Terrestrial water storage (TWS) is a critical component for sustainable societal development and ecosystem cycles. The Gravity Recovery and Climate Experiment satellites have tracked changes in ...global TWS under the combined effects of various factors with unprecedented accuracy since 2002. In this study, we separate the trends in TWS driven by precipitation and non‐precipitation factors for the Chinese mainland from 2003 to 2016 based on the statistical reconstruction method and linear regression and analyze the driving mechanisms combining with multi‐source data. The results show that: (a) during the study period, TWS shows different degrees of increase in most of the Yangtze River basin, the northern part of the Tibetan Plateau, and part of the Heilongjiang Province, while TWS shows a significant decrease in the Tien Shan Mountains, the southeastern part of the Tibetan Plateau, and the North China Plain; (b) precipitation is one of the dominant factors leading to the rise of TWS, and the construction of reservoirs and dams also contributes. In contrast, anthropogenic activities (agricultural irrigation, industrial water use, etc.) and accelerated glacial melting due to global warming are the dominant factors in the decline of water storage; (c) the contribution of long‐term precipitation change to water storage is significantly larger in the northern China region (north of the 800 mm isopleth). This study provides a feasible method for quantifying the contribution of precipitation and non‐precipitation factors to TWS, which is meaningful for understanding the impact of climate change and anthropogenic factors on water resources.
Plain Language Summary
Water scarcity is a global crisis for social development in the present and future. As the world's most populous country, China's per capita freshwater resources are far below the global average, making the imbalance between water supply and demand in China even more serious. The study of water storage changes contributes to understanding freshwater resources in China. Here, the precipitation‐ and non‐precipitation‐ driven water storage changes in China are separated based on the statistical reconstruction method and long‐term precipitation data. In addition, satellite gravity, model simulations, and in‐situ data are combined to analyze the driving mechanism in regions that experienced significant changes in water storage during the past decades. Human activities and glacier melting are the dominant factors leading to the water storage deficit. Both precipitation and dam construction contribute to the increase in water storage. This study would provide valuable information for the rational allocation of water resources and coordinated development of the economy and ecology.
Key Points
Terrestrial water storage (TWS) trends induced by long‐term precipitation change, precipitation variability, and non‐precipitation factors are separated in China
The TP‐TWS factor is proposed to characterize the impact of long‐term precipitation trends on the TWS trends
The TWS changes in typical regions are rationalized from the perspective of precipitation and non‐precipitation factors
The terrestrial water storage anomaly (TWSA) observed by the Gravity Recovery and Climate Experiment (GRACE) satellite and its successor GRACE Follow-On (GRACE-FO) provides a new means for monitoring ...floods. However, due to the coarse temporal resolution of GRACE/GRACE-FO, the understanding of flood occurrence mechanisms and the monitoring of short-term floods are limited. This study utilizes a statistical model to reconstruct daily TWS by combining monthly GRACE observations with daily temperature and precipitation data. The reconstructed daily TWSA is utilized to monitor the catastrophic flood event that occurred in the middle and lower reaches of the Yangtze River basin in 2020. Furthermore, the study compares the reconstructed daily TWSA with the vertical displacements of eight Global Navigation Satellite System (GNSS) stations at grid scale. A modified wetness index (MWI) and a normalized daily flood potential index (NDFPI) are introduced and compared with in situ daily streamflow to assess their potential for flood monitoring and early warning. The results show that terrestrial water storage (TWS) in the study area increases from early June, reaching a peak on 19 July, and then receding till September. The reconstructed TWSA better captures the changes in water storage on a daily scale compared to monthly GRACE data. The MWI and NDFPI based on the reconstructed daily TWSA both exceed the 90th percentile 7 days earlier than the in situ streamflow, demonstrating their potential for daily flood monitoring. Collectively, these findings suggest that the reconstructed TWSA can serve as an effective tool for flood monitoring and early warning.
•A daily terrestrial water storage anomaly reconstruction framework is proposed based on the precipitation reconstruction method.•Evapotranspiration is calculated for nine exorheic basins in China ...from the water balance equation based on three different terrestrial water storage change estimates.•The reconstruction method significantly reduces the frequency and magnitude of negative evapotranspiration values.•Uncertainties derived from the three-cornered hat method indicate that the evapotranspiration derived from the reconstruction method is superior to the other two terrestrial water storage change estimates.
Evapotranspiration (ET) is a critical component of the global water cycle, but basin-scale ET is often difficult to accurately estimate. Due to the limitations of the temporal resolution of the Gravity Recovery and Climate Experiment (GRACE) satellites and coverage period, daily or monthly terrestrial water storage (TWS) changes at basin scale are hard to obtain, which limits the application of water balance in ET estimation. To surmount this limitation, we established a daily TWS anomaly reconstruction framework. Based on this framework, the reconstructed daily TWS anomalies (TWSAs) were used for the first time to estimate the basin-scale ET in nine exorheic basins of China. Furthermore, we combined four commonly used ET models and TWS change (TWSC) derived by two different TWSA interpolation methods to evaluate the uncertainty of the different methodologies using the three-cornered hat (TCH) approach. The results show that: (i) the number of negative values of ET from the two TWSA interpolation methods is close to each other. For the reconstruction method, the number of negative values is reduced by about 70% relative to interpolation methods, which significantly improves the quality of the ET estimates; and (ii) among the seven sequences involved in the TCH calculation, the two TWSA interpolation methods show the largest uncertainty, while the reconstruction method has similar or optimal performance to the four ET models in all the basins except the Huaihe River Basin and the Minjiang River Basin. The results of this study demonstrate the superiority of derived TWSC based on the reconstruction framework in basin-scale ET estimation, which has a great potential for the application in the quantitative evaluation of ET and further assessment of ET models.
•A significant water storage loss of −158 ± 22 km3 occurred in August 2022 concerning July 2022 in the Yangtze River Basin.•The precipitation deficit and prolonged high temperature caused this ...extreme drought.•The hydrological drought identified by gravity satellite responds fast to meteorological drought.
In 2022, the Yangtze River Basin (YRB) experienced its most extreme drought event since 1961. Conducting a comprehensive assessment of this severe drought is crucial for understanding the entire drought process. GRACE and GRACE-FO gravity satellites have the capability to monitor global mass transport, making them suitable for large-scale drought monitoring. In this study, we investigated the changes in water storage caused by the drought using GRACE/GRACE-FO data and multi-source observations. Our evaluation incorporated meteorological drought indices, including the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), to explore the drought propagation process. Additionally, we examined the effects of trends in terrestrial water storage in the YRB, resulting from reservoir impoundment and climatic factors, on the drought index calculation. The results indicate that the extreme drought in the YRB began in August 2022, resulting in a water storage loss of approximately −158 ± 22 km3 compared to July 2022. There was almost no delay in the response of soil moisture drought and hydrological drought to the meteorological drought at a monthly scale. This extreme drought had its most severe impact on the middle and lower reaches of the YRB, especially in the Dongting Lake Basin, where the GRACE drought index value remained below −2.5 until December 2022. This study demonstrates the significant water storage deficit during the extreme drought in the YRB in 2022, providing a comprehensive understanding of this historic drought.
Drought is a prolonged dry period in the natural climate cycle, and is one of the most costly weather events. The Gravity Recovery and Climate Experiment (GRACE) derived terrestrial water storage ...anomalies (TWSA) have been widely used to assess drought severity. However, the relatively short cover period of GRACE and GRACE Follow-On limit our knowledge about the characterization and evolution of drought over decades time scale. This study proposes a standardized GRACE reconstructed TWSA index (SGRTI) to assess the drought severity based on a statistical reconstruction method calibrated by GRACE observations. Results show that the SGRTI correlates well with 6-month scale SPI and SPEI, with correlation coefficients reaching 0.79 and 0.81 in the YRB from 1981 to 2019. Soil moisture can capture drought condition like the SGRTI, while cannot further reflect deeper water storage depletion. The SGRTI is also comparable to the SRI and in-situ water level. As a case study for the Yangtze River Basin, its three sub-basins experience more frequent droughts, shorter drought duration, and lower severity drought, as identified by SGRTI during 1992–2019 relative to 1963–1991. The presented SGRTI in this study can provide a valuable supplement to the drought index before the GRACE era.
Display omitted
•A long-term standardized GRACE reconstructed TWSA index (SGRTI) is proposed.•The SGRTI correlates well with 6-month scale SPI and SPEI in the Yangtze River Basin (YRB).•The three sub-basins in the YRB experience more frequent droughts and shorter drought duration from 1963 to 2019.
Abstract
Assessing changes in freshwater availability accurately is crucial for societal development. Previous studies have examined long‐term variations in basin‐scale terrestrial water storage ...(TWS) using Gravity Recovery and Climate Experiment (GRACE) mission data. However, different basins exhibit distinct spatial and temporal TWS variation patterns. To better interpret the TWS trends in each basin during the GRACE era (2003–2016), this study proposes a novel criterion based on a century‐long GRACE‐REC data set. This criterion assesses the trends in GRACE TWS (Trend
G
), precipitation‐induced trends (Trend
PI
), and non‐precipitation‐induced trends (Trend
NPI
) over the GRACE period. By calculating upper and lower bound values for long‐term climate‐driven TWS trends using GRACE‐REC data, an indicator is provided to evaluate the range of TWS trend variations in a basin under natural conditions. Results reveal that among the 266 global basins analyzed in this study, the trends (Trend
G
, Trend
PI
, or Trend
NPI
) in 115 basins exceed the maximum or minimum water storage trends associated with natural climate variability. This includes 20 large basins, 34 medium basins, and 61 small basins, indicating significant TWS changes during the GRACE period. Furthermore, we analyze the driving mechanisms of TWS trends in the 20 large basins using multi‐source data. The mechanisms identified through this method align well with both our analysis and previous studies, confirming the reliability of this approach for assessing TWS trends.
Plain Language Summary
Understanding changes in freshwater availability is crucial for the development of human societies. This study focuses on assessing long‐term changes in basin‐scale terrestrial water storage (TWS) using data from the Gravity Recovery and Climate Experiment (GRACE) mission. The objective of this research was to develop a new criterion to assess TWS trends in different basins during the GRACE era. We calculated the upper and lower bound values of long‐term climate‐driven TWS trends for a given length of time, analyzed the trends induced by precipitation and non‐precipitation factors, and examined the driving mechanisms behind TWS trends in selected basins. Among the 266 global basins analyzed, 115 basins showed TWS trends that exceeded the trend bounds under natural climate variability. This indicates significant changes in TWS during the GRACE period. Our analysis of driving mechanisms aligned well with previous studies, providing confidence in the reliability of our approach. Our study reveals significant changes in TWS in numerous basins worldwide, highlighting the importance of monitoring and managing water resources effectively.
Key Points
A novel criterion is proposed to interpret trends in Gravity Recovery and Climate Experiment (GRACE), precipitation‐induced, and non‐precipitation‐induced water storage
The upper and lower bounds of long‐term climate‐driven terrestrial water storage (TWS) trends are estimated based on one century‐long GRACE‐REC data
Significant non‐precipitation effects contribute to GRACE trends below the lower bounds of climate‐driven TWS trends in global basins
Information flow among auditory and language processing-related regions implicated in the pathophysiology of auditory verbal hallucinations（AVHs） in schizophrenia（SZ） remains unclear. In this study, ...we used stochastic dynamic causal modeling（s DCM） to quantify connections among the left dorsolateral prefrontal cortex（inner speech monitoring）, auditory cortex（auditory processing）, hippocampus（memory retrieval）, thalamus（information filtering）, and Broca＇s area（language production） in 17 first-episode drug-na？¨ve SZ patients with AVHs, 15 without AVHs, and 19 healthy controls using resting-state functional magnetic resonance imaging.Finally, we performed receiver operating characteristic（ROC） analysis and correlation analysis between image measures and symptoms. s DCM revealed an increasedsensitivity of auditory cortex to its thalamic afferents and a decrease in hippocampal sensitivity to auditory inputs in SZ patients with AVHs. The area under the ROC curve showed the diagnostic value of these two connections to distinguish SZ patients with AVHs from those without AVHs. Furthermore, we found a positive correlation between the strength of the connectivity from Broca＇s area to the auditory cortex and the severity of AVHs. These findings demonstrate, for the first time, augmented AVHspecific excitatory afferents from the thalamus to the auditory cortex in SZ patients, resulting in auditory perception without external auditory stimuli. Our results provide insights into the neural mechanisms underlying AVHs in SZ. This thalamic-auditory cortical-hippocampal dysconnectivity may also serve as a diagnostic biomarker of AVHs in SZ and a therapeutic target based on direct in vivo evidence.
Background： Brucella is a zoonotic Gram-negative pathogen that causes abortion and infertility in ruminants and humans. TLR4 is the receptor for LPS which can recognize Brucella and initiate ...antigen-presenting cell activities that affect both innate and adaptive immunity. Consequently, transgenic sheep over-expressing TLR4 are an suitable model to investigate the effects of TLR4 on preventing Brucellosis. In this study, we generated transgenic sheep overexpressing TLR4 and aimed to evaluate the effects of different seasons（breeding and non-breeding season） on superovulation and the imported exogenous gene on growth.Results： In total of 43 donor ewes and 166 recipient ewes in breeding season, 37 donor ewes and 144 recipient ewes in non-breeding season were selected for super-ovulation and injected embryo transfer to generate transgenic sheep.Our results indicated the no. of embryos recovered of donors and the rate of pronuclear embryos did not show any significant difference between breeding and non-breeding seasons（P 〉 0.05）. The positive rate of exogenous TLR4 tested were 21.21 % and 22.58 % in breeding and non-breeding season by Southern blot. The expression level of TLR4 in the transgenic sheep was 1.5 times higher than in the non-transgenic group（P 〈 0.05）. The lambs overexpressing TLR4 had similar growth performance with non-transgenic lambs, and the blood physiological parameters of transgenic and non-transgenic were both in the normal range and did not show any difference.Conclusions： Here we establish an efficient platform for the production of transgenic sheep by the microinjection of pronuclear embryos during the whole year. The over-expression of TLR4 had no adverse effect on the growth of the sheep.
PDF
