Frequency Of Extreme Precipitation Research Articles

Projected Changes in Mean and Extreme Precipitation over Northern Mexico

Abstract Northern Mexico is home to more than 32 million people and is of significant agricultural and economic importance for the country. The region includes three distinct hydroclimatic regions, all of which regularly experience severe dryness and flooding and are highly susceptible to future changes in precipitation. To date, little work has been done to characterize future trends in either mean or extreme precipitation over northern Mexico. To fill this gap, we investigate projected precipitation trends over the region in the NA-CORDEX ensemble of dynamically downscaled simulations. We first verify that these simulations accurately reproduce observed precipitation over northern Mexico, as derived from the Multi-Source Weighted-Ensemble Precipitation (MSWEP) product, demonstrating that the NA-CORDEX ensemble is appropriate for studying precipitation trends over the region. By the end of the century, simulations forced with a high-emissions scenario project that both mean and extreme precipitation will decrease to the west and increase to the east of the Sierra Madre highlands, decreasing the zonal gradient in precipitation. We also find that the North American monsoon, which is responsible for a substantial fraction of the precipitation over the region, is likely to start later and last approximately three weeks longer. The frequency of extreme precipitation events is expected to double throughout the region, exacerbating the flood risk for vulnerable communities in northern Mexico. Collectively, these results suggest that the extreme precipitation-related dangers that the region faces, such as flooding, will increase significantly by the end of the century, with implications for the agricultural sector, economy, and infrastructure. Significance Statement Northern Mexico regularly experiences severe flooding and its important agricultural sector can be heavily impacted by variations in precipitation. Using high-resolution climate model simulations that have been tested against observations, we find that these hydroclimate extremes are likely to be exacerbated in a warming climate; the dry (wet) season is projected to receive significantly less (more) precipitation (approximately ±10% by the end of the century). Simulations suggest that some of the changes in precipitation over the region can be related to the North American monsoon, with the monsoon starting later in the year and lasting several weeks longer. Our results also suggest that the frequency of extreme precipitation will increase, although this increase is smaller than that projected for other regions, with the strongest storms becoming 20% more frequent per degree of warming. These results suggest that this region may experience significant changes to its hydroclimate through the end of the century that will require significant resilience planning.

Climate risk assessment and adaption ability in China's coastal urban agglomerations - A case study of Guangdong-Hong Kong-Macao greater bay area

As climate change intensifies, extreme weather events, especially the coastal flooding is becoming increasingly severe. Carbon emissions exacerbate climate change, leading to increased frequency and intensity of extreme precipitation, which may result in flooding. This study focuses on the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), a coastal city cluster in China, and adopts the scenario analysis approach to evaluate flood risks in the different carbon mitigation scenario from the perspectives of dangerousness, and adaption ability. The result shows that the Huizhou in the east of the GBA and the Zhaoqing in the northwest have the highest level of flood disaster risk. However, the central region of the GBA (Guangzhou, Dongguan, Zhongshan, and Foshan) is very vulnerable to disaster-inducing environments and hazard-affected bodies, which means that the flooding risk and the impact of such risk in the GBA display regional differentiation characteristics and the spatial patterns of them are different. According to the carbon neutrality scenario, the flood risk in the GBA peaks in 2030, and decreases during 2030–2090. In contrast, under the uneven development and high carbon pathways, the risk peaks in 2060, and the overall risk by 2090 is roughly the same as that in 2060. In addition, the regions with the highest flood disaster risk are Guangzhou, Foshan, Dongguan and Zhongshan along the Pearl River estuary. Overall, it shows that areas with higher levels of urbanization and more developed economies will face higher flooding risks. The “dangerousness-adaption ability” structure can reflect the spatial distribution pattern of flood disaster risks, identify the priority areas for flood prevention and control, and is conducive to risk management. At the same time, the research results show that ecological protection have a positive effect on reducing flood risk. In addition, corresponding policy recommendations for pre-disaster, mid-disaster and post-disaster have been proposed, providing references for flood risk management in the GBA.

Convection‐Permitting Climate Models Can Support Observations to Generate Rainfall Return Levels

AbstractInformation about the frequency and intensity of extreme precipitation is generally derived from fitting extreme value models using point‐observations, but the regionalization of these models is challenging. Here we propose using high‐resolution convection‐permitting climate model output as covariates for the estimation of observation‐based spatial rainfall return levels. We apply the Weather and Forecasting Research (WRF) model at a 1.5 km resolution driven by ERA5 reanalysis data over southern Germany, where 1,132 rain gauges provide observations of daily rainfall. For this complex topography, we build three different smooth spatial Generalized Extreme Value (GEV) models: (a) a reference model using latitude, longitude and elevation as covariates; (b) a model adding mean annual precipitation from the WRF; (c) a model adding extreme value statistical model estimates using WRF output. We show that the additional information provided by the WRF model can improve the representation of 10‐year and 100‐year return levels of daily rainfall by lowering the percentage bias, mean absolute error, and root‐mean‐square error. Furthermore, we conduct an extensive cross‐validation, where only 5%, 10%, 20%, 50%, 80%, 90%, and 95% of all rain gauges are considered when building spatial GEV models. Again, the additional information provided by the WRF model can improve results here. This cross‐validation study also highlights the robustness of our approach, showing great potential for use in data‐scarce regions.

Climatic characteristics of hourly extreme precipitation during the warm season in Chongqing

The study analyzed hourly extreme precipitation events in Chongqing and its six sub-regions from 2011 to 2021 during the warm season. Results showed uneven distribution of the 99.7th percentile hourly extreme precipitation threshold, with lower thresholds along the Yangtze River valley and higher thresholds in the Daba Mountains and Wuling Mountains. Both hourly extreme precipitation amount (HEPA) and intensity (HEPI) exhibited higher values in surrounding areas and lower values in the center, with the western, northeast, and southeastern regions experiencing the highest values. Spatial distribution of hourly extreme precipitation frequency varied, with higher frequencies in the northwestern and southern parts of Chongqing. Interannually, hourly extreme precipitation amount slightly increased, while intensity fluctuated. Monthly peak values for amount, frequency, and intensity occurred in July or August, and on a daily scale, the periods from 03:00 to 07:00 and 17:00 to 21: 00 exhibited higher values for amount and frequency, while the period from 11 :00 to 16:00 showed lower values. In summary, the study provided insights into the spatial and temporal patterns of hourly extreme precipitation events in Chongqing and its sub-regions during the warm season, highlighting variations in thresholds, distribution, and trends over the studied period.

Regulatory effects of non-growing season precipitation on the community structure, biomass allocation, and water-carbon utilization in a temperate desert steppe

Under the influence of global change, precipitation amounts and extreme precipitation frequency during non-growing seasons in mid-high latitude grasslands have been increasing. However, the ecological effects of non-growing season precipitation in the desert steppe have long been overlooked due to an insufficient understanding of the correlative mechanisms linking non-growing season precipitation to plant growth. Therefore, a 3-year non-growing season precipitation manipulation experiment was conducted to reveal the response of desert steppe plants to non-growing season precipitation changes. Our study indicates that, by influencing water budget and availability, non-growing season precipitation directly or indirectly impacted community structure, plant biomass allocation, and water-carbon utilization intensity. Adaptive strategies of communities and plants included: ① Dominant species enhanced their dominance in the community to adapt to non-growing season precipitation changes. ② Stipa krylovii exhibited different biomass allocation strategies in response to non-growing season precipitation variations. Plants in the precipitation shading plots tended to allocate biomass to the roots, while those in the precipitation increase plots favored aboveground development. ③ Persistent drought during the growing season intensified early insufficient development of plants in the precipitation shading plots. Upon entering the wet period, plants in the precipitation shading plots shifted into a compensatory growth mode with high water-carbon activity intensity, while those in the precipitation increase plots entered a moderate growth mode with relatively low water-carbon activity intensity. Additionally, our study found that the regulatory effects of non-growing season precipitation were more pronounced in the growing seasons with less precipitation in the early to middle stage. Moreover, increased non-growing season precipitation enhanced plant water use efficiency (WUE) and strengthened their resilience to drought conditions. Our study suggests that the ecological role of non-growing season precipitation may be further highlighted in the future climate change pattern. Given the worldwide increase in frequency of extreme precipitation events, particular vigilance should be paid to the underlying long-term adverse effects of severe droughts during the non-growing season. Our findings provide new insights and valuable experimental observational evidence for the climate change impact assessment and response in xerophytic grassland ecosystems.

Genetic diversity and candidate genes for transient waterlogging tolerance in mungbean at the germination and seedling stages.

Mungbean [Vigna radiata var. radiata (L.) Wilczek] production in Asia is detrimentally affected by transient soil waterlogging caused by unseasonal and increasingly frequent extreme precipitation events. While mungbean exhibits sensitivity to waterlogging, there has been insufficient exploration of germplasm for waterlogging tolerance, as well as limited investigation into the genetic basis for tolerance to identify valuable loci. This research investigated the diversity of transient waterlogging tolerance in a mini-core germplasm collection of mungbean and identified candidate genes for adaptive traits of interest using genome-wide association studies (GWAS) at two critical stages of growth: germination and seedling stage (i.e., once the first trifoliate leaf had fully-expanded). In a temperature-controlled glasshouse, 292 genotypes were screened for tolerance after (i) 4 days of waterlogging followed by 7 days of recovery at the germination stage and (ii) 8 days of waterlogging followed by 7 days of recovery at the seedling stage. Tolerance was measured against drained controls. GWAS was conducted using 3,522 high-quality DArTseq-derived SNPs, revealing five significant associations with five phenotypic traits indicating improved tolerance. Waterlogging tolerance was positively correlated with the formation of adventitious roots and higher dry masses. FGGY carbohydrate kinase domain-containing protein was identified as a candidate gene for adventitious rooting and mRNA-uncharacterized LOC111241851, Caffeoyl-CoA O-methyltransferase At4g26220 and MORC family CW-type zinc finger protein 3 and zinc finger protein 2B genes for shoot, root, and total dry matter production. Moderate to high broad-sense heritability was exhibited for all phenotypic traits, including seed emergence (81%), adventitious rooting (56%), shoot dry mass (81%), root dry mass (79%) and SPAD chlorophyll content (70%). The heritability estimates, marker-trait associations, and identification of sources of waterlogging tolerant germplasm from this study demonstrate high potential for marker-assisted selection of tolerance traits to accelerate breeding of climate-resilient mungbean varieties.

Global evidence of rapid flash drought recovery by extreme precipitation

Flash drought affects agricultural activities and water availability. However, the rate of flash drought development and termination and their controlling mechanisms remain mostly unexplored. Using climate reanalysis (ERA5) datasets, we examine the flash drought development and recovery rates in seventeen climate regions across the globe during the 1981–2020 period. In most global climate regions, flash drought recovery (25.2 percentile/pentad) is faster than its development rate (17.2 percentile/pentad). The tropical and sub-tropical humid areas, particularly eastern North America, northern South America, South Asia, Southeast Asia, and the Islands groups, are the hotspots of rapid flash drought development and faster recovery rates. In most climate regions, flash drought development and recovery rates have considerably increased during the recent two decades. Pluvial events (heavy-to-extreme precipitation) associated with increased soil moisture and decreased atmospheric aridity vapor pressure deficit are the primary driver of the rapid flash drought recovery. Globally, 10 of 17 regions showed the dominance of extreme precipitation in flash drought recovery, primarily due to an increase in the frequency of extreme precipitation. A fraction of flash droughts terminated by extreme precipitation has increased significantly across the most regions during 1981–2020. Considering the increase in flash drought frequency, development rate, and rapid termination, the compound risk of flash droughts followed by extreme precipitation and flooding has enhanced. The abrupt transition from flash drought to wet conditions makes drought and flood management more challenging, with consequences for agriculture and water resources.

Extreme precipitation trends in Northeast China based on a non-stationary generalized extreme value model

AbstractNortheast China is the main food production base of China. Extreme precipitation (EP) events can seriously impact agricultural production and socioeconomics, but the understanding of EP in Northeast China is still limited. In this study, using the non-stationary generalized extreme value (GEV) model, we investigate the trend and potential risk of EP in Northeast China during 1959–2017, especially in early and mid-summer (periods of high frequency of EP). Then, the relationships between EP and large-scale circulation over Northeast China in early and mid-summer are analyzed separately. The EP in Northeast China mainly presents positive trends in early summer but negative trends in mid-summer. Meanwhile, the EP with all the return periods presents apparently increasing trends in early summer, corresponding to more frequent EP events. Nevertheless, in mid-summer, the EP with 2-year return period decreases with location parameter, and the EP with 20-year, 50-year, and 100-year return periods slightly increases with scale parameter. The EP with 2-year return period occurs frequently in Liaoning Province, while the EP with 100-year return period is more likely to occur in Jilin Province and Heilongjiang Province. Moreover, the increase of the EP in early summer is mainly influenced by the northeast cold vortex; the effect of cold air on the EP is stronger in mid-summer, giving a clear explanation why the EP in mid-summer does not increase significantly. Overall, the outcomes of this study would be beneficial for the disaster prevention and mitigation in Northeast China.

Formation mechanisms of persistent extreme precipitation events over the eastern periphery of the Tibetan Plateau: Synoptic conditions, moisture transport and the effect of steep terrain

The eastern periphery of the Tibetan Plateau (EPTP) is prone to frequent and severe Persistent Extreme precipitation (PEP) events in summer. Given the complexity of weather systems and the intricate nature of terrain over this region, the generation and development mechanisms of the PEP in the EPTP remain to be determined. In this study, the formation and persistence mechanisms are further explored from the perspective of the general features of large-scale circulations, moisture source diagnosis and the influence of steep topography by using a thermal-dynamical diagnosis method, a mesoscale numerical simulation and a Lagrangian identification of the main moisture sources. The results show that during PEP events, the corresponding atmospheric circulation systems are characterized by an anomalous Rossby wave train at middle levels, an intensified westerly jet, an eastward extension of the South Asian high and a westward extension of the western Pacific subtropical high, all of which are possible to facilitate the development of potential instability and anticyclonic convergence of water vapor transport. The evaporative moisture sources from the Southeastern Asia (SEA), Bay of Bengal (BOB), and Southern China Sea (SCS) are remarkably enhanced during PEP events, with a contribution of 56.44%, which is 28.5% higher than the climatic mean. The further sensitive experiment indicates that the steep terrain could enhance the continuous transport of positive potential vorticity and the downward propagation of upper-level isentropic potential vorticity disturbances, thereby playing an essential role in the triggering and development of PEP events.

The impact of electrical hazards from overhead power lines on urban search and rescue operations during extreme flood events

Accurate flood forecasting and efficient emergency response operations are vital, especially in the case of urban flash floods. The dense distribution of power lines in urban areas significantly impacts search and rescue operations during extreme flood events. However, no existing emergency response frameworks have incorporated the impacts of overhead power lines on lifeboat rescue operations. This study aims to determine the necessity and feasibility of incorporating overhead power line information into an emergency response framework using Manville, New Jersey during Hurricane Ida as a test bed. We propose an integrated framework, which includes a building-scale flood model, urban point cloud data, a human vulnerability model, and network analysis, to simulate rescue operation feasibility during Hurricane Ida. Results reveal that during the most severe point of the flood event, 46% of impacted buildings became nonrescuable due to complete isolation from the road network, and a significant 67.7% of the municipality’s areas that became dangerous for pedestrians also became inaccessible to rescue boats due to overhead power line obstruction. Additionally, we identify a continuous 10-hour period during which an average of 43.4% of the 991 impacted buildings faced complete isolation. For these structures, early evacuation emerges as the sole means to prevent isolation. This research highlights the pressing need to consider overhead power lines in emergency response planning to ensure more effective and targeted flood resilience measures for urban areas facing increasingly frequent extreme precipitation events.

Spatiotemporal Variation in Extreme Climate in the Yellow River Basin and its Impacts on Vegetation Coverage

Global warming and extreme climate events (ECEs) have grown more frequent, and it is essential to investigate the influences of ECEs on vegetation in the Yellow River Basin (YRB) and other environmentally fragile areas. This study was based on data from 86 meteorological stations in the YRB for the period 2000–2020. Twenty-five extreme climate indices (ECIs) were chosen, encompassing four dimensions: extreme value, intensity, duration, and frequency. The trend analysis approach was used to examine the spatiotemporal characteristics of extreme climate conditions. Additionally, geographical detectors and Pearson correlation analysis methods were employed to quantitatively assess the influence of ECEs on the Normalized Difference Vegetation Index (NDVI). The Multiscale Geographically Weighted Regression (MGWR) method was adopted to analyze the regression of twenty-five ECIs. The findings revealed the following: (1) Over the last 21 years, there has been a distinct rise in both the extreme precipitation indices (EPIs) and the extreme temperature indices (ETIs). (2) The spatial distribution of the NDVI throughout the year displayed the characteristic of being high in the south and low in the north. The annual NDVI demonstrated a noteworthy increase at a rate of 0.055/decade, with the enhancement encompassing an extensive area of 87.33%. (3) The investigation revealed that EPIs, including PRCPTOT, R10mm, CWD, R95p, and CDD, had explanatory values surpassing 0.4. This implied that the intensity, frequency, and duration of extreme precipitation played pivotal roles in steering vegetation alterations in the YRB. (4) The correlation between the EPIs and vegetation was greater than the ETIs. Grassland meadows exhibited greater sensitivity to precipitation than woody plants. The EPIs (excluding CDD and SDII) and the ETIs (TXn) displayed a substantial positive correlation with the NDVI in regions hosting grasslands, broadleaf forests, and shrubs. Desert vegetation and cultivated plants were less affected by ECEs. This study underscores the importance of the interplay between extreme climate and vegetation in the YRB. Additionally, it provides a scientific basis for formulating environmental safeguarding strategies.

Operational Risk Assessment of Check Dams in Ningxia Considering the Impact of Extreme Precipitation in the Future

To analyze the operation risk of check dams under extreme precipitation conditions, taking Ningxia area as an example, this paper carried out a risk assessment of check dams under extreme precipitation conditions in Ningxia through data collection, hydrological statistics, numerical simulation, and other methods. The conclusions are the following: (1) By the end of 2020, about 40% of the silt reservoir capacity of check dams in various water and soil conservation zones in Ningxia has been accumulated. During 1966–2020, the extreme precipitation and frequency of extreme precipitation in Ningxia increased while the intensity of extreme precipitation decreased. The extreme precipitation in Ningxia increased year by year and lasted longer. (2) Under two future scenarios of RCP4.5 (the full name of RCP is Representative Concentration Pathway) and RCP8.5, the extreme precipitation threshold in Ningxia is gradually decreasing from south to north. Extreme precipitation in the future will bring high risk to the operation of check dams in Ningxia. The results of this paper can provide a scientific basis for the operation and management of check dams in Ningxia.

Spatial and Temporal Variability Characteristics and Driving Factors of Extreme Precipitation in the Wei River Basin

As global climate change intensifies, the global atmospheric circulation process is undergoing significant changes, and the local water vapor pattern has also changed. This study takes the Wei River Basin as the research area. Firstly, an evaluation index system for extreme precipitation was established, and the time-series characteristics of the magnitude, frequency, and duration of extreme precipitation were analyzed. Statistical methods were used to analyze the non-consistency in time-series changes in extreme precipitation indicators. Using spatial heterogeneity analysis methods, the spatial variation differences in extreme precipitation in the Wei River Basin were identified. This study selected the El Niño-Southern Oscillation (ENSO) index, global land-ocean temperature index (LOTI), and land surface temperature (LST) index to quantitatively evaluate the impact of climate change on regional extreme precipitation and analyzed the correlation between temperature and extreme precipitation, identifying the key driving factors of extreme precipitation changes. The conclusions of this study are as follows: (1) The southern region of the Wei River Basin experiences more frequent and intense precipitation events, while the northern region experiences relatively few. (2) From 1981 to 2021, the intensity, frequency, and duration of precipitation events in the Wei River Basin gradually increased, with the most significant increase in extreme precipitation in the Guanzhong Plain. (3) Global climate change has an important impact on precipitation events in the Wei River Basin. The increase in the ENSO, LOTI, and LST indices may indicate an increase in the probability of drought and flood events in the Wei River Basin. The relationships between extreme precipitation and temperature present a peak structure. This conclusion is helpful to better understand the impact of climate change on extreme precipitation in the Wei River Basin and provides some support for the response to extreme meteorological events under the background of future climate change.

The impact of extreme precipitation on nutrient runoff

AbstractAgriculture remains a leading source of water pollution in the United States, and climate change may exacerbate this relationship. We quantify increases in nutrient runoff following extreme precipitation events, showing that spikes are higher in regions with crop and livestock production. The spike per head is smaller around large‐scale livestock production, relative to small‐scale, and cover crops mitigate runoff. Legacy nutrients enter the surface water following extreme precipitation, regardless of current activity. We shed light on practices to protect water quality with more frequent extreme precipitation events and demonstrate the importance of including these events in empirical models of water quality.

Computational hydraulics and hazard assessment of flooding on underground staircases

Underground flooding is intensifying due to urban expansion and more frequent extreme precipitation. Staircases are crucial for accessing underground spaces and evacuation during floods and it is of both academic and practical value to investigate how floodwater and the induced hazard evolve over underground staircases. This study examines flood dynamics on underground staircases and its relationship with staircase characteristics through a series of numerical experiments using a two-dimensional (2D) hydrodynamic model. The study also uncovers how staircase design influences flood hazard levels. Results indicate that shorter or higher steps lead to shallower water depths but higher flow velocities. The branch staircase experiences smaller water depths and flow velocities than the main one. The presence of staircase transforms a subcritical flow into a supercritical flow. Except in extremely deep floodwaters, pedestrians are more vulnerable to sliding than toppling on staircases. The stability of the human body is greater on steps with longer length and lower height (26.56°) or the branch line of the junction type. The relative stability of the human body is not necessarily a guarantee of complete safety and must be analyzed in conjunction with the comprehensive safety factor.

Recent Climate Change in the Republic of Srpska and Bosnia and Herzegovina

The paper gives an overview of the observed climate change in the Republic of Srpska and Bosnia and Herzegovina; primarily the changes in air temperature and precipitation regime. In the period 1961‒2015 the positive trends of mean, maximum and minimum annual and seasonal air temperatures were determined, which were most pronounced in the summer season, whereas in the autumn season there is only a slight upward trend of temperatures. Warming is most pronounced in the northern part of the territory, whereas the increase is much lower in the higher parts of the Herzegovina region. Unlike air temperature, precipitation trends are, both seasonally and regionally, very variable and of different signs (positive and negative), but mostly insignificant. However, in some areas, the interannual variability of precipitation and the frequency of extreme precipitation have increased. In addition, the paper presents the results of research on possible climate change (based on expected changes in air temperature and precipitation) by the end of the 21st century in the Republic of Srpska and Bosnia and Herzegovina according to the climate scenario RCP8.5. The results indicate more pronounced climate change related to increasing annual temperatures up to 5 °C and reducing annual precipitation by up to 30%, whereas the deficit in the summer season (June, July and August) could go up to 40% by the end of the 21st century. Such changes point to the serious problem of drought and water scarcity and the need for more significant integration of climate change issues into planning and strategic documents.

Seribu islands in the megacities of Jakarta on the frontlines of the climate crisis

Jakarta, the biggest city in Indonesia, has one district that consists of hundreds of islands that face severe climate hazards called the Seribu Islands complex. This study explores the evidence of local climate trends, the potential impact, and its policy intervention on Seribu Islands, which are classified as small island states and widely recognized as being especially at risk from climate change, threatening their economic and social growth. Long-term in-situ climate data, satellite data, interviews with local stakeholders, and literature reviews were utilized to conduct an exploratory descriptive analysis. The result revealed that Seribu Island experienced a 2.2°C increase in minimum temperature from 1980 until 2021, 3.5-fold of the frequency of extreme temperature and precipitation, 4.17 mm/year of sea level rise, and 10.8 ha land expansion in the densest island. Moreover, about 67% of the inhabitant’s islands were occupied by built-up areas that cover more than 50% of the region. Further, under the worst-case SLR scenario, about 58.4% of the area will be affected, and about 29 islands will disappear. This evidence was also reinforced by every single local respondent’s viewpoint who felt that climate change is occurring in the region. Even though the region faces a severe threat of climate change, the issue of climate change adaptation has not been mainstreamed yet into their local policy. Therefore, the urgency of a real-time climate ground station, a real-time early warning system, and establishing a Regional Disaster Management Agency (BPBD) at the district level have yet to be addressed. Furthermore, the knowledge gained from such case studies is outlined, along with some scientific evidence that may assist small island states in better fostering the opportunities provided by climate change adaptation.

The increase in extreme precipitation and its proportion over global land

Changes in extreme precipitation (EP) have a significant impact on the ecology and sustainable development of most regions, especially when considered against a backdrop of global warming. Using trend analysis and other methods, we analyze the changes in nine extreme precipitation indices (EPIs), looking at the proportion of EP in total precipitation from the perspectives of intensity, frequency, and duration. We also utilize a geo-detector method to investigate the impacts of 15 climate factors on EPIs. Our results indicate that although EP and their proportions show an overall increasing trend on a global scale, they had undergone a process of initial decrease followed by increase over the past approximately 70 years. And this overall global increases are charged by the significant increases happened in Northern Hemisphere and western of South America, especially EP intensity and frequency indices, and their proportion. Whereas CDD shows an opposite trend in spatial distribution, the CWD is decreasing globally. The EPIs and their proportions are all highest in the low elevation belt (≤2000 m), followed by the high elevation belt (≥4000 m), and lowest in the mid-elevation belts (2000-4000 m). Most of them have returned to or exceeded the levels of the mid-20th century in all three elevation belts. Only CWD shows a decreasing trend, which indicates that more EP amounts are occurring with less precipitation duration. In some arid areas, this makes it possible that a short period of precipitation may complete the total amount of precipitation for that year. Global temperature is proven to be the most important factor influencing the EPI globally, and followed by the temperature of each region. And the regions of high latitudes of the Northern Hemisphere and Antarctica which are greatly influenced by global temperature demonstrate the Polar amplification effect. The East Atlantic-West Russia Pattern, Atlantic Multi-Decadal Oscillation, and El Nino-Southern Oscillation indices are the secondly important factors leading to changes in the proportion of global EP. At the same time, we also find that the influence of non-monsoon factors on EP is gradually strengthening. This study clarifies changes in EP globally and in various regions, which will help provide a scientific reference for preventing disasters caused by extreme climate change.

The Multi‐Scale Interactions of Atmospheric Phenomenon in Mean and Extreme Precipitation

AbstractClimate change increases the frequency and intensity of extreme precipitation, which in combination with rising population enhances exposure to major floods. An improved understanding of the atmospheric processes that cause extreme precipitation events would help to advance predictions and projections of such events. To date, such analyses have typically been performed rather unsystematically and over limited areas (e.g., the U.S.) which has resulted in contradictory findings. Here we present the Multi‐Object Analysis of Atmospheric Phenomenon algorithm that uses a set of 12 common atmospheric variables to identify and track tropical and extra‐tropical cyclones, cut‐off lows, frontal zones, anticyclones, atmospheric rivers (ARs), jets, mesoscale convective systems (MCSs), and equatorial waves. We apply the algorithm to global historical data between 2001–2020 and associate phenomena with hourly and daily satellite‐derived extreme precipitation estimates in major climate regions. We find that MCSs produce the vast majority of extreme precipitation in the tropics and some mid‐latitude land regions, while extreme precipitation in mid and high‐latitude ocean and coastal regions are dominated by cyclones and ARs. Importantly, most extreme precipitation events are associated with phenomena interacting across scales that intensify precipitation. These interactions are a function of the intensity (i.e., rarity) of extreme events. The presented methodology and results could have wide‐ranging applications including training of machine learning methods, Lagrangian‐based evaluation of climate models, and process‐based understanding of extreme precipitation in a changing climate.

Spatiotemporal variability of precipitation concentration in Pakistan

AbstractPrecipitation is a meteorological variable that plays a vital role in determining water resources and managing water risks. The intensity and frequency of precipitation extremes have increased in recent years; however, the changes in precipitation regimes across Pakistan remain unclear. This study analysed spatial and temporal changes in the precipitation concentration index (PCI) and concentration index (CI) from 100 meteorological stations across Pakistan from 1981 to 2017. Using innovative trend analysis (ITA) and Pettitt's test, we detected trends and change points in the annual and wet season PCI and CI. Additionally, we examined the relationship between PCI/CI values and latitude and altitude. The results revealed that the CI and PCI ranged between 0.48–0.78 and 10–55, respectively, with higher values being more prevalent in the dry and hot zones of the country. The study established a linear relationship between PCI/CI values, latitude and altitude, with higher values at lower altitudes and a decrease in values from south to north. Most stations presented a significant positive ITA trend for PCI and CI from 1981 to 2017, with a change between 1985 and 1995, indicating an overall increase in heavy precipitation events in the area. These findings are crucial for disaster preparedness, water resource planning, the mitigation of drought and flood risks, and conservation efforts.