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The economic consequences of drought episodes are increasingly important, although they are often difficult to apprehend in part because of the complexity of the underlying mechanisms. In this article, we will study one of the consequences of drought, namely the risk of subsidence (or more specifically clay shrinkage induced subsidence), for which insurance has been mandatory in France for several decades. Using data obtained from several insurers, representing about a quarter of the household insurance market, over the past twenty years, we propose some statistical models to predict the frequency but also the intensity of these droughts, for insurers, showing that climate change will have probably major economic consequences on this risk. But even if we use more advanced models than standard regression-type models (here random forests to capture non linearity and cross effects), it is still difficult to predict the economic cost of subsidence claims, even if all geophysical and climatic information is available.

This paper proposes deep convolutional neural networks to detect and map localized, rapid subsidence caused by mining activities using time-series Sentinel-1 SAR images. A deformation detection network (DDNet) is developed to automatically identify rapidly subsiding areas from wrapped interferograms, and a phase unwrapping network (PUNet) is designed to unwrap the cropped interferogram patches centered on the detected subsiding locations. To train the two networks, interferogram simulation strategies are developed to generate various training samples using the distorted two-dimensional Gaussian surface and fractal Perlin noises. The performance of the DDNet is verified by simulations on a synthetic dataset with 13 large interferograms, while the PUNet is evaluated by simulations using synthetic datasets with different levels of deformation gradients and noises. Compared with the traditional and deep-learning methods, the PUNet exhibits excellent performance and efficiency in unwrapping interferograms with rapid mining-induced deformation. The proposed networks are further verified by applying them to Shanxi Province, China, which is characterized by serious ground subsidence hazards caused by long-term coal mining activities. The time-series deformations of 1,344 detected subsidence areas are calculated with the vertical velocities ranging from -19.7 cm/year to -254.8 cm/year. The results are validated using the ascending and descending Sentinel-1 Interferograms and an L-band ALOS-2 interferogram covering the same area within the acquisition period, showing highly consistent vertical deformation rates. The proposed strategy and methods introduce deep learning to the time-series InSAR processing chain and may have profound implications on the detection and monitoring of localized mining-induced deformation using InSAR.

This study investigates the role of convection–circulation coupling on the simulated eastward propagation of the Madden–Julian Oscillation (MJO) over the Maritime Continent (MC). Experiments are conducted with the European Centre Hamburg Model Version 5 (ECHAM5) coupled with the one-column ocean model—Snow-Ice-Thermocline (SIT) and two different cumulus schemes, Nordeng-Tiedtke (E5SIT-Nord) and Tiedtke (E5SIT-Tied). During the early phase of MJO composites, the E5SIT-Nord simulation reveals stronger intraseasonal anomalies in the apparent heat source (Q1) over the convective center, however, the E5SIT-Tied produces a stronger background Q1, suggesting that deep convection prevails over the MC but does not couple with the MJO circulation. Similarly, in the E5SIT-Tied simulation, in-column moisture is kept mostly by local deep convection over the MC, which is in contrast to the well-correlated relationship between moisture anomaly and MJO circulation in E5SIT-Nord. A case study based on an observational MJO reveals similar biases concerning of convection–circulation coupling emerges within a few days of simulations. The E5SIT-Tied simulation produces weaker heating at the convective center of the MJO than the E5SIT-Nord a few days after model initiation, resulting weaker subsidence to the east and less favorable for propagation. The present findings highlight the instantaneous responses of cumulus parameterization schemes to MJO-related environmental changes can further affect intraseasonal variability through altering convection–circulation coupling over the MC. Physical schemes of moist convection are essential to realistically represent this coupling and thereby improve the simulation of the eastward propagation of the MJO.

Sea surface temperature (SST) reconstructions based on isoprenoid glycerol dialkyl glycerol tetraether (isoGDGT) distributions from the Eocene southwest (SW) Pacific Ocean are unequivocally warmer than can be reconciled with state-of-the-art fully coupled climate models. However, the SST signal preserved in sedimentary archives can be affected by contributions of additional isoGDGT sources. Methods now exist to identify and possibly correct for overprinting effects on the isoGDGT distribution in marine sediments. Here, we use the current proxy insights to (re-)assess the reliability of the isoGDGT-based SST signal in 69 newly analyzed and 242 reanalyzed sediments at Ocean Drilling Program (ODP) Site 1172 (East Tasman Plateau, Australia) following state-of-the-art chromatographic techniques. We compare our results with paleoenvironmental and paleoclimatologic reconstructions based on dinoflagellate cysts. The resulting ∼ 130 kyr resolution Maastrichtian–Oligocene SST record based on the TetraEther indeX of tetraethers with 86 carbon atoms (TEX86) confirms previous conclusions of anomalous warmth in the early Eocene SW Pacific and remarkably cool conditions during the mid-Paleocene. Dinocyst diversity and assemblages show a strong response to the local SST evolution, supporting the robustness of the TEX86 record. Soil-derived branched GDGTs stored in the same sediments are used to reconstruct mean annual air temperature (MAAT) of the nearby land using the Methylation index of Branched Tetraethers with 5-methyl bonds (MBT'5me) proxy. MAAT is consistently lower than SST during the early Eocene, independent of the calibration chosen. General trends in SST and MAAT are similar, except for (1) an enigmatic absence of MAAT rise during the Paleocene–Eocene Thermal Maximum and Middle Eocene Climatic Optimum, and (2) a subdued middle–late Eocene MAAT cooling relative to SST. Both dinocysts and GDGT signals suggest a mid-shelf depositional environment with strong river runoff during the Paleocene–early Eocene progressively becoming more marine thereafter. This trend reflects gradual subsidence and more pronounced wet/dry seasons in the northward-drifting Australian hinterland, which may also explain the subdued middle Eocene MAAT cooling relative to that of SST. The overall correlation between dinocyst assemblages, marine biodiversity and SST changes suggests that temperature exerted a strong influence on the surface-water ecosystem. Finally, we find support for a potential temperature control on compositional changes of branched glycerol monoalkyl glycerol tetraethers (brGMGTs) in marine sediments. It is encouraging that a critical evaluation of the GDGT signals confirms that most of the generated data are reliable. However, this also implies that the high TEX86-based SSTs for the Eocene SW Pacific and the systematic offset between absolute TEX86-based SST and MBT'5me-based MAAT estimates remain without definitive explanation.

Objective: We aimed to examine the long-term radiological and clinical outcomes after stand-alone anterior cervical discectomy and fusion (ACDF).Methods: In total, we enrolled 20 patients and 31 treated segments with degenerative cervical disease that underwent stand-alone ACDF with ≥60 months of follow-up. Segmental angle (SA), cervical sagittal alignment (CSA), subsidence, and fusion were evaluated. A visual analogue scale (VAS) and the neck disability index (NDI) were applied pre- and post-operatively and at the last follow-up.Results: Subsidence occurred in 9 (45%) patients and 15 segments (48.4%) at the last follow-up. The mean VAS and NDI scores had improved in both groups with and without subsidence. The mean SA at the last follow-up had significantly increased to 2.3°±8.5° in the subsidence group and to 1.7°± 5.2° degree in the non-subsidence group compared to the post-operative SA (p

It is imperative for the mining area to timely and accurately predict the longwall progressive subsidence basin. However, the mainstream method that uses time function still has limitations, which impede extensive application. In this study, we analyzed the flaws of the optimized segmented Knothe time function in detail, and expounded the possible improvement directions. Subsequently, we proposed the Gompertz time function for predicting longwall progressive subsidence basin, based on the modeling idea that three origins are consistent. Afterward, we analyzed the variation law between parameters of the Gompertz time function and the geological mining conditions, and elaborated the parameter calculation method and the prediction algorithm for the longwall progressive subsidence basin. Finally, we demonstrated the practical application effect of this method with experiments. The average RMSE and average relative RMSE of predicted progressive subsidence using the Gompertz time function are 58.4 mm and 6.9%, respectively, and compared with the same statistics using the optimized segmented Knothe time function, the accuracy is increased by 27.9% on average. The results show that the accuracy of this article proposed method can achieve centimeter-level, meet the requirements of practical engineering application, and this method is expected to enable the mining proceeding in a safe, effective and environmentally sustainable way.

This study investigated the environmental geochemical characteristics of rare-earth elements (REEs) in surface waters in the Huainan mining area, Anhui Province, China. The REEs concentrations were determined by ICP-MS, and the inorganic species of dissolved REEs in the river and coal mining subsidence area water samples were calculated by using the Visual MINTEQ (version 3.1) code. On this basis, the distribution and geochemical characteristics of REEs in the surface waters were systematically analyzed, and the main inorganic species of REEs were investigated. The results showed the following: (1) The REEs concentrations in the surface waters were relatively low, ranging from 0.1361 to 0.3536 μg/L, and the average ∑REEs concentration was 0.2062 μg/L. Compared with light rare-earth elements (LREEs), heavy rare-earth elements (HREEs) were significantly enriched, with an average enrichment factor of 1.4642. Due to the interaction of high pH values and high cation concentrations, the ∑REEs content in the subsidence area water was significantly lower than that in the river water. (2) The distribution pattern of REEs in the surface waters normalized against the North American Shale Composite (NASC) showed that the REEs in the study area had different degrees of cerium (Ce) and europium (Eu) anomalies. The negative Ce anomalies were probably closely related to the pH conditions, whereas the positive Eu anomalies were mainly attributed to preferential chemical weathering and the dissolution of feldspar minerals. (3) The simulation results obtained by using Visual MINTEQ code showed that the dominant and typically inorganic complex form of REEs in the surface waters was carbonate complexes, and this form was one of the reasons for the enrichment of HREEs in the surface water.

Presently, ground subsidence in urban areas is becoming a peril to the infrastructure and society. In this study, we conducted a detailed analysis of the results, based on the Persistent Scatterer ...

Background For lumbar degenerative diseases, cage subsidence is a serious complication and can result in the failure of indirect decompression in the oblique lumbar interbody fusion (OLIF) procedure. Whether additional lateral plate fixation was effective to improve clinical outcomes and prevent cage subsidence was still unknown. This study aimed to compare the incidence and degree of cage subsidence between stand-alone oblique lumbar interbody fusion (SA-OLIF) and OLIF combined with lateral plate fixation (OLIF + LP) for the treatment of lumbar degenerative diseases and to evaluate the effect of the lateral plate fixation. Methods This was a retrospective comparative study. 20 patients with 21 levels underwent SA-OLIF and 21 patients with 26 levels underwent OLIF + LP. We compared clinical and radiographic outcomes between two groups. Clinical evaluation included Visual Analog Scale (VAS) for back pain and leg pain, Japanese Orthopaedic Association (JOA) scores and Oswestry Disability Index (ODI). Radiographical evaluation included disc height (DH), segmental lordosis angle (SL), and subsidence rate on standing lateral radiographs. Cage subsidence was classified using Marchi’s criteria. Results The mean follow-up duration was 6.3 ± 2.4 months. There were no significant differences among perioperative data (operation time, estimated intraoperative blood loss, and complication), clinical outcome (VAS, ODI, and JOA) and radiological outcome (SH and SL). The subsidence rate was 19.0% (4/21) in SA-OLIF group and 19.2% (5/26) in OLIF + LP group. 81.0% in SA-OLIF group and 80.8% in OLIF + LP group had Grade 0 subsidence, 14.3% in SA-OLIF group and 15.4% in OLIF + LP group had Grade I subsidence, and 4.8% in SA-OLIF group and 3.8% in OLIF + LP group had Grade II subsidence (P = 0.984). One patient with severe cage subsidence and lateral plate migration underwent revision surgery. Conclusions The additional lateral plate fixation does not appear to be more effective to prevent cage subsidence in the oblique lumbar interbody fusion, compared with stand-alone technique. If severe cage subsidence occurs, it may result in lateral plate migration in OLIF combined with lateral plate fixation.

Extensive regions of marine boundary layer cloud impact the radiative balance through their significant shortwave albedo while having little impact on outgoing longwave radiation. Despite this importance, these cloud systems remain poorly represented in large-scale models due to difficulty in representing the processes that drive their life cycle and coverage. In particular, the mesoscale organization and cellular structure of marine boundary clouds have important implications for the subsequent cloud feedbacks. In this study, we use long-term (2013–2018) observations from the Atmospheric Radiation Measurement (ARM) Facility's Eastern North Atlantic (ENA) site on Graciosa Island, Azores, Portugal, to identify cloud cases with open- or closed-cellular organization. More than 500 h of each organization type are identified. The ARM observations are combined with reanalysis and satellite products to quantify the cloud, precipitation, aerosol, thermodynamic, and large-scale synoptic characteristics associated with these cloud types. Our analysis shows that both cloud organization populations occur during similar sea surface temperature conditions, but the open-cell cases are distinguished by stronger cold-air advection and large-scale subsidence compared to the closed-cell cases, consistent with their formation during cold-air outbreaks. We also find that the open-cell cases were associated with deeper boundary layers, stronger low-level winds, and higher rain rates compared to their closed-cell counterparts. Finally, raindrops with diameters larger than 1 mm were routinely recorded at the surface during both populations, with a higher number of large drops during the open-cellular cases. The similarities and differences noted herein provide important insights into the environmental and cloud characteristics during varying marine boundary layer cloud mesoscale organization and will be useful for the evaluation of model simulations for ENA marine clouds.

The formation of tropical cyclones (TCs) in unfavorable large-scale environments remains a challenge for TC forecasting. Tropical Storm (TS) Cindy (2017) formed at 1800 UTC 20 June 2017 in the Gulf of Mexico despite strong vertical wind shear, low midtropospheric relative humidity, and poorly organized convection. A key to TC genesis is the initial development of a warm core within an emergent cyclonic vortex, a process that occurs on small spatial scales and is often difficult to observe. TS Cindy was observed during the Convective Processes Experiment (CPEX) field campaign in 2017 by the NASA DC-8 aircraft, equipped with a Doppler wind lidar, precipitation radar, and GPS dropsondes. This study combines CPEX observations and a cloud-resolving, fully coupled atmosphere–wave–ocean numerical simulation to investigate the formation of TS Cindy. Prior to TC genesis, a shallow cyclonic circulation was embedded in a deep layer of west-southwesterly flow associated with an upper-level trough. Within the disturbance, a warm and dry anomaly was observed by dropsondes near the center of the cyclonic circulation, with a maximum at about the 2.5-km level. In the coupled model simulation, the temperature perturbation reached 5°C along with a dewpoint temperature depression of 8°C. Backward trajectory analysis shows that subsidence is primarily associated with a thermally indirect circulation along the western flank of the storm. Air parcels descend more than 1000 m toward the lower troposphere while warming up by 9°–12°C. The subsidence-induced virtual temperature perturbation in the 1.5–3.5-km layer accounts for 50% of the sea level pressure depression. Subsidence warming, therefore, played a key role in the genesis of TS Cindy.

Ensuring the reliability and durability of buildings and structures built on subsident soils is one of the important tasks. Subsidence of the soil can lead to a violation of the strength of buildings and structures and the impossibility of their further operation. It is necessary to improve the existing methods of preparing the foundation. This article discusses the experience of using the method of soaking the thickness of subsident soils in combination with the device of a rammed soil cushion. Works on compaction of subsident soils by soaking and tamping are carried out sequentially on three maps. Soaking is carried out through trenches with a depth of 2...3 m, a width of 2.0 m. All the soil from the trenches is stored inside the maps to create a load, as a result of which an additional pressure on the soil is created, equal to 10...30 kPa. At the next stage, local pits are rammed under the buildings according to a given grid, which are filled with local soil with layer-by-layer compaction. Compacted areas around the pits overlap, and as a result, a rammed soil cushion is created, which makes up a single compacted array. Thus, the elimination of subsidence properties of the soil is achieved.

To better understand the dynamics and impacts of blocking events, their 3D structure needs to be further investigated. We present a comprehensive composite analysis of the 3D structure of blocks and its response to future climate change over North Pacific, North Atlantic, and Russia in summers and winters using reanalysis and two large-ensemble datasets from CESM1 and GFDLCM3. In reanalysis, over both ocean and land, the anomalous winds are equivalent-barotropic in the troposphere and stratosphere, and temperature anomalies are positive throughout the troposphere and negative in the lower stratosphere. The main seasonal and regional differences are that blocks are larger/stronger in winters; over oceans, the temperature anomaly is shifted westward due to latent heating. Analyzing the temperature tendency equation shows that in all three sectors, adiabatic warming due to subsidence is the main driver of the positive temperature anomaly; however, depending on season and region, meridional thermal advection and latent heating might have leading-order contributions too. Both GCMs are found to reproduce the climatological 3D structure remarkably well, but sometimes disagree on future changes. Overall, the future summertime response is weakening of all fields (except for specific humidity), although the impact on near-surface temperature is not necessarily weakened; e.g., the blocking-driven near-surface warming over Russia intensifies. The wintertime response is strengthening of all fields, except for temperature in some cases. Responses of geopotential height and temperature are shifted westward in winters, most likely due to latent heating. Results highlight the importance of process-level analyses of blocks’ 3D structure for improved understanding of the resulting temperature extremes and their future changes.

Monitoring and predicting mining area subsidence caused by coal mining help effectively control geological disasters. Information regarding small surface deformations can be obtained using a differential interferometric synthetic aperture radar (D-InSAR), which exhibits high monitoring accuracy and can cover large areas; thus, D-InSAR are being applied for mining area settlement monitoring. However, mining areas are prone to large gradient deformations in short durations; obtaining information regarding such deformations is outside the scope of D-InSAR monitoring. To adapt to the characteristics of D-InSAR monitoring, this study selected a Boltzmann function model with a slow boundary convergence rate to address the problem of probabilistic integration methods exhibiting a high boundary convergence rate. The three-dimensional surface deformation of the mining area can be accurately obtained. According to the projection relationship between D-InSAR line of sight (LOS) directional deformation, subsidence, and horizontal movement, a D-InSAR monitoring equation for mining subsidence assisted by Boltzmann is derived. This equation is combined with the shuffled frog leaping algorithm (SFLA) to obtain the parameters to be estimated from the equation. The D-InSAR LOS deformation information of the 13121 working face in the Huainan mining area was obtained from July 14 to October 30, 2019. The proposed method was then used to obtain the predicted parameters of the working face under insufficient mining. The predicted parameters of mining subsidence were calculated to obtain the predicted parameters when it was fully mined. Then, the revised parameters were used to predict the subsidence and horizontal movement of the mining area and compared with the actual leveling observations. The results show that the mean square error of predicted subsidence is 97.1 mm, which is about 3.09% of the maximum subsidence value; the mean square error of predicted horizontal movement is 46.1 mm, which is about 4.1% of the maximum horizontal movement value. The predicted results of the aforementioned method were used to analyze the damage to the buildings above the working face and determine the damage level of the buildings to provide a reference for the demolition and maintenance of the Zhaimiao village.

Rapid intensification of near-landfall tropical cyclones is very difficult to predict, and yet has far-reaching consequences due to their disastrous impact to the coastal areas. The focus for improving predictions of rapid intensification has so far been on environmental conditions. Here we use the Coupled-Ocean-Atmosphere-Wave-Sediment Transport Modeling System to simulate tropical cyclones making landfall in South China: Nida (2016), Hato (2107) and Mangkhut (2018). Two smaller storms (Hato and Nida) undergo intensification, which is induced by the storms themselves through their extensive subsidence ahead of the storms, leading to clear skies and strong solar heating of the near-shore sea water over a shallow continental shelf. This heating provides latent heat to the storms, and subsequently intensification occurs. In contrast, such heating does not occur in the larger storm (Mangkhut) due to its widespread cloud cover. This results imply that to improve the prediction of tropical cyclone intensity changes prior to landfall, it is necessary to correctly simulate the short-term evolution of near-shore ocean conditions. Air subsidence ahead of tropical cyclones can bring on rapid intensification and consequent clear skies that warm the water column in shallow shelf waters and under limited cloud cover, according to experiments with a coupled ocean-atmosphere model.

This study analyzed the nature, mechanisms and drivers for hot-and-polluted episodes (HPEs) in the Pearl River Delta, China. Numerical model simulations were conducted for the summer and autumn of 2009–2011. A total of eight HPEs were identified, mainly occurring in August and September. K-means clustering was applied to group the HPEs into three clusters based on their characteristics and mechanisms. We found three HPEs were driven by weak subsidence and convection induced by approaching tropical cyclones (TC-HPE) and two HPEs were controlled by calm (stagnant) conditions (ST-HPE) with low wind speed in the lower atmosphere, whereas the remaining three HPEs were driven by the combination (hybrid) of both aforementioned systems (HY-HPE). A positive synergistic effect between the HPE and urban heat island (UHI; ∼ 1.1 ∘C increase) was observed in TC-HPE and ST-HPE, whereas no discernible synergistic effect was found in HY-HPE. Total aerosol radiative forcing (TARF) caused a reduction in temperature (0.5–1.0 ∘C) in TC-HPE and ST-HPE but an increase (0.5 ∘C) in HY-HPE.

Cartagena is subsiding at a higher rate compared to that of global climate-driven sea level rise. We investigate the relative sea level rise (RSLR) and the influence of vertical land movements in Cartagena through the integration of different datasets, including tide gauge records, GPS geodetic subsidence data, and Interferometric Synthetic Aperture Radar (InSAR) observations of vertical motions. Results reveal a long-term rate (> 60 years) of RSLR of 5.98 ± 0.01 mm/yr. The last two decades exhibited an even greater rate of RSLR of 7.02 ± 0.06 mm/yr. GPS subsidence rates range between − 5.71 ± 2.18 and − 2.85 ± 0.84 mm/yr. InSAR data for the 2014–2020 period show cumulative subsidence rates of up to 72.3 mm. We find that geologically induced vertical motions represent 41% of the observed changes in RSLR and that subsidence poses a major threat to Cartagena’s preservation. The geodetic subsidence rates found would imply a further additional RSLR of 83 mm by 2050 and 225 mm by 2100. The Colombian government should plan for the future and serve as an example to similar cities across the Caribbean.

Widespread catastrophic fog episodes in polluted northern India have been attributed to tropical cyclone activity in the Bay of Bengal & Arabian Sea; however, limited studies have been conducted on the effect of tropical cyclone intensity (‘T’ Numbers) on different fog characteristics in Indo Gangetic Basin, Northern India. In this study, different characteristics, including persistence, intensity, and areal extension, were analyzed at the Indira Gandhi International Airport, New Delhi during 1998–99, 2013–14, and 2016–17. A high-intensity tropical cyclone (Severe to Very Severe Cyclonic Storm) has been found to significantly increase the persistence, intensity, and areal extension of fog by inducing strong subsidence over the IGI Airport/Indo-Gangetic Basin. This knowledge is vital for improving the short-term forecasting of fog in the Indo-Gangetic Basin of Northern India and will further support the Government agencies to take preventive safety measures and planning well in advance time.

Objective Anterior cervical corpectomy using a titanium mesh cage may result in delayed nonunion and thus a change in cervical alignment, and patients may require revision surgery. We investigated the radiologic and clinical outcomes of cervical corpectomy and the risk factors for subsidence. Methods We studied 74 patients who underwent single-level anterior cervical corpectomy for cervical spondylotic myelopathy with or without ossification of the posterior longitudinal ligament between 2007 and 2014. Graft subsidence was considered present when there was a reduction in the anterior and posterior heights by an average of 4 mm or more 2 years after the operation. We measured cervical parameters before surgery, immediately after surgery, and 6, 12, and 24 months after surgery. The clinical outcomes were the neck and arm visual analog scale scores and reoperation rate. Results In the subsidence group, these values gradually decreased over the 24 months. The radiologic parameters did not differ between the 2 groups for 24 months after the onset of subsidence. There were no differences in clinical outcome or reoperation rate. In the analysis of the risk factors, subsidence occurred with a large T1 slope and a large change in the C27 Cobb angle (p=0.020 and p=0.026, respectively). Conclusion Subsidence gradually occurred after single-level anterior cervical corpectomy for up to 24 months. However, the presence of subsidence did not affect the radiologic and clinical outcomes. When the T1 slope was large and the C27 Cobb angle change was severe, more subsidence occurred.

We discuss the results of gravimetric and satellite geodetic measurements at the Zapolyarnoye and Yamburgskoye gas and oil deposits in Transpolar Western Siberia in subarctic zone of Yamal-Nenets autonomous okrug. The development of mineral deposits and large number of pipelines require monitoring of recent motions of the Earth’s surface. Displacements and other phenomenon were studied by satellite geodesy and absolute gravimetry. It is now possible to obtain the kinematic parameters (rates of subsidence and horizontal motion) and addition information on fluid motion into the layers of the deposits. The ground displacements rate in different short periods recorded at large man-made objects are shown. Rates for hydroobjects are estimated at 5 mm/yr. The gravimetry and satellite geodesy results obtained at the Zapolyarnoye deposit in the northern part of Western Siberia were analyzed. Subsidence rates of 21–23 mm/yr were estimated. An increase in gravity of up to 7 µGal were recorded at the deposits (2006–2008). In this case, the increased gravity is related to surface subsidence (with a normal vertical gradient). Subsidence rates of 16–21 mm/yr were estimated at the Yamburgskoye field. This result is consistent with the rates at Zapolyarnoye. The horizontal rates and orientation differed at different deposits.

Overall amount and quality of seeds reaching the area is an important factor in the development of plant communities in each habitat. It can be a significant source of diversity in anthropogenically disturbed areas. This study is focused on the survey of seed rain in habitats of waterlogged subsidence basins of the Karvina region, induced by deformations of overlying rocks in the area of deep coal mining. The density, species composition and dispersal strategies of captured seeds were monitored using funnel traps with a 35 cm diameter, fixed at a height of 0.5 m. A vegetation study was conducted to compare seed rain with above-ground vegetation using the Jaccard similarity index. Over 11 000 seeds of 27 plant species were captured in total. Seed rain was dominated by Salix alba species. Seed density varied significantly within individual sampling plots (7–12380 seeds/m2) with the average richness of four species. The diversity of above-ground vegetation was also low, with an average of 15 species per plot (100 m2). Similarity between seed rain and above-ground vegetation of subsidence basins is 27.6 % and 52 % within the woody species community. It is evident that the seed rain of waterlogged subsidence basins contains species of floodplain forests and wetland vegetation. On the other hand, invasive and expansive species identified both in seed rain and above-ground vegetation can potentially endanger the development of the succession of these habitats. The analysis of seed dispersal also shows a significant proportion of species of arid and mesic habitats. Keywords: Dispersal strategy; Karvina; Seed rain; Subsidence basin.

During strong El Niño events, below-average rainfall is expected in large parts of southern Africa. The 1992 El Niño season was associated with one of the worst drought episodes in large parts of South Africa. Using reanalysis data set from NCEP-NCAR, this study examined circulation types (CTs) in Africa south of the equator that are statistically related to the El Niño signal in the southwest Indian Ocean and the implication of this relationship during the 1992 drought episode in South Africa. A statistically significant correlation was found between the above-average Nino 3.4 index and a CT that features widespread cyclonic activity in the tropical southwest Indian Ocean, coupled with a weaker state of the south Indian Ocean high-pressure. During the analysis period, it was found that the El Niño signal enhanced the amplitude of the aforementioned CT. The impacts of the El Niño signal on CTs in southern Africa, which could have contributed to the 1992 severe drought episode in South Africa, were reflected in (i) robust decrease in the frequency of occurrence of the austral summer climatology pattern of atmospheric circulation that favors southeasterly moisture fluxes, advected by the South Indian Ocean high-pressure; (ii) modulation of easterly moisture fluxes, advected by the South Atlantic Ocean high-pressure, ridging south of South Africa; (iii) and enhancement of the amplitude of CTs that both enhances subsidence over South Africa, and associated with the dominance of westerlies across the Agulhas current. Under the ssp585 scenario, the analyzed climate models suggested that the impact of radiative heating on the CT significantly related to El Niño might result in an anomalous increase in surface pressure at the eastern parts of South Africa.

Stem subsidence is a known cause of early failure in cementless total hip arthroplasty (THA). The aim of this study was to determine the usefulness of pneumatic femoral broaching in preventing post-operative subsidence of a proximally porous-coated, taper-wedge stem. We reviewed 169 cases of primary THA with a single taper-wedge stem. Eighty THAs performed using pneumatic broaching were compared with 89 THAs performed using manual broaching in terms of postoperative canal fill ratio (CFR) at three levels, stem subsidence at one year post-operation, and stem fixation at latest follow-up (median, 24 months). The median CFRs were higher in the pneumatic group than in the manual group at all levels (p

Leaf chlorophyll content is an important indicator of crop growth. In coal mine areas with high phreatic level, crop damage caused by coal mining subsidence will inevitably lead to changes in leaf chlorophyll content. Therefore, accurate estimation of the chlorophyll content of winter wheat in subsidence areas of coal mines with high phreatic level can effectively identify the extent of cultivated land damage. In this study, based on the high-resolution unmanned aerial vehicle (UAV) visible-band image and ground sampling data obtained in April 2018, the chlorophyll estimation model of winter wheat in the subsidence area was established. By comparing and analyzing the spectral characteristics of the ground features in 3 visible-bands, the visible-band vegetation index suitable for estimate wheat chlorophyll content is selected for inversion. The results show that the accuracy of the single index, single variable estimation model is relatively low. Owing to the absence of multicollinearity, the proposed multivariate model-combined visible-band vegetation index (CVVI) based on combination index 2 (COM2), visible-band difference vegetation index (VDVI) and red–green–blue vegetation index (RGBVI) has high inversion accuracy. The reliability and effectiveness of the CVVI estimation model are verified by samples. The coefficient of determination (R2), the root mean square error (RMSE) and the normalized root mean square error (NRMSE) are 0.639, 1.750 and 0.196, respectively. This indicates that the estimation model is relatively stable. A chlorophyll map is developed based on estimation using the proposed model. According to the results, the overall chlorophyll content of wheat in the subsidence area is relatively low and chlorophyll is mainly concentrated in 22–44 SPAD (soil and plant analyzer development), which accounts for 80.1% of the cultivated land area. This study indicates that the wheat in the study area is affected by coal mining disturbances to varying extents. The formation of slope land and stagnant water areas reduces the productivity of cultivated land and leads to severe damages on cultivated land. This study provides a methodology for estimations of growth index of crops in the subsidence area of coal mine with high phreatic level.

The impact of vertical resolution on the simulation of Typhoon Lekima (2019) is investigated using the Weather Research and Forecasting (WRF) model version 3.8.1. Results show that decreasing vertical grid spacing from approximately 1000 m to 100 m above 1 km height barely influences the simulated track. However, significant differences are found in the simulated tropical cyclone (TC) structure. The simulation with the coarsest vertical resolution shows a clear double warm-core structure. The upper warm core weakens and even disappears with the increase of vertical resolution. A broader eye and a more slantwise eyewall are observed with the increase of vertical resolution due to the vertically extended lower-level and upper-level outflow, which likely results in a weaker subsidence. Vertical grid convergence is evaluated with the simulated kinetic energy (KE) spectra. As the vertical grid spacing becomes finer than 200 m, convergent KE spectra are found in both the free atmosphere and the outer core of the TC. However, sensitivity tests reveal that the grid convergence is sensitive to the choice of the planetary boundary layer scheme.

Using cementless stems in total hip arthroplasty (THA) has revealed variable results. The risk for early aseptic loosening has been associated to certain surgical approaches and implant designs. This study determines misalignment of collared/collarless stems and the rate of subsidence using the anterolateral approach (ALA) compared to implantations via the direct lateral approach (DLA). One hundred consecutive patients underwent primary unilateral THA using the minimal invasive ALA in the lateral decubitus position and were compared to another cohort of 100 patients, treated trough the DLA. Clinical results were noted preoperatively and after 1 year using the WOMAC score. The radiographic evaluation included the stem alignment and subsidence. Overall, all patients improved in WOMAC from 48.9 points (± 11.4; 21.0–82.0) to 3.1 (± 3.2; 0.0–22.0) (p

Aim: Understanding how biotic communities are spatially distributed is essential for biodiversity conservation in human-modified landscapes. The large-scale subsidence wetlands generated by underground coal mining in China have been increasingly used by large numbers of waterbirds, which remain understudied. We aimed to explore the role of non-random assembly in shaping the regional waterbird diversity in non-breeding seasons, providing insights for the conservation. Location: The North China Plain. Methods: Taxonomic β-diversity and functional β-diversity (both multiple-site and pairwise) of the waterbird communities were quantified and decomposed into turnover (i.e. species replacement) and nestedness components (i.e. the poorer sites being subsets of the richer sites). Observed functional α-diversity and pairwise β-diversity, as well as the two components, were compared with simulated means under random assembly processes in null models, which maintained the species richness, pairwise taxonomic dissimilarity, and its turnover and nestedness components as the observed. Results: The communities exhibited similar multiple-site taxonomic and functional β-diversity, which were primarily contributed by taxonomic and functional turnover, respectively. The pairwise functional β-diversity, as well as its turnover and nestedness components, was positively correlated with their taxonomic counterparts. The pairwise functional β-diversity was higher than the taxonomic β-diversity, with the former mainly reflecting nestedness of functional strategies and the latter reflecting species replacement. The observed functional α-diversities in most communities were lower, and most of the observed pairwise functional β-diversities were higher than the simulated means in null models. Main conclusions: The above patterns suggest the existence of non-random assembly of the waterbird communities across the subsidence wetlands. To protect waterbirds in the subsidence wetlands, we suggest that most wetlands should be protected via increasing habitat diversity. Furthermore, considering the changing environmental conditions, changes in the multiple biodiversity metrics should be monitored to inform the ongoing management plans.

Ground subsidence is regarded as one of the most common geohazards, accompanied with the rapid urban expansion in recent years. In the last 2 decades, Wuhan, located in the alluvial Jianghan Plain, has experienced great urban expansion with increased subsidence issues, i.e., soft foundation subsidence and karst collapse. Here we investigated subsidence rates in Wuhan with 2015–2019 Sentinel-1 synthetic aperture radar (SAR) images. We found that the overall subsidence over the Wuhan region is significantly correlated with the distribution of engineering geological subregions (EGSs). We further validated the interferometric SAR (InSAR) measurements with better than 5 mm accuracy by comparing with leveling measurements. Subsidence centers in Qingling–Jiangdi, Houhu, Qingshan, and Dongxihu were identified with displacement rates of approximately 30 mm/yr. Our results demonstrated that the dominant driving factor is ongoing construction, and the fact that the subsidence centers shifted with construction intensities. The Qingling–Jiangdi area in our study is a well-known site of karst collapse. We find that the nonlinear subsidence of this area is correlated with the seasonal rainfall.

Purpose Uncemented stem migration analysis by EBRA-FCA (Einzel-Bild-Roentgen Analyse, Femoral Component Analyse) has been seen to be a good predictive indicator for early implant failure. In this study, we investigated the migration behavior of a cementless metaphyseal-anchored press-fit stem after 4-year follow-up. Methods Applying a retrospective study design, we reviewed all consecutive patients who between 2012 and 2017 received a cementless Accolade II press-fit stem at our Department. We reviewed medical histories and performed radiological measurements using EBRA-FCA software. EBRA-FCA measurements and statistical investigations were performed by two independent investigators. Results A total of 102 stems in 91 patients (female 60; male 31) fulfilled our inclusion criteria. Mean age at surgery was 66.2 (range 24.3–92.6) years. EBRA migration analysis showed a mean subsidence of 1.4 mm (range 0.0–12.0) at final follow-up. The angle between stem and femur axis was 0.5° (range 0.0°–2.8°) after 48 months. No correlations between gender or Dorr types and subsidence were found (p > 0.05). A body mass index > 30 kg/m2 showed a significant increase in stem subsidence within the first 6 (p = 0.0258) and 12 months (p = 0.0466) postoperative. Conclusions Migration pattern of the metaphyseal-anchored stem and a low subsidence rate at final follow-up may predict a good long-term clinical result. Trial registration Number: 20181024-1875.

Most of the coal mining in China is underground, which will inevitably cause surface deformation and trigger a series of geological disasters. Therefore, it is essential to find a suitable method to forecast the ground sinking caused by underground mining. The most commonly used prediction model in China is the probability integral model (PIM). But when this model is used in the geological condition of mining under thick loose layers, the predicted edge of the sinking basin will converge faster than the actual measured sinking situation. A geometric model (GM) with a similar model shape as the PIM but with a larger boundary value was established in this paper to solve this problem. Then an improved cuckoo search algorithm (ICSA) was proposed in this paper to calculate the GM parameters. The stability and reliability of the ICSA were verified through a simulated working face. At last, the ICSA, in combination with the GM and the PIM, was used to fit 6 working faces with the geological mining condition of thick loose layers in the Huainan mining area. The results prove that GM can solve the above-mentioned PIM problem when it is used in geological mining conditions of thick loose layers. And it was obtained through comparative analysis that the GM and the PIM parameters can take the same value except for the main influence radius.

The purpose of this study is to analyze the dynamic/thermodynamic features of the center and periphery of upper tropospheric cyclonic vortices (UTCV) in Northeast Brazil (NEB). An algorithm was developed to identify the vortex climatology using ERA-Interim, while rainfall impact was assessed using the Climate Prediction Center dataset, from 1980 to 2016. The algorithm was validated by comparison UTCV’s positions obtained by subjective analysis, showing good performance regarding positioning and seasonality. One of the preferential regions of UTCV occurrence was the semiarid region of NEB, which may indicate these systems have a strong influence on the water deficit in the region. Air subsidence and mass divergence at the center and upward motions and convergence on the periphery of the system were observed. Two conceptual skew-t diagrams were generated and the results bring a new perspective about UTCV thermodynamic features, some of which are: in the center, associated with subsidence, low convective available potential energy (CAPE) values and low humidity concentration were detected in a large atmospheric layer due to the subsidence generated by mass convergence at high levels. In contrast, the edge region presented high CAPE values and high atmospheric moisture content, related to the mass convergence in lower troposphere. The advances in knowledge about dynamic/thermodynamic characteristics of this meteorological system generate perspectives for better simulations, improving its predictability. In addition, the proposed algorithm is of great value for future climatological studies of UTCV.

This study aims to compare the early subsidence rate (6–12 months) of standalone novel 3D-printed titanium (Ti) versus polyetheretherketone (PEEK) interbody cages after lateral lumbar interbody fusion (LLIF). A retrospective study of 113 patients (186 levels) who underwent LLIF surgery with Ti or PEEK cages was conducted. Early subsidence was measured in each treated level using the Marchi et al. classification in radiographs or CT scans acquired at 6–12 months follow-up. Multivariate logistic regression analyses with generalized mixed models, setting subsidence as the outcome variable and including cage type (Ti vs PEEK) as well as significant and trending variables (p

Subarctic peatlands underlain by permafrost contain significant amounts of organic carbon. Our ability to quantify the evolution of such permafrost landscapes in numerical models is critical for providing robust predictions of the environmental and climatic changes to come. Yet, the accuracy of large-scale predictions has so far been hampered by small-scale physical processes that create a high spatial variability of thermal surface conditions, affecting the ground thermal regime and thus permafrost degradation patterns. In this regard, a better understanding of the small-scale interplay between microtopography and lateral fluxes of heat, water and snow can be achieved by field monitoring and process-based numerical modeling. Here, we quantify the topographic changes of the Šuoššjávri peat plateau (northern Norway) over a three-year period using drone-based repeat high-resolution photogrammetry. Our results show thermokarst degradation is concentrated on the edges of the plateau, representing 77 % of observed subsidence, while most of the inner plateau surface exhibits no detectable subsidence. Based on detailed investigation of eight zones of the plateau edge, we show that this edge degradation corresponds to an annual volume change of 0.13±0.07 m3 yr−1 per meter of retreating edge (orthogonal to the retreat direction). Using the CryoGrid3 land surface model, we show that these degradation patterns can be reproduced in a modeling framework that implements lateral redistribution of snow, subsurface water and heat, as well as ground subsidence due to melting of excess ice. By performing a sensitivity test for snow depths on the plateau under steady-state climate forcing, we obtain a threshold behavior for the start of edge degradation. Small snow depth variations (from 0 to 30 cm) result in highly different degradation behavior, from stability to fast degradation. For plateau snow depths in the range of field measurements, the simulated annual volume changes are broadly in agreement with the results of the drone survey. As snow depths are clearly correlated with ground surface temperatures, our results indicate that the approach can potentially be used to simulate climate-driven dynamics of edge degradation observed at our study site and other peat plateaus worldwide. Thus, the model approach represents a first step towards simulating climate-driven landscape development through thermokarst in permafrost peatlands.

Duplication of circuit breakers (CBs) in substations is not realistic due to economic and operational constraints. In the event of failure of a CB, adjacent breakers need to be called in to isolate the fault. Typically, a breaker-failure protection (BFP) function is integrated within commercial relays to monitor such situations. However, these functions are prone to maloperation because of subsidence in current transformers (CTs) resulting from faults with significant decaying dc component. To this end, a reliable reset algorithm for the BFP function is presented. After measuring the decaying dc component within a one-cycle moving window, the proposed algorithm accurately distinguishes between the alternating pattern of fault current and exponential decaying pattern in subsidence current. Its performance remains unaffected during change in fault current level, decaying dc component, CT saturation, level of subsidence, and random noise. Effectiveness of the proposed scheme in practical scenarios is demonstrated through a hardware setup validated through error analysis. Overall performance evaluation in terms of reliability indices testifies its superiority over available techniques.

Compared with traditional measurement technologies, synthetic aperture radar interferometry (InSAR) has unique advantages in monitoring ground subsidence due to underground mining. However, when the subsidence gradient of the subsidence trough exceeds the maximum measurable gradient of InSAR technology, the interference fringes will be too dense, causing phase aliasing. As a result, it is impossible to obtain correct phase-unwrapping result. The main objectives of this letter are two folded. First is to develop an unwrapping strategy to deal with the unwrapping problem caused by large subsidence gradient at the mine subsidence trough. The main idea of this strategy is to estimate most of the subsidence phase by multiple model inversions based on iterative approach. Then, the model phases from multiple models are combined with the final unwrapped residual phase. Another objective of this letter is to evaluate the feasibility of the three common deformation models, i.e., Mogi, probability integral method (PIM), and Okada, in solving the phase-unwrapping problem. Their advantages and disadvantages are outlined. Both the simulated data and real data are used for this experiment. The result shows that the problem of large subsidence gradient in the differential interferometric synthetic aperture radar (DInSAR) results can be solved by multiple model inversion. Among the three models, the use of Okada model seems to provide slightly more accurate result for solving the large-scale subsidence in the mining area than the other two models with the proposed strategy.

This paper uses two subsets of ensemble historical-Nat simulations and pi-Control simulations from CMIP5 as well as observational/reanalysis datasets to investigate responses of the tropical Pacific to the 11-yr solar cycle. A statistically significant 11-yr solar signal is found in the upper-ocean layers above the thermocline and tropospheric circulations. A warming response initially appears in the upper layers of the central equatorial Pacific in the solar maximum years in observations, then increases and shifts into the eastern Pacific at lagged 1–3 yr. Meanwhile, an anomalous updraft arises over the western equatorial Pacific and shifts eastwards in the following years with anomalous subsidence over the Maritime Continent. These lagged responses are confirmed by the historical-Nat simulations, except that the initial signal is located more to the west and all the responses are weaker than the observed. A simplified mixed-layer heat budget analysis based on the historical-Nat simulations suggests that the atmospheric forcing, especially the shortwave radiation, is the major contributor to the initial warming response, and the ocean heat transport effect is responsible for the eastward displacement of the lagged warming responses. In the solar maximum years, the zonal ocean temperature gradient in the western–central Pacific is reduced by the initial warming, and anomalous westerly winds appear over the western equatorial Pacific and extend into the eastern Pacific during the lagged years. These anomalous westerly winds reduce the wind-driven ocean dynamical transport, resulting in the initial warming in the central equatorial Pacific being amplified and the surface warming shifting eastward during the lagged 1–3 yr.

Underground mining causes terrain surface deformations that lead to various threats to the environment and people, thus a systematic deformation monitoring needs to be performed. This monitoring mainly focuses only on the vertical part of the deformation and remote sensing techniques are currently very often used for this purpose. The development of Unmanned Aerial Systems (UASs) open new possibilities in this context. Most commonly, the mapping UASs are equipped with RGB cameras but also other lightweight sensors are utilized. In this work, the usefulness of UAS photogrammetry and LiDAR data is investigated in the context of detection and measurement of terrain deformations caused by underground mining. The accuracy of the methods was compared in reference to TLS data. The UAS and TLS measurements were performed in 2018 and 2019 but the subsidence was also evaluated in regards to ALS data acquired in 2011. The standard methodology based on Digital Terrain Models of Difference (DoDs) was applied to detect the subsidence. The DoD analysis was restricted to the hard surfaces. The profiles along the roads were also analysed to validate the accuracy of the data. The analysis showed that the UAS photogrammetry enables to obtain less noisy data and more accurate results of the terrain subsidence measurement than the UAS LiDAR sensors. The comparison of the DoDs showed about 33 cm subsidence between 2011 and 2018, which gives a subsidence rate of about 5 cm/year. The observed subsidence between years 2018 and 2019 was equal to about 5 to 15 cm depending on the measurement technique and investigated area.

Under the background of global warming, the summer temperature of the North and Northeast China (NNEC) has significantly increased since 2017, which was accompanied by the aggravated ozone (O3) pollution. In 2018, the NNEC experienced a record-breaking summer of the past 40 years. Influenced by the abnormal high temperatures, a regional ozone event occurred on 2-3 August, over 63% of 79 selected cities in the NNEC were exposed to O3 pollution, and the maximum value of MDA8 O3 reached 268 μg/m3. Observations indicated that ozone concentrations agree well with the maximum temperature at 2 meters (MT2M) over NNEC with a correlation coefficient of 0.69. During the pollution episode, strong downdraft in the local high (35°N-42.5°N, 112.5°E-132.5°E; LH) over the NNEC created the favourable meteorological conditions for O3 formation. By analyzing the horizontal wind and wave activity fluxes (WAFs) at 200 hPa, we found that the LH formation was resulted from the Rossby wave propagation from upstream along the mid-latitude Asian jet. The split polar vortex intrusion further strengthened the amplitude of the Rossby wave and reinforced the LH. Moreover, a secondary circulation between Typhoon Jongdari and the LH contributed to the enhanced LH with strong subsidence. On the other hand, the stratospheric intrusions under the deep subsidence also contributed to the enhanced surface O3. In this study, the deep-seated meteorological dynamical mechanisms contributing to the abnormal high temperatures were investigated, which can lead to a better understanding of the regional O3 pollution over NNEC under the global-warming background.

Subsidence monitoring is an important means to ensure the safety of buildings. After subsidence monitoring, it is necessary to mine key information from the monitored information, interpret the subsidence through in-depth analysis of the information, and predict the subsidence of buildings, especially the residential buildings. To improve the accuracy of subsidence interpretation and prediction, this paper applies the tracking fusion Kalman filtering algorithm to process the building subsidence monitoring data. Tracking fusion algorithm is a global suboptimal weighted state fusion algorithm. This algorithm not only can significantly improve the local estimation error, but also has the advantages of small computational burden and good fault tolerance, which is very convenient for practical engineering application. The simulation results show that the proposed tracking fusion Kalman filtering algorithm outperformed the local Kalman filtering algorithm adopted by Deng et al. in estimation accuracy of building subsidence. The research results provide reference for the protection of building safety.

In this study, an improved Knothe time function model is established via analogical reasoning from a phenomenological perspective, based on an inverse “Hohai creep model” function, in accordance with the antisymmetric relationship between the unstable creep curve and surface dynamic subsidence curve. An empirical method and fitting method are proposed to determine the parameters of the improved model based on the availability of measured field data. The accuracies of the two models are compared with monitored data from eight monitoring points in the main strike profile of the Guotun coal mine subsidence basin. The results show that the improved model can more accurately reflect the dynamic process of surface subsidence. The average relative standard deviation of the improved model is only 4.9%, which is far lower than the 23.1% associated with the Knothe model. This verifies the improved model’s accuracy and reliability. The model parameters for different monitoring stations obtained using the fitting method are similar, which shows that the model parameters are regular and can be easily applied.

Northeast Brazil (NEB) is usually affected by droughts, most of them connected with El Nino. In this context, the aim of this study is to investigate and update the different dynamical aspects of atmosphere and surface ocean associated with the recent strong El Nino events (1982–1983, 1997–1998, and 2015–2016) and their effects on rainfall over NEB. Here, we show that dry years were observed in NEB during all strong El Nino events analyzed. By analyzing the spatial distribution of rainfall in the wet season (February–May), we found that the highest water deficits were observed in northern Northeast Brazil (NNEB), with the most intense anomalies occurring during the 1982–1983 and 1997–1998 events. These anomalies were associated mainly with the distribution of sea surface temperature (SST) anomalies that during the 1982–1983 and 1997–1998 events presented stronger warming in the eastern Pacific, while in 2015–2016 occurred in the western and central equatorial Pacific. These oceanic conditions modulated the atmospheric circulation pattern and led to three different dynamical aspects. Thus, the drought of 1982–1983 was attributed to strong subsidence caused by the Walker and Hadley cells, while in 1997–1998, in addition to this subsidence, the anomalous 200 hPa cyclone near NNEB also caused sinking motion. In 2015–2016, combined with the subsidence induced by the Walker and Hadley cells, an atmospheric pattern similar to the Pacific–South American/South Pacific Convergence Zone seems to have contributed to intensification of downward motion over NEB, indicating an influence of Rossby wave train.

Permafrost is an important part of the cryosphere, playing an integral role in the hydrologic cycle, ecology, and influencing human activity. Melting of ground ice can drastically change landscapes and associated thaw subsidence may induce instability of infrastructure. The terrain conditions on the Qinghai-Tibet Plateau are complex, and the spatial distribution of ground ice is highly variable, so knowledge of its abundance and variability is required for impact assessments relating to the degradation of permafrost. This study examined 55 permafrost samples from warm, ice-rich permafrost region in Beiluhe Basin, Qinghai-Tibet Plateau. The samples were examined using Computed Tomography scanning, and the ice content and cryostructure were determined. The results indicated that: 1) variation in volumetric ice content was considerable (0%–70%), with a mean value of 17%; 2) seven cryostructures were identified, including crustal, vein, lenticular, ataxitic, reticulate and layered cryostructure; 3) volumetric ice content varied by cryostructure, with the highest associated with layered and ataxitic cryostructures. Volumetric ice contents were lowest for samples with pore and lenticular cryostructures. This work provides detailed ground ice content and will be helpful for assessing thaw subsidence and infrastructure stability on Qinghai-Tibet Plateau.

The literature was reviewed to establish the levels of stem subsidence for both double and triple-tapered implants in order to determine whether there were any differences in subsidence levels with regard to the methods of measurement, the magnitude and rate of subsidence and clinical outcomes. All studies reporting subsidence of polished taper-slip stems were identified. Patient demographics, implant design, radiological findings, details of surgical technique, methods of measurement and levels of subsidence were collected to investigate which factors were related to increased subsidence. Following application of inclusion and exclusion criteria, 28 papers of relevance were identified. The studies initially recruited 3090 hips with 2099 being available for radiological analysis at final follow-up. Patient age averaged 68 years (42–70), 60.4% were female and the average body mass index (BMI) was 27.4 kg/m2 (24.1–29.2). Mean subsidence at one, two, five and 10 years was 0.97 mm, 1.07 mm, 1.47 mm and 1.61 mm respectively. Although double-tapered stems subsided more than triple-tapered stems at all time points this was not statistically significant (p > 0.05), nor was the method of measurement used (p > 0.05). We report the levels of subsidence at which clinical outcomes and survivorship remain excellent, but based on the literature it was not possible to determine a threshold of subsidence beyond which failure was more likely. There were relatively few studies of triple-tapered stems, but given that there were no statistically significant differences, the levels presented in this review can be applied to both double and triple-tapered designs. Cite this article: EFORT Open Rev 2021;6:331-342. DOI: 10.1302/2058-5241.6.200086

Northeastern US heat waves have usually been considered in terms of a single circulation pattern, the high-pressure circulation typical of most heat waves occurring in other parts of the world. However, k-means clustering analysis from 1980–2018 shows there are four distinct patterns of Northeast heat wave daily circulation, each of which has its own seasonality, heat-producing mechanisms (associated moisture, subsidence, and temperature advection), and impact on electricity demand. Monthly analysis shows statistically-significant positive trends occur in late summer for two of the patterns and early summer for a third pattern, while the fourth pattern shows a statistically significant negative trend in early summer. These results demonstrate that heat waves in a particular geographic area can be initiated and maintained by a variety of mechanisms, resulting in heat wave types with distinct impacts and potential links to climate change, and that pattern analysis is an effective tool to distinguish these differences.