scholarly journals Bi-Spectral Infrared Algorithm for Cloud Coverage over Oceans by the JEM-EUSO Mission Program

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6506
Author(s):  
David Santalices ◽  
Susana Briz ◽  
Antonio J. de Castro ◽  
Fernando López
Keyword(s):  
Brightness Temperature ◽  
Ad Hoc ◽  
Low Cost ◽  
Infrared Camera ◽  
Cosmic Ray ◽  
High Energy ◽  
Ir Camera ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Difference ◽  
Split Window Algorithm

The need to monitor specific areas for different applications requires high spatial and temporal resolution. This need has led to the proliferation of ad hoc systems on board nanosatellites, drones, etc. These systems require low cost, low power consumption, and low weight. The work we present follows this trend. Specifically, this article evaluates a method to determine the cloud map from the images provided by a simple bi-spectral infrared camera within the framework of JEM-EUSO (The Joint Experiment Missions-Extrem Universe Space Observatory). This program involves different experiments whose aim is determining properties of Ultra-High Energy Cosmic Ray (UHECR) via the detection of atmospheric fluorescence light. Since some of those projects use UV instruments on board space platforms, they require knowledge of the cloudiness state in the FoV of the instrument. For that reason, some systems will include an infrared (IR) camera. This study presents a test to generate a binary cloudiness mask (CM) over the ocean, employing bi-spectral IR data. The database is created from Moderate-Resolution Imaging Spectroradiometer (MODIS) data (bands 31 and 32). The CM is based on a split-window algorithm. It uses an estimation of the brightness temperature calculated from a statistical study of an IR images database along with an ancillary sea surface temperature. This statistical procedure to obtain the estimate of the brightness temperature is one of the novel contributions of this work. The difference between the measured and estimation of the brightness temperature determines whether a pixel is cover or clear. That classification requires defining several thresholds which depend on the scenarios. The procedure for determining those thresholds is also novel. Then, the results of the algorithm are compared with the MODIS CM. The agreement is above 90%. The performance of the proposed CM is similar to that of other studies. The validation also shows that cloud edges concentrate the vast majority of discrepancies with the MODIS CM. The relatively high accuracy of the algorithm is a relevant result for the JEM-EUSO program. Further work will combine the proposed algorithm with complementary studies in the framework of JEM-EUSO to reinforce the CM above the cloud edges.

A Physically Based Algorithm for Non-Blackbody Correction of Cloud-Top Temperature and Application to Convection Study

2014 ◽  
Vol 53 (7) ◽  
pp. 1844-1857 ◽  
Author(s):  
Chunpeng Wang ◽  
Zhengzhao Johnny Luo ◽  
Xiuhong Chen ◽  
Xiping Zeng ◽  
Wei-Kuo Tao ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Weighting Function ◽  
Convective Cloud ◽  
Transfer Model ◽  
Height Range ◽  
Convective Clouds ◽  
Physically Based ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Difference ◽  
Cloud Top Temperature

AbstractCloud-top temperature (CTT) is an important parameter for convective clouds and is usually different from the 11-μm brightness temperature due to non-blackbody effects. This paper presents an algorithm for estimating convective CTT by using simultaneous passive [Moderate Resolution Imaging Spectroradiometer (MODIS)] and active [CloudSat + Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)] measurements of clouds to correct for the non-blackbody effect. To do this, a weighting function of the MODIS 11-μm band is explicitly calculated by feeding cloud hydrometer profiles from CloudSat and CALIPSO retrievals and temperature and humidity profiles based on ECMWF analyses into a radiation transfer model. Among 16 837 tropical deep convective clouds observed by CloudSat in 2008, the averaged effective emission level (EEL) of the 11-μm channel is located at optical depth ~0.72, with a standard deviation of 0.3. The distance between the EEL and cloud-top height determined by CloudSat is shown to be related to a parameter called cloud-top fuzziness (CTF), defined as the vertical separation between −30 and 10 dBZ of CloudSat radar reflectivity. On the basis of these findings a relationship is then developed between the CTF and the difference between MODIS 11-μm brightness temperature and physical CTT, the latter being the non-blackbody correction of CTT. Correction of the non-blackbody effect of CTT is applied to analyze convective cloud-top buoyancy. With this correction, about 70% of the convective cores observed by CloudSat in the height range of 6–10 km have positive buoyancy near cloud top, meaning clouds are still growing vertically, although their final fate cannot be determined by snapshot observations.

scholarly journals Forecasting and communication key elements for low-cost fluvial flooding early warning system in urban areas

2021 ◽  
Vol 11 (5) ◽  
pp. 4143
Author(s):  
Melisa Acosta-Coll ◽  
Andres Solano-Escorcia ◽  
Lilia Ortega-Gonzalez ◽  
Ronald Zamora-Musa
Keyword(s):  
Power Consumption ◽  
Early Warning ◽  
Urban Areas ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Communication Protocols ◽  
Warning System ◽  
Early Warning Systems ◽  
High Energy ◽  
The Difference

Fluvial flooding occurs when a river overspills its banks due to excessive rainfall, and it is the most common flood event. In urban areas, the increment of urbanization makes communities more susceptible to fluvial flooding since the excess of impervious surfaces reduced the natural permeable areas. As flood prevention strategies, early warning systems (EWS) are used to reduce damage and protect people, but key elements need to be selected. This manuscript proposes the monitoring instruments, communication protocols, and media to forecast and disseminate EWS alerts efficiently during fluvial floods in urban areas. First, we conducted a systematic review of different EWS architectures for fluvial floods in urban areas and identified that not all projects monitor the most important variables related to the formation of fluvial floods and most use communication protocols with high-energy consumption. ZigBee and LoRaWAN are the communication protocols with lower power consumption from the review, and to determine which technology has better performance in urban areas, two wireless sensor networks were deployed and simulated in two urban areas susceptible to fluvial floods using Radio Mobile software. The results showed that although Zigbee technology has better-received signal strength, the difference with LoRAWAN is lower than 2 dBm, but LoRaWAN has a better signal-to-noise ratio, power consumption, coverage, and deployment cost.

scholarly journals The nature of the penetrating component of cosmic rays

1938 ◽  
Vol 165 (920) ◽  
pp. 11-31 ◽  
Author(s):  
Patrick Maynard Stuart Blackett
Keyword(s):  
Energy Loss ◽  
Average Energy ◽  
Great Majority ◽  
Cosmic Ray ◽  
High Energy ◽  
Transition Curve ◽  
Metal Plates ◽  
The Difference ◽  
Normal Electron ◽  
Transition Curves

The measurements by Neddermeyer and Anderson (1937) of the absorp­tion of cosmic-ray particles of low energy by metal plates differ in certain respects from those by Blackett and Wilson (1937). The former results showed that, in the energy range 1∙2 x 10 8 to 5 x 10 8 e-volts, two types of particles exist, an absorbable group assumed to behave as theory predicts of electrons and a much more penetrating group, attributed provisionally to heavier particles. On the other hand, we found that all the rays with energy under 2 x 10 8 e-volts were absorbed like electrons, while for rays of greater energy the average energy loss was very much less. Though a very few energetic particles were found to have a high energy loss, insufficient evidence was then available to justify classifying them as of a nature distinct from the less absorbable rays. Thus we obtained definite experimental evidence that the energy loss of the great majority of the rays varies rapidly with their energy. We concluded, therefore, that the energy loss of a normal electron varies with its energy. We now believe this to be probably false, since the success of the cascade theory of showers, in explaining the transition curve in the atmosphere, and a large part, at any rate, of the phenomena of the transition curves of showers and bursts, has provided fairly strong evidence that there must be a very few energetic rays at sea-level, which have the full radiation loss of electrons, even in heavy elements. It follows that the great majority of the rays, for which the energy loss certainly varies rapidly with energy, are probably not normal electrons. We therefore agree with the view of Neddermeyer and Anderson that it is likely that there are two types of particles present, though the difference in behaviour only exists for energies over 2 x 10 8 e-volts.

scholarly journals Starburst Energy Feedback Seen through HCO+/HOC+ Emission in NGC 253 from ALCHEMI

2021 ◽  
Vol 923 (1) ◽  
pp. 24
Author(s):  
Nanase Harada ◽  
Sergio Martín ◽  
Jeffrey G. Mangum ◽  
Kazushi Sakamoto ◽  
Sebastien Muller ◽  
...  
Keyword(s):  
Galactic Center ◽  
Cosmic Ray ◽  
Ionization Rate ◽  
High Energy ◽  
Photon Flux ◽  
Starburst Galaxy ◽  
Energy Feedback ◽  
The Difference ◽  
Uv Photons ◽  
Molecular Abundances

Abstract Molecular abundances are sensitive to the UV photon flux and cosmic-ray ionization rate. In starburst environments, the effects of high-energy photons and particles are expected to be stronger. We examine these astrochemical signatures through multiple transitions of HCO+ and its metastable isomer HOC+ in the center of the starburst galaxy NGC 253 using data from the Atacama Large Millimeter/submillimeter Array large program ALMA Comprehensive High-resolution Extragalactic Molecular inventory. The distribution of the HOC+(1−0) integrated intensity shows its association with “superbubbles,” cavities created either by supernovae or expanding H ii regions. The observed HCO+/HOC+ abundance ratios are ∼10–150, and the fractional abundance of HOC+ relative to H2 is ∼1.5 × 10−11–6 × 10−10, which implies that the HOC+ abundance in the center of NGC 253 is significantly higher than in quiescent spiral arm dark clouds in the Galaxy and the Galactic center clouds. Comparison with chemical models implies either an interstellar radiation field of G 0 ≳ 103 if the maximum visual extinction is ≳5, or a cosmic-ray ionization rate of ζ ≳ 10−14 s−1 (3–4 orders of magnitude higher than that within clouds in the Galactic spiral arms) to reproduce the observed results. From the difference in formation routes of HOC+, we propose that a low-excitation line of HOC+ traces cosmic-ray dominated regions, while high-excitation lines trace photodissociation regions. Our results suggest that the interstellar medium in the center of NGC 253 is significantly affected by energy input from UV photons and cosmic rays, sources of energy feedback.

The use of solid iron magnets in the study of nuclear-active particles

1968 ◽  
Vol 46 (10) ◽  
pp. S1130-S1134
Author(s):  
R. M. Bull ◽  
W. F. Nash ◽  
J. K. Haywood
Keyword(s):  
Low Cost ◽  
Cosmic Ray ◽  
High Energy ◽  
Strong Interactions ◽  
Active Particles ◽  
Solid Iron ◽  
High Fields

Solid iron magnets have found increasing use in experiments requiring momentum measurements on high-energy μ mesons. Such magnets enable high fields to be produced over very large volumes at very low cost and are consequently particularly attractive for cosmic-ray studies. They have not been used, however, for measurements on particles exhibiting strong interactions. This paper describes the possibilities of using multiple solid iron magnets for this purpose and analyzes some of their characteristics.

Improvement of GPS and GLONASS Positioning Accuracy by Multipath Mitigation Using Omnidirectional Infrared Camera

2011 ◽  
Vol 23 (6) ◽  
pp. 1125-1131 ◽  
Author(s):  
Mitsunori Kitamura ◽  
◽  
Taro Suzuki ◽  
Yoshiharu Amano ◽  
Takumi Hashizume
Keyword(s):  
Mobile Robots ◽  
Infrared Camera ◽  
Multipath Mitigation ◽  
Positioning Accuracy ◽  
Ir Camera ◽  
Multipath Error ◽  
Satellite Positioning ◽  
Positioning Technique ◽  
The Difference ◽  
Atmospheric Transmittance

This paper describes a precision positioning technique that can be applied to vehicles or mobile robots in urban or leafy environments. The availability of satellite positioning is currently expected to improve due to the presence of positioning satellites such as US GPS, Russia’s Glonass and Europe’s Galileo. Due to the serious multipath impact on positioning accuracy in urban or leafy areas, however, improvements in satellite positioning availability do not necessarily facilitate highprecision positioning. Our proposed technique mitigates the GPS and Glonass multipath using an omnidirectional infrared (IR) camera that can eliminate the need for invisible satellites using IR images. With an IR camera, the sky appears distinctively dark. This facilitates the detection of the borderline between the sky and surrounding buildings and foliage due to the difference in atmospheric transmittance between visible light and IR rays, since buildings and foliage appear white. The proposed technique can automatically and robustly mitigate the GPS and Glonass multipath by excluding invisible satellites. Positioning was evaluated with visible satellites, which have less multipath error and without using invisible satellites. Evaluation results confirmed the effectiveness of the proposed technique and the feasibility of its highly accurate positioning.

Sidereal time variation of high-energy cosmic rays observed by an air Cerenkov telescope

1968 ◽  
Vol 46 (10) ◽  
pp. S607-S610 ◽  
Author(s):  
Y. Sekido ◽  
K. Nagashima ◽  
I. Kondo ◽  
T. Murayama ◽  
H. Okuda ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Sidereal Time ◽  
High Energy Cosmic Rays ◽  
Four Seasons ◽  
200 Gev ◽  
The Difference ◽  
Celestial Sphere ◽  
Sidereal Anisotropy

Using the cosmic-ray telescope No. 3 (air Cerenkov telescope) at Nagoya, observations of high-energy (~200 GeV) cosmic rays were continued during the period from February 1964 to March 1966. The observations were made at a fixed zenith angle Z = 60° and at two azimuths A = 72° and 288°. With this setting, the celestial sphere was scanned in the declination band between 25° and 40 °N. Using the difference between the two diurnal vectors observed at 72° (east) and 288° (west), the anisotropy, free from any diurnal variation of meteorological origin, was obtained corresponding to each of four seasons. From these four anisotropy vectors, the solar anisotropy was found to be insignificant, but the sidereal anisotropy was as follows:[Formula: see text]

Satellite and Radar Remote Sensing of Southern Plains Grass Fires: A Case Study

2010 ◽  
Vol 49 (10) ◽  
pp. 2133-2146 ◽  
Author(s):  
Thomas A. Jones ◽  
Sundar A. Christopher
Keyword(s):  
Remote Sensing ◽  
Brightness Temperature ◽  
Cross Sections ◽  
Radar Data ◽  
Southern Plains ◽  
Smoke Plumes ◽  
Fire Debris ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Difference ◽  
The Individual

Abstract Many large grass fires occurred in north Texas and southern Oklahoma on 9 April 2009, destroying hundreds of homes and businesses and burning thousands of acres of grasslands, producing large smoke and debris plumes that were visible from various remote sensing platforms. At the same time, strong westerly winds were transporting large amounts of dust into the region, mixing with the smoke and debris already being generated. This research uses surface- and satellite-based remote sensing observations of this event to assess the locations of fires and the spatial distribution of smoke and dust aerosols. The authors present a unique perspective by analyzing radar observations of fire debris in conjunction with the satellite analysis of submicrometer smoke aerosol particles. Satellite data clearly show the location of the individual fires and the downwind smoke plumes as well as the large dust storm present over the region. In particular, Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical thickness at 0.55 μm within the dust plume was around 0.5, and it increased to greater than 1.0 when combined with smoke. Using the difference in 11- versus 12-μm brightness temperature data combined with surface observations, the large extent of the dust plume was evident through much of north-central Texas, where visibilities were low and the 11–12-μm brightness temperature difference was negative. Conversely, smoke plumes were characterized by higher reflectance at 0.6 μm (visible wavelength). Cross sections of radar data through the several smoke and debris plumes indicated the burnt debris reached up to 5 km into the atmosphere. Plume height output from modified severe storm algorithms produced similar values. Since smoke aerosols are smaller and lighter when compared with the debris, they were likely being transported even higher into the atmosphere. These results show that the combination of satellite and radar data offers a unique perspective on observing the characteristics and evolution of smoke and debris plume emanating from grass fire events.

Janus – A New Approach to Air Combat Pilot Training

2019 ◽  
Vol 2019 (4) ◽  
pp. 7-22
Author(s):  
Georges Bridel ◽  
Zdobyslaw Goraj ◽  
Lukasz Kiszkowiak ◽  
Jean-Georges Brévot ◽  
Jean-Pierre Devaux ◽  
...  
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
High Energy ◽  
Training System ◽  
Embedded Sensors ◽  
Pilot Training ◽  
New Approach ◽  
Combat Aircraft ◽  
Air Combat ◽  
The Cost

Abstract Advanced jet training still relies on old concepts and solutions that are no longer efficient when considering the current and forthcoming changes in air combat. The cost of those old solutions to develop and maintain combat pilot skills are important, adding even more constraints to the training limitations. The requirement of having a trainer aircraft able to perform also light combat aircraft operational mission is adding unnecessary complexity and cost without any real operational advantages to air combat mission training. Thanks to emerging technologies, the JANUS project will study the feasibility of a brand-new concept of agile manoeuvrable training aircraft and an integrated training system, able to provide a live, virtual and constructive environment. The JANUS concept is based on a lightweight, low-cost, high energy aircraft associated to a ground based Integrated Training System providing simulated and emulated signals, simulated and real opponents, combined with real-time feedback on pilot’s physiological characteristics: traditionally embedded sensors are replaced with emulated signals, simulated opponents are proposed to the pilot, enabling out of sight engagement. JANUS is also providing new cost effective and more realistic solutions for “Red air aircraft” missions, organised in so-called “Aggressor Squadrons”.

scholarly journals Diffuse γ-ray emission toward the massive star-forming region, W40

2020 ◽  
Vol 639 ◽  
pp. A80
Author(s):  
Xiao-Na Sun ◽  
Rui-Zhi Yang ◽  
Yun-Feng Liang ◽  
Fang-Kun Peng ◽  
Hai-Ming Zhang ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
High Energy ◽  
Young Star ◽  
Gas Content ◽  
Large Area ◽  
Stellar Cluster ◽  
Production Region ◽  
Star Forming ◽  
Photon Index ◽  
Young Star Clusters

We report the detection of high-energy γ-ray signal towards the young star-forming region, W40. Using 10-yr Pass 8 data from the Fermi Large Area Telescope (Fermi-LAT), we extracted an extended γ-ray excess region with a significance of ~18σ. The radiation has a spectrum with a photon index of 2.49 ± 0.01. The spatial correlation with the ionized gas content favors the hadronic origin of the γ-ray emission. The total cosmic-ray (CR) proton energy in the γ-ray production region is estimated to be the order of 1047 erg. However, this could be a small fraction of the total energy released in cosmic rays (CRs) by local accelerators, presumably by massive stars, over the lifetime of the system. If so, W40, together with earlier detections of γ-rays from Cygnus cocoon, Westerlund 1, Westerlund 2, NGC 3603, and 30 Dor C, supports the hypothesis that young star clusters are effective CR factories. The unique aspect of this result is that the γ-ray emission is detected, for the first time, from a stellar cluster itself, rather than from the surrounding “cocoons”.

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