Mean Trend Research Articles

Regional pollen-based Holocene temperature and precipitation patterns depart from the Northern Hemisphere mean trends

Abstract. A mismatch between model- and proxy-based Holocene climate change, known as the “Holocene conundrum”, may partially originate from the poor spatial coverage of climate reconstructions in, for example, Asia, limiting the number of grid cells for model–data comparisons. Here we investigate hemispheric, latitudinal, and regional mean time series and time-slice anomaly maps of pollen-based reconstructions of mean annual temperature, mean July temperature, and annual precipitation from 1908 records in the Northern Hemisphere extratropics. Temperature trends show strong latitudinal patterns and differ between (sub-)continents. While the circum-Atlantic regions in Europe and eastern North America show a pronounced Middle Holocene temperature maximum, western North America shows only weak changes, and Asia mostly shows a continuous Holocene temperature increase. Likewise, precipitation trends show certain regional peculiarities such as the pronounced Middle Holocene precipitation maximum between 40 and 50∘ N in Asia and Holocene increasing trends in Europe and western North America, which can all be linked with Holocene changes in the regional circulation pattern responding to temperature change. Given a background of strong regional heterogeneity, we conclude that the calculation of global or hemispheric means, which initiated the Holocene conundrum debate, should focus more on understanding the spatiotemporal patterns and their regional drivers.

Regional wave climate projections forced by EURO‐CORDEX winds for the Black Sea and Sea of Azov towards the end of the 21st century

AbstractWave phenomena impact high commercial value coastal and offshore activities, infrastructures and transportation. The knowledge of future wave conditions allows for consistent long‐term planning and decision‐making. The present study aims to provide robust, reliable projections of the potential future wave conditions of the Black Sea under the influence of climate change. For this purpose, an eight‐member dynamic wave climate ensemble that accurately represents the Black Sea's present wave climate has been produced, and future projections are assessed and analysed here. The wave climate ensemble was obtained by forcing the Simulating Waves Nearshore spectral wave model with eight regional wind fields from the EURO‐CORDEX. The future simulations of the regional wind fields are based on the RCP8.5 high‐emission scenario. The historical wave climate of the ensemble was evaluated against ERA5 reanalysis data. Projected changes in the mean wind and wave characteristics are examined by comparing historical and future simulations. In addition, the projected trends in the annual means during the future period of the wave simulations for significant wave height (Hs) and wave energy flux are also analysed. The projections for Hs and wind speeds are pronounced with significant decreases down to −10% across the basin, especially in the eastern region of the Black Sea. Changes in the Hs 99% percentiles of up to 16% are projected to occur. The projected changes in the annual mean of the wave energy flux are close to the projected changes in Hs means, while the seasonal changes (between −15% and 12%) are expected to be higher.

Decomposition of meteorological and anthropogenic contributions to near-surface ozone trends in Northeast China (2013–2021)

Recent years have seen an increase in regional ozone (O3) pollution in China. This study explored the interannual variability in daily maximum 8-h average O3 concentration (MDA8-O3) in Northeast China (NEC) and its three subregions (Liaoning, Jilin, and Heilongjiang) during 2013–2021, and identified the key meteorological drivers underlying the observed variability. The Kolmogorov–Zurbenko filtering technique was applied to a stepwise multiple linear regression model to decompose the meteorological and anthropogenic contributions to annual MDA8-O3 trends. The results showed that the spatiotemporal variation of MDA8-O3 in NEC is characterized by a high–south and low–north pattern with an MDA8-O3 hotspot in the Bohai Rim area. Over the 9-year study period, a significant increasing trend (∼2.5% a−1, P < 0.05) in the regional mean of the annual 90th percentile of MDA8-O3 was detected across NEC. This trend was strongly relevant to changes in relative humidity and surface solar radiation downward (SSRD). Statistical analyses revealed that SSRD dominated MDA8-O3 variability spatially over almost the entire NEC region. Additionally, the contribution decomposition suggested that the trend of increase in annual average MDA8-O3 in NEC was dominated by anthropogenic emission change, which explained 91.9% of the total variation. Regionally, although the dominant role of emissions has not changed, the meteorology-driven anomalies also explained −4.3%–3.3% of the annual average MDA8-O3 variation. This study provides insight into decoupling the complex relationships between long-term variability in regional O3 pollution and both anthropogenic emissions and meteorology, which could provide valuable information for future efforts to address the O3 pollution in NEC.

Changes in Stratosphere‐Troposphere Exchange of Air Mass and Ozone Concentration in CCMI Models From 1960 to 2099

AbstractThis study investigates changes in stratosphere‐troposphere exchange (STE) of air masses and ozone concentrations from 1960 to 2099 using multiple model simulations from Chemistry Climate Model Initiative (CCMI) under climate change scenario RCP6.0. We employ a lowermost stratosphere mass budget approach with dynamic isentropic surfaces fitted to the tropical tropopause as the upper boundary of lowermost stratosphere. The multi‐model mean (MMM) trends of air mass STEs are all small over all regions, which are within 0.3 (0.1) % decade−1 for 1960–2000 (2000–2099). The MMM trends of ozone STE for 1960–2000 are 0.3%, −2.7%, 3.4%, −0.9%, and −2.7% decade−1 over the Northern hemisphere (NH) extratropics, Southern hemisphere (SH) extratropics, tropics, extratropics, and globe, respectively. The corresponding ozone STE trends for 2000–2099 are 3.0%, 4.3%, 0.8%, 3.5%, and 4.7% decade−1. Changes in ozone STEs are dominated by ozone concentration changes, driven by climate‐induced changes and ozone‐depleting substance (ODS) changes. For 1960–2000, small changes in ozone STEs in the NH extratropics are due to a cancellation between effects of climate‐induced changes and ODS increases, while the ODS effect dominates in the SH extratropics, leading to a large ozone STE magnitude decrease. Increased ozone transport from tropical troposphere to stratosphere for 1960–2000 is due to increased tropospheric ozone. A decreased global ozone STE magnitude for 1960–2000 was largely caused by ODS‐induced ozone loss that is partly compensated by climate‐induced ozone changes. For 2000–2099, about two‐thirds of global ozone STE magnitude increases are caused by ozone increases in the extratropical lower stratosphere due to climate‐induced changes. The remaining one‐third is caused by ozone recovery due to the phaseout of ODS.

Temporal trends in the physical fitness of Hong Kong children aged 6–12 years between 2003–04 and 2015–16

ABSTRACT Low physical fitness in childhood is linked with poor health now and in later life. This study estimated temporal trends in physical fitness for Hong Kong children aged 6–12 years from 2003–04 to 2015–16. Objectively measured body size and physical fitness data for 27,513 children were obtained from four population-representative surveys of Hong Kong primary school students. Temporal trends in means were estimated by population-weighted linear regression. Trends in distributional characteristics were visually described. Overall, there was a small increase in mean height (effect size (ES) = 0.20 (95%CI: 0.13, 0.28)), with a negligible increase (ES < 0.2) in mean body mass. When adjusted for trends in age, gender, and body size, there was a small decline in sit-and-reach performance (ES = –0.43 (95%CI: −0.43, −0.42)), a small improvement in 9-min run/walk performance (9-to-12-year-olds, ES = 0.26 (95%CI: 0.26, 0.27)), with negligible declines in handgrip strength, 6-min run/walk (6-to 8-year-olds), and sit-ups performance. Temporal trends were not always uniform across the population distribution, with declines in run/walk, sit-ups, and sit-and-reach performance generally largest in children with low fitness. Increased national health promotion strategies that address culturally specific factors are encouraged to further improve the existing trends, especially for children with low fitness.

Trends in climate change observed under tropical wet and tropical montane climates; A case study from Sri Lanka

Climate change-related changes in temperature and precipitation trends must be investigated at local, regional and global levels. Temperature and precipitation trends in two selected regions having tropical wet and tropical montane climates (i.e., Colombo and Nuwara Eliya respectively) in Sri Lanka were studied for a 30 year period from 1989 to 2019, to evaluate the temporal dynamics of climate change. Precipitation trends were analyzed on annual, monthly, and seasonal scales, while the trends in mean, minimum, and maximum temperatures were examined on annual and monthly scales. Decadal time series plots were used to study decadal variations in average temperature and precipitation. The trends in extreme temperature and precipitation events were also evaluated. In addition, the trends in diurnal temperature range (DTR), cool and warm nights, and heat index (HI) were studied. The significance of trends was evaluated using the Mann-Kendall test, while the magnitude of the slope was assessed by Sen’s slope estimator. Clear statistically significant increasing trends were observed for the mean annual temperatures under the tropical wet and tropical montane climates, and no clear trends were observed in annual precipitation in both districts. There were decreasing trends in south-west monsoon rainfall, with a significant decrease in Nuwara Eliya under the tropical montane climate. Increasing trends were observed for the average monthly precipitation in November (i.e., during the inter-monsoonal rains) and average monthly temperature in April (i.e., the hottest month) over the last decade (i.e., 2010-2019) in Colombo. The DTR has significantly decreased over the last three decades in Colombo. A significant upward trend was observed for HI values during the last decade in Colombo. Colombo also showed a statistically significant decreasing trend in the number of cool nights and a statistically significant decreasing trend in the number of warm nights over the last decade.

Four Decades of Trends and Drivers of Global Surface Ocean Acidification

AbstractThe oceans are acidifying in response to the oceanic uptake of anthropogenic carbon dioxide (CO2) from the atmosphere, yet the global‐scale progression of this acidification has been poorly documented so far by observations. Here, we fill this gap and use an updated version of the in situ and satellite observation‐based product OceanSODA‐ETHZ to determine the trends and drivers of the surface ocean aragonite saturation state (Ωar) and pH = –log([H+]) (total scale) over the last four decades (1982–2021). In the global mean, Ωar and pH declined at rates of −0.071 ± 0.006 decade−1 and −0.0166 ± 0.0010 decade−1, respectively, with the errors of the trends largely reflecting the uncertainties in the reconstructed pH and Ωar fields. These global mean trends are driven primarily by the increase in surface ocean concentration of dissolved inorganic carbon (DIC) in response to the uptake of anthropogenic CO2, but moderated by changes in natural DIC. Surface warming enhances the decrease in pH, accounting for ∼15% of the global trend. The long‐term trends vary substantially across regions and also differ distinctly between pH and Ωar. The highest trends in pH are found in the high latitudes, while Ωar decreases the fastest in the low latitudes. These regional differences are primarily a consequence of regional differences in the ability of the surface ocean to take up and buffer the anthropogenic CO2. Substantial El Niño‐driven interannual variability is superimposed on these trends, with Ωar showing greater variability than pH, resulting in substantially longer time of emergence for Ωar.

The suitability of differentiable, physics-informed machine learning hydrologic models for ungauged regions and climate change impact assessment

Abstract. As a genre of physics-informed machine learning, differentiable process-based hydrologic models (abbreviated as δ or delta models) with regionalized deep-network-based parameterization pipelines were recently shown to provide daily streamflow prediction performance closely approaching that of state-of-the-art long short-term memory (LSTM) deep networks. Meanwhile, δ models provide a full suite of diagnostic physical variables and guaranteed mass conservation. Here, we ran experiments to test (1) their ability to extrapolate to regions far from streamflow gauges and (2) their ability to make credible predictions of long-term (decadal-scale) change trends. We evaluated the models based on daily hydrograph metrics (Nash–Sutcliffe model efficiency coefficient, etc.) and predicted decadal streamflow trends. For prediction in ungauged basins (PUB; randomly sampled ungauged basins representing spatial interpolation), δ models either approached or surpassed the performance of LSTM in daily hydrograph metrics, depending on the meteorological forcing data used. They presented a comparable trend performance to LSTM for annual mean flow and high flow but worse trends for low flow. For prediction in ungauged regions (PUR; regional holdout test representing spatial extrapolation in a highly data-sparse scenario), δ models surpassed LSTM in daily hydrograph metrics, and their advantages in mean and high flow trends became prominent. In addition, an untrained variable, evapotranspiration, retained good seasonality even for extrapolated cases. The δ models' deep-network-based parameterization pipeline produced parameter fields that maintain remarkably stable spatial patterns even in highly data-scarce scenarios, which explains their robustness. Combined with their interpretability and ability to assimilate multi-source observations, the δ models are strong candidates for regional and global-scale hydrologic simulations and climate change impact assessment.

Changes in mean and extreme homogeneous precipitation in China during 1960–2020

This study aims to explore the observed national and regional changes in the seasonal mean and extreme precipitation in mainland China between 1960 and 2020 using data from 678 stations. Tests of homogeneity (e.g. standard normal homogeneity test, Pettitt's test and Buishand range test) are applied to identify homogeneous stations for the trend analysis. The non-parametric Mann-Kendall test and a modified Theil-Sen slope estimator were then used to examine changes in the precipitation characteristics. Our results show that despite a decreasing trend in the frequency of wet days, the mean precipitation has actually increased. Extreme precipitation has also increased, and in many locations, at greater rates than those of the mean. This is principally due to a greater rate of increase per degree of warming, of 8% for extreme precipitation compared to 7% for the mean. However, considerably regional and seasonal variability has been seen in the trends. Mean and extreme precipitation trends are positive throughout in western China for all seasons, but they vary in eastern China. Mean precipitation increased slightly in the southeast but decreased in the northeast of the country. Extreme precipitation increased in both regions, but the increases were greater in the southeast. Trends, additionally, also differed within regions, especially over eastern China. In southeast China, precipitation increased in the east and decreased in the west. In northeast China, precipitation increased in the north and decreased in the south. Using a multiple regression model, we found that changes during summer precipitation clearly dominate the overall annual changes in most regions. Most long-term changes over eastern China appear to be linked to those of the East-Asian and South-Asian Summer Monsoons.

Cardiac Dimensions in Normal Pregnancy: A Prospective Study.

Pregnancy, a unique physiologic state, is associated with several changes in the various body systems. The cardiovascular system is one of the systems affected, with chronic volume overload being one of the characteristic changes experienced during pregnancy. Cardiovascular disease in pregnancy is the leading cause of non-obstetric maternal death worldwide. This study aims to determine and describe the changes in left and right ventricular and atrial sizes in systole and diastole in the course of normal pregnancy. A cohort study was conducted among healthy pregnant women between the age of 18 and 40 who attended the antenatal clinic of Federal Medical Centre (FMC), Yenagoa, Bayelsa State. Fifty women were recruited during the first trimester (T1) of pregnancy and followed up until six weeks postpartum. Ethical approval was obtained from the Research Ethics Committee of Federal Medical Centre, Yenagoa, with approval number FMCY/REC/ECC/2019/JAN/150. Clinical evaluation, hematologic, biochemical, and anthropometric assessments, and two-dimensionalM-mode and Doppler echocardiography were done for the participants in each trimester of pregnancy and at six weeks postpartum. The clinical and echocardiographic parameters were analyzed using Statistical Package for the Social Sciences (SPSS) version 22.0 (IBM Corp., Armonk, NY, USA). The mean trend ofleft ventricular posterior wall thickness in diastole (LVPWd) and left ventricular posterior wall thickness in systole (LVPWs) increased progressively from the first to third trimester (T3) (not statistically significant) but dropped towardinitial values in postpartum to the level that was statistically significant for LVWPd alone when compared to baseline first trimester values. The left atrial diameter in systole (LADs) was largest in the third trimester, and the left atrial volume index (LAVI)and right ventricular basal diameter (RVD1) also showed a similar trend. The left ventricular internal diameter (LVID) in both systole and diastole increased progressively from the first to the third trimesters, but the increase was only statistically significant between the third trimester (T3) and the first trimester (T1). The right atrial diameter (RAD) and right atrial volume (RAV) alsoincreased progressively from the first to the third trimesters, but the increase was only statistically significant between the third trimester (T3) and the first trimester (T1). Changes were noticed in the cardiac chamber sizes during pregnancy. However, this reversed back to levels similar to the first trimester during the postpartum period. To aid in the early detection and treatment of cardiovascular disorders in pregnancy,screening of apparently healthy pregnant women who later developed complaints is advised as cardiovascular changes could be significant during pregnancy.

Future climate change projections in the agroecological, bioclimatic, biogeographical and altitudinal vegetation zones of Morocco

AbstractMorocco is located in a region vulnerable to the impacts of climate change, which can have profound effects on its social, economic and environmental systems. This makes studies aimed at forecasting these impacts in future using climate models particularly important. However, the generally coarse spatial resolution of models, combined with a large number of models, imposes a limitation on the models, allowing the selection of the most appropriate ones for climate change impact assessments in a specific region. In this study, 38 GCMs and GCM‐RCMs from CMIP5 ensemble and CORDEX project were downscaled and bias‐corrected for use in projecting climate change over Morocco under the RCP4.5 and RCP8.5 scenarios. A three‐step sequential process was adopted, involving in that order the selection of models based on: (i) projection of climate means; (ii) projection of climate extremes; and (iii) ability of the models to simulate the baseline climate. Climate projections show precipitation decreases of up to 10% by the beginning of the century, with decreases of more than 20% under RCP8.5 projected by 2100, with the central and northern mountainous regions of the country being the most affected. Seasonal projections showed autumn months likely to experience the greatest decline in precipitation, up to 36.56% by the end of the century. Temperature projections revealed an upward trend in mean, maximum and minimum temperatures, with increases of up to 3°C predicted by mid‐century over most of the country, particularly in the winter months. Our results point to a concerning future, with impacts related to decreased precipitation and increased temperatures expected to be many and varied across the country. Nevertheless, they can help provide a knowledge base for efforts to mitigate and adapt to expected changes.

Quantifying grade benefits of study: Practice makes better

Problem Roulette (PR), an online study service at the University of Michigan, offers points-free formative practice to students preparing for examinations in introductory science, technology, engineering, and mathematics courses. Using four years of PR data involving millions of problem attempts by thousands of students, we quantify the benefits of increased practice study volume in introductory physics. After conditioning the mean final grade on standardized (ACT and SAT) math test score, we analyze deviations based on student study volume. We find a strong effect; mean course grade rises quadratically with the logarithm of the total number of PR questions encountered over the term (NQ,tot), with an overall gain of 0.77±0.12 grade points between 1<NQ,tot<1000. The gains are persistent across the range of math test scores represented in our sample. While NQ,tot surely correlates with other study habits, the benefits of increased study in general still hold. A model for final grade using test score and study volume largely accounts for demographic stratification, including by sex, parental education level, number of parents at home, nationality or underrepresented minority status, and regional income level, with two significant exceptions: students whose parents did not earn a college degree, who earn −0.27±0.04 grade points (6.1σ) below expectations, and underrepresented minority students at −0.14±0.04 points (3.6σ). Residual scatter in final grade remains comparable to the maximal study gains, implying that the model is far from deterministic: individual variation trumps mean trends. Our findings can help motivate students to study more and help teachers to identify which types of students may especially need such encouragement.1 MoreReceived 20 December 2022Accepted 25 April 2023DOI:https://doi.org/10.1103/PhysRevPhysEducRes.19.010139Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasInstructional materials developmentLearning environmentLearning theoryScientific reasoning & problem solvingStudent preparationTechnologyPhysics Education Research

Localized Strong Warming and Humidification Over Winter Japan Tied to Sea Ice Retreat

AbstractEast Asian winter weather has altered dramatically in response to progressing climate change. However, analysis of time‐averaged atmospheric fields might obscure climate change signals that could relate to specific types of events. This study aimed to detect climate change signals for various background atmospheric fields by applying classification to daily surface pressure patterns. We found a pronounced trend of increase in surface air temperature over Japan since the 1980s, stronger than the seasonal mean trend, when dominating cold air advection from the Sea of Okhotsk. This cold air was warmed and humidified by the retreat of sea ice in the Sea of Okhotsk. In contrast, the warming trend was mitigated when warm air advection was dominant. These results highlight the importance of daily background atmospheric conditions in amplifying and localizing the impact of regional climate change.

A method for partitioning trends in genetic mean and variance to understand breeding practices

BackgroundIn breeding programmes, the observed genetic change is a sum of the contributions of different selection paths represented by groups of individuals. Quantifying these sources of genetic change is essential for identifying the key breeding actions and optimizing breeding programmes. However, it is difficult to disentangle the contribution of individual paths due to the inherent complexity of breeding programmes. Here we extend the previously developed method for partitioning genetic mean by paths of selection to work both with the mean and variance of breeding values.MethodsFirst, we extended the partitioning method to quantify the contribution of different paths to genetic variance assuming that the breeding values are known. Second, we combined the partitioning method with the Markov Chain Monte Carlo approach to draw samples from the posterior distribution of breeding values and use these samples for computing the point and interval estimates of partitions for the genetic mean and variance. We implemented the method in the R package AlphaPart. We demonstrated the method with a simulated cattle breeding programme.ResultsWe show how to quantify the contribution of different groups of individuals to genetic mean and variance and that the contributions of different selection paths to genetic variance are not necessarily independent. Finally, we observed that the partitioning method under the pedigree-based model has some limitations, which suggests the need for a genomic extension.ConclusionsWe presented a partitioning method to quantify sources of change in genetic mean and variance in breeding programmes. The method can help breeders and researchers understand the dynamics in genetic mean and variance in a breeding programme. The developed method for partitioning genetic mean and variance is a powerful method for understanding how different selection paths interact within a breeding programme and how they can be optimised.

Effects of Wind-Induced Error on the Climatology and Trends of Observed Precipitation in China from 1960 to 2018

Abstract Since the 1950s, precipitation has been measured at national weather stations in China using national standard precipitation gauges. Gauges without a wind fence can significantly underestimate precipitation amounts, while this undercatch bias is closely related to surface wind speed and precipitation type. The observed surface wind speed across China has substantially declined during the past decades. Therefore, this study investigated the wind-induced error of the observed precipitation and its impact on regional and national mean trends in precipitation over China due to the reduction in surface wind speed. It was found that the wind-induced error for the mean annual precipitation nationwide was 29.28 mm yr−1, accounting for 3.92% of total precipitation amount. The variation of precipitation at the regional scale was large but the trends were both positive and negative, approximately cancelling at the national level and resulting in a small national mean trend. The raw observation data showed that the national mean precipitation increased at a rate of 1.85 mm yr−1 (10 a)−1 from 1960 to 2018, which was reduced to 0.33 mm yr−1 (10 a)−1 after correction, demonstrating that the correction of wind-induced error had an important impact on the trend of annual precipitation. Meanwhile, the reduction of surface wind speed was consistent at both the regional and national levels. On average, the wind-induced errors decreased at rates of −1.52, −1.34, and −0.14 mm yr−1 (10 a)−1 for total precipitation, rainfall, and snowfall, respectively. It illustrates that the decreases of the wind-induced error result in the increasing precipitation of raw observation.

Historical global ocean wave data simulated with CMIP6 anthropogenic and natural forcings

This dataset presents historical ocean wave climate during 1960–2020, simulated using the numerical model WAVEWATCH III (WW3) forced by Coupled Model Intercomparison Project phase 6 (CMIP6) simulations corresponding to natural-only (NAT), greenhouse gas-only (GHG), aerosol-only (AER) forcings, combined forcing (natural and anthropogenic; ALL), and pre-industrial control conditions. Surface wind at 3-hourly temporal resolution, and sea-ice area fraction at monthly frequency, from a CMIP6 model - MRI-ESM2.0 are used to force WW3 over the global ocean. Model calibration and validation of the significant wave height are carried out using inter-calibrated multi-mission altimeter data produced by the European Space Agency Climate Change Initiative, with additional corroboration using ERA-5 reanalysis. The simulated dataset is assessed for its skill to represent mean state, extremes, trends, seasonal cycle, time consistency, and spatial distribution over time. Numerically simulated wave parameters for different individual external forcing scenario is not available yet. This study produces a novel database particularly useful for detection and attribution analysis to quantify the relative contributions of natural and anthropogenic forcings to historical changes.

Rainfall Trends Analysis in context of Climate Change in Imam Turki Bin Abdullah Royal Nature Reserve (ITBA) – Saudi Arabia

Rainfall trend analysis, on different spatial and temporal scales, has been used during the past century as the indicate of global climate change by the scientific community. According to some recent studies, the Nature Reserve (ITBA) has been suffering a rainfall decrease, especially in the second half of the studied period (1993-2018). The aim of the present study is to analyze the rainfall trends using the time series of 52 years in five rain stations (Linah, Rafha, Ha’il, Dawmat Al Jandal and Hafr Al Batin) surrounding the Nature Reserve of (ITBA) that extended on area of about 91500 km2 in the Northeast of Saudi Arabia. The trends analysis of annual rainfall, rainy days, shows that the fluctuations or variations in climatic parameters is a recurring phenomena in the studied stations. Inter-annual variability of the rainfall and the actual mean of daily rainfall are characterized by the high coefficients of variation, varying from 0.73 (Linah) to 0.83 (Ha’il) and from 0.53 (Linah) to 1.09 (Rafha), respectively. The variance test of Fmax-ratio method indicates the homogeneous annual rainfall distribution at Linah, Rafha and Ha’il, the homogenous rainy days distribution at only Ha’il and the homogeneous distribution of the actual mean of the daily rainfall at only Linah. The trends of annual rainfall, rainy days and actual mean of the daily rainfall obtained by using T-student test are significant in Ha’il and Dawmat Al Jandal, in all stations and in only Hafr Al Batin, respectively.

Trends in unhealthy lifestyle factors in US NHANES respondents with cardiovascular disease for the period between 1999 and 2018.

To examine national trends in unhealthy lifestyle factors among adults with cardiovascular disease (CVD) in the United States (US) between 1999 and 2018. We analyzed data from National Health and Nutrition Examination Survey (NHANES), a nationally representative survey of participants with CVD who were aged ≥20 years, which was conducted between 1999 and 2000 and 2017-2018. CVD was defined as a self-report of congestive heart failure, coronary heart disease, angina, heart attack, or stroke. The prevalence rate of each unhealthy lifestyle factor was calculated among adults with CVD for each of the 2-year cycle surveys. Regression analyses were used to assess the impact of sociodemographic characteristics (age, sex, race/ethnicity, family income, education level, marital status, and employment status). The final sample included 5610 NHANES respondents with CVD. The prevalence rate of their current smoking status remained stable among respondents with CVD between 1999 and 2000 and 2017-2018. During the same period, there was a decreasing trend in the age-adjusted prevalence rate of poor diet [primary American Heart Association (AHA) score <20; 47.5% (37.9%-57.0%) to 37.5% (25.7%-49.3%), p < 0.01]. Physical inactivity marginally increased before decreasing, with no statistical significance. The prevalence rate of sedentary behavior increased from 2007 to 2014 but subsequently returned to its original level in 2018 with no statistical significance. The age-adjusted prevalence rate of obesity increased from 32% (27.2%-36.8%) in 1999-2000 to 47.9% (39.9%-55.8%) in 2017-2018 (p < 0.001). The age-adjusted prevalence rate of depression increased from 7% (4.2%-9.9%) in 1999-2000 to 13.9% (10.2%-17.6%) in 2017-2018 (p = 0.056). Trends in mean for each unhealthy lifestyle factor were similar after adjustment for age. We found that respondents who had low education and income levels were at a higher risk of being exposed to unhealthy lifestyle factors (i.e., smoking, poor diet, and physical inactivity) than those who had high education and income levels. There is a significant reduction in the prevalence rate of poor diet among US adults with CVD between 1999 and 2018, while the prevalence rate of obesity showed increasing trends over this period. The prevalence rate of current smoking status, sedentary behavior, and depression was either stable or showed an insignificant increase. These findings suggest that there is an urgent need for health policy interventions targeting unhealthy lifestyles among adults with CVD.

North‐West Europe Hottest Days Are Warming Twice as Fast as Mean Summer Days

AbstractEurope has seen a rapid increase in the frequency and intensity of hot extremes in recent decades. In this study it is shown, using ERA5 reanalysis data 1960–2021, that the hottest summer days in North‐West Europe are warming approximately twice as fast as mean summer days. Moreover, this pattern stands out as relatively unusual across the Northern Hemisphere. It is also shown that comprehensive climate models fail to capture this difference in trends. A hypothesis is suggested to explain the differential rate of warming between the mean and hottest days, namely that the hottest days are often linked to warm advection from Iberia and North Africa, areas that are warming faster than North‐West Europe. This hypothesis can account for about 25% of the difference between ERA5 and a climate model ensemble and hence further research is needed to understand the drivers of the differing trends in mean and extreme temperature.

Trends of Aboveground Net Primary Productivity of Patagonian Meadows, the Omitted Ecosystem in Desertification Studies

The United Nations defines desertification as the loss of productivity in arid and semiarid environments. The extended steppes of Patagonia harbor small meadows whose compounded area is comparatively small, but their aboveground net primary production (ANPP) is up to ten times higher than their surroundings. These meadows then represent a key ecosystem for cattle grazing systems, but there are no descriptions of the trends in their ANPP and, consequently, their carrying capacity, and, as a result, their degradation syndromes. Our objectives were as follows: (1) analyze the trends of mean and spatial heterogeneity of annual ANPP in meadows and neighboring steppes and relate them with precipitation and temperature, (2) evaluate the impact on the livestock carrying capacity of meadows in the region, and (3) evaluate the degradation trends of these meadows, based on a novel description proposed to characterize the trend syndromes of these type of ecosystems. We identified meadow areas across a subcontinental scale in Patagonia, covering a mean annual precipitation range from 129 to 936 mm. We estimated ANPP on a monthly basis from 2000 to 2019 via regional calibrated remote sensing information. In the last two decades, ANPP decreased in 74% of the studied meadow areas, while remaining relatively stable in the nearby steppes. This decrease was relatively higher in the arid end of the analyzed precipitation gradient. Hence, the global carrying capacity for all the studied meadow areas decreased by 8%. Finally, we identified four trend syndromes based on the combination of the ANPP trend and its spatial heterogeneity, calculated as the spatial standard deviation. The predominant trend syndrome, in 55% of the area, was associated with a negative trend of both ANPP and spatial heterogeneity. These results could help prioritize areas where specific management decisions, given the different trend syndromes, could help revert ANPP negative trends.