scholarly journals The Development of the Storm Tracker and its Applications for Atmospheric High-resolution Upper-air Observations

2020 ◽  
Author(s):  
Wei-Chun Hwang ◽  
Po-Hsiung Lin ◽  
Hungjui Yu
Keyword(s):  
Tropical Cyclones ◽  
High Frequency ◽  
Field Experiments ◽  
Severe Weather ◽  
High Temporal Resolution ◽  
Vertical Profiles ◽  
Atmospheric Sciences ◽  
Warm Bias ◽  
Atmospheric Research ◽  
Metal Shield

Abstract. In this study, we introduce a newly-developed upper-air observational instrument for atmospheric research. The Storm Tracker (or NTU mini-Radiosonde), is an ultra-lightweight (about 20 g including battery), multi-channel simultaneous capable radiosonde designed by the Department of Atmospheric Sciences at National Taiwan University. Developed since 2016, the Storm Tracker aims to provide an alternative for observation of atmospheric vertical profiles with a high temporal resolution, especially lower-level atmosphere under severe weather such as extreme thunderstorms and tropical cyclones. Two field experiments were conducted as trial runs in December 2017 and July 2018 at Wu-Chi, Taichung, Taiwan, to compare the Strom Tracker with the widely used Vaisala RS41 radiosonde. Among 53 co-launches of the Storm Tracker and Vaisala RS41 radiosondes, the raw measurements of pressure, wind speed, and wind direction are highly consistent between the Strom Tracker and Vaisala RS41. However, a significant daytime warm bias was found due to solar heating. A metal shield specifically for the Storm Tracker was thus installed and shows good mitigation for the warm biases. With the much lower costs of the sondes and the simultaneous multi-channel receiver, the Storm Tracker system has been proved to be beneficial for high-frequency observational needs in atmospheric research.

scholarly journals The development of the “Storm Tracker” and its applications for atmospheric high-resolution upper-air observations

2020 ◽  
Vol 13 (10) ◽  
pp. 5395-5406
Author(s):  
Wei-Chun Hwang ◽  
Po-Hsiung Lin ◽  
Hungjui Yu
Keyword(s):  
Tropical Cyclones ◽  
High Frequency ◽  
Field Experiments ◽  
Weather Conditions ◽  
Severe Weather ◽  
High Temporal Resolution ◽  
Vertical Profiles ◽  
Atmospheric Sciences ◽  
Atmospheric Research ◽  
Metal Shield

Abstract. In this study, we introduce a newly developed upper-air observational instrument for atmospheric research. The “Storm Tracker” is an ultra-lightweight (about 20 g including battery), multi-channel simultaneous capable radiosonde designed by the Department of Atmospheric Sciences at National Taiwan University. Developed in 2016, the Storm Tracker aims to provide an alternative for observing atmospheric vertical profiles with a high temporal resolution, especially the lower-level atmosphere under severe weather conditions such as extreme thunderstorms and tropical cyclones. Field experiments were conducted as trial runs in Wu-Chi, Taichung, Taiwan, to examine the ability of the Storm Tracker to observe the boundary layer, in addition to the intercomparison between the Storm Tracker and the widely used Vaisala RS41-SGP radiosonde. Among the co-launches of the Storm Tracker and Vaisala RS41 radiosondes, the measurements of pressure, wind speed, and wind direction are highly consistent between the measurements of the Storm Tracker and the Vaisala RS41-SGP. However, a significant daytime warm bias in the Storm Tracker was found due to solar heating. A metal shield specifically for the Storm Tracker was thus installed and showed mitigation for the warm biases and the overall variance. With the much lower costs of the radiosondes and the simultaneous multi-channel receiver, the Storm Tracker system has shown great potential for high-frequency observational needs in atmospheric research.

MODELING AND EXPERIMENTAL VERIFICATION OF AIR-THERMAL AND MICROWAVE-CONVECTIVE PRESOWING SEED TREATMENT

2020 ◽  
Vol 4 (41) ◽  
pp. 35-43
Author(s):  
ALEKSEY A. VASIL’EV ◽  
◽  
ALEKSEY N. VASIL’EV ◽  
DMITRIY BUDNIKOV ◽  
ANTON SHARKO
Keyword(s):  
High Frequency ◽  
Seed Treatment ◽  
Field Experiments ◽  
Research Purpose ◽  
Dense Layer ◽  
Technological Equipment ◽  
External Influence ◽  
Ultra High Frequency ◽  
Grain Processing ◽  
Seed Processing

The use of electrophysical influences for pre-sowing treatment of seeds is an effective way to increase their sowing quality. The use of these methods is limited by the fact that their implementation requires new technological equipment in grain processing lines. This problem is solved more easily when pre-sowing processing is performed using installations for active ventilation and grain drying. (Research purpose) The research purpose is in determining the possibility of using active ventilation units and ultra-high-frequency convective grain dryers for pre-sowing grain processing and to evaluating the effectiveness of such processing using computer modeling. (Materials and methods) It is necessary to ensure the uniformity of processing with external influence the seeds placed in a dense layer. Authors carried out pre-sowing treatment of seeds on real installations. Treated seeds were sown in experimental plots and the results of treatment were evaluated. (Results and discussion) The article presents graphs of changes in grain temperature and humidity during processing. To check the feasibility of pre-sowing treatment, authors performed modeling of air-heat and ultra-high-frequency convective seed treatment processes. Based on the results of field experiments, air-heat treatment stimulates the development of secondary plant roots, contributes to an intensive increase in the green mass of plants; ultra-high-frequency convective seed treatment allows increasing the number of productive stems in plants, the number of ears in one plant. (Conclusions) Technological equipment designed for drying and active ventilation of grain can be effectively used for pre-sowing seed processing. In the course of field experiments, it was revealed the possibility of controlling the structure of the crop using different types of external influence on seeds during their pre-sowing processing.

scholarly journals Assessment of Automatically Monitored Water Levels and Water Quality Indicators in Rivers with Different Hydromorphological Conditions and Pollution Levels in Greece

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 86
Author(s):  
Angeliki Mentzafou ◽  
George Varlas ◽  
Anastasios Papadopoulos ◽  
Georgios Poulis ◽  
Elias Dimitriou
Keyword(s):  
Water Quality ◽  
Time Series ◽  
Quality Indicators ◽  
High Frequency ◽  
Automatic Monitoring ◽  
Water Levels ◽  
High Temporal Resolution ◽  
Water Quality Indicators ◽  
Pollution Levels ◽  
Riverine Ecosystems

Water resources, especially riverine ecosystems, are globally under qualitative and quantitative degradation due to human-imposed pressures. High-temporal-resolution data obtained from automatic stations can provide insights into the processes that link catchment hydrology and streamwater chemistry. The scope of this paper was to investigate the statistical behavior of high-frequency measurements at sites with known hydromorphological and pollution pressures. For this purpose, hourly time series of water levels and key water quality indicators (temperature, electric conductivity, and dissolved oxygen concentrations) collected from four automatic monitoring stations under different hydromorphological conditions and pollution pressures were statistically elaborated. Based on the results, the hydromorphological conditions and pollution pressures of each station were confirmed to be reflected in the results of the statistical analysis performed. It was proven that the comparative use of the statistics and patterns of the water level and quality high-frequency time series could be used in the interpretation of the current site status as well as allowing the detection of possible changes. This approach can be used as a tool for the definition of thresholds, and will contribute to the design of management and restoration measures for the most impacted areas.

Variations in High-frequency Oscillations of Tropical Cyclones over the Western North Pacific

2018 ◽  
Vol 35 (4) ◽  
pp. 423-434
Author(s):  
Shumin Chen ◽  
Weibiao Li ◽  
Zhiping Wen ◽  
Mingsen Zhou ◽  
Youyu Lu ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
North Pacific ◽  
High Frequency ◽  
Western North Pacific ◽  
High Frequency Oscillations

scholarly journals Detecting gas leakage using high-frequency signals generated by air-gun arrays

Geophysics ◽  
2017 ◽  
Vol 82 (2) ◽  
pp. A7-A12 ◽  
Author(s):  
Martin Landrø ◽  
Fredrik Hansteen ◽  
Lasse Amundsen
Keyword(s):  
High Frequency ◽  
Field Experiments ◽  
Water Layer ◽  
Sampling Interval ◽  
Acoustic Energy ◽  
Storage Site ◽  
High Frequency Signal ◽  
Gas Leakage ◽  
Temporal Sampling ◽  
Air Gun

Recent field experiments have demonstrated that marine air-gun arrays create acoustic energy greater than 1 kHz. We have suggested to use the high-frequency signal as a source to look for gas leakage at, for instance, a producing hydrocarbon field, or a [Formula: see text] storage site in which the field is covered by permanent acoustic sensors at the seabed, often referred to as a permanent reservoir monitoring field. The only needed modification is that the temporal sampling interval for the receivers is decreased to 0.1 ms (in contrast to the normal sampling interval of 1 or 2 ms), to ensure that the system is capable of recording signals up to 5 kHz. We suggest using numerous fixed receivers at the seabed to detect a gas chimney by simple high-pass filtering and subsequent transmission type analysis of the recorded signals. We think this method might serve as an elegant, precise, and very cost-effective way to detect gas leakage into the water layer.

scholarly journals The Estimation of Hydrometeor Profiles from Wideband Microwave Observations

2000 ◽  
Vol 39 (10) ◽  
pp. 1645-1656 ◽  
Author(s):  
Gail M. Skofronick-Jackson ◽  
James R. Wang
Keyword(s):  
High Frequency ◽  
Cloud Water ◽  
Tropical Ocean ◽  
Low Frequencies ◽  
High Frequencies ◽  
Atmospheric Research ◽  
Brightness Temperatures ◽  
Microphysical Properties ◽  
Ice Microphysics ◽  
Updraft Region

Abstract Profiles of the microphysical properties of clouds and rain cells are essential in many areas of atmospheric research and operational meteorology. To enhance the understanding of the nonlinear and underconstrained relationships between cloud and hydrometeor microphysical profiles and passive microwave brightness temperatures, estimations of cloud profiles for an anvil region, a convective region, and an updraft region of an oceanic squall were performed. The estimations relied on comparisons between radiative transfer calculations of incrementally estimated microphysical profiles and concurrent dual-altitude wideband brightness temperatures from the 22 February 1993 flight during the Tropical Ocean and Global Atmosphere Coupled Ocean–Atmosphere Response Experiment. The wideband observations (10–220 GHz) are necessary for estimating cloud profiles reaching up to 20 km. The low frequencies enhance the rain and cloud water profiles, and the high frequencies are required to detail the higher-altitude ice microphysics. A microphysical profile was estimated for each of the three regions of the storm. Each of the three estimated profiles produced calculated brightness temperatures within ∼10 K of the observations. A majority of the total iterative adjustments were to the estimated profile’s frozen hydrometeor characteristics and were necessary to match the high-frequency calculations with the observations. This requirement indicates a need to validate cloud-resolving models using high frequencies. Some difficulties matching the 37-GHz observation channels on the DC-8 and ER-2 aircraft with the calculations simulated at the two aircraft heights (∼11 km and 20 km, respectively) were noted, and potential causes were presented.

scholarly journals Ecologically safe methods for presowing treatment of cereal seeds

2019 ◽  
Vol 9 (3) ◽  
pp. 198-207
Author(s):  
V. V. Bezpal'ko ◽  
L. V. Zhukova ◽  
S. V. Stankevich ◽  
Yu. H. Ogurtsov ◽  
I. I. Klymenko ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Seed Production ◽  
High Frequency ◽  
Field Experiments ◽  
Spring Barley ◽  
Ecological Features ◽  
Extremely High Frequency ◽  
Presowing Treatment ◽  
Before And After ◽  
Crop Capacity

We analyzed various sources of scientific literature and our data at the experimental field of the National Academy of Agrarian Sciences Plant Growing Institute named after V.Ya. Yuryev within 2010-2013. The irradiation of winter wheat and spring barley seeds with the electromagnetic fields of the extremely high frequencies (MWF of EHF) was carried out with the help of the equipment of the Kharkiv Technical University of Radio Electronics. The treatment of seeds with the microwave oscillations of the extremely high frequency electromagnetic field (MWF of EHF) that is widely used for the operation of many radio and home microwave devices was done at the frequency range of 2.5-3.4 GHz, at the power of 0.9-1.8 kW for 5-95 seconds per 1 kg of seeds. The sowing quality of the seeds before and after treatment was determined in accordance with the current State Standard of Ukraine 4138-2002 in the laboratory of the seed production and seed science of the Plant Growing Institute named after V.Ya. Yuryev. The field experiments were performed in the crop rotation laboratory of the seed production and seed science. Pea for grain was sown before spring barley and the black fallow preceded winter wheat. During the experiments the area of the studied plot was 20 m2, the recurrence was four-times, and the placement of the plots were systemic.We suggested the optimum regimes of seeds irradiation with the microwave field of an extremely high frequency (MWF of EHF). They should be at range of 2.4-3.4 GHz with the power consumption of 0.9 kW per 1 kg of seed and at exposure of 45 seconds of 1.8 kW per 1 kg of seeds and exposure of 15-20 seconds. Such regimes cause the increased energy of germination, seeds sprouting, and crop capacity. We proposed to use this solution for improving and increasing the ecological features of winter wheat and spring barley by using the presowing microwave irradiation of seeds instead of chemical treatment. We considered the complex presowing treatment of seeds with MWF of EHF in combination with the plant growth regulators should be adopted and further enhanced.

scholarly journals Opto-Mechanical Inertial Sensors (OMIS) for High Temporal Resolution Gravimetry

2020 ◽  
Author(s):  
Lee Kumanchik ◽  
Felipe Guzman ◽  
Claus Braxmaier
Keyword(s):  
High Frequency ◽  
High Stability ◽  
Vibration Isolation ◽  
Inertial Sensors ◽  
Response Times ◽  
Free Spectral Range ◽  
Optical Cavity ◽  
Fused Silica ◽  
High Temporal Resolution ◽  
Free Falling

<p>Gravity field measurement by free-falling atoms has the potential for very high stability<br>over time as the measurement exposes a direct, fundamental relationship between mass<br>and acceleration. However, the measurement rate of the current state-of-the-art limits<br>the performance at short timescales (greater than 1 Hz). Classical inertial sensors operate<br>at much faster response times and are thus natural companions for free-falling atom<br>sensors. Such a hybrid device would gain the ultra-high stability of the free-falling atom<br>sensor while greatly extending the bandwidth to higher frequency using the classical<br>sensor. This requires the stable bandwidth of both devices to overlap sufficiently. We<br>have developed opto-mechanical inertial sensors (OMIS) with good long term stability for<br>just this purpose. The sensors are made of highly stable fused silica material, feature a<br>monolithic optical cavity for displacement readout, and utilize a laser diode stabilized to<br>a molecular reference. With no temperature control and only the thermal shielding<br>provided by the vacuum chamber, this device is stable down to 0.1 Hz which overlaps<br>with the bandwidth of free-falling atom sensors. The OMIS are self-calibrating by<br>converting the fundamental resonances of a molecular gas into length using the<br>free-spectral range of the optical cavity,  <em>FSR = c/2nL</em>,  and then sampling the OMIS<br>mechanical damping rate and resonance frequency using a nearby piezo. This<br>acceleration calibration is potentially transferable to a companion free-falling atom<br>sensor. Readout is performed by modulating the cavity length of the OMIS with one<br>cavity mirror being the OMIS itself and the other being a high frequency resonator. The<br>high frequency resonator is driven by a nearby piezo well above the response rate of the<br>OMIS and acts like an ultrastable quartz clock. The resulting highly stable tone is<br>demodulated by the readout electronics. For the low finesse optical cavity used here, this<br>yields a displacement resolution of 2x10<sup>-13</sup> m/√Hz and a high frequency acceleration<br>resolution of 400 n<em>g</em> /√Hz. At 0.1 Hz the acceleration resolution is 1.5 μ<em>g</em> /√Hz limited by<br>the stability of our vibration isolation stage. The OMIS dimensions are about 30 mm x 30<br>mm x 5 mm and can be fiber coupled to enable co-location with other sensors or as<br>standalone devices for future gravimetry both on Earth and in space</p>

scholarly journals An Effective Similar-Pixel Reconstruction of the High-Frequency Cloud-Covered Areas of Southwest China

2019 ◽  
Vol 11 (3) ◽  
pp. 336 ◽  
Author(s):  
Wenping Yu ◽  
Junlei Tan ◽  
Mingguo Ma ◽  
Xiaolu Li ◽  
Xiaojun She ◽  
...  
Keyword(s):  
Land Surface ◽  
High Frequency ◽  
Southwest China ◽  
Global Climate ◽  
Average Error ◽  
Balance Theory ◽  
High Temporal Resolution ◽  
Retrieval Accuracy ◽  
Southwest Region

With advantages of multispatial resolutions, a high retrieval accuracy, and a high temporal resolution, the satellite-derived land surface temperature (LST) products are very important LST sources. However, the greatest barrier to their wide application is the invalid values produced by large quantities of cloudy pixels, especially for regions frequently swathed in clouds. In this study, an effective method based on the land energy balance theory and similar pixels (SP) method was developed to reconstruct the LSTs over cloudy pixels for the widely used MODIS LST (MOD11A1). The southwest region of China was selected as the study area, where extreme drought has frequently occurred in recent years in the context of global climate change and which commonly exhibits cloudy and foggy weather. The validation results compared with in situ LSTs showed that the reconstructed LSTs have an average error < 1.00 K (0.57 K at night and -0.14 K during the day) and an RMSE < 3.20 K (1.90 K at night and 3.16 K in the daytime). The experiment testing the SP interpolation indicated that the spatial structure of the LST has a greater effect on the SP performance than the size of the data-missing area, which benefits the LST reconstruction in the area frequently covered by large clouds.

scholarly journals Turbulence fluxes and variances measured with a sonic anemometer mounted on a tethered balloon

2016 ◽  
Vol 9 (9) ◽  
pp. 4375-4386 ◽  
Author(s):  
Guylaine Canut ◽  
Fleur Couvreux ◽  
Marie Lothon ◽  
Dominique Legain ◽  
Bruno Piguet ◽  
...  
Keyword(s):  
Boundary Layer ◽  
High Frequency ◽  
Field Experiments ◽  
Sonic Anemometer ◽  
Motion Sensor ◽  
Tethered Balloon ◽  
Inertial Motion ◽  
Convective Boundary ◽  
Momentum Fluxes ◽  
Field Campaigns

Abstract. This study presents the first deployment in field campaigns of a balloon-borne turbulence probe, developed with a sonic anemometer and an inertial motion sensor suspended below a tethered balloon. This system measures temperature and horizontal and vertical wind at high frequency and allows the estimation of heat and momentum fluxes as well as turbulent kinetic energy in the lower part of the boundary layer. The system was validated during three field experiments with different convective boundary-layer conditions, based on turbulent measurements from instrumented towers and aircraft.

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