EUREC⁴A observations from the SAFIRE ATR42 aircraft

As part of the EUREC4A (Elucidating the role of cloud-circulation coupling in climate) field campaign, which took place in January and February 2020 over the western tropical Atlantic near Barbados, the French SAFIRE ATR42 research aircraft conducted 19 flights in the lower troposphere. Each flight followed a common flight pattern that sampled the atmosphere around the cloud-base level, at different heights of the subcloud layer, near the sea surface and in the lower free troposphere. The aircraft's payload included a backscatter lidar and a Doppler cloud radar that were both horizontally oriented, a Doppler cloud radar looking upward, microphysical probes, a cavity ring-down spectrometer for water isotopes, a multiwavelength radiometer, a visible camera and multiple meteorological sensors, including fast rate sensors for turbulence measurements. With this instrumentation, the ATR characterized the macrophysical and microphysical properties of trade-wind clouds together with their thermodynamical, turbulent and radiative environment. This paper presents the airborne operations, the flight segmentation, the instrumentation, the data processing and the EUREC4A datasets produced from the ATR measurements. It shows that the ATR measurements of humidity, wind and cloud-base cloud fraction measured with different techniques and samplings are internally consistent, that meteorological measurements are consistent with estimates from dropsondes launched from an overflying aircraft (HALO), and that water isotopic measurements are well correlated with data from the Barbados Cloud Observatory. This consistency demonstrates the robustness of the ATR measurements of humidity, wind, cloud-base cloud fraction and water isotopic composition during EUREC4A. It also confirms that through their repeated flight patterns, the ATR and HALO measurements provided a statistically consistent sampling of trade-wind clouds and of their environment. The ATR datasets are freely available at the locations specified in Table 11.

Mammal fauna of Chisinau airport, Republic of Moldova

Introduction. Airport territories are large, containing a high variety of biotopes, mostly open type, and are relatively protected against intense human activity, thus creating favorable conditions for many mammal species that serve as trophic source for many bird species. Material and methods. The studies were performed during 2012-2014 on the territory of Chisinau airport and within the adjacent ecosystems. The mammals were recorded by direct observations, based on traces and trophic activity on routes ranging from 1 to 3 km. The small mammals were assessed with traps. The bat species were identified according to their flight pattern and using the ultrasound detector. Results. In the airport, 31 species of mammals were registered: 5 insectivore species, 7 bat species, 14 rodent species, 1 hare species and 4 carnivorous species. The most widespread, common and abundant were the rodents and the fox. Among small rodent species, the most abundant was Apodemus sylvaticus with 51.6%, followed by the Microtus arvalis (38.9%), while on the airport grassland, the field vole dominated with more than 60%. The diet of Athene noctua included predominantly Mus musculus with over 51%, followed by M. arvalis with 23.7%. 7 species are rare and 5 protected – bicolor shrew and 4 bat species. Conclusions. The airport territory and adjacent ecosystems provide favorable conditions for many mammal species. The presence of rodents favors the occurrence of rather high number of prey birds, which represent a threat for the safety of aircraft flights. The fox can pose direct threat to flight safety.

USE OF EXPERT SOFTWARE AND PHEROMONES TRAPS FOR BIOCENOTIC STRESS MONITORING AND EARLY WARNING OF TREATMENTS AGAINST INSECTS IN ORCHARDS

This paper presents our results in use of the specialized software and specific modules for microclimate monitoring and pest biological cycle assessment, to evaluate and quantify the attack risk for microclimate monitoring, combined with 6 type specific pheromones produced in Romania, in order to determine their efficacy in detecting the targeted micro Lepidoptera, assess their population flight pattern, as well and the biocenotic stress, both tools categories aiming to the precise positioning of the treatments to achieve integrated pests management and reduce the overall impact of the treatments with insecticides on the environment. According the fruit species, several strategies have been defined and followed by several insecticide applications into the bearing orchards, to achieve a better control of damaging micro Lepidoptera. Use of the mixed monitoring systems in tandem with specific pheromones contributed to a more efficient use of the insecticides and increased performances, both for pome and stone fruit species as well.

A Review: Recent Progress in the Design and Development of Nonlinear Radars

This paper presents an extensive review of nonlinear response-based radar systems. Nonlinear radars are generally used for clutter suppression purposes. These radars detect the nonlinear response generated by diodes and transistors are used as a tag for target localization. Utilizing the nonlinearity properties of these devices, these radars have been used for purposes including locating humans trapped in earthquakes and avalanches, identifying migratory patterns of animals, examining the flight pattern of bees, and detecting bugs in electronic devices. This paper covers the utilization of these radars in human vital signs monitoring, detecting targets in a clutter-rich environment, etc. State-of-the-art nonlinear radars’ high-level architectures, design challenges, and limitations are discussed here. Recent works and results obtained by the authors are also summarized.

Multi UAV Coverage Path Planning in Urban Environments

Coverage path planning (CPP) is a field of study which objective is to find a path that covers every point of a certain area of interest. Recently, the use of Unmanned Aerial Vehicles (UAVs) has become more proficient in various applications such as surveillance, terrain coverage, mapping, natural disaster tracking, transport, and others. The aim of this paper is to design efficient coverage path planning collision-avoidance capable algorithms for single or multi UAV systems in cluttered urban environments. Two algorithms are developed and explored: one of them plans paths to cover a target zone delimited by a given perimeter with predefined coverage height and bandwidth, using a boustrophedon flight pattern, while the other proposed algorithm follows a set of predefined viewpoints , calculating a smooth path that ensures that the UAVs pass over the objectives. Both algorithms have been developed for a scalable number of UAVs, which fly in a triangular deformable leader-follower formation with the leader at its front. In the case of an even number of UAVs, there is no leader at the front of the formation and a virtual leader is used to plan the paths of the followers. The presented algorithms also have collision avoidance capabilities, powered by the Fast Marching Square algorithm. These algorithms are tested in various simulated urban and cluttered environments, and they prove capable of providing safe and smooth paths for the UAV formation in urban environments.

Behavioural measurements of hearing-sensitivity in swarming Anopheles coluzzii mosquitoes reveal an unprecedentedly low threshold

BackgroundMale and female mosquitoes of many species mate in swarms consisting of males and uninseminated females; males form station-keeping swarms and mating chases ensue as soon as a male detects the flight tones of a female. The auditory organs of mosquitoes have been reported to be the most sensitive among arthropods, enabling them to track their flying mate by the sound of the female’s flight tones during mating chases. Previous studies on hearing thresholds have mainly used electrophysiological methods, which unfortunately limit the natural behaviour of the mosquitoes. This study explores male auditory behavioural sensitivity to female flight tones.MethodsWe developed a behavioural method for measuring hearing sensitivity in swarming male mosquitoes. Free-flying male Anopheles coluzzii mosquitoes were released in a large arena (∼2 m high × 2 m × 1 m) with a visually conspicuous object on the ground that stimulates swarming behaviour consisting of elliptical flight pattern over the object. Males were exposed to a range of natural and synthetic played-back sounds of female flight emanating from a speaker located at the same height as the swarm centre and 0.9 m away from it. We monitored the responses of males to female sound by recording the flight-tone and flight-dynamic responses of males. Calibrated sound-levels were measured at the swarm centre; the changing distances between the speaker and the flying males as well as other measurement uncertainties were taken into account to estimate the sound levels that males were effectively exposed to.ResultsWe show that the mean male behavioural threshold of particle-velocity hearing lies between 13-20 dB SVL (95%-CI). A conservative estimate of 20 dB SVL (i.e., less than a particle velocity of 0.5 µm/s) is already 12 to 26 dB less than most of the published electrophysiological measurements on Johnston’s organ sensilla. Our results confirm, under laboratory conditions, the high behavioural hearing-sensitivity of swarming mosquitoes recently found with swarming Aedes communis in the field, and suggest a hearing threshold at least two times lower than that of published results (26 dB SVL or 1 µm/s particle-velocity). In addition, we established that 1) the first harmonic of Anopheles coluzzii female flight sound is sufficient for males to detect her presence, 2) males respond with a greater amplitude to single-female sounds than to group-female sounds and 3) males respond to the playback of single-female sound as much as to pure-sound at a constant frequency and amplitude.

Spiral SAR Imaging with Fast Factorized Back-Projection: A Phase Error Analysis

This paper presents a fast factorized back-projection (FFBP) algorithm that can satisfactorily process real P-band synthetic aperture radar (SAR) data collected from a spiral flight pattern performed by a drone-borne SAR system. Choosing the best setup when processing SAR data with an FFBP algorithm is not so straightforward, so predicting how this choice will affect the quality of the output image is valuable information. This paper provides a statistical phase error analysis to validate the hypothesis that the phase error standard deviation can be predicted by geometric parameters specified at the start of processing. In particular, for a phase error standard deviation of ~12°, the FFBP is up to 21 times faster than the direct back-projection algorithm for 3D images and up to 13 times faster for 2D images.

Comprehensive quantification of height dependence of entrainment mixing between stratiform cloud top and environment

Different entrainment-mixing processes of turbulence are crucial to processes related to clouds; however, only a few qualitative studies have been concentrated on the vertical distributions of entrainment-mixing mechanisms with low vertical resolutions. To quantitatively study vertical profiles of entrainment-mixing mechanisms with a high resolution, the stratiform clouds observed in the Physics of Stratocumulus Top (POST) project are examined. The unique sawtooth flight pattern allows for an examination of the vertical distributions of entrainment-mixing mechanisms with a 5 m vertical resolution. Relative standard deviation of volume mean radius divided by relative standard deviation of liquid water content is introduced to be a new estimation of microphysical homogeneous mixing degree, to overcome difficulties of determining the adiabatic microphysical properties required in existing measures. The vertical profile of this new measure indicates that entrainment-mixing mechanisms become more homogeneous with decreasing altitudes and are consistent with the dynamical measures of Damköhler number and transition scale number. Further analysis shows that the vertical variation of entrainment-mixing mechanisms with decreasing altitudes is due to the increases of turbulent dissipation rate in cloud and relative humidity in droplet-free air and the decrease of size of droplet-free air. The results offer insights into the theoretical understanding and parameterizations of vertical variation of entrainment-mixing mechanisms.

Approaching wildlife with drones: using scientific literature to identify factors to consider for minimising disturbance

ABSTRACT Drones are a modern alternative to manned aircraft for aerial surveys, however approaching wildlife with drones may still cause disturbance. Understanding the factors influencing animal responses to drone flights is fundamental for informing guidance on lowest-impact flight practices. We reviewed scientific literature on drone flights conducted to approach wildlife and collated and quantified references to factors that should be considered in the development of guidelines and policies. The most referenced controllable factors were approach distance, noise emissions and airspeed. Other frequently referenced controllable factors included drone type, take-off distance, flight pattern, pilot experience and competence, whether consecutive flights were conducted and flight duration. The most referenced environmental factors were animal taxa, biological state of animals and ambient noise, followed by whether conspecifics are present, weather variables, habitat variables, whether animals have received previous exposure to anthropogenic settings, animals’ behaviour prior to drone flights and whether predators are present. Policies and protocols that address these factors have an increased probability of minimising disturbance of drone flights. The variability in animal responses across different taxa, different ways drone flights are performed and the different circumstances they are deployed in highlights the need for taxa-specific protocols that also account for geographical and biological variations.