Satellite Facilities Research Articles

Investigating compressed SAR technique efficiency for land deformation analysis along Hwanggang dam

Abstract Monitoring and determining the land deformation in dam reservoirs is very crucial as it is one of the main factors of dam failure around the world. Hwanggang Dam is located at a strategic location near the inter-Korean border. North Korea frequently released water from the Hwanggang Dam, which often triggers floods and landslides in areas near the inter-Korea border in South Korea. Consistent monitoring of the Hwanggang Dam is very crucial to avoid catastrophic loss of infrastructure and life. This research paper exploits the potential of the Compressed SAR (ComSAR) technique for deformation analysis along Hwanggang Dam. A total of 171 Sentinel-1 images of Hwanggang Dam were downloaded from Alaska Satellite Facility in ascending track acquired between 2016 and 2023 to generate a time-series interferogram stack. The generated interferogram stack was exploited by using the ComSAR technique to estimate deformation along Hwanggang Dam. The resultant estimated deformation shows instability along the Hwanggang Dam embarkment.

Watershed Modelling, Using the Geographical Information System (GIS) Approach (Federal University of Technology Owerri, Imo State Nigeria as Case study)

In a typical watershed area such as the Federal University of Technology, Owerri, Nigeria, watershed modelling is essential for the sustainable management of water resources, protection of ecosystems and more. In this study, we will be creating a watershed model for FUTO, this study will also cover other aspects such as estimating the depression-less flow direction, delineating the flow accumulation, extracting realistic drainage network using the Strahler’s stream order method and we will also delineate the watershed’s boundary and identify possible outlets / pour points, using the digital elevation model (DEM) gotten from Alaska satellite facility used as a main data source in combination with the PC version of ArcGIS software (ArcMap 10.7) and then we extract the hydrologic information from the DEM in ArcGIS using Hydrology tools. The estimation of depression-less flow direction is done by filling the digital elevation model (DEM). This includes performing fill on sinks to ensure proper delineation of basins and streams. If the sinks are not filled, a derived drainage network may be discontinuous. After the DEM has been filled, then we can now move on to delineating the flow accumulation in the study area. The results shows that by using watershed function in ArcGIS for watershed flow direction and accumulation in FUTO can be determined. The results also shows the drainage network that was extracted by Strahler’s method, showing different orders of streams and it also shows the watershed boundary and pour point / outlets along the Otamiri River which the watershed drains into. This work simply shows the applicability of GIS as a tool of watershed delineation and drainage extraction.

A Review- Optimizing Healthcare Delivery: Navigating the Challenges and Benefits of the Satellite Medical Model in Modern Hospital Management

In the rapidly evolving landscape of healthcare management, the Satellite Medical Model has emerged as a strategic solution to enhance service delivery by decentralizing care through a network of satellite facilities connected to a central hub hospital. This model not only improves accessibility and optimizes resource utilization but also addresses workforce shortages, particularly in underserved regions. Rooted in the hub-and-spoke design from the transportation sector, the Satellite Medical Model facilitates efficient healthcare services, allowing primary care units to manage routine cases while more complex conditions are referred to specialized facilities. Despite its advantages, the implementation of this model faces significant challenges, including technical issues related to data security and interoperability, financial constraints, and operational complexities. This paper explores the potential of the Satellite Medical Model in modern hospital management, examining both its benefits and challenges. By identifying strategic approaches to mitigate these barriers, this study aims to provide healthcare leaders with actionable insights to effectively adopt this model, ultimately leading to improved patient outcomes and greater operational efficiency in healthcare delivery.

The “6th R” of sustainability: Repurposing operating room waste for community benefit

BackgroundOperating rooms contribute greatly to hospital waste and greenhouse gas production. Efforts to “green the operating room” have focused on the 5R's of sustainability: reduce, reuse, recycle, rethink, and research. We propose a “6th R” —repurposing— as simple yet effective means of addressing operating room waste. MethodsClean, non-reusable surgical supplies were collected from a satellite facility of a children's hospital during a six-week pilot program. Materials were catalogued and repurposed throughout the community. The potential financial benefits were estimated based upon the value of repurposed goods and savings from reduced waste disposal. ResultsOver 960 items were collected during the 6-week pilot. Materials ranging from plastic trays to surgical towels were donated to organizations throughout the community. Approximate retail value of repurposed items was over $1200. When extrapolated to the entire hospital system, these repurposing efforts could account for over $50,000 in donations and $1300 in operational savings over a calendar year. ConclusionsRepurposing unused surgical items provide environmental, societal, and financial benefits, all while promoting more sustainable healthcare systems.

TOI-1408: Discovery and Photodynamical Modeling of a Small Inner Companion to a Hot Jupiter Revealed by Transit Timing Variations

We report the discovery and characterization of a small planet, TOI-1408 c, on a 2.2 day orbit located interior to a previously known hot Jupiter, TOI-1408 b (P = 4.42 days, M = 1.86 ± 0.02 M Jup, R = 2.4 ± 0.5 R Jup) that exhibits grazing transits. The two planets are near 2:1 period commensurability, resulting in significant transit timing variations (TTVs) for both planets and transit duration variations for the inner planet. The TTV amplitude for TOI-1408 c is 15% of the planet’s orbital period, marking the largest TTV amplitude relative to the orbital period measured to date. Photodynamical modeling of ground-based radial velocity (RV) observations and transit light curves obtained with the Transiting Exoplanet Survey Satellite and ground-based facilities leads to an inner planet radius of 2.22 ± 0.06 R ⊕ and mass of 7.6 ± 0.2 M ⊕ that locates the planet into the sub-Neptune regime. The proximity to the 2:1 period commensurability leads to the libration of the resonant argument of the inner planet. The RV measurements support the existence of a third body with an orbital period of several thousand days. This discovery places the system among the rare systems featuring a hot Jupiter accompanied by an inner low-mass planet.

46th biennial convention of Sigma Gamma Epsilon, University of Tennessee at Martin, September 16-18, 2022

The Society of Sigma Gamma Epsilon (SGE), the national honorary society for the Earth sciences, held its 46th biennial convention (September 16-18, 2022) at satellite facilities of University of Tennessee at Martin (UT Martin) located in Selmer, Tennessee. The convention was hosted by SGE’s Eta Alpha Chapter and the Department of Agriculture, Geoscience, and Natural Resources at UT Martin. Ten (10) of SGE’s approximately 60 active chapters sent delegates to the convention. The traditional convention field trip, an outing to UT Martin’s Coon Creek Science Center, focused on collecting and preparing marine fossils from the Upper Cretaceous Coon Creek Formation. Key accomplishments of the convention include amending the Society’s constitution to reflect changes in membership categories, the adoption of a new mission statement, and broad-ranging discussions related to the revitalization of local chapters following the COVID-19 pandemic. This report provides details about the convention proceedings and provides the various reports presented by national officers, individual chapters, and student committees.

Developing a remote-sensing-based indicator for peat soil vertical displacement. A case study in the Biebrza Valley, Poland

Peatlands play a crucial role in carbon storage, but drainage and climate change-induced hydrological changes drivers degrade peat soils, followed by negative vertical displacement of the soil surface, referred to in the literature as peat subsidence. Assessing peatland subsidence is an important indicator of peatland status that allows the development of peatlands to be revealed over a given period. However, traditional methods are limited in their applicability to large and inaccessible peatlands. In this study, we introduce a remote sensing framework for easily indicating peat subsidence at a large scale. Our framework utilizes the Alaska Satellite Facility (ASF) Interferometry Synthetic Aperture Radar (InSAR) with on-demand cloud computing, employing an optimization process including a Small Baseline Set technique and seasonal-annual search approach. By implementing this approach in the Biebrza Valley, Poland, covering the period from April 2015 to April 2022, we unveiled a tragedy, an annual subsidence rate of 1.44 cm. It means a peat loss between 58.1 and 89.6 million cubic meters over seven years, an annual loss of 86.4 to 132.5 (average 109) m3, approximately 46 tons, of dry matter peat per hectare. This finding was verified through field surveys, with high accuracy. An R2 value of 0.7, and an RMSE value of 0.23 cm determine the reliability of this approach in estimating the vertical displacement. The potential of this tool as a robust method to assess large-scale peatlands would allow for the assessment of average water levels as well as greenhouse gas emissions over large areas of peatlands, even at the continental scale.

Optimizing routing and scheduling of shared autonomous electric taxis considering capacity constrained parking facilities

This paper focuses on routing and scheduling of autonomous electric vehicles to provide reservation-based shared ride services, while a set of parking facilities with limited capacity are used for vehicle intermittent charging. A mixed-integer linear program model is formulated in the form of a vehicle routing problem with satellite facilities (VRPSF), subject to a series of additional time and capacity-related constraints. The objective of the model is to minimize the total operating costs of the system, including those related to vehicle miles traveled and the deployed vehicle fleet size. The number of vehicles inside each parking facility is tracked so as to ensure that the capacity is never exceeded throughout the service horizon. A customized solution method based on an adaptive large neighborhood search algorithm with an explicit treatment of parking facility choices is developed. A series of numerical experiments, consisting of both hypothetical examples and a real-world case study in Hangzhou, China, have been conducted to evaluate the effectiveness and applicability of the proposed model and algorithm. The results demonstrate that ride-sharing services and parking facilities have the potential to significantly reduce the total vehicle energy consumption and operating costs for a shared autonomous electric taxi (SAET) operator in practical scenarios.

#536 Dedicated patient optimization program delivers effective complex intervention improving the lives of vulnerable HD patients

Abstract Background and Aims Hemodialysis (HD) delivery is failing many patients due to a of lack of available evidence/dialysis-based interventions (previously only studied as single interventions in isolation) to improve outcomes; and the industrialization of institutional-based HD imposing a ‘one size fits all’ approach. To respond to the needs of the most vulnerable patients we have instituted a patient optimization program (POP) to support our Renal Program, fully leveraging our research level assessment tools to provide an individualized appreciation of challenges before delivering an equally individualized complex intervention. The aim was to improve subjective experience [symptoms/health related quality of life (HRQoL) measures] and objective evidence of HD related harm. Method Patients who had suboptimal tolerability to HD were identified and referred by the clinical team (after best efforts to address concern as part of standard care). To understand the patients’ individual challenges, a series of physiological, hemodynamic, and HRQoL assessments were completed. Based on these findings, a series of complex foundational (common to all patients treated) and patient specific interventions were applied, and impact rigorously evaluated. HRQoL/symptoms were measured using the dynamic patient reported outcome measurement tool LEVIL [2-4 weeks leading up to the program (baseline) and continually thereafter]. Comprehensive physiological assessment period was two weeks in length (six HD treatments) and included continuous beat to beat hemodynamic monitoring, intradialytic echocardiography (assess myocardial stunning) and objective volume assessment using ultrasound and bioimpedance. The first session was delivered mirroring routine prescription (establish primary response), subsequent treatments were delivered implementing a variety of foundational, patient/disease specific interventions in a staged manner. Results To date 13 patients have completed the program, referred for a variety of reasons [refractory hypotension (5/13), intradialytic hypotension (2/13) and poor HRQoL [symptoms—cramping, headache, pruritus, insomnia (8/13)]. Complexes of challenges were present in 9/13. All patients had multiple components of dialysis altered. POP was associated with a marked improvement in a range of subjective and objective outcomes. Subjectively, HRQoL improved by 10% [composite LEVIL scores 69.5 ± 15.5 at baseline, 76.5 ± 17 after POP participation (p 0.03)], energy by 18% (64.7 ± 16.2, 76.5 ± 6.4, p 0.01), general wellbeing by 11% (76.5 ± 6.6, 85.2 ± 4.2, p 0.02), and post-dialysis recovery improved from 13.3 ± 16.1 hours to only 2 ± 1.9 hours (p 0.02). Objectively, intradialytic weight gain decreased by 36% (2333.3 ± 1151.8 ml at baseline to 1483.3 ± 591.3 ml, p 0.03), systolic blood pressure improved by 12% [94.9 ± 28.5 mmHg at baseline to 106.2 ± 30 mmHg post optimization p < 0.0001 (despite midodrine being discontinued in 8/13 patients previously dependent on it)]. Tolerability of HD improved (cardiac output 6.4 ± 0.1, 6.5 ± 1, p 0.002 and intradialytic systemic vascular resistance response 15 ± 23.6% at baseline to 48.7 ± 53%, p < 0.0001). Improvement in hemodynamic tolerability led to a reduction in HD induced myocardial stunning larger than reported with any previously applied single intervention; regional wall motion abnormality fell from 5.6 ± 2.4 at baseline (severe stunning) to only 1.2 ± 1.3 (p 0.02) over the two-week program. 2/13 patients who had previously been declined transplantation were accepted and need to repatriate from satellite facilities to in-centre was avoided. Conclusion For the first time, we have created an opportunity for the most challenging patients who have failed conventional best efforts. We have successfully demonstrated the impact of delivering a complex intervention (with a degree of treatment personalization) targeting physiological failure in the most vulnerable HD patients. POP improved HRQoL (principal impact measure), hemodynamic stability and treatment tolerability. Having demonstrated the effectiveness of this approach, we now focus on solutions to up-scale this success.

Impact of Severe Winter Weather on Operations of a Radiation Oncology Department

IntroductionDuring winter of 2022, Western New York faced two major storms with blizzard conditions and record-breaking snowfall. The severe weather resulted in power outages, and travel bans. This study investigates the impact of these conditions on patient adherence to radiotherapy. Combining data from a large academic center and its satellite clinic, this single-center study is shedding light on the challenges faced by cancer care facilities during severe weather and proposing suggestions to prevent and mitigate harm done by severe weather. MethodsIn this study, data was collected using the MOSAIQ Record and Verify system (v. 2.81) to generate deidentified reports of scheduled and treated patients. The treatment adherence rate was calculated by dividing the number of patients treated by the total number of patients scheduled. Data was specifically collected for patients undergoing treatment on linear accelerators at a primary academic center and a satellite facility. The study focused on working days from November 1, 2022, to March 31, 2023, excluding weekends and holidays (as treatments are not routinely scheduled). Severe weather days were identified using advisories from the National Weather Service and local institution, including specific periods in November, December, and January. ResultsIn the study, 15,010 scheduled treatment visits were recorded across the academic center and the satellite clinic. The mean daily treatment adherence rate was 91.7%. Severe weather conditions led to a significant reduction in adherence, with rates dropping to 77.8%. Adherence rates during non-severe weather days were notably higher at 93.9%. Statistical analysis confirmed the substantial impact of severe weather on adherence (p<0.001). Severe weather had a more pronounced impact on the satellite clinic during periods of severe weather with absolute reduction in adherence rates of 21.9% vs. 15% in primary hospital). Moreover, adherence rates at the satellite clinic vs. primary hospital site was lower even under standard operating conditions (92.2% vs 94.0%, p<0.001). ConclusionAs a part of operational planning, it is important to be aware how severe weather can impact treatment adherence. The study findings underscore the importance of proactive measures to ensure patient access to healthcare services during adverse weather events and highlight the broader significance of incorporating Social Determinants of Health (SDOH) considerations into contingency planning for maintaining treatment continuity.

Optimizing Healthcare Delivery: Navigating the Challenges and Benefits of the Satellite Medical Model in Modern Hospital Management

In the rapidly evolving landscape of healthcare management, the Satellite Medical Model has emerged as a strategic solution to enhance service delivery by decentralizing care through a network of satellite facilities connected to a central hub hospital. This model not only improves accessibility and optimizes resource utilization but also addresses workforce shortages, particularly in underserved regions. Rooted in the hub-and-spoke design from the transportation sector, the Satellite Medical Model facilitates efficient healthcare services, allowing primary care units to manage routine cases while more complex conditions are referred to specialized facilities. Despite its advantages, the implementation of this model faces significant challenges, including technical issues related to data security and interoperability, financial constraints, and operational complexities. This paper explores the potential of the Satellite Medical Model in modern hospital management, examining both its benefits and challenges. By identifying strategic approaches to mitigate these barriers, this study aims to provide healthcare leaders with actionable insights to effectively adopt this model, ultimately leading to improved patient outcomes and greater operational efficiency in healthcare delivery.

Evaluating SAR Radiometric Terrain Correction Products: Analysis-Ready Data for Users

Operational applications for Synthetic Aperture Radar (SAR) are under development around the world, driven by the free-and-open access of SAR C-band observations that Sentinel-1 of Copernicus has provided since 2014. Radiometric Terrain Correction (RTC) data are key entry-level products for multiple applications ranging from ecosystem to hazard monitoring. Various open-source software packages exist to create RTC products from Single Look Complex (SLC) or Ground Range Detected (GRD) level SAR data, including the Interferometric SAR Computing Environment (ISCE), and the Sentinel-1 Toolbox from the European Space Agency (SNAP 8). Despite the growing availability of RTC software solutions, little work has been performed to identify differences between RTC products generated using different software packages. This work evaluates several Sentinel-1 RTC products and two other Sentinel-1 Analysis Ready Data (ARD) to address the following questions: (1) Which software provides the most accurate RTC product? and (2) how appropriate for analysis are other non-RTC products that are readily available? The RTCs are produced with GAMMA, ISCE-2, and SNAP 8. The other two ARD products evaluated consisted of an angular-based radiometric slope correction produced in Google Earth Engine (GEE) following Vollrath et al., and the Sentinel-1 GRD product. Products are evaluated across 10 sites in a single image approach for (1) radiometric calibration, (2) geometric corrections, and for (3) geolocation quality. In addition, time-series stacks over two sites representing varied terrain and ecosystems are evaluated. The GAMMA-derived RTC product implemented by the Alaska Satellite Facility (ASF) is used as a reference for some of the time-series metrics. The results provide direct guidance and recommendations about the quality of the RTC and ARD products obtained from open source methods. The results indicate that it is not recommended to use the GRD product with no radiometric or geometric corrections for any applications given low performance in multiple metrics. The radiometric calibration and geometric corrections have overall good performance for all open-source solutions, only the non-RTC products (Vollrath et al. and GRD) portray some significant variances in steep terrain. The geolocation assessment indicated that the GRD product has the most significant displacement errors, followed by SNAP 8 with Digital Elevation Model (DEM) matching, and ISCE-2. RTCs created without DEM-matching performed better for both GAMMA and SNAP 8. The time-series results indicate that SNAP 8 products align more closely to GAMMA products than other open-source software in terms of radiometric and geometric quality. This understanding of software performance for SAR image processing is key to designing the affordable and scalable solutions needed for the operational application of SAR Sentinel-1 data.

Centralization and Organization Reproduction: Ethnic Innovation in R&amp;D Centers and Satellite Locations

We study the relationship between firm centralization and organizational reproduction in satellite locations. For decentralized firms, the ethnic compositions of inventors in satellite locations mostly resemble their host cities with little link to the inventor composition of their parent firms’ research and development headquarters. For highly centralized firms, by contrast, organizational reproduction has an explanatory power equal to half or more of the host city effect. Reproduction is strongest when a firm exhibits a hands-on approach to the satellite facility, such as cross-facility team collaboration or internal talent mobility. Funding: W. R. Kerr thanks the National Science Foundation, Harvard Business School, the Smith Richardson Foundation, and the Ewing Marion Kauffman Foundation for financial support that made this research possible. Supplemental Material: The online appendix is available at https://doi.org/10.1287/orsc.2021.16070 .

Multi-attribute two-echelon location routing: Formulation and dynamic discretization discovery approach

We study the two-echelon location-routing system under tight synchronization constraints, in addition to several other interacting attributes. Prompted, in particular, by city-logistics applications, the system we address concerns a two-echelon distribution layout composed of a set of platform facilities and a set of intermediate satellite facilities to deliver freight from supply zones outside the city to customers within. The problem setting includes time-dependent multicommodity demand, time windows, lack of storage capacity at intermediate facilities, and synchronization at these facilities of the fleets operating on different echelons. The problem requires the selection of facilities at both levels, the allocation of suppliers to platforms and of customers to satellites, and the routing and scheduling of vehicles at each echelon, in order to deliver the freight from platforms to customers, through the satellites. The lack of storage capacity of the shared facilities, the satellites, requires tight scheduling of the vehicle routes and demand itineraries, i.e., departure times from the platforms and satellites, and the synchronization of vehicle routes at satellites for efficient transshipment operations. We introduce the problem setting, present a mixed-integer programming formulation, and a dynamic discretization discovery-based exact solution method for the problem. We perform thorough analyses to assess the impact of the problem attributes and requirements on the system behaviour and algorithm performance.

Climatic and topographic controls on glacial changes (1973-2020) in Shigar Basin, Central Karakoram, Northern Pakistan.

The Hindukush, Karakorum, and Himalaya (HKH) mountains are often referred to as the "Third Pole" because of high snow, being a major freshwater resource and early indicator of climate change. Therefore, research on the dynamics of glacier changes and their relationship with climate and topographic variability is essential for sustainable water resource management and adaptation strategies in Pakistan. In this contribution, we delineated 187 glaciers and examined these glacier changes in the Shigar Basin from 1973 to 2020 using Corona, Landsat Operational Land Imager/Enhanced Thematic Mapper Plus/Thematic Mapper/Multispectral Scanner System (OLI/ETM/TM/MSS), Alaska Satellite Facility (ASF), and Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) imageries. The total glacier area decreased from 2796.31 ± 132 km2 in 1973 to 2756.27 ± 63 km2 in 2020 at an average rate of - 0.83 ± 0.03 km2yr-1. Specifically, during the period of 1990-2000, these glaciers shrank most heavily at an average rate of - 2.372 ± 0.08 km2yr-1. In contrast, an increased rate of 0.57 ± 0.02 km2yr-1 in total glacier area was observed during the recent decade (2010-2020). Moreover, the glaciers with gentle slopes retreated less heavily than the steep ones. There was reduction in glacier coverage and length for all slope classes, and a small reduction was observed with gentle slopes, while higher losses were observed on steep slope gradients. The transition of glaciers in the Shigar Basin may be attributed by the direct influence of glacier size and topographical characteristics. By comparing with climate records, our findings suggest that the overall reduction in glacier area from 1973 to 2020 was associated with declining precipitation (- 0.78 mmm/year) and rising temperature (0.045°C/year) trends in the region, and glacier advances in recent decade (2010-2020) were likely to be driven by increased winter and autumn precipitation.

Multifaceted Quality Improvement Interventions to Prevent Hemodialysis Catheter–Related Bloodstream Infections: A Systematic Review

Central venous catheters (CVCs) are widely used for hemodialysis but are prone to burdensome and costly bloodstream infections. We determined whether multifaceted quality improvement interventions in hemodialysis units can prevent hemodialysis catheter-related bloodstream infections (HDCRBSI). Systematic review. PubMed, EMBASE, and CENTRAL were searched from inception to April 23, 2022, to identify randomized trials, time-series analyses, and before-after studies that examined the effect of multifaceted quality improvement interventions on the incidence of HDCRBSI or access-related bloodstream infections (ARBSI) among people receiving hemodialysis outside of the intensive care unit (ICU). Two people independently extracted data and assessed the risk of bias and quality of evidence using validated tools. Intervention effects, validity, and characteristics of studies with the same design were compared. Differences between study designs were described. We included 21 studies from 8,824 identified by our search. Among 15 studies that measured HDCRBSI, 2 methodologically heterogenous cluster randomized trials reported discordant intervention effects, 2 interrupted time-series analyses reported favorable interventions with discordant patterns of effect, and 11 before-after studies reported favorable interventions with a very high risk of bias. Among 6 studies that only measured ARBSI, 1 time-series analysis and 1 before-after study did not find a favorable intervention effect, and 4 before-after studies reported a favorable effect with a very high risk of bias. The overall quality of evidence was low for HDCRBSI and very low for ARBSI. Nine definitions of HDCRBSI were used. Ten studies included hospital-based and satellite facilities but did not report separate intervention effects for each type of facility. Multifaceted quality improvement interventions may prevent HDCRBSI outside the ICU. However, evidence supporting them is of low quality, and further carefully conducted studies are warranted. Registered at PROSPERO with registration number CRD42021252290. People with kidney failure rely on central venous catheters to facilitate life-sustaining hemodialysis treatments. Unfortunately, hemodialysis catheters are a common source of problematic bloodstream infections. Quality improvement programs have effectively prevented catheter-related infections in intensive care units, but it is unclear whether they can be adapted to patients using hemodialysis catheters in the community. In a systematic review that included 21 studies, we found that most quality improvement programs were reported to be successful. However, the findings were mixed among higher-quality studies, and overall the quality of evidence was low. Ongoing quality improvement programs should be complemented by more high-quality research.

Tribute to Ernie Gould

Tribute to Ernie Gould

Rapid Mapping of Slow-Moving Landslides Using an Automated SAR Processing Platform (HyP3) and Stacking-InSAR Method

The increasing number of landslide hazards worldwide has placed greater demands on the production and updating of landslide inventory maps. As an important data source for landslide detection, interferometric synthetic aperture radar (InSAR) data processing is time-consuming and also requires specialized knowledge, which severely hinders its widespread application. At present, a new cloud-based online platform, i.e., Alaska Satellite Facility’s Hybrid Pluggable Processing Pipeline (ASF HyP3) was developed for massive SAR data processing. In this study, combining the HyP3 online platform and Stacking-InSAR method, we constructed a new easy-to-use processing chain for rapidly identifying slow-moving landslides over large areas. With this processing chain, a total of 923 interferometric pairs covering an area of over 1800 km2 were processed within a few hours (about 4 to 5 h). A total of 81 slow-moving landslides were immediately detected and mapped using Stacking-InSAR method, of which 65 landslides were confirmed by previous studies and 16 landslides were newly detected. Results show that the new processing chain can greatly improve the efficiency of wide-area landslide mapping and is expected to serve as an effective tool for rapid updating the existing landslide inventories and contribute to the prevention and management of geological hazards.

Coproduction and modeling spatial contact networks prevent bias about infectious hematopoietic necrosis virus transmission for Snake River Basin salmonids

Much remains unknown about variation in pathogen transmission across the geographic range of a free-ranging fish or animal species and about the influence of movement (associated with husbandry practices or animal behavior) on pathogen transmission. Salmonid hatcheries are an ideal system in which to study these processes. Salmonid hatcheries are managed for endangered species recovery, supplementation of threatened or at-risk fish stocks, support of fisheries, and ecosystem stability. Infectious hematopoietic necrosis virus (IHNV) is a rhabdovirus of significant concern to salmon aquaculture. Landscape IHNV transmission dynamics previously had been estimated only for salmonid hatcheries in the Lower Columbia River Basin (LCRB). The objectives of this study were to estimate IHNV transmission dynamics in a unique geographic region, the Snake River Basin (SRB), and to quantitatively estimate the effect of model coproduction on inference because previous assessments of coproduction have been qualitative. In contrast to the LCRB, the SRB has hatchery complexes consisting of a main hatchery and ≥1 satellite facility. Knowledge about hatchery complexes was held by a subset of project researchers but would not have been available to project modelers without coproduction. Project modelers generated and tested multiple versions of Bayesian susceptible-exposedinfected models to realistically represent the SRB and estimate the effect of coproduction. Models estimated the frequency of transmission routes, route-specific infection probabilities, and infection probabilities for combinations of salmonid hosts and IHNV lineages. Model results indicated that in the SRB, avoiding exposure to IHNV-positive adult salmonids is the most important action to prevent juvenile infections. Migrating adult salmonids exposed juvenile cohort-sites most frequently, and the infection probability was greatest following exposure to migrating adults. Without coproduction, the frequency of exposure by migrating adults would have been overestimated by 70 cohort-sites, and the infection probability following exposure to migrating adults would have been underestimated by∼0.09. The coproduced model had less uncertainty in the infection probability if no transmission route could be identified (Bayesian credible interval (BCI) width = 0.12) compared to the model without coproduction (BCI width = 0.34). Evidence for virus lineage MD specialization on steelhead and rainbow trout (both Oncorhynchus mykiss) was apparent without model coproduction. In the SRB, we found a greater probability of virus lineage UC infection in Chinook salmon (Oncorhynchus tshawytscha) compared to in O. mykiss, whereas in the LCRB, UC more clearly exhibited a generalist approach. Coproduction influenced estimates that depended on transmission routes, which operated differently at main hatcheries and satellite sites within hatchery complexes. Hatchery complexes are found outside of the SRB and are not specific to salmonid hatcheries alone. There is great potential for coproduction and modeling spatial contact networks to advance understanding about infectious disease transmission in complex production systems and surrounding free-ranging animal populations.

CHALLENGES OF INSAR DEM DERIVATION WITH SENTINEL-1 SAR IN DENSELY VEGETATED HUMID TROPICAL ENVIRONMENT

Abstract. Since the launch of the Sentinel-1 Synthetic Aperture Radar (SAR) in 2014 by the European Space Agency (ESA), there has been renewed interest in SAR data for various application, including DEM derivation with SAR Interferometry (InSAR) technique. However, the success of the InSAR technique in deriving DEM with Sentinel-1 SAR which has been largely acknowledged in sparsely vegetated regions, remains controversial in the densely vegetated environment due to certain challenges, which have rarely been reported. The aim of this study is to highlight some of the obstacles of InSAR DEM derivation with Sentinel-1 SAR over densely vegetated humid tropical environment. Suitable Sentinel-1 image pairs over part of Johor, Peninsular Malaysia, determined in terms of perpendicular and temporal baselines using the Alaska Satellite Facility (ASF) online baseline computation tool, were downloaded from the ASF archive and processed accordingly using the Sentinel Application Platform (SNAP). Difficulty in acquiring suitable image pairs, phase decorrelation and poor coherence, and unwrapping problems are some of the encountered challenges of InSAR DEM derivation with Sentinel-1 SAR in the densely vegetated humid tropics reported in this study. This study shall provide to the geoscientific community insights on InSAR DEM derivation with Sentinel-1 SAR in densely vegetated environments and initiate discussion on the technique’s promise in such environments.