Emergence of global scaling behaviour in the coupled Earthatmosphere interaction

Scale invariance property in the global geometry of Earth may lead to a coupled interactive behaviour between various components of the climate system. One of the most interesting correlations exists between spatial statistics of the global topography and the temperature on Earth. Here we show that the power-law behaviour observed in the Earth topography via different approaches, resembles a scaling law in the global spatial distribution of independent atmospheric parameters. We report on observation of scaling behaviour of such variables characterized by distinct universal exponents. More specifically, we find that the spatial power-law behaviour in the fluctuations of the near surface temperature over the lands on Earth, shares the same universal exponent as of the global Earth topography, indicative of the global persistent role of the static geometry of Earth to control the steady state of a dynamical atmospheric field. Such a universal feature can pave the way to the theoretical understanding of the chaotic nature of the atmosphere coupled to the Earth’s global topography

The association between serum selenium and gestational diabetes mellitus: a systematic review and meta-analysis

Background: Results of the studies about association between serum selenium concentration and gestational hyperglycemia are inconsistent. Some studies have demonstrated that women with gestational diabetesmellitus (GDM) have lower Se concentrations while contrary results are reported in other studies. Aim: The aim of this study is to compare the serum Se concentration in women with GDM and normoglycemic pregnant women via a systematic review and meta-analysis. Methods: A computerized literature search on four databases (PubMed, Cochrane register of control trials, Scopus and Google scholar) was performed from inception through August 2013. Necessary data were extracted and random effects model was used to conduct the meta-analysis. Results: Six observational studies (containing 147 women with GDM and 360 normoglycemic pregnant women) were found, which had compared serum Se concentration in women suffering from GDM with normal pregnant ones. Our meta-analysis revealed that serum Se concentration was lower in women with GDM compared to normoglycemic pregnant women (Hedges = −1.34; 95% CI: −2.33 to −0.36; P < 0.01). Stratified meta-analysis demonstrated that concentration of Se in the sera of women with GDM was lower than normal pregnant women both in second and third trimesters, but the result was not significant in second trimester (second trimester: Hedges = −0.68; 95% CI: −1.60−0.25; P = 0.15, third trimester: Hedges = −2.81; 95% CI: −5.21 to −0.42; P < 0.05). It was also demonstrated that serum Se status was lower in pregnant women with impaired glucose tolerance (IGT) compared to normoglycemic pregnant women (Hedges = −0.85; 95% CI: −1.18 to −0.52). Conclusion: The available evidences suggest that serum Se concentration is significantly lower in pregnant women with gestational hyperglycemia compared to normal pregnant women

The long-standing dilemma of European summer temperatures at the mid-Holocene and other considerations on learning from the past for the future using a regional climate model

The past as an analogue for the future is one of the main motivations to use climate models for paleoclimate applications. Assessing possible model limitations in simulating past climate changes can lead to an improved understanding and representation of the response of the climate system to changes in the forcing, setting the basis for more reliable information for the future. In this study, the regional climate model (RCM) COSMO-CLM is used for the investigation of the mid-Holocene (MH, 6000 years ago) European climate, aiming to contribute to the solution of the long-standing debate on the reconstruction of MH summer temperatures for the region, and gaining more insights into the development of appropriate methods for the production of future climate projections. Two physically perturbed ensembles (PPEs) are first built by perturbing model physics and parameter values, consistently over two periods characterized by different forcing (i.e., the MH and pre-industrial, PI). The goal is to uncover possible processes associated with the considered changes that could deliver a response in MH summer temperatures closer to evidence from continental-scale pollen-based reconstructions. None of the investigated changes in model configuration produces remarkable differences with respect to the mean model behavior. This indicates a limited sensitivity of the model to changes in the climate forcing, in terms of its structural uncertainty. Additional sensitivity tests are further conducted for the MH, by perturbing the model initial soil moisture conditions at the beginning of spring. A strong spatial dependency of summer near-surface temperatures on the soil moisture available in spring is evinced from these experiments, with particularly remarkable differences evident over the Balkans and the areas north of the Black Sea. This emphasizes the role of soil–atmosphere interactions as one of the possible drivers of the differences in proxy-based summer temperatures evident between northern and southern Europe. A well-known deficiency of the considered land scheme of COSMO-CLM in properly retaining spring soil moisture, confirmed by the performed tests, suggests that more attention should be paid to the performance of the soil component of climate models applied to this case study. The consideration of more complex soil schemes may be required to help bridging the gap between models and proxy reconstructions. Finally, the distribution of the PPEs with changes in model configuration is analyzed for different variables. In almost all of the considered cases the results show that what is optimal for one period, in terms of a model configuration, is not the best for another characterized by different radiative forcing. These results raise concerns about the usefulness of automatic and objective calibration methods for RCMs, suggesting that a preferable approach is the production of small PPEs that target a set of model configurations, properly representing climate phenomena characteristic of the target region and that will be likely to contain the best model answer under different forcing

Regional moisture change over India during the past Millennium: A comparison of multi-proxy reconstructions and climate model simulations

AbstractThe Indian Monsoon Variability during the past Millennium has been simulated with the ECHAM5 model in two different time slices: Medieval Climate Anomaly and the Little Ice Age. The simulations are compared with new centennial-resolving paleo-reconstructions inferred from various well-dated multi-proxies from two core regions, the Himalaya and Central India. A qualitative moisture index is derived from the proxies and compared with simulated moisture anomalies.The reconstructed paleo-hydrological changes between the Little Ice Age and the Medieval Climate Anomaly depict a dipole pattern between Himalaya and Central India, which is also captured by the model.In the Medieval Climate Anomaly the model exhibits stronger (weaker) dipole signals during summer (winter) compared to Little Ice Age. In summer (winter) months of “Medieval Climate Anomaly minus Little Ice Age” the model simulates wetter conditions over eastern (western and central) Himalaya. Over Central India, a simulated weakening of Indian Summer Monsoon during warmer climate is coincident with reconstructed drying signal in the Lonar Lake record.Based on the model simulations, we can differentiate three physical mechanisms which can lead to the moisture anomalies: (i) the western and central Himalaya are influenced by extra-tropical Westerlies during winter, (ii) the eastern Himalaya is affected by summer variations of temperature gradient between Bay of Bengal and Indian subcontinent and by a zonal band of intensified Indian–East Asian monsoon link north of 25°N, and (iii) Central India is dominated by summer sea surface temperature anomalies in the northern Arabian Sea which have an effect on the large-scale advection of moist air masses. The temperatures in the Arabian Sea are linked to the Indo Pacific Warm Pool, which modulates the Indian monsoon strength

Assimilation of pseudo-tree-ring-width observations into an atmospheric general circulation model

Paleoclimate data assimilation (DA) is a promising technique to systematically combine the information from climate model simulations and proxy records. Here, we investigate the assimilation of tree-ring-width (TRW) chronologies into an atmospheric global climate model using ensemble Kalman filter (EnKF) techniques and a process-based tree-growth forward model as an observation operator. Our results, within a perfect-model experiment setting, indicate that the "online DA" approach did not outperform the "off-line" one, despite its considerable additional implementation complexity. On the other hand, it was observed that the nonlinear response of tree growth to surface temperature and soil moisture does deteriorate the operation of the time-averaged EnKF methodology. Moreover, for the first time we show that this skill loss appears significantly sensitive to the structure of the growth rate function, used to represent the principle of limiting factors (PLF) within the forward model. In general, our experiments showed that the error reduction achieved by assimilating pseudo-TRW chronologies is modulated by the magnitude of the yearly internal variability in the model. This result might help the dendrochronology community to optimize their sampling efforts

Enhancement of the Environmental Stability of Perovskite Thin Films via PMMA and AZ5214-Photoresist Coatings

We introduce a pioneering strategy to enhance the environmental stability of perovskite thin films, a critical step forward in advancing their application in optoelectronics. Through the innovative application of matrix encapsulation techniques, we focus on the stabilization of methylammonium lead iodide (MAPbI3) and methylammonium lead bromide (MAPbBr3) films. These films are meticulously prepared via a two-step solution deposition method under controlled ambient conditions. Our approach involves the application of poly(methyl methacrylate) (PMMA) and AZ5214 photoresist layers through spin-coating, aimed at singularly encapsulating the perovskite films. This encapsulation acts as a robust hydrophobic barrier, significantly mitigating moisture ingress and simultaneously addressing the challenge of pinhole presence within the perovskite structure. Through a series of detailed characterizations-spanning scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) spectroscopy-we demonstrate that, despite the thicker nature of the AZ5214 photoresist compared to the PMMA layer, it exhibits markedly enhanced stability. Notably, the integrity and optical properties of the perovskite films are preserved for extended periods of up to 960 hours under environmental exposure. This breakthrough highlights the superior performance of AZ5214 photoresist over PMMA in prolonging the operational life of perovskite thin films, thereby offering a promising avenue for their deployment in a wide range of optoelectronic devices

Effects of vitamin D-fortified low fat yogurt on glycemic status, anthropometric indexes, inflammation, and bone turnover in diabetic postmenopausal women: a rando...

Background & aims: Low levels of serum 25-hydroxy vitamin D (25(OH)D) are common in type 2 diabetic patients and cause several complications particularly, in postmenopausal women due to their senile and physiological conditions. This study aimed to assess the effects of vitamin D-fortified low fat yogurt on glycemic status, anthropometric indexes, inflammation, and bone turnover in diabetic postmenopausal women. Methods: In a randomized, placebo-controlled, double-blind parallel-group clinical trial, 59 postmenopausal women with type 2 diabetes received fortified yogurt (FY; 2000 IU vitamin D in 100 g/day) or plain yogurt (PY) for 12 weeks. Glycemic markers, anthropometric indexes, inflammatory, and bone turnover markers were assessed at baseline and after 12 weeks. Results: After intervention, in FY group (vs PY group), were observed: significant increase in serum 25(OH)D and decrease of PTH (stable values in PY); significant improvement in serum fasting insulin, HOMA-IR, HOMA-B, QUICKI, and no changes in serum fasting glucose and HbA1c (significant worsening of all indexes in PY); significant improvement in WC, WHR, FM, and no change in weight and BMI (stable values in PY); significant increase of omentin (stable in PY) and decrease of sNTX (significant increase in PY). Final values of glycemic markers (except HbA1c), omentin, and bone turnover markers significantly improved in FY group compared to PY group. Regarding final values of serum 25(OH)D in FY group, subjects were classified in insufficient and sufficient categories. Glycemic status improved more significantly in the insufficient rather than sufficient category; whereas the other parameters had more amelioration in the sufficient category. Conclusions: Daily consumption of 2000 IU vitamin D-fortified yogurt for 12 weeks improved glycemic markers (except HbA1c), anthropometric indexes, inflammation, and bone turnover markers in postmenopausal women with type 2 diabetes

Modellierung der asiatischen paläohydroklimatischen Variabilität

Using a multi-proxy and multi-model approach, this study aims to unravel the characteristics of modern- and palaeo-hydroclimatic variability over Asia. This is designed on different time-scales and diverse geographically distributed regions in Asia. Special emphasis is given to extreme hydro- meteorological events (e.g., mega-droughts). The main focus of this investigation is on climatically sensitive regions of Asia (e.g., monsoon- dominated and westerly-dominated regions). The combination of different model and proxy data leads to an enhanced understanding of the controlling mechanisms of the Asian climate dynamics. In this thesis, palaeoclimate simulations of different time-slices are carried out for selected time periods. The main focus lies in global and regional model simulations, as well as the sensitivity tests using these models. In a first step, existing global simulations for the past 1,000 years are analyzed, concentrating on dynamics of Asian monsoon and Westerlies, and on climate modes like El Niño Southern Oscillation (ENSO), Pacific North Atlantic Oscillation (PNA) and North Atlantic Oscillation (NAO) and their tele-connections with the Asian climate. In this regard, two Paleoclimate Modelling Intercomparison Project Phase III (PMIP3) / Coupled Model Intercomparison Project Phase 5 (CMIP5) climate model ensemble simulations of the past millennium have been analyzed to identify the occurrence of Asian mega-droughts. The Palmer Drought Severity Index (PDSI) is used as the key metric for the data comparison of hydro-climatological conditions. The model results are compared with the proxy data of the Monsoon Asia Drought Atlas (MADA). This study shows that Global Circulation Models (GCMs) are capable to capture the majority of historically recorded Asian monsoon failures at the right time and with a comparable spatial distribution. The simulations indicate that ENSO-like events lead in most cases to these droughts. Both, model simulations and proxy reconstructions, point to less monsoon failures during the Little Ice Age. During historic mega-droughts of the past millennium, the monsoon convection tends to assume a preferred regime described as "break" event in Asian monsoon. This particular regime is coincident with a notable weakening in Pacific Trade winds and Somali Jet. The interesting periods that are run and analyzed include extreme rainfall anomalies within the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). The generated model data are compared with the recently published paleo-data derived from different archives. The global simulations served as boundary conditions for regional climate and its transition from one climate period to another (e.g. from MCA to LIA). For the selected climatic periods typical circulation anomalies responsible for changes in regional climate and the physical mechanisms driving them are identified. Additional sensitivity simulations are carried out with and without Tibetan Plateau to investigate and compare the existing hypotheses on the behavior of Asian summer monsoon due to plateau forcing. The analysis of sensitivity experiments point out to the signicant impacts of Plateau forcing on the atmosphere-ocean tele- connections. It is shown that, in addition to the direct feedbacks of Tibetan Plateau orography on the climate of Asia, such as sensible heat pumping and thermal insulation, other signicant processes exist, which link the Asian summer monsoon to the sea surface temperatures in the North Atlantic Ocean. A removal of the Tibetan Plateau modifiees the wind-driven ocean circulations over the North Atlantic, leading to a decrease of surface heat advection over the North Atlantic Ocean and a decrease of the Atlantic Meridional Overturning Circulation. This, in turn, affects via teleconnections both the monsoon rainfall and the position of the intertropical convergence zone. A climate modelling approach is presented to reproduce the rainfall patterns over Iran due to the climatic forcings during the past 6,000 years. The selected periods are simulated using a spatially high-resolved atmosphere General Circulation Model (GCM). The results show that the winter rainfall patterns over Iran have changed due to the changes in solar insolation to a wetter condition starting around 3,000 yr BP and reaching its maximum during the Medieval Climate Anomaly ca. 1,000 yr BP. The rainfall variability can be explained by the changes in the climate energy balance as a result of changing incoming solar irradiance based on the Milankovitch theory. A shift in the earth energy balance leads to the modulation of the West Asian Subtropical Westerly Jet (WASWJ). The investigations support the hypothesis that during the Holocene a northward shift in the WASWJ contributes to the less cyclonic activities over Iran. This brings less moisture into the region during the winter.Das Ziel dieser Arbeit ist die Charakteristika der rezenten und historischen hydroklimatischen Variabilität in Asien zu untersuchen. Dazu wird ein Multi- Proxy und Multi-Modell-Ansatz verwendet unter Betrachtung verschiedener Zeitskalen, als auch verschiedener Regionen in Asien. Der besondere Fokus liegt auf extremen hydrometeorologischen Ereignissen (z.B. Mega-Droughts) und der Schwerpunkt der Untersuchung liegt dabei auf klimatisch sensiblen Regionen Asiens (z.B. Monsun-dominierte und Westwind-dominierte Regionen). Für ein besseres Verständnis der Klimadynamik im asiatischen Raum ist die Kombination verschiedener Modelle sowie Proxy-Daten notwendig. In dieser Arbeit werden Paläoklimasimulationen verschiedener Zeitscheiben für ausgewählte Zeiträume durchgeführt. Der Schwerpunkt liegt auf globalen und regionalen Modellsimulationen, sowie auf Sensitivitätstests unter Verwendung dieser Modelle. Im ersten Schritt werden bestehende globale Simulationen für die letzten 1.000 Jahre analysiert. Der Fokus liegt dabei auf der Dynamik des asiatischen Monsuns und der Westerlies sowie auf Telekonnektionsmustern wie El Niño Southern Oscillation (ENSO), Pacific Nordatlantische Oszillation (PNA), Nordatlantischeszillation (NAO) und deren Verbindungen mit dem asiatischen Klima. In diesem Zusammenhang wurden zwei Klimamodell Ensemble-Simulationen des vergangenen Jahrtausends (Paleoclimate Modelling Intercomparison Project Phase III (PMIP3)/ Coupled Model Intercomparison Project Phase 5 (CMIP5)) analysiert, um das Auftreten extremer asiatischen Dürren (Mega-Droughts) zu identifizieren. Der Palmer Drought Severity Index (PDSI) wird verwendet, um die hydro-klimatischen Bedingungen in den verschiedenen Modellläufen zu vergleichen. Die Modellergebnisse werden mit den Proxy-Daten des Monsoon Asian Drought Atlas (MADA) verglichen. Diese Studie zeigt, dass globale Zirkulationsmodelle (GCMs) in der Lage sind, die Mehrheit der historisch aufgezeichneten asiatischen Monsun-Breaks zur richtigen Zeit und mit einer vergleichbaren räumlichen Verteilung zu erfassen. Die Simulationen zeigen, dass ENSO-ähnliche Ereignisse in den meisten Fällen auf diese Dürren folgen. Sowohl Modellsimulationen als auch Proxy-Rekonstruktionen zeigen weniger Monsun-Breaks während der Kleinen Eiszeit. Während der historischen Mega- Droughts des letzten Jahrtausends wird ein Regime bevorzugt, in dem die Konvektion des Monsuns stark reduziert ist. Dieses Regime wird als Break-Phase bezeichnet. Diese besondere Regelung fällt mit einer bemerkenswerten Abschwächung der Pazifischen Passatwinde und des Somali-Jets zusammen. Es werden vier Perioden simuliert und ausgewertet, jeweils zwei innerhalb der Medieval Climate Anomaly (MCA) und der Kleinen Eiszeit. Die erzeugten Modelldaten werden mit Paläo-Daten aus verschiedenen Proxies verglichen. Die globalen Simulationen dienen als Randbedingungen für regionale Klimasimulationen und zur Untersuchung des Übergangs zwischen zwei Klimaperioden (z.B. von MCA zu LIA). Für die ausgewählten Klimaperioden wurden anhand typischer Zirkulationsanomalien physikalische Mechanismen identifiziert, die den regionalen Klimawandel erklären. In zusätzlichen Sensitivitätsstudien, in denen das Hochland von Tibet in der Simualtion entfernt wurde, werden die bestehenden Hypothesen bezüglich des Einflusses des Plateaus auf den asiatischen Sommermonsun untersucht. Die Analysen der Sensitivitätsexperimente zeigen wesentliche Auswirkungen des Plateaus auf Telekonnektionen zwischen Atmosphäre und Ozean. Es wird gezeigt, dass neben den direkten Auswirkungen der tibetischen Orographie auf das asiatische Klima, wie Sensible Heat Pumping und Thermal Insulation, weitere wichtige Prozesse auftreten, die den asiatischen Sommermonsun mit den Meeresoberflächentemperaturen im Nordatlantikozean verbinden. Die Reduktion der Höhe des tibetischen Plateaus in der Simulation modifiziert die windgetriebenen Meereszirkulationen über dem Nordatlantik, was zu einer Abnahme der Wärmeadvektion an der Meeresoberfläche im Nordatlantik und eine Abschwächung der Ozeanzirkulation im Atlantik führt. Dies wiederum wirkt sich über Telekonnektionen sowohl auf die Monsunregenfälle als auch auf die Position der innertropischen Konvergenzzone aus. Des weiteren wird ein Ansatz vorgestellt, um anhand der klimatischen Antriebe der letzten 6.000 Jahre die Niederschlagsverteilungen im Iran zu reproduzieren. Die ausgewählten Perioden werden unter Verwendung eines räumlich hochaufgelösten atmosphärischen globalen Zirkulationsmodell (GCM) simuliert. Die Ergebnisse zeigen, dass sich die Winterniederschlagsmuster über dem Iran ab etwa 3.,000 Jahren aufgrund der Veränderungen der Sonneneinstrahlung hin zu einem feuchteren Zustand geändert und während MCA vor ca. 1.000 Jahren das Maximum erreicht haben. Die Niederschlagsvariabilität kann durch die Veränderungen der Energiebilanz als Folge der Änderung der eingehenden solaren Strahlung auf Grundlage der Milankovitch-Theorie erklärt werden. Eine Verschiebung in der Energiebilanz der Erde führt zur Modulation des Westasian Subtropical Westerly Jets (WASWJ). Die Untersuchungen stützen die Hypothese, dass während des Holozäns eine Nordwärtsverschiebung des WASWJ zu einer Reduktion der Zyklonenaktivität über dem Iran führt. Das führt wiederum im Winter zu einer Reduktion der Feuchtigkeit in der Region

Exploring the impact of the recent global warming on extreme weather events in Central Asia using the counterfactual climate data ATTRICI v1.1

International audienceAbstract We study the impact of recent global warming on extreme climatic events in Central Asia (CA) for 1901-2019 by comparing the composite representation of the observational climate with a hypothetical counterfactual one that does not include the long-term global warming trend. The counterfactual climate data are produced based on a simple detrending approach, using the global mean temperature (GMT) as the independent variable and removing the long-term trends from the climate variables of the observational data. This trend elimination is independent of causality, and the day-to-day variability in the counterfactual climate remains preserved. The analysis done in the paper shows that the increase in frequency and magnitude of extreme temperature and precipitation events can be attributed to global warming. Specifically, the probability of experiencing a +7 K temperature anomaly event in CA increases by up to a factor of seven in some areas due to global warming. The analysis reveals a significant increase in heatwave occurrences in Central Asia, with the observational climate dataset GSWP3-W5E5 (later called also factual) showing more frequent and prolonged extreme heat events than hypothetical scenarios without global warming. This trend, evident in the disparity between factual and counterfactual data, underscores the critical impact of recent climatic changes on weather patterns, highlighting the urgent need for robust adaptation and mitigation strategies. Additionally, using the self-calibrated Palmer drought severity index (scPDSI), the sensitivity of dry and wet events to the coupled precipitation and temperature changes is analyzed. The areas under dry and wet conditions are enhanced under the observational climate compared to a counterfactual scenario, especially over the largest deserts in CA. The expansion of the dry regions aligns well with the pattern of desert development observed in CA in recent decades

The Youth Life Style in Tehran and its Determining Factors

The goal of this research is on the one hand to identify various life styles of the youth living in Tehran and, on the other hand, to study several social, economic and cultural factors affecting the youth life styles. Based on Cookran formula, sample size amounts to 400, and cluster sampling was used as sampling method. Studying existing theories and reviewing empirical studies relevant to the research subject matter, various life styles such as aesthetical-hedonistic, functionalistic, sub-cultural, and passive ones were identified. According to the mean rates of various life styles, the hedonistic one enjoyed the highest rate, amounting to 53% of the sample population, the functionalistic one showed a moderate rate of 46.8 of the sample population, and the lowest rate belonged to the passive life style. Based on the person correlation coefficient, it could be said that there was a positive and meaningful relationship between social capital and various types of life styles. Also, a meaningful relationship of 0.01 existed between cultural capital and various types of life style. Moreover, person correlation coefficient confirms the meaningful and positive relationship between economic capital and functionalistic, hedonistic and passive life styles. Using step by step method in the multi-variable regression shows the economic variables contribution in explaining the life styles variable as to be as 0.31, the social ones as to 0.17, and cultural capital impact as to 0.16. In sum, taking into consideration R2 coefficient, the three mentioned variables explain 19% of the variance of the life style variable