Compressed SAR Interferometry in the Big Data Era

Modern Synthetic Aperture Radar (SAR) missions provide an unprecedented massive interferometric SAR (InSAR) time series. The processing of the Big InSAR Data is challenging for long-term monitoring. Indeed, as most deformation phenomena develop slowly, a strategy of a processing scheme can be worked on reduced volume data sets. This paper introduces a novel ComSAR algorithm based on a compression technique for reducing computational efforts while maintaining the performance robustly. The algorithm divides the massive data into many mini-stacks and then compresses them. The compressed estimator is close to the theoretical Cramer–Rao lower bound under a realistic C-band Sentinel-1 decorrelation scenario. Both persistent and distributed scatterers (PSDS) are exploited in the ComSAR algorithm. The ComSAR performance is validated via simulation and application to Sentinel-1 data to map land subsidence of the salt mine Vauvert area, France. The proposed ComSAR yields consistently better performance when compared with the state-of-the-art PSDS technique. We make our PSDS and ComSAR algorithms as an open-source TomoSAR package. To make it more practical, we exploit other open-source projects so that people can apply our PSDS and ComSAR methods for an end-to-end processing chain. To our knowledge, TomoSAR is the first public domain tool available to jointly handle PS and DS targets.

Bird community monitoring at New River Gorge National River, Gauley River National Recreation Area, and Bluestone National Scenic River, 1997 - 2018

Birds are prominent features of National Park Service lands and are effective indicators for monitoring ecosystem health. Assessing the temporal change of avian species abundance depends on long-term monitoring of bird communities and trends, however long-term monitoring programs are generally uncommon. In this report, we summarize 22 years (1997-2018) of point count data across five sites on West Virginia National Park Service lands (three in New River Gorge National River, one in Gauley River National Recreation Area, and one in Bluestone National Scenic River) and compare these results to our analysis of Breeding Bird Survey data for the same time period across all of West Virginia. The objectives of this analysis are two-fold: 1) describe the biotic integrity of the National Park Service lands in West Virginia and 2) Quantify trends in guilds and species abundance. During the 20-year period of this survey, 85 breeding resident species were detected. The West Virginia National Park Service lands are home to stable populations of Wood Thrush and Yellow-billed Cuckoo, both species of continental concern by Partners in Flight. Seven species have declined precipitously on NPS lands during this time period. Three of these species are also experiencing declines across the rest of West Virginia (Blue-gray Gnatcatcher, Carolina Chickadee, Kentucky Warbler), but the other 4 species are stable across West Virginia (Acadian Flycatcher, Black-throated Green Warbler, Northern Parula, Swainson’s Warbler). Four species that are declining across West Virginia (Great Crested Flycatcher, Indigo Bunting, Red-eyed Vireo, and Worm-eating Warbler) are stable on southern West Virginia NPS lands. Additionally, the upper-canopy foraging guild of species has decreased significantly on NPS lands in southern West Virginia. An analysis of community biotic integrity revealed that the southern West Virginia NPS lands have been stable at a rating of high biotic integrity every year for the duration of this survey. Future research should delve into the underlying factors that may be driving the trends in abundance at different scales.

Evaluation of nocturnal vs. morning measures of heart rate indices in young athletes

Purpose The purpose of this study was to compare heart rate (HR) and heart rate variability in young endurance athletes during nocturnal sleep and in the morning; and to assess whether changes in these values are associated with changes in submaximal running (SRT) and counter-movement jump (CMJ) performance. Methods During a three-week period of similar training, eleven athletes (16 ± 1 years) determined daily HR and heart rate variability (RMSSD) during sleep utilizing a ballistocardiographic device (Emfit QS), as well as in the morning with a HR monitor (Polar V800). Aerobic fitness and power production were assessed employing SRT and CMJ test. Results Comparison of the average values for week 1 and week 3 revealed no significant differences with respect to nocturnal RMSSD (6.8%, P = 0.344), morning RMSSD (13.4%, P = 0.151), morning HR (-3.9 bpm, P = 0.063), SRT HR (-0.7 bpm, P = 0.447), SRT blood lactate (4.9%, P = 0.781), CMJ (-4.2%, P = 0.122) or training volume (16%, P = 0.499). There was a strong correlation between morning and nocturnal HRs during week 1 (r = 0.800, P = 0.003) and week 3 (r = 0.815, P = 0.002), as well as between morning and nocturnal RMSSD values (for week 1, r = 0.895, P<0.001 and week 3, r = 0.878, P = 0.001). Conclusion This study concluded that HR and RMSSD obtained during nocturnal sleep and in the morning did not differ significantly. In addition, weekly changes in training and performance were small indicating that fitness was similar throughout the 3-week period of observation. Consequently, daily measurement of HR indices during nocturnal sleep provide a potential tool for long-term monitoring of young endurance athletes.

Long-Term Monitoring of Different Field Traffic Management Practices in Cereals Production with Support of Satellite Images and Yield Data in Context of Climate Change

Cereals in Europe are mainly grown with intensive management. This often leads to the deterioration of the physical properties of the soil, especially increasing bulk density due to heavy machinery traffic, which causes excessive soil compaction. Controlled traffic farming (CTF) technology has the potential to address these issues, as it should be advantageous technology for growing cereals during climate change. The aim of this study was to compare the yield potential of CTF and standardly used random traffic farming (RTF) technology using yield maps obtained from combine harvester and satellite imagery as a remote sensing method. The experiment was performed on a 16-hectare experimental field with a CTF system established in 2009 (with conversion from a conventional (ploughing) to conservation tillage system). Yield was compared in years when small cereals were grown, a total of 7 years within a 13-year period (2009–2021). The results show that CTF technology was advantageous in dry years. Cereals grown in the years 2016, 2017 and 2019 had significantly higher yields under CTF technology. On the contrary, in years with higher precipitation, RTF technology had slightly better results—up to 4%. This confirms higher productivity when using CTF technology in times of climate change.

Perspectives on biotic responses to repeated wildfires from decades of long-term empirical studies

ABSTRACT Fire can have marked impacts on biodiversity and on ecosystem condition. However, it is the sequence of multiple fires over a prolonged period of time which can have the most marked effects on biodiversity and on ecosystem condition. A good understanding of these effects comes from long-term studies. In this article we outline some of the key perspectives on the effects of fire on ecosystems and biodiversity from two large-scale, long-term monitoring studies in south-eastern Australia. These are studies in the montane ash forests of the Central Highlands of Victoria and at Booderee National Park in the Jervis Bay Territory. These studies have shown that the effects of fires are strongly influenced by: (1) The condition of an ecosystem before a fire (e.g. the age of a forest at the time it is burnt). (2) Conditions after the fire such as the extent of herbivory in regenerating vegetation and whether the ecosystem is subject to post-fire (salvage) logging. (3) Fire history (e.g. the number of past fires and the time since the previous fire). And, (4) Interactions between fire and other ecosystem drivers such as logging. We discuss some of the key implications for conservation and resource management that arise from these studies including the need to: (a) Reduce the number of stressors in some ecosystems to facilitate post-fire recovery. (b) Recognize that pre-fire human disturbances can elevate fire severity in some forest ecosystems, with corresponding negative effects on elements of the biota, and, (c) Acknowledge the inherent patchiness of wildfires and the value of unburnt areas and places burnt at low severity as critical refugia for some species; it is critical that these locations are managed accordingly (e.g. by limited additional disturbances within them). Finally, many of the insights discussed in this article have emerged only through long-term studies. More long-term monitoring and research is needed to truly understand and better manage fire in Australian ecosystems.