Typhoon-induced stormwater drives nutrient dynamics and triggers phytoplankton blooms in Laizhou Bay, China.

In this study, we investigated the hydrological and ecological impacts of heavy rainfall caused by the storm Rumbia and Typhoon Lekima on Laizhou Bay (LZB) through land‒sea synchronous field surveys, online remote sensors, and simulated enclosure experiments. Within two weeks of Rumbia, approximately 9% and 16% of the annual riverine total nitrogen (TN) and total phosphorus (TP) fluxes, respectively, were transported to the LZB and the proportions were 17% and 35%, respectively, for Lekima. The land use on the watersheds increased the rates of land-derived nutrient loading and altered their biogeochemical forms. Consequently, the average concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) in the LZB increased by 2.6 and 1.0 times post-Rumbia and by 3.5 and 1.3 times post-Lekima, respectively. Relatively lower salinity and temperature, sudden increases in DIN, and strengthened coastal currents stimulated the growth of highly adaptable and small diatoms, resulting in the first diatom blooms. Subsequently, a bloom of Noctiluca scintillans formed.

Appling fluorescence spectroscopy with absolute principal component coefficient to explore dynamic migration of DOM fractions from an urbanized river during torrential rainfall.

This research delves into the dynamic interplay between urbanization and the characteristics of Dissolved Organic Matter (DOM) in the Anyang River, particularly under the stress of torrential rain. The motivation stems from a critical need to decipher how urban landscapes influence water quality, focusing on the intricate transformations and movements of DOM. Employing advanced fluorescence spectroscopy techniques like Excitation-Emission Matrices (EEM) and Parallel Factor Analysis (PARAFAC), the study meticulously differentiates DOM compositions in urban and agricultural settings. It unveils a pronounced distinction, with urban streams showing elevated proteinaceous DOM from wastewater, contrasting with the humic substances prevalent in agricultural runoff. The analysis also captures how intense rainfall events catalyze significant shifts in DOM profiles, thereby emphasizing the need for tailored water quality management strategies in urbanized catchments. This comprehensive approach not only bridges gaps in understanding the urban impact on riverine ecosystems but also sets a foundation for future research and policy development in the face of escalating environmental changes.

Exposure of protected areas in Central America to extreme weather events.

Central America and the Caribbean are regularly battered by megadroughts, heavy rainfall, heat waves, and tropical cyclones. Although 21st-century climate change is expected to increase the frequency, intensity, and duration of these extreme weather events (EWEs), their incidence in regional protected areas (PAs) remains poorly explored. We examined historical and projected EWEs across the region based on 32 metrics that describe distinct dimensions (i.e., intensity, duration, and frequency) of heat waves, cyclones, droughts, and rainfall and compared trends in PAs with trends in unprotected lands. From the early 21st century onward, exposure to EWEs increased across the region, and PAs were predicted to be more exposed to climate extremes than unprotected areas (as shown by autoregressive model coefficients at p < 0.05 significance level). This was particularly true for heat waves, which were projected to have a significantly higher average (tested by Wilcoxon tests at p < 0.01) intensity and duration, and tropical cyclones, which affected PAs more severely in carbon-intensive scenarios. PAs were also predicted to be significantly less exposed to droughts and heavy rainfall than unprotected areas (tested by Wilcoxon tests at p < 0.01). However, droughts that could threaten connectivity between PAs are increasingly common in this region. We estimated that approximately 65% of the study area will experience at least one drought episode that is more intense and longer lasting than previous droughts. Collectively, our results highlight that new conservation strategies adapted to threats associated with EWEs need to be tailored and implemented promptly. Unless urgent action is taken, significant damage may be inflicted on the unique biodiversity of the region.

Ciclones, olas de calor, sequías y lluvias intensas son eventos comunes en Centroamérica y el Caribe, cuya frecuencia, intensidad y duración se espera aumente durante el siglo XXI a causa del cambio climático. Sin embargo, en la actualidad, se desconoce cuál será la incidencia de estos eventos meteorológicos extremos (EME) dentro de las áreas protegidas. En este estudio examinamos la exposición histórica y futura a los extremos climáticos y comparamos el grado de exposición dentro y fuera de las áreas protegidas de toda la región por medio de 32 métricas que describen distintas dimensiones (intensidad, duración y frecuencia) de las olas de calor, los ciclones, las sequías y las precipitaciones. Los resultados indican que a medida que aumente el número de EME, las áreas protegidas estarán más expuestas a los extremos climáticos que las áreas no protegidas. Esto es especialmente cierto en el caso de las olas de calor, que, según las proyecciones, tendrán una intensidad y una duración medias significativamente mayores, y de los ciclones tropicales, que afectarán más gravemente a las zonas protegidas en los escenarios intensivos en carbono. Nuestros resultados también indican que las zonas protegidas estarán significativamente menos expuestas a sequías o lluvias torrenciales que las zonas no protegidas. Sin embargo, las sequías que podrían amenazar la conectividad entre áreas protegidas son cada vez más frecuentes en esta región. Se estima que aproximadamente el 65% del área de estudio experimentará al menos un episodio de sequía más intenso y duradero que las sequías anteriores. En conjunto, nuestros resultados ponen de relieve la necesidad de diseñar y aplicar con prontitud nuevas estrategias de conservación adaptadas a las amenazas asociadas a los EWE. A menos que se tomen medidas urgentes, la biodiversidad única de la región podría sufrir daños considerables.

Spatial-Temporal Dynamic Evolution of Land Deformation Driven by Hydrological Signals around Chaohu Lake.

The frequent occurrence of extreme climate events has a significant impact on people's lives. Heavy rainfall can lead to an increase of regional Terrestrial Water Storage (TWS), which will cause land subsidence due to the influence of hydrological load. At present, regional TWS is mostly obtained from Gravity Recovery and Climate Experiment (GRACE) data, but the method has limitations for small areas. This paper used water level and flow data as hydrological signals to study the land subsidence caused by heavy rainfall in the Chaohu Lake area of East China (June 2016-August 2016). Pearson's correlation coefficient was used to study the interconnection between water resource changes and Global Navigation Satellites System (GNSS) vertical displacement. Meanwhile, to address the reliability of the research results, combined with the Coefficient of determination method, the research findings were validated by using different institutional models. The results showed that: (1) During heavy rainfall, the vertical displacement caused by atmospheric load was larger than non-tidal oceanic load, and the influence trends of the two were opposite. (2) The rapidly increasing hydrologic load in the Chaohu Lake area resulted in greater subsidence displacement at the closer CORS station (CHCH station) than the more distant CORS station (LALA station). The Pearson correlation coefficients between the vertical displacement and water level were as high as -0.80 and -0.64, respectively. The phenomenon confirmed the elastic deformation principle of disc load. (3) Although there was a systematic bias between the different environmental load deformation models, the deformation trends were generally consistent with the GNSS monitoring results. The average Coefficients of determination between the different models and the GNSS results were 0.63 and 0.77, respectively. The results demonstrated the effectiveness of GNSS in monitoring short-term hydrological load. This study reveals the spatial-temporal evolution of land deformation during heavy rainfall around Chaohu Lake, which is of reference significance for water resource management and infrastructure maintenance in this area.

Response mechanism of soil leachate and disinfection by-product formation to extreme precipitation events under continuous drought scenario.

In this study, a rainfall simulation device was employed to investigate the response mechanism of soil leachate and disinfection by-products formation potential (DBPsFP) to extreme precipitation events. The results revealed that the aromaticity of dissolved organic matter (DOM) and the concentration of hydrophobic DOM containing aromatic carbon groups in leachate decreased with rising temperature. The humification degree of DOM decreased at 25 °C (99 mm/h), while the humification degree and protein-like level of DOM increased under high temperatures droughts (45 °C and 65 °C). Higher temperatures resulted in the leach of more microbial-derived humus and low molecular phenolic compounds from soil and broadened the range of molecular weight distribution. Increasing temperature increased DBPsFP and DBPs species and caused the precursors of haloacetic acids (HAAs) in leachate to become more hydrophobic, while the precursors of trihalomethanes (THMs) became more hydrophilic. Most importantly, the increased temperature attenuated the rainfall-mediated dilution of organic pollutant concentration, and temperature has a more significant effect than extreme rainfall in DOM abundance and the formation potential (or species) of DBPs. The results help to better understand the impact of climate change on the physicochemical processes of water quality.

Prior water availability modifies the effect of heavy rainfall on dengue transmission: a time series analysis of passive surveillance data from southern China.

Introduction: Given the rapid geographic spread of dengue and the growing frequency and intensity of heavy rainfall events, it is imperative to understand the relationship between these phenomena in order to propose effective interventions. However, studies exploring the association between heavy rainfall and dengue infection risk have reached conflicting conclusions, potentially due to the neglect of prior water availability in mosquito breeding sites as an effect modifier. Methods: In this study, we addressed this research gap by considering the impact of prior water availability for the first time. We measured prior water availability as the cumulative precipitation over the preceding 8 weeks and utilized a distributed lag non-linear model stratified by the level of prior water availability to examine the association between dengue infection risk and heavy rainfall in Guangzhou, a dengue transmission hotspot in southern China. Results: Our findings suggest that the effects of heavy rainfall are likely to be modified by prior water availability. A 24-55 day lagged impact of heavy rainfall was associated with an increase in dengue risk when prior water availability was low, with the greatest incidence rate ratio (IRR) of 1.37 [95% credible interval (CI): 1.02-1.83] occurring at a lag of 27 days. In contrast, a heavy rainfall lag of 7-121 days decreased dengue risk when prior water availability was high, with the lowest IRR of 0.59 (95% CI: 0.43-0.79), occurring at a lag of 45 days. Discussion: These findings may help to reconcile the inconsistent conclusions reached by previous studies and improve our understanding of the complex relationship between heavy rainfall and dengue infection risk.

Assessment of weather events impacts on forage production trend of sorghum-sudangrass hybrid.

This study aimed to assess the impact of weather events on the sorghum-sudangrass hybrid (Sorghum bicolor L.) cultivar production trend in the central inland region of Korea during the monsoon season, using time series analysis. The sorghum-sudangrass production data collected between 1988 and 2013 were compiled along with the production year's weather data. The growing degree days (GDD), accumulated rainfall, and sunshine duration were used to assess their impacts on forage production (kg/ha) trend. Conversely, GDD and accumulated rainfall had positive and negative effects on the trend of forage production, respectively. Meanwhile, weather events such as heavy rainfall and typhoon were also collected based on weather warnings as weather events in the Korean monsoon season. The impact of weather events did not affect forage production, even with the increasing frequency and intensity of heavy rainfall. Therefore, the trend of forage production for the sorghum-sudangrass hybrid was forecasted to slightly increase until 2045. The predicted forage production in 2045 will be 14,926 ± 6,657 kg/ha. It is likely that the damage by heavy rainfall and typhoons can be reduced through more frequent harvest against short-term single damage and a deeper extension of the root system against soil erosion and lodging. Therefore, in an environment that is rapidly changing due to climate change and extreme/abnormal weather, the cultivation of the sorghum-sudangrass hybrid would be advantageous in securing stable and robust forage production. Through this study, we propose the cultivation of sorghum-sudangrass hybrid as one of the alternative summer forage options to achieve stable forage production during the dynamically changing monsoon, in spite of rather lower nutrient value than that of maize (Zea mays L.).

Prior water availability modifies the effect of heavy rainfall on dengue transmission: a time series analysis of passive surveillance data from southern China.

Background: Given the rapid geographic spread of dengue and the growing frequency and intensity of heavy rainfall events, it is imperative to understand the relationship between these phenomena in order to propose effective interventions. However, studies exploring the association between heavy rainfall and dengue infection risk have reached conflicting conclusions. Methods: In this study, we use a distributed lag non-linear model to examine the association between dengue infection risk and heavy rainfall in Guangzhou, a dengue transmission hotspot in southern China, stratified by prior water availability. Results: Our findings suggest that the effects of heavy rainfall are likely to be modified by prior water availability. A 24-55 day lagged impact of heavy rainfall was associated with an increase in dengue risk when prior water availability was low, with the greatest incidence rate ratio (IRR) of 1.37 (95% credible interval (CI): 1.02-1.83) occurring at a lag of 27 days. In contrast, a heavy rainfall lag of 7-121 days decreased dengue risk when prior water availability was high, with the lowest IRR of 0.59 (95% CI: 0.43-0.79), occurring at a lag of 45 days. Conclusions: These findings may help to reconcile the inconsistent conclusions reached by previous studies and improve our understanding of the complex relationship between heavy rainfall and dengue infection risk.

Response of prokaryotic, eukaryotic and algal communities to heavy rainfall in a reservoir supplied with reclaimed water.

The global climate change made the heavy rainfall happen more frequently, and the non-point source pollution caused by it would exacerbate the risk to the water ecological environment. In this study, we took a reservoir (Shahe reservoir, Beijing, China) supplied with reclaimed water as an exapmle to investigate how spatiotemporal changes in the quantity and diversity of prokaryotic, eukaryotic, and algal communities respond to heavy rainfall. Results showed that heavy rainfall could directly impact the composition of the prokaryotic community by introducing amounts of runoff closely associated bacterium especially for the human potential pathogens such as Aliarcobacter, Aeromonas and Pseudomonas in the Shahe reservoir area. While the eukaryotic community was rather stable, and the development and changes in algal communities occurred in the last few days after heavy rainfall. The microbial source tracking through FEAST indicated that Nansha river (S) was the major contributor to the development of all the three concerned communities in the reservoir. The co-occurrence analysis showed that the modules with the highest cumulative abundance in each community were all strongly and positively connected with Chl-a, pH, turbidity, COD and TOC, but negatively correlated with NO3-N (p < 0.01). The network analysis showed that the eukaryotes played a key role in the interaction network among the three communities, and were more likely to interact with algae and prokaryotes. It was suggested that the controlling of human potential pathogens associated with prokaryotic community should be emphasized at the beginning of the heavy rainfall, but the prevention of the eutrophication bloom should be another focus after the heavy rainfall. This study provided valuable information concerning the role of heavy rainfall on the water ecological environment from the perspective of microbial community.

The Impact of Heavy Rainfall Variability on Fertilizer Application Rates: Evidence from Maize Farmers in China.

Global warming increases the intensity and frequency of extreme weather events, which is harmful to agricultural production. Given that the overuse of fertilizer has been found to be a significant contributor to global warming, it is crucial to analyze the factors affecting farmers' fertilizer use and find appropriate fertilizer reduction measures. Agriculture is inherently risky, but previous studies have ignored the risk factors related to heavy rainfall variability, including fertilizer losses and the possible yield risks, which may lead to income risk. Using the 1995-2018 National Rural Fixed Observation Point Survey Data, this study examines the impact of heavy rainfall variability on maize farmers' fertilizer application rates, aiming to understand farmers' fertilization behavior in response to weather shocks. The results show that heavy rainfall variability significantly increases farmers' fertilizer application rates on maize. Furthermore, we find that heavy rainfall variability has greater effects on fertilizer use in hills and mountainous areas and areas with good irrigation conditions or high economic levels. When examining the potential channels underlying the estimated effects, we find that yield fluctuations are a channel through which heavy rainfall variability affects farmers' fertilizer use on maize. The above results indicate that farmers view applying extra fertilizer as a risk reducing activity in response to rainfall shocks, which helps to prevent low yield and income. Strengthening agricultural infrastructure construction according to local conditions and promoting fertilizer reduction technologies and products to reduce yield risk caused by heavy rainfall can help alleviate the problem of high fertilizer application rates by Chinese farmers.

The Influence of Short-Term Heavy Rainfall on Hydraulic Characteristics and Rill Formation in the Yuanmou Dry-Hot Valley.

Rill erosion is one of the major environmental problems in the world; it is an important factor with regard to land degradation and has a serious impact on production and daily life in the region. The widely distributed Yuanmou group stratum promotes the development of rill erosion, whereby the strong time-concentrated rainfall and the alternating arid-humid climate prepare the ground for the development of rills in soils. Therefore, a study of the processes of slope rill erosion was carried out, and a gravel-soil slope in the Yuanmou dry-hot valley was chosen to simulate short-term heavy rainfall (25 mm/h) (No. 1 plot) and moderate rainfall (15 mm/h) (No. 2 plot), to study the erosion processes of soil and the dynamic characteristics of runoff involved in erosion. The study results showed that the width of runoff was significantly different between the two plots, while the depth of runoff was not significantly different. During the rill formation process, the width of the two plots first decreased and then increased with increasing washout duration, while its depth did not change significantly. Flow was the key factor in determining the hydraulic characteristics of runoff, and it had a significant or extremely significant positive correlation with hydraulic characteristics parameters, except in the case of Fr (Froude number) (r = 0.039). The total sediment content (CS) of plot No. 1 (0.158 g/cm3) was significantly different from that of plot No. 2 (0.153 g/cm3), and both CSs in the two plots decreased with increasing washout duration. The CS had an extremely significant negative correlation with τ (runoff shear force) (r = -0.863 **) and DW-f (Darcy-Weisbach drag coefficient) (r = -0.863 **) and a significant negative correlation with Re (Reynolds number) (r = -0.735 *) in the short-term heavy rainfall experiment, while the CS had a significant positive correlation with V (velocity) (r = 0.814 *), R (hydraulic radius) (r = 0.811 *) and P (unit stream power) (r = 0.811 *) in the moderate rainfall experiment. The results of this study will help guide further examination of the processes involved in the dynamic mechanisms of rill erosion on slopes under short-term heavy rainfall conditions.

Heavy Rainfall, Sewer Overflows, and Salmonellosis in Black Skimmers (Rynchops niger).

Extreme weather events, particularly heavy rainfall, are occurring at greater frequency with climate change. Although adverse human health effects from heavy rainfall are often publicized, impacts to free-ranging wildlife populations are less well known. We first summarize documented associations of heavy rainfall on wildlife health. We then report a novel investigation of a salmonellosis outbreak in a colony of black skimmers (Rynchops niger) in Florida, USA. During June-September 2016, heavy rainfall resulted in the discharge of millions of gallons of untreated wastewater into the Tampa Bay system, contaminating the water body, where adult skimmers foraged. At least 48 fledglings died, comprising 39% of the colony's nesting season's offspring. Of eight examined deceased birds from the colony, six had a systemic salmonellosis infection. Isolates were identified as Salmonella enterica serotype Typhimurium. Their pulsed-field gel electrophoresis patterns were identical to each other and matched those from several human Salmonella sp. infections. Differences among whole-genome sequences were negligible. These findings and the outbreak's epidemic curve suggest propagated transmission occurred within the colony. A multidisciplinary and One Health approach is recommended to mitigate any adverse effects of climate change-driven stochastic events, especially when they place already imperiled wildlife at further risk.

13C assimilation as well as functional gene abundance and expression elucidate the biodegradation of glyphosate in a field experiment.

Glyphosate (N-phosphonomethylglycine; GLP) and its main metabolite AMPA (aminomethylphosphonic acid), are frequently detected in relatively high concentrations in European agricultural topsoils. Glyphosate has a high sorption affinity, yet it can be detected occasionally in groundwater. We hypothesized that shrinkage cracks occurring after dry periods could facilitate GLP transport to greater depths where subsoil conditions slow further microbial degradation. To test this hypothesis, we simulated a heavy rainfall event (HRE) on a clay-rich arable soil. We applied 2.1 kg ha-1 of 100% 13C3, 15N-labeled GLP one day before the simulated rainfall event. Microbial degradation of translocated GLP over a 21-day period was assessed by quantifying 13C incorporation into phospholipid fatty acids. Microbial degradation potential and activity were determined by quantifying the abundance and expression of functional genes involved in the two known degradation pathways of GLP; to AMPA (goxA) or sarcosine (sarc). We confirmed that goxA transcripts were elevated in the range of 4.23 x 105 copy numbers g-1 soil only one day after application. The increase in AMPA associated with a rise in goxA transcripts and goxA-harboring microorganisms indicated that the degradation pathway to AMPA dominated. Based on 13C-enrichment 3 h after the HRE, fungi appeared to initiate glyphosate degradation. At later time points, Gram+-bacteria proved to be the main degraders due to their higher 13C-incorporation. Once GLP reached the subsoil, degradation continued but more slowly. By comparing GLP distribution and its microbial degradation in macropores and in the bulk soil, we demonstrated different time- and depth-dependent GLP degradation dynamics in macropores. This indicates the need for field studies in which soil properties relevant to GLP degradation are related to limiting environmental conditions, providing a realistic assessment of GLP fate in soils.

Source tracing and chemical weathering implications of strontium in agricultural basin in Thailand during flood season: A combined hydrochemical approach and strontium isotope.

87Sr/86Sr of river water are of great significance in constraining oceanic strontium (Sr) record and terrestrial climate change due to the connection of continental weathering and the adjacent ocean. This work presents the geochemical characteristics of dissolved Sr and hydrochemistry, and estimates chemical weathering rate together with elemental Sr flux during the flood season of the Mun River, the largest tributary of Mekong River. Hydrochemistry analysis indicates the dominance of Cl- and HCO3- for major anions with the average of 34.6 and 43.0 mg/L, respectively, and Na+ and Ca2+ together dominated the cationic composition with the average of 22.9 and 10.5 mg/L, respectively. The ion concentrations during flood season were lower than that in dry season, implying tremendous river runoff due to extreme rainfall. The dissolved Sr ranges 6.1-237.5 µg/L with higher contents in the upper Mun. Sr contents in flood season are lower and less fluctuated than that in dry season, whereas the divergence between up and downstream becomes larger. 87Sr/86Sr ranges 0.7100-0.7597, slightly higher than global average. Elemental molar ratio analysis partly corroborates the inference from correlation analysis, but 87Sr/86Sr does not correlate with Na/Ca, indicating additional influence except for the weathering of evaporites and silicates. Comparing to regional wastewater and rainwater, the lower reaches exhibits superimposed impact of agricultural inputs on weathering to dissolved loads, especially in downstream with more tributary convergence. Extreme rainfall during flood season and extensive agricultural production activities may interfere in altering riverine solutes. Silicate weathering rate and CO2 consumption rate are calculated as well as the yearly 87Sr in excess to the Mekong River and finally to the Pacific Ocean with a Sr flux of 1.98 × 103 tons/year, indicating significant influence on seawater strontium isotope evolution in the long run. Together with tropical climate and high-intensity precipitation, the accelerated chemical weathering process seems inevitable. Therefore, the impact of agricultural interference in the pan-Mekong River basin needs more systematic and multi-angle research to provide a comprehensive insight on better watershed management under tropical climatic conditions.

Temporal variability of 137Cs concentrations in coastal sediments off Fukushima.

Large amounts of radiocesium were released into marine environments following the Fukushima Daiichi Nuclear Power Plant accident in March 2011. Released radiocesium influenced not only marine environment but also marine biota in Fukushima. Since marine biota as fisheries products is important for Japanese market, it is important to assess the distribution of radiocesium in coastal environment off Fukushima for safety concerns of radioactive contamination. Radiocesium concentrations in sediments are important for understanding fishing ground conditions and for proving the safety of fisheries products in Fukushima. In this study, monthly monitoring data collected from May 2011 to March 2020 were analyzed to describe the temporal variability of 137Cs concentrations in coastal sediments off Fukushima (total of 3647 samples from eight lines at depths of 7-125 m off Fukushima, and three sites in Matsukawa-ura Lagoon). The 137Cs concentration in sediment showed a decreasing trend, but our nonlinear model fitting suggested that this rate of decrease had slowed down. Additionally, 137Cs concentrations were up to 4.08 times greater in shallow sampling sites (7, 10, 20 m depth) following heavy rainfall events (before five months vs. after five months), such as typhoons. These observations were consistent with increasing input from particulate 137Cs fluxes from rivers and increasing dissolved 137Cs concentrations in seawater. Finally, our numerical modeling suggested that riverine 137Cs input could maintain 137Cs concentrations in coastal sediment. These results indicate that riverine 137Cs input following heavy rainfall events is the main factor for maintaining 137Cs concentrations in coastal sediments near the Fukushima Daiichi Nuclear Power Plant.

A possible linkage of Eurasian heat wave and East Asian heavy rainfall in Relation to the Rapid Arctic warming.

In June-July 2020 two remarkable weather events occurred in northern Eurasia. One is a severe heat wave that produced a record-breaking temperature of 38 °C at Verkhoyansk, eastern Siberia on 20 June. The other one is heavy rainfall events observed in East Asia (southern China and southwestern Japan) in early July, causing severe floods that brought about considerable damage to infrastructure and the economy, as well as the loss of human lives. Despite the accumulated evidence of stronger and more extreme heat waves and heavy rainfall as a result of global warming, little is known about the linkage between these phenomena. Given that the Arctic is warming twice as fast as the global mean, Arctic warming might be enhancing the increase of heavy rainfall events in East Asia. Here, we investigated the relationship between the Siberian heat wave and the East Asian heavy rainfall that occurred summer in 2020. An empirical orthogonal function (EOF) analysis applied to atmospheric reanalysis data of 1958-2020 period captures dominant summer circulation patterns reflecting atmospheric internal variability and externally forced anomalies. On the basis of these EOF patterns, operational forecasts of summer 2020 using the global model from the Japan Meteorological Agency (JMA) and a global climate model experiment based on 2-K warming future projection are utilized to examine roles of the internal variability and external forcing, respectively. Consistent results between them reveal that development of the blocking high over eastern Siberia has certain impacts on rainfall anomalies over East Asia. By a statistical technique applied to the ensemble forecast data, prediction of the East Asian precipitation is improved by 10-20% of its amplitude. Our research demonstrates possibility that East Asian rainfall is being enhanced by high-latitude atmospheric circulations due to the Arctic warming even in the current climate in which the tropical warming is not yet severe. Suggestions are given that continued Arctic warming and a future increase of tropical warming will lead to increases of the frequency and severity of heavy rainfall events in East Asia.

The role of seagrass meadows in the coastal trapping of litter.

The accelerated discard and mismanagement of human-made products are resulting in the continued input of litter into the oceans. Models and field observations show how floating litter can accumulate in remote areas throughout the global ocean, but far less is known about the non-floating litter fraction. Seagrass meadows play an important role in the sediment and natural-debris dynamics, and likely also in the storage and processing of non-floating litter. In this work, non-floating litter was studied across six Posidonia oceanica meadows. Litter accumulated mainly around the landside edge of the meadow. The outer margin of the edge predominantly trapped macro-litter, whilst microplastics accumulated mainly along the inner margin. On average, macro-litter concentrations increased 3-fold after heavy rainfall. Retention of non-floating litter by coastal meadows facilitates the recurrent landward-seaward conveyance of the easily-transportable litter (mainly plastic items) and its fragmentation before it is buried or transferred to deeper areas.

Can nudges save lives?

To assess the promotion of life saving behaviors and determine the sustainability of nudge message effects, this paper examines nudges that promote evacuation during heavy rainfall, preventative COVID-19 infection behaviors, and COVID-19 vaccination. The results showed that altruistic gain messages may have more sustained effects than others in promoting both evacuation during heavy rainfall and contact reduction behaviors as a measure against COVID-19 infection. Specifically, social influence nudges that use a gain frame to convey that a person's behavior promotes the behavior of others are effective for both heavy rainfall evacuations and encouraging COVID-19 vaccination.

Strong Precipitation and Human Activity Spur Rapid Nitrate Deposition in Estuarine Delta: Multi-Isotope and Auxiliary Data Evidence.

The intensive development of the Yellow River Delta has caused huge transportation of non-point pollutants into the Bohai Sea through source river estuaries and thus poses a considerable threat to eco-environmental security in the region. Long-term irrigation in the Yellow River basin, with occasional heavy rainfall and the related effects of ensuring hydrological processes and human activities in terms of nitrate N transport via surface water systems, is unclear. Using stable isotope (δ2H-H2O and δ18O-H2O, δ15N-NO3- and δ18O-NO3-) and auxiliary geographic data, the ISO source model was run to quantitatively analyze the supply relationship of river systems and the rapid change in the spatial pattern of nitrate N due to heavy rainfall in the estuarine delta. This analysis made clear the dominant contribution of agricultural activities and urbanization to NO3--N emission, on which basis refined management measures were proposed to deal with NO3- in surface water from the "source-process". The results of the study show that: (1) The relationship of surface water replenishment in the Yellow River Delta was affected not only by rainfall, irrigation, and other water conservancy measures but also the proportion of water from Yellow River flow declined from the source to estuary; (2) To a certain extent, rainfall diluted the concentration of nitrate N in the river and increased instantaneous flux of nitrate N into the sea, where nitrate N flux continuously increased from upstream to downstream; (3) The rapid deposition of nitrate in the estuary delta was driven by heavy rainfall and human activities such as excessive use of nitrogen fertilizers, rapid urbanization, and livestock waste discharge, and; (4) Scientific measures were needed to realize the interactive effect of the output of non-point source pollutants and the carrying and absorption capacity of coastal fragile ecosystems of the exogenous inputs.

Increased risk of Legionella pneumonia as community-acquired pneumonia after heavy rainfall in 2018 in west Japan.

INTRODUCTION: Japan experienced a heavy rainfall event from June 28 to July 8, 2018, and many casualties were caused by both heavy rainfall and flooding. Few studies have investigated patients' characteristics and the causative pathogens of community-acquired pneumonia before and after heavy rainfall events. The aim of the present study was to evaluate the causative pathogens and clinical characteristics of hospitalized patients with community-acquired pneumonia before and after the heavy rainfall event using prospective cohort data. METHODS: The study was divided into two periods: July to November 2013-2017 (before heavy rainfall) and July to November 2018 (after heavy rainfall). The patients' clinical characteristics and causative pathogens before and after the heavy rainfall were investigated. Regarding the causative pathogens, adjustments were made for precipitation and seasonal patterns. RESULTS: There were no significant differences in the number and clinical characteristics of patients before and after heavy rainfall. However, the frequency of Legionella pneumonia was significantly higher after than before the heavy rainfall event (8.9% vs 3.0%, P = 0.02) and remained significant after adjusting for precipitation and season. Three of 7 Legionella pneumonia patients engaged in reconstruction work and 2 Legionella pneumonia patients had soil exposure. CONCLUSIONS: An increased risk of Legionella pneumonia after not only rainfall and serious flooding, but also following recovery work or soil exposure should be considered.