Mann-Kendall Trend Test Research Articles

Analysis of Changes in Water Flow after Passing through the Planned Dam Reservoir Using a Mixture Distribution in the Face of Climate Change: A Case Study of the Nysa Kłodzka River, Poland

Climate change and extreme weather events have the potential to increase the occurrences of flooding and hydrological droughts. Dam reservoir operation can mitigate or aggravate this impact. This study aims to evaluate the influence of the planned Kamieniec Ząbkowicki dam reservoir on the flow patterns of the Nysa Kłodzka river in the context of changing hydrological conditions and climate change. In the study, a 40-year observational series of hydrological data was used to simulate changes in water flow through the river valley in a numerical model. This simulation was conducted both for the natural river valley and for the same river valley but with the added reservoir dam. Flow simulations revealed that dam operation increased downstream flow values, reducing variability in extreme high-flow events. Addition, the mixture log-normal distribution shows that the operation of the dam resulted in a reduction in the variability of both low flows and extreme high-flow events. Furthermore, the model illustrates that moderate-flow conditions remain relatively stable and similar before and after dam construction. The Mann–Kendall trend test, Sen slope trend test and Innovative Trend Analysis indicated that the dam had a significant impact on flow trends, reducing the negative trend. This hydrotechnical structure stabilizes and regulates flows, especially in response to climate-induced changes. These findings highlight the effectiveness of the dam in mitigating flood risk and supporting water resource management. It is essential to consider the role of the dam in adapting to changing hydrological conditions influenced by climate change. For practical application, efficient flow regulation by reservoir administration is crucial.

Historical carbon peak situation and its driving mechanisms in the commercial building sector in China

Evaluating the peak situation of commercial building carbon emissions (CBCE) at the provincial level and revealing their differentiated driving mechanisms are extremely significant for achieving the national “Dual carbon” target. In this study, a new provincial-level carbon peak situation assessment model is constructed to evaluate the historical CBCE peak situations in China by integrating conditional judgement function, Mann-Kendall trend test, and Tapio decoupling model. Furthermore, the STIRPAT model and grouped regression model are combined to investigate the driving mechanisms on CBCE under different carbon peaking situations. Results showed that the CBCE in Beijing have reached the peak, and Shandong and Inner Mongolia have entered the peak potential period. Beijing achieved the decoupling of CBCE from value added of tertiary sector and floor space per capita. The most important factors leading to different peak situations of CBCE are commercial floor space per capita and energy intensity. Urban population, industrial structure, value added of tertiary industry per capita and energy structure show different degrees of influence on different peak stages of CBCE. This study provides a general methodology for evaluating the carbon peak situation and its driving mechanism. It sets the foundation for the formulation of the differentiated carbon peak pathway and provides a reference for the carbon emission assessment of other countries with regional carbon peak differences in the world.

Internet Search Trends for Common Hand Surgery Diagnoses.

The internet is a common resource for patients seeking health information. Trends in internet search interests for common hand surgery diagnoses and their seasonal variations have not been previously studied. The objectives of this study were (1) to describe the temporal trends in internet search interest for common hand surgery diagnoses in the recent five-year time period and (2) to assess seasonal variations in search term interest. An internet-based study of internet search term interest of 10 common hand surgery diagnoses was performed using Google Trends (Google, Inc., Mountain View, CA) from January 2017 to December 2021. The 10 diagnoses were "carpal tunnel syndrome," "trigger finger," "thumb arthritis," "ganglion cyst," "de Quervain's tenosynovitis," "lateral epicondylitis," "Dupuytren disease," "distal radius fracture," "finger fracture," and "scaphoid fracture." Analysis of variance (ANOVA) was used to assess for seasonal differences in search interest, and temporal trends were assessed using the two-tailed Mann-Kendall trend test. During the study period, there was an increasing trend for search interest for "carpal tunnel syndrome," "trigger finger," "thumb arthritis," "Dupuytren disease," and "finger fracture," both in the United States and worldwide. There was no significant temporal trend for "ganglion cyst," "de Quervain's tenosynovitis," "lateral epicondylitis," and "distal radius fracture." There were no significant temporal trend for "scaphoid fracture" in the United Statesand a decreasing trend worldwide. There was significant seasonal variation in search term interest for "finger fracture" in the United States, "finger fracture" worldwide, and "scaphoid fracture" in the United States, with popularity peaking in the fall. Despite growth in global internet usage, internet search interest has remained stagnant for many common hand surgery conditions, which may represent a shifting preference for patients to obtain health information from other resources. Internet search interest for traumatic hand conditions corresponds to seasonal variations in fracture epidemiology and peaks in the fall season.

How Himalayan communities are changing cultivation practices in the context of climate change

Climate change can have significant impacts on crop yields and food security. This study assessed the linkages between climate change and crop yields to obtain a better understanding on the drivers of food security. The study was conducted in Pasagaun village of Lamjung District in Nepal, where household surveys and focus group discussions (FGDs) were used to collect data including crop cultivation, irrigation facilities, and adaptation strategies. Moreover, climate data (temperature and precipitation) from 1992 to 2020 were collected from the Khudi Bazar meteorological station and crop yield data were obtained from the Agri-Business Promotion and Statistics Division. Trend analysis of temperature and precipitation was conducted using Mann-Kendall trend test and Sen's Slope method, and the results showed an increase in the average temperature of approximately 0.02 ​°C/a and a decrease in the annual precipitation of 9.84 mm/a. The cultivation of traditional varieties of rice and foxtail millet (Kaguno) has vanished. Although, there was no significant impact of the maximum temperature on the yield of rice and maize, the regression analysis revealed that there are negative relationships between rice yield and annual minimum temperature (r ​= ​−0.44), between millet yield and annual precipitation (r ​= ​−0.30), and between maize yield and annual minimum temperature (r ​= ​−0.31) as well as positive relationship between rice yield and annual precipitation (r ​= ​0.16). Moreover, average rice yield and millet yield have decreased by 27.0% and 57.0% in 2000–2020, respectively. Despite other reasons for the decrease in crop yield such as the lack of irrigation facilities, out-migration of farmer, and increased pest infestation, respondents have adopted adaptation strategies (for example, shifts in cultivation time and changes in crop types) to minimize the impacts of climate change. More investigation and community-based farming education are needed to understand and alleviate the harmful impacts of climate change on crop yield, as effective adaptation coping strategies are still insufficient. This study provides insights into the adaptation strategies that are necessary to keep food security in the face of climate change.

Temporal trends in neurosurgical volume and length of stay in a public healthcare system: A decade in review with a focus on the COVID-19 pandemic.

Over the past decade, neurosurgical interventions have experienced changes in operative frequency and postoperative length of stay (LOS), with the recent COVID-19 pandemic significantly impacting these metrics. Evaluating these trends in a tertiary National Health Service center provides insights into the impact of surgical practices and health policy on LOS and is essential for optimizing healthcare management decisions. This was a single tertiary center retrospective case series analysis of neurosurgical procedures from 2012 to 2022. Factors including procedure type, admission urgency, and LOS were extracted from a prospectively maintained database. Six subspecialties were analyzed: Spine, Neuro-oncology, Skull base (SB), Functional, Cerebrospinal fluid (CSF), and Peripheral nerve (PN). Mann-Kendall temporal trend test and exploratory data analysis were performed. 19,237 elective and day case operations were analyzed. Of the 6 sub-specialties, spine, neuro-oncology, SB, and CSF procedures all showed a significant trend toward decreasing frequency. A shift toward day case over elective procedures was evident, especially in spine (P < 0.001), SB (tau = 0.733, P = 0.0042), functional (tau = 0.156, P = 0.0016), and PN surgeries (P < 0.005). Over the last decade, decreasing LOS was observed for neuro-oncology (tau = -0.648, P = 0.0077), SB (tau = -0.382, P = 0.012), and functional operations, a trend which remained consistent during the COVID-19 pandemic (P = 0.01). Spine remained constant across the decade while PN demonstrated a trend toward increasing LOS. Most subspecialties demonstrate a decreasing LOS coupled with a shift toward day case procedures, potentially attributable to improvements in surgical techniques, less invasive approaches, and increased pressure on beds. Setting up extra dedicated day case theaters could help deal with the backlog of procedures, particularly with regard to the impact of COVID-19.

Unravelling the elevation-dependent warming in the Indus Basin

The Elevation Dependent Warming (EDW) in the mountain regions have wider implications to its cryosphere, hydrological, and ecological systems. This paper explores an EDW in the Indus River Basin, considering Jhelum, Kabul, and Indus sub-basins to improve the accuracy and understanding of cryospheric and hydrological changes in the basin. We use the maximum (Tmax), minimum (Tmin), and mean (Tmean) near surface atmospheric temperature data from 21 ground stations for the 1988–2021 period and applied the Mann-Kendall (MK) trend tests for exploring the trends in the data. The results show that Tmax and Tmin has significant (p < 0.001) warming trends in the Upper Indus Basin (UIB) until 2210 mean above sea level (m asl). Tmax has increased with a rate of 0.031 °C yr−1 (p < 0.001) while Tmin increased with a rate of 0.029 °C yr−1 (p < 0.001), hence the “diurnal temperature range (DTR) also increased significantly” (0.015 °C yr−1, p < 0.001). In this study, a symmetric pattern of increasing trends has been observed in Tmax and Tmin. Moreover, Tmax has increasing trends throughout the period in the middle and high-altitude regions, except in Autumn and Monsoon seasons, respectively. While more significant and prominent increasing trend observed in Tmax during the winter season. Thus, this consistent warming trends in all seasons with more prominent trend in the winter season for Tmax can have harmful impact on the cryosphere of the region and ultimately, leading to water scarcity and extreme droughts.

Drought Assessment in Greece Using SPI and ERA5 Climate Reanalysis Data

The present work aims to assess the spatial variability and the trends of the annual rainfall and meteorological drought in the entire territory of Greece utilising the ERA5 reanalysis precipitation dataset of the European Centre for Medium-Range Weather Forecasts (ECMWF), which spans from January 1940 to December 2022 (an 83-year period). Drought assessment took place based on the Standardized Precipitation Index (SPI) for timescales ranging from 1 month to 12 months. Evaluation was carried out by calculating SPI using observed rainfall data from five meteorological stations. The annual rainfall and drought severity trends for timescales of 1 (SPI-1), 3 (SPI-3), 6 (SPI-6) and 12 (SPI-12) months were analysed using the Theil–Sen slope method and the Mann–Kendall trend test. The results indicate significant, both increasing and decreasing, annual precipitation trends at the 95% significance level for the Aegean Islands, western Crete and western mainland of Greece. The results also indicate significant drought trends for SPI-12 for the Aegean Islands and western Peloponnese. Trend analysis for SPI-1, SPI-3 and SPI-6 indicate a mixture of non-significantly increasing wetting trends and increasing drought trends at the national scale. In conclusion, the ERA5 dataset seems to be a valuable tool for drought monitoring at the spatial scale.

Spatiotemporal variation of water cycle components in Minjiang River Basin based on a correction method for evapotranspiration products

Study regionMinjiang River Basin of China. Study focusThis paper aimed to study the spatiotemporal changes in water cycle components including evapotranspiration (ET) and terrestrial water storage in a watershed. To achieve this, we proposed a method that is based on the water balance and utilizes measured annual precipitation and runoff data to correct ET products. Subsequently, we derived the annual terrestrial water storage changes and performed trend analysis on the water cycle components by the Mann-Kendall trend test. New hydrological insights for the region(1) The Global Land Data Assimilation System (GLDAS) product overestimated ET from 2000 to 2019 in the Minjiang River Basin (MJB), which was 105.18 mm higher than ET. Through sub-basin validation, the relative error between the corrected ET and the ET is less than 5.1%. The proposed method can construct a reasonable annual dataset of water cycle components. (2) From 2000–2019, the Minjiang River Basin witnessed non-significant increasing trends in precipitation and runoff. However, significant growth was observed in ET, indicated by a Mann-Kendall trend test Z-value of 2.63. The variation in ET was primarily influenced by the normalized difference vegetation index (NDVI) (correlation coefficients of 0.37) and temperature (correlation coefficients of 0.48). The terrestrial water storage change fluctuated between − 400 and 355 mm. The relationships among the water cycle components, as represented by the runoff coefficient and evapotranspiration coefficient show non-significant changing trends. Both displayed a non-significant decreasing trend. From 2000–2019, the water cycle process remained relatively stable under changing environments in the MJB.

Local and regional climate trends and variabilities in Ethiopia: Implications for climate change adaptations

Ethiopia is experiencing considerable impact of climate change and variability in the last five decades. Analyzing climate trends and variability is essential to develop effective adaptation strategies, particularly for countries vulnerable to climate change. This study analyzed trends and variabilities of climate (rainfall, maximum temperature (Tmax), and minimum temperature (Tmin)) at local and regional scales in Ethiopia. The local analysis was carried out considering each meteorological station, while the regional analyses were based on agro-ecological zones (AEZs). This study used observations from 47 rainfall and 37 temperature stations obtained from the Ethiopian Meteorological Institute (EMI) for the period of 1986 to 2020. The Modified Mann-Kendall (MMK) trend test and Theil Sen's slope estimator were used to analyze the trends and magnitudes of change, respectively, in rainfall as well as temperature. The coefficient of variation (CV) and standardized anomaly index (SAI) were also employed to evaluate rainfall and temperature variabilities. The local level analysis revealed that Bega (dry season), Kiremt (main rainy season), and annual rainfall showed increasing trend, albeit no significant, in most stations, but the rainfall in Belg (small rainy) season showed a non-significant decreasing trend. The regional levels analysis also indicated an increasing trend of Bega, Kiremt, and annual rainfall in most AEZs, while Belg rainfall showed a decreasing trend in the greater number of AEZs. The result of both local and regional levels of analysis discerned a spatially and temporally more homogeneous warming trend. Both Tmax and Tmin revealed an increasing trend in annual and seasonal scales at most meteorological stations. Likewise, an increase was recorded for mean Tmax and Tmin in entire/most AEZs. The observed trends and variabilities of rainfall and temperature have several implications for climate change adaptations. For example, the decrease in Belg rainfall in most AEZs would have a negative impact on areas that heavily depend on Belg season's rainfall for crop production. Some climate adaptation options include identifying short maturing crop varieties, soil moisture conservation, and supplemental irrigation of crops using harvested water during the main rainy season. Conversely, since the first three months of Bega season (October to December) are crop harvest season in most parts of Ethiopia, the increase in Bega rainfall would increase crop harvest loss, and hence, early planting date and identifying short maturing crops during the main rainy season are some climate adaptation strategies. Because of the increase in temperature, water demand for irrigation during Bega season will increase due to increased evapotranspiration. On the other hand, the increase in Kiremt rainfall can be harvested and used for supplemental irrigation during Bega as well as the small rainy season, particularly for early planting. In view of these findings, it is imperative to develop and implement effective climate-smart agricultural strategies specific to each agro-ecological zone (AEZ) to adapt to rainfall and temperature changes and variabilities.

Analyzing Temporal Patterns of Temperature, Precipitation, and Drought Incidents: A Comprehensive Study of Environmental Trends in the Upper Draa Basin, Morocco

Quantifying variation in precipitation and drought in the context of a changing climate is important to assess climate-induced changes and propose feasible mitigation strategies, particularly in agrarian economies. This study investigates the main characteristics and historical drought trend for the period 1980–2016 using the Standard Precipitation Index (SPI), Standard Precipitation Evaporation Index (SPEI), Run Theory and Mann–Kendall Trend Test at seven stations across the Upper Draa Basin. The results indicate that rainfall has the largest magnitude over the M’semrir and Agouim (&gt;218 mm/pa) and the lowest in the Agouilal, Mansour Eddahbi Dam, and Assaka subregions (104 mm–134 mm/pa). The annual rainfall exhibited high variability with a coefficient of variation between 35−57% and was positively related to altitude with a correlation coefficient of 0.86. However, no significant annual rainfall trend was detected for all stations. The drought analysis results showed severe drought in 1981–1984, 2000–2001, and 2013–2014, with 2001 being the driest year during the study period and over 75% of both SPEI and SPI values returned drought. Conversely, wet years were experienced in 1988–1990 and 2007–2010, with 1989 being the wettest year. The drought frequency was low (&lt;19%) across all the timescales considered for both SPI and SPEI, with Mansour Eddahbi Dam and Assaka recording the highest frequencies for SPI-3 and SPEI-3, respectively.

Abstract 18020: An Analysis of Retraction Studies in the Cardiology in Last 2 Decades

Background: False information might harm patients and increase medical care costs. For accurate and rapid scientific advancement and clinical care, the integrity of published biomedical literature is essential. Hence, we analyzed the retracted studies in cardiology. Methodology: We adhere to the STROBE checklist. This cross-sectional study utilized PubMed and Embase databases to identify retracted publications from 2002-2022. The articles are retrieved for the detailed analysis of various characteristics, including year of publication, article type, causes of retraction, impact factor, number of citations, and author country. The statistical analysis was done by using R statistical software. Fischer t-test and 2-sample t-test were used to compare the two groups. Mann-Kendall Trend Test was used to know the trend of various variables. P-value &lt;0.05 was considered significant. Results: The search yielded 979 articles. Randomized controlled studies, experimental studies, and case-control studies are major retracted study designs. Authors from China have the highest number of retracted studies (36.1%), followed by the USA (22.4%) and Japan (4%). The most common cause of retraction is mistakes and honest errors (24.51%); and duplicate data (17.78%). From 2002 to 2022, there has been an insignificant increase in the number of retracted studies with a significant decrease in the impact factor of journals, number of citations, and time to retraction. In the first decade(FD, 2003-2012) and second decade (SD, 2013-2023), males (68.2% in the FD and 66.9% in SD) had higher retraction. In the FD, USA's first authors had the highest retractions (32.5%), while in the SD, it was for Chinese authors (46%). In the SD, retracted publications had fewer citations than in the FD (mean difference (MD) -96.37, 95% CI -142.12 to -50.62, p-value &lt;0.001). Also, the SD publications have less time for retractions (MD -9.12, 95%CI -15.52 to -2.71, p-value&lt;0.005). Conclusion: The trend of retracting publications in cardiovascular diseases is increasing. The retracted studies are still cited, but there is a decreasing trend.

Ecological risk assessment of grassland vegetation change based on Bayesian model in Xilin Gol League, China

As an essential ecological barrier in the north of China, the grassland degradation situation in the Xilin Gol League of Inner Mongolia has remained severe in recent years. Based on data spanning from 2010 to 2022, this study utilizes a set of ten indicators, encompassing altitude, temperature, precipitation, wind speed, FVC, LAI, FRAR, NPP, ET, and above-ground biomass, to construct a Bayesian model for assessing ecological risks associated with vegetation change in the Xilin Gol League. In the case of the most crucial parameter, above-ground biomass, we integrate spectral bands, vegetation indices, and ground-truth data, employing the Random Forest algorithm to estimate the above-ground biomass in the Xilin Gol League. The study further applies the Mann-Kendall trend test and Sen's slope estimation to analyze changes in this parameter and employs it as an indicator for assessing grassland degradation. The results showed that (1) Overall, the risk level decreases gradually from the west to the east and aligns with the grassland types of the Xilin Gol League. (2) In terms of spatial and temporal distribution, medium and high-risk areas are primarily located in the western region of the Xilin Gol League, showing a distinct westward shift from 2010 to 2022. (3) Areas with higher grassland degradation risk are characterized by lower altitudes, higher temperatures, less precipitation, lower vegetation coverage, and reduced potential evapotranspiration. (4) Under the pressures of both climate warming and vegetation change, there has been a significant shift in grassland degradation risk levels in the Xilin Gol League. The application of the Bayesian model effectively reveals intricate causal relationships among various variables, such as climate, terrain, and vegetation dynamics. This study could provide guidance for the prevention and control of grassland degradation in the Xilin Gol League.

Examining the Spatiotemporal Changes in the Annual, Seasonal, and Daily Rainfall Climatology of Puerto Rico

This study explores spatial and temporal changes in the rainfall climatology of Puerto Rico in order to identify areas where annual, seasonal or daily precipitation is increasing, decreasing, or remaining normal. Total annual, seasonal, and daily rainfall were retrieved from 23 historical rain gauges with consistent data for the 1956–2021 period. Mann–Kendall trend tests were done on the annual and seasonal rainfall series, and percentage change differences between two different climatologies (1956–1987 and 1988–2021) were calculated. Most of the stations did not exhibit statistically significant annual or seasonal trends in average rainfall. However, of the sites that did experience changes, most of them had statistically significant decreasing trends in mean precipitation. The annual, dry, and early wet season had more sites with negative trends when compared with positive trends, especially in the northwestern and southeastern region of the island. The late wet season was the only period with more sites showing statistically significant trends when compared with negative trends, specifically in the northern region of the island. Results for daily events show that extreme rainfall occurrences have generally decreased, especially in the western region of the island. When the 1955–1987 and 1988–2022 climatologies are compared, the results for annual average rainfall show two main regions with mean precipitation reductions, and those are the northwestern and southeastern areas of the island. The dry season was the only period with more areas exhibiting percentage increases in mean rainfall when the two climatologies were analyzed. The early and late wet season months exhibited similar patterns, with more areas on the island showing negative percentage decreases in average seasonal precipitation. The best predictor for the decreasing annual and seasonal trend in the northwest was a higher sea level pressure, and the variable that best explained the increasing trend in the northeast was total precipitable water.

Healthcare lobbying and oncology.

5 Background: The healthcare industry spends more on lobbying than any other industry, with over $700 million spent in 2022. However, healthcare lobbying related specifically to cancer has not been characterized. In the current study, we analyze both overall health sector lobbying spending and oncology-related lobbying spending across both provider and patient organizations. Methods: We obtained lobbying data from OpenSecrets.org and the Federal Election Commission website. We categorized overall health sector lobbying spending as (1) Pharmaceuticals/Health Products, (2) Health Services/HMOs, (3) Hospitals/Nursing Homes, or (4) Health Professionals. We identified and categorized oncology-related lobbying organizations: (1) Oncology Physician Professional Organizations (OPOs, e.g., ASCO); (2) PPS-Exempt Cancer Hospitals; (3) Patient Advocacy Organizations; and (4) Provider Networks (e.g., US Oncology Network). We analyzed temporal trends in lobbying spending, in both overall dollar value (inflation-adjusted 2023 dollars) and in per-physician spending (using AAMC data for number of hematologists/oncologists). Significance was analyzed using a Mann-Kendall Trend Test. Results: Of overall health sector lobbying, Pharmaceuticals/Health Products had the greatest increase in lobbying spending from 2014 to 2022, with an increase from $294 million to $376 million (28%, p = 0.0006). In contrast, lobbying spending by health professionals did not change over this period, remaining at $96 million (p = 0.35). Regarding oncology-related lobbying, per-physician spending by OPOs and PPS-exempt cancer hospitals increased (Table). Overall, OPO lobbying has increased as a percentage of overall physician lobbying from 1.16% in 2014 to 3.76% in 2022 (not shown). Conclusions: While overall health sector lobbying spending by physicians/health professional lobbying has been relatively stable in recent years, lobbying spending by OPOs has increased. Continued efforts to understand the utility and value of lobbying in healthcare and across oncology are needed as the costs of care continue to rise. [Table: see text]

Quantitative Analysis of the Impact of Climate Change and Human Activities on Runoff Variation in Akwa Ibom State, Nigeria

The non-parametric Mann-Kendall (MK) trend test, including the Sen's slope test and Pettitt's test, was used to determine trends, magnitudes, and change points in hydro-meteorological variables from 1972 to 2021. The slope change ratio of accumulative quantity (SCRAQ) method was then used to calculate the relative contributions of climate change and human activities to runoff variation in the Uyo-Itu river basin. Annual rainfall, maximum temperature, minimum temperature, and runoff showed significant increasing trends, whereas annual relative humidity, solar radiation, and potential evapotranspiration showed significant decreasing trends. Between 1992 and 2010, there were abrupt changes in hydro-meteorological variables. However, the runoff shift occurred in 2003. The time period under consideration was divided into two parts: baseline period A and change (impacted) period B. Climate change dominates runoff variation in period B, accounting for 103.6 percent of the variation, while human activities have a negative impact (-3.6%). The results indicate that climate change is the primary driver of runoff variation and that its impact is becoming more severe. Furthermore, the Budyko hypothesis was used to validate the contributions of human activities and climatic changes based on the SCRAQ method. The results showed that the contributions of human activities and climatic changes computed using the SCRAQ method are comparable with those computed using the sensitivity-based method. From this study, it can be concluded that assessing the influence of climate changes and human activities on variations and identifying the major driving forces causing the variations are critical for more efficient water resources management for sustainable economic growth&#x0D;

Mechanistic interaction between climate variables rainfall and temperature on surface water quality and water treatment costs at the Barekese Headworks, Ghana: A time series analysis and water quality index modelling approach

Extreme rainfall and temperatures are climate variables that threaten global water supplies and surface water quality (SWQ). To understand how rainfall and temperature interact with surface water quality and water treatment costs, this study, unlike previous ones, uses time series analysis (TSA) and water quality index (WQI) modelling to fill significant research gaps. The study uses data from the Barekese Water Treatment Headworks, Ghana. Water quality data from 2000 to 2019 for the Barekese Headworks were obtained from the Ghana Water Company Limited. Rainfall data for the catchment was obtained from the Ghana Meteorological Agency. The Mann-Kendall statistical test for trend and the Canadian Council of Ministers of the Environment (CCME) water quality index was applied to data sets. The Mann-Kendall trend test showed no significant change in annual temperatures. An increasing trend for annual rainfall was observed, but this was not statistically significant (Z = 0.21). Sen's slope estimator (Q) showed that rainfall increases at 3.03 mm annually. pH correlated negatively with rainfall (r = - 0.15). Correlations were observed between rainfall and temperature and dissolved oxygen (DO), turbidity, Total Dissolved Solids (TDS), Nitrate (NO3−), Phosphate (PO43−), and Manganese (Mn). Rainfall was observed to increase the cost of liming, coagulation, and disinfection. A 20.26% deterioration in SWQ was observed from 2009 to 2019. The SWQ over the period under study and according to the CCME water quality index was 80% marginal, 10% fair and 10% poor. The findings reveal that the concurrent use of TSA and WQI modelling can help elucidate how rainfall and temperature interact with SWQ and water treatment costs. It further contributes knowledge to attaining the Africa Union Agenda 2063 on climate resilience and the Sustainable Development Goals (SDG) 6 and 6.3 on universal water access and quality improvement.

Historical (1960–2014) lightning and LNOx trends and their controlling factors in a chemistry–climate model

Abstract. Lightning can cause natural hazards that result in human and animal injuries and fatalities, infrastructure destruction, and wildfire ignition. Lightning-produced NOx (LNOx), a major NOx (NOx=NO+NO2) source, plays a vital role in atmospheric chemistry and global climate. The Earth has experienced marked global warming and changes in aerosol and aerosol precursor emissions (AeroPEs) since the 1960s. Investigating long-term historical (1960–2014) lightning and LNOx trends can provide important indicators for all lightning-related phenomena and for LNOx effects on atmospheric chemistry and global climate. Understanding how global warming and changes in AeroPEs influence historical lightning and LNOx trends can be helpful in providing a scientific basis for assessing future lightning and LNOx trends. Moreover, global lightning activities' responses to large volcanic eruptions such as the 1991 Pinatubo eruption are not well elucidated and are worth exploring. This study employed the widely used cloud top height lightning scheme (CTH scheme) and the newly developed ice-based ECMWF-McCAUL lightning scheme to investigate historical (1960–2014) lightning and LNOx trends and variations as well as their influencing factors (global warming, increases in AeroPEs, and the Pinatubo eruption) in the framework of the CHASER (MIROC) chemistry–climate model. The results of the sensitivity experiments indicate that both lightning schemes simulated almost flat global mean lightning flash rate anomaly trends during 1960–2014 in CHASER (the Mann–Kendall trend test (significance inferred as 5 %) shows no trend for the ECMWF-McCAUL scheme, but a 0.03 % yr−1 significant increasing trend is detected for the CTH scheme). Moreover, both lightning schemes suggest that past global warming enhances historical trends for global mean lightning density and global LNOx emissions in a positive direction (around 0.03 % yr−1 or 3 % K−1). However, past increases in AeroPEs exert an opposite effect on the lightning and LNOx trends (−0.07 % to −0.04 % yr−1 for lightning and −0.08 % to −0.03 % yr−1 for LNOx) when one considers only the aerosol radiative effects in the cumulus convection scheme. Additionally, effects of past global warming and increases in AeroPEs in lightning trends were found to be heterogeneous across different regions when analyzing lightning trends on the global map. Lastly, this paper is the first of study results suggesting that global lightning activities were markedly suppressed during the first year after the Pinatubo eruption as shown in both lightning schemes (global lightning activities decreased by as much as 18.10 % as simulated by the ECMWF-McCAUL scheme). Based on the simulated suppressed lightning activities after the Pinatubo eruption, the findings also indicate that global LNOx emissions decreased after the 2- to 3-year Pinatubo eruption (1.99 %–8.47 % for the annual percentage reduction). Model intercomparisons of lightning flash rate trends and variations between our study (CHASER) and other Coupled Model Intercomparison Project Phase 6 (CMIP6) models indicate great uncertainties in historical (1960–2014) global lightning trend simulations. Such uncertainties must be investigated further.

Long‐term trend analysis in annual, seasonal and monthly rainfall in East Northeast of Brazil and the influence of modes of climate variability

AbstractThe study of rainfall trends is crucial for food security and water availability in Alagoas state, Northeast of Brazil. In this work, monthly, seasonal and annual rainfall trends have been studied (1960–2016) for homogeneous rainfall regions over the eastern part of the Northeast Brazil (ENEB) and later related to climate variability. Cluster analysis was applied to identify homogeneous rainfall regions while the Mann–Kendall (MK), modified Mann–Kendall (MMK) and Pettitt tests were used in the analysis and identification of trends on a spatial and temporal scale. To relate rainfall and climate variability modes, Spearman's correlation was used in each homogeneous region. The rainfall series provided evidence of a general decrease in rainfall in the rainy period and an increase in the dry period, mainly over the driest region. The break points of time series occurred mostly in periods of great variations in values of modes of climate variability, especially the Monthly Niño3.4 Index and the Southern Oscillation Index (SOI), both having a robust influence across the region. Moreover, the probable rainfall in the time series with trends was different in most months before and after the breakpoint. After the breakpoint, probable rainfall was lower, influenced by the breakpoint year (size of the series before and after the breakpoint), which mainly occurred in the 1980s and 1990s and presented a warm phase and a greater number of El Niño events. The MK and MMK trend tests showed the ability to detect trends, although there is no established standard on which test or version to use due to self‐correlated, nonhomogeneous series with nonrandom or nonindependent data. Rainfall is an important variable for water and food security and in the monitoring of natural disasters. The changes detected in this study can be used as reference information for public policies on water resources and future studies for Alagoas and similar regions.

Short-term restoration effects of ecological projects detected using the turning point method in the Three River Headwater Region, China.

The Three River Headwater Region (TRHR) is an important river source area providing important ecological functions. Decades ago, climate change and human activities severely degraded the ecosystem in the TRHR. To restore vegetation, a series of ecological projects have been implemented since 1989. Using net primary productivity (NPP) data from 1988 to 2012, a sequential Mann-Kendall trend test (SQ-MK) method was applied to identify the turning point of vegetation NPP. This approach was able to represent the critical response time of the vegetation to important disturbances. A 3-year time window was set after the implementation of one ecological project to detect and analyze its short-term effects. The ecological projects included the Yangtze River Basin Shelterbelt System Construction Project (YRCP), the TRHR Nature Reserve Construction Project (TNR), the Returning Grazing Land to Grassland Project (RGLGP), and the first phase of the Ecological Conservation and Restoration Project of the TRHR (ECRP). Our results showed that the vegetation in the TRHR responded positively to restoration: 89% of pixels showed an increasing trend and 54% of pixels underwent an abrupt change. The accelerated growth type accounted for the highest proportion among all types of detected turning points. In the ECRP's window, the positive turns rose rapidly, from 41% in 2005 to 86% in 2008, and it showed the most balanced restoration effects across grasslands. The alpine meadow and montane meadow restoration was largely influenced by the ECRP and the RGLGP (both >40%). The alpine steppe restoration was mainly attributed to the ECRP (68%). On the county scale, the positive turns in Yushu at the source of the Yangtze River mainly benefited from the RGLGP (56%), while the positive turns in Maduo at the source of the Yellow River benefited from the ECRP (77%). Nangqian, Tanggula and Zaduo County were still in need of intervention for restoration (< 3%). The results of the study can enhance our understanding of the spatio-temporal distribution of the short-term ecological benefits of different ecological projects, thus provide a scientific and timely reference for future planning and adjustment of the conservation and restoration projects.

Spatial-temporal characteristics of more than 50,000 wildfires in Japan from 1995 to 2020

The spatial-temporal characteristics of wildfires were summarized based on fire reports covering 55,863 wildfires with a total burned area of 289.91 km2 from 1995 to 2020 in Japan. The long-term decreasing trend was largely influenced by changes in social aspects, while the annual fluctuation was determined by large-scale events. The wildfire season started around early January in the southern part and gradually shifted northward over approximately three months. A total of 98.77% of cases were human-induced, and 1.23% were caused by lightning. Regarding response time after receiving the call, firefighting was started within 30 min in 89% of cases and controlled within 1 h in 85% of cases, where spatial characteristics were insignificant. Full-time fire departments utilized artificial water sources primarily in 72% of cases and natural water sources in 28%, while the rate using natural water sources increased as the burned area increased. Natural water sources from ponds and rivers exhibited regionalities. Cluster analysis revealed five wildfire regions reflecting natural and anthropogenic factors. Furthermore, the Mann–Kendall trend test concluded that the initiation process decreased almost uniformly across the country, while regional differences existed regarding the expansion process. Additionally, only human-induced wildfires had a significant decreasing trend.