Extreme hydrometeorological events, including freezing rain and ice pellets, pose severe threats to countries across the Asian monsoon region. This was underscored by the unprecedented 2008 freezing disaster and recent extreme freezing events in 2025/2026 over southern China. While previous studies have highlighted the role of atmospheric rivers (ARs) in modifying precipitation types in other regions, research focusing on the populous Asian monsoon region, a hotspot of such high-impact events, remains insufficient. Here, based on an AR detection tool (ARDT) named ARIA-Asia v1.8 validated against seven ARDTs, we demonstrate that during 1961–2023, ARs account for over one-third of the liquid rain frequency in key coastal areas of East Asia (e.g., southern Japan, the Yangtze River Estuary), account for up to 50% of freezing rain events in eastern China, and account for 26%–44% of ice pellet events over the Yangtze River basin and southern China. Trends in AR activity have reduced liquid rain frequency across mid-latitude East Asia while significantly increasing AR-associated solid and mixed-phase precipitation in southern China, particularly during the cold season. Using five machine-learning algorithms, feature importance analyses reveal that trends in AR frequency contribute approximately 53% of the total feature importance for AR-associated liquid rain, whereas trends in solid and mixed-phase precipitation are jointly governed by thermodynamic (e.g., sensible/latent heat fluxes) and microphysical (e.g., cloud ice, snow water content) processes. Our findings demonstrate that ARs are key weather systems reshaping the regional distribution of hydrometeors and high-impact precipitation types in Asia. These findings provide critical insights for improving the prediction of hydrometeor-related disasters and informing mitigation strategies under climate change.

The unprecedented extreme precipitation event occurred in Henan Province, the third most populated province in China, resulting in tremendous damage, casualties, and widespread public concern. This study investigates the atmospheric river (AR) environments and the related precipitation during the Henan extreme precipitation event using an AR detection algorithm. The diagnostic field generated by the algorithm indicates that an enhanced vertically integrated water vapor transport was identified as an AR developing over the target region, with its upstream detected over Henan lasting about 30-h. Analyses of moisture and dynamic conditions indicate that the AR formed in warm-core structures, characterized by a pre-frontal low-level jet of an upper-level trough embedded within the plume. The large-scale steering flows, resulting from the interaction between the binary tropical cyclones (TCs) and the western Pacific subtropical high, transported the upstream moisture originating from the TCs Infa and Cempaka to the AR plume over Henan. During the event, the extreme precipitation intensity in Henan was directly linked to the degree of AR influence locally. The dominant forcing mechanism for the AR-related precipitation was primarily attributed to the dynamical forcing ascent as the AR impinging on the mountainous topography near Henan, which was characterized by the saturated upslope flow within the water vapor transport associated with the AR. This paper highlights the role of AR and its interaction with TCs in the unprecedented extreme precipitation event, which emphasizes the importance of promoting local knowledge of AR-related hydrometeorological environments and their destructive impacts in the mid-latitudes of East Asia.

In the summer of 2022, a record-breaking heatwave and drought event occurred in the Yangtze River (YR) Basin of China, causing great damage to the society and ecosystem. However, the role of land-atmosphere (LA) interactions in driving and reinforcing this event has not been fully studied. In this study, using air temperature, soil moisture (SM), surface sensible heat fluxes, surface latent heat fluxes and radiation fluxes data from ERA5, we analyze the process of this event and reveal the contribution of the LA feedbacks. The results indicate that during the 2022 YR Basin heatwave and drought event, the regional average maximum air temperature and SM reached unprecedented levels of 2.7 standard deviations (SDs) and -3.5 SDs, respectively, compared to the climatology from 1980 to 2021. In August 2022, SM rapidly declined, pushing the region into a rare "dry" state. The dry soil increased the sensitivity of daily maximum air temperature to SM, intensifying the occurrence of heatwaves in the area. Simultaneously, increased downward solar radiation reached surface and most of that converted to sensible heat fluxes due to low soil moisture limitations leading to elevated air temperatures. While similar events have been reported multiple times in regions like Europe and western North America, their occurrence in the "moist" region of the YR Basin of China is exceptionally rare, which suggests an increasing likelihood of such extreme events in this region. Land-atmosphere interactions play an increasingly crucial role in exacerbating extreme conditions, and therefore, more studies such as this are needed for improving predictability of extreme events on a sub-seasonal time scale.

Widespread spring vegetation greening (inferred by LAI) in the Northern Hemisphere leads to additional summer soil moisture (SM) deficits through increasing transpiration. Meanwhile, vapor pressure deficit (VPD) has also been rising, which can increase atmospheric evaporative demand. However, the extent and magnitude of influence of these two factors on SM changes have not been elucidated. Here, based on the state-of-the-art reanalysis and remote sensing data, we use three statistical methods to quantify the contributions of spring LAI and summer VPD to summer SM deficit. The results show that summer VPD contributes more to SM change than spring LAI in the southwestern and northern regions of North America, northeastern Europe, and central and southeastern Asia, covering 13.4% of the vegetated areas despite of the certain influence of spring vegetation greening on summer soil drying. The results are of great significance for climate change adaptation and the enhancement of surface water management.

Abstract The recent and unprecedented flood events in the populated regions of Asia have raised concerns about how atmospheric rivers (ARs), an important agent of extreme precipitation over the region, will change under global warming. An ensemble of high-resolution general circulation models projects that ARs and their associated precipitation penetrate Asia further in the next three decades. ARs are thermodynamically enhanced at mid-latitudes and dynamically inhibited at low latitudes, which induce more frequent ARs and their associated extreme precipitation across the subtropics and midlatitudes of South Asia and East Asia. In these regions, the population exposure to AR-associated extreme precipitation is projected to increase significantly and be amplified by the increased population density, particularly in the urban areas of northern China, northern India and Bangladesh (by 24–59%). Hence, promoting preparedness for adapting to changes in AR-related hydrological environments is crucial for these regions in the next few decades.

Extreme precipitation events are linked to severe economic losses and casualties in China every year; hence, exploring the potential mitigation strategies to minimize these events and their changes in frequency and intensity under global warming is of importance, particularly for the populous subregions. In addition to global warming scenarios, this study examines the effects of the potential deployment of stratospheric aerosol injection (SAI) on hydrological extremes in China based on the SAI simulations (G6sulfur) of the Geoengineering Model Intercomparison Project (GeoMIP) by the UK Earth System Model (UKESM1) simulations. G6sulfur is compared with simulations of the future climate under two different emission scenarios (SSP5-8.5 and SSP2-4.5) and a reduction in the solar constant (G6solar) to understand the effect of SAI on extreme precipitation patterns. The results show that under global warming scenarios, precipitation and extreme wet climate events during 2071–2100 are projected to increase relative to the control period (1981–2010) across all the subregions in China. Extreme drought events show a projected increase in southern China. The G6sulfur and G6solar experiments show statistically similar results to those under SSP2-4.5 in extreme precipitation intensities of China in UKESM1. These results are encouraging. The efficacy of SAI in decreasing extreme precipitation events and consecutive wet days is more pronounced than that of G6solar when compared to SSP2-4.5. While both G6sulfur and G6solar show drying at high-latitude regions, which is consistent with our understanding of the spin-down of the hydrological cycle under SRM. Given the limitations of the current model and the small ensemble size, and considering that the hydrological effects are less beneficial than those indicated for temperature, it is recommended that further, more comprehensive research be performed, including using multiple models, to better understand these impacts.

The regional climate over China has changed pronouncedly since the mid-20th, posing substantial risks and uncertainties to local crop production. The maize production has demonstrated considerable sensitivity to such changes. Observations in recent years witnessed that the use of fertilizer has been a crucial contributor to the increase in yields of global staple crops including maize. Thus, adjusting fertilizer use is a potential measure to offset the negative impacts of climate change on staple crops, while quantifying the pros and cons of such a measure for maize production has not been sufficiently performed. Based on multiple sources of observational records and statistical yield simulations, this study assesses the impacts of historical trends of regional climate and fertilizer use on maize yield over the main cultivation regions in China for the period 1981 to 2020. The results show that 1 °C of warming has resulted in pronounced changes in the general maize yield (−5.5 ± 0.5 %–21.1 ± 1.1 %, mean ± error standard). In comparison, a 10 % increase in fertilizer use has resulted in boosted yield by 2.4 ± 0.2 %–4.3 ± 0.2 %. For the mitigation effects of fertilizer, a 10 % increase in fertilizer use can offset 2–3 % of yield reductions associated with the changes in both temperature and precipitation. During the climate change period, the contribution of temperature and precipitation trends shifted from yield loss (by −8.1 ± 1.5 %) to yield gain (by 5.1 ± 2 %) from north to south, while more fertilizer uses contributed to maize yield gain across the maize belt by 26.4 ± 1.1 %. This quantified information indicates the crucial role of fertilizer use in alleviating the hazardous impacts of regional climate changes on maize production in China, which delivered a key message for optimizing strategies for climate change adaptation in maize production zones across China.

Soil moisture (SM) directly controls the land surface energy partition which plays an important role in the formation of extreme weather events. However, its dependence on specific climatic conditions is not thoroughly understood due to the complexity of soil moisture effects. Here, we examine the relationship between SM and surface energy partitioning under different climate conditions, and identify the influence paradigms of soil moisture on surface energy partition. We find that temperature changes can explicitly determine the impact paradigm of different physical processes, i.e. evapotranspiration, soil freezing and thawing, and such influence paradigms are also affected by atmospheric aridity (VPD). Globally, there are five paradigms that effects on surface energy partitioning, including the warm-wet paradigm (WW), transitional paradigm (TP), warm -dry paradigm (WD), cool-wet paradigm (CW) and cold paradigm (CP). Since 1981, the global area proportion for TP is observed to increase pronouncedly. We also find that the critical SM threshold exhibits regional variations and the global average is 0.45 m3/m3. The identified paradigms and their long-term change trends provide new insights into the global intensification of land -atmosphere interaction, which has important implications for global warming and the formation of heatwaves.

Atmospheric rivers (ARs) are closely associated with historical extreme precipitation events over East Asia. The projected increase in such weather systems under global warming has been extensively discussed in previous studies, while the role of stratospheric aerosol, particularly for the implementation of stratospheric aerosol intervention (SAI), in such a change remains unknown. Based on an ensemble of the UK Earth System Model (UKESM1) simulations, here we investigate changes in the frequency of ARs and their associated mean and extreme precipitation under a range of climate forcing, including greenhouse gas emission scenarios of high (SSP5–8.5) and medium (SSP2–4.5) levels, the deployment of SAI geoengineering (G6sulfur), and solar dimming (G6solar). The result indicates a significant increase in AR frequency and AR-related precipitation over most of East Asia in a warmer climate, and the most pronounced changes are observed in southern China. Comparing G6solar and both the Shared Socioeconomic Pathway (SSP) scenarios, the G6sulfur simulations indicate that SAI is effective at partly ameliorating the increases in AR activity over the subtropical region; however, it may result in more pronounced increases in ARs and associated precipitation over the upper-midlatitude regions, particularly northeastern China. Such a response is associated with the further weakening of the subtropical westerly jet stream under SAI that favours the upper-midlatitude AR activity. This is driven by the decreased meridional gradient of thermal expansion in the mid–high troposphere associated with aerosol cooling across the tropical region, though SAI effectively ameliorates the widespread increase in thermal expansion under climate warming. Such a side effect of SAI over the populated region implies that caution must be taken when considering geoengineering approaches to mitigating hydrological risk under climate change.

The vast majority of reductions in aerosol emissions are projected to take place in the near future; however, associated impacts on the large-scale circulation over the populated Asian monsoon region remain uncertain. Using the state-of-the-art UK Earth System Model version 1 (UKESM1), this study examines the response of the South Asian summer monsoon and East Asian summer monsoon (SASM and EASM, respectively) to idealized reductions in anthropogenic emissions of carbonaceous aerosols and SO2. The analysis focuses on changes in the monsoon temporal extent and intensity of precipitation following decreases in either scattering (SCT) or absorbing (ABS) aerosols or decreases in both. For SCT, the combination of the early transition of land-sea thermal contrast and sea level pressure gradient during the pre-monsoon season, together with the late transition in the post-monsoon season associated with the tropospheric warming, advances the monsoon onset but delays its withdrawal, which leads to an extension of the summer rainy season across South Asia and East Asia. The northward shift of the upper-tropospheric Asian jet forced by the SCT reduction causes the anomalous convergence of tropospheric moisture and low-level ascent over northern India and eastern China. The intensification of the South Asian high (SAH) due to the warming over land also contributes to the dynamic instability over Asia. These changes enhance the rainy season of these regions in boreal summer. Reductions in absorbing aerosol act in the opposite sense, making the Asia's rainy season shorter and weaker due to the opposite impacts on land-sea contrast, Asian jet displacement and SAH intensity. With reductions in both SCT and ABS aerosol together the monsoon systems intensify, as the overall impact is dominated by aerosol scattering effects and results in the strengthening of monsoon precipitation and 850 hPa circulation. Although aerosol scattering and absorption play quite different roles in the radiation budget, their effects on the monsoon precipitation seem to add almost linearly. Specifically, the patterns of monsoon-related large-scale responses from reducing both SCT and ABS together are similar to the linear summation of separate effect of reducing SCT or ABS alone; this is despite the inherent nonlinearity of the atmospheric systems. The opposing adjustments of Asian rainy season forced by the ABS and SCT aerosol emission reductions suggest that emission controls that target factors like emissions of black carbon that warm the climate would have a different response to those that target overall aerosol emissions.

Projected near-future changes in mean and extreme precipitation by the end of the mid-21st century over China are investigated using the latest CMIP6 HighResMIP simulations grouped by different categories of horizontal and vertical resolutions. Evaluation of the historical simulations demonstrates improvements in the realism of the simulated precipitation over the different sub-regions with increased model resolutions. More apparent improvements are displayed by models with increased vertical resolution than those with increased horizontal resolutions. The near-future scenario of SSP5–8.5 suggests general increases in mean and extreme precipitation across Northwest and East-Northeast China. Also, models with coarser horizontal resolutions project an intensified precipitation seasonality over China. Models at relatively high vertical resolutions project decreased precipitation and enhanced droughts over Southwest China, while these are less apparent in models with relatively coarse vertical resolutions. All the simulations project a northward shift of summer and winter monsoon flows in East Asia. Meanwhile, a weaker summer monsoon across the tropics with a weakening of the monsoon trough over the South China Sea are projected. This indicates a less favorable environment for precipitation across the southern sub-regions. The complicated responses of precipitation to these environmental mechanisms are partly linked to the presented resolution-dependent uncertainties. Such uncertainties should be recognized and treated with caution in understanding the near-future hydrological changes in China.

Borneo Vortices (BVs) are weather systems that are responsible for devastating hydro-climatic extremes and significant losses of life and property in Southeast Asia. The typical resolution of most current climate models is insufficient to resolve these high-impact, synoptic-scale weather systems. Here, an ensemble of high-resolution models projects that future BVs may become less frequent and more stationary, driven by the weakening of the Northeast monsoon flow and associated cold surges across North Borneo. However, substantial increases in both the intensity and the total amount of precipitation from BVs are projected. Such changes are driven by the more humid and convectively unstable lower troposphere. As a result, the contribution of BVs to the accumulation of both total precipitation and extreme precipitation is projected to increase considerably in the vicinity of the southern South China Sea, making individual BVs more threatening to the adjacent coastal regions.

The dynamic characteristics of atmospheric rivers (ARs) have been researched over the western North Pacific and East Asia due to their close linkage to disastrous precipitation extremes, while very little attention has been paid to the AR features from the western Pacific to Southeast Asia. This study aims to quantify the climatology, long-term trends and variability of different AR properties from the western Pacific to Southeast Asia using an objective identification algorithm, the ERA5 reanalysis dataset and the APHRODITE precipitation dataset for the period 1951-2015. The results indicate a belt of frequent AR activities from the western Pacific to the Andaman Sea during the boreal autumn-winter season. The long-term trend analyses show a significantly increasing trend in AR frequency and an eastward shift of AR plumes. These dynamic changes contribute to the increasing trend of extreme precipitation amounts in the coastal areas surrounding the South China Sea. The intraseasonal variability of the AR associated with the Madden-Julian oscillation (MJO) shows a pronounced enhancement of AR activity in the MJO phase-2 to phase-3 due to the steeper gradient of low-level geopotential height between the Northwestern Pacific and the tropical Indian Ocean. The modulation is partly explained by the enhanced MJO convection and the adiabatic heating in the vicinity of the trough of the 200-500 hPa geopotential thickness of the region. This study shows that ARs are important mechanisms behind the climatology, trends and variability of the regional precipitation in Southeast Asia. This study implies that more attention is required toward the dynamics of these tropical weather systems, particularly for their interactions with other synoptic processes and their response to future climate warming.

Atmospheric rivers (ARs) play an important role in the climate of East Asia due to their close linkage to precipitation extremes. In this study, long-term trends in ARs over East Asia for the period 1951–2015 are investigated using long-term records of historical climate, including the ERA5 climate reanalysis and the APHRODITE precipitation dataset. These datasets are produced at a relatively high spatial resolution of 0.25° × 0.25°, which allows for evaluation of the long-term trends in the fine-scale characteristics of ARs. The results indicate a significant decreasing trend in ARs and the associated precipitation over the north of East Asia. These dynamical changes dominate the decreasing trend of total summer precipitation amounts in parts of northern China. The decreasing trend in ARs over the north is principally related to the intensification and southward displacement of the southwesterly monsoon flow in boreal summer. In contrast, increasing AR activity and the associated precipitation and heavy rain events over the south of East Asia are observed. These changes are associated with a warmer and more humid environment along AR axes, as well as the southward shift of ARs driven by the dynamical responses of the large-scale environments in the context of climate warming. These responses include the intensification of the upper-level westerly jet accompanied with the strengthening of the South Asian Anticyclone during summer season. Moreover, in contrast to the general decreasing trends in boreal summer, AR activity during boreal winter-spring exhibits significant increasing trends, implying a potential weakening of the seasonality of ARs. This study shows that ARs are important synoptic mechanisms within observed precipitation trends over East Asia, such that understanding their response to a warming climate is a prerequisite to characterizing the nature of future precipitation changes in this region.

This study evaluates the performance of the Met Office Hadley Centre Global Environment Model 3-Global Coupled version 3.1 (HadGEM3-GC3.1) in simulating the climatology of atmospheric rivers (ARs) over East Asia during the period 1951-2014. Compared to a high-resolution climate reanalysis dataset and three different precipitation observation datasets, better performances in simulating the characteristics of ARs, including the frequency of occurrences, intensity of moisture transport, meridional heat transport and contributions to precipitation, are demonstrated by the simulation at the N512 (0.35 degrees x 0.23 degrees, similar to 25-km) horizontal resolution compared to those at the N96 (1.875 degrees x 1.25 degrees, similar to 135-km) and N216 (0.83 degrees x 0.56 degrees, similar to 65-km) resolutions. Also, the N512 experiment is more capable of representing the significant increase in AR frequency for the years with preceding El Nino events. However, the N512 experiment still presents an underestimation of AR frequency in different seasons. In contrast to the N96 and N216 simulations, it overestimates the AR-associated extreme precipitation amount over most of the study region, which is partly explained by the more precipitation-favorable thermodynamic conditions along the simulated AR axes. Overall, a sufficiently high horizontal resolution is crucial for the GCM to realistically represent the observed characteristics of ARs over East Asia and to robustly project their potential changes in a warming climate, although the systematic errors still affect the realism of the simulated ARs.

Changes in the monsoon season rainfall over Peninsular Malaysia by the mid-21st century are examined using multi-model ensemble data from the CMIP6 HighResMIP experiments. We examine simulations of the present and future climate simulations run under a high emission scenario of greenhouse gases from the Shared Socioeconomic Pathways (SSP5-8.5). The combined effects of horizontal and vertical resolutions on the projected changes in monsoon rainfall and associated environmental fields are investigated by comparing the ensemble mean of the projected changes utilizing appropriate multi-model groupings. The results indicate a projected decrease (by up to 11% near Mersing of eastern Johor, for the period 2031–2050 relative to 1981–2000) in monsoon precipitation along the southeastern coast of Peninsular Malaysia during the northeast monsoon season associated with the projected weakening of the monsoon flow during boreal winter. For the northwestern regions (e.g. Perak) often affected by severe floods, a significant increase in precipitation (by up to 33%) is projected during the southwest monsoon season, partly driven by the projected strengthening of the cross-equatorial flow and the weakened low-level anti-cyclonic shear of winds in boreal summer. However, the magnitudes and signal-to-noise ratios of the projected changes vary considerably with respect to different horizontal and vertical resolutions. Firstly, models with relatively high horizontal and vertical resolutions project a more significant decrease in precipitation during the northeast monsoon season. Secondly, for the southwest monsoon season, models with relatively high horizontal resolutions project larger magnitudes of increases in precipitation over the northern region, while smaller increases are found in simulations with relatively high vertical resolutions. Generally, reduced ensemble spread and increased signal-to-noise ratios are found in simulations at higher horizontal and vertical resolutions, suggesting increased confidence in model projections with increased model resolution.

The west coast of Canada is strongly affected by the extreme precipitation events triggered by frequent atmospheric river (AR) activities over the eastern North Pacific. Across the region, assessing the probable maximum precipitation (PMP), can provide valuable information for resilience building of the coastal communities that are vulnerable to hydrological risks. In this study, a 3-km convection-permitting regional climate model is used to physically estimate the PMP in Vancouver. This technique maximizes the effect of AR-related water vapor transport by spatially adjusting the lateral boundary conditions (LBCs) of the model simulations for the selected AR-related extreme precipitation events. The PMP in Vancouver is identified among the simulations driven by the spatially adjusted LBCs that are corresponding with the AR-induced “worst-case scenario,” i.e., landfalling ARs hit Vancouver with optimal landfalling location and transport direction. Results suggest that the PMP in Vancouver, in terms of the maxima of the regionally averaged 72-h total precipitation for the historical extreme precipitation events, is up to 790 mm, which is 130% greater than the historical peak precipitation for the period 1980∼2017. On average, all the PMP simulations shows an overall increase by 81% in precipitation by relative to historical simulations. In addition, the PMP simulations suggested an overall decrease in snowfall by 12% due to the warmer near-surface air temperature; however, a pronounced increase in freezing rain is seen. The precipitation increase for the estimated PMP relative to the historical extreme precipitation is closely associated with the increased atmospheric moisture transport and the changes in the atmospheric dynamic factors when the AR effects are maximized. These include the enhanced low-tropospheric ascent and moisture transport convergence, which can induce stronger depletion of atmospheric moistures as indicated by the increased precipitation efficiency.

This study introduces a hydro-climatic extremes assessment framework that combines the latest climate simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) HighResMIP with the Soil and Water Assessment (SWAT) model, and examines the influence of the different climate model resolutions. Sixty-six hydrological and environmental flow indicators from the Indicators of Hydrologic Alteration (IHA) were computed to assess future extreme flows in the Kelantan River Basin (KRB), Malaysia, which is particularly vulnerable to flooding. Results show that the annual precipitation, streamflow, maximum and minimum temperatures are projected to increase by 6.9%, 9.9%, 0.8 °C and 0.9 °C, respectively, by the 2021–2050 period relative to the 1985–2014 baseline. Monthly precipitation and streamflow are projected to increase especially for the Southwest Monsoon (June–September) and the early phase of the Northeast Monsoon (December) periods. The magnitudes of the 1-, 3-, 7-, 30- and 90-day minima flows are projected to increase by 7.2% to 8.2% and the maxima flows by 10.4% to 28.4%, respectively. Lastly, changes in future hydro-climatic extremes are frequently quite different between the high-resolution and low-resolution models, e.g., the high-resolution models projected an increase of 11.8% in mean monthly flow in November-December-January compared to 3.2% for the low-resolution models.

This study investigates the ability of 20 model simulations which contributed to the CMIP6 HighResMIP to simulate precipitation in different monsoon seasons and extreme precipitation events over Peninsular Malaysia. The model experiments utilize common forcing but are run with different horizontal and vertical resolutions. The impact of resolution on the models’ abilities to simulate precipitation and associated environmental fields is assessed by comparing multi-model ensembles at different resolutions with three observed precipitation datasets and four climate reanalyses. Model simulations with relatively high horizontal and vertical resolution exhibit better performance in simulating the annual cycle of precipitation and extreme precipitation over Peninsular Malaysia and the coastal regions. Improvements associated with the increase in horizontal and vertical resolutions are also found in the statistical relationship between precipitation and monsoon intensity in different seasons. However, the increase in vertical resolution can lead to a reduction of annual mean precipitation compared to that from the models with low vertical resolutions, associated with an overestimation of moisture divergence and underestimation of lower-tropospheric vertical ascent in the different monsoon seasons. This limits any improvement in the simulation of precipitation in the high vertical resolution experiments, particularly for the Southwest monsoon season.

Borneo vortices (BVs) are intense precipitating winter storms that develop over the equatorial South China Sea and strongly affect the weather and climate over the western Maritime Continent because of their association with deep convection and heavy rainfall. In this study, the ability of the Hadley Centre Global Environment Model 3–Global Coupled, version 3.1 (HadGEM3-GC3.1), global climate model to simulate the climatology of BVs at different horizontal resolutions is examined using an objective feature-tracking algorithm. The HadGEM3-GC3.1 at the N512 (25 km) horizontal resolution simulates BVs with well-represented characteristics, including their frequency, spatial distribution, and lower-tropospheric structures when compared with BVs identified in a climate reanalysis, whereas the BVs in the N96 (~135 km) and N216 (~65 km) simulations are much weaker and less frequent. Also, the N512 simulation better captures the contribution of BVs to the winter precipitation in Borneo and the Malay Peninsula when compared with precipitation from a reanalysis data and from observations, whereas the N96 and N216 simulations underestimate this contribution because of the overly weak low-level convergence of the simulated BVs. The N512 simulation also exhibits an improved ability to reproduce the modulation of BV activity by the occurrence of northeasterly cold surges and active phases of the Madden–Julian oscillation in the region, including increased BV track densities, intensities, and lifetimes. A sufficiently high model resolution is thus found to be important to realistically simulate the present-climate precipitation extremes associated with BVs and to study their possible changes in a warmer climate.