Explore the vast range of titles available.

The Gravity Recovery and Climate Experiment (GRACE) satellites and its successor mission, the GRACE Follow‐On (GRACE‐FO) satellites provide a unique capability to monitor terrestrial water storage anomalies (TWSA) and key hydrological variables associated with flood events. However, GRACE data is only available from 2002 onwards, which poses challenges for long‐term studies of terrestrial water storage and flooding. Additionally, the monthly temporal resolution of GRACE (‐FO) data limits its utility for detailed flood studies on finer time scales. Against these issues, this study employed a statistical model to reconstruct daily TWSA on a grid scale in China from 1963 to 2022. Considering that flood events have three‐dimensional spatiotemporal characteristics, this study identified 359 flood events that occurred in China between 1963 and 2022 using a three‐dimensional Image‐CONnectivity based FLOOD identification (ICON‐FLOOD) approach, combined with Normalized Daily Flood Potential Index (NDFPI) calculated from reconstructed daily TWSA and surface runoff. The spatiotemporal variations characteristics of flood events in China over the past 60 years were also analyzed. The results show that 60 flood events that were not recorded in these three disaster databases but actually occurred were detected. The average duration, intensity, and affected area have experienced an “increase‐decrease‐increase‐decrease‐increase” process. Notably, in the past 20 years, the duration, intensity, and affected area of flood events are increasing. The methods and findings of this study may provide valuable references for flood risk management and mechanism analysis.

Understanding mass (re‐)distribution within the Earth system, and addressing global challenges such as the impact of climate change on water resources requires global time‐variable terrestrial water storage (TWS) estimates along with reasonable uncertainty fields. The Gravity Recovery and Climate Experiment (GRACE) and GRACE‐FO satellite missions provide time‐variable gravity fields with full variance‐covariance information. A rigorous uncertainty propagation of these errors to TWS uncertainties is mathematically challenging and computationally inefficient. We propose a Monte Carlo Full Variance‐Covariance (MCFVC) error propagation approach to precisely compute TWS uncertainties. We also establish theoretical criteria to predict the actual convergence and accuracy of MCFVC, showing a convergence after 10,000 realizations with the relative error of 2.8% for variance and 4.7% for covariance at the confidence level of 95%. This can be achieved in few seconds using a single CPU to compute the uncertainties of each 1° resolution globally gridded TWS field. A validation against the rigorous error propagation method indicates relative differences of less than 0.8%. A global uncertainty assessment shows that neglecting the covariance of gravity coefficients can considerably bias the TWS uncertainties, that is, up to 60%, in some basins like Eyre. Flexibility of MCFVC allows the quantification of filtering impacts on the uncertainty of TWS fields, for example, up to 35% in the Tocantins River Basin. An empirical model is provided to reproduce GRACE‐like TWS uncertainty fields for hydrological studies. Finally, experiments of GRACE(‐FO) data assimilation for hydrological applications and sea‐level budget estimation are presented that indicate the importance of accounting for the full covariance information in these studies. Plain Language Summary Terrestrial water storage (TWS) represents a vertical summation of all available water of the Earth’s land surface including groundwater, soil layers, surface water, and snow. Therefore, understanding TWS changes is essential for hydrological assessments. Satellite gravity missions such as the Gravity Recovery and Climate Experiment (GRACE) and its Follow‐On mission (GRACE‐FO) provide a unique opportunity to estimate TWS globally. However, to use GRACE(‐FO)‐like TWS estimates in geophysical and hydrological studies, one needs to quantify their uncertainties reliably at desired spatial resolution. In this study, an efficient statistical Monte Carlo method is presented, which provides high flexibility of processing choices, and satisfies the accuracy needed to compute the uncertainties of GRACE(‐FO)‐like TWS products. The simplicity and generality of this method also allows it to be easily integrated in the operational data post‐processing chains. We demonstrate the importance of the full covariance estimation of TWS products in hydrological data assimilation and sea‐level budget estimation studies. Key Points A Monte Carlo Full Variance‐Covariance method is proposed to propagate errors of GRACE(‐FO) level‐2 data, where the covariance is hardly reached by traditional methods Considering full variance‐covariance information and filtering methods have considerable impacts on the uncertainty of GRACE(‐FO)‐like terrestrial water storage (TWS) fields An empirical model is provided to account for spatial‐temporal variation of GRACE(‐FO)‐like TWS uncertainty fields, and for hydrological studies

With each twist of the knife, a chilling new journey begins ... From a woman intent on bizarre revenge, to a restaurant critic with a morbid fear of the number thirteen; and from a man arranging a life-changing assignation, to a couple heading for a disaster-filled vacation ... In multi-million-copy bestselling author Peter James' collection of short stories we first come to meet Brighton's finest detective, Roy Grace, and read the tale that went on to inspire James' hugely successful novel, Dead Simple. James exposes the Achilles heel of each of his characters, and makes us question how well we can trust ourselves, and one another. Each tale carries a twist that will haunt readers for days after they turn the final page ... Combining every twisted tale from the ebook bestsellers Short Shockers One and Short Shockers Two, with a never-seen-before collection of new material, A Twist of the Knife shows Peter James as the undisputed grand master of storytellers with this sometimes funny, often haunting, but always shocking collection.

Regional floods result from various flood generation mechanisms. Traditional analyses mainly link flooding to extreme rainfall, with limited input from soil moisture. Total water storage (TWS) is a holistic measure of basin wetness, including additional storage components from surface water, snow, and groundwater. Utilizing a new 5‐day Gravity Recovery and Climate Experiment and its Follow On (GRACE(‐FO)) data set, we investigated the linkage between short‐term TWS anomaly (TWSA) and regional flooding. The 5‐day TWSA solutions revealed flood signals missed by monthly TWSA solutions. Global basins exhibit distinct storage‐discharge co‐evolution patterns, offering new insights into flood mechanisms and propensity. Our bivariate event analyses show the annual maximum river discharges co‐occur more often with the TWSA maxima than with precipitation in many basins. Further analyses revealed TWSA's time‐lagged effect on river discharge, particularly in basins susceptible to floods triggered by saturation‐excess runoff. The 5‐day TWSA provides a new source of information for enhancing global flood preparedness. Plain Language Summary Every year, floods impact millions of people and result in significant economic losses. Despite this, we still face uncertainties in flood forecasting. In this study, we evaluated a new 5‐day total water storage anomaly (TWSA) data set derived from the Gravity Recovery and Climate Experiment (GRACE) satellites for flood early warning. TWSA measures changes in snow, surface water, soil moisture, and groundwater storage, providing a direct way to assess how wet an area is. The 5‐day TWSA data help us understand for the first time the connection between sub‐monthly TWSA and regional river flooding. Our findings show the 5‐day TWSA reveals new flood signals that were previously not captured using monthly TWSA data. This finding fills a crucial gap in global flood early warning systems, helping us better predict and prepare for floods. Key Points We investigated the role of total water storage anomalies (TWSA) in mediating regional flooding using a new 5‐day GRACE(‐FO) data set Regional floods tend to have higher number of joint occurrences with the 5‐day TWSA extremes than with precipitation extremes The causal strength of 5‐day TWSA on river discharge is relatively high, suggesting its potential value for flood early warning

Presents the adventures of the Grace children who have some unusual experiences after they discover a field guide to fairies and other creatures, in a text that includes the author's sketchbook.

Time-variable gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) missions have opened up a new avenue of opportunities for studying large-scale mass redistribution and transport in the Earth system. Over the past 19 years, GRACE/GRACE-FO time-variable gravity measurements have been widely used to study mass variations in different components of the Earth system, including the hydrosphere, ocean, cryosphere, and solid Earth, and significantly improved our understanding of long-term variability of the climate system. We carry out a comprehensive review of GRACE/GRACE-FO satellite gravimetry, time-variable gravity fields, data processing methods, and major applications in several different fields, including terrestrial water storage change, global ocean mass variation, ice sheets and glaciers mass balance, and deformation of the solid Earth. We discuss in detail several major challenges we need to face when using GRACE/GRACE-FO time-variable gravity measurements to study mass changes, and how we should address them. We also discuss the potential of satellite gravimetry in detecting gravitational changes that are believed to originate from the deep Earth. The extended record of GRACE/GRACE-FO gravity series, with expected continuous improvements in the coming years, will lead to a broader range of applications and improve our understanding of both climate change and the Earth system.

The last words Nick Walton hears from his fiancee, Logan Somervile, are in a terrified mobile phone call from her. She has just driven into the underground car park beneath the block of flats where they live in Brighton. Then she screams and the phone goes dead. The police are on the scene within minutes, but Logan has vanished, leaving behind her neatly parked car and telephone. That same afternoon, workmen digging up an old asphalt pat in a park in another part of the city, unearth the remains of a young woman in her early twenties, who has been dead for 30 years. At first, to Roy Grace and his team, these two events seem totally unconnected. But then another young woman in Brighton goes missing and another body from the past surfaces. Meanwhile, an eminent London psychiatrist meets with a man who claims to know a piece of information about Logan. Later Roy Grace makes the chilling realization that this one thing is the key to both the past and the present ... Brighton has its first serial killer in over eighty years.

We investigate the climatology of Neutral Density Disturbances (NDDs) collocated with Equatorial Plasma Irregularities (EPIs) at altitudes above 450 km by using 20 years of data from the Gravity Recovery and Climate Experiment (GRACE) and GRACE‐FO satellites. Electron density data are used to detect EPIs, and thermospheric neutral density measured onboard the same spacecraft serves to identify EPI‐related NDDs. A detailed analysis focused on the morphological similarity between electron and neutral densities. To examine the relationship between EPI and NDD, statistical dependences of EPIs and NDDs on season/longitude (S/L), Magnetic Latitude (MLAT), Magnetic Local Time (MLT), and solar activity have been checked. As a first step, we confirmed that the EPI climatology in GRACE satellite data is consistent with previous reports. Then, it is found that the lower the neutral density in the background upper thermosphere, the higher the probability that EPI can accompany NDDs. We suggest that the vertical plasma advection surrounding EPI can result in neutral density disturbance, of which the efficiency depends on the background neutral scale height or temperature. The colder the thermosphere, the shorter its vertical scale height (or the lower the background neutral density), which can make the plasma advection leave measurable imprints on the neutral density.