Search Results (372)

Hydrological drought, expressed as anomalously low water availability in rivers, aquifers, and reservoirs, poses a growing threat to water security in densely populated regions such as the Metropolitan Region of Sao Paulo (MRSP), Brazil. Characterizing how drought propagates into large-scale terrestrial water storage (TWS) deficits, and how these deficits translate into measurable surface deformation, remains challenging in complex, human-managed hydrological systems such as the Cantareira Water Supply System. This study conducts an integrated, multi-sensor geodetic assessment of drought-related hydrological dynamics in the Cantareira System, combining vertical/LOS ground displacement derived from continuous GPS observations and Sentinel-1 InSAR time series with terrestrial water storage anomalies (TWSAs) from GRACE/GRACE-FO, groundwater level records, reservoir storage, and meteorological drought indicators. Cross-correlation analysis reveals a strong and statistically significant coupling between GRACE-TWSA and GPS-derived vertical displacement, with correlation coefficients of $r=-0.8$ (Upper Tietê basin) and $r=-0.6$ (PCJ basin), consistent with an elastic crustal response to hydrological loading. Reservoir storage in the PCJ basin is similarly correlated with regional TWSA (up to $r=0.7$ for the Jaguari–Jacareí reservoir), reinforcing GRACE’s sensitivity to the main upstream storage component of the Cantareira System. Empirical Orthogonal Function (EOF) decomposition of the InSAR deformation fields, retaining the first four modes (72% of variance in Upper Tietê, 66% in PCJ), further demonstrates that deformation patterns are strongly influenced by hydrogeological controls, with distinct spatial responses between the PCJ basin, where hydroclimatic forcing is more pronounced, and the more urbanized and anthropogenically influenced Upper Tietê basin. The integrated dataset captures major drought episodes between January 2020 and Dicember 2025, demonstrating the capability of combining GPS, InSAR, and GRACE observations to quantitatively link climatic drought forcing, terrestrial water storage deficits, and surface deformation, thereby providing a robust approach for monitoring water storage changes and supporting water resource management in densely populated regions. Full article

Lumpy skin disease (LSD) is a rapidly expanding transboundary vector-borne disease threatening livestock systems across Asia, with increasing risk of introduction into previously unaffected regions such as South Korea. This study developed an integrated, spatially explicit framework to assess the plausibility, timing and source-region structure of LSD virus (LSDV) introduction via windborne dispersal of infected arthropod vectors. Maximum Entropy models based on climatic, environmental, and topographic variables were used to determine habitat suitability for four major vector families (Culex spp., Musca domestica, Stomoxys calcitrans, and Culicoides spp.). All four were run via the transport simulation; S. calcitrans had the best experimental transmission efficiency, whereas Culicoides spp. provides the strongest evidence for passive long-distance transport. Livestock density and vector suitability were used to calculate the risk of LSD incidence in the adjacent source regions. A fourth-order Runge–Kutta trajectory model driven by ERA5 reanalysis winds at 850 hPa (about 1458 m) was used to predict windborne dissemination. This model included degradation of mechanically transmitted virus as well as survival limitations based on temperature, humidity, and wind. The simulated trajectories arrived in South Korea within the retention period of mechanically transported LSDV, with a median transit time of 18 h (interquartile range 10.0–30.3 h), 61.4% arriving within 24 h, and 87.1% within 48 h. North Korea accounted for 76.5% of weighted arrivals, with a median transit time of 11 h. Transit durations varied significantly by source location. For all four vector species, the predicted infectious arrival mass peaked in September and decreased thirteen-fold by November. Infected farms were found in regions of greater anticipated exposure than non-infected controls when compared to the October 2023 Korean epidemic (58.1% vs. 34.3% in the two highest risk groups; median exposure 0.214 versus 0.045; p < 0.001), although randomly relocating the dispersal surface reproduced comparable agreement in 23.6% of permutations, indicating that outbreak locations provide only limited validation of a pathway-specific introduction model. Random permutation of the dispersion surface produced a comparable result in 23.6% of permutations, indicating limited robustness of the observed spatial relationship to spatial randomization. With pairwise geographical and temporal distances significantly associated (Mantel r = +0.136, p = 0.013), spatiotemporal analysis revealed that the 74 reported outbreaks originated from a maximum of 25 introduction events over a 13-day period, consistent with significant farm-to-farm dissemination after introduction. The seasonal window, source-region structure, and transit timeframes of windborne LSDV introduction into South Korea are described in this paper. Reported epidemic sites only partially validate a pathway-specific introduction model since they reflect both the point of introduction and subsequent local transmission. This evaluation is pathway-specific and does not evaluate overall incursion risk; windborne transport is one of numerous possible introduction paths to consider. Full article

Phyllostachys edulis (Moso bamboo) is a subtropical bamboo species endemic to China and holds substantial economic and ecological value. Ongoing climate change is reshaping the geographic distribution of its suitable habitats. To reveal these climate-driven dynamics, we calibrated the maximum entropy (MaxEnt) species distribution model using the ENMeval R package version 4.5.2 and evaluated model robustness via spatially independent block cross-validation. We identified nine critical environmental predictors to model spatiotemporal variations in suitable habitats for Moso bamboo, examining both present-day climate and four future periods under four Shared Socioeconomic Pathway (SSP) scenarios. Model performance was optimized at regularization multiplier (RM) of 1.5 with the feature class combination LQHPT, yielding a spatial validation AUC of 0.9104 and robust predictive capacity. Environmental controls were dominated by mean temperature of the coldest quarter (bio11, 63.9% relative contribution) and precipitation of the driest quarter (bio17, 31.2%), while soil clay and organic carbon content modulated suitability at local scales. Under current conditions, the total suitable habitat area encompasses approximately 218.88 × 10⁴ km², with the majority distributed throughout the subtropical zone of southeastern China. Under nearly all future scenarios, high-suitability habitats showed a general contracting trend of 20.94%–95.29% relative to the current baseline, while moderate-suitability habitats exhibited a fluctuating expansion trend, reaching a peak increase of 47.90% in the 2030s under SSP585, but contracted by 18.65% in the 2090s. Meanwhile, habitat centroids underwent small-scale oscillatory shifts in multiple directions and remained entirely within Hunan Province across all periods. MESS analysis confirmed that 90.60%–99.82% of China’s land area fell within climate-analogous ranges, indicating low extrapolation risk for core habitat projections. Core climate refugia with high cross-scenario stability were primarily concentrated in the traditional bamboo-producing regions of southeastern China. This study provides a scientific basis for the sustainable management of Moso bamboo resources, biodiversity conservation, and ecological risk prevention in the context of ongoing climate change. Full article

Contemporary rural public buildings in China are undergoing a critical transition from single-function administrative facilities to multifunctional hubs that integrate public services, industrial support, cultural inheritance, and community interaction. However, existing studies predominantly rely on isolated case descriptions or region-specific practices, lacking systematic synthesis of their functional composition and design mechanisms. To address this gap, this study adopts a qualitative multiple-case analysis of 42 representative rural public service buildings completed after 2018 across China’s five major climatic zones. Through a systematic three-layer coding framework—functional configuration, spatial organization, and environmental strategy—cross-case comparisons were conducted to identify recurring compositional patterns and design strategies. The findings reveal a hierarchical “Three-Core, Six-Auxiliary” functional composition pattern, anchored by convenience, production, and cultural services as cores, supplemented by skills transmission, digital stations, shared storage, exhibition sales, mutual-aid services, and reusable facilities. A four-type design strategy system is distilled: “sharing–activation” for functional complexity, “narrative–identity” for cultural locality, “region–prototype” for climate responsiveness, and “material–craftsmanship” for ecological inheritance. This framework not only clarifies the hierarchical organization between core and auxiliary functions but also demonstrates how these strategies synergistically optimize resource allocation, sustain vernacular heritage, and support low-carbon goals. This study provides a testable and transferable design paradigm, moving rural public building practices beyond empirical intuition toward evidence-based methodological guidance. Full article

The Samara River is a left-bank tributary of the Volga with a total basin area of 46,500 km², of which 22,800 km² is the gauged area analyzed in this study. This river system serves as a case study for examining hydrological transformations in the extreme southeastern region of European Russia (the Southern Cis-Urals) driven by progressive climate change and historical land-use shifts. To achieve this, the study analyzes long-term, station-based gauge observations of monthly river runoff for the period 1933–2022. The methodology employs a baseline set of standard statistical criteria combined with specialized hydromathematical procedures to evaluate runoff structure. The results demonstrate that while the river’s annual runoff lacked a statistically significant trend, its intra-annual structure underwent profound transformations. While April and May exhibited non-significant declines, the vast majority of months demonstrated prominent upward runoff trends. This systematic increase compressed the amplitude between hydrologically contrasting months by a factor of 2.5 to 3 from the historical climatological baseline (1933–1960) period to the modern baseline (1991–2020) period. Since 1989, the intra-annual variability coefficient has decreased by approximately one-third, especially during low-flow years. Concurrently, the spring flood contribution decreased by approximately 25%, and the frequency of prolonged, three- to four-month snowmelt-driven freshets during the 1987–2022 period doubled to ~22% compared to the preceding period, whereas the summer–autumn and winter low-flow shares increased substantially. Spectral analysis demonstrates a structural asymmetry in runoff generation mechanisms: low-flow dynamics are predominantly governed by long-term macrocycles (spanning 11 years or more), whereas maximum discharge exhibits a complex spectral configuration rather than a purely stochastic white noise process, reflecting an underlying statistical ambiguity between the applied criteria. Finally, five alternating multiyear flow phases occurred since 1933, characterized by low-flow conditions during 1933–1945, 1966–1984, and 2014–2022, and high-flow conditions during 1946–1965 and 1985–2013, with the respective contributions of the spring snowmelt flood and low-flow runoff differing substantially across these phases. This research advances the understanding of regional river runoff transformations in the Anthropocene, providing an objective basis for long-term water balance forecasting in the Southern Cis-Urals, strategic environmental management, climate change adaptation, and environmental risk assessment. Full article

Dongting Lake is one of the most important floodplain lakes in China and plays a critical role in regional flood regulation, ecological conservation, and water-resource management. Understanding long-term variations in lake water storage is therefore essential for evaluating hydrological responses to climate change and human activities. In this study, a hydrodynamic-simulation-based storage estimation framework was developed to quantify wet-season water storage variations in Dongting Lake during 1990–2022. The proposed estimation equation showed strong agreement with hydrodynamic-simulation-derived water storage, with a coefficient of determination (R²) of 0.972 and a root mean square error (RMSE) of 0.86 billion m³. Results indicate that both annual peak water storage and mean wet-season water storage exhibited significant declining trends over the study period. Mann–Kendall analysis revealed an evident decrease in peak storage after 2008 and a major hydrological transition around 2003, corresponding to the initial operation of the Three Gorges Dam (TGD). Comparative analysis showed that the average annual peak storage decreased from 17.27 billion m³ during 1990–2002 to 14.41 billion m³ during 2003–2022, while mean wet-season storage decreased from 8.16 billion m³ to 7.23 billion m³. Reduced inflow from both the Yangtze River and the Four Rivers was identified as the dominant factor controlling the decline in water storage. Although lakebed erosion increased the potential storage volume associated with bathymetric evolution by approximately 0.95 billion m³, its contribution was substantially smaller than the reduction in inflow runoff. Although long-term storage decreased, Dongting Lake retained substantial flood-regulation capacity, with only limited changes observed in flood-retention performance during major flood events. The findings contribute to a better understanding of long-term hydrological changes in Dongting Lake and provide useful information for flood control and water-resource management in the middle Yangtze River basin. Full article

Dissolved organic carbon (DOC) is a climate-sensitive component of carbon cycling in inland waters, but consistent regional comparisons of its seasonal and interannual patterns remain limited across China. Here, we conducted a secondary analysis of a published monthly DOC dataset for 60 selected lake and reservoir series (15 per climate region) spanning China’s subtropical monsoon, temperate monsoon, temperate continental, and plateau mountainous regions during 2000–2023. The source dataset was generated using random forest models constrained by 1326 DOC observations from 83 lake and reservoir stations, and with watershed-scale climate, soil, and anthropogenic variables used as predictors. Across the four regions, the long-term mean DOC concentrations were 9.78, 14.10, 16.12, and 15.14 mg L⁻¹, respectively. Seasonal medians showed spring–summer enrichment in the two monsoon regions, nearly equal spring and summer values in the temperate continental region, and an autumn maximum in the plateau mountainous region. Interannual variability was greatest in the subtropical monsoon region (CV = 3.18%), whereas the plateau mountainous region had the lowest variability (CV = 0.95%). Mann–Kendall analysis identified a significant decline only in the temperate continental region (Z = −2.51, p = 0.012). These results provide a climate–region synthesis of model-derived DOC patterns in Chinese inland waters. Because climate variables contributed to the original random forest predictions, the present study interprets regional contrasts descriptively rather than as independent causal evidence of climatic controls. Full article

The Fusarium graminearum species complex (FGSC) is a major causal agent of Fusarium head blight (FHB) and trichothecene contamination in cereal cropping systems worldwide. However, its major species-genotype groups exhibit distinct differences in environmental adaptability and spatial distribution. Using a host-informed MaxEnt modeling framework, this study compared the global potential environmental suitability of four major FGSC groups, namely Fusarium asiaticum-DON (Fa-DON), Fusarium asiaticum-NIV (Fa-NIV), Fusarium graminearum-DON (Fg-DON), and Fusarium graminearum-NIV (Fg-NIV), under the 1970–2000 baseline and four SSPs across four future periods. By integrating georeferenced occurrence records with continuous host-related, climatic, soil, topographic, and wind predictors, and applying four-fold spatial cross-validation, we identified distinct intergroup suitability patterns. Under current conditions, Fg-DON showed the broadest highly suitable area, whereas Fa-DON was the most restricted. Both F. asiaticum groups were centered in Asia, while Fg-NIV was concentrated mainly in Europe. Future projections indicated consistent expansion for Fg-DON and general contraction for Fa-DON. Fa-NIV remained comparatively stable, whereas Fg-NIV showed scenario-dependent contraction or expansion. These changes reflected regional redistribution rather than a uniform shift across groups. Collectively, our findings indicate that FGSC suitability should be interpreted as a set of differentiated, group-specific biogeographic patterns, which provide a more targeted scientific basis for surveillance strategies and regional risk assessment of FHB and trichothecene contamination under changing environmental conditions. Full article

Drought monitoring in arid regions commonly relies on climatic indices, yet the accumulation timescale that best represents surface soil moisture drought may vary spatially. This study evaluated the Standardized Precipitation Evapotranspiration Index (SPEI) at 1-, 3-, and 6-month accumulation periods against satellite-derived surface soil moisture across Saudi Arabia during 2003–2024. Temporal correspondence, grid-cell Spearman correlation, and receiver operating characteristic area under the curve (ROC-AUC) were evaluated. The analysis included 1462 grid cells meeting the minimum paired-observation criterion, representing 53.4% of the 2736 cells in the national domain. SPEI-1 consistently showed the strongest overall performance, with the highest temporal correspondence with surface soil moisture drought extent ($\rho =0.50$, versus 0.37 for SPEI-3 and 0.30 for SPEI-6), median grid-cell correlation ($\tilde{\rho }=0.290$, versus 0.255 and 0.175), and median ROC-AUC (0.629, versus 0.618 and 0.580). SPEI-1 was also the nominal highest-AUC timescale in 52.5% of analyzed cells, compared with 29.5% for SPEI-3 and 17.9% for SPEI-6. However, the median AUC difference between the first- and second-ranked timescales was only 0.033, and paired bootstrap comparisons showed that 94.8% of cells had no uniquely supported AUC winner. Regionally, nine of the 13 administrative regions showed a nominal majority preference for SPEI-1, whereas four had no single-timescale majority. The overall SPEI-1 > SPEI-3 > SPEI-6 ordering was also preserved under alternative soil moisture drought thresholds and temporal out-of-sample validation. These findings indicate that shorter SPEI accumulation periods generally provide the closest representation of near-surface soil moisture drought within the observed Saudi domain. The results provide practical guidance for selecting SPEI accumulation periods according to the land-surface drought process being monitored. Full article

Climate change drives shifts in forest vegetation zones, and the major tree species of warm–temperate evergreen broad-leaved forests in South Korea are also expected to undergo changes in their potential distributions under future climate conditions. This study applied a Committee Averaging (CA) ensemble species distribution model to Quercus acuta, Machilus thunbergii, Quercus glauca, and Castanopsis sieboldii to project changes in their potential distributions under four Shared Socioeconomic Pathway (SSP) scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) across two future periods (2050s and 2090s). To compare interspecific differences in response more clearly, we applied a two-tier threshold scheme that distinguished potential habitat (agreement ≥0.6) from highly suitable habitat (>0.8), and we concurrently conducted a Multivariate Environmental Similarity Surface (MESS) analysis to assess predictive uncertainty arising from extrapolation into future climates. The CA ensemble models showed excellent predictive performance (AUC 0.947–0.989; TSS 0.837–0.943). For Q. acuta, M. thunbergii, and Q. glauca, potential habitat expanded consistently across all SSP scenarios, and highly suitable habitat shifted northward into parts of the central and Gangwon regions. In contrast, both the potential habitat and the highly suitable habitat of C. sieboldii contracted under most future scenarios. These results demonstrate that even species belonging to the same warm–temperate evergreen broad-leaved forest community can respond differently to future climate. The two-tier threshold scheme applied in this study was effective not only for assessing whether distributions expand but also for delineating and evaluating climatically stable core habitats. Although our findings need to be interpreted in light of the uncertainty associated with extrapolation into future climates, they can serve as useful baseline data for establishing climate-change-adaptive forest conservation and species-specific management strategies. Full article

How modeled ecosystem carbon balance varies across the contrasting hydroclimatic zones of the Yellow River Basin, and whether its relationships with climate extremes differ among these zones, remain insufficiently understood. To address this knowledge gap, this study examined the spatiotemporal variability of modeled net ecosystem productivity (NEP) and its associations with temperature- and precipitation-extreme indices across three major ecological zones of the basin. Using satellite-derived NDVI, reanalysis climate data, and extreme climate indices for 2000–2022, we estimated NEP from CASA-simulated net primary productivity and modeled heterotrophic respiration, and assessed its temporal trends and climatic associations across three ecological zones. Three principal findings were obtained: (1) Over the 23-year study period, basin-wide NEP showed a statistically significant increasing tendency (β = 2.699 g C m⁻² a⁻¹), with a well-defined spatial gradient characterized by relatively lower productivity in the northwestern areas and elevated productivity toward the southeastern regions. (2) Modeled NEP increased across all four seasons. Summer showed the largest positive trend, whereas autumn and winter remained net carbon-release seasons but became progressively less negative over the study period. (3) The statistical associations between modeled NEP and extreme climate indices varied markedly across ecological zones. Extreme-precipitation indices were generally positively associated with modeled NEP in the arid northwestern zone, whereas several extreme-temperature indices showed predominantly negative associations in the northeastern monsoon-influenced region. Collectively, these findings provide model-based evidence of spatially differentiated associations between ecosystem carbon balance and climate extremes across the YRB, supporting regional ecosystem assessment and climate-adaptation planning. Full article

Soil salinization and alkalization caused by global climate change have become major constraints on crop production worldwide. Quinoa (Chenopodium quinoa Willd.), owing to its exceptional adaptability to adverse environmental conditions, is considered a promising crop for saline–alkali agriculture. Successful screening and evaluation of saline–alkali-tolerant germplasm at the germination stage is essential for breeding quinoa varieties with enhanced tolerance to compound saline–alkali stress. In this study, 23 quinoa accessions originating from different regions were evaluated for saline–alkali tolerance by exposing seeds to compound saline–alkali solutions at different concentrations in a Petri dish germination assay. During the germination stage, relative vigor index, germination rate, germination energy, shoot length, root length, and fresh weight were determined, and saline–alkali tolerance was assessed using multivariate statistical analyses. The germination ability and seedling growth potential of quinoa germplasm gradually declined with increasing saline–alkali stress. Based on the comprehensive saline–alkali tolerance index at the germination stage, eight accessions were identified as highly tolerant and four accessions as highly sensitive to saline–alkali stress. Among them, LL1 and Z27 exhibited outstanding tolerance and were identified as elite saline–alkali-tolerant germplasm resources. The results indicated that vigor index and fresh weight at the germination stage can serve as key parameters for evaluating saline–alkali tolerance in quinoa germplasm. Overall, this study provides valuable germplasm resources and a practical basis for breeding new quinoa varieties with enhanced saline–alkali tolerance, as well as for the identification and utilization of stress-resistance-related genes in quinoa. Full article

The growing interest in natural bioactive compounds has positioned sea buckthorn (Hippophae rhamnoides L.) as a source of high-value phytochemicals for pharmaceutical and functional applications. Renowned for its complex biochemical profile, this species synthesizes significant levels of lipophilic and hydrophilic antioxidants, notably carotenoids and ascorbic acid (vitamin C). These constituents provide extensive therapeutic and pharmacological benefits, including strong antioxidant, anti-inflammatory, and tissue-regenerative properties. Consequently, characterizing the exact bioactive composition of sea-buckthorn is essential for identifying cultivars with exceptional multi-functional potential. However, a major challenge in exploiting this botanical resource lies in the significant variability of its chemical profile. While the fundamental pharmacological attributes of the plant are genetically determined, the absolute concentration of its bioactive compounds can vary. Factors such as specific cultivar traits and inter-annual climatic conditions, including severe seasonal droughts, are known to influence secondary metabolite accumulation. Although individual varieties exhibit distinct nutritional profiles, systematic data tracking these fluctuations over consecutive years remain limited, particularly regarding certified cultivars adapted to specific regional ecosystems. To extend current understandings, this study evaluates the multi-functional characteristics and inter-annual stability of 17 distinct sea buckthorn varieties over a continuous three-year monitoring period. Specifically, this research focuses on four select varieties officially registered in the Republic of Moldova Official Catalogue of Plant Varieties and Species. The primary aim of this investigation is twofold: first, to quantify key quality parameters—including carotenoid levels, vitamin C content, total acidity, pH, and dry matter—across the different cultivars; and second, to determine whether genetic variety or inter-annual climatic variations exert the dominant influence on these bioactive levels over the medium term. By evaluating these parameters, this study establishes reliable baselines for selecting stable, high-yield cultivars optimized for targeted pharmacological applications. Full article

Drought is a major climatic hazard affecting agricultural production and water resource management. This study investigates the spatiotemporal evolution of summer drought across nine major agricultural regions in China and quantifies associated uncertainties under historical (1981–2010) and future periods (2041–2070 and 2071–2100). Using multi-model simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) under four SSP scenarios (SSP126, SSP245, SSP370, and SSP585), drought variations were characterized using the Standardized Precipitation Index at a 3-month timescale (SPI-3). Sen’s slope estimator combined with the Mann–Kendall test was applied to detect drought trends, and factorial analysis was used to quantify uncertainty contributions. Results show pronounced regional differences in historical drought conditions, with northern arid and semi-arid regions exhibiting stronger precipitation deficits (mean SPI-3 = −0.435), while the Yangtze River Plain and Northeast China Plain show wetter conditions. Historical trends indicate increasing drought conditions in South China, whereas humidification trends dominate several northern and eastern regions. Under future scenarios, most regions show overall wetting trends, but drying tendencies persist in South China. Factorial analysis reveals that regional differences (58.34%) and climate model uncertainty (31.15%) are the dominant contributors to drought variability. Overall, future summer drought in China is characterized by a general wetting tendency with localized intensification of drought conditions. Full article

Drought is one of the major factors affecting terrestrial ecosystem functioning under climate change. However, the interactions among different drought indices and the response of gross primary productivity (GPP) to them remain unclear. This study used multi-source remote sensing data of China from 2003 to 2020, employing the standardized precipitation evapotranspiration index (SPEI), temperature condition index (TCI), soil moisture condition index (SMCI), and vegetation condition index (VCI) to characterize the spatiotemporal dynamics of drought and quantify the response mechanism between drought indices and GPP. Partial correlation analysis and structural equation modeling were used to distinguish the direct and indirect effects of different drought types on GPP. The results show that GPP exhibited a fluctuating upward trend from 2003 to 2020, ranging from 163.71 to 458.56 g C·m⁻². In 2005, GPP declined significantly across most regions of China relative to 2004, decreasing by 14.47% in North China, 13.93% in Central China, 12.05% in East China, 8.45% in South China, 4.21% in Northwest China, and 4.15% in Northeast China, whereas Southwest China exhibited a slight increase of 0.34%. Different types of drought exhibited distinct occurrence characteristics. SMCI exhibited a drought frequency of 44.35% and a mean duration of 75.64 days. Among the four indices, SPEI showed the lowest frequency (12.54%) and the highest intensity (0.14), whereas TCI exhibited both the highest frequency (60.22%) and the longest duration (98.46 days), and VCI yielded the lowest drought severity (1.96). The TCI was considered a major driver of GPP variations, showing a significant positive correlation with GPP in all regions (r = 0.45–0.88, p < 0.001). In contrast, the SPEI had a relatively weak impact on GPP. The “TCI→VCI → GPP” pathway represented the main pathway of drought–GPP interaction at the national scale. This study provides methods for assessing the response characteristics of GPP under future climate change. Full article