scholarly journals Deployment and Performance of an X-Band Dual-Polarization Radar during the Southern China Monsoon Rainfall Experiment

Atmosphere ◽  
2017 ◽  
Vol 9 (1) ◽  
pp. 4 ◽  
Author(s):  
Zhao Shi ◽  
Haonan Chen ◽  
Venkatachalam Chandrasekar ◽  
Jianxin He
Keyword(s):  
Monsoon Rainfall ◽  
Southern China ◽  
Dual Polarization ◽  
X Band ◽  
And Performance

Monitoring wildfire using high-resolution compact X-band dual-polarization radar: A case study in southern China

2019 ◽  
Vol 225 ◽  
pp. 165-171
Author(s):  
Zhaoming Li ◽  
Haonan Chen ◽  
Hongxing Chu ◽  
V. Chandrasekar ◽  
Hongbin Chen ◽  
...  
Keyword(s):  
High Resolution ◽  
Southern China ◽  
Dual Polarization ◽  
X Band

Case Dependence of Multiscale Interactions between Multisource Perturbations for Convection-Permitting Ensemble Forecasting during SCMREX

2021 ◽  
Author(s):  
Xubin Zhang
Keyword(s):  
Perturbation Methods ◽  
Monsoon Rainfall ◽  
Southern China ◽  
Ensemble Forecasting ◽  
Ensemble Prediction ◽  
Synoptic Scale ◽  
Ensemble Prediction System ◽  
Control Member ◽  
Probabilistic Forecasts ◽  
Perturbation Energy

AbstractThis study examines the case dependence of the multiscale characteristics of initial condition (IC) and model physics (MO) perturbations and their interactions in a convection-permitting ensemble prediction system (CPEPS), focusing on the 12-h forecasts of precipitation perturbation energy. The case dependence of forecast performances of various ensemble configurations is also examined to gain guidance for CPEPS design. Heavy-rainfall cases over Southern China during the Southern China Monsoon Rainfall Experiment (SCMREX) in May 2014 were discriminated between the strongly and weakly forced events in terms of synoptic-scale forcing, each of which included 10 cases. In the cases with weaker forcing, MO perturbations showed larger influences while the enhancements of convective activities relative to the control member due to IC perturbations were less evident, leading to smaller dispersion reduction due to adding MO perturbations to IC perturbations. Such dispersion reduction was more sensitive to IC and MO perturbation methods in the weakly and strongly forced cases, respectively. The dispersion reduction improved the probabilistic forecasts of precipitation, with more evident improvements in the cases with weaker forcing. To improve the benefits of dispersion reduction in forecasts, it is instructive to elaborately consider the case dependence of dispersion reduction, especially the various sensitivities of dispersion reduction to different-source perturbation methods in various cases, in CPEPS design.

scholarly journals Precipitation Classification and Quantification Using X-Band Dual-Polarization Weather Radar: Application in the Hydrometeorology Testbed

2013 ◽  
Vol 30 (9) ◽  
pp. 2108-2120 ◽  
Author(s):  
S. Lim ◽  
R. Cifelli ◽  
V. Chandrasekar ◽  
S. Y. Matrosov
Keyword(s):  
Quality Control ◽  
Phase Retrieval ◽  
Estimation Method ◽  
Rain Gauge ◽  
Dual Polarization ◽  
Rainfall Estimation ◽  
Differential Phase ◽  
Melting Region ◽  
X Band ◽  
Fuzzy Logic Technique

Abstract This paper presents new methods for rainfall estimation from X-band dual-polarization radar observations along with advanced techniques for quality control, hydrometeor classification, and estimation of specific differential phase. Data collected from the Hydrometeorology Testbed (HMT) in orographic terrain of California are used to demonstrate the methodology. The quality control and hydrometeor classification are specifically developed for X-band applications, which use a “fuzzy logic” technique constructed from the magnitude of the copolar correlation coefficient and the texture of differential propagation phase. In addition, an improved specific differential phase retrieval and rainfall estimation method are also applied. The specific differential phase estimation is done for both the melting region and rain region, where it uses a conventional filtering method for the melting region and a self-consistency-based method that distributes the total differential phase consistent with the reflectivity factor for the rain region. Based on the specific differential phase, rainfall estimations were computed using data obtained from the NOAA polarimetric X-band radar for hydrometeorology (HYDROX) and evaluated using HMT rain gauge observations. The results show that the methodology works well at capturing the high-frequency rainfall variations for the events analyzed herein and can be useful for mountainous terrain applications.

Design and performance of a microstrip reflectarray on a uniaxial substrate

2002 ◽  
Vol 80 (1) ◽  
pp. 7-17 ◽  
Author(s):  
A Iliadis ◽  
K Siakavara
Keyword(s):  
Electromagnetic Field ◽  
Green's Function ◽  
Method Of Moments ◽  
Dielectric Substrate ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Dual Polarization ◽  
Full Wave ◽  
Wave Technique ◽  
And Performance

A design formulation of microstrip reflectarrays is presented in this paper. Previous published articles, referring to this subject, present results for reflectarrays on a uniform dielectric substrate. In this work microstrip reflectarrays with offset feed, dual polarization, and side-lobe level under control, fabricated on a uniaxial substrate were studied. The method of moments, combined with the full-wave technique, and the corresponding dyadic Green's function is used for the specification of the electromagnetic field scattered by the array. PACS No.: 84.40B

scholarly journals Integrated Correction Algorithm for X Band Dual-Polarization Radar Reflectivity Based on CINRAD/SA Radar

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 119
Author(s):  
Chao Wang ◽  
Chong Wu ◽  
Liping Liu ◽  
Xi Liu ◽  
Chao Chen
Keyword(s):  
Attenuation Correction ◽  
Fixed Ratio ◽  
Water Layer ◽  
Resonance Scattering ◽  
Rain Attenuation ◽  
Correction Algorithm ◽  
Dual Polarization ◽  
Differential Phase ◽  
X Band ◽  
Ratio Correction

The values of ratio a of the linear relationship between specific attenuation and specific differential phase vary significantly in convective storms as a result of resonance scattering. The best-linear-fit ratio a at X band is determined using the modified attenuation correction algorithm based on differential phase and attenuation, as well as the premise that reflectivity is unattenuated in S band radar detection. Meanwhile, the systemic reflectivity bias between the X band radar and S band radar and water layer attenuation (ZW) on the wet antenna cover of the X band radar are also considered. The good performance of the modified correction algorithm is demonstrated in a moderate rainfall event. The data were collected by four X band dual-polarization (X-POL) radar sites, namely, BJXCP, BJXFS, BJXSY, and BJXTZ, and a China’s New Generation Weather Radar (CINRAD/SA radar) site, BJSDX, in Beijing on 20 July 2016. Ratio a is calculated for each volume scan of the X band radar, with a mean value of 0.26 dB deg−1 varying from 0.20 to 0.31 dB deg−1. The average values of systemic reflectivity bias between the X band radar (at BJXCP, BJXFS, BJXSY, and BJXTZ) and S band radar (at BJSDX) are 0, −3, 2, and 0 dB, respectively. The experimentally determined ZW is in substantial agreement with the theoretically calculated ones, and their values are an order of magnitude smaller than rain attenuation. The comparison of the modified attenuation correction algorithm and the empirical-fixed-ratio correction algorithm is further evaluated at the X-POL radar. It is shown that the modified attenuation correction algorithm in the present paper provides higher correction accuracy for rain attenuation than the empirical-fixed-ratio correction algorithm.

scholarly journals Vegetated Target Decorrelation in SAR and Interferometry: Models, Simulation, and Performance Evaluation

2020 ◽  
Vol 12 (16) ◽  
pp. 2545 ◽  
Author(s):  
Andrea Monti-Guarnieri ◽  
Marco Manzoni ◽  
Davide Giudici ◽  
Andrea Recchia ◽  
Stefano Tebaldini
Keyword(s):  
Formal Method ◽  
Temporal Stability ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Short Term ◽  
Realistic Case ◽  
X Band ◽  
Temporal Decorrelation ◽  
And Performance

The paper addresses the temporal stability of distributed targets, particularly referring to vegetation, to evaluate the degradation affecting synthetic aperture radar (SAR) imaging and repeat-pass interferometry, and provide efficient SAR simulation schemes for generating big dataset from wide areas. The models that are mostly adopted in literature are critically reviewed, and aim to study decorrelation in a range of time (from hours to days), of interest for long-term SAR, such as ground-based or geosynchronous, or repeat-pass SAR interferometry. It is shown that none of them explicitly account for a decorrelation occurring in the short-term. An explanation is provided, and a novel temporal decorrelation model is proposed to account for that fast decorrelation. A formal method is developed to evaluate the performance of SAR focusing, and interferometry on a homogenous, stationary scene, in terms of Signal-to-Clutter Ratio (SCR), and interferometric coherence. Finally, an efficient implementation of an SAR simulator capable of handling the realistic case of heterogeneous decorrelation over a wide area is discussed. Examples are given by assuming two geostationary SAR missions in C and X band.

Optimum Estimation of Rain Microphysical Parameters From X-Band Dual-Polarization Radar Observables

2013 ◽  
Vol 51 (5) ◽  
pp. 3063-3076 ◽  
Author(s):  
John Kalogiros ◽  
Marios N. Anagnostou ◽  
Emmanouil N. Anagnostou ◽  
Mario Montopoli ◽  
Errico Picciotti ◽  
...  
Keyword(s):  
Dual Polarization ◽  
Optimum Estimation ◽  
Microphysical Parameters ◽  
X Band

Design and performance of an electrostatically focused 5-kw X-band traveling-wave tube

1964 ◽  
Vol 11 (3) ◽  
pp. 102-114 ◽  
Author(s):  
E.F. Belohoubek ◽  
W.W. Siekanowicz ◽  
F.E. Vaccaro
Keyword(s):  
Traveling Wave ◽  
Traveling Wave Tube ◽  
Wave Tube ◽  
X Band ◽  
And Performance
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