(0) species were identified is presented here. The obtained materials were characterized by a wide range of analytical methods, such as X-ray diffraction, electron microscopy (TEM, SEM), X-ray photoelectron (XPS), and UV-VIS spectroscopy. The antimicrobial efficiency was evaluated using qualitative and quantitative standard methods and standard clinical microbial strains. A significant aspect of this composite is that the antimicrobial properties were evidenced both in the presence and absence of the light, as result of competition between photo and electrical effects. However, the antibacterial effect was similar in darkness and light for all samples. Because no photocatalytic properties were found in the absence of copper, the results sustain the antibacterial effect of the electric field (generated by the electrostatic potential of the composite layer) both under the dark and in light conditions. In this way, the composite layers supported on the TiO2 microparticles' surface can offer continuous antibacterial protection and do not require the presence of a permanent light source for activation. However, the antimicrobial effect in the dark is more significant and is considered to be the result of the electric field effect generated on the composite layer. [ABSTRACT FROM AUTHOR]

Climate indices are often used as a climate monitoring tool, allowing us to understand how the frequency, intensity, and duration of extreme weather events are changing over time. Here, based on complex statistical analysis we identify highly correlated significant pairs of compound events at the highest spatial resolution, on a monthly temporal scale across Europe. Continental-scale monthly analysis unleashes information on compound events such as high-risk zones, hotspots, monthly shifts of hotspots and trends, risk exposure to land cover and population, and identification of maximum increasing trends. While there are many studies on single or compound climate extremes there are only a few studies that addresses the relationship between pairs of hazards, the incorporation of bioclimatic indices, the determination of a grid best-fit copula approach, and the outlining relevance of this work of compound event risks with exposures. In this respect, here, using 27-bivariate and 10-trivariate copula models, we show that the different hazard pairs have high combined risks of indices related to radiation, temperature, evapotranspiration, bioclimatic-based indices, such as the universal thermal climate index, wind chill index, and heat index, mainly over the northern and eastern European countries. Furthermore, we show that over the last 7 decades, agricultural and coastal areas are highly exposed to the risks of defined hotspots of compound events. In some of the hotspots of compound events-identified by clusters, there is no monthly shifts of hotspots, leading to higher impacts when compounded. Future work needs to integrate the framework and process to identify other compound pairs. [ABSTRACT FROM AUTHOR]

We present a new beech (Fagus sylvatica L.) tree-ring width composite chronology from five natural low-elevation forests in eastern Romania, which represent the species' continental distribution limit. Our regional beech chronology reflects April–June hydroclimate variability in form of the Standardized Precipitation Evapotranspiration Index over large parts of Romania, Ukraine, and the Republic of Moldova, for which high-resolution paleoclimatic evidence is broadly missing. Most of the reconstructed hydroclimatic extremes back to 1768 CE are confirmed by documentary evidences, and a robust association is found with large-scale atmospheric circulation patterns in the Northern Hemisphere and sea surface temperatures over the North Atlantic. Reconstructed pluvials coincide with a high-pressure system over the North Atlantic Ocean and north-western Europe, and with a low-pressure system over south-western, central and eastern Europe, whereas historical droughts coincide with a high-pressure system over Europe and a low-pressure system over the central part of the Atlantic Ocean. Our study demonstrates the potential to produce well-replicated, multi-centennial beech chronologies for eastern Europe to reconstruct regional hydroclimate variation and better understand the causes and consequences of large-scale teleconnection patterns. [ABSTRACT FROM AUTHOR]

The Atlantic Meridional Overturning Circulation (AMOC) is a tipping component of the climate system, with a quasi-global impact. Several numerical and observational studies emphasized two modes of AMOC variability, characterized by two distinct Atlantic sea surface temperature patterns. One is associated with centennial changes, the Trend Mode, and the other with the Atlantic Multidecadal Oscillation (AMO). The origin of the different manifestations of these modes it is not fully understood. Using observational data and an ocean general circulation model we present evidence that, whereas the Trend Mode is mainly linked with deep water formation in the Nordic Seas and with a North Atlantic AMOC cell centered at 50° N, AMO is related with deep water formation in the Labrador and Irminger Seas and with an overturning cell centered at 20° N. In combination with previous studies, these results imply that a main route of increasing atmospheric CO2 concentration influence on AMOC passes through deep water formation in the Nordic Seas and it is reflected in a subpolar North Atlantic meridional cell. [ABSTRACT FROM AUTHOR]

Global cloud cover represents a critical component of the climate system, with a considerable impact on the Earth's radiation budget. Small changes in clouds properties have a significant climatological impact because of the feedbacks that they generate, thus it is difficult to simulate the global cloud cover evolution in general circulation models. Observational investigations of cloud processes are constrained either by limited temporal and spatial extension of ground-based measurements or by imperfections in satellite data, like changes in geostationary satellite zenith angle, equatorial crossing time, or calibration. In this study, we used the Empirical Orthogonal Functions method to separate global patterns of total cloud cover variability in two satellite datasets from the International Satellite Cloud Climatology Project and the Pathfinder Atmospheres-Extended projects, each corrected for specific errors, and in the ERA5 Reanalysis. The first two modes explain most of the variance from what could be considered “signal” in both satellite data. Through Canonical Correlation Analysis, they are associated in a physically consistent manner with two different types of El Niño-Southern Oscillation (ENSO), namely the canonical ENSO which manifests itself in the eastern tropical Pacific and the El-Niño Modiki which manifest itself in the central Pacific. This work provides a comprehensive picture of the relationship between global total cloud cover and the tropical Pacific processes and indicates that cloud cover in the Indo-Pacific sector plays a significant role in the Earth radiative budget at interannual to decadal time scales. The similarity of the results across satellite and reanalysis data indicate that the both the observed and reanalysis cloud data sets contain consistent and valuable information related to global climate variability. [ABSTRACT FROM AUTHOR]

Due to its involvement in numerous feedbacks, sea ice plays a crucial role not only for polar climate but also at global scale. We analyse state-of-the-art observed, reconstructed, and modelled sea-ice concentration (SIC) together with sea surface temperature (SST) to disentangle the influence of different forcing factors on the variability of these coupled fields. Canonical Correlation Analysis provides distinct pairs of coupled Arctic SIC–Atlantic SST variability which are linked to prominent oceanic and atmospheric modes of variability over the period 1854–2017. The first pair captures the behaviour of the Atlantic meridional overturning circulation (AMOC) while the third and can be associated with the North Atlantic Oscillation (NAO) in a physically consistent manner. The dominant global SIC–Atlantic SST coupled mode highlights the contrast between the responses of Arctic and Antarctic sea ice to changes in AMOC over the 1959–2021 period. Model results indicate that coupled SST–SIC patterns can be associated with changes in ocean circulation. We conclude that a correct representation of AMOC-induced coupled SST–SIC variability in climate models is essential to understand the past, present and future sea-ice evolution. [ABSTRACT FROM AUTHOR]

The response of evapotranspiration to anthropogenic warming is of critical importance to the water and carbon cycle. Conflicting observations about changes of evapotranspiration stem mostly from the brevity of observations in time and space as well as a high degree of internal variability. Here we present the first gridded reconstruction of the European summer vapour pressure deficit (VPD) for the past four centuries. The gridded reconstruction is based on 26 European tree-ring oxygen isotope records and is performed using a Random Forest approach. Based on our reconstruction, we show that from the mid- 1700s a trend towards higher VPD occurred in Central Europe and the Mediterranean region which is based on the simultaneous increase in temperature and decrease in precipitation. This increasing VPD trend continues throughout the observational period and recent times. Climate model projections show this increase in VPD for the Mediterranean region continuing until the end of the 21st century, whereby the extent depends on the amount of greenhouse gas emissions. In contrast, projected VPD in North and Central Europe shows a tendency towards higher VPD only in the highest emission scenario. The reconstructed, observed and modelled VPD for past present and future is available here: https://doi.org/10.5281/zenodo.5958837 (Balting, D. F. et al., 2022). [ABSTRACT FROM AUTHOR]

Preventing and controlling the spread of multidrug-resistant (MDR) bacteria implicated in healthcare-associated infections is the greatest challenge of the health systems. In recent decades, research has shown the need for passive antibacterial protection of surfaces in order to reduce the microbial load and microbial biofilm development, frequently associated with transmission of infections. The aim of the present study is to analyze the efficiency of photocatalytic antimicrobial protection methods of surfaces using the new photocatalytic paint activated by light in the visible spectrum. The new composition is characterized by a wide range of analytical methods, such as UV-VIS spectroscopy, electron microscopy (SEM), X-ray powder diffraction (PXRD) or X-ray photoelectron spectroscopy (XPS). The photocatalytic activity in the UV-A was compared with the one in the visible light spectrum using an internal method developed on the basis of DIN 52980: 2008-10 standard and ISO 10678—2010 standard. Migration of metal ions in the composition was tested based on SR EN1186-3: 2003 standard. The new photocatalytic antimicrobial method uses a type of photocatalytic paint that is active in the visible spectral range and generates reactive oxygen species with inhibitory effect against all tested microbial strains. [ABSTRACT FROM AUTHOR]

Introduction: Inflammatory bowel diseases (IBD) are accompanied by an early and accelerated atherosclerotic process. Previous studies showed that Doppler ultrasonography and intima-media thickness (IMT) is a reliable marker for early atherosclerosis diagnosis. The aim of our study was to evaluate the presence of early atherosclerosis in a group of subjects with inflammatory bowel diseases, using Doppler ultrasonography and intima-media thickness (IMT) as a marker of subclinical atherosclerosis. Methods: A case-control study was conducted on 61 patients with inflammatory bowel disease and 19 healthy individuals. The included patients had an established IBD diagnosis, based on clinical, endoscopic, and histological criteria for at least 12 months. Results: In our study echo IMT was not significantly higher in IBD patients than in matched healthy controls. We found no difference between Crohn’s disease and ulcerative colitis patients or between conventional or biologic treatment regarding the echo IMT. Severity of the disease and its duration were predictors of an increased IMT. We found that disease activity (measured by the endoscopic scores and CRP) correlates with higher values of echo IMT. Also the presence of anemia reached statistical significance and was correlated with increased echo IMT in the biologic treatment group. Conclusions: In our study we found an increased echo IMT in IBD patients versus control, but the values did not reach statistical significance. We found no difference between Crohn’s disease and UC, conventional or biologic treatment. Age and duration of disease were corelated with increased IMT. Disease that was not controlled (high endoscopic, clinical and biological markers of activity) was correlated with increased echo IMT. The limitations of our study are that in our patients therapy was started early in the course of the disease and that the majority of the patients were in remission when echography was made. Further studies are necessary to evaluate factors correlated with early atherosclerosis in IBD and how echo IMT can be used as a tool in the proactive evaluation of these patients. [ABSTRACT FROM AUTHOR]

Winter climate variations in midlatitude regions have far-reaching effects on both natural and human systems worldwide. However, most climate reconstructions focus on either annual or summer climate conditions. Here we present a stalagmite stable isotope record from Urşilor Cave (Romania) where the δ 18O values are controlled by winter temperature. Because of its East-Central Europe (ECE) location, the cave site is well suited to capture variations in precipitation and temperature in response to changes in the North Atlantic region. Present day precipitation and temperature in this region are controlled by two teleconnection patterns, the Arctic Oscillation (AO) and the East Atlantic (EA). By analyzing composite maps for four different scenarios of AO and EA phase, we suggest that between 5.6 and 5.2 ka the positive phases of AO and EA became increasingly dominant. This shift led to generally warmer winters in northern Europe, but drier conditions in southern Europe and the Levant. Considering the compound effect of AO and EA on the hydroclimate of ECE, our study highlights the importance of examining the combined impact of teleconnection patterns on climate proxies influenced by various forcing mechanisms. • δ 18O values in calcite from stalagmite P from Urşilor Cave, Romania, are controlled by winter climate conditions. • Winter precipitation and air temperature are rature are controlled by the Arctic Oscillation (AO) and EAtlantic (EA)s and EA teleconnection patterns, respectively. • Comparing European speleothem δ 18O records reflecting winter climate, reveals important regional differences. • Between 5.6 and 5.2 ka, the dominance of AO+ oscillation and EA+ pattern gradually increased. [ABSTRACT FROM AUTHOR]

• We provide fundamentals of climate seasonality and break it down into external and internal forcing, and regional and local and modulating factors. • We present a transdisciplinary overview on how seasonality is recorded in, and extracted from, different palaeonvironmental archives. • We propose a framework for transparent communication of seasonality-related research across different communities. The role of seasonality is indisputable in climate and ecosystem dynamics. Seasonal temperature and precipitation variability are of vital importance for the availability of food, water, shelter, migration routes, and raw materials. Thus, understanding past climatic and environmental changes at seasonal scale is equally important for unearthing the history and for predicting the future of human societies under global warming scenarios. Alas, in palaeoenvironmental research, the term ' seasonality change ' is often used liberally without scrutiny or explanation as to which seasonal parameter has changed and how. Here we provide fundamentals of climate seasonality and break it down into external (insolation changes) and internal (atmospheric CO 2 concentration) forcing, and regional and local and modulating factors (continentality, altitude, large-scale atmospheric circulation patterns). Further, we present a brief overview of the archives with potentially annual/seasonal resolution (historical and instrumental records, marine invertebrate growth increments, stalagmites, tree rings, lake sediments, permafrost, cave ice, and ice cores) and discuss archive-specific challenges and opportunities, and how these limit or foster the use of specific archives in archaeological research. Next, we address the need for adequate data-quality checks, involving both archive-specific nature (e.g., limited sampling resolution or seasonal sampling bias) and analytical uncertainties. To this end, we present a broad spectrum of carefully selected statistical methods which can be applied to analyze annually- and seasonally-resolved time series. We close the manuscript by proposing a framework for transparent communication of seasonality-related research across different communities. [ABSTRACT FROM AUTHOR]