Variation In Level Research Articles

Spatiotemporal variation of water level in wetlands based on multi-source remote sensing data and responses to changing environments

Under changing environmental conditions, water level is a crucial indicator for assessing the wetland hydrological cycle. However, due to some wetlands being located in remote and widely dispersed areas, acquiring data on wetland water level changes presents significant challenges, making wetland water level monitoring exceptionally difficult. Wetlands are extensively distributed in western Jilin Province, China, and are experiencing significant degradation due to various factors including natural conditions, agricultural activities, and social development. To address this challenge, this study proposes a monitoring method that combines Sentinel-3 radar altimetry satellites with optical remote sensing images to obtain wetland water level data. Additionally, the study takes into account the Chinese government's Interconnected River System Network Project (IRSNP), classifying wetlands in western Jilin Province into three different water recharge scenarios: direct recharge through main and branch canals, indirect recharge through ditches, and no recharge to isolated wetlands. This study analyses the relationship between wetland water level changes and climatic factors, and assesses how IRSNP can mitigate the negative impacts of climate factors on wetland water levels across different recharge scenarios. The results show that: (1) the wetland water level monitoring method, has high accuracy and feasibility. The average difference between the in-situ measured and satellite-monitored water levels was 0.254 m. (2) There was an overall increasing trend in wetland water levels directly influenced by IRSNP, an insignificant decreasing trend in wetland water levels indirectly influenced by IRSNP. (3) Increased precipitation and decreased evaporation are the predominant climatic factors contributing to rising wetland water levels. Conversely, lower relative humidity and higher temperatures primarily lead to declining water levels. The construction of IRSNP can mitigate the impact of climate change on water levels. Thus, under changing environmental conditions, the implementation of IRSNP has positively impacted wetland protection and provides valuable insights for understanding wetland water level changes and managing water resources effectively.

A methodology for assessing multiple hazards applied to Sweden

Despite extensive efforts through various international initiatives to reduce global warming, it has been determined that human induced climate change is here, that the present scale of disruption of the climate is unprecedented and will continue. Increasing weather volatility can be expected, which will most likely increase exposure to weather related hazards, e.g. wildfires, flooding. The aim of this paper is to present an index-based multi-hazard risk assessment method to assess wildfires and flooding hazard for two municipalities within Sweden. The method is designed to be used by the Fire and Rescue Service (FRS) for planning purposes and can be modified to take the local FRS’s capabilities and local conditions into account, thereby improving hazard preparedness at a local level. The analysis presented indicates that, while the frequency of multi-hazard overlap from wildfires and flooding is greatest in more northern parts of Sweden, the method provides important information even when applied to areas with limited overlap. A variation of the hazard assessment using a box kernel sliding window was studied to investigate the sensitivity of the model for rapid variations of an individual hazard level. Given that resource needs will typically spread over several days for large scale natural hazards, the box kernel approach is valuable in helping to identify a span of days when resources associated with incident response might be needed. In the future, the model should be expanded to include additional single hazards, the application to additional municipalities and extension to FRS planning exercises for natural hazards.

Seasonal variation in serum cholesterol level in perimenopausal women: A preliminary research

Seasonal variation in serum cholesterol level in perimenopausal women: A preliminary research

Estimation of Denudation Parameters and River Capture Events From Neural Network Inverse Modeling of River Profiles and Thermo‐ and Geochronology Data

AbstractEarth's topography represents the cumulative effects of tectonics and surface processes modulated by climate and lithology. These factors shape landscapes through time. River profiles can be inverted to estimate the rock uplift histories or lithology‐specific erodibilities. However, river systems are dynamic and evolve in response to spatial and temporal internal dynamics, such as river capture events. Here, we present a modeling framework to infer denudation rates from the inversion of river profiles and thermo‐ and geochronology data. We achieve this by coupling a landscape evolution model and an efficient inverse modeling scheme to infer poorly resolved erosional and tectonic parameters. An application of the approach is presented for the Neckar catchment, southwest Germany, characterized by stark lateral variation in bedrock erodibility and rock uplift, and that have demonstrably undergone multiple river capture events. Different end‐member scenarios are explored in the simulations. First, we test uniform and spatial variability in rock uplift rate and bedrock erodibility, and second, temporal variations in rock uplift rate and base level. Finally, we simulate river capture events by adding upstream sections (drainage area) at specific times and locations within the fluvial network. We find that spatial variation in rock uplift rate is necessary to reproduce the Neckar's river profile while honoring analytical observations. Simulations integrating river captures allow improved river profile predictions of specific tributaries of the Neckar catchment, leading to potentially more realistic erodibility and rock uplift history estimates. The time and location of the capture events determined from the modeling agree with previous estimations from geological evidence.

An observational study on variations of serum uric acid level in patients of depression and healthy controls and its correlation with hidden bipolarity

Background: Bipolar disorder (BD) is one of the most studied psychiatric disorders, this being one of the leading causes of disability in young individuals. In search for its predictive biomarker, serum uric acid (UA) level was seen to have a pathophysiologic role in the genesis of BD through oxidative stress and other mechanism. Aims and Objectives: The aim of the study was to estimate serum UA levels in patients with 1st episode depression, to compare serum UA levels between patients and matched healthy controls and to compare serum UA levels between patients with and without hidden bipolarity and therefore, and to evaluate whether it can be used as a predictor of bipolarity. Materials and Methods: A study was conducted in a tertiary care center in Eastern India for a duration of 3 months with a sample size of 92, comprising 46 cases with major depressive disorder (MDD) and 46 control groups of healthy subjects. Their serum UA levels were estimated. The study population was subjected to a mood disorder questionnaire (MDQ) and Montgomery–Asberg Depression Rating Scale (MADRS) scoring. All these data were tabulated in a master sheet and analyzed using Statistical Packages for the Social Sciences 25 software. Results: The mean age of the study population was 32 years with 46 males and 46 females. The mean UA levels for MDD group was 5.27±1.14 mg/dL and for control group was 4.6±1.2 mg/dL, which was seen to be statistically significant (P=0.001). No statistically significant association was seen between the group with a high likelihood of bipolarity versus a low chance of bipolarity with respect to UA levels. A positive correlation was seen between MDQ scores and UA levels of depressed individuals (using Spearmen’s rho: rs=0.345, P=0.019), but not with their MADRS scores. Conclusion: Serum UA levels are significantly higher in depressed patients as compared to healthy subjects. A non-statistical association was seen between UA levels and their bipolar tendencies, owing to a small sample size of comparable groups. However, a higher MDQ score was associated with high UA levels. A larger study population is needed to conclusively establish the predictive role of UA with respect to BD.

Association between fluctuations in blood cholesterol levels and the risk of suicide death in the general population

ObjectiveSuicide is a pressing global public health issue. While recent studies have explored the association between serum cholesterol levels and suicide risk, the association between cholesterol variability and suicide risk is not well characterized. MethodsThis was a nationwide population-based cohort study using data from the Korean National Health Insurance Service database. A total of 1,983,701 patients with at least three measurements of TC between 2004 and 2009 were included. Participants were followed until death by suicide or the study's end in December 2021. Participants were categorized based on baseline TC or TC variability. TC variability was assessed using coefficient of variation (CV), variability independent of the mean (VIM), and average successive variability (ASV). ResultsOver a median follow-up of 11 years, 5883 (0.3 %) patients died by suicide. Compared to subjects with TC <200 mg/dL, those with TC ≥240 mg/dL had a lower risk of suicide death (hazard ratio [HR]: 0.85, 95 % confidence interval [95 % CI]: 0.78–0.93). In the unadjusted model, the HR for suicide death in the highest quartile (Q4) compared to the lowest quartile (Q1) of TC variability was 1.36 (95 % CI: 1.26–1.46). After adjusting for potential confounders, high variability in TC level was associated with a higher risk of suicide death (HR 1.27, 95 % CI: 1.18–1.37). When analyzed based on the combination of TC baseline and variability, the highest quartile of TC variability showed a higher rate of suicide death compared to the lowest quartile, regardless of baseline TC level. ConclusionHigh TC variability and low TC levels were associated with an increased risk of suicide.

Seismic stratigraphy and petroleum prospectivity in the Northern Rovuma Basin, offshore Tanzania

The upper slope area of the Northern Rovuma Basin has been poorly studied and little is known about its development and petroleum prospectivity. Interpretation of wellbore, 2D and 3D seismic reflection data in this area has allowed identification of seismic features reflecting key factors for understanding the development of the Cretaceous-Holocene stratigraphy and distribution of petroleum system elements. Our results show that infill of sediment into the basin was due to an interplay of three major factors. These are the sea level variations, extensional tectonics and sediment gravity flows. The Miocene and Pleistocene-Holocene tectonic events triggered gravity flows that supplied sediments to the basin. The resultant deposits include slides, slumps, debrites and turbidites some of which contain potential reservoirs that are interpreted to have been charged by the Permo-Triassic Karoo shales and Cretaceous-Cenozoic source rocks. These reservoirs are contained in both stratigraphic and structural traps with localized combinations in some places, and are encased by deep marine shales. Some of the potential reservoirs are positively inverted and compartmentalized, and they contain several bright and flat spots suggesting hydrocarbon accumulations within the Miocene and Oligocene intervals. It has also been revealed that major gravity flows and bottom currents, that supplied and distributed sediment to the basin, were confined in three long-lived channelized systems that were initiated during the Cretaceous (due to rapid regression), and the Oligocene and Pleistocene periods (due to rapid uplift). The channels migrated toward the southeast, with some shift toward the northeast, and had overall northeast traverse direction perpendicular to the shoreline. The reported gravity flows eroded previously deposited sediment in most places causing several unconformities in the whole Cretaceous-Holocene stratigraphy. Seismic stratigraphic interpretation and facies analysis have proved useful in the identification of key petroleum system elements and improve understanding of sedimentary fill evolution of the study area.

Research on the hydraulic response characteristics during the water conveyance process of water diversion projects

Abstract During the initial trial period, the Hanjiang-to-Weihe River Valley Water Diversion Project (HWRVWD) sourced water from the Sanhekou water conservancy junction. It then transferred water through the Qinling water conveyance tunnel and distributed it at the Huangchigou water distribution hub, ultimately transporting it to the Guanzhong area. The hydraulic simulation and real-time control of the water conveyance system play a crucial role in ensuring the safe and efficient operation of this engineering project. To maintain water transfer safety and reasonable scheduling during the water supply process, the hydraulic characteristics of the transient process were calculated and analyzed in this paper. The one-dimension (1D) hydrodynamic mathematical model and advection-dispersion model were established to calculate the hydraulic factors of the 81.78 km Qinling water conveyance tunnel and the Huangchigou water distribution hub within the HWRVWD. Validation results showed that the root mean squared error tended toward zero and the coefficient of determination exceeded 0.97 between the measured values and the simulated values. The opening of gates and upstream inflow directly affected water level variations and storage. Smaller gate openings led to increased water level amplitudes before the gate and faster reaching of maximum water levels, but it also led to opposite trends in flow rates behind the gate compared to upstream water levels. The impact of incoming water flow rates on flow variations at different channel sections was significant. The time for water heads to reach each section and the rate of flow variation positively correlated with incoming water flow rates. Gradual increases in upstream inflow resulted in progressively larger water level amplitudes both before and behind the gate, with an increased maximum value, but more water might be discarded. When the water demand changes, the primary focus is on controlling the upstream inflow, with gate opening adjustments as a secondary measure, to achieve the goal of minimizing or eliminating water wastage.

Changes in Medication Adherence Across the Posttransplant Period in Pediatric Organ Transplant Recipients.

Limited research has explored immunosuppressant medication adherence over time in pediatric transplant patients, who often struggle with posttransplant regimen adherence, resulting in poor outcomes. This study investigated the longitudinal growth in immunosuppressive medication levels following transplantation. Medication level variability index (MLVI) scores from tacrolimus blood levels of pediatric organ transplant recipients at a major medical center were analyzed. Linear mixed effect models (LMEM) assessed individual MLVI change trajectories and predictors of growth, exploring both linear and curvilinear growth patterns posttransplant. A sample of 181 patients with at least 4 years of MLVI data were analyzed. Growth curve modeling identified the cubic model as the best fit for the quarterly MLVI values, which significantly decreased within the first 2 years posttransplant before stabilizing. Gender significantly predicted MLVI change, with females showing greater MLVI decreases, while age at transplant did not significantly predict changes. Significant variation in MLVI among individual patients was found in all models. The study demonstrated a significant decrease in MLVI values over time, indicating improved medication adherence in pediatric transplant patients, with females exhibiting more adherent growth patterns than males. Future research should aim to identify pediatric patients at high risk of nonadherence.

Interleukin 1β And Interleukin-6 and Some Oxidants in Patients With Stable Angina

ROS play an essential physiological roles in the cellular homoeostasis and cell signaling under normal circumstances. The overexpression of ROS was involved in the pathological events of several diseases, including cardiovascular, because they cause damage to many cell structures.This study aims to evaluate the levels of inflammatory biomarkers, [interleukin-6 (IL-6) and interleukin-1beta (IL-1β)] in stable angina patients and their relationship with oxidative stress. The current study is a case-control one performed on 88 patients with stable angina and 44 people as a control group attending the Nasiriyah Heart Center from August 2023 to March 2024. All cases were diagnosed by cardiologists and confirmed by laboratory investigations. Blood samples (10 ml) were collected from patients. Serum was isolated after centrifugation and stored at -20°C. Serum CK-MB, MYO and Trop I were determined by electro-chemiluminescence immunoassay. While, the ELISA was employed to assess the levels of human IL-6, human IL-1 β, SOD, (GSH-Px/ GPX), total cholesterol, triglycerides, LDL, VLDL and HDL, using the kits from Solarbio, China. The patients with stable angina didn’t show significant variation in the serum level of troponin I and CK-MB in comparison with control, while serum myoglobin level was significantly increased in patients with stable angina compared to control. Although the level of total cholesterol was insignificantly increased, but the levels of triglyceride (TG), VLDL-C and LDL-C were significantly increased, while the serum level of HDL-C was significantly declined in comparison with control. The serum levels IL-6 and IL-1β, in addition to activities of SOD and GPx were increased significantly in patients of angina compared to control. We could conclude that IL-1β, IL-6, SOD and GPx are increased in stable angina. Inflammatory events and oxidative stress could play an important roles in initiation of atherosclerosis and subsequent angina.

Interleukin one beta (IL-1B) gene polymorphisms in Iraqi patients with susceptibility to develop hepatitis C infections

Hepatitis C virus (HCV) infection is the main cause of chronic hepatitis, affecting an estimated 150 million people worldwide. Initial exposure to HCV is most often followed by chronic hepatitis, with only a minority of individuals spontaneously clearing the virus. This study aimed to find an associated relationship between HCV susceptibility and Polymorphic gene of IL‐1B targeting a total of 45 individuals: 30 patients with chronic hepatitis C and 15 healthy control from different cities of Iraqi recruited the Hospital for diseases of the digestive system and liver in Baghdad between November 2022 to February 2023. Genomic DNA was extracted and specific promotor sequence was amplified by polymerase chain reaction (PCR) followed by sequencing then measuring serum concentrations of IL-1β by Enzyme-Linked Immunosorbent Assay (ELISA). The results revealed significant difference in serum levels of IL-1B (P≤0.01), from 1.10-+0.09 in Chronic HCV patients in comparison with its level in healthy controls 7.58± 0.28. Molecular results suggested that single nucleotide polymorphisms in the promoter of IL-1B is probably associated with susceptibility to HCV chronic infection according to this sample of Iraqi patients. In conclusion, the results suggested that variation in serum level and polymorphism in IL-1B is probably associated with susceptibility to hepatitis C virus chronic infection.

Cost stickiness in the Italian Mutual Banks and comparison among Less Significant Banks

This study investigates cost stickiness in the Italian banking system, with a specific focus on Less Significant (LS) banks, including Mutual Banks (MBs), during the period 2006-2019. The research seeks to identify whether LS banks exhibit asymmetric cost behavior, particularly in response to income and credit risk level variations. Utilizing a unique dataset of 5,446 observations and applying econometric models adapted from the seminal work of Anderson et al. (2003), this study provides a novel analysis of cost stickiness within a banking context, an area that has been underexplored in the existing literature. The results reveal significant cost stickiness across all LS banks, with MBs demonstrating more pronounced stickiness than other LS banks. Additionally, the findings show that higher levels of credit risk exacerbate cost stickiness, while greater efficiency mitigates this effect. These insights underscore the importance of tailored cost management strategies in the banking sector, particularly for MBs, and contribute to understanding the unique challenges LS banks face in Italy. The research’s originality lies in its focused examination of cost behavior within a distinct subset of the Italian banking system, providing new perspectives on how smaller, regionally-focused banks manage financial pressures.

Machine Learning for the Sustainable Management of Depth Prediction and Load Optimization in River Convoys: An Amazon Basin Case Study

The seasonal fluctuation of river depths is a critical factor in designing cargo capacity for river convoys and logistics processes used for grain transportation in northern Brazil. Water level variations directly impact the load capacities of pusher convoys navigating the Amazon rivers. This paper presents a machine learning model based on a multilayer perceptron artificial neural network developed with the aim of estimating the cargo capacities of river convoys one year in advance, which is essential for determining load capacities during dry periods. The prediction model was applied to the Tapajós River in the Amazon Basin, Brazil, where grain transportation is significant and relies on inland waterways. Navigability conditions were evaluated in terms of depth and geometric parameters. The results of this case study were satisfactory, validating the computational tool and enabling the assessment of capacity losses during dry periods and the identification of navigation bottlenecks. The main contributions of this work include optimizing river logistics, reducing costs, minimizing environmental impacts, and promoting the sustainable management of water resources in the Amazon. Conclusions drawn from the study indicate that the developed model is highly effective, with an R2 of 0.954 and RMSE of 0.095, demonstrating its potential to significantly enhance river convoy operations and support sustainable development in the region.

Noise and frequency propagation in natural stone processing plants

In this study, 510 noise measurements recorded in eight natural stone processing plants operating in Sivas City, Turkey were evaluated and the noise levels and dominant frequency bands of 11 different processing machines used in these plants were determined. The daily equivalent noise level of all natural stone processing plants was around or above the exposure limit value (87 dBA) specified in relevant regulations. Considering the machines and plant environment, the frequency ranges for the highest noise levels were mostly between 630 Hz - 5000 Hz, centering around 3150 Hz. Variations in the noise level of the processing machines in separate plants where similar processes were carried out was primarily related to the plant size and machine layout, the number of machines operating simultaneously and the type of natural stone processed. While the difference between the noise levels of gangsaws, bridge cutting, ST cutting, head/side cutting, trimming, cement filling, slab polishing, narrow polishing, chamfering and splitting machines were statistically significant, aging machines generated similar noise levels.

Uncovering Interdecadal Pacific Oscillation’s Dominance in Shaping Low-Frequency Sea Level Variability in the South China Sea

The low-frequency sea level variability in the South China Sea (SCS) is examined using high-resolution regional ocean model simulations that span the last six decades. The analysis reveals interdecadal oscillations with a periodicity of 12–13 years as the dominant mode of sea level variability in the SCS. The fluctuations in the Luzon Strait transport (LST) are identified as primary drivers of interannual to interdecadal sea level variability, rather than atmospheric forcing within the SCS. Fourier spectrum analysis is employed to investigate the association between SCS sea level variability and the Interdecadal Pacific Oscillation (IPO), using principal components of SCS sea surface height anomalies, wind stress curl, wind stress components, net short wave flux, as well as the LST and various climate indices. The variations in the SCS sea level are driven by the IPO, which modifies the LST and ocean heat content, impacting the steric sea level.

Impact of the Jenkyns Event on shallow-marine carbonates and coeval emerged paleoenvironments: the Plitvice Lakes region, Croatia

Early Jurassic (late Pliensbachian–early Toarcian) Large Igneous Province (LIP) magmatism affected the entire ocean-atmosphere system culminating in a cascade of paleoenvironmental perturbations known as the Jenkyns Event which globally impacted marine, transitional and terrestrial paleoenvironments. Carbonate platforms at low latitudes in the Western Tethys realm drowned or shifted to non-skeletal production during the early Toarcian due to sea level rise, global warming, and ocean acidification. Unlike deep-marine deposits, shallow-marine carbonates present a challenge in defining global geochemical signals due to common diagenetic modifications. An integrated dataset including δ13Ccarb and δ18Ocarb, TOC, biomicrofacies, SEM, XRD, and palynological study of two stratigraphic successions in the Plitvice Lakes region, Bjelopolje (BJ) and Plitvice Spring (PS), in Croatia, provides an overview of the paleoenvironmental evolution and lateral facies changes in a peritidal setting during the Early Jurassic on the Adriatic Carbonate Platform (AdCP). The investigated stratigraphic succession starts with upper Pliensbachian, peloid-ooid-bioclastic grainstones alternating with fenestral and massive mudstones overlain by lower Toarcian, lagoonal, bioturbated, “spotted” limestones with horizons indicative of short-lived subaerial emergence during the early Toarcian. A negative excursion in δ13Ccarb, foraminifer assemblages, and the predominance of Classopollis pollen within the “spotted” limestones marks the stratigraphic position of the Jenkyns Event. Global-scale events (sea level variation, climate change, C-cycle perturbation, anoxia) operated simultaneously with local to regional synsedimentary tectonics and eustatic movements that preserved the AdCP carbonate factory from collapse or drowning but resulted in pronounced facies differentiation on the shallow-marine carbonate platforms.

Exploring the power of data-driven models for groundwater system conceptualization: a case study of the Grazer Feld Aquifer, Austria

AbstractDeveloping a reliable conceptual model is crucial for analyzing groundwater systems. An essential part of the aquifer conceptualization is the identification of the hydrological stresses that control the hydraulic head fluctuations. By effectively capturing and understanding these stresses, the propagation of potential errors and uncertainties through subsequent modeling steps can be minimized. This study aims to test data-driven models as screening models for conceptualizing a groundwater system. The case study is applied to the Grazer Feld Aquifer in southeast Austria. Time series models are applied to: (1) identify the stresses likely influencing the observed head fluctuations and their spatial variability; (2) identify locations where a lack of understanding of head fluctuations exists; and (3) discuss the limitations and opportunities associated with data-driven models to support system conceptualization. Time series models were created for 144 monitoring wells where sufficient head observations were available during the calibration period (2005–2015). A total of 576 models were developed, incorporating the combinations of stresses: recharge, river level, and a step trend. Following the model selection process, each model was categorized based on its performance and divided into four groups. At 88 sites, recharge and river level variations were identified as the primary controlling stresses influencing head fluctuations. The inclusion of the step trend was found to be necessary at five sites to accurately simulate heads due to dam construction. The application of data-driven models in this study enhanced the identification of key aquifer stresses, facilitating a more informed understanding of the groundwater system.

Influence Mechanism of Water Level Variation on Deformation of Steep and Toppling Bedding Rock Slope

The construction of major hydropower projects globally is challenged by slope deformation in reservoir areas. The deformation and failure mechanisms of large rock slopes are complex and poorly understood, making prevention and management extremely challenging. In order to explore the influence mechanism of the water level variation on the deformation of steep toppling bedding rock slopes, this paper takes the right bank slope near the dam area of the Longtou Hydropower Station as an example, and field investigations, deformation monitoring, physical simulation tests and numerical analyses are carried out. It is found that the slope deformation response is obvious under the influence of the reservoir water level variation, which is mainly reflected in the change in the slope groundwater level, rock mechanical parameters and seepage field in the slope body. The toe of the slope produces plastic deformation and maximum displacement. With the increase in the reservoir water level, the plastic zone expands and the displacement increases, which leads to the intensification of the slope deformation. This paper puts forward that the deformation and failure modes of the steep and toppling bedding rock slope caused by water level variation are due to shear dislocation, bending deformation and toppling fracture. This study reveals the influence mechanism of the water level variation on the deformation of steep and toppling bedding rock slopes, which can provide theoretical support for the construction of major hydropower projects.

Decay time estimate for LEO spacecraft

The growing concerns posed by orbital debris represent a serious threat to the future of space operations in low Earth orbit. With the goal of limiting the formation of new debris, space agencies are proposing international guidelines that satellites should be able to deorbiting within 25 years of the end of their operational life. Orbital decay is typically caused by atmospheric drag, so estimating the decay time of a satellite subject to drag is critical to assessing whether the guidelines are met. However, such estimate is a very challenging task because of the difficulty of accurately modeling atmospheric properties and because of the coupling of orbital dynamics with spacecraft attitude. In this paper, a simplified algorithm based on the King-Hele formulation is proposed to rapidly estimate the decay time of an orbiting satellite without imposing any assumptions on the spacecraft’s nominal size, mass, geometry or attitude. The algorithm accounts for the effect of solar activity level variations on atmospheric properties and drag coefficient through an iterative procedure and can be applied to any object in orbit. Numerical tests show that the predictions in terms of decay times are very accurate for satellites that are quite different in size and geometry, including the presence of an aerodynamic drag augmentation system such as a drag sail.

Arctic and Southern Ocean polar sea level maps and along-tracks from multi-mission satellite altimetry from 2011 to 2021

Polar sea surface height observation by radar altimeters requires missions with high-latitude orbit and specific processing to observe the sea-ice-covered region within fractures in the ice. Here, we combine sea surface height estimates from different radar satellites over the ice-free and ice-covered polar oceans to create cross-calibrated along-tracks and gridded products over the Arctic Ocean (2011–2021) and the Southern Ocean (2013–2021). The sea surface height from our regional polar products is in great agreement with tide gauges and bottom pressure recorders at monthly timescales in seasonally to year-round ice-covered regions. Thanks to the use of several missions and the mapping strategy, our multi-mission products have a greater resolution than mono-mission products. Part of the sea level variability of the Arctic Ocean product is related to the Arctic Oscillation atmospheric circulation. At long term, the Arctic altimetry sea level is coherent with in-situ steric height evolution in the Beaufort gyre, and negative sea level trends over the 10-year period are observed in the East Siberian slope region, which may be related to the local freshwater decrease observed by other studies. Our regional polar sea level products are limited by current understanding of the sea-ice lead measurements, and homogenization of these polar products with global sea level products needs to be tackled.