Global expansion of tropical cyclone precipitation footprint.

Precipitation from tropical cyclones (TCs) can cause massive damage from inland floods and is becoming more intense under a warming climate. However, knowledge gaps still exist in changes of spatial patterns in heavy TC precipitation. Here we define a metric, DIST30, as the mean radial distance from centers of clustered heavy rainfall cells (> 30 mm/3 h) to TC center, representing the footprint of heavy TC precipitation. There is significant global increase in DIST30 at a rate of 0.34 km/year. Increases of DIST30 cover 59.87% of total TC impact areas, with growth especially strong in the Western North Pacific, Northern Atlantic, and Southern Pacific. The XGBoost machine learning model showed that monthly DIST30 variability is majorly controlled by TC maximum wind speed, location, sea surface temperature, vertical wind shear, and total water column vapor. TC poleward migration in the Northern Hemisphere contributes substantially to the DIST30 upward trend globally.

Characteristics of precipitation changes during tropical cyclone processes in China from 1980 to 2019.

Tropical cyclones (TCs) and their associated intense rainfall are among the most significant natural disasters. Exploring the characteristics of tropical cyclone precipitation (TCP) has always been a challenging issue in TC research. This study utilized the TC track data from the International Best Track Archive for Climate Stewardship and precipitation data from the multi-source weighted-ensemble precipitation covering the years 1980-2019, to examine shifts in precipitation rates and peak precipitation levels before and after TC landfall. The results highlight several key findings: (1) Precipitation during the TC landfall process is relatively stable beforehand but tends to decrease slightly after landfall. Generally, the maximum precipitation occurs during the landfall. (2) From 1980 to 2019, the rate of precipitation changes before landfall has significantly increased. Conversely, after the year 2000, the rate of precipitation changes after landfall has significantly decreased. (3) Over the past 40 years, while peak precipitation levels of landfalling TCs have remained relatively constant, the total precipitation has shown an increasing trend, particularly in regions like the main island of Hainan, southern Zhejiang, and Shanghai, which are characterized by high peak precipitation. The results help clarify the TC processes and provide reference points for parameter selection in regional TCP modeling.

Changes in the spatiotemporal patterns of dry/wet abrupt alternation frequency, duration, and severity in Mainland China, 1980-2019.

Changes in extreme events have received increasing attention in the context of climate change. Extreme changes in wet and dry events due to changes in meteorological elements, such as the spatial and temporal redistribution of precipitation and temperature increases, are extreme weather events that have attracted much attention in recent years. In contrast, there is a relative lack of research on extreme compound events that focuses on a transition between wet and dry spells in adjacent months. This paper provides maps of the frequency, duration, and severity of national-scale dry wet abrupt alternation (DWAA) events for 1980-1999 and 2000-2019, aiming to obtain information regarding events in the hotspot areas of DWAA in China during the past four decades in order to analyze their change patterns. This paper performs station-based standardized precipitation evapotranspiration index (SPEI) calculations to characterize local wet and dry spells based on meteorological observations provided by the China Meteorological Administration (CMA) since 1980 with regional analyses based on seven geographic divisions of China. Our finding explicitly discloses the "more-less-more" DWAA variation pattern from North to South China. Additionally, the changes in frequency, duration, and severity in the different regions are revealed. The frequency, duration, and severity of DW increased from 5.08 to 6.74, 17.71 to 24.62, and 12.51 to 17.01, respectively, an increase of 32.53%, 39.04% and 36.01%, while the corresponding WD only increased by 9.45%, 15.22% and 13.51%. In addition, events with a higher severity of DWAA are prone to appear in most regions due to the increasing interval between heavy rainfall and the increase in precipitation under global warming.

Exploring community evolutionary characteristics of microbial populations with supplementation of Camellia green tea extracts in microbial fuel cells.

This first-attempt study deciphered combined characteristics of species evolution and bioelectricity generation of microbial community in microbial fuel cells (MFCs) supplemented with Camellia green tea (GT) extracts for biomass energy extraction. Prior studies indicated that polyphenols-rich extracts as effective redox mediators (RMs) could exhibit significant electrochemical activities to enhance power generation in MFCs. However, the supplementation of Camellia GT extract obtained at room temperature with significant redox capabilities into MFCs unexpectedly exhibited obvious inhibitory effect towards power generation. This systematic study indicated that the presence of antimicrobial components (especially catechins) in GT extract might significantly alter the distribution of microbial community, in particular a decrease of microbial diversity and evenness. For practical applications to different microbial systems, pre-screening criteria of selecting biocompatible RMs should not only consider their promising redox capabilities (abiotic), but also possible inhibitory potency (biotic) to receptor microbes. Although Camellia tea extract was well-characterized as GRAS energy drink, some contents (e.g., catechins) may still express inhibition towards organisms and further assessment upon biotoxicity may be inevitably required for practice.

Typhoon track change-based emergency shelter location-allocation model: a case study of Wenchang in Hainan province, China.

BACKGROUND: Determining the locations of disaster emergency shelters and the allocation of impacted residents are key components in shelter planning and emergency management. Various models have been developed to solve this location-allocation problem, but gaps remain regarding the processes of hazards. This study attempts to develop a model based on the change of typhoon track that addresses the location-allocation problem for typhoon emergency shelters. PURPOSE: To consider the changes in candidate shelters and number of evacuees due to the change in impact area with the progression of a typhoon. METHODS: The proposed model is composed of several static processes and solved by a modified particle swarm optimisation algorithm with a restart strategy. RESULTS: The model is illustrated with the case of the evacuation process for Wenchang in Hainan province during Typhoon Rammasun in 2014 and Typhoon Mirinae in 2016. For the case of Typhoon Rammasun in 2014, the residents from east to west need to evacuate in three phases. For the case of Typhoon Mirinae in 2016, residents in the northern communities need not to evacuate to candidate shelters because they are not affected by the typhoon. CONCLUSION: The proposed model has advantages compared with non-typhoon track change-based model in saving time spent in shelters for residents and saving public resources for the local governments. With the proposed model, a manager could efficiently evacuate residents by considering the typhoon conditions.

A Hollow-Structured Manganese Oxide Cathode for Stable Zn-MnO2 Batteries.

Aqueous rechargeable zinc-manganese dioxide (Zn-MnO2) batteries are considered as one of the most promising energy storage devices for large scale-energy storage systems due to their low cost, high safety, and environmental friendliness. However, only a few cathode materials have been demonstrated to achieve stable cycling for aqueous rechargeable Zn-MnO2 batteries. Here, we report a new material consisting of hollow MnO2 nanospheres, which can be used for aqueous Zn-MnO2 batteries. The hollow MnO2 nanospheres can achieve high specific capacity up to ~405 mAh g−1 at 0.5 C. More importantly, the hollow structure of birnessite-type MnO2 enables long-term cycling stability for the aqueous Zn-MnO2 batteries. The excellent performance of the hollow MnO2 nanospheres should be due to their unique structural properties that enable the easy intercalation of zinc ions.

Increase of Elderly Population in the Rainstorm Hazard Areas of China.

In light of global warming, increased extreme precipitation events have enlarged the population exposed to floods to some extent. Extreme precipitation risk assessments are of great significance in China and allow for the response to climate change and mitigation of risks to the population. China is one of the countries most influenced by climate change and has unique national population conditions. The influence of extreme precipitation depends on the degree of exposure and vulnerability of the population. Accurate assessments of the population exposed to rising rainstorm trends are crucial to mapping extreme precipitation risks. Studying the population exposed to rainstorm hazard areas (RSHA) at the microscale is extremely urgent, due to the local characteristics of extreme precipitation events and regional diversity of the population. The spatial distribution of population density was mapped based on the national population census data from China in 1990, 2000 and 2010. RSHA were also identified using precipitation data from 1975-2015 in China, and the rainstorm tendency values were mapped using GIS in this paper. The spatial characteristics of the rainstorm tendencies were then analyzed. Finally, changes in the population in the RSHA are discussed. The results show that the extreme precipitation trends are increasing in southeastern China. From 1990 to 2010, the population in RSHA increased by 110 million, at a rate of 14.6%. The elderly in the region increased by 38 million at a rate of 86.4%. Studying the size of the population exposed to rainstorm hazards at the county scale can provide scientific evidence for developing disaster prevention and mitigation strategies from the bottom up.

Influence of textile dye and decolorized metabolites on microbial fuel cell-assisted bioremediation.

As known, decolorized metabolites (DMs) were capable to act as electron shuttles (ESs) to enhance color removal of textile dye(s); however, optimal manipulation of such advantages to microbial fuel cell (MFC)-assisted dye decolorization for industrial practicability were still remained open to be disclosed. The novelty of this work was to disclose such DMs-supplementing strategies for the most promising reductive decolorization in MFC-assisted bioremediation. Quantitative assessment clearly indicated that MFCs coupled to DMs accumulation was economically-feasible strategy of bioaugmentation and biostimulation. That is, MFC technology can be applied to select appropriate on-site dye decontamination in the presence of naturally-generating DMs.

Deciphering synergistic characteristics of microbial fuel cell-assisted dye decolorization.

This study provided a novel evaluation scheme to quantitatively reveal "synergistic" stimulation of microbial fuel cell (MFC)-assisted dye decolorization for industrial practicability. This work also disclosed why dye decolorization was more electrochemically favorable during simultaneous bioelectricity generation and dye decolorization (SBG&DD). Quantitative assessment upon stimulating effects of different decolorized metabolites on BG and DD alone was also implemented for conclusive remarks. Apparently, using MFC as the method of dye decontamination could considerably increase ca. 40-70% of electron transfer capabilities for SBG&DD, thereby significantly improving the performance of dye decontamination.

Exploring redox-mediating characteristics of textile dye-bearing microbial fuel cells: thionin and malachite green.

Prior studies indicated that biodecolorized intermediates of azo dyes could act as electron shuttles to stimulate wastewater decolorization and bioelectricity generation (WD&BG) in microbial fuel cells (MFCs). This study tended to explore whether non-azo textile dyes (i.e., thionin and malachite green) could also own such redox-mediating capabilities for WD&BG. Prior findings mentioned that OH and/or NH2 substitute-containing auxochrome compounds (e.g., 2-aminophenol and 1,2-dihydroxybenzene) could effectively mediate electron transport in MFCs for simultaneous WD&BG. This work clearly suggested that the presence of electron-mediating textile dyes (e.g., thionin and malachite green (MG)) in MFCs is promising to stimulate color removal and bioelectricity generation. That is, using MFCs as operation strategy for wastewater biodecolorization is economically promising in industrial applications due to autocatalytic acceleration of electron-flux for WD&BG in MFCs.

Deciphering characteristics of bicyclic aromatics--mediators for reductive decolorization and bioelectricity generation.

This first-attempt study quantitatively assessed electron-mediating characteristics of bicyclic aromatics - 1-amino-2-naphthol, 4-amino-1-naphthol (i.e., decolorized intermediates of azo dyes - orange I and II) for color removal and power generation in MFCs. According to cyclic-voltammetric profiles, the presence of reduction and oxidation peak potentials clearly suggested a crucial role of these intermediates as electron-shuttling mediators. Shake-flask cultures also showed that appropriate accumulation of 1A2N, 4A1N apparently enhanced color-removal efficiencies of bacterial decolorization. This study clearly suggested that suitable supplementation of electrochemically active electron shuttle(s) to dye-bearing MFCs is a promising strategy to stimulate reductive decolorization and bioelectricity generation.