Spatial Response Patterns Research Articles

Functional preference and spatial response of urban renewal entities in Beijing

In the process of rapid urban renewal, quantitative research on functional preferences and spatial layout norms of multi-type urban renewal entities is crucial for optimizing spatial governance and promoting orderly control of urban renewal. We investigate urban renewal in Beijing from 2006 to 2021 using directional distribution, spatial autocorrelation, and hotspot analysis. The findings are as follows: (1) The functional preference of each type of entity differs. While most private companies and other profit-oriented entities concentrate on producer services and residential functions, policy-oriented entities dominate the urban regeneration of public service activities. (2) Every entity shows a significant agglomeration characteristic, yet exhibits a differentiated spatial response pattern. Those entities with stronger leasing ability prefer the central zone while others are the opposite. (3) Diverse types of entities have differentiated spatiotemporal evolutions. The spatial directional divergence of state-owned enterprises and scientific research institutes has increased between 2006 and 2021. This is mainly influenced by the policy of relieving Beijing of nonessential functions. However, the rest entities show a balanced spatial development trend with the difference in each direction becoming smaller. Furthermore, the center of gravity of profit-oriented entities has shifted from the suburbs to the central zone due to a combination of administrative and market forces, whereas the center of gravity of policy-oriented entities tends to move outward from the central zone.

No Future Growth Enhancement Expected at the Northern Edge for European Beech due to Continued Water Limitation.

With ongoing global warming, increasing water deficits promote physiological stress on forest ecosystems with negative impacts on tree growth, vitality, and survival. How individual tree species will react to increased drought stress is therefore a key research question to address for carbon accounting and the development of climate change mitigation strategies. Recent tree-ring studies have shown that trees at higher latitudes will benefit from warmer temperatures, yet this is likely highly species-dependent and less well-known for more temperate tree species. Using a unique pan-European tree-ring network of 26,430 European beech (Fagus sylvatica L.) trees from 2118 sites, we applied a linear mixed-effects modeling framework to (i) explain variation in climate-dependent growth and (ii) project growth for the near future (2021-2050) across the entire distribution of beech. We modeled the spatial pattern of radial growth responses to annually varying climate as a function of mean climate conditions (mean annual temperature, mean annual climatic water balance, and continentality). Over the calibration period (1952-2011), the model yielded high regional explanatory power (R2 = 0.38-0.72). Considering a moderate climate change scenario (CMIP6 SSP2-4.5), beech growth is projected to decrease in the future across most of its distribution range. In particular, projected growth decreases by 12%-18% (interquartile range) in northwestern Central Europe and by 11%-21% in the Mediterranean region. In contrast, climate-driven growth increases are limited to around 13% of the current occurrence, where the historical mean annual temperature was below ~6°C. More specifically, the model predicts a 3%-24% growth increase in the high-elevation clusters of the Alps and Carpathian Arc. Notably, we find little potential for future growth increases (-10 to +2%) at the poleward leading edge in southern Scandinavia. Because in this region beech growth is found to be primarily water-limited, a northward shift in its distributional range will be constrained by water availability.

FMRI speech tracking in primary and non-primary auditory cortex while listening to noisy scenes

Invasive and non-invasive electrophysiological measurements during “cocktail-party”-like listening indicate that neural activity in the human auditory cortex (AC) “tracks” the envelope of relevant speech. However, due to limited coverage and/or spatial resolution, the distinct contribution of primary and non-primary areas remains unclear. Here, using 7-Tesla fMRI, we measured brain responses of participants attending to one speaker, in the presence and absence of another speaker. Through voxel-wise modeling, we observed envelope tracking in bilateral Heschl’s gyrus (HG), right middle superior temporal sulcus (mSTS) and left temporo-parietal junction (TPJ), despite the signal’s sluggish nature and slow temporal sampling. Neurovascular activity correlated positively (HG) or negatively (mSTS, TPJ) with the envelope. Further analyses comparing the similarity between spatial response patterns in the single speaker and concurrent speakers conditions and envelope decoding indicated that tracking in HG reflected both relevant and (to a lesser extent) non-relevant speech, while mSTS represented the relevant speech signal. Additionally, in mSTS, the similarity strength correlated with the comprehension of relevant speech. These results indicate that the fMRI signal tracks cortical responses and attention effects related to continuous speech and support the notion that primary and non-primary AC process ongoing speech in a push-pull of acoustic and linguistic information.

Unraveling the impact of dog‐friendly spaces on urban–wildland pumas and other wildlife

As the most widespread large carnivore on the planet, domestic dogs Canis lupus familiaris can pose a major threat to wildlife, even within protected areas (PAs). Growing human presence in PAs, coupled with increasing pet dog ownership underscores the urgency to understand the influence of dogs on wildlife activity and health. This knowledge can mitigate the adverse repercussions of recreation, optimizing PA management. Drawing on five years (2017–2021) of data from 101 camera traps in the San Francisco Bay Area, California, United States, we measured the spatiotemporal responses of puma Puma concolor, bobcat Lynx rufus, coyote Canis latrans, and mule deer Odocoileus hemionus towards domestic dogs. Additionally, using six years (2017–2022) of community science data, we explored the impacts of PA dog policies on puma sightings outside park boundaries. Puma responses provide insights into broader ecological impacts, while analyses of bobcat, coyote, and mule deer offer a comprehensive understanding of species responses to dog‐friendly spaces. Because dogs can be perceived as predators or competitors by wildlife, we anticipated shifts in spatial and temporal activity patterns in response to dogs. Wildlife responses included avoidance (bobcat, puma) or spatial overlap (mule deer) for areas with more dogs, and no effect (coyote). Mule deer may benefit from a “human shield” provided by people with dogs, while pumas and bobcats appeared more sensitive, and coyotes more adaptable. Dog policies influenced puma and mule deer temporal activity, with increased nocturnal activity in dog‐friendly PAs. Bobcat temporal activity was less variable in dog‐friendly PAs and coyote activity was similar between treatments. Outside PAs, puma sightings increased with human disturbance. Our study underscores the trade‐offs between recreation and wildlife conservation, emphasizing the need to quantify the ecological impacts of dogs. This understanding is vital for informing conservation strategies and promoting coexistence between dogs, wildlife, and protected environments.

Auditory cortex encodes lipreading information through spatially distributed activity

Watching a speaker's face improves speech perception accuracy. This benefit is enabled, in part, by implicit lipreading abilities present in the general population. While it is established that lipreading can alter the perception of a heard word, it is unknown how these visual signals are represented in the auditory system or how they interact with auditory speech representations. One influential, but untested, hypothesis is that visual speech modulates the population-coded representations of phonetic and phonemic features in the auditory system. This model is largely supported by data showing that silent lipreading evokes activity in the auditory cortex, but these activations could alternatively reflect general effects of arousal or attention or the encoding of non-linguistic features such as visual timing information. This gap limits our understanding of how vision supports speech perception. To test the hypothesis that the auditory system encodes visual speech information, we acquired functional magnetic resonance imaging (fMRI) data from healthy adults and intracranial recordings from electrodes implanted in patients with epilepsy during auditory and visual speech perception tasks. Across both datasets, linear classifiers successfully decoded the identity of silently lipread words using the spatial pattern of auditory cortex responses. Examining the time course of classification using intracranial recordings, lipread words were classified at earlier time points relative to heard words, suggesting a predictive mechanism for facilitating speech. These results support a model in which the auditory system combines the joint neural distributions evoked by heard and lipread words to generate a more precise estimate of what was said.

Spatial Distribution Pattern of Response of Quercus Variabilis Plantation to Forest Restoration Thinning in a Semi-Arid Area in China

Plantations are increasing in frequency and extent across the landscape, especially in China, and forest thinning can accelerate the development of late-successional attributes, thereby enhancing plantation stand structural heterogeneity. To quantify the effect of forest restoration thinning on the spatial heterogeneity and the structure of Quercus variabilis plantations, a restoration thinning experiment in a 40-year-old Quercus variabilis plantation by removing trees from the upper canopy level was conducted; two one-hectare sample plots with thinning and a control (i.e., unlogged) were sampled; and geostatistics methods were used to analyze the spatial distribution pattern of the DBH, height, and density of the stand. We found that restoration forest thinning in the Quercus variabilis plantation had a significant impact on the average DBH and tree height of the stand. Meanwhile, the coefficient of variation and structure ratio of the DBH, tree height, and stand density in the thinning plot were larger than those in the control plot. The range and spatial autocorrelation distance of the DBH and stand density in the thinning plot were smaller than those in the control plot, but the fractal dimension showed the opposite trend. The range and spatial autocorrelation distance of tree height in the thinning plot were higher than those in the control plot. These findings suggested that, compared with the control plot, the stereoscopic distribution of the DBH and stand density in the thinning plot fluctuated less and changed gentler, and its spatial continuity was not high but its variation was significant; meanwhile, the stereoscopic distribution of the tree height in the thinning plot was highly fluctuating and changed more significantly, with a strong spatial dependence and strip gradient distribution. Hence, forest restoration thinning could improve the distribution of the DBH and stand density and adjust the spatial heterogeneity of the DBH, tree height, and stand density of Quercus variabilis plantations.

Lower Thermospheric Temperature Response to Geomagnetic Activity at High Latitudes

AbstractThe magnetosphere‐ionosphere‐thermosphere system is externally driven by the energy input from the solar wind. A part of the solar wind energy deposited in the magnetosphere during geomagnetically active periods dissipates into the thermosphere. Previous studies have reported temperature perturbations in the lower thermosphere during geomagnetic storms. The present study aims to assess the climatological spatial pattern of the lower thermospheric response to geomagnetic activity at high latitudes based on 21 years of temperature measurements by the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument onboard the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) satellite and their comparison with the recently developed half‐hourly geomagnetic activity index Hp30. The temperature response to geomagnetic activity, evaluated at different seasons and altitudes, is better organized in magnetic coordinates than in geographic coordinates. At 110 km, the temperature increases with Hp30 at all magnetic local times, but with a prominent dusk‐dawn asymmetry in the magnitude. That is, the temperature variation per unit Hp30 is larger in the dusk sector than in the dawn sector. At 106 km, the response in the dawn sector is further reduced or even negative. These results provide observational evidence to support earlier theoretical predictions; according to which, both storm‐induced vertical wind and Joule heating contribute to the temperature increase in the dusk sector, while in the dawn sector, the vertical wind acts to cool the air and thus counteracts Joule heating.

Drought-tolerant peanut (Arachis hypogaea L.) varieties can mitigate negative impacts of climate change on yield in the Southeastern U.S.

Rising temperatures and varying precipitation patterns in future climates pose huge challenges to the peanut (Arachis hypogaea L.) production in Southeastern U.S. (SEUS), which was characterized by hot summers and mild winters. This will require genetic improvement of peanut varieties for adapting to future climates for higher yields. Recently, several novel peanut varieties were found to exhibit higher yield and maintain photosynthesis during drought. Thus, this study aimed to investigate the spatial and temporal patterns of peanut yield response to future climate changes for peanut varieties with and without the drought tolerant trait of maintaining photosynthesis (MPh) under drought in the SEUS and evaluate the relative importance of yield related traits for enhancing yield advantage of peanut under future climate conditions. A modified version of the CROPGRO-Peanut model incorporating the drought tolerant factor was developed and validated using field trail data collected from distinct experimental sites under both rainfed and irrigated conditions. Yield was then simulated for the historical baseline period (1990–2021) and future (mid-century/2050s, late-century/2080s) climate scenarios across the SEUS. The results showed that peanut yield in the Northern SEUS was expected to benefit from climate change in the 2050s (RCP4.5 and RCP8.5), but Middle SEUS and Southern SEUS would experience high probability of yield loss in the future. Comparing to the reference variety (C4), the drought tolerant peanut varieties (C1, C2 and C3) with the trait of MPh under drought could enhance the yield gains due to future climates in the 2050s (RCP4.5 and RCP8.5) in Northern SEUS (yield increases from 5% to 10% for C1-C3, and 2% to 3% for C4) and mitigate the negative impacts of climate change in the 2080s (RCP4.5 and RCP8.5) in the Middle (yield changes from −26% to −1% for C1-C3, and −37% to −11% for C4) and Southern SEUS (yield changes from −24% to 1% for C1-C3, and −35% to −7% for C4). The yield advantage of the drought tolerant peanut varieties in future climates was strongly associated with the higher water use efficiency (WUE), harvest index (HI), seed size, seed number, and biomass with significant P values (p < 0.001). These findings are important for local breeding and management programs to mitigate the potential impacts of climate change on peanut yield in SEUS.

Spatial analysis of aerial remote sensing responses in the hotspot of terrorist attacks in Nigeria

ABSTRACT Ensuring a peaceful society has been the focus of different countries of the world. This has been jeopardized by the constant attacks from different terrorist groups, which has made some areas become the hotspot of terrorist attacks. Various techniques including remote sensing technology have been applied in curbing the attacks. However, an understanding of the spatial pattern of remote sensing responses to terrorist attacks especially in the hotspot areas will enhance the decision-makers and stakeholders’ better planning against terrorists. We present that the spatial analysis of the trend and pattern of terrorist attacks and aerial remote sensing responses in the hotspot of Nigeria using the Getis-Ord General tool in ArcGIS 10.8. We conclude that aerial remote sensing responses against terrorist attacks can be more effective if the spatial pattern of attacks and responses can be constantly considered in security monitoring and surveillance for both pro-active and counter-attack operations.

Dissociable Contributions of the Medial Parietal Cortex to Recognition Memory.

Human neuroimaging studies of episodic memory retrieval routinely observe the engagement of specific cortical regions beyond the medial temporal lobe. Of these, medial parietal cortex (MPC) is of particular interest given its distinct functional characteristics during different retrieval tasks. Specifically, while recognition and autobiographical recall tasks are both used to probe episodic retrieval, these paradigms consistently drive distinct spatial patterns of response within MPC. However, other studies have emphasized alternate MPC functional dissociations in terms of brain network connectivity profiles or stimulus category selectivity. As the unique contributions of MPC to episodic memory remain unclear, adjudicating between these different accounts can provide better consensus regarding MPC function. Therefore, we used a precision-neuroimaging dataset (7T functional magnetic resonance imaging) to examine how MPC regions are differentially engaged during recognition memory and how these task-related dissociations may also reflect distinct connectivity and stimulus category functional profiles. We observed interleaved, though spatially distinct, subregions of MPC where responses were sensitive to either recognition decisions or the semantic representation of stimuli. In addition, this dissociation was further accentuated by functional subregions displaying distinct profiles of connectivity with the hippocampus during task and rest. Finally, we show that recent observations of dissociable person and place selectivity within the MPC reflect category-specific responses from within identified semantic regions that are sensitive to mnemonic demands. Together, by examining precision functional mapping within individuals, these data suggest that previously distinct observations of functional dissociation within MPC conform to a common principle of organization throughout hippocampal-neocortical memory systems.

Impact of tropical SSTs on the late-winter signal over the North Atlantic-European region and contribution of midlatitude Atlantic

The impact of tropical sea surface temperatures (SSTs) on the signal of geopotential heights (GH200) over the North Atlantic-European (NAE) region is analysed from the aspects of seasonality, the contribution of individual tropical basins and midlatitude North Atlantic, El Niño-Southern Oscillation (ENSO) effect and spatial pattern of the atmospheric response. For this purpose, ensembles of targeted numerical simulations with SST forcing prescribed in various ocean basins are performed and examined. A clear atmospheric response is obtained in the late winter months. The strongest signal is linked to ENSO events during late winter. The competitive influences of individual tropical basins are indicated. At the same time, the superposition effect of the extratropical North Atlantic SSTs, which is established through the modulation of storm tracks, is demonstrated. Both, the modelled signal and the NOAA-CIRES-DOE 20th Century Reanalysis variance reveal the ENSO signature as a pattern in the North Atlantic projecting onto the East Atlantic pattern.

Distinct patterns ofneural response to faces from different races inhumans anddeep networks.

Social categories such as the race or ethnicity of an individual are typically conveyed by the visual appearance of the face. The aim of this study was to explore how these differences in facial appearance are represented in human and artificial neural networks. First, we compared the similarity of faces from different races using a neural network trained to discriminate identity. We found that the differences between races were most evident in the fully connected layers of the network. Although these layers were also able to predict behavioural judgements of face identity from human participants, performance was biased toward White faces. Next, we measured the neural response in face-selective regions of the human brain to faces from different races in Asian and White participants. We found distinct patterns of response to faces from different races in face-selective regions. We also found that the spatial pattern of response was more consistent across participants for own-race compared to other-race faces. Together, these findings show that faces from different races elicit different patterns of response in human and artificial neural networks. These differences may underlie the ability to make categorical judgements and explain the behavioural advantage for the recognition of own-race faces.

Nonlinear control of climate, hydrology, and topography on streamflow response through the use of interpretable machine learning across the contiguous United States

Abstract Runoff has been greatly affected by climate change and human activities. Studying nonlinear controls on runoff response is of great significance for water resource management decision-making and ecological protection. However, there is limited understanding of what physical mechanisms dominate the runoff response and of their predictability over space. This study analyzed the spatial patterns of runoff response including runoff changes and its sensitivity to climate–landscape variations in 1,003 catchments of the contiguous United States (CONUS). Then, an interpretable machine learning method was used to investigate the nonlinear relationship between watershed attributes and runoff response, which enables the importance of influencing factors. Finally, the random forest model was employed to predict runoff response according to the predictors of catchment attributes. The results show that alteration of runoff is up to 56%/10 years due to climate change and human activities. Catchment attributes substantially altered runoff over CONUS (−60% to 56%/10 years). Climate, topography, and hydrology are the top three key factors which nonlinearly control runoff response patterns which cannot be captured by the linear correlation method. The random forest can predict runoff response well with the highest R2 of 0.96 over CONUS.

Comprehensive assessment of baseflow responses to long-term meteorological droughts across the United States

Baseflow is a critical component of streamflow, as it maintains flow during meteorological drought. However, our understanding of baseflow response to meteorological droughts is limited. In this study, we presented a flexible approach for detecting precipitation and baseflow droughts and their corresponding recovery. Using this framework, we analyzed data from 358 anthropogenically unaffected catchments to characterize the droughts and recovery properties of baseflow across the United States. Results showed that baseflow droughts were more severe than the precipitation droughts, with duration ranging between 9–104 months. There were delayed responses of baseflow to precipitation droughts, showing longer-lasting effects up to 41 months after the end of precipitation droughts. Our analysis also revealed that baseflow drought is controlled by climate and hydrologic responses of a catchment, whereas baseflow recovery primarily depends on post-drought climate conditions. Furthermore, the aridity index can differentiate the spatial patterns of baseflow responses to precipitation droughts. Decadal changes in baseflow droughts revealed that baseflow droughts have become more severe and prolonged due in part to the rise in temperature highlighting the impacts of climate change on baseflow in the mild temperate zone. Overall, this study provides comprehensive insights into baseflow drought detection and its response to precipitation droughts and underscores the importance of these processes for sustainable water resource management.

Effects of microplastics on denitrification and associated N2O emission in estuarine and coastal sediments: insights from interactions between sulfate reducers and denitrifiers

Global estuarine and coastal zones are facing severe microplastics (MPs) pollution. Sulfate reducers (SRB) and denitrifiers (DNB) are two key functional microorganisms in these zones, exhibiting intricate interactions. However, whether and how MPs modulate the interactions between SRB and DNB, with implications for denitrification and associated N2O emissions, remains poorly understood. Here, we simultaneously investigated the spatial response patterns of SRB-DNB interactions and denitrification and associated N2O emissions to different MPs exposure along an estuarine gradient in the Yangtze Estuary. Spatial responses of denitrification to polyvinyl chloride (PVC) and polyadipate/butylene terephthalate (PBAT) MPs exposure were heterogeneous, while those of N2O emissions were not. Gradient-boosted regression tree and multiple regression model analyses showed that sulfide, followed by nitrate (NO3−), controlled the response patterns of denitrification to MPs exposure. Further mechanistic investigation revealed that exposure to MPs resulted in a competitive and toxic (sulfide accumulation) inhibition of SRB on DNB, ultimately inhibiting denitrification at upstream zones with high sulfide but low NO3− levels. Conversely, MPs exposure induced a competitive inhibition of DNB on SRB, generally promoting denitrification at downstream zones with low sulfide but high NO3− levels. These findings advance the current understanding of the impacts of MPs on nitrogen cycle in estuarine and coastal zones, and provide a novel insight for future studies exploring the response of biogeochemical cycles to MPs in various ecosystems.

Influence of the Hanjiang River’s Inlet Sediment Decrease on Modern Sedimentation in the Underwater Delta

The Hanjiang River is the second-largest river in Guangdong Province, China. The modern sedimentation pattern of the Hanjiang subaqueous delta has been significantly affected by changes in the sediment delivered by the Hanjiang River. Based on multiperiod charts and columnar samples from the Hanjiang subaqueous delta, the influence of a sharp decrease in the sediment flux from the Hanjiang River on the deposition of the Hanjiang subaqueous delta in the past 60 years was studied through a combination of chart-based analysis of the evolution of erosion and deposition and the analysis of sediment samples. The results showed that the significant reductions in sediment fluxes from the Hanjiang River and Rongjiang River had obviously spatially differentiated effects on the deposition pattern of the Hanjiang subaqueous delta. The significant decreases in sediment fluxes from the Hanjiang River and the Rongjiang River caused the sediment grain size of the columnar samples in the near-estuary area of the Hanjiang River subaqueous delta to coarsen upward, the deposition rate to decrease, and the depositional state to change to an erosional state. Since the sediments discharged into the ocean after reservoir impoundment are mainly fine-grained suspended sediments, the supply of coarse-grained sediments in the Hanjiang subaqueous delta decreased, resulting in the upward fining of the columnar samples. The spatial response pattern of the Hanjiang subaqueous delta to the sharp decrease in sediment flux into the sea differed significantly from those of the Yangtze and Yellow subaqueous deltas.

Prior elicitation for Gaussian spatial process: An application to TMS brain mapping.

The power and commensurate prior distributions are informative prior distributions that incorporate historical data as prior knowledge in Bayesian analysis to improve inference about a phenomenon under study. Although these distributions have been developed for analyzing non-spatial data, little or no attention has been given to spatial geostatistical data. In this study, we extend these informative prior distributions to a Gaussian spatial process, which enables the elicitation of prior knowledge from historical geostatistical data for Bayesian analysis. Three informative prior distributions were developed for spatial modeling, and an efficient Markov Chain Monte Carlo algorithm was developed for performing Bayesian analysis. Simulation studies were used to assess the adequacy of the informative prior distributions. Hierarchical models combined with the developed informative prior distributions were applied to analyze transcranial magnetic stimulation (TMS) brain mapping data to gain insights into the spatial pattern of a patient's response to motor cortex stimulation. The study quantified the uncertainty in motor response and found that the primary motor cortex of the hand is responsible for most of the movement of the right first dorsal interosseous muscle. The findings provide a deeper understanding of the neural mechanisms underlying motor function and ultimately aid the improvement of treatment options for individuals with health issues.

ENHANCING THE CONNECTION BETWEEN PEOPLE AND HERITAGE THROUGH SOCIAL MEDIA IN CHINA

Abstract. Although numerous participatory methods and assessments have been tested in the western context, the community participation practice is still limited in China, a developing country. In addition, due to the diversity of cultural, historical, economic, and social backgrounds, Chinese community participation differs from similar international approaches. Hence it is critical to explore how engaging Chinese people with their own heritage properties can foster stewardship, multi-stakeholder connection, and support policy and strategy making.It is very challenging to preserve the character of historic urban landscapes because they change over time in a rapidly developing urban context. Research on revealing people's stories and preferences concerning the Chinese historic urban landscape in their visiting and living experience is needed to address this concern directly. The study applies a novel approach to explore public attitudes based on the fusion of social media data, land use data and other information. It examines the spatial patterns of public responses towards the government-led urban heritage conservation projects in the historic city centre of Harbin, China, in sixteen months (2021–2022). The article concludes that social media plays an important role in accessing broader communities, monitoring people's preferences, and observing heritage attributes and values for inclusive urban heritage management.

Historical and future variation of soil organic carbon in China

Revealing historical changes in soil organic carbon (SOC) and exploring its future status are important for safeguarding soil health and food security, giving full play to the service function of soil ecosystems, and coping with climate change. However, there is still a gap in our understanding of the SOC stocks in China and their spatial patterns in response to future climate change. Therefore, we attempted to fill this knowledge gap using a large amount of soil observation data, digital soil mapping technology, and global circulation models from Coupled Model Inter-comparison Project phase 6 (CMIP6). In this study, a random forest model was selected to construct the spatial relationship between SOC in the top 0–20 cm (SOC020) and 0–100 cm (SOC0100) of the soil and 21 environmental factors. Spatiotemporal changes in SOC from 1980 to 2100 were revealed at a resolution of 1 km and five-year interval for three climate scenarios in CMIP6. The cross-validation results indicated acceptable predictions for both depths of SOC; however, relatively large prediction uncertainties were observed for SOC0100 in the Tibetan Plateau and northeastern China. The mean values of SOC020 and SOC0100 over the last four decades were 35.77 and 84.62 Tg, respectively, and showed carbon sinks at the national scale, with accumulation rates of 0.05 Pg yr-1 and 0.036 Pg y-1 for the two depths. Compared with historical values (1980–2020), SOC will fluctuate significantly in the future under different climate scenarios. Among them, SOC showed a slow increasing trend at both depths under the SSP1-1.9 low emission scenario, while SOC presented a decreasing trend under the SSP2-4.5 and SSP5-8.5 medium–high emission scenarios. In particular, in most of China under the SSP2-4.5 scenario, SOC0100 presented a larger likelihood of being a carbon source. This study provides a reference for exploring the response of soil carbon pools to climate change and evaluating the effectiveness of land management and ecological protection.

Mechanisms of hydrological responses to volcanic eruptions in the Asian monsoon and westerlies-dominated subregions

Abstract. Explosive volcanic eruptions affect surface climate, especially in monsoon regions, but responses vary in different regions and to volcanic aerosol injection (VAI) in different hemispheres. Here, we use six ensemble members from the last-millennium experiment of the Coupled Model Intercomparison Project Phase 5 to investigate the mechanisms of regional hydrological responses to different hemispheric VAIs in the Asian monsoon region (AMR). Northern hemispheric VAI (NHVAI) leads to an intensified aridity over the AMR after northern hemispheric VAI (NHVAI); spatially, a distinct inverse response pattern to the climatological conditions emerges, with an intensified aridity in the relatively wettest area (RWA) but a weakened aridity in the relatively driest area (RDA) of the AMR. Southern hemispheric VAI (SHVAI) shows a weakened aridity over the AMR, but the spatial response pattern is not that clear due to small aerosol magnitude. The mechanism of the hydrological impact relates to the indirect change of atmospheric circulation due to the direct radiative effect of volcanic aerosols. The decreased thermal contrast between the land and the ocean after NHVAI results in a weakened East Asian summer monsoon and South Asian summer monsoon. This changes the moisture transport and cloud formation in the monsoon and westerlies-dominated subregions. The subsequent radiative effect and physical feedbacks of local clouds lead to different hydrological effects in different areas. Results here indicate that future volcanic eruptions may temporarily alleviate the uneven distribution of precipitation in the AMR, which should be considered in the near-term climate predictions and future strategies of local adaptation to global warming. The local hydrological responses and mechanisms found here can also provide a reference for stratospheric aerosol engineering.