scholarly journals Initial Assessment of the COSMIC-2/FORMOSAT-7 Neutral Atmosphere Data Quality in NESDIS/STAR Using In Situ and Satellite Data

2020 ◽  
Vol 12 (24) ◽  
pp. 4099
Author(s):  
Shu-Peng Ho ◽  
Xinjia Zhou ◽  
Xi Shao ◽  
Bin Zhang ◽  
Loknath Adhikari ◽  
...  
Keyword(s):  
Water Vapor ◽  
Data Quality ◽  
Signal To Noise Ratio ◽  
Initial Assessment ◽  
Observation System ◽  
Neutral Atmosphere ◽  
Satellite Mission ◽  
Radiosonde Observation ◽  
Satellite Applications ◽  
The Mean

A COSMIC-1/FORMOSAT-3 (Constellation Observing System for Meteorology, Ionosphere, and Climate-1 and Formosa Satellite Mission 3) follow-on mission, COSMIC-2/FORMOSAT-7, had been successfully launched into low-inclination orbits on 25 June 2019. COSMIC-2 has a significantly increased Signal-to-Noise ratio (SNR) compared to other Radio Occultation (RO) missions. This study summarized the initial assessment of COSMIC-2 data quality conducted by the NOAA (National Oceanic and Atmospheric Administration) Center for Satellite Applications and Research (STAR). We use validated data from other RO missions to quantify the stability of COSMIC-2. In addition, we use the Vaisala RS41 radiosonde observations to assess the accuracy and uncertainty of the COSMIC-2 neutral atmospheric profiles. RS41 is currently the most accurate radiosonde observation system. The COSMIC-2 SNR ranges from 200 v/v to about 2800 v/v. To see if the high SNR COSMIC-2 signals lead to better retrieval results, we separate the COSMIC-2–RS41 comparisons into different SNR groups (i.e., 0–500 v/v group, 500–1000 v/v group, 1000–1500 v/v group, 1500–2000 v/v group, and >2000 v/v group). In general, the COSMIC-2 data quality in terms of stability, precision, accuracy, and uncertainty of the accuracy is very compatible with those from COSMIC-1. Results show that the mean COSMIC-2–RS41 water vapor difference from surface to 5 km altitude for each SNR groups are equal to −1.34 g/kg (0–500 v/v), −1.17 g/kg (500–1000 v/v), −1.33 g/kg (1000–1500 v/v), −0.93 g/kg (1500–2000 v/v), and −1.52 g/kg (>2000 v/v). Except for the >2000 v/v group, the high SNR measurements from COSMIC-2 seem to improve the mean water vapor difference for the higher SNR group slightly (especially for the 1500–2000 v/v group) comparing with those from lower SNR groups.

scholarly journals A porous PDMS pulsewave sensor with haircell structures for water vapor transmission rate and signal-to-noise ratio enhancement

2021 ◽  
Author(s):  
Minho Seok ◽  
Sunghyun Yoon ◽  
Mookyum Kim ◽  
Young-Ho Cho
Keyword(s):  
Water Vapor ◽  
Transmission Rate ◽  
Signal To Noise Ratio ◽  
Water Vapor Transmission Rate ◽  
Signal To Noise ◽  
Water Vapor Transmission ◽  
Noise Ratio

We present a porous polydimethylsiloxane (PDMS) pulsewave sensor with haircell structures that improves both water vapor transmission rate (WVTR) and signal-to-noise ratio (SNR).

scholarly journals Monitoring and prediction of hurricane tracks using GPS tropospheric products

GPS Solutions ◽  
2021 ◽  
Vol 25 (2) ◽  
Author(s):  
Yohannes Getachew Ejigu ◽  
Felix Norman Teferle ◽  
Anna Klos ◽  
Bogusz Janusz ◽  
Addisu Hunegnaw
Keyword(s):  
Water Vapor ◽  
Satellite Mission ◽  
Additional Resource ◽  
Spatial And Temporal Distributions ◽  
Zenith Wet Delay ◽  
The Usa ◽  
Hurricane Tracks

AbstractWe have reconstructed integrated water vapor (IWV) using the zenith wet delays to track the properties of hurricanes and explore their spatial and temporal distributions estimated from 922 GPS stations. Our results show that a surge in GPS-derived IWV occurred at least six hours prior to the landfall of two major hurricanes (Harvey and Irma) that struck the Gulf and East Coasts of the USA in 2017. We observed enhanced IWV, in particular, for the two hurricanes landfall locations. The observed variations exhibit a correlation with the precipitation value constructed from GPM/IMERG satellite mission coinciding with hurricane storm front passage. We used GPS-IWV data as inputs for spaghetti line plots for our path predictions, helping us predict the paths of Hurricanes Harvey and Irma. Hence, a directly estimable zenith wet delay sourced from GPS that has not been previously reported can serve as an additional resource for improving the monitoring of hurricane paths.

scholarly journals Optimization of SPECT/CT imaging protocols for quantitative and qualitative 99mTc SPECT

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Dennis Kupitz ◽  
Heiko Wissel ◽  
Jan Wuestemann ◽  
Stephanie Bluemel ◽  
Maciej Pech ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Quantitative Imaging ◽  
Scatter Correction ◽  
Reconstruction Algorithm ◽  
Weighting Factor ◽  
Quantitative Spect ◽  
Pet Ct ◽  
Spect Acquisition ◽  
The Mean ◽  
A Minor

Abstract Background The introduction of hybrid SPECT/CT devices enables quantitative imaging in SPECT, providing a methodological setup for quantitation using SPECT tracers comparable to PET/CT. We evaluated a specific quantitative reconstruction algorithm for SPECT data using a 99mTc-filled NEMA phantom. Quantitative and qualitative image parameters were evaluated for different parametrizations of the acquisition and reconstruction protocol to identify an optimized quantitative protocol. Results The reconstructed activity concentration (ACrec) and the signal-to-noise ratio (SNR) of all examined protocols (n = 16) were significantly affected by the parametrization of the weighting factor k used in scatter correction, the total number of iterations and the sphere volume (all, p < 0.0001). The two examined SPECT acquisition protocols (with 60 or 120 projections) had a minor impact on the ACrec and no significant impact on the SNR. In comparison to the known AC, the use of default scatter correction (k = 0.47) or object-specific scatter correction (k = 0.18) resulted in an underestimation of ACrec in the largest sphere volume (26.5 ml) by − 13.9 kBq/ml (− 16.3%) and − 7.1 kBq/ml (− 8.4%), respectively. An increase in total iterations leads to an increase in estimated AC and a decrease in SNR. The mean difference between ACrec and known AC decreased with an increasing number of total iterations (e.g., for 20 iterations (2 iterations/10 subsets) = − 14.6 kBq/ml (− 17.1%), 240 iterations (24i/10s) = − 8.0 kBq/ml (− 9.4%), p < 0.0001). In parallel, the mean SNR decreased significantly from 2i/10s to 24i/10s by 76% (p < 0.0001). Conclusion Quantitative SPECT imaging is feasible with the used reconstruction algorithm and hybrid SPECT/CT, and its consistent implementation in diagnostics may provide perspectives for quantification in routine clinical practice (e.g., assessment of bone metabolism). When combining quantitative analysis and diagnostic imaging, we recommend using two different reconstruction protocols with task-specific optimized setups (quantitative vs. qualitative reconstruction). Furthermore, individual scatter correction significantly improves both quantitative and qualitative results.

scholarly journals 2D In-Plane Sensitive Hall-Effect Sensor

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 711
Author(s):  
Siya Lozanova ◽  
Ivan Kolev ◽  
Avgust Ivanov ◽  
Chavdar Roumenin
Keyword(s):  
Hall Effect ◽  
Signal To Noise Ratio ◽  
Hall Effect Sensor ◽  
Orthogonal Components ◽  
The Mean ◽  
The Cross ◽  
The Magnetic Field ◽  
Outer Contact ◽  
Hall Elements ◽  
Ic Technology

A new 2D (two-dimensional) in-plane sensitive Hall-effect sensor comprising two identical n-Si Greek-crosses is presented. Each of the crosses contains one central square contact and, symmetrically to each of their four sides, an outer contact is available. Outer electrode from one configuration is connected with the respective opposite contact from the other configuration, thus forming four parallel three-contact (3C) Hall elements. These original connections provide pairs of opposite supply currents in each of the cross-Hall structure. Also the obligatory load resistors in the outer contacts of 3С Hall elements are replaced by internal resistances of crosses themselves. The samples have been implemented by IC technology, using four masks. The magnetic field is parallel to the structures’ plane. The couples of opposite contacts of each Greek-cross are the outputs for the two orthogonal components of the magnetic vector at sensitivities S ≈ 115 V/AT whereas the cross-talk is very promising, reaching no more than 2.4%. The mean lowest detected magnetic induction B at a supply current Is = 3 mA over the frequency range f ≤ 500 Hz at a signal to noise ratio equal to unity, is Bmin ≈ 14 μT.

Multilag Correlation Estimators for Polarimetric Radar Measurements in the Presence of Noise

2012 ◽  
Vol 29 (6) ◽  
pp. 772-795 ◽  
Author(s):  
Lei Lei ◽  
Guifu Zhang ◽  
Richard J. Doviak ◽  
Robert Palmer ◽  
Boon Leng Cheong ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Data Quality ◽  
Signal To Noise Ratio ◽  
Simulated Data ◽  
Radar Data ◽  
Polarimetric Radar ◽  
Signal To Noise ◽  
Spectral Moments ◽  
Radar Measurements

Abstract The quality of polarimetric radar data degrades as the signal-to-noise ratio (SNR) decreases. This substantially limits the usage of collected polarimetric radar data to high SNR regions. To improve data quality at low SNRs, multilag correlation estimators are introduced. The performance of the multilag estimators for spectral moments and polarimetric parameters is examined through a theoretical analysis and by the use of simulated data. The biases and standard deviations of the estimates are calculated and compared with those estimates obtained using the conventional method.

scholarly journals Adaptive Noise Cancellation of an Analog Fiber Optic Link

2021 ◽  
Author(s):  
Mohammad Nazrul Islam
Keyword(s):  
Optical Fiber ◽  
Fiber Optic ◽  
Signal To Noise Ratio ◽  
Optical Power ◽  
Noise Cancellation ◽  
Adaptive Noise Cancellation ◽  
Fiber Link ◽  
The Mean ◽  
Simulation Results ◽  
Adaptive Noise

There are three dominant noise mechanisms in an analog optical fiber link. These are shot noise that is proportional to the mean optical power, relative intensity noise (RIN) that is proportional to the square of the instanteaneous optical power. This report describes an adaptive noise cancellation of these dominant noise processes that persist an analog optical fiber link. The performance of an analog optical fiber link is analyzed by taking the effects of these noise processes. Analytical and simulation results show that some improvement in signal to noise ratio (SNR) and this filter is effective to remove noise adaptively from the optical fiber link.

scholarly journals An enhanced correlation identification algorithm and its application on spread spectrum induced polarization data

2021 ◽  
Vol 28 (2) ◽  
pp. 247-256
Author(s):  
Siming He ◽  
Jian Guan ◽  
Xiu Ji ◽  
Hang Xu ◽  
Yi Wang
Keyword(s):  
Data Processing ◽  
Spread Spectrum ◽  
Background Noise ◽  
Signal To Noise Ratio ◽  
Induced Polarization ◽  
High Resistivity ◽  
Observation System ◽  
Pseudorandom Sequence ◽  
Identification Algorithm ◽  
The Time Domain

Abstract. In spread spectrum induced polarization (SSIP) data processing, attenuation of background noise from the observed data is the essential step that improves the signal-to-noise ratio (SNR) of SSIP data. The time-domain spectral induced polarization based on pseudorandom sequence (TSIP) algorithm has been proposed to improve the SNR of these data. However, signal processing in background noise is still a challenging problem. We propose an enhanced correlation identification (ECI) algorithm to attenuate the background noise. In this algorithm, the cross-correlation matching method is helpful for the extraction of useful components of the raw SSIP data and suppression of background noise. Then the frequency-domain IP (FDIP) method is used for extracting the frequency response of the observation system. Experiments on both synthetic and real SSIP data show that the ECI algorithm will not only suppress the background noise but also better preserve the valid information of the raw SSIP data to display the actual location and shape of adjacent high-resistivity anomalies, which can improve subsequent steps in SSIP data processing and imaging.

scholarly journals Development of the Persian version of high-frequency emphasis quick speech in noise

2019 ◽  
Author(s):  
Jamileh Fatahi ◽  
Maryam Amiri Jahromi ◽  
Fahimeh Hajiabolhassan ◽  
Amirsalar Jafarpisheh ◽  
Nariman Rahbar ◽  
...  
Keyword(s):  
High Frequency ◽  
Signal To Noise Ratio ◽  
Mean Value ◽  
Small Sample ◽  
Test Reliability ◽  
Face Validity ◽  
Mean Values ◽  
Speech In Noise ◽  
Persian Version ◽  
The Mean

Background and Aim: The quick speech in noise (Q-SIN) test shows the difficulty of spee­ch perception in noise by specifying signal to noise ratio (SNR) loss. Although the Persian version of Q-SIN has been already constructed, the high-frequency emphasis version of this test is not available. The present study aimed to construct six lists with high-frequency emphasis and implement it. Methods: We are going to prepare a high-frequ­ency emphasis version of Q-SIN and then test it on a small sample. First, researchers designed the relevant sentences; then experts examined their content and face validity. According to the criteria for developing the Q-SIN test, six lists with high-frequency emphasis were prepared. The test was examined on 26 (13 male and 13 female), 18−35 years old individuals with nor­mal hearing. To determine the test reliability, it was re-administered three weeks later with the same conditions. Results: Of 76 sentences prepared, 36 sentences received enough credit after determination of their content and face validity. These 36 senten­ces were used to make 6 lists. The mean value of SNR50 in the Persian language was obtained -4 dB. The mean values of SNR loss in 6 lists were -1.65, -1.8, -2.23, -1.61, -2.38 and -2.07. The results showed equivalency of lists 1, 2, 3, 4, and 6. Examination of test-retest reliability indicated that all lists except the list 2were reliable. Conclusion: The lists of 1, 3, 4, and 6 are reli­able and equivalent and can be used in clinical application.

An initial assessment of bed destabilization risk past vegetation patches using instrumented particles

2021 ◽  
Author(s):  
Yi Xu ◽  
Valyrakis Manousos ◽  
Panagiotis Michalis
Keyword(s):  
Initial Assessment ◽  
Flow Structures ◽  
Clear Water ◽  
Flow Conditions ◽  
Flow Parameters ◽  
Water Conditions ◽  
The Mean ◽  
Acoustic Doppler Velocimetry ◽  
Patch Density ◽  
Vegetation Patches

&lt;p&gt;Instream vegetation may alter the mean and turbukent flow fields leading to destabilizing riverbed surface, under certain flow conditions. In particular, recent research on instream vegetation hydrodynamics and ecohydrogeomorphology has focused on how energetic flow structures and bulk flow parameters downstream a vegetation may result in riverbed destabilization. This study, demonstrated the application of a 20mm novel instrumented particle in recording entrainment rates downstream simulated vegetation patches of distinct densities, at various distances downstream these. A patch of 6mm acrilic cylinders is used to simulate the emergent vegetation having the same diameter (12cm) and different porosities or densities (void volume equal to 1.25%, 3.15%, 6.25%, 11.25%, and 17.25%). The flow velocity near the instrumented particle is recorded using acoustic Doppler velocimetry (ADV) with appropriate seeding, under clear water conditions. Preliminary results are presented with focus on the effect of vegetation patch density on the flow field and subsequent effects on particle entrainment rates and implications for bed surface destabilisation.&lt;/p&gt;

Diversion from Custody. I: Psychiatric Assessment at the Magistrates' Court

1993 ◽  
Vol 162 (3) ◽  
pp. 325-330 ◽  
Author(s):  
Philip L. A. Joseph ◽  
Mark Potter
Keyword(s):  
Psychiatric Disorder ◽  
Hospital Admission ◽  
Patient Treatment ◽  
Initial Assessment ◽  
Psychiatric Assessment ◽  
Mentally Disordered ◽  
The Mean

The homeless mentally disordered defendant facing minor charges poses considerable problems regarding appropriate disposal. Psychiatric assessment may be required in order to facilitate the court's decision, but this is often available only after remand in custody. A psychiatric assessment service based at two inner-London magistrates' courts is described. Over 18 months, 201 defendants were referred. They were predominantly male, single, and of no fixed abode, suffering from serious psychiatric disorder; these defendants had often received previous in-patient treatment, frequently as detained patients. They typically were recidivists charged with minor offences. Following initial assessment, 25% were admitted to hospital, 50% were released, and 25% returned to custody. The Crown Prosecution Service discontinued 29% of cases. For those admitted directly to hospital, the mean (s.d.) time from arrest to hospital admission was 5.8 (6.8) days, significantly quicker than with prison-based assessments.

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