The southeastern mountainous (SEM) region of China has experienced significant fluctuations in groundwater levels since the early 21st century. Monitoring groundwater storage (GWS) dynamics and analyzing its spatiotemporal distribution are crucial for the sustainable management of water resources. This study constructs a groundwater storage anomaly (GWSA) dataset for the SEM region of China from 2003 to 2019 using GRACE satellite data released by CSR, combined with multiple auxiliary datasets. Methods such as the Mann-Kendall test, improved ridge regression, and wavelet analysis were employed to assess the spatiotemporal variation of GWS across the entire basin. The results indicate that the overall GWSA in the basin exhibited a slow increase until 2016, followed by a rapid decline, likely driven by human activities. The estimated increase rate was approximately 0.383 cm/yr, whereas the decline rate reached −1.117 cm/yr. In the southern hilly areas, variations in soil moisture storage were primarily influenced by precipitation, while in more complex terrains, groundwater consumption played a more dominant role in shaping GWSA trends. In highly urbanized regions, water use for domestic, environmental, and infrastructure purposes was the primary driver of GWS changes. Furthermore, the correlation between GWSA and the Oceanic Niño Index (ONI) suggests that climate change exerts a significant influence on groundwater dynamics in coastal areas over long periods (>2 years), while its impact is relatively weaker in inland regions.

Frequency modulated continuous wave (FMCW) radar is an advantageous sensor scheme for target estimation and environmental perception. However, existing algorithms based on discrete Fourier transform (DFT), multiple signal classification (MUSIC) and compressed sensing, etc., cannot achieve both low complexity and high resolution simultaneously. This paper proposes an efficient 2-D MUSIC algorithm for super-resolution target estimation/tracking based on FMCW radar. Firstly, we enhance the efficiency of 2-D MUSIC azimuth-range spectrum estimation by incorporating 2-D DFT and multi-level resolution searching strategy. Secondly, we apply the gradient descent method to tightly integrate the spatial continuity of object motion into spectrum estimation when processing multi-epoch radar data, which improves the efficiency of continuous target tracking. These two approaches have improved the algorithm efficiency by nearly 2–4 orders of magnitude without losing accuracy and resolution. Simulation experiments are conducted to validate the effectiveness of the algorithm in both single-epoch estimation and multi-epoch tracking scenarios.

The M_S8.0 Wenchuan earthquake occurred on May 12th, 2008 on the steeply reverse fault of the Longmen Shan fault zone, Western China. Catastrophic failure and rupture occurred along the listric sliding surface. Several numerical simulations have been performed to reconfigure the dynamic processes of this strong earthquake. However, few scientific studies on the stick-slip of the listric fault have been conducted. In this study, finite element method is utilized to simulate the instant stick-slip fault responses at the triggering moment. The fault surface is a non-continuous and frictional contact interface. The simulation results demonstrated that the sliding friction and sticking friction interact spatially. This interaction occurred temporarily on swarms of slip patches, rather than the entire fault slipping surface. Stick-slip causes serrated energy release, and transient aseismic slip can occur spontaneously. These tremors propagate from the epicenter upwards to the ground surface. Therefore, they may provide important details on earthquake onset rupture.