Surface soil moisture (SSM) is a key limiting factor for vegetation growth in alpine meadow on the Qinghai-Tibetan Plateau (QTP). Patches with various sizes and types may cause the redistribution of SSM by changing soil hydrological processes, and then trigger or accelerate alpine grassland degradation. Therefore, it is vital to understand the effects of patchiness on SSM at multi-scales to provide a reference for alpine grassland restoration. However, there is a lack of direct observational evidence concerning the role of the size and type of patches on SSM, and little is known about the effects of patches pattern on SSM at plot scale. Here, we first measured SSM of typical patches with different sizes and types at patch scale and investigated their patterns and SSM spatial distribution through unmanned aerial vehicle (UAV)-mounted multi-type cameras at plot scale. We then analyzed the role of the size and type of patchiness on SSM at both patch and plot scales. Results showed that: (1) in situ measured SSM of typical patches was significantly different (P < 0.01), original vegetation patch (OV) had the highest SSM, followed by isolate vegetation patch (IV), small bare patch (SP), medium bare patch (MP) and large bare patch (LP); (2) the proposed method based on UAV images was able to estimate SSM (0-40 cm) with a satisfactory accuracy (R-2 = 0.89, P < 0.001); (3) all landscape indices of OV, with the exception of patch density, were positively correlated with SSM at plot scale, while most of the landscape indices of LP and IV showed negative correlations (P < 0.05). Our results indicated that patchiness intensified the spatial heterogeneity of SSM and potentially accelerated the alpine meadow degradation. Preventing the development of OV into IV and the expansion of LP is a critical task for alpine meadow management and restoration.

The pedunculate oak (Quercus robur L.) is a major tree species in Europe, but it has faced recent growth decline and dieback events in some areas resulting in economic and ecosystem losses. In the southeastern edge of its natural distribution in eastern Romania, rising temperatures since the 1980s, when a shift towards warmer and more arid conditions occurred, increased evaporative demand and triggered growth decline. We analyzed the adaptive potential of six oak stands (333 individual trees) with ages ranging between 97 and 233 years, located in three wet and three dry sites. Results showed unstable climate-growth correlations with a breakpoint after 1985 when climate warming intensified. Wet soil conditions from early spring to summer enhanced growth; on the contrary, a high evaporative demand linked to warmer conditions and greater potential evapotranspiration reduced growth, particularly in wet sites. After 1985, drought stress induced a reduction in latewood width in dry sites. The relationship between growth and summer-autumn drought intensified during the last decades in all sites. Warmer spring conditions negatively affected oak growth, particularly latewood production. Wet sites had lower resilience indices, and we also noted a post-1985 progressive reduction of growth resilience. Slow-growing trees from dry sites showed growth decline, which could be an early-warning signal of impending dieback and tree death. In contrast, fast-growing trees from wet sites showed sustained relative growth improvement, which was attributed to tree age and size effects. After 1985, the pedunculate oak is more vulnerable to drought damage in dry sites near the southeastern distribution limit in response to hotter winter-spring droughts.

海冰表面积雪深度是利用卫星测高技术反演海冰厚度的关键参数。基于ICESat-2和CryoSat-2测高卫星的协同观测数据（简称IS2CS），对比与评估卫星测高雪深估算的两种时空匹配方法（轨迹搜索法和格网搜索法），并对2018-2024年北极海冰生长期（10月至次年4月）积雪深度的时空分布特征进行分析。结果表明：（1）IS2CS轨迹法雪深与OIB实测数据具有较高的沿轨相关性，能够较好地捕获沿轨积雪深度的变化特征；（2）格网法雪深更适合表征大尺度积雪深度的空间分布和季节性变化特征，本文格网法雪深和GSFC雪深精度相当，在SIMBA数据的评估中本文格网法雪深性能优于GSFC雪深；（3）相比IS2CS雪深，MW99/AMSR2雪深相对偏厚，且在海冰生长期内季节性变化表征能力较弱；（4）海冰积雪深度呈现明显的时空差异，多年冰表面雪深普遍厚于一年冰表面雪深，春季雪深厚于秋冬季雪深。2018-2024年间，北极海冰表面积雪深度总体呈现减薄趋势，且多年冰区域的雪深减薄速率高于一年冰区域。研究成果为改进卫星测高雪深产品和优化海冰厚度反演算法提供了科学依据。

海冰表面积雪深度是利用卫星测高技术反演海冰厚度的关键参数。基于ICESat-2和CryoSat-2测高卫星的协同观测数据（简称IS2CS），对比与评估卫星测高雪深估算的两种时空匹配方法（轨迹搜索法和格网搜索法），并对2018-2024年北极海冰生长期（10月至次年4月）积雪深度的时空分布特征进行分析。结果表明：（1）IS2CS轨迹法雪深与OIB实测数据具有较高的沿轨相关性，能够较好地捕获沿轨积雪深度的变化特征；（2）格网法雪深更适合表征大尺度积雪深度的空间分布和季节性变化特征，本文格网法雪深和GSFC雪深精度相当，在SIMBA数据的评估中本文格网法雪深性能优于GSFC雪深；（3）相比IS2CS雪深，MW99/AMSR2雪深相对偏厚，且在海冰生长期内季节性变化表征能力较弱；（4）海冰积雪深度呈现明显的时空差异，多年冰表面雪深普遍厚于一年冰表面雪深，春季雪深厚于秋冬季雪深。2018-2024年间，北极海冰表面积雪深度总体呈现减薄趋势，且多年冰区域的雪深减薄速率高于一年冰区域。研究成果为改进卫星测高雪深产品和优化海冰厚度反演算法提供了科学依据。

海冰表面积雪深度是利用卫星测高技术反演海冰厚度的关键参数。基于ICESat-2和CryoSat-2测高卫星的协同观测数据（简称IS2CS），对比与评估卫星测高雪深估算的两种时空匹配方法（轨迹搜索法和格网搜索法），并对2018-2024年北极海冰生长期（10月至次年4月）积雪深度的时空分布特征进行分析。结果表明：（1）IS2CS轨迹法雪深与OIB实测数据具有较高的沿轨相关性，能够较好地捕获沿轨积雪深度的变化特征；（2）格网法雪深更适合表征大尺度积雪深度的空间分布和季节性变化特征，本文格网法雪深和GSFC雪深精度相当，在SIMBA数据的评估中本文格网法雪深性能优于GSFC雪深；（3）相比IS2CS雪深，MW99/AMSR2雪深相对偏厚，且在海冰生长期内季节性变化表征能力较弱；（4）海冰积雪深度呈现明显的时空差异，多年冰表面雪深普遍厚于一年冰表面雪深，春季雪深厚于秋冬季雪深。2018-2024年间，北极海冰表面积雪深度总体呈现减薄趋势，且多年冰区域的雪深减薄速率高于一年冰区域。研究成果为改进卫星测高雪深产品和优化海冰厚度反演算法提供了科学依据。

The wheat powdery mildew (WPM) is one of the most severe crop diseases worldwide, affecting wheat growth and causing yield losses. The WPM was a bottom-up disease that caused the loss of cell integrity, leaf wilting, and canopy structure damage with these symptoms altering the crop's functional traits (CFT) and canopy spectra. The unmanned aerial vehicle (UAV)-based hyperspectral analysis became a mainstream method for WPM detection. However, the CFT changes experienced by infected wheats, the relationship between CFT and canopy spectra, and their role in WPM detection remained unclear, which might blur the understanding for the WPM infection. Therefore, this study aimed to propose a new method that considered the role of CFT for detecting WPM and estimating disease severity. The UAV hyperspectral data used in this study were collected from the Plant Protection Institute's research demonstration base, Xinxiang city, China, covering a broad range of WPM severity (0-85 %) from 2022 to 2024. The potential of eight CFT [leaf structure parameter (N), leaf area index (LAI), chlorophyll a + b content (Cab), carotenoids (Car), Car/Cab, anthocyanins (Ant), canopy chlorophyll content (CCC) and average leaf angle (Deg)] obtained from a hybrid method combining a radiative transfer model and random forest (RF) and fifty-five narrow-band hyperspectral indices (NHI) was explored in WPM detection. Results indicated that N, Cab, Ant, Car, LAI, and CCC showed a decreasing trend with increasing disease severity, while Deg and Car/Cab exhibited the opposite pattern. There were marked differences between healthy samples and the two higher infection levels (moderate and severe infection) for Cab, Car, LAI, Deg, CCC, and Car/Cab. N and Ant only showed significant differences between the healthy samples and the highest infection level (severe infection). As Cab, Car, and Ant decreased, the spectral reflectance in the visible light region increased. The decrease in N and LAI was accompanied by a reduction in reflectance across the entire spectral range and the near-infrared area, which was exactly the opposite of Deg. The introduction of CFT greatly improved the accuracy of the WPM severity estimation model with R2 of 0.92. Features related to photosynthesis, pigment content, and canopy structure played a decisive role in estimating WPM severity. Also, results found that the feature importance showed a remarkable interchange as increasing disease levels. Using features that described canopy structure changes, such as optimized soil adjusted vegetation index, LAI, visible atmospherically resistant indices, and CCC, the mild infection stage of this disease was most easily distinguished from healthy samples. In contrast, most severe impacts of WPM were best characterized by features related to photosynthesis (e.g., photochemical reflectance index 515) and pigment content (e.g., normalized phaeophytinization index). This study help deepen the understanding of symptoms and spectral responses caused by WPM infection.

Rapid urbanization and industrial growth in China have increased brownfield site reclamation, the sustainable remediation for urban transformation and enhancing ecosystem services. However, traditional brownfield safety assessment strategies impose unnecessary costs since excessive remediation. Herein, a comprehensive system integrated by soil self-purification, potential ecological risks and human health risks is developed to investigate the safety of brownfield sites. Indices, including soil environmental loading capacity (SELC), and Nemerow integrated pollution index (NIPI), were introduced to assess heavy metals (HMs) pollution. Results show that 72.05% of the sites are identified as moderate pollution, where Cd, As, and Cr(VI) are at heavy pollution, incorporating soil self-purification. The average values of potential ecological risk (PERI) reached 6615.00, posing a significant damage to the local ecosystem, and Cd was identified as main ecological hazards in the study sites. Furthermore, the health risk assessment shows that children's health risks are higher than that of adults, with non-carcinogenic risk to children (2.60) and adults (0.41), and carcinogenic risk to children (2.30 x 10-3) and adults (1.12 x 10-4). Utilizing a multi-index decision-making approach, it is determined that 19.30% of the site exhibit high-risk values, between concentration screening (11.40%) and risk screening (83.30%) base on single-indices. The study sheds light on the comprehensive assessment of brownfield site safety.

Waves can cause significant accumulation of pore water pressure and liquefaction in seabed soils, leading to instability of foundations of marine hydrokinetic devices (MHKs). Geostatic shear stresses (existing around foundations, within slopes, etc.) can substantially alter the rate of pore pressure buildup, further complicating the liquefaction susceptibility assessments. In this study, the development of wave-induced residual pore water pressure and liquefaction within sandy seabed slopes supporting MHK structures is evaluated. Unlike most earlier studies that excluded the impact of shear stress ratios (SSR) on the residual pore pressure response of sloping seabeds, asymmetrical cyclic loadings are considered herein for a range of SSRs. To obtain wave-induced loading in the seabed (and cyclic shear stress ratios, CSRs), the poroelasticity equations governing the seabed response, coupled with those for fluid and structure domains, are solved simultaneously. Utilizing an experimental model based on anisotropic cyclic triaxial test data that includes CSR and SSR impacts, an equation for the rate of pore pressure buildup is developed and added as a source term to the 2D consolidation equation. Numerical investigations were performed by developing finite element models in time domain. The models were calibrated using particle swarm optimization method and validated against wave flume experimental data. The results indicate that the consideration of static shear stresses has led to sudden rise in residual pore pressures followed by fast dissipations at early and late time steps, respectively, beneath the structure. The exclusion of SSR is shown to cause significant overestimation of pore pressure accumulations at late cycles, potentially causing significant overdesign of MHK foundations. The impact of proximity to the free drainage boundary, CSR amplitude, and loading frequency on the accumulation of residual pore pressure is illustrated. The residual liquefaction susceptibility of the seabed is shown to decline by increase of the seabed slope angle.

重复轨道法是利用测高卫星监测南极冰盖高程变化的重要方法。在利用重复轨道方法计算冰盖高程变化时，引入一种基于抗差估计的方法（insrtitue of geodesy and geophysicsⅢ，IGGⅢ）取代传统的最小二乘方法（least square,LS）。利用2019年3月至2021年12月的ICESat-2陆冰高程数据，分别采用LS方法和IGGⅢ方法在东南极Totten冰川流域进行了实验。结果表明，该流域分别呈现出-0.038±0.163 m/yr和-0.040±0.136 m/yr的高程降低趋势，说明IGGⅢ抗差估计方法能够在保留重复轨道方法高数据利用率的基础上，有效地减少异常数据被错误引入产生的误差。利用MEaSUREs ITS＿LIVE高程变化产品对两种方法计算的结果进行了对比，IGGⅢ方法的结果在空间分布上具有更好的一致性。

重复轨道法是利用测高卫星监测南极冰盖高程变化的重要方法。在利用重复轨道方法计算冰盖高程变化时，引入一种基于抗差估计的方法（insrtitue of geodesy and geophysicsⅢ，IGGⅢ）取代传统的最小二乘方法（least square,LS）。利用2019年3月至2021年12月的ICESat-2陆冰高程数据，分别采用LS方法和IGGⅢ方法在东南极Totten冰川流域进行了实验。结果表明，该流域分别呈现出-0.038±0.163 m/yr和-0.040±0.136 m/yr的高程降低趋势，说明IGGⅢ抗差估计方法能够在保留重复轨道方法高数据利用率的基础上，有效地减少异常数据被错误引入产生的误差。利用MEaSUREs ITS＿LIVE高程变化产品对两种方法计算的结果进行了对比，IGGⅢ方法的结果在空间分布上具有更好的一致性。