Precipitation Intensity Research Articles

Anthropogenic influence on precipitation in Aotearoa New Zealand with differing circulation types

This study quantifies the influences of anthropogenic forcing to date on precipitation over Aotearoa New Zealand (ANZ). Large ensembles of simulations from the weather@home regional climate model experiments are analysed under two scenarios, a natural (NAT) or counter-factual scenario which excludes human-induced changes to the climate system and an anthropogenic (ANT) or factual scenario. The impacts of anthropogenic forcing on precipitation are analysed in the context of large-scale circulation types characterized using an existing Self Organizing Map classification. The combined effect of both thermodynamics and dynamics are compared with values expected from the Clausius–Clapeyron (C–C) relation. Changes in the precipitation intensity due to greenhouse gas-forced temperature rise are lower than the expected C–C value. However extreme precipitation changes approach the C–C value for some circulation types. Specifically westerly flows enhance precipitation change across ANZ relative to the C–C rate, particularly over the West Coast. Conversely, northwesterly flows reduce the change over the North Island relative to the C–C value. Moreover, the wet day frequency generally reduces in the ANT scenario relative to NAT, reductions are largest on the West Coast of the South Island for westerly flows. Additionally, the frequency of days with extreme precipitation rises over ANZ for most circulation patterns, except in Northland and for northwesterly flows. This underscores the combined influence of dynamics and thermodynamics in shaping both precipitation intensity and frequency patterns across ANZ.

Quercus acutissima exhibits more adaptable water uptake patterns in response to seasonal changes compared to Pinus massoniana

BackgroundSeasonal precipitation variability significantly affects water use in forests; however, whether water uptake is adapted to changes in precipitation, particularly whether it could affect the coexistence of tree species, has rarely been quantified in forest systems. MethodIn this study, dual stable isotopes and the Li-6400 portable photosynthesis system were used to determine the water sources of a mixed conifer (Pinus massoniana) and broadleaf (Quercus acutissima) forest and changes in hydraulic characteristics during the dry and wet seasons in a southern hilly region of China. ResultsAlthough the hydraulic characteristics of P. massoniana were lower than those of Q. acutissima, it maintained a stable water source from the deep soil layer and a higher stomatal conductance (Gs), leading to a higher transpiration rate (Tr) during the growing seasons. Q. acutissima mainly absorbed water from deeper soil layers in the dry season and took up from shallow soil layers in the wet season. Its Gs values exhibited sensitivity to precipitation, while it maintained a lower Tr value during the growing seasons. The excessive water-use strategy observed in P. massoniana may confer weak drought-tolerance during higher frequency and more intense extreme precipitation events, whereas Q. acutissima may exhibit better ecological adaption to precipitation changes. ConclusionsThe overlap of water niches in mixed forests did not appear to affect the coexistence of tree species. The present study provides insights into reforestation and water management in the southern hilly regions of China.

The Dynamics of Vegetation Evapotranspiration and Its Response to Surface Meteorological Factors in the Altay Mountains, Northwest China

The Altay Mountains’ forests are vital to Xinjiang’s terrestrial ecosystem, especially water regulation and conservation. This study evaluates vegetation evapotranspiration (ET) from 2000 to 2017 using temperature, precipitation, and ET data from the China Meteorological Data Sharing Service. The dataset underwent quality control and was interpolated using the inverse distance weighted (IDW) method. Correlation analysis and climate trend methodologies were applied to assess the impacts of temperature, precipitation, drought, and extreme weather events on ET. The results indicate that air temperature had a minimal effect on ET, with 68.34% of the region showing weak correlations (coefficients between −0.2 and 0.2). Conversely, precipitation exhibited a strong positive correlation with ET across 98.91% of the area. Drought analysis, using the standardized precipitation evapotranspiration index (SPEI) and the Temperature Vegetation Dryness Index (TVDI), showed that ET was significantly correlated with the SPEI in 96.47% of the region, while the TVDI displayed both positive and negative correlations. Extreme weather events also significantly influenced ET, with reductions in the Simple Daily Intensity Index (SDII), heavy precipitation days (R95p, R10), and increases in indicators like growing season length (GSL) and warm spell duration index (WSDI) leading to variations in ET. Based on the correlation coefficients and their significance, it was confirmed that the SII (precipitation intensity) and R95p (heavy precipitation) are the main factors causing vegetation ET increases. These findings offer crucial insights into the interactions between meteorological variables and ET, essential information for sustainable forest management, by highlighting the importance of optimizing water regulation strategies, such as adjusting species composition and forest density to enhance resilience against drought and extreme weather, thereby ensuring long-term forest health and productivity in response to climate change.

Projected climatic exposure and velocities of precipitation extremes over India and its biogeographic zones

AbstractClimate change is leading to alterations in the dynamic and thermodynamic climate systems worldwide, including the Indian summer monsoon (ISM), which supports more than a billion population and drives the Indian economy. The anthropogenic climate change induces unprecedented transformations in the natural and ecological systems, such as the increased probability of precipitation extremes, changes in their frequency, duration and spatial variabilities. This current study aims to project the regional landscape‐based metric, velocity of climate change (VoCC) and associated climatic exposure regarding precipitation extremes (PEs) for India and its different biogeographic zones. The climate velocities of mean precipitation, 95th, 99.5th and 99.9th percentiles of precipitation for the ISM season are presented for the historical and three projected time slices under the RCP8.5 scenario. ROM, a state‐of‐the‐art regional earth system model over the CORDEX‐South Asia domain, was used in the study. It was observed that the intense and very intense rainfall (95th, 99.5th and 99.9th percentiles) was enhanced over most of the study region in the near‐ and mid‐future compared to the far‐future. The intense rainfall exhibited higher climate velocity than the mean and very intense precipitation in the near‐future. The southern part of the Indian subcontinent usually displayed positive VoCC values for the historical and near‐future time slices compared to the northern part of the Indian peninsula, particularly the intense and very intense precipitation. The climatic exposure for all‐India was also higher in the near‐ and mid‐future compared to the far‐future, especially for the intense rainfall followed by the mean and very intense rainfall. These results suggest the need for focusing the adaptation and mitigation measures towards managing the near‐term impacts of PEs in relation to the long‐term impacts, especially on the country's diverse flora.

Comparison of Climatology of Precipitation Diurnal Cycle in Kalimantan Deduced from Rain Gauge and IMERG Data

Abstract The diurnal cycle is repetitive pattern of changes in weather factors on land and oceans due to the Earth rotation. Kalimantan Island as the largest island in the Maritime Islands region has a complex rainfall pattern that is influenced by local factors and global circulation. The research was conducted to find out the climatological comparison of the diurnal cycle of rain in Kalimantan based on rain gauge data and Integrated Multi-SatellitE Retrievals for GPM Version 07 (IMERG V07) data for the period 2016 - 2022. Data validation using rain gauge data to validate and calibrate IMERG satellite data, improving the accuracy and reliability of satellite rainfall estimates. The diurnal cycle is evaluated through a Precipitation Amount (PA), Precipitation Frequency (PF), and Precipitation Intensity (PI) every hour. The results show that the maximum rainfall occurs in the afternoon and evening along the coast, and in the middle of the night and morning on the Kalimantan plains. Kalimantan has high rainfall intensity values at short rainfall durations, i.e. rain lasting less than 3 hours. This is expected to improve the quality of hydrometeorological disaster mitigation in Kalimantan.

Elevation-Dependent Snow Cover Dynamics and Associated Topo-Climate Impacts in Upper Indus River Basin

In the present study, Improved Moderate Resolution Imaging Spectro-radiometer (MODIS) snow cover product (MOYDGL06*) has been used to evaluate the snow cover area (SCA) in Kabul, Jhelum, and Indus river basins for the time period of 2003 – 2020 with available MODIS land surface temperature (LST), and CHIRPS (precipitation) with objectives to evaluate the spatio-temporal SCA, and climate variables with respect to different elevations analyzed from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model Version 3 (GDEM v3) and also to correlate the climatic variables with SCA. The results presented average annual SCA is around 50.7% – 64.7% in sub-basins of UIB, further it has been observed that SCA is decreasing on annual and seasonal timescale in all three basins. Elevation-dependent SCA, temperature, and precipitation presented a mix of trend on annual, seasonal, and monthly timescale at lower and higher altitude in all selected basins. Moreover, it was noticed that topography (slope, & aspect) also influences the SCA in the region. Furthermore, it has been examined that temperature has significant inverse relationship with SCA at middle and higher altitude in Indus, while in Kabul, and Jhelum no significant relationship observed at extreme lower and higher altitudes. It is also evident from relationship between SCA and climate variable that temperature is significantly responsible for decreasing trend of SCA rather than intense precipitation in all three river basins. Thus, all these elevation-dependent changes can improve our hydrological understanding which can have a considerable implication for hydrology, climate science, water resource management and socio-economic activities.

A rainfall prediction model based on ERA5 and Elman neural network

The heightened frequency and intensity of heavy rainfall, brought about by global climate warming, significantly affect various regions. Rainfall prediction plays a pivotal role in ensuring societal security and fostering development. There has been limited exploration of the impact of input parameters on the accuracy of rainfall predictions. Despite the advantages of Elman neural network models in handling non-linear relationships and spatiotemporal data, their application in weather forecasting is restricted. This paper assesses the accuracy of the European Centre for Medium-Range Weather Forecasts Reanalysis v5 (ERA5) with a dataset from meteorological stations. It introduces a novel rainfall forecasting model based on the Elman neural network and ERA5 reanalysis data. The study also identifies optimal input parameters through factor correlation analysis. Experimental results showcase the precision and stability of ERA5 across various rainfall conditions. Meteorological parameters, such as Precipitable Water Vapor (PWV), exhibit noticeable correlations with temporal variables and precipitation volume. The seven-factor model, including PWV, Zenith Tropospheric Delay, temperature, relative humidity, day-of-year, and hour of day, outperforms in precision evaluation. It achieves a mean critical success index of 57.06 %, a correct forecast rate of 91.39 %, and a false alarm rate of 39.48 %. This rainfall forecasting model introduces a novel approach and empirical research to enhance predictive accuracy, holding significant implications for the amelioration of meteorological alert systems, risk mitigation, and the safeguarding of life and property.

Quantification of nanoscale precipitation in AA7050 using X-ray scattering, electron microscopy and automated particle counting techniques

Material strength is dependent on several factors, including precipitation strengthening, which is the main strengthening mechanism in AA7050 aluminum alloys. These alloys contain numerous nanometer-scale precipitates that occur throughout grains and along grain boundaries when subjected to a range of heat treatment conditions. In this study, three different characterization methods were used to characterize these nanoscale precipitates: conventional scanning transmission electron microscopy (STEM); laboratory-based small-angle X-ray scattering (SAXS); and a new software analysis tool developed by Thermo Fisher Scientific: automated particle workflow (APW). Each method was used to determine average precipitate size and volume fraction of precipitation in AA7050-T7451 specimens with variable post-T7 heat treatment procedures. STEM techniques measured the average particle size as ranging from 7.6 to 17.6 nm, compared to 6.3–10.7 nm for SAXS, and 7.4–10.8 nm for APW. Volume fraction determinations varied from 0.23 to 16 %, depending on method, and were the most difficult to quantify. Significant outcomes of the current study are that SAXS and APW are the most accurate methods for determining average particle size and that future work is needed to effectively analyze precipitate volume fraction.

Impact of the combined assimilation of GPM/IMGER precipitation and Himawari-8/AHI water vapor radiance on snowfall forecasts using WRF model and 4Dvar system

Impact of the combined assimilation of GPM/IMGER precipitation and Himawari-8/AHI water vapor radiance on snowfall forecasts using WRF model and 4Dvar system

X-Band Radar and Surface-Based Observations of Cold-Season Precipitation in Western Colorado’s Complex Terrain

Abstract Hydrologic processes associated with intermountain cold-season precipitation in the Upper Colorado River basin have important impacts on avalanche forecasting and water resource management. However, traditional weather radar networks struggle with observations in this complex terrain. Data collected during the Study of Precipitation, the Lower Atmosphere, and the Surface for Hydrometeorology (SPLASH) and its sister campaign, Surface Atmosphere Integrated Field Laboratory (SAIL) in the East River watershed of western Colorado, are used to examine a multistorm period from 23 December 2021 to 1 January 2022 that contributed 35% of the total winter precipitation in this watershed. Dual-polarization X-band radar and disdrometer measurements show ∼30-mm differences in precipitation amount at two sites in proximity over four distinct storm events within the period. Wind patterns, synoptic forcings, microphysical characteristics of precipitation, and surface meteorology are analyzed to explain the observed spatial variability of cold-season precipitation in complex mountainous terrain. Analysis shows that differences over time within this event are mainly accounted for by synoptic forcings, such as frontal passages; differences between sites are accounted for by the impact of variations in local wind patterns on precipitation microphysics. Patterns of surface precipitation intensity are compared and found to be correlated with X-band radar signatures; a relationship between a strong dendritic growth stage and intense low-density surface precipitation is reinforced by this study. This relationship demonstrates the importance of particle growth mechanisms on surface snowfall patterns in high-altitude complex terrain, underscoring the importance of realistic microphysical parameterizations. Significance Statement The amount and density of snowpack from western Colorado winter storms have significant impacts on water resources in the Upper Colorado River basin. Snowpack characteristics are affected by small-scale differences in how snow forms in the atmosphere. These differences are hard to study in the complex terrain of the Rockies, but data from the SPLASH and SAIL field campaigns allows us to investigate how snow crystal formation and mountain-driven wind patterns affect snow near the surface. Our study finds that snow crystal growth varies over small space and time scales and is likely controlled by the terrain beneath a given location and resultant local wind patterns. These results imply that predicting snowpack in the Rockies requires properly representing local wind patterns and crystal growth processes in models.

Evolution mechanism of Ti(C,N)-based cermet microstructure under microwave sintering

Experimental studies of microwave-sintered cermets were carried out at different sintering temperatures and holding times to investigate their microstructure evolution mechanism. Results of the study show that: (1) As sintering temperature increases, main microstructure evolution mechanisms of cermets are as follows: metal-phase melting, hard-phase skeleton filling of large pores in hard-phase skeletons, secondary rearrangement of the liquid phase (the liquid phase gradually fills the space between grains), and cooling down (precipitation–crystallization–reattachment); (2) As holding time increases, main microstructure evolution mechanisms of cermets are as follows: complete filling of large pores in the hard-phase skeleton, secondary rearrangement of the liquid phase, intense dissolution precipitation enhancing the formation of core-rim phase, and secondary homogeneous arrangement of the liquid phase. The special electromagnetic effects of microwave-sintered cermets and their influence on the sintering process were analyzed. It was found that both tip-discharge effect and hot-spot effect occurring during the microwave sintering process are conducive to the sintering process. The formation process of core-rim phase of cermets was also studied. Results show that: (1) Cermets form black core–white rim–grey rim structure via dissolution–precipitation and precipitation–crystallization phenomena; (2) Cermets form white core–grey rim structure through agglomeration of small particles, dissolution–precipitation, and precipitation–crystallization phenomena.

Ionospheric plasma irregularities over Dronning Maud Land in Antarctica and associated space weather effects

Ionospheric plasma irregularities and associated space weather effects over Dronning Maud Land in Antarctica are studied with a multi-instrument approach. It is demonstrated during a substorm event that auroral particle precipitation associated with the edges of auroral arcs can lead to irregularities in the ionospheric plasma density that can have significant impact on trans-ionospheric radio waves. Both refractive and diffractive effects are observed on signals from the GNSS satellites, where the latter are identified by the ionospheric free linear combination approach and amplitude scintillation. Thus, intense auroral particle precipitation can lead to plasma irregularities at scales from several kilometers down to and below the Fresnel radius, and they can result in space weather effects which can lead to losing the integrity of the GNSS signals.

Faecal contamination determines bacterial assemblages over natural environmental parameters within intermittently opened and closed lagoons (ICOLLs) during high rainfall

Intermittently closed and opened lakes and lagoons (ICOLLs) provide important ecosystem services, including food provision and nutrient cycling. These ecosystems generally experience low watershed outflow, resulting in substantial fluctuations in physicochemical parameters that are often compounded by anthropogenic contamination, however the patterns in microbiology within these environments remains uncharacterised. Therefore, we aimed to determine how seasonal heterogeneity in the physicochemical parameters, in comparison to faecal contamination, alter the dynamics of bacterial communities inhabiting ICOLLs on the eastern Australian coast. To address these aims, we sampled four ICOLLs on a monthly basis for one year, using 16S rRNA gene amplicon sequencing to monitor patterns in bacterial diversity and qPCR-based methods to measure faecal contamination from humans (sewage), dogs, and birds. Additionally, we used qPCR to monitor patterns of a suite of antibiotic resistance genes (ARGs) including sulI, tetA, qnrS, dfrA1, and vanB. Differences in bacterial community composition were often associated with temporal shifts in salinity, temperature, pH, DO, and fDOM, but following periods of high rainfall, bacterial assemblages in two of four ICOLLs changed in direct response to sewage inputs. Within these ICOLLs, indicator taxa for stormwater identified using the 16S rRNA amplicon sequencing data, as well as markers for sewage and dog faeces, and levels of the antibiotic resistance genes (ARGs) sulI, tetA, and dfrA1 were significantly more abundant after rainfall. Notably many of the stormwater indicator taxa were potential human pathogens including Arcobacter and Aeromonas hydrophilia, which also displayed significant correlations, albeit weak to moderate, with levels of the ARGs sulI, tetA, and dfrA1. This broad-scale shift in the nature of the bacterial community following rainfall will likely lead to a substantial, and perhaps detrimental, divergence in the ecosystem services provided by the bacterial assemblages within these ICOLLs. We conclude that following rainfall events, sewage was a principal driver of shifts in the microbiology of ICOLLs exposed to stormwater, while natural seasonal shifts in the physicochemical parameters controlled bacterial communities at other times. Increased occurrence of intense precipitation events is predicted as a ramification of climate change, which will lead to increased impacts of stormwater and sewage contamination on important ICOLL ecosystems in the future.

Multi-scale assessment of high-resolution reanalysis precipitation fields over Italy

This study focuses on the validation of high-resolution regional reanalyses to understand their effectiveness in reproducing precipitation patterns over Italy, a climate change hotspot characterized by coastal sea-land interaction and complex orography. Nine reanalysis products were evaluated, with the ECMWF global reanalysis ERA5 serving as a benchmark. These included both European (COSMO-REA6, CERRA) and Italy-specific (BOLAM, MERIDA, MERIDA-HRES, MOLOCH, SPHERA, VHR-REA_IT) datasets, using different models and parametrizations. The inter-comparison involved determining the effective resolution of daily precipitation fields using wavelet techniques and assessing intense precipitation statistics through frequency distributions. In-situ observations and observational gridded datasets were used to independently validate reanalysis precipitation fields. The capability of reanalyses to depict daily precipitation patterns was assessed, highlighting a maximum radius of precipitation misplacement of about 15 km, with notably lower skills during summer. An overall overestimation of precipitation was identified in the reanalysis climatological fields over the Po Valley and the Alps, whereas multiple products showed an underestimation of precipitations across the North-West coast, the Apennines, and Southern Italy. Finally, a comparison with a time-consistent observational dataset (UniMi/ISAC-CNR) revealed a non-stable deviation from observations in the annual precipitation cumulate of the reanalysis products analyzed. This should be taken into account when interpreting precipitation trends over Italy.

Effect of aging temperature on the redrawn cup wall of a novel Cu-0.5Cr-0.05Zr-0.05Ti (wt.%) alloy sheet: Analyses on microstructure evolution, mechanical properties and strengthening mechanism

A solution-treated Cu-0.5Cr-0.05Zr-0.05Ti (wt.%) alloy was drawn into a large-depth cup implementing a two-stage deformation process in the present study, firstly using a ∅50 mm cylindrical punch and subsequently redrawn by a ∅34 mm punch. The redrawn cup wall was subjected to aging heat treatment up to 400 °C, 500 °C, and 600 °C for 2 h followed by water quenching to understand the microstructural evolution and its correlation with mechanical properties. These aging temperatures were adopted to simulate a similar environmental condition in which the inner liner of the thrust chamber of cryogenic and semi-cryogenic engines was exposed during satellite launching. It was identified that the above aging temperatures influenced the grain characteristics, recrystallization, and annealing twin formation significantly. The redrawn cup wall possessed semi-coherent bcc spherical Cr-rich precipitates with an average size of 1.8 ± 0.1 nm, which progressively increased to 5.5 ± 0.3 nm at 600 °C, while the precipitate volume fraction increased to a maximum of 1.2% at 500 °C. The precipitation mostly influenced the strength, while the recrystallization and twin formation governed the ductility during the aging. After an initial decrement at 400 °C, the yield strength of the aged specimen was increased to a maximum of 193 MPa with a concurrent increase in ductility to 24% upon the optimal aging at 500 °C. However, a higher increment in the strength than the ductility indicated the dominance of the precipitation. Further increase in the temperature to 600 °C reduced the strength while considerably enhancing the ductility. This was attributed to the highest recrystallization and twin fraction, as well as precipitate coarsening with reduced volume fraction. Moreover, precipitation strengthening prevailed in the aged specimens, unlike dislocation strengthening in the redrawn condition. The contribution from the former was maximum at 500 °C with a 52% share of the total estimated strength, whereas it was only 31% in the redrawn specimen.

Increasing contribution of the atmospheric vertical motion to precipitation in a warming climate

Global warming already influences precipitation, with more intense precipitation in many locations. Although the ‘wet-get-wetter, dry-get-drier’ tendency in mean precipitation holds in many locations, the situations for precipitation extremes are more complex, due to changes in dynamic and thermodynamic influences on atmospheric moisture distributions. Here, we build a dynamically interactive atmospheric moisture model for the present (2006–2025) and the future climate (2081–2100), using outputs from coupled ocean-atmosphere general circulation models. We find that the dynamic process of vertical advection of moisture dominates the same-day precipitation, while the smaller impact of the thermodynamic process provides available moisture for several days. As climate warms, we find that the dynamical-induced precipitation more completely exhausts the vertically-integrated moisture and the distribution of the dynamic process’s impact on precipitation exhibits a greater spread in the warmer future. The dynamical process is primarily responsible for more extreme heavy precipitation as climate warms, at all latitudes.

Terms for describing atmospheric deposition of substances on surfaces

Relevance. The need to assess the state of the environment based on the use of terminology for quantitative chemical characteristics of the underlying surface as a result of deposition of pollutants in the composition of wet and dry fallout from the atmosphere. Aim. This study can be a source of information about the terminology used to describe the state of the underlying surface during the deposition of substances from the atmosphere, with links to scientific and technical literature. Methods. Review of some scientific and technical literature and an attempt to select terms used to quantify the ecological state of the underlying surface, mainly snow, after the arrival of substances as part of dry and wet deposition from the atmosphere, depending on the sampling method. Results and conclusions. The author has carried out an analysis of the scientific and technical literature and defined the terms applied to a quantity that has the dimension mass/area*time for assessing the ecological state of the snow cover, such as specific reserve (surface density), deposition density, atmospheric deposition density, precipitation intensity pollutant, daily deposition of chemical elements, technogenic load, dust load, pollution load (element), mass load, gas-aerosol load, technogenic pressure module, input module, atmospheric fallout module, mass of the determined component received at unit area, flux obtained on the basis of sampling during snow chemical survey. An analysis of the scientific and technical literature was also carried out and the terms applied to a value with the same dimension mass/area*time were defined to assess the ecological state of the underlying surface during the deposition of substances from the atmosphere, such as "fallout density", "atmospheric fallout density", “pollutant fallout intensity”, “aggravating substance", "precipitation", "critical load", "flow" obtained based on sample collection using plates, cuvettes, collections.

Impact of precipitation change in the Yangtze River source area on groundwater from the perspective of ground-based and satellite-based observations

In the context of global climate change, the hydrological cycle of the Yangtze River source area has produced significant changes. It is of great practical value to study the influence of regional precipitation changes and precipitation events on regional water resources, especially groundwater. This study uses base flow segmentation and GRACE groundwater reserve calculation technology to examine precipitation’s spatial and temporal variation, especially extreme precipitation events, in the Yangtze River source area. The events analyzed were the extreme precipitation-runoff-base flow response from the Yangtze River source, the extreme precipitation-terrestrial water (surface water and groundwater) response, and the comparison of these events. The findings indicated that extremely strong precipitation, maximum precipitation for five consecutive days, days of moderate rain and above moderate rain intensity precipitation, the longest number of precipitation days, and other extreme precipitation indices had a significantly increasing trend and increased intensity of extreme precipitation events, the regional differences in precipitation trended less significantly. The base flow index gradually increased at a rate of 0.0014 yr-1, suggesting the overall increase of water resources and the contribution rate of groundwater to the runoff was an increased trend . There is a high correlation between the change of water resources in the source area and the change of precipitation, and the increased precipitation influenced an increase in groundwater and regional water resources. These findings inform current knowledge of precipitation-groundwater response mechanisms in alpine and arid regions such as the Qinghai-Tibet Plateau.

A high-resolution dataset for future compound hot-dry events under climate change.

Global climate change is leading to an increase in compound hot-dry events, significantly impacting human habitats. Analysing the causes and effects of these events requires precise data, yet most meteorological data focus on variables rather than extremes, which hinders relevant research. A daily compound hot-dry events (CHDEs) dataset was developed from 1980 to 2100 under various socioeconomic scenarios, using the latest NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP-CMIP6) dataset to address this. The dataset has a spatial resolution of 0.25 degrees (approximately 30 kilometres), including three indicators, namely D (the yearly sum of hot-dry extreme days), prI (the intensity of daily precipitation), and tasI (the intensity of daily temperature). To validate the accuracy of the dataset, we compared observational data from China (National Meteorological Information Center, NMIC), Europe (ERA5), and North America (ERA5). Results show close alignment with estimated values from the observational daily dataset, both temporally and spatially. The predictive interval (PI) pass rates for the CHDEs dataset exhibit notably high values. For a 90% PI, D has a pass rate exceeding 85%, whilst prI and tasI respectively show a pass rate above 70% and 95%. These results underscore its suitability for conducting global and regional studies about compound hot-dry events.

Diurnal variation of convective precipitation during the flood season in Fujian Province, China

Utilizing hourly observational data from automatic weather stations across Fujian Province from 2008 to 2020, this study defined and classified concepts and thresholds for convective precipitation, short-duration convective precipitation, long-duration convective precipitation, localized heavy precipitation, and widespread heavy precipitation. We explored the fundamental diurnal climatic characteristics of convective precipitation during the flood season in Fujian Province’s complex terrain. The results indicate the following. 1) Convective precipitation during the flood season exhibits distinct diurnal variation, with a significant spatial distribution along mountainous and coastal terrains. 2) The frequency of precipitation during the pre-flood season is higher and its intensity is lower than in the post-flood season. Due to differing primary weather systems influencing each period, resulting in substantial differences in the spatial distribution of precipitation frequency and intensity. 3) Both short-duration and localized precipitation show pronounced afternoon peaks in their diurnal patterns, predominantly occurring on windward slopes, highlighting mechanisms of afternoon moist convection and orographic lifting, whereas long-duration and widespread precipitation lack diurnal variation, reflecting the influence of large-scale circulation. These results will help forecasters better understand the unique precipitation characteristics of Fujian Province.