Changes In Storage Research Articles

A Simulated Assessment of Land Use and Carbon Storage Changes in the Yanqi Basin under Different Development Scenarios

A Simulated Assessment of Land Use and Carbon Storage Changes in the Yanqi Basin under Different Development Scenarios

Monitoring of Extreme Drought in the Yangtze River Basin in 2022 Based on Multi-Source Remote Sensing Data

The Yangtze River Basin experienced a once-in-a-century extreme drought in 2022 due to extreme weather, which had a serious impact on the local agricultural production and ecological environment. In order to investigate the spatial distribution and occurrence of the extreme drought events, this study used multi-source remote sensing data to monitor the extreme drought events in the Yangtze River Basin in 2022. In this study, the gravity satellite data product CSR_Mascon was used to calculate the GRACE Drought Intensity Index (GRACE-DSI), which was analyzed and compared with the commonly used meteorological drought indices, relative soil humidity, and soil water content data. The results show that (1) terrestrial water storage change data can well reflect the change in water storage in the Yangtze River Basin. Throughout the year, the average change in terrestrial water storage in the Yangtze River Basin from January to June is higher than the average value of 33.47 mm, and the average from July to December is lower than the average value of 48.17 mm; (2) the GRACE-DSI responded well to the intensity and spatial distribution of drought events in the Yangtze River Basin region in 2022. From the point of view of drought area, the Yangtze River Basin showed a trend of extreme drought increasing first, and then decreasing in the area of different levels of drought, and the range of drought reached a maximum in September with a drought area of 175.87 km2, which accounted for 97.71 per cent of the total area; at the same time, the area of extreme drought was the largest, with an area of 85.69 km2; (3) the spatial and temporal variations of the GRACE-DSI and commonly used meteorological drought indices were well correlated, with correlation coefficients above 0.750, among which the correlation coefficient of the SPEI-3 was higher at 0.937; (4) the soil moisture and soil relative humidity products from the CLDAS, combined with soil moisture products from the GLDAS, reflect the starting and ending times of extreme drought events in the Yangtze River Basin in 2022 well, using the information from the actual stations. In conclusion, gravity satellite data, analyzed in synergy with data from multiple sources, help decision makers to better understand and respond to drought.

Significant Local Sea Level Variations Caused by Continental Hydrology Signals

AbstractSpace gravity missions have enabled the quantification of the mass component of sea‐level rise over the past two decades. Barystatic sea‐level rise is predominantly driven by melting polar ice sheets and mountain glaciers. However, continental hydrological processes also contribute to global sea level change at significant magnitudes. We show that for most coastal areas in low‐to‐mid latitudes, up to half of manometric sea‐level rise is due to changes in water storage in ice‐free continental regions. At other locations the direct attraction effect of anthropogenic pumping of groundwater over the duration of the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow‐On (GRACE‐FO) mission offsets sea‐level rise from ice sheet and glacier melt. If these trends in continental hydrological storage were to slow or stop, these regions would experience greatly accelerated sea‐level rise, posing a risk to coastal settlements and infrastructure, however, for most coastal communities current rates of sea‐level rise would be significantly reduced.

A landscape index for indicating the spatio-temporal dynamics of carbon storage in an opencast coal mine

Coal is China’s main resource, with open-pit mining accounting for a significant portion of global production. However, this activity, including mining and ecological restoration, can have a definite impact on ecosystem carbon storage and its distribution; its associated factors are also unclear. In this paper, we quantify the carbon storage changes in Haerwusu coal mine, a typical large-scale coal mine in China, based on land use/land cover (LULC) characteristics, and analyze the impact factors of carbon density from 2007 to 2022 by integrating the InVEST model with the landscape ecological function contribution ratio and multiple regression model. The results are as follows. (1) Carbon storage decreased from 159.95 × 104 to 147.51 × 104 from 2007 to 2017 and then increased to 151.91 × 104 to 2022. (2) The degree of coordination between carbon storage forest and grassland area landscape pattern coupling ranged from 0.887 to 0.867 from 2007 to 2022, with the lowest point at 0.720 in 2012. (3) Carbon storage was significantly related to vegetation indices, temperature, and elevation, and these factors can explain 37.5% of the carbon storage spatial variability; stepwise regression analysis showed that the integration of landscape patterns, such as Shannon’s diversity index (SHEI) and the aggregation index (AI), could improve the explanation by 1.4%. (4) Based on the analysis of the landscape ecological function contribution ratio, the carbon storage-sensitive areas can be classified into three levels: extremely sensitive areas ranging 0 to 4 km from the mine, sensitive areas ranging 4 to 8 km, and insensitive areas ranging beyond 8 km. This study proposes a strategy for analyzing changes of carbon storage in coal mines, highlights the important role of landscape patterns in influencing carbon storage, and provides a reliable reference support for the ecological management of coal mines.

Evaluating the application feasibility of thyme oil nanoemulsion coating for extending the shelf life of papaya (Carica papaya cv. Tainung No. 2) with postharvest physiology and quality parameters

Papaya (Carica papaya L.) is a typical climacteric fruit with a brief shelf life due to the rapid degradation of quality during post-ripening, necessitating appropriate postharvest management to address this challenge. This study aimed to investigate the characteristics of thyme oil nanoemulsion (TO-NE) coating and utilize its benefits for preserving papaya. This study also investigated the physiological properties and quality changes of papaya storage at 20 ℃ and, in parallel, examined the effects of TO-NE coating to mitigate microbial infection of papaya during storage. The postharvest papaya was soaked in different concentrations (0.1, 0.25, and 0.5 mg/g) of TO-NE for coating. At the same time, the decay loss rate and effective shelf life were also evaluated. This study revealed that polygalacturonase (PG) and pectinesterase (PME) activities were inhibited during the storage of papaya treated with 0.25 mg/g TO-NE coated compared to the control group. This resulted in the preservation of the firmness of papaya fruits, in addition to a higher ascorbic acid content, delayed total soluble solids (TSS) accumulation, and total chlorophyll content (TCC) degradation, with a lagging color change for two days. The respiration rate and ethylene production were suppressed, while the 0.25 mg/g TO-NE coated group at day 14 (ethylene peak) were 63.2 mg CO2 kg−1 h−1 and 7.3 µL kg−1 h−1, lower than control. The 0.25 mg/g TO-NE coating treatment significantly reduced the decay rate for 10 days of storage, preserving their appearance and facilitating ripening. This is a viable option for extending Tainung No.2 papaya shelf life.Graphical

Mechanism of Vegetation Greenness Change and Its Correlation with Terrestrial Water Storage in the Tarim River Basin

The response of dryland vegetation to climate change is particularly sensitive in the context of global climate change. This paper analyzes the characteristics of spatial and temporal dynamics of vegetation cover in the Tarim River Basin, China, and its driving factors in order to investigate the response of vegetation growth to water storage changes in the basin. The Enhanced Vegetation Index (EVI), the GRACE gravity satellite, and meteorological data from 2002 to 2022 are used to decipher the characteristics of the response of water storage changes to vegetation changes, which is of great significance to the realization of regional ecological development and sustainable development. The results of the study show the following: (1) The vegetation in the Tarim River Basin has an overall increasing trend, which is mainly distributed in the Aksu Basin and the Weigangkuche River Basin and is spatially distributed in the form of a ring. (2) Vegetation distribution greatly improved during the 20-year study period, dominated by high-cover vegetation, with a change rate of 200.36%. Additionally, vegetation changes are centered on the watersheds and expand to the surrounding area, with a clear increase in vegetation in the Kumukuri Basin. Areas with a vegetation Hurst index of <0.5 account for 63.27% of the study area, and the areas with a continuous decrease were mainly located in the outer contour area of the Tarim River and Kumu Kuri Basins. (3) There are obvious spatial differences in the correlation between EVI and temperature and precipitation elements. The proportion of areas with positive correlation with temperature within the study area is 64.67%. EVI tends to be consistent with the direction of migration of the center of gravity of the population and GDP, and the areas with positive correlation between vegetation and terrestrial water reserves are mainly distributed in the northern slopes of the Kunlun Mountains, with an area proportion of about 50.513%. The Kumukuli Basin also shows significantly positive correlation.

Natural pre-treatment in raisins production: Effects on quality during storage

BRS Vitoria raisins were produced with a pre-treatment using a natural surfactant, i.e., extra-virgin olive oil (EVOO), to (i) better elucidate its action on the grape surface using scanning electron microscopy; (ii) evaluate its influence on the oleanolic and ursolic acid content of raisins through HPLC-DAD; (iii) assess raisins characteristics during 180-day storage at different temperatures by using physicochemical and microbiological analyses with multivariate-based chemometric methods (MASLT). Grapes which presented adequate physicochemical characteristics and high concentration of anthocyanins originated raisins similar to those reported in the literature. The pre-treatment accelerated the dehydration process (about 26%) mainly because of the non-uniform redistribution of the surface waxy components accompanied by the formation of microholes and cracks. The small amount of EVOO used did not affect the oleanolic acid content in raisins, yet this compound proved to resist drying, which means that there is no loss of wax during the pre-treatment. For both untreated (RW) and pre-treated raisins (RP), the main changes triggered over time were not related to microbiological characteristics. Most of the changes appeared to occur right during drying and not during storage for RW, whereas for RP the physicochemical characteristics that mostly correlated with the storage changes were total monomeric anthocyanins, total acidity, and total sugars; also, they tended to reach an equilibrium and equaled RW at the end of 180 days, especially at 35 °C. These parameters proved to be the main characteristics related to the changes triggered in raisins. For both raisins, sugar crystals were formed in the flesh, but they were not visible to the naked eye or perceived by consumers. The results show that it is highly desirable to have a high-quality product at the beginning of storage, which was possible thanks to the EVOO pre-treatment used.

Temporal and spatial variations of terrestrial water storage in the northeastern Tibetan Plateau retrieved by GNSS observations

The variation of solid Earth's hydrologic loading could cause the elastic vertical deformation of the crust, and the Global Navigation Satellite System (GNSS) could effectively monitor the vertical displacement of surface loads. However, the widely used Green's function method does not work well in areas where GNSS sites are sparse. Here, the vertical displacement time series of GNSS stations and the Slepian basis function method have been applied to convert displacement signals into spatial spectrum signals. The elastic mass load theory is used to study the changes in terrestrial water storage on the Northeastern Tibetan Plateau (NETP). The temporal and spatial characteristics of seasonal water changes are well-represented by the GNSS, the Gravity Recovery and Climate Experiment (GRACE), and the Global Land Data Assimilation System (GLDAS). Several data points suggest that the change in water storage shows a gradual increase from the northeast to the southwest. The greatest annual amplitude of water storage retrieved by GNSS is ∼159 mm, which is greater than the ∼47 mm and ∼44 mm obtained by GRACE and GLDAS. These results demonstrate that GNSS is capable of capturing small-scale hydrological changes in this region, whereas GRACE and GLDAS data tend to underestimate seasonal variations in water storage. We also used GNSS to describe the hydrological drought conditions in NETP, showing that GNSS could be used as an independent method to characterize hydrological drought events. The findings suggest it could observe water storage with high spatial and temporal resolution and aid in comprehending regional hydrological trends with a sparse GNSS station network.

Significant contribution of the Tianshan lakes to their water storage and water resources

Study regionThe Tianshan region Study focusThe Tianshan region possesses a complex landscape with lakes, and changes in the water storage of these lakes serve as a crucial indicator of climate change. They also represent a significant water resource for the local area, profoundly impacting water resource allocation and playing a pivotal role in understanding the mass balance in the Tianshan region. Nevertheless, there is still a lack of systematic research on the Tianshan lake group. New hydrological insights for the regionThe results reveal that the total lake water storage is exhibiting an increasing trend (0.73±0.10 Gt/a). The Tianshan region experienced two periods of mass anomalies in 2010 and 2016, which were reflected not only in the changes of lake water storage but also in soil moisture, snow water, and even Global Navigation Satellite System (GNSS) displacement fields. These two mass anomalies were closely related to abnormal precipitation resulting from El Niño events (r=0.55, p<0.01). During these two mass anomaly periods, the regional total mass increased by 65.73 Gt and 67.35 Gt. Compared with their contributions to the mass (22% and 14%), the variations in lake area were remarkably slight (0.01% and 0.014%). This study contributes to understanding the sensitivity of lakes to climate responses and underscores the necessity of lake research for water resource management in complex surface environments.

Spatio-Temporal Analysis of Carbon Storage in Urban Areas After Wildfires: The Case of Marmaris Fire

Cities and urban areas are the primary source of CO2 worldwide by using around 70% of global energy and emitting more than 71% of CO2. Urban vegetation, referring to all trees and shrubs, are important components of urban environments. They provide many ecosystem services to human beings both directly and indirectly. Especially, they play a key role in reducing carbon emissions in urban areas by storing and capturing the carbon. However, recently, an increase in the number and intensity of wildfires that occur within urban areas has been observed. It resulted in losing stored carbon, releasing GHG to the atmosphere. Hence, quantifying above-ground carbon stored by urban trees and its distribution is essential to better understanding urban vegetation's role in urban environments and to better urban vegetation management. This study aimed to examine how forest fire affects the amount and distribution of stored carbon in the urban environment for the case of the Marmaris fire in the Summer of 2021 in Türkiye. For the study, urban forest carbon storage maps were generated before and after the Marmaris forest fire using remote sensing-based methodology with freely available remote sensing (RS) data. The results indicated that using the existing methodology could be rapid and cost-effective in monitoring the carbon storage change after an anthropogenic and natural disaster. However, for precise and reliable estimation of total carbon storage and the change in total urban carbon storage, the methodology needs to be developed at a local scale using field sampling along with RS data.

Changes in terrestrial water storage in the Three-North region of China over 2003–2021: Assessing the roles of climate and vegetation restoration

Large-scale vegetation restoration has markedly enhanced ecosystem services in the Three-North (TN) region, concurrently exacerbating the pre-existing water resource crisis stemming from climate change in this arid domain. However, the specific contributions of climate and vegetation changes to the evolution of water resources in the TN region have yet to be elucidated. This study leverages data from the Gravity Recovery and Climate Experiment (GRACE) and its Follow-on mission (GRACE-FO), specifically the terrestrial water storage anomaly (TWSA) from 2003 to 2021. We identify two TWSA rising (TWSA_rⅠ and TWSA_rⅡ) and two declining (TWSA_dⅠ and TWSA_dⅡ) hotspots in the TN region. By exploring the relative importance of climate drivers and vegetation dynamics in influencing the temporal dynamics of TWSA, we found that vegetation restoration assumes a more pivotal role than climate factors in 45.2% of the total area within the identified hotspots, predominantly evident in TWSA declining hotspots. The heightened TWSA in TWSA_rⅠ and TWSA_rⅡ primarily stems from precipitation recharge, with precipitation-dominated areas constituting 19.3% of the area within the identified hotspots. Potential evapotranspiration dominates TWSA changes in only 4.6% of the region within the identified hotspots, primarily scattered in TWSA_dⅠ and TWSA_dⅡ. Furthermore, a comparative assessment of soil moisture and groundwater responses to environmental factors indicates that water storage at shallower layers is more responsive to climate factors, while the impacts of vegetation changes on TWSA are more discernibly reflected in water storage at deeper layers. These findings furnish scientific guidance for future ecological restoration planning and sustainable water resources management.

The effects of damming and dam regulation on a river–lake-aquifer system: 3D groundwater flow modeling of Poyang Lake (China)

Large numbers of dams are planned or constructed for hydroelectric power production, water supply, and flood control in many rivers around the world. While the social and environmental impacts of dams are now well-understood, there is little knowledge about the effects of dams on groundwater-surface water interactions in a complex lake–river-aquifer system. This study adopts a three-dimensional groundwater numerical model to quantify the potential impacts of dam construction, on regional groundwater flow system, exemplified by the proposed Poyang Lake Hydraulic Dam (PLHD) in China. Once implemented, the PLHD will regulate lake levels, artificially controlling the lake inundation area during the recession season (September-October) and the dry season (November-December). Modeling results indicated that the increase in lake infiltration induced by PLHD regulation would alter the regional water exchange pattern. The PLHD regulation will likely enhance the groundwater storage by 20.44 % in the general dry year (i.e., 2018), alleviating 78.1 % of the groundwater deficit in the extreme dry year (i.e., 2019). Additionally, the response of groundwater dynamics to the PLHD regulation exhibits significant spatial differences between the upstream and downstream areas of the dam, primarily depending on topographical changes. Overall, the PLHD regulation is most likely to impact groundwater levels across an area of approximately 5,700 km2, and the associated groundwater storage is anticipated to reach a stable state, under future long-term regulation. Our findings may guide policy-makers wishing to develop more suitable PLHD scheduling plans and floodplain protection strategies by providing reliable information regarding groundwater storage change and ecosystem succession.

The Nutritional Year-Cycle of Italian Honey Bees (Apis mellifera ligustica) in a Southern Temperate Climate

Nutrition is a key aspect influencing honey bee health and overwintering. Since honey bee seasonality in southern temperate climates represents a significant research gap, this study conducted long-term monitoring of honey bees in the Mediterranean (Sassari, Italy). Specifically, individual weight, fat body, and size measurements (head, thorax, abdomen, and total body) were recorded monthly so to detect changes in the nutrient storage of worker bees during an annual cycle. Data were analysed according to sampling date, climate (temperature, precipitation, and daylength), and flower diversity and were conducted for nurse and forager bees separately. The nutritional honey bee year-cycle generally followed the nectar flow and showed two critical timepoints: summer and winter dearth. A short cessation of activities in late fall/early winter coupled with an increase in nutrient storage indicated the presence of winter bees. Precipitation was found to play an important role in honey bee nutrition in the study area through its impacts on colony demography and plants in particular illustrating how climate change could pose a threat to European honey bee populations in the future. These results provide valuable insights into the nutritional dynamics of Apis mellifera ligustica in the Mediterranean that could support management decisions to improve overwintering success and prevent unnecessary colony losses.

Analyzing groundwater storage anomalies in data‐scarce areas of Ethiopia's Rift Valley Basin using artificial neural network

AbstractGroundwater storage anomalies (GWSA) study requires the use of hydro‐climatic models coupled with Gravity Recovery and Climate Experiment climate (GRACE) and GRACE Follow‐On (GRACE‐FO) Terrestrial Water Storage experiments. Understanding groundwater storage anomalies in the research area is difficult due to the restricted hydro‐meteorological data availability, especially, groundwater levels, changes in groundwater storage, and budgetary and technical constraints. No such investigation of GWS anomalies prior to this study in this Basin was conducted. The research focuses on GWSA investigations in the basin employing Global Land Data Assimilation Systems and Artificial Neural Networks‐Back Propagation Algorithm techniques are required. The ultimate objective of this study was to reduce the GRACE GWS from 1° to 0.25° and close the discontinuity between GRACE/GRACE‐FO observations. The results illustrated that GRACE/GRACE‐FO GWS throughout the basin were overall declining. The GWS anomaly significantly decreased between 2011 and 2013, with the highest monthly depletion in March 2011 (−158 mm). In contrast, from mid‐June to mid‐October, the maximum positive value varied from 20.80 mm in the southernmost basin to 39.49 mm in the central‐southeastern basin. The basin's eastern, central‐southeastern, northern, and southern areas displayed positive monthly GWS trends. The entire dry season has been influenced by negative anomalies. Hence, the identification of GWS variations and a comprehensive understanding of their effects provided valuable scientific insights. Identifying and analyzing anomalies in groundwater storage (GWS) can provide valuable information. This data can be efficiently used to develop appropriate regulatory frameworks, which may contribute to the long‐term viability of the availability of groundwater.

Disaggregating National Statistical Data to Assess the Sub-National SDG 6.4.2 Water Stress Indicator by Integrating Satellite Observations and Model Data

Ensuring the sustainable management of water and sanitation for all is the primary goal of Sustainable Development Goal 6 (SDG 6). SDG indicator 6.4.2 (level of water stress) is critical for monitoring the progress toward SDG 6. The assessment of the SDG indicator 6.4.2 is currently based on statistical data at the national scale, i.e., one value for one country, which cannot reflect spatial variability in water stress in a country. The lack of data at sub-national scales limits the assessment of water stress in sub-national regions. This study developed a method of disaggregating national statistical renewable water resources (TRWR) and freshwater withdrawals (TFWW) to estimate the SDG 6.4.2 water stress indicator at a sub-national scale by combining satellite remote sensing data and model simulated data. Remote sensing (RS)-based precipitation (P); the difference between precipitation and evapotranspiration (P-ET); and the difference between precipitation, evapotranspiration, terrestrial water storage change (P-ET-dS), and model-simulated naturized runoff and withdrawal water use were used as spatial and temporal surrogates to disaggregate the national-scale statistics of TRWR and TFWW to the grid scale. Gridded TRWR and TFWW can be used to calculate the water stress of any interest regions. Disaggregated TRWR, TFWW, and water stress estimation were validated at three different spatial scales, from major river basins and provinces to prefectures in China, by comparing the corresponding statistical data. The results show that the disaggregation for TRWR is generally better than for TFWW, and the overall accuracy for water stress estimation can reach up to 91%. The temporal evolution of disaggregated variables also showed good consistency with statistical time series data. The RS-based P-ET and P-ET-dS have great potential for disaggregating TRWR at different spatiotemporal scales, with no obvious differences with the results using the model simulation as a surrogate for the disaggregation of SDG indicator 6.4.2. The disaggregation accuracy can be further improved when the sub-regional statistical data of TRWR and TFWW are applied to the disaggregation approach.

Tracking annual dynamics of carbon storage of salt marsh plants in the Yellow River Delta national nature reserve of china based on sentinel-2 imagery during 2017–2022

Coastal salt marshes play a key role in coastal carbon sequestration. Understanding the spatial distribution and annual changes of carbon storage of salt marsh plants at a local scale is helpful for accurate protection and restoration. However, the annual carbon storage of salt marsh plants has not yet been obtained in the Yellow River Delta National Nature Reserve (YRDNNR), China. Here, we developed a fast and reliable method to produce an annual map of carbon storage of herbaceous salt marsh plants from 2017 to 2022 based on multi-year in situ data and 10-meter resolution Sentinel-2 images in YRDNNR. That is, a deep belief network based on conjugate gradient (CGDBN) pixel-level classification, a generative adversarial network with a constrained factor (GAN-CF) measured sample expansion and multiple linear regression (MLR) quantitative inversion algorithm is used. The results showed that: (1) The carbon storage of herbaceous salt marsh plants in the YRDNNR increased in 2017–2018 and 2019–2021, with an average carbon storage dynamic of 4.53–8.39 Mg/ha. (2) In 2021, the area of salt marsh vegetation increased significantly by 20 % compared to 2017. Although its area decreased sharply due to the removal of invasive species (S. alterniflora) in 2022, the carbon storage per unit area of salt marsh plants remained at 7.77 Mg/ha. (3) The carbon storage of salt marsh vegetation showed a gradient change along the community succession from land to sea. Estimating annual carbon storage of salt marsh plants could provide basic data for recognizing the ‘blue carbon’ contribution of coastal plants and managing the coastal salt marsh ecosystem in Yellow River Delta.

Early changes in carbon uptake and partitioning moderate belowground carbon storage in a perennial grain

There is increasing interest in perennial crops to build soil carbon (C), but the mechanisms underlying soil C accrual in perennial croplands remain unclear, especially over time in the first years of perennial crop growth. To address this gap, research is needed that directly tracks intra-annual C fluxes through crop-microbial-soil pools, evaluating the capacity of perennial crops to build soil C over intra-decadal time periods. We conducted a 13C isotope-tracer study to compare within-season C uptake and crop-microbial-soil C partitioning patterns between 1-year-old (IWG-1) and 2-year-old (IWG-2) stands of a novel perennial grain crop, intermediate wheatgrass (IWG; Thinopyrum intermedium (Host) Barkworth and Dewey). We compared these to a common annual grain crop, spring wheat (Triticum aestivum L.). Crop shoots, roots, soil, and soil respired-C were sampled ten times over a 90-day chase period. We also measured the incorporation of recently assimilated 13C into soil microbial biomass (13C PLFA) and functional groups over the first 7 days post-label application. Overall, IWG-1 assimilated almost 1670 mg 13C m−2 during the study period, nearly twice that of IWG-2 or wheat, but neither IWG system retained significant amounts of new C in soil. Rather, a higher proportion of assimilated new C was retained in IWG-1 in root tissues (14%) and arbuscular mycorrhizal fungi when compared to other cropping systems, while IWG-2 retained almost 50% of total assimilated C in aboveground crop tissues. We expect the shift from new C retention in belowground root-mycorrhizal networks to aboveground tissues is associated with a shift from an acquisitive to conservative growth strategy that occurs between the first and second IWG production years. The observed shift in C partitioning patterns and potential change in growth strategy limited the allocation and retention of new C in soil as IWG aged, adding valuable context to our understanding of why perennial grain crop establishment seldom leads to significant carbon gains in the first several years following establishment.

Rock moisture reinforces belowground water storage under different precipitation scenarios and vegetation coverage

Rock moisture is rarely deliberated but crucial for hydrologic regulation in semiarid loess hilly regions. In this study, using in-situ monitoring observation and simulation, soil and rock moisture spatiotemporal variations under planting alfalfa and caragana were analyzed and sketched, and the water storage contributions by weathered bedrock layers (WBLs) under different rainwater scenarios were then simulated and estimated. The results showed that WBLs had apparent spatiotemporal changes in water distribution and storage with rainfall events. Under water scarcity scenarios, WBLs increased the variabilities of water storage, with an average increase of 89.9 % in alfalfa and 14.2 % in caragana, providing wider water supply boundaries for vegetation. However, higher volumetric water content was presented under relatively abundant water scenarios. The average soil water content was 0.08 cm3 cm−3 in alfalfa and 0.09 cm3 cm−3 in caragana, while the average rock water content was 0.12 cm3 cm−3 in alfalfa and 0.13 cm3 cm−3 in caragana. Profile water consumption goes to surface soil evaporation and plant transpiration over an entire growing season, while extrawater would be stored in WBLs to maintain vegetation growth during the water-scarce seasons. Moreover, water storage had a positive linear relationship with the thickness of WBLs. Rock water storage increased by 6.9 % in alfalfa and 3.7 % in caragana after adding 20 cm WBLs, while it increased by 23.6 % in alfalfa and 9.9 % in caragana after adding 50 cm WBLs. Furthermore, various exogenous rainwater simulations showed that differences in water storage were significantly increased with WBLs thickness. This study would provide new insights into the deep-rooted plant distribution planning in semiarid loess hilly regions, and could also be helpful for the rational water resources utilization and management in shallow soil areas.

Statistical downscaling of GRACE terrestrial water storage changes based on the Australian Water Outlook model

The coarse spatial resolution of the Gravity Recovery and Climate Experiment (GRACE) dataset has limited its application in local water resource management and accounting. Despite efforts to improve GRACE spatial resolution, achieving high resolution downscaled grids that correspond to local hydrological behaviour and patterns is still limited. To overcome this issue, we propose a novel statistical downscaling approach to improve the spatial resolution of GRACE-terrestrial water storage changes (ΔTWS) using precipitation, evapotranspiration (ET), and runoff data from the Australian Water Outlook. These water budget components drive changes in the GRACE water column in much of the global land area. Here, the GRACE dataset is downscaled from the original resolution of 1.0° × 1.0° to 0.05° × 0.05° over a large hydro-geologic basin in northern Australia (the Cambrian Limestone Aquifer—CLA), capturing sub- grid heterogeneity in ΔTWS of the region. The downscaled results are validated using data from 12 in-situ groundwater monitoring stations and water budget estimates of the CLA’s land water storage changes from April 2002 to June 2017. The change in water storage over time (ds/dt) estimated from the water budget model was weakly correlated (r = 0.34) with the downscaled GRACE ΔTWS. The weak relationship was attributed to the possible uncertainties inherent in the ET datasets used in the water budget, particularly during the summer months. Our proposed methodology provides an opportunity to improve freshwater reporting using GRACE and enhances the feasibility of downscaling efforts for other hydrological data to strengthen local-scale applications.

Comparison of groundwater storage changes over losing and gaining aquifers of China using GRACE satellites, modeling and in-situ observations

Groundwater depletion in intensively exploited aquifers of China has been widely recognized, whereas an overall examination of groundwater storage (GWS) changes over major aquifers remains challenging due to limited data and notable uncertainties. Here, we present a study to explore GWS changes over eighteen major aquifers covering an area of 1,680,000 km2 in China using data obtained from the Gravity Recovery and Climate Experiments (GRACE), global models, and in-situ groundwater level observations. The analysis aims to reveal the discrepancy in annual trends, amplitudes, and phases associated with GWS changes among different aquifers. It is found that GWS changes in the studied aquifers represent a spatial pattern of ‘Wet-gets-more, Dry-gets-less’. An overall decreasing trend of −4.65 ± 0.34 km3/yr is observed by GRACE from 2005 to 2016, consisting of a significant (p < 0.05) increase of 47.28 ± 3.48 km3 in 7 aquifers and decrease of 103.56 ± 2.4 km3 (∼2.6 times the full storage capacity of the Three Gorges Reservoir) in 10 aquifers summed over the 12 years. The annual GWS normally reaches a peak in late July with an area-weighted average annual amplitude of 19 mm, showing notable discrepancy in phases and amplitudes between the losing aquifers (12 mm in middle August) in northern China and gaining aquifers (28 mm in early July) mostly in southern China. GRACE estimates are generally comparable, but can be notably different, with the results obtained from model simulations and in-situ observations at aquifer scale, with the area-weighted average correlation coefficients of 0.6 and 0.5, respectively. This study highlights different GWS changes of losing and gaining aquifers in response to coupled impacts of hydrogeology, climate and human interventions, and calls for divergent adaptions in regional groundwater management.