Miniature high-frequency chilled-mirror hygrometer for atmospheric measurements aboard fixed wing UAS

A small light-weight in-house made miniature chilled-mirror hygrometer (CMH) for fixed wing UAS (unmanned aircraft system) is presented, with its features and limitations. Therefore, first measurements of the CMH equipped on the small research UAS of type MASC‑3 (multi-purpose airborne sensor carrier) operated by the University of Tübingen are shown. A comparison against a very accurate state of the art capacitive industrial humidity sensor (SHT31) is done. The sensor consists of a TEC (thermoelectric cooler) covered by a gold mirror. The TEC is controlled by a commercially available microprocessor with an on-board PID (proportional-integral-derivative) controller. The results of the CMH measurements are in good agreement with the industrial-made capacitive sensor. The absolute accuracy of the measured dew point temperature by the CMH is in the range of ±0.2 K. Spectra show evidence that the CMH is capable to measure turbulent humidity fluctuations in the atmosphere with a temporal resolution of up to 10 Hz. Such a fast humidity sensor aboard a small UAS has the potential to study humidity fluxes in the surface layer over complex terrain, behind wind energy converters and humidity variations over land and sea surfaces in general

Air temperature measurements using autonomous self-recording dataloggers in mountainous and snow covered areas

High mountain areas are poorly represented by official weather observatories. It implies that new instruments must be evaluated over snow-covered and strongly insolated environments (i.e. mid-latitude mountain areas). We analyzed uncertainty sources over snow covered areas including: 1) temperature logger accuracy and bias of two widely used temperature sensors (Tinytag and iButton); 2) radiation shield performance under various radiation, snow, and wind conditions; 3) appropriate measurement height over snow covered ground; and 4) differences in air temperature measured among nearby devices over a horizontal band. The major results showed the following. 1) Tinytag performance device (mean absolute error: MAE≈ 0.1–0.2°C in relation to the reference thermistor) was superior to the iButton (MAE≈ 0.7°C), which was subject to operating errors. 2) Multi-plate radiation shield showed the best performance under all conditions (> 90% samples has bias between ±0.5°C). The tube shield required wind (> 2.5ms⁠−1) for adequate performance, while the funnel shield required limited radiation (< 400Wm⁠−2). Snow cover causes certain overheating. 3) Air temperatures were found to stabilize at 75–100cm above the snow surface. Air temperature profile was more constant at night, showing a considerable cooling on near surface at midday. 4) Horizontal air temperature differences were larger at midday (0.5°C). These findings indicate that to minimize errors air temperature measurements over snow surfaces should be carried out using multi-plate radiation shields with high-end thermistors such as Tinytags, and be made at a minimum height above the snow covered ground.This study was funded by the research projects “El papel de la nieve en la hidrología de la peninsula ibérica y su respuesta a procesos de cambio global-HIDROIBERNIEVE-CGL2017-82216-R” and CLIMPY “Characterization of the evolution of climate and provision of information for adaptation in the Pyrenees” (FEDER-POCTEFA)

Evaluation of ARM Tethered Balloon System instrumentation for supercooled liquid water and distributed temperature sensing in mixed-phase Arctic clouds

A tethered balloon system (TBS) has been developed and is being operated by Sandia National Laboratories (SNL) on behalf of the U.S. Department of Energy’s (DOE) Atmospheric Radiation Measurement (ARM) User Facility in order to collect in situ atmospheric measurements within mixed-phase Arctic clouds. Periodic tethered balloon flights have been conducted since 2015 within restricted airspace at ARM’s Advanced Mobile Facility 3 (AMF3) in Oliktok Point, Alaska, as part of the AALCO (Aerial Assessment of Liquid in Clouds at Oliktok), ERASMUS (Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems), and POPEYE (Profiling at Oliktok Point to Enhance YOPP Experiments) field campaigns. The tethered balloon system uses helium-filled 34 m3 helikites and 79 and 104 m3 aerostats to suspend instrumentation that is used to measure aerosol particle size distributions, temperature, horizontal wind, pressure, relative humidity, turbulence, and cloud particle properties and to calibrate ground-based remote sensing instruments. Supercooled liquid water content (SLWC) sondes using the vibrating wire principle, developed by Anasphere Inc., were operated at Oliktok Point at multiple altitudes on the TBS within mixed-phase clouds for over 200 hours Sonde-collected SLWC data were compared with liquid water content derived from a microwave radiometer, Ka-band ARM Zenith radar, and ceilometer at the AMF3, as well as liquid water content derived from AMF3 radiosonde flights. The in situ data collected by the Anasphere sensors were also compared with data collected simultaneously by an alternative SLWC sensor developed at the University of Reading, UK; both vibrating wire instruments were typically observed to shed their ice quickly upon exiting the cloud or reaching maximum ice loading. Tethered balloon fiber optic distributed temperature sensing measurements were also compared with AMF3 radiosonde temperature measurements. Combined, the results indicate that TBS distributed temperature sensing and supercooled liquid water measurements are in reasonably good agreement with remote-sensing and radiosonde-based measurements of both properties. From these measurements and sensor evaluations, tethered balloon flights are shown to offer an effective method of collecting data to inform and constrain numerical models, calibrate and validate remote sensing instruments, and characterize the flight environment of unmanned aircraft, circumventing the difficulties of in-cloud unmanned aircraft flights such as limited flight time and in-flight icing

A study to define meteorological uses and performance requirements for the Synchronous Earth Observatory Satellite

The potential meteorological uses of the Synchronous Earth Observatory Satellite (SEOS) were studied for detecting and predicting hazards to life, property, or the quality of the environment. Mesoscale meteorological phenonmena, and the observations requirements for SEOS are discussed along with the sensor parameters

Ultra-light airborne measurement system for investigation of urban boundary layer dynamics

Winter smog episodes are a severe problem in many cities around the world. The following two mechanisms are responsible for influencing the level of pollutant concentrations: emission of pollutants from different sources and associated processes leading to formation of secondary aerosols in the atmosphere and meteorology, including advection, which is stimulated by horizontal wind, and convection, which depends on vertical air mass movements associated with boundary layer stability that are determined by vertical temperature and humidity gradients. The aim of the present study was to evaluate the performance of an unmanned aerial vehicle (UAV)-based measurement system developed for investigation of urban boundary layer dynamics. The evaluation was done by comparing the results of temperature, relative humidity, wind speed and particulate matter fraction with aerodynamic diameter below 10 m ($PM_{10}$) concentration vertical profiles obtained using this system with two reference meteorological stations: Jagiellonian University Campus (JUC) and radio transmission tower (RTCN), located in the urban area of Krakow city, Southern Poland. The secondary aim of the study was to optimize data processing algorithms improving the response time of UAV sensor measurements during the ascent and descent parts of the flight mission

Society Dilemma of Computer Technology Management in Today\u27s World

Abstract - Is it true that some of the inhabitants of the world’s today are still hesitant in using computers? Research has shown that today many people are still against the use of computers. Computer technology management can be said to be obliterated by security problems. Research shows that some people in society feel reluctant or afraid to use computers because of errors and exposure of their privacy and their sophistication, which sometimes are caused by computer hackers and malfunction of the computers. The dilemma of not utilizing computer technology at all or, to its utmost, by certain people in the universe has absolutely posed a problem to the innovation of computers. This problem results in finding each time ways to simplify computers development and production and what they are meant to be used for. Every year new computers are being developed which makes the previous ones obsolete. They are developed to entice those who have not been utilizing them and to encourage those already using them by simplifying the features of the computers and improving their software and services. The doubt instilled in the mind of those not utilizing computer technology and those not using them to its utmost result in a flood of computers. Research shows that the computer technology market and its use are at their peak because developers and manufacturers think that the more improvements are made, the more there would be new users or customers. Therefore, they are developing and producing more computers. And this may create a flood

Innovative Strategies for Observations in the Arctic Atmospheric Boundary Layer

In this thesis, consisting of five scientific papers, I investigate the potential of unmanned aircraft systems (UAS) in stable boundary layer (SBL) research, by developing and applying a new innovative observation strategy. In this strategy we supplement ground-based micrometeorological observations from masts and remote-sensing systems with a number of different UAS. To achieve good agreement between the different systems employed in this approach, I further investigate the quality and intercomparability of UAS-based observations of atmospheric temperature, humidity, pressure and wind, and develop and apply common, best-practice data processing methods. In Paper I we give a brief introduction to the ISOBAR project and provide an overview over the first SBL campaign at Hailuoto and the prevailing synoptic, sea-ice and micrometeorological conditions. We demonstrate the quality of our measurement approach by combining UAS profile data with observations from the wind and temperature sensing systems. Repeated UAS temperature profiles give detailed insight into the temporal evolution of the SBL, which we find was often subject to rapid temperature changes affecting the entire depth of the SBL. We further highlight the potential of the sampled data by detailed investigations of a case study, featuring rapid shifts in turbulent regimes and strong elevated thermal instabilities, which were likely to result from the instability of an elevated internal gravity wave. In Paper II we assess the quality and intercomparability of UAS-based atmospheric observations from the most extensive intercomparison experiment to date. We evaluate the precision and bias of temperature, humidity, pressure, wind speed and direction observations from 38 individual UAS with 23 unique sensor configurations based on observations next to a 18-m mast equipped with reference instruments. In addition, we investigate the influence of sensor response on the quality of temperature and humidity profiles. By grouping the different sensor–platform combinations with respect to the type of aircraft, sensor type and sensor integration (i.e., measures for aspiration and radiation shielding), we attempt to draw general conclusions from the intercomparison results. Overall, we find most observation systems in good agreement with the reference observations, however, some systems showed fairly large biases. In general, hovering multicopters showed less variability than fixed-wing systems and we attribute this finding to the difference in sampling strategies. The most consistent observations of the mean wind were achieved by multicopter-mounted sonic anemometers. Sensor response errors were smaller for fine-bed thermistors compared to temperature sensors of integrated-circuit type, and sensor aspiration proofed to be substantially relevant. We conclude, that sensor integration considerations, like radiation shielding and aspiration, are likely to be as important as the choice of the sensor type, and give a couple of recommendations for future perspectives on UAS-based atmospheric measurements. Paper III presents the ISOBAR project to a broader scientific audience, including a description of the two measurement campaigns, ISOBAR17 and ISOBAR18 and the contrasting meteorological and sea ice conditions. We further provide an overview on the micrometeorological conditions during the 13 intensive observational periods (IOPs), which resulted in detailed data sets on the SBL in unprecedented spatiotemporal resolution. Numerous cases with very-stable stratification under clear-sky and weak-wind conditions were observed, featuring a variety of different SBL processes. These processes resulted in rapid changes in the SBL’s vertical structure. Based on selected in-depth case studies, we investigate the interactions of turbulence in the very stable boundary layer (VSBL) with different processes, i.e., a shear instability, associated with a low-level jet; a rapid and strong cooling event, observed a couple of meters above the ground; and a wave-breaking event, caused by the enhancement of wind shear. In a first qualitative model validation experiment we use data from one IOP to assess the performance of three different types of numerical models. Only the turbulence resolving large-eddy simulation model is found capable of reproducing a VSBL structure similar to the one observed during the IOP. The other models, i.e., an operational weather prediction and a single-column model, substantially overestimated the depth of the SBL. Paper IV introduces a new fixed-wing UAS for turbulence observations and first results from validation experiments carried out during ISOBAR18. Airborne observations of mechanical turbulence from straight horizontal flight paths are compared to corresponding eddy-covariance measurements mounted on a 10-m mast during weakly stable conditions with moderate wind speeds. Different average and spectral turbulence quantities, as well as mean wind speed and direction were computed for both systems and compared to each other. The UAS observations of mean wind and turbulence are in good agreement with the reference observations and the turbulence spectra agree qualitatively in the onset of the inertial subrange and the turbulence production range. Minor differences are likely to be caused by a slightly elevated UAS flight level and additional small altitude variations in the presence of relatively strong vertical gradients. In a second comparison, vertical profiles of mean wind and turbulence variables, determined from straight horizontal UAS flights at several different levels are compared qualitatively to profile observations from the 10-m mast and a phased-array sodar system providing 10-min averaged wind and vertical velocity variance profiles above 35 m. Qualitatively, the results agree well for the first two out of three profiles. During the third profile, the UAS data indicate the existence of a low-level jet but not an upside-down boundary layer structure, which would be expected due to the elevated source of turbulence. This observation is, however, not supported by the other measurement systems. Instead, the sodar data indicate a strong decrease in wind speed during the time of this profile. The fact that the lower part of the UAS profile was sampled before the start of the strongest transition, resulted in a seemingly wrong shape of the vertical profiles. This finding highlights the relevance of non-stationarity and the importance of additional reference systems for the correct interpretation of UAS sampled turbulence profiles. Paper V explores the potential of a new method to estimate profiles of turbulence variables in the SBL. In this method we apply a gradient-based scaling scheme for SBL turbulence to multicopter profiles of temperature and wind, sampled during ISOBAR18. We first validate this method by scaling turbulence observations from three levels on a 10-m mast with the corresponding scaling parameters, and comparing the resulting non- dimensional parameters to the semi-empirical stability functions proposed for this scheme. The scaled data from the three levels largely collapse to the predicted curves, however, minor differences between the three levels are evident. We attribute this discrepancy to the non-ideal observation heights for the determination of vertical gradients at the upper turbulence observation level. After the successful validation we apply this method to UAS profiles, by computing profiles of the gradient Richardson number to which we then apply the stability functions to derive turbulence variables. We demonstrate this approach based on three case studies covering a broad range of SBL conditions and boundary layer heights. Since the application of this scaling scheme is only valid within the SBL, we estimate the boundary layer height from the sodar and two different methods based on UAS data. Comparisons at the lowest levels against turbulence variables from the 10-m mast and at higher levels against a Doppler wind lidar, which also provides estimates of some turbulence variables, indicate broad agreement and physical meaningful results of this method. Supplementing the findings from the five scientific papers, this thesis also provides the detailed description on the methodology and data processing procedures, I applied for the synthesis of observations from UAS, micrometeorological masts and boundary layer remote-sensing systems. Furthermore, I present results on the validation of the different wind observation methods, using lidar wind observations as the common reference. Finally, I provide an outlook on future perspectives of SBL and UAS-based boundary-layer research, and how further developments in SBL observation strategies may benefit from recent and future developments.Doktorgradsavhandlin

Profiling a Community-Specific Function Landscape for Bacterial Peptides Through Protein-Level Meta-Assembly and Machine Learning

Small proteins, encoded by small open reading frames, are only beginning to emerge with the current advancement of omics technology and bioinformatics. There is increasing evidence that small proteins play roles in diverse critical biological functions, such as adjusting cellular metabolism, regulating other protein activities, controlling cell cycles, and affecting disease physiology. In prokaryotes such as bacteria, the small proteins are largely unexplored for their sequence space and functional groups. For most bacterial species from a natural community, the sample cannot be easily isolated or cultured, and the bacterial peptides must be better characterized in a metagenomic manner. The bacterial peptides identified from metagenomic samples can not only enrich the pool of small proteins but can also reveal the community-specific microbe ecology information from a small protein perspective. In this study, metaBP (Bacterial Peptides for metagenomic sample) has been developed as a comprehensive toolkit to explore the small protein universe from metagenomic samples. It takes raw sequencing reads as input, performs protein-level meta-assembly, and computes bacterial peptide homolog groups with sample-specific mutations. The metaBP also integrates general protein annotation tools as well as our small protein-specific machine learning module metaBP-ML to construct a full landscape for bacterial peptides. The metaBP-ML shows advantages for discovering functions of bacterial peptides in a microbial community and increases the yields of annotations by up to five folds. The metaBP toolkit demonstrates its novelty in adopting the protein-level assembly to discover small proteins, integrating protein-clustering tool in a new and flexible environment of RBiotools, and presenting the first-time small protein landscape by metaBP-ML. Taken together, metaBP (and metaBP-ML) can profile functional bacterial peptides from metagenomic samples with potential diverse mutations, in order to depict a unique landscape of small proteins from a microbial community