Average Rainfall Research Articles

Applicability of a Modified I-D Method for Predicting Slope Failure to Different Slopes

The authors have proposed a modified intensity–duration (I-D) method that incorporates field measurements of tensiometer to improve the accuracy of predicting the risk of slope failure. This method uses an indicator that considers the relationship of the duration from the time point at which the saturated zone is assumed to have formed to the average rainfall intensity during that period. The usefulness of this method has been verified, but its applicability to different slopes has not yet been investigated. Here, the authors collected long-term observations on a natural slope in Minamiashigara City, Kanagawa Prefecture, and examined the Modified I-D method using data on slope failures in the surrounding area. The authors also compared the results with plots of previous rainfall index (soil water index–accumulated rainfall in 60 min, effective rainfall amount with a half-life of 72 h–effective rainfall amount with a half-life of 1.5 h, and accumulated rainfall–accumulated rainfall in 60 min). The snake curves for rainfall events during slope failure and non-failure were clearly separated. The accuracy was high, confirming the applicability of the modified I-D method.

Topography Effects on Rainfall Characteristics in Bandung City and Cilacap Regency for the 2016-2020 Period

Topography and rainfall correlate with each other. Therefore, this study aims to determine the effect of topography on rainfall characteristicss in the Cilacap and Bandung areas. The research method used is a descriptive statistical analysis of average monthly, seasonal, and annual rainfall. In addition, time series and regression tests were carried out using the SPSS application. The data used is the daily rainfall data period of 2016–2020. The results of the descriptive analysis show that the variability of monthly rainfall in Bandung is higher than in Cilacap, with a value range that is 113.6–643.82 mm/month for Bandung and 92.1-355.56 mm/month for Cilacap. Global climate dynamics for instance apparent sun motion, Monsoon, ITCZ, ENSO, and IOD, as well as local weather systems like valley winds, also affect seasonal and annual rainfall variability in Bandung and Cilacap. The rainfall time series test produces values that are not stationary concerning the variance but stationary concerning the average. A simple linear regression test shows the effect of a topography of 55.2% on rainfall. The purpose of simple linear regression is to understand and model the relationship between two variables: the independent variable (topography) and the dependent variable (rainfall characteristics).

RAINFALL ANALYSIS FOR CREATING INTENSITY-DURATION-FREQUENCY (IDF) CURVE OF PONTIANAK CITY

Pontianak is a lowland area prone to flooding if it rains with high rainfall intensity. Analysis of the planned flood discharge is needed to overcome the flood problem. The design flood discharge analysis can be calculated using the rational method, which requires rain intensity data in terms of duration and frequency, which can be described as an IDF curve.This research was conducted by calculating the average daily maximum rainfall after conducting consistency and homogeneity tests on the rainfall data used and determining the selected distribution based on the results of statistical parameters. The rain design with various return periods is calculated with the desired distribution that matches Pontianak City. The rainfall intensity calculation uses the Mononobe method because the rainfall data owned is daily rainfall data.The analysis results show that the Log Pearson Type III distribution corresponds to the data distribution in Pontianak. From the IDF curve, it can be seen that high rainfall intensity lasts for a short duration; this can prove the general nature of rain that the faster the rain stays, the higher the rainfall intensity and vice versa. The IDF curve can assist in calculating the design flood discharge.

Analysis of Empirical Rainfall Data Covering 1979-2020 as a Guide to Agriculture and Water Resources Management in Ondo State, Nigeria

The aim of this paper was to evaluate daily empirical rainfall data covering 1979-2020 as a guide to agriculture and water resources management in Ondo, State, Nigeria by collecting data from the Nigerian Meteorological Agency, Abuja, using various standard methods. Results showed that, the area observed rainfall throughout the year with March (86.4 mm) as the rainfall onset, November (56.4 mm) was the cessation, double maximum rainfall occurred in July (254.2 mm) and September (282.1 mm) with the climatological mean of 1752.2 mm. Also, the percentage (%) difference rainfall showed seven (7) positive and four (4) negative occurrences. The highest positive % difference occurred in September (10.4), while the lowest occurred in July (2.6). The highest negative % difference was -26.5 (November), while the lowest was -5.9 (August). The stations deviation from zonal average monthly rainfall showed that, Igbokoda, Ilaje LGA deviated in all the months negatively, while Okitipupa, Okitipupa LGA and Oka-Akoko, Akoko South West LGA deviated positively in eleven (11) months each. The study concluded that, rainfall varied and had declined generally over the study area. Hence, it was recommended that, the Seasonal Climate Prediction (SCP) by Nigerian Meteorological Agency (NiMet) should be down-scaled early to serve as a guide to farmers and hydrologists; irrigation should be encouraged; hybrid crops should be cultivated and more water reservoirs should be constructed.

Geospatial Mapping of Groundwater Potentiality in Sooriyawewa Divisional Secretariat Division by Utilizing GIS

The dry zone of Sri Lanka is affected by drought conditions owing to a lack of rainfall. Hence, mapping the distribution of groundwater potential zones is vital for water management. The Hambantota district, which is in the dry zone is a severely afflicted area due to lack of rainfall, and Sooriyawewa divisional secretariat area faces water scarcity. Therefore, this study aims to map groundwater potentiality in the Sooriyawewa divisional secretariat division using a geographical information system. For this study, spatial interpolation techniques, weighted overlay analysis, georeferencing, and digitizing methods were used. In this study, the annual average rainfall, geology, geomorphology, drainage density, lineament density, land use land cover, slope, and soil maps were prepared, and integrating those maps, the final groundwater potential zones map was prepared by using ArcMap 10.5 software. The study found that there were no high-potential groundwater zones in the Sooriyawewa divisional secretariat division and it already consists of low and moderate ranges. Therefore, the final groundwater potential zone map was categorized as very low, low, and moderate. The Percentages of area Coverage according to classes as, very low 2%, low 91%, and moderate 7%. This study can be highly helpful in identifying the groundwater potential zones in the Sooriyawewa divisional secretariat division and in preventing water scarcity because identified groundwater potential zones can be used for effective water management and provide essential information to responsible authorities for decision-making. Furthermore, the identified potential zones can be used for rainwater harvesting and can be used properly for future consumption.

Remote sensing-based drought hazard monitoring and assessment in a coastal plain: A principal component approach

Accurate drought information is essential for preventing agricultural and societal losses. The indicators of how severe a drought is the deficiency in precipitation, soil moisture, and vegetation stress. The indicators were evaluated using the Precipitation Condition Index (PCI), Vegetation Condition Index (VCI), and Temperature Condition Index (TCI).The indices were combined using Principal Component Analysis to create the Synthetic Drought Index (SDI) for the evaluation of drought severity. The indices were estimated using multi-source remote sensing data from the Tropical Rainfall Measuring Mission (TRMM) and Operational Land Imager (OLI) of various years. Temporal analysis showed that the district is drought-prone and deficiency of 65% of precipitation in northeast monsoon of 2016 and below average non-monsoon rainfall in 2017, caused drought and affected 223.5 Km2 in 2017. Below average precipitation in northeast monsoon of 2018 and below average non-monsoon rainfall in 2019, caused drought and affected 423 Km2 in 2019. The northeast coastal regions of Ottapidaram, Thoothukudi, and Vilathikulam taluks of the district were more severely prone to drought. Failure of monsoon is the root cause of water deficit in water bodies. The semi-arid coastal climate accelerates the evaporation of water in water bodies and causes soil moisture deficit that leads to drought in the coastal district. A sequential evaluation of this index can be used to identify the onset of drought and mitigate the effect of drought.

Hydrogeochemical study of groundwater in arid and semi-arid regions of the Infracenomanian aquifers (Cretaceous Errachidia basin, Southeastern Morocco). Using hydrochemical modeling and multivariate statistical analysis

Groundwater in the Cretaceous Errachidia basin, located in the southern part of Morocco, is crucial in supporting the region's main economic activities, such as farming. This arid region faces multiple challenges, including an average annual rainfall of less than 80 mm/year, intense agricultural activities, high evaporation, and extremely high evapotranspiration rates up to 1580 mm/year. Therefore, the hydrogeochemical study focuses on the Infracenomanian aquifers in the Cretaceous Errachidia basin. The goal is to evaluate the sustainable use of saline lands and brackish water, particularly assessing water resources and sustainable socioeconomic development in southeastern Morocco. In June 2021, 20 samples were collected and analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS) and major ions. The hydrogeochemical parameters were analyzed using multivariate statistical methods. Statistical techniques such as Piper's trilinear diagram analysis of hydrochemistry types, Gibbs diagram analysis, The HFE diagram and ion correlation analysis were used to examine the origins of the main ions in the groundwater and to determine the source of the salinization processes in the groundwater.The findings revealed a strong positive correlation between TDS and the spatial distribution of major ions (Na+, Ca2+, Mg2+, Cl−) and EC, revealing high mineralization in the study area. The main cations in groundwater are Na+ and Ca2+, while the main anions are Cl−. The elevated concentrations of Cl− and Na+ are due to the evapotranspiration of irrigation water. Furthermore, the hydrochemical facies types are predominantly sodium chloride (Na–Cl), followed by calcium chloride (Ca–Cl) and a mix of calcium and magnesium chloride facies (Ca–Mg–Cl). These analyses indicate that the hydrochemistry of groundwater in the study area is primarily influenced by water-rock interactions, such as the dissolution of sedimentary rocks, soil leaching through gravity irrigation, and evaporation in the region. Moreover, the analysis using the Gibbs diagram indicates that evaporation is the primary hydrogeochemical process that shapes the chemical composition of the groundwater in the area under study.

Co-evolution among soil thickness, epikarst weathering degree, and runoff characteristics on a subtropical karst hillslope

Carbonate landscapes make up one-fifth of the terrestrial land area, a better understanding of the coupling relationship between the soil–epikarst form and hydrological function is imperative for hydrology and landscape evolution modeling. In this study, we monitored a total of 158 rainfall-runoff events on a karst slope between 2019/4 and 2022/5 in southwest China, while simultaneously examining the soil–epikarst architecture (924 pairs of soil thickness and epikarst weathering degree). The results indicated that soil thickness increased with the underlying epikarst weathering degree, and soil thickness was positively correlated with epikarst thickness (P<0.001). Additionally, a significant positive relationship (P<0.001) was observed between surface runoff (SR) and soil thickness, as well as a significant negative relationship (P=0.0018) between subsurface runoff (SSR) and soil thickness. These findings imply the dominance of SR and SSR (under normal rainfall conditions) in runoff plots with deep soil layers and thin soil layers, respectively. The soil thickness threshold at which the hillslope discharge shifted from being SSR-dominated to SR-dominated was approximately 50 cm. Nonetheless, a positive relationship was found between SR and SSR under extreme rainfall events, indicating the establishment of hydrological connectivity between the surface and subsurface. Moreover, the hillslope discharge when the rainfall depth is lower than 50 mm is primarily composed of either SR or SSR from different plots. In other words, the hillslope discharge is typically influenced by both SR and SSR when the rainfall depth exceeds 50 mm. We finally proposed a positive feedback loop among soil thickness, epikarst weathering degree, and the hydrological function of the soil–epikarst system (water storage and release). These findings enhance our understanding of the complex interactive relationships in hillslope hydrology by illuminating the physical links between critical zone structures and hydrological processes on the karst slope.

Geospatial analysis of the hospitalisation rate of patients with rheumatoid arthritis in Hunan: a cross-sectional Chinese study

ObjectiveLittle is known about spatial variability of hospitalisation rate (HR) of patients with rheumatoid arthritis (RA) worldwide, especially in China.MethodsA cross-sectional study was conducted among patients with RA admitted to...

Centering community-based knowledge in food security response and climate resilience in southern Madagascar

ObjectiveIncreasingly unpredictable shifts in climate are triggering public health crises globally. Southern Madagascar is particularly vulnerable to climate impacts, despite contributing to only 0.2% of global emissions. Though endemic in Madagascar, climate impacts such as below average rainfall have increased the severity of droughts, putting over half of the population in southern regions at risk of being food insecure in 2022. The following review examines: How can interventions surrounding the current food emergency in southern Madagascar center community-based knowledge in their strategies? Through a social-ecological approach, this review aims to holistically discuss the complexity of the climate and food crises in this region, which is a topic that has not been widely covered in published review articles thus far.MethodsWe took a comprehensive and social-ecological approach by analyzing research pertaining to the impacts of colonial history, politics, economy, and culture on the current climate, ecology, and food systems of southern Madagascar.Main findingsMany current strategies to mitigate climate impacts and food security fail to incorporate community-based knowledge, leading to inequitable and ineffective interventions. Researchers who prioritize historical and cultural context illustrate how local knowledge may serve as a protective factor against climate impacts.ConclusionsAs climate shifts exacerbate public health crises, aid organizations must center community perspectives in their interventions to foster equitable and sustainable outcomes.

IMPACT OF TROPICAL CYCLONE SEROJA ON RAINFALL AND WIND SPEED IN EAST NUSA TENGGARA PROVINCE

Tropical cyclone phenomenon can give impacts such as heavy rain, strong winds, and high waves around its growth area. One of the tropical cyclones that has occurred is Seroja Tropical Cyclone which formed in the Sawu Sea on April 3, 2021. Therefore, this study aims to determine the effect of Seroja Tropical Cyclone on rainfall and surface wind speed in East Nusa Tenggara Province and the percentage comparison of rainfall and wind speed during the Seroja tropical cyclone event with the normal value of rainfall and surface wind speed over a 10-year period. The data used are daily rainfall and surface wind speed data during the Seroja tropical cyclone event, namely April 3 to 12, 2021 and daily average rainfall and wind speed data in April for 10 years in several affected districts in East Nusa Tenggara Province. Data processing is done by calculating the percentage comparison of rainfall and wind speed during the Seroja Tropical Cyclone event with normal rainfall and wind speed in several regions in East Nusa Tenggara. Based on the analysis, heavy to extreme rainfall and strong winds were found in several districts at a radius of about 400 km from the center of the cyclone. Although the category of this tropical cyclone is low, it is able to give impacts in the form of heavy to extreme rainfall and strong winds in the surrounding area. So it can be concluded that the tropical cyclone category does not directly affect rainfall and wind speed in an area, but the distance between the area and the center of the tropical cyclone is more influential in increasing rainfall and wind speed in an area. This is also proven by Sumaja's research in the case of tropical cyclones LUA and Narelle.

Extreme precipitation causes divergent responses of root respiration to nitrogen enrichment in an alpine meadow

Grassland roots are fundamental to obtain the most limiting soil water and nitrogen (N) resources. However, this natural pattern could be significantly changed by recent co-occurrence of N deposition and extreme precipitations, likely with complex interactions on grassland root production and respiration. Despite this nonlinearity, we still know little about how extreme precipitation change nonlinearly regulates the responses of root respiration to N enrichment. Here, we conducted a 6-year experiment of N addition in an alpine meadow, coincidently experiencing extreme precipitations among experimental years. Our results demonstrated that root respiration showed divergent responses to N addition along with extreme precipitation changes among years. Under normal rainfall year, root respiration was significantly stimulated by N addition, whereas it was depressed under high or low water. Moreover, we revealed that both root biomass and traits (i.e. specific root length) were critical mechanisms in affecting root respiration response, but their relative importance changed with water condition. For example, specific root length and specific root respiration were more dominant than root biomass in determining root respiration response under low water, or vice versa. Overall, this study comprehensively reveals the nonlinearity of root respiration responses to the interactions of N enrichment and extreme water change. These new findings help to reconcile previously conflicting results that obtain in a specific episode of water gradient, with important implications for understanding grassland belowground carbon dynamics in facing combined N deposition and extreme precipitation events.

A cluster of leptospirosis cases associated with crocodile workers in the Northern Territory, Australia, 2022.

Leptospirosis is a worldwide zoonotic waterborne disease endemic in tropical and subtropical climates. Outbreaks have been observed in the Northern Territory (NT) of Australia. We briefly described the epidemiology of leptospirosis in the NT between 2012 and 2022, and undertook an investigation of a cluster of three leptospirosis cases observed in crocodile workers between January and December 2022 in the Top End of the NT. A descriptive case series was conducted to investigate the cluster; all three cases were male and non-Aboriginal with a median age of 46.5 years; none took chemoprophylaxis; only one of the three cases reported wearing appropriate protective attire; all reported receiving limited to no education about personal protective measures from their associated workplaces. Higher than average rainfall in both February and December 2022 likely contributed to the increased risk of infection in those months. Changing climate patterns are likely to result in more frequent periods of heavy rain, and risk of contracting leptospirosis in the NT may increase, particularly for those who work in wet and muddy conditions. Promoting the use of protective workplace clothing and equipment, the use of waterproof dressings for skin abrasions, regular hand hygiene, and the consideration of chemoprophylaxis in certain circumstances may prevent future cases.

Sensitivity of runoff due to changes in the characteristics of the water balance in the Danube River region

Abstract Climate change is presently a widely discussed subject in relation to alterations in water storage capacity and the components of the hydrological balance within catchment areas. This research study was directed at two main objectives: 1. The indirect estimation of long-term mean annual runoff using an empirical model; 2. The determination of changes in the annual runoff regime of fifty Danube sub-basins. Monthly areal precipitation, discharges, and air temperature data from 1961 to 1990 were collected for selected headwater sub-basins of the Danube River. In the first part, Turc-type empirical equations for the estimation of the long-term average annual runoff R in the Danube basin were employed. The parameters of the empirical equations were determined through nonlinear regression. Given the underestimation of the actual (territorial, balance) evapotranspiration ET values determined from the balance equation, the precipitation totals were corrected by +10%. With a 10% increase in precipitation, the values of balance ET reached the values ET determined by the Budyko–Zubenok–Konstantinov method. In the second part, fifty equations for the estimation of changes in the average annual runoff, depending on increases in the air temperature and changes in the annual precipitation separately for each of the 50 sub-basins, were established. In conclusion, the results suggest that, on average, a 100 mm increase in the average annual rainfall in the Danube River headwater sub-basins, will cause a 50 mm increase in outflow, and a 1 °C increase in the average annual air temperature will lead to a 12 mm decrease in runoff.

ASSESSMENT OF TEMPORAL VARIABILITY OF TEMPERATURE AND PRECIPITATION TRENDS IN KARGI, MAIKONA, DAKABARICHA AND SOLOLO WARDS OF MARSABIT COUNTY, KENYA

&lt;p&gt;&lt;strong&gt;Background.&lt;/strong&gt; Climate change is a global phenomenon, with varying indicators and impacts from one region to another. The impacts of the changing climate are high in developing countries that are mainly dependent on climate-driven economic sectors such as pastoral and agro-pastoral livelihoods. &lt;strong&gt;Objective.&lt;/strong&gt; Analyze the temporal trend, the variability in temperature and precipitation, and the relationship between both parameters to determine the influence of the El Niño phenomenon in Marsabit County, Kenya, from 1981 to 2021. &lt;strong&gt;Methodology.&lt;/strong&gt; Daily rainfall and temperature data for the four study locations (Maikona, Kargi, Dakabaricha, and Sololo) were obtained. The analysis of extremes was the main method used in the analysis of the temporal and spatial variability of rainfall and temperature to establish the frequency and magnitude of climate variability in the study area. The seasonal mean plus or minus 1 Standard deviation for the entire period of study was used in the analysis of extremes. &lt;strong&gt;Results.&lt;/strong&gt; Findings from trend analysis showed that rainfall trends have significantly increased in Marsabit County. Further, results on seasonal trends and variability of rainfall showed that March-April-May rainfall has been decreasing over the years. Below average rainfall has been experienced in Maikona in 2000 and 2011 with a magnitude of -42.9 mm, and -39.3 mm, respectively, while below average rainfall has been experienced in Kargi in 2000, 2009, 2011, and 2012 with a magnitude of -41.7 mm, -24.2 mm, -35.3 mm, and -34.3 mm, respectively. Analysis of the temperature trends and variability showed that both night and day temperatures have significantly increased over the years in Marsabit County. The magnitude of warming was found to be double that of cooling. The regression analysis further showed that there exists a negative correlation between temperatures and rainfall, implying that generally, rainfall decreases with increasing temperatures. &lt;strong&gt;Implications.&lt;/strong&gt; This finding is important because it could help policymakers and people working on development in Marsabit County see what temperature and precipitation changes are happening locally. This could help them plan for climate change better. Both pastoral and agro-pastoral areas have been affected by both El Niño and La Niña activities, with the El Niño years recording the highest amounts of rainfall while the La Niña years recording the lowest amounts. &lt;strong&gt;Conclusion&lt;/strong&gt;&lt;strong&gt;s&lt;/strong&gt;&lt;strong&gt;.&lt;/strong&gt; This study recommends the use of rainwater harvesting during the October to December Season to take advantage of the increasing Trends and flood episodes associated with high magnitudes and frequencies of above average rainfall and use the same to cope with reduced rainfall in the March to May season. &lt;/p&gt;

Paradoxical behaviour of rainfall and temperature over ecologically sensitive areas along the Western Ghats.

Initial reports signify some specific isolated locations in different latitudes, revealing a paradoxical increase in both heavy and very heavy rainfall events and also an increment in total, i.e., in both rainfall and temperature, over ecologically sensitive areas along the Western Ghats (WG). This paper presents a coherent study of the full-scale of daily rainfall and temperature over 27 well-spaced stations in the study area to determine its extent and investigate whether or not this contradictory behaviour is real. Also, an attempt has been made to assess the differential behaviour of rainfall, temperature, and heavy rainfall events in association with land use and land cover change (LULC). The analysis revealed that rainfall and temperature over the study area are increasing, whereas heavy rainfall events have increased during 1981-2020 with strong peaks after 2000 around 18-19°N (Mumbai metropolitan region), 14-16°N (mining and quarrying regions in Goa), and 9-12°N (a narrow strip of land spanning across the coastal towns of Karnataka and Kerala) latitudes. The majority of the rainfall excess years coincided with El Nino years, indicating that El Nino does not affect rainfall negatively. However, rainfall over the WG is influenced by local relief and cascading topography. The spatial pattern of average annual rainfall shows a decreasing trend from south to north because the elevation and span of rainfall occurrence are higher in the southern part of WG. The findings of the current research will help in building a strategy to address trends and patterns of climatic variables in association with LULC.

PENELUSURAN BANJIR KOLAM RETENSI SUSUKAN KECAMATAN UNGARAN TIMUR KABUPATEN SEMARANG

Floods are natural disasters that occur in an area due to the inability of drainage channels or many rivers, in overcoming the flooding problem that occurred a problem that occurred in, Susukan District, East Ungaran District, the Semarang Regency Government has taken action by constructing a retention pond. This research aims to analyze the capacity of the retention pond.This research required data: topographic data, rainfall data and geotechnical soil data. The analysis carried river watershed and hygrological analysis which includes: determining average rainfall, planned flood discharge, flood routing and calculating the stability of the spillway building.From the results of the hydrological analysis, the flood discharge value obtained using the gamma I unit hydrograph method for a 5-year return period was 21,53 m3/second. In flood investigations, an outflow value of 21.11 m3/second was obtained with an overflow height of 1,65 m.

Impact of rainfall and vapor pressure deficit on latewood growth and water stress in Douglas-fir in a Mediterranean climate

Both elevated temperature and reduced precipitation have been related to growth declines in Douglas-fir (Pseudotsuga menziesii) in the northwest U.S. However, the impact of high vapor pressure deficit (VPD) on Douglas-fir growth and physiological stress is not fully understood. We investigated how inter- and intra-annual rainfall and VPD correlated to the radial growth and carbon isotope signature (δ13C) of latewood for ∼ 50-year-old Douglas-fir trees in the western Cascade Mountains in Oregon. Latewood δ13C reflects variation in stomatal restriction of photosynthetic gas exchange and, therefore, was used as a proxy for the relative degree of physiological water stress. We cored three trees at each of nine sampling sites (n = 27 trees) and used a moving window analysis to test the period of the year in which VPD and rainfall best predicted mean latewood radial growth and δ13C. Latewood growth, measured as the basal area increment, was more sensitive to daytime VPD than the timing and amounts of rainfall, especially in early summer. In contrast, δ13C was equally sensitive to the average daytime VPD and total rainfall during spring and summer. We used the results of the moving window analysis in a linear mixed effects model to test how the effect of VPD and rainfall on yearly latewood growth and δ13C differed among our nine sites. We found no evidence for statistical differences in the effects of VPD and rainfall on growth (p = 0.93 and p = 0.91) or δ13C (p = 0.31 and p = 0.81) among our nine sites. However, the marginal effects of VPD on latewood growth at each site were weakly related to soil moisture deficits at 100 cm suggesting that site-to-site differences in soil moisture availability may be important in buffering the negative effects of seasonal aridity on growth. In contrast, there was no evidence that soil moisture differences among sites influenced the marginal effects of VPD on latewood δ13C. We conclude that increases in VPD during summer are likely to reduce latewood growth and increase water stress in Douglas-fir in the Pacific Northwest region. However, more research is needed to better understand the magnitude of this effect across sites with variable subsurface water storage and microclimate.

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

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

Flash-flood susceptibility modelling in a data-scarce region using a novel hybrid approach and trend analysis of precipitation

ABSTRACTRecently, the incidence of heavy rainfall events and associated flash floods have encouraged us to investigate long-term trends in extreme rainfall and flash flood vulnerability mapping. Thus, in this study, a hybrid model was designed by integrating weight of evidence and Naïve Bayes (WOE-NB) to identify areas in Uttarakhand prone to flash floods, and we compared its ability with that of AdaBoost. Furthermore, the significance of long-term rainfall trends was evaluated using Mann–Kendall, modified Mann-Kendall, and innovative trend analysis (ITA), and extreme rainfall events were examined for 51 years (1970–2020). Results showed the WOE-NB and AdaBoost had acceptable goodness of fit (area under the curve = 0.969 and 0.973, respectively). Moreover, ITA can identify some important patterns based on on-trend results that other tests cannot. The return period revealed about 97.54% of the flash floods were caused by normal rainfall, with 2.45% being caused by severely abnormal rainfall.