| 1. |
- Brydegaard, Mikkel, et al.
(författare)
-
Lidar reveals activity anomaly of malaria vectors during pan-African eclipse
- 2020
-
Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 6:20
-
Tidskriftsartikel (refereegranskat)abstract
- Yearly, a quarter billion people are infected and a half a million killed by the mosquito-borne disease malaria. Lack of real-time observational tools for continuously assessing the unperturbed mosquito flight activity in situ limits progress toward improved vector control. We deployed a high-resolution entomological lidar to monitor a half-kilometer static transect adjacent to a Tanzanian village. We evaluated one-third million insect observations during five nights, four days, and one annular solar eclipse. We demonstrate in situ lidar classification of several insect families and their sexes based on their modulation signatures. We were able to compare the fine-scale spatiotemporal activity patterns of malaria vectors during ordinary days and an eclipse to disentangle phototactic activity patterns from the circadian mechanism. We observed an increased insect activity during the eclipse attributable to mosquitoes. These unprecedented findings demonstrate how lidar-based monitoring of distinct mosquito activities could advance our understanding of vector ecology.
|
|
| 2. |
- Brydegaard, Mikkel, et al.
(författare)
-
Short-Wave infrared atmospheric scheimpflug lidar
- 2018
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. ; 176
-
Konferensbidrag (refereegranskat)abstract
- Atmospheric dual-band Scheimpflug lidar is demonstrated at 980 and 1550 nm. Signals are compared during three weather conditions, and the spatio-temporal resolution of the atmospheric structure is considered. The potential for aerosol classification is evaluated, and future directions are discussed.
|
|
| 3. |
- Brydegaard, Mikkel, et al.
(författare)
-
The Scheimpflug lidar method
- 2017
-
Ingår i: Lidar Remote Sensing for Environmental Monitoring 2017. - : SPIE. - 9781510612693 ; 10406
-
Konferensbidrag (refereegranskat)abstract
- The recent several years we developed the Scheimpflug lidar method. We combined an invention from the 19th century with modern optoelectronics such as diode lasers and CMOS array from the 21st century. The approach exceeds expectations of background suppression, sensitivity and resolution beyond known from time-of-flight lidars. We accomplished multiband elastic atmospheric lidars for resolving single particles and aerosol plumes from 405 nm to 1550 nm. We pursued hyperspectral differential absorption lidar for molecular species. We demonstrated a simple method of inelastic hyperspectral lidar for profiling aquatic environments and vegetation structure. Not least, we have developed polarimetric Scheimpflug lidar with multi-kHz sampling rates for remote modulation spectroscopy and classification of aerofauna. All these advances are thanks to the Scheimpflug principle. Here we give a review of how far we have come and shed light on the limitations and opportunities for future directions. In particular, we show how the biosphere can be resolved with unsurpassed resolution in space and time, and share our expectation on how this can revolutionize ecological analysis and management in relation to agricultural pests, disease vectors and pollinator problematics.
|
|
| 4. |
- Hjort, Marcus, et al.
(författare)
-
Increased Inflammatory Activity in Patients 3 Months after Myocardial Infarction with Nonobstructive Coronary Arteries
- 2019
-
Ingår i: Clinical Chemistry. - : AMER ASSOC CLINICAL CHEMISTRY. - 0009-9147 .- 1530-8561. ; 65:8, s. 1023-1030
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Around 5%-10% of patients with myocardial infarction (MI) present with nonobstructive coronary arteries (MINOCA). We aimed to assess pathophysiological mechanisms in MINOCA by extensively evaluating cardiovascular biomarkers in the stable phase after an event, comparing MINOCA patients with cardiovascular healthy controls and MI patients with obstructive coronary artery disease (MI-CAD).METHODS: Ninety-one biomarkers were measured with a proximity extension assay 3 months after MI in 97 MINOCA patients, 97 age-and sex-matched MI-CAD patients, and 98 controls. Lasso analyses (penalized logistic regression models) and adjusted multiple linear regression models were used for statistical analyses.RESULTS: In the Lasso analysis (MINOCA vs MI-CAD), 8 biomarkers provided discriminatory value: P-selectin glycoprotein ligand 1, C-X-C motif chemokine 1, TNF-related activation-induced cytokine, and pappalysin-1 (PAPPA) with increasing probabilities of MINOCA, and tissue-type plasminogen activator, B-type natriuretic peptide, myeloperoxidase, and interleukin-1 receptor antagonist protein with increasing probabilities of MI-CAD. Comparing MINOCA vs controls, 7 biomarkers provided discriminatory value: N-terminal pro-B-type natriuretic peptide, renin, NF-kappa-B essential modulator, PAPPA, interleukin-6, and soluble urokinase plasminogen activator surface receptor with increasing probabilities of MINOCA, and agouti-related protein with increasing probabilities of controls. Adjusted multiple linear regression analyses showed that group affiliation was associated with the concentrations of 7 of the 8 biomarkers in the comparison MINOCA vs MI-CAD and 5 of the 7 biomarkers in MINOCA vs controls.CONCLUSIONS: Three months after the MI, the biomarker concentrations indicated greater inflammatory activity in MINOCA patients than in both MI-CAD patients and healthy controls, and a varying degree of myocardial dysfunction among the 3 cohorts.
|
|
| 5. |
- Jansson, Samuel, et al.
(författare)
-
A Scheimpflug lidar used to observe insect swarming at a wind turbine
- 2020
-
Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X. ; 117
-
Tidskriftsartikel (refereegranskat)abstract
- Wind turbines have considerable impact on flying animals, particularly bats, which are sometimes killed in large numbers by the moving rotors. A longstanding question remains why bats are attracted to wind turbines and risk their lives among the moving rotor blades. One hypothesis is that they feed on insects swarming around the turbine towers and another is that they congregate there to court. The two are not mutually exclusive and may occur more or less simultaneously. It has been difficult to distinguish these hypothesis, because techniques that permit observations of small insects over the relevant distances (~100 m) in the dark are lacking. In this study, we monitored insects at the top of a wind turbine using a novel high-resolution Scheimpflug lidar. The instrument was employed around dusk during ten late summer nights in 2018, with the principal aim to evaluate its performance under real field conditions. Insect swarms were observed near the top of the turbine tower on every night. They appeared in short intervals and varied in density, timing, exact location and size of the swarming insects from day to day. Swarms formed in the afternoon and either dispersed around sunset before the emergence of bats, or remained until darkness, when bats arrived at the turbine. Some of the bats fed there, as indicated by ultrasonic feeding-buzzes, and also engaged in social interactions possibly including courtship, as indicated by song-flights. Daily variation in the formation, dispersal and behavior of the insect swarms appeared to be influenced by temperature and wind speed and also differed among the insect species.
|
|
| 6. |
- Jansson, Samuel, et al.
(författare)
-
Real-time dispersal of malaria vectors in rural Africa monitored with lidar
- 2021
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16:3 March
-
Tidskriftsartikel (refereegranskat)abstract
- Lack of tools for detailed, real-time observation of mosquito behavior with high spatio-temporal resolution limits progress towards improved malaria vector control. We deployed a high-resolution entomological lidar to monitor a half-kilometer static transect positioned over rice fields outside a Tanzanian village. A quarter of a million in situ insect observations were classified, and several insect taxa were identified based on their modulation signatures. We observed distinct range distributions of male and female mosquitoes in relation to the village periphery, and spatio-temporal behavioral features, such as swarming. Furthermore, we observed that the spatial distributions of males and females change independently of each other during the day, and were able to estimate the daily dispersal of mosquitoes towards and away from the village. The findings of this study demonstrate how lidar-based monitoring could dramatically improve our understanding of malaria vector ecology and control options.
|
|
| 7. |
- Jansson, Samuel, et al.
(författare)
-
Spatial monitoring of flying insects over a Swedish lake using a continuous-wave lidar system
- 2023
-
Ingår i: Royal Society Open Science. - 2054-5703. ; 10:5
-
Tidskriftsartikel (refereegranskat)abstract
- We have used a continuous-wave bi-static lidar system based on the Scheimpflug principle in measurements on flying insects above, and in the vicinity of, a small lake located in a forested area in Southern Sweden. The system, which operates on triangulation principles, has a high spatial resolution at close distance, followed by a subsequent decline in resolution further from the sensor, related to the compact system design with a separation of transmitter and receiver by only 0.81 m. Our study showed a strong increase in insect abundance especially at dusk, but also at dawn. Insect numbers decreased over water compared to over land, and larger insects were over-represented over water. Further, the average size of the insects increased at night compared to day time.
|
|
| 8. |
- Malmqvist, Elin, et al.
(författare)
-
Applications of KHZ-CW Lidar in Ecological Entomology
- 2016
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X. ; 119
-
Tidskriftsartikel (refereegranskat)abstract
- The benefits of kHz lidar in ecological entomology are explained. Results from kHz-measurements on insects, carried out with a CW-lidar system, employing the Scheimpflug principle to obtain range resolution, are presented. A method to extract insect events and analyze the large amount of lidar data is also described.
|
|
| 9. |
- Malmqvist, Elin, et al.
(författare)
-
CW Laser radar for combustion diagnostics
- 2018
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 176
-
Tidskriftsartikel (refereegranskat)abstract
- A CW-laser radar system developed for combustion diagnostics is described. The system is based on triangulation to attain range information. A portable system has been constructed and here we show some result from measurements in various flames, for example Rayleigh scattering thermometry and monitoring of particle distributions with high temporal and spatial resolution. The concept can equally well be based on pulsed lasers, allowing suppression of background emission through gated detection.
|
|
| 10. |
- Malmqvist, Elin, et al.
(författare)
-
Effective parameterization of laser radar observations of atmospheric fauna
- 2016
-
Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - 1077-260X. ; 22:3
-
Tidskriftsartikel (refereegranskat)abstract
- The pace at which the world's ecosystems and biodiversity of, e.g., pollinators decline is currently at a rate where it is challenging to document. In recent years, our group has made an effort to bridge the disciplines of laser remote sensing and biophotonics, and we have developed lidar methods for inventorying the biosphere. Here, we present an effective method for extracting fauna observations from atmospheric lidar data and reducing the observations to a set of descriptive parameters. Kilohertz-lidar data are used, the essential steps are walked through and a glimpse of the obtainable data product is presented.
|
|
| 11. |
- Malmqvist, Elin
(författare)
-
From Fauna to Flames : Remote Sensing with Scheimpflug Lidar
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents applications of the Scheimpflug Lidar (S-Lidar) method. The technique has been applied to combustion diagnostics on a scale of several meters as well as fauna detection and monitoring over distances of kilometers. Lidar or laser radar is a remote sensing technique where backscattering of laser light is detected with range resolution along the direction of the laser beam. It is an established method in e.g. atmospheric sensing where it is used to map and monitor gases and aerosols. In contrast to conventional Lidar, which uses a time-of-flight approach, Scheimpflug Lidar uses imaging to achieve range resolution. The laser beam transmitted from the Lidar system is sharply imaged onto a detector, resulting in range resolution along the sensor. This is done by placing the laser beam, the collection optics and the detector according to two trigonometrical conditions called the Scheimpflug and hinge rules. This kind of Lidar technique enables the use of small, continuous-wave diode lasers and line-array detectors with kHz sampling rates. A general description of the equations governing the achievable measurement range and resolution of S-Lidar are presented. The way the equations relate to the conventional Lidar equation is also discussed as well as the impact of the beam width. The instrumentation and experimental considerations for far range S-Lidar for aerial fauna monitoring are described and some temporally and spatially resolved data from field campaigns in Africa, China and Sweden are presented. A method used to reduce and analyze the large amount of collected data is also described. For the short-range applications, down-scaled versions of the system were developed. These systems are described as well as their applications. The short range system has mostly been used to investigate the potential of the technique to be applied for combustion diagnostics, and results from measurements in flames using both elastic and inelastic optical techniques, such as Rayleigh scattering and two-line atomic fluorescence are presented. A hyperspectral Lidar system aimed at aquatic applications is also presented.
|
|
| 12. |
- Malmqvist, Elin, et al.
(författare)
-
Scheimpflug Lidar for combustion diagnostics
- 2018
-
Ingår i: Optics Express. - 1094-4087. ; 26:12, s. 14842-14858
-
Tidskriftsartikel (refereegranskat)abstract
- A portable Lidar system developed for large-scale (~1-20 m) combustion diagnostics is described and demonstrated. The system is able to perform remote backscattering measurements with range and temporal resolution. The range resolution is obtained by sharply imaging a part of the laser beam onto a CMOS-array or ICCD detector. The large focal depth required to do this is attained by placing the laser beam, the collection optics and the detector in a so-called Scheimpflug configuration. Results from simulations of the range capabilities and range resolution of the system are presented and its temporal resolution is also discussed. Various applications, important for combustion diagnostics, are also demonstrated, including Rayleigh scattering thermometry, aerosol detection and laser-induced fluorescence measurements. These measurements have been carried out using various continuous-wave GaN diode lasers, emitting in the violet-blue (405 – 450 nm) wavelength regime. It is anticipated that Scheimpflug Lidar will provide a useful and versatile diagnostic tool for combustion research, not only for fundamental studies, but in particular for applications at industrial sites.
|
|
| 13. |
- Malmqvist, Elin, et al.
(författare)
-
The bat–bird–bug battle : Daily flight activity of insects and their predators over a rice field revealed by high-resolution scheimpflug lidar
- 2018
-
Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 5:4
-
Tidskriftsartikel (refereegranskat)abstract
- We present the results of, to our knowledge, the first Lidar study applied to continuous and simultaneous monitoring of aerial insects, bats and birds. It illustrates how common patterns of flight activity, e.g. insect swarming around twilight, depend on predation risk and other constraints acting on the faunal components. Flight activity was monitored over a rice field in China during one week in July 2016, using a high-resolution Scheimpflug Lidar system. The monitored Lidar transect was about 520 m long and covered approximately 2.5 m3. The observed biomass spectrum was bimodal, and targets were separated into insects and vertebrates in a categorization supported by visual observations. Peak flight activity occurred at dusk and dawn, with a 37 min time difference between the bat and insect peaks. Hence, bats started to feed in declining insect activity after dusk and stopped before the rise in activity before dawn. A similar time difference between insects and birds may have occurred, but it was not obvious, perhaps because birds were relatively scarce. Our observations are consistent with the hypothesis that flight activity of bats is constrained by predation in bright light, and that crepuscular insects exploit this constraint by swarming near to sunset/sunrise to minimize predation from bats.
|
|
| 14. |
- Malmqvist, Elin, et al.
(författare)
-
Two-dimensional OH-thermometry in reacting flows using photofragmentation laser-induced florescence
- 2016
-
Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 169, s. 297-306
-
Tidskriftsartikel (refereegranskat)abstract
- In the present work, the possibility of using photofragmentation laser-induced fluorescence (PFLIF) for thermometry in different reacting flows is investigated. Hydroxyl (OH) fragments are created by UV-laser (266nm) fragmentation of hydrogen peroxides (H2O2 and HO2), whereupon the fluorescence, induced while scanning the wavelength of a second laser across the A2σ+(v = 1)-X2Π(v = 0) absorption band (around 282nm) of the generated OH fragments, is collected and detected. The temperature is determined by fitting simulated OH-excitation spectra of different temperatures to the experimentally recorded spectrum. In combustion, hydrogen peroxides are intermediate species formed during the low-temperature oxidation of the fuel, and hence they are present in a region covering a wide temperature span, ranging from unburnt to burnt gas temperatures. Thus, LIF of OH photofragments stemming from hydrogen peroxides allows for thermometry covering a wider temperature range than LIF of naturally present OH radicals. There is another important advantage of the concept in that the temperature sensitivity of OH excitation spectra is greater at lower temperatures. The method is demonstrated for two-dimensional (2-D) thermometry in three different measurement situations, namely a free flow of vaporized H2O2 at room temperature, a preheated mixture of CH4/N2/O2/O3 at intermediate temperatures (300-600K), where the OH fragments stem from photodissociation of O3 followed by chemical reactions, and in an optical homogeneous charge compression ignition (HCCI) engine prior to ignition, i.e. at elevated pressures and temperatures. It is found that the technique performs well in all three cases, with measured temperatures in good agreement with thermocouple readings, for the two first cases, and with temperatures calculated based on the ideal gas law using measured pressure traces as input for the engine measurements. The quantitative 2-D temperature images acquired in the engine experiments reveal inhomogeneous temperature distributions, clearly illustrating the capacity of the technique to yield crucial experimental input to engine modelers and designers. The accuracy of the technique in the temperature range 300-600K is lower than 23K. For the room temperature case the precision is 4.3%, corresponding to 12K.
|
|
| 15. |
- Malmqvist, Tove, et al.
(författare)
-
Byggnadens klimatpåverkan kan minska med en genomtänkt projekteringsprocess
- 2018
-
Rapport (populärvet., debatt m.m.)abstract
- Idag står byggprocessen av nybyggda hus för lika mycket eller rentav större klimatpåverkan än byggnaders drift under 50 år. Trots det är det ytterst få byggprojekt som arbetar med att minimera byggprocessens energianvändning och klimatpåverkan från hela livscykeln. Det finns inte heller några krav i Boverkets byggregler som styr mot låg klimatpåverkan från byggandet. Men det finns en rad olika möjligheter till förbättring, inte minst för arkitekter.
|
|
| 16. |
- Moberg, Christina, et al.
(författare)
-
De unga gör helt rätt när de stämmer staten
- 2022
-
Ingår i: Aftonbladet. - 1103-9000.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
|
|
| 17. |
- Salvén, Håkan, et al.
(författare)
-
”Gymnasieelever bör studera filosofi”
- 2023
-
Ingår i: Svenska dagbladet. - 1101-2412. ; :2023-04-16
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Filosofin har en särställning när det handlar om att stärka elevernas skydd mot desinformation och att utveckla deras kritiska tänkande. Därför bör ämnet vara obligatoriskt för elever på de teoretiska programmen i Gymnasiet.
|
|
| 18. |
- Song, Ziwei, et al.
(författare)
-
Application of lidar remote sensing of insects in agricultural entomology on the Chinese scene
- 2020
-
Ingår i: Journal of Applied Entomology. - : Wiley. - 0931-2048 .- 1439-0418. ; 144:3, s. 161-169
-
Tidskriftsartikel (refereegranskat)abstract
- Insect pest management is a very important aspect for plant protection in crops production. Remote sensing provides a large number of techniques that are beneficial in entomological research. Although entomological radars have been used for studying migrations of insects for many years, most of entomological radar studies have been vertically tracing high-altitude migration behaviour of insects. Light detection and ranging (lidar) is a counterpart to radar, now operating in the optical part of the electromagnetic spectrum, which has been recently applied for monitoring of insects at low altitude. Such techniques, in particular low-cost continuous-wave (CW) bi-static systems based on the Scheimpflug arrangement, have been rapidly developing during the last decade. As a result, optical methods present new and fascinating possibilities. Based on experience from a 2-week field campaign in rice paddy fields, we here present an overview of lidar remote sensing applied to the Chinese scene. The capability of a CW Scheimpflug lidar system in monitoring the insects was studied. We present results on insect abundance in relation to time of the day and weather conditions. We also identified insect species by analysing wing-beat frequencies and studied their attraction to ultraviolet (UV) lamp located close to the horizontal laser sampling path during night time. Results showed that the insect species were abundant, that insects detected by the lidar system were attracted to light and that light rain increased the insect activity. The lidar detection system had a high read-out frequency, enabling the estimation of insect wing-beat frequencies.
|
|
| 19. |
- Svenungsson, Elisabet, et al.
(författare)
-
Antiphospholipid antibodies in patients with myocardial infarction with and without obstructive coronary arteries
- 2022
-
Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 291:3, s. 327-337
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Recent studies demonstrate that prothrombotic antiphospholipid antibodies (aPL) are overrepresented in patients with myocardial infarction (MI) due to coronary artery disease (MICAD). However, it is not known whether aPL differ between the two subsets of MI: MICAD and MI with nonobstructive coronary arteries (MINOCA). Objectives: To determine whether aPL are associated with MINOCA or MICAD, or with hypercoagulability as assessed by activated protein C–protein C inhibitor (APC–PCI) complex. Methods: Well-characterized patients with MINOCA (n = 98), age- and gender-matched patients with MICAD (n = 99), and healthy controls (n = 100) were included in a cross-sectional case–control study. Autoantibodies (IgA/G/M) targeting cardiolipin and β2glycoprotein-I and specific nuclear antigens were analyzed by multiplexed bead technology. The concentration of APC–PCI was determined as a measure of hypercoagulability by an immunofluorometric sandwich assay. Results: Both prevalence and titers of aPL of the IgG isotype (anti-cardiolipin and/or anti-β2glycoprotein-I) were higher in patients with MINOCA and MICAD than in controls. aPL IgG positivity was twice as frequent among patients with MICAD than MINOCA (11% vs. 6%, nonsignificant). We observed no group differences regarding aPL IgA/M or antibodies targeting specific nuclear antigens. Levels of APC–PCI were elevated in aPL IgG-positive compared to aPL IgG-negative MICAD patients. Conclusions: aPL IgG, but not IgA/M, are enriched particularly in patients with MICAD but also in patients with MINOCA, as compared to controls. Interestingly, signs of hypercoagulability—measured by increased levels of the APC–PCI complex—were present in aPL IgG-positive MICAD patients, indicating an association with functional disturbances of the coagulation system.
|
|
| 20. |
- Zhao, Guangyu, et al.
(författare)
-
Inelastic hyperspectral lidar for aquatic ecosystems monitoring and landscape plant scanning test
- 2018
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 176
-
Tidskriftsartikel (refereegranskat)abstract
- We have developed an aquatic inelastic hyperspectral lidar with unrestricted focal-depth and enough sensitivity and spatio-temporal resolution to detect and resolve position and behavior of individual sub-millimeter aquatic organisms. We demonstrate ranging with monitoring of elastic echoes, water Raman signals and fluorescence from chlorophyllbearing phytoplankton and dye tagged organisms. The system is based on a blue CW diode laser and a Scheimpflug optical arrangement.
|
|
| 21. |
- Zhao, Guangyu, et al.
(författare)
-
Inelastic hyperspectral lidar for profiling aquatic ecosystems
- 2016
-
Ingår i: Laser and Photonics Reviews. - : Wiley. - 1863-8880. ; 10:5, s. 807-813
-
Tidskriftsartikel (refereegranskat)abstract
- Monitoring the aquatic environment and the life of free-floating organisms remains on the borderline of our technical capabilities. Therefore, our insights into aquatic habitats, such as, abundance and behavior of organisms are limited. In order to improve our understanding of aquatic life, we have developed a low-cost inelastic hyperspectral lidar with unlimited focal depth and enough sensitivity and spatiotemporal resolution to detect and resolve position and behavior of individual submillimeter organisms. In this work, we demonstrate elastic as well as molecular ranging by using the water Raman band, and by observing fluorescence from chlorophyll and from dye-tagged organisms. We present an aquatic laser-diode-based inelastic light detection and ranging (lidar) system with unprecedented sensitivity, spatiotemporal resolution and number of spectral bands. Our system offers new opportunities for quantitative in situ studies of aquatic organisms, and has the potential to considerably advance our understanding of biological life in aquatic systems. (Figure presented.).
|
|
| 22. |
- Zhao, Guangyu, et al.
(författare)
-
Particle profiling and classification by a dual-band continuous-wave lidar system
- 2018
-
Ingår i: Applied Optics. - 1559-128X. ; 57:35, s. 10164-10171
-
Tidskriftsartikel (refereegranskat)abstract
- A dual-band continuous-wave (CW) light detection and ranging (lidar) system has been developed for particle classification. In this lidar system, the range-resolved atmospheric backscattering signal is recorded by an optical imaging system satisfying the Scheimpflug principle instead of the conventional time-of-flight approach. It is thus possible to employ low-cost and compact CW diode lasers, facilitating the development of a robust multiple-wavelength atmospheric lidar system that can attain high accuracy of the retrieved parameters of atmospheric particles. The present work demonstrates a dual-band Scheimpflug lidar system employing two diode lasers at 405 nm (0.5 W) and 808 nm (3.2 W). Exposures are milliseconds apart and interpolated. Measurements of various types of particles and smoke have been performed to verify the feasibility of using the present system for improved particle classification and sizing, for the situation when plumes were dilute and no significant opacity was detected.
|
|
| 23. |
- Zhu, Shiming, et al.
(författare)
-
Insect abundance over Chinese rice fields in relation to environmental parameters, studied with a polarization-sensitive CW near-IR lidar system
- 2017
-
Ingår i: Applied Physics B: Lasers and Optics. - : Springer Science and Business Media LLC. - 0946-2171. ; 123:7
-
Tidskriftsartikel (refereegranskat)abstract
- Effective monitoring of flying insects is of major societal importance in view of the role of insects as indispensable pollinators, destructive disease vectors and economically devastating agricultural pests. The present paper reports on monitoring of flying agricultural pests using a continuous-wave lidar system in a rice-field location in Southern China. Using a Scheimpflug arrangement, range resolution over several 100 m long observational paths was achieved. The system operates with two perpendicularly polarized near-infrared lasers, which are activated intermittently, and back-scattered radiation from insects was recorded by a linear array detector placed after a linear polarizer. Our polarization sensitive system was used to monitor the flying insect diurnal activity and also the influence of changes in weather conditions, e.g., the occurrence of rain. Activity strongly peaked at dusk and rose again, although to a lower extent, just before dawn. At the onset of rainfall, a strong increase in insect counts occurred which was interpreted as the rain-induced bringing down of high-altitude migrant insects.
|
|
| 24. |
- Zhu, Shiming, et al.
(författare)
-
Insect remote sensing using a polarization sensitive cw lidar system in Chinese rice fields
- 2018
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 176
-
Tidskriftsartikel (refereegranskat)abstract
- A joint Chinese-Swedish field campaign of Scheimpflug continuous-wave lidar monitoring of rice-field flying pest insects was pursued in very hot July weather conditions close to Guangzhou, China. The occurrence of insects, birds and bats with almost 200 hours of round-the-clock polarization-sensitive recordings was studied. Wing-beat frequency recordings and depolarization properties were used for target classification. Influence of weather conditions on the flying fauna was also investigated.
|
|
