Heavy Summer Rainfall Research Articles

Improved Simulation of Summer Heavy Rainfall over Beijing and Henan by the YHGSM with Updated Subgrid Orographic Parameters

Improved Simulation of Summer Heavy Rainfall over Beijing and Henan by the YHGSM with Updated Subgrid Orographic Parameters

Long-Term Energy Yield Analysis of the Rooftop PV System in Climate Conditions of Poland

In the past four years, the number of prosumers utilizing photovoltaic (PV) installations in Poland has increased significantly, exceeding 1.3 million, reaching a total power capacity of 10.5 GW by the end of 2023. This paper presents a three-year energy yield analysis of the prosumer PV systems operating in Eastern Poland. The 9.6 kW system consists of high-efficiency monocrystalline photovoltaic modules in half-cut technology. Over the three years of operation, specific yields have been analyzed along with weather parameters, such as solar intensity, outdoor temperature, humidity, wind speed, rainfall, or snowfall. The average annual final yield was found to be relatively high, exceeding 1000 kWh·kW−1 in each of the analysed years. The highest monthly specific yields of the analysed period were noticed during the summer, reaching the maximum value of 164 kWh·kW−1 in 2022. The daily final yields varied from a minimum of 0.15 kWh·kW−1 in Winter 2021 to a maximum of 6.8 kWh·kW−1 in Spring 2022. Weather conditions increasing the energy yields, such as low average ambient temperatures together with high insolation periods, were noticed. Energy production in such favorable conditions reached a surprisingly high value of energy yield in April 2020, comparable to the summer months (151.0 kWh·kW−1). The occurrence of heavy rainfall in summer was also noted as a desirable effect that leads to the natural cleaning of the PV modules. The average performance ratio during the analyzed period was found to be 0.85. The energy production of the PV system allowed the reduction of about 21 tons of CO2 emission.

The Quantitative Role of Moisture and Vertical Motion in Shaping Summer Heavy Rainfall over North China under Two Distinct Large-Scale Weather Patterns

Abstract Two distinct categories of weather patterns, denoted as Type 1 and Type 2, which show higher-than-expected frequency of summer heavy rainfall days (HRDs) over North China (NC), are selected from nine weather patterns categorized by the self-organizing map algorithm during 1979–2019. The respective HRDs over NC exhibit dissimilar characteristics, with Type 1 showing a northern distribution and Type 2 a southern distribution. The quantitative disparities in terms of moisture content and vertical motion are discussed in reactions to the synoptic-scale patterns associated with HRDs. The outcomes of a 20-day backward tracking, using the so-called Water Accounting Model-2layers, reveal noteworthy contrasts in moisture sources. Type 1 predominantly receives moisture from the western North Pacific, while Type 2 relies more on contributions from the Arabian Sea, Bay of Bengal, and Eurasia. However, the major moisture sources with grid cells contributing more than 0.01 mm show a consistent cumulative contribution of 77% for Type 1 and 80% for Type 2. The finding suggests that the discrepancy between the two types cannot be solely attributed to moisture supply. Further examination of the transverse and shearwise Q-vector components provides insights into how these distinct weather patterns influence HRDs by the alteration of vertical motion. In Type 1, an upper-level jet entrance induces a thermally direct secondary circulation that enhances vertical motion, while a baroclinic trough plays a dominant role in generating vertical motion in Type 2. Moreover, these unique configurations for each type of weather pattern are not only pre-existing but also intensified during HRDs.

Effect of rainfall in shaping microbial community during Microcystis bloom in Nakdong River, Korea

Various environmental factors play a role in the formation and collapse of Microcystis blooms. This study investigates the impact of heavy rainfall on cyanobacterial abundance, microbial community composition, and functional dynamics in the Nakdong River, South Korea, during typical and exceptionally rainy years. The results reveal distinct responses to rainfall variations, particularly in cyanobacterial dominance and physicochemical characteristics. In 2020, characterized by unprecedented rainfall from mid-July to August, Microcystis blooms were interrupted significantly, exhibiting lower cell densities and decreased water temperature, compared to normal bloom patterns in 2019. Moreover, microbial community composition varied, with increases in Gammaproteobacteria and notably in genera of Limnohabitans and Fluviicola. These alterations in environmental conditions and bacterial community were similar to those of the post-bloom period in late September 2019. It shows that heavy rainfall during summer leads to changes in environmental factors, consequently causing shifts in bacterial communities akin to those observed during the autumn-specific post-bloom period in typical years. These changes also accompany shifts in bacterial functions, primarily involved in the degradation of organic matter such as amino acids, fatty acids, and terpenoids, which are assumed to have been released due to the significant collapse of cyanobacteria. Our results demonstrate that heavy rainfall in early summer induces changes in the environmental factors and subsequently microbial communities and their functions, similar to those of the post-bloom period in autumn, leading to the earlier breakdown of Microcystis blooms.

Moisture Sources and Transport Paths during the Summer Heavy Rainfall Events in the Three-River-Headwater Region of the Tibetan Plateau

Moisture Sources and Transport Paths during the Summer Heavy Rainfall Events in the Three-River-Headwater Region of the Tibetan Plateau

AMO modulation of interdecadal background of persistent heavy rainfall in summer over the Huaihe River Basin

This study used observed rainfall, ERA5 reanalysis, and CMIP6 model datasets to investigate the interdecadal variation and underlying mechanism of persistent heavy rainfall (PHR) over the Huaihe River Basin (HRB) in China during July–August, and to examine the role of the Atlantic Multidecadal Oscillation (AMO) in modulating such rainfall. The results indicate that PHR over the HRB exhibited a marked interdecadal variation. The interdecadal increase in PHR was found attributable primarily to interdecadal enhancement of ascending motion, which might have been due to external forcing by the AMO. The AMO can trigger upper-tropospheric mid–high-latitude Rossby wave trains that can lead to an upper-tropospheric anticyclone and a lower-tropospheric cyclone configuration over the HRB. Increased warm advection and greater transport of water vapor from lower latitudes, caused by enhanced southerlies in the middle–lower troposphere over the HRB, can also lead to enhanced ascending motion over the HRB. Meanwhile, an anomalous cyclone over northeastern China triggered by AMO can transport cold air from higher latitudes to the HRB, boosting convection and promoting the development and duration of PHR. By affecting sea surface temperature in the western North Pacific Ocean, the AMO can also indirectly cause a meridional teleconnection pattern in the lower troposphere, which increases the transport of water vapor to the HRB. Numerical model experiments can reproduce both the interdecadal variations in PHR and the mechanisms of the influence of the AMO on PHR, providing a reliable foundation for understanding and forecasting PHR over the HRB.

Sources and transport of CO2 in the karst system of Jiguan Cave, Funiu Mountains, China

Conveyance and modification of carbon-isotope signals within the karst system remain difficult to constrain, due to the complexity of interactions between multiple components, including precipitation, bedrock, soil, atmosphere, and biota. Cave monitoring is thus critical to understanding both their transport in the karst system and dependence on local hydroclimatic conditions. Jiguan Cave, located in Funiu Mountain in central China, is representative of karst tourist caves with relatively thin epikarst zone. We conducted a comprehensive monitoring program of cave climate from 2018 to 2021 and measured δ13C during 2021 in monthly and heavy-rainfall samples of soil CO2, cave CO2, cave water (drip water and underground river), and underground river outlet. Our results demonstrate synchronous variations between CO2 concentration and δ13CCO2 in both soil and cave air on seasonal time scales. Cave pCO2 and carbon-isotope composition further exhibited a high sensitivity to human respiration with fluctuations of ~2000–3000 ppm within 4 days during the cave closure period in July 2021 without tourists. 13C-depleted isotopic signal of cave air in summer is the mixture of human respiration and soil CO2 which varies as a function of regional hydrological conditions of the summer monsoon during the rainy season with high temperatures and humidity. However, respired CO2 from the overlying soil was expected to be the only principal source of the cave CO2 when the anthropogenic CO2 source was removed. The high seasonal amplitude of cave air δ13CCO2 reflects ventilation dynamics, which leads to a prominent contribution from the external atmosphere during winter. Intriguingly, although the δ13C signal reflects complex vertical processes in the vertical karst profile, a heavy summer rainfall event was related to anomalously high δ13C values of cave water that can be utilized to interpret rainfall intensity and regional hydroclimate.

Spatiotemporal analysis of heavy summer rainfall events across the Free State Province, South Africa: 1981–2022

ABSTRACT Heavy rainfall events negatively impact agricultural productivity (e.g. crop damage) and human health (e.g. waterborne disease outbreaks). Under anthropogenically induced warming, South Africa may experience more frequent and heavier rainfall events during the summer wet-season. Evidence from point-based rainfall records suggests that such changes may already be occurring across many summer rainfall zone regions; however, the understanding thereof is spatially unresolved. Therefore, focusing on the summer rainfall zone Free State Province, we used the CHIRPS rainfall dataset for 1981/82–2021/22 to explore trends and interannual variability in the magnitude and frequency of heavy rainfall events for summer months (October–April). Interannually, the El Niño-Southern Oscillation had a predictable influence, with positive (negative) anomalies for the frequencies and magnitudes of heavy rainfall events during La Niña (El Niño) years. Despite few statistically significant trends, the results broadly depict increases (decreases) by up to 0.4 days/decade (−0.2 days/decade) in the frequency of smaller (larger) heavy rainfall events. More consistent trend results were evident for heavy rainfall event magnitude indices, with declining (increasing) trends, up to −2 mm/decade (5 mm/decade), evident over central (northeastern and southwestern) regions. Our results highlight regions vulnerable to changes and interannual variations in heavy rainfall characteristics, which can inform adaptation strategies.

Estimation of Coastal Area and Lake Water Level Changes Using High-Resolution Altimetry

Radar satellite altimeters are widely used in offshore areas, whereas they are underutilized in coastal areas due to a number of interference factors. Altimeter satellite data can be used to summarize elevation information at 1 Hz for offshore areas, but for areas close to land, it is more effective to utilize imagery with a resolution of 20 Hz to provide a more detailed representation. The use of highresolution satellite altimeter data is expected to increase the amount of data available for hydrological data such as complex coastlines and small lakes. Therefore, in this study, we investigated the applicability of 20 Hz altimeter data in the Korean Peninsula. First, the accuracy was analyzed by comparing the 20 Hz altimeter data from the Jason-3 satellite with the Ulleungdo tide data. Second, we compared the 20 Hz altimeter data from the Sentinel-3A satellite with the water level data of Soyang Lake to see if it can be applied to land areas. In the case of inland lakes, the water level is estimated to be affected by the discharge volume due to heavy rainfall in summer, and it was determined that the satellite altimeter data can be utilized. Therefore, utilizing the data from this study is expected to improve the accuracy of hydrological analysis in coastal and lake environments.

Residual circulations and wind conditions affect the transport and distribution of Pb

Hydrodynamic conditions affect the dispersion and transportation of pollutants. In this study, 102 surface water samples were collected and numerical simulations were conducted by coupling SWAT (Soil and Water Assessment Tool) and MIKE 21 models to investigate the effect of hydrodynamic conditions on the transport and distribution of Pb in Jiaozhou Bay, China. The tidal current velocity was lowest at flood tide and highest at ebb tide in summer, mainly due to the strong runoff caused by heavy rainfall in summer. The velocity of the residual current near the bay mouth was high, with an average value of 0.32 m/s. The residual currents had alternating clockwise and counter-clockwise circulations of different diameters in the bay mouth and the northern bay. The circulation diameter in the bay mouth area was large, and the circulation extended from the bay mouth to the Yellow Sea. Due to the small circulation diameters and opposite directions of the adjacent circulations in the northern bay, pollutants were easily trapped there. The dissolved Pb particles released from the northern bay mainly migrated to the shore, while the dissolved Pb particles released from the bay mouth tended to migrate to the Yellow Sea. The dominant wind directions and residual currents were the main driving forces affecting the trajectories of the particle tracking simulations. The dissolved Pb concentration in the water was high near shore and in the southwestern bay and under the combined effects of tidal residual current, wind force, and river and wastewater inputs. The low Pb concentration near the bay mouth was mainly influenced by the high residual current velocity. These results can provide improved insights into the mechanism of Pb transport and distribution in a semi-enclosed bay.

Forecast of the development of thermal erosion processes in the Yamalo-Nenets Autonomous Okrug under modern climate changes

The study of exogenous processes and their effects on natural and anthropogenic systems is a very important aspect for the development of Arctic territories. One of these processes is thermal erosion, which is widespread in the Yamalo-Nenets Autonomous District due to the presence of permafrost in the vast majority of its area. The main prerequisites for the manifestation of thermal erosion processes can be divided into several groups of factors. Firstly, the geomorphological characteristics of the territory play a key role: the lengths and slopes. Secondly, the lithological and granulometric composition of rocks, as well as ice content and temperature, determine the resistance of the soil to the thermal and mechanical effects of flowing water. Thirdly, the amount of precipitation is an important factor, especially precipitation in winter and heavy rainfall in summer. They contribute to a high concentration of runoff in short periods of time, which leads to rapid destruction of rocks and the removal of large volumes of loose material. Finally, the fixation of the top layer of soils by the root system can be considered the main reason that counteracts the development of thermal erosion. The purpose of this study is a prognostic assessment of the risks of the development of thermal erosion processes in the context of the observed climate warming. To assess the risks, data from climate modeling of the Yamalo-Nenets Autonomous District for the middle of the XXI century were used for an ensemble of climate models included in the CMIP6 project. The analysis of Google Earth satellite images and information about the geological and geomorphological features of the region are used for zoning the territory in terms of dynamics and dangers of thermal erosion. The result of the study was the compilation of a map of the Yamalo-Nenets Autonomous District by categories of risks associated with thermal erosion processes. It is shown that in the perspective of several decades, more than 50% of the region's area is subject to intensification of thermal erosion destruction of soils, which requires careful planning of economic development and design of protective structures. An attempt has been made to assess the impact of erosive and thermoerosive effects on the natural environment of the Yamalo-Nenets Autonomous Okrug due to climate change using the recommendations of this assessment by Order of the Ministry of Economic Development of the Russian Federation dated 05/13/2021 N 267. Climatic factors can seriously enhance the causes and negative consequences of the development of thermoerosion, while local manifestations should be assessed using field data based on the calculation methods.

The Merits of Ocean Prediction for the Prediction of 2010, 2016, and 2021 Summer Heavy Rainfall Events in Japan

The merits of ocean prediction for heavy rainfall prediction were examined using hindcast experiments for three summer heavy rainfall events in 2010, 2016, and 2021 in Japan. In these events, the rainfall stemmed from Baiu and stationary fronts. The hindcast experiments were conducted using regional atmospheric and coupled models (RUN-ATM and RUN-CPL). The results show that RUN-CPL predicted more accurate rainfall properties than RUN-ATM. RUN-ATM underestimated the accumulated rainfall compared with RUN-CPL, and the underestimation became more significant as the lead time increased. This was due to decreased horizontal vapor transport in the ocean southwest of Japan. Pressure patterns that dominated the vapor transport were different in each case. When an atmospheric model was used, the sea level pressure difference between the Pacific high and Japan was weakened, contributing to weaker vapor transport from the southwest because of the weakened anticyclonic and cyclonic circulations at the region of Pacific high and over Japan. The degraded pressure patterns generated by RUN-ATM stemmed from incorrect latent heat flux response to the sea surface temperature. When air-sea was decoupled in the atmospheric model, the decrease of sea surface temperature by latent heat flux did not occur, so the latent heat flux was overestimated. Also, this caused the decrease in the pressure difference between Pacific high and Japan areas, leading to a weaker moisture transport from the ocean southwest of Japan. The heat budget analysis in the ocean mixed layer suggests that ocean dynamics, especially vertical mixing, contributes to suppress the overestimation of latent heat flux around the Pacific high. It is concluded that heavy rainfall prediction that incorporates appropriate air-sea coupling and ocean prediction provides better results than atmosphere-only model prediction for front-derived heavy rainfall events.

Numerical Simulation Reflecting Buildings in Area Damaged by Debris flow

More than 80% of average annual precipitation in South Korea occurs between June and September owing to heavy rainfall and typhoons in summer, and its land is vulnerable to mountain disasters (landslides and debris flow) as 63% of it is mountainous areas. In this study, an area damaged by debris flow in Wondeok-eup, Samcheok-si, Gangwon-do, Korea under the influence of Typhoon Mitag in 2019 was surveyed and numerical modeling was performed. Topographic data were created using the 5m grid DEM derived through the field survey data and GIS technique as well as the building data of the damaged area, and debris flow modeling was performed using the Hyper KANAKO model. A comparison with the inundation trace map showed that the simulation results based on topographic data that reflected buildings exhibited similar flow patterns and characteristics to the actual damage.

Effect of sponge city construction on urban waterlogging reduction in semi-humid areas of China

Abstract Urban waterlogging frequently occurs in semi-humid areas due to the short duration of heavy rainfall in summer and the high rates of subsurface hardening caused by high-intensity urban development. To solve the problem of urban waterlogging, China has launched the construction of ‘sponge cities’ and made some progress, but there is still a lack of comprehensive consideration of the functional types and spatial layout of low impact development (LID) facilities. Qian'an, a city of Hebei Province, is one of the first sponge city pilot cities in China. This paper focuses on Yanshan South Road and its surrounding areas, a historical waterlogging section of Qian'an city. Four common LID measures (sunken green space (SG), bioretention ponds (BP), infiltration ponds (IP), and reservoirs (RE)) in two function types are selected and combined through centralized (CE) and decentralized (DE) different spatial layouts, a total of 80 design scenarios are proposed. Then, using the storm water management model (SWMM) to calculate the effect of each scheme on peak flow reduction under different rainfall return periods. The results showed that all LID scenarios can effectively alleviate the urban waterlogging problem, among which the schemes of DE-SG-BP (1:1), DE-IP-SG (1:1), DE-SG-IP (3:1), DE-SG-IP (1:3), and DE-SG-BP (3:1) had the highest peak flow reduction rate, up to 95.46%. The schemes of CE-RE-IP (3:1) and CE-IP-RE (3:1) had better hydrological performance in occupying less surface space, with a peak flow reduction rate of 8.68% per square meter. Therefore, the distributed layout combined with infiltration LID facilities and storage LID facilities can be used in urban built-up areas with limited land use conditions, which has a more obvious effect on reducing waterlogging.

Multiscale Processes of Heavy Rainfall over East Asia in Summer 2020: Diurnal Cycle in Response to Synoptic Disturbances

Abstract Multiscale processes from synoptic disturbances to diurnal cycles during the record-breaking heavy rainfall in summer 2020 were examined in this study. The heavy rainfall consisted of eight episodes, each lasting about 5 days, and were associated with two types of synoptic disturbances. The Type-1 episodes featured a northwestward extending western Pacific subtropical high (WPSH), while the Type-2 episodes had approaching midlatitude troughs with southward retreat in the WPSH. Each heavy rainfall episode had 2–3 occurrences of nocturnal low-level jets (NLLJs), in close association with intense rainfall in the early morning. The NLLJs formed partly due to the geostrophic wind by increased pressure gradients under both types of synoptic disturbances. The NLLJs were also driven by the ageostrophic wind that veered to maximum southerlies at late night due to the boundary-layer inertial oscillation. The diurnal amplitudes of low-level southerlies increased remarkably after the onset of Type-1 episodes, in which the extending WPSH provided strong daytime heating from solar radiation. By contrast, the wind diurnal amplitudes were less changed after the onset of Type-2 episodes. The NLLJs strengthened the mesoscale mean ascent, net moisture flux convergence, and convective instability in elevated warm moist air, which led to the upscale growth of MCSs at the northern terminus of the LLJ after midnight. The MCSs-induced Meiyu rainband was re-established in Central China during the Type-1 episodes with the increased diurnal variations. The findings highlight that the regional diurnal cycles of low-level winds in response to synoptic disturbances can strongly regulate mesoscale convective activities in a downscaling manner, and thus produce heavy rainfall.

Quantitative Attribution of Vertical Motion Responsible for Summer Heavy Rainfall Over North China

AbstractThis study explores synoptic‐scale circulation conditions that favor vertical motion on heavy rainfall days (HRDs) over North China (NC) and analyzes the quantitative contribution to vertical motion by different forcings using the quasi‐geostrophic (QG) omega equation. On HRDs, moisture is brought from the South China Sea and East China seas by surface cyclonic vortex activity. When South Asian High is located anomalously northward, NC is on the south side of the upper‐level jet (ULJ) stream entrance region. Diagnosis of the QG omega equation shows that vertical motion on HRDs is caused by dynamic forcing, diabatic forcing, and topographic forcing. The greatest contribution to vertical motion is from diabatic forcing, while topographic contributes to vertical motion at low levels. The dynamic forcing, which is manifested by the Q‐vector, indicates that both the ULJ and baroclinic trough generate the vertical motion. Furthermore, the effect of the baroclinic trough is larger than that of the ULJ. On medium rainfall days, the contributions from dynamic forcing, diabatic forcing, and topographic forcing are clearly weaker than on HRDs, with reductions of 62.3%, 71.3%, and 73.8%, respectively.

Retraction Note: Spatiotemporal variation of rainfall based on random sample classification and English vocabulary translation of imported products

In this paper, we use Monte Carlo simulation method to estimate the intra group correlation coefficient of the whole group of random sample classification design and recalculate the sample size according to the intra group correlation coefficient. Using this method, we can easily calculate the correlation coefficient and sample size and use the ODS function of SAS software to get word output. Then random samples are classified. In addition, this paper analyzes the relationship between summer heavy precipitation and spatial-temporal variation of circulation rainfall by using daily precipitation data of meteorological stations, NCEP reanalysis data, and relevant circulation index. Singular value decomposition (SVD) method is used to analyze the spatial correlation between spatial-temporal variation of summer rainfall and 500 hPa geopotential height; with the help of wavelet coherence and cross wavelet transform, the relationship between summer heavy rainfall and Western Pacific subtropical high and the relationship between East Asian summer monsoon and South China Sea summer monsoon are analyzed. Finally, the temporal and spatial variation of heavy rainfall in summer in this area is analyzed. With the development of economic globalization, the distribution of various products among countries becomes more and more frequent. In recent years, the number of imported products from China has increased, and many foreign products have entered the Chinese market. Because only in this way can people of different classes and ages know the basic characteristics and usage of the product. Standardizing English vocabulary translation of imported product description plays an important role in improving user’s product experience and increasing product sales. This paper adopts the method of random sample classification to study the temporal and spatial changes of rainfall and English vocabulary translation, so as to promote the development of imported products.

Analysis of Net Erosion Using a Physics-Based Erosion Model for the Doam Dam Basin in Korea

In Korea, approximately 70% of the country is mountainous, with steep slopes and heavy rainfall in summer from June to September. Korea is classified as a high-risk country for soil erosion, and the rate of soil erosion is rapidly increasing. In particular, the operation of Doam dam was suspended in 2001 because of water quality issues due to severe soil erosion from the upstream areas. In spite of serious dam sediment problems in this basin, in-depth studies on the origin of sedimentation using physic-based models have not been conducted. This study aims to analyze the spatial distribution of net erosion during typhoon events using a spatially distributed physics-based erosion model and to improve the model based on a field survey. The spatially uniform erodibility constants of the surface flow detachment equation in the original erosion model were replaced by land use erodibility constants based on benchmarking experimental values to reflect the effect of land use on net erosion. The results of the upgraded model considering spatial erodibility show a significant increase in soil erosion in crop fields and bare land, unlike the simulation results before model improvement. The total erosion and deposition for Typhoon Maemi in 2003 were 36,689.0 and 9893.3 m3, respectively, while the total erosion and deposition for Typhoon Rusa in 2002 were 142,476.6 and 44,806.8 m3, respectively, despite about twice as much rainfall and 1.2 times as high rainfall intensity. However, there is a limitation in quantifying the sources of erosion in the study watershed, since direct comparison of the simulated net erosion with observed spatial information from aerial images, etc., is impossible due to nonperiodic image photographing. Therefore, continuous monitoring of not only sediment yield but also periodic spatial detection on erosion and deposition is critical for reducing data uncertainty and improving simulation accuracy.

Pollution status, influencing factors and environmental risks of neonicotinoids, fipronil and its metabolites in a typical semi-closed bay in China

The occurrence, spatiotemporal variations, influence factors and environmental risks of eight common neonicotinoids (NEOs), fipronil, and three fipronil metabolites (fipronil and its metabolites are collectively referred to as FIPs) in different seasons from the estuary to the inner area of Jiaozhou Bay, China were comprehensively investigated. First- and second-generation NEOs were found to be the predominant pesticides in this area. The average contents of ∑NEOs and ∑FIPs from the estuary to the inner bay decreased from 12.99 ng/L to 0.82 ng/L and from 1.10 ng/L to 0.17 ng/L, respectively. NEO and FIP concentrations were higher in summer and autumn. High ∑NEO content is distributed in main inflow rivers, such as Dagu River and Licun River, which are influenced by pesticide application. NEO concentrations in all rivers were high upstream and low downstream because of the influence of heavy rainfall and seawater dilution in summer. NEO concentrations were high along the coast and low at the mouth and center of Jiaozhou Bay in summer and autumn and evenly distributed in winter and spring. Temperature has a great influence on most NEOs and FIPs owing to its effect on their degradation. Nitrogen-containing nutrients have an important influence on the distribution of fipronil and acetamiprid, which may be due to the activity of nitrogen-containing functional groups in their structure. Only Licun River, Dagu River and Haibo river sewage treatment plant in summer posed a certain risk of chronic toxicity for NEOs using the new threshold established by the species sensitive distribution (SSD) method for Chinese native aquatic lives. These findings should arouse people's attention.

A 40‐year climatology of summer heavy hourly rainfall over mountainous Shanxi in China

AbstractIn this study, a statistical analysis of the spatiotemporal characteristics of summer heavy hourly rainfall (HHR) events during 1979–2018 over mountainous Shanxi Province is performed in order to examine regional climate change over such a transition region between North China and Northwest China. Results show that the regional 40‐year annual mean summer rainfall is about 272 mm, about 37% of which is associated with HHR events. High‐frequency and high‐intensity HHR events tend to take place in eastern mountainous subregions, whereas most basin subregions experience HHR events with low frequency and low intensity, showing the important influences of local topography and its interaction with prevailing large‐scale flows. The important topographical influences are also reflected by the observations that most mountainous subregions exhibit a major late‐afternoon peak with a secondary early morning maximum, and that the associated diurnal variations are much greater in amplitude than those in basin subregions. It is found that the regional total annual summer rainfall has a decreasing trend during the first 20 years, mostly by non‐HHR contributions, but a rapid increasing trend during the recent 20 years, with dominant HHR contributions. Most subregions with the increasing trends of HHR frequency are those dominated by rapidly increasing surface temperatures. In particular, more frequent HHR events occur over major urbanization areas, that are in close proximity to complex topography, during the recent two decades. The decadal trends in HHR are found to be correlated to the distribution and intensity changes of the East Asian summer monsoon. The above results have important implications to the operational prediction of HHR events, and a better understanding of regional climate change over mountainous Shanxi Province.