Surface dielectric function of CdTe(110) obtained by polarized surface differential reflectivity data

1995 ◽  
Vol 13 (4) ◽  
pp. 1913-1916 ◽  
Author(s):  
A. Cricenti ◽  
A. C. Felici
Keyword(s):  
Dielectric Function ◽  
Polarized Surface ◽  
Reflectivity Data ◽  
Differential Reflectivity

Dielectric functions of Si(111)2×1, Ge(111)2×1, GaAs(110) and GaP(110) surfaces obtained by polarized surface differential reflectivity

1987 ◽  
Vol 189-190 ◽  
pp. A453
Author(s):  
S. Selci ◽  
A. Cricenti ◽  
F. Ciccacci ◽  
A.C. Felici ◽  
C. Goletti ◽  
...  
Keyword(s):  
Polarized Surface ◽  
Differential Reflectivity

Polarized surface differential reflectivity and oxygen chemisorption on InP(110) surfaces

1991 ◽  
Vol 251-252 ◽  
pp. 281-285 ◽  
Author(s):  
A. Cricenti ◽  
S. Selci ◽  
A.C. Felici ◽  
L. Ferrari ◽  
A. Gavrilovich ◽  
...  
Keyword(s):  
Oxygen Chemisorption ◽  
Polarized Surface ◽  
Differential Reflectivity

scholarly journals Improved analysis of solar signals for differential reflectivity monitoring

2016 ◽  
Author(s):  
Asko Huuskonen ◽  
Mikko Kurri ◽  
Iwan Holleman
Keyword(s):  
Vertical Polarization ◽  
Daily Monitoring ◽  
Weather Radars ◽  
Radar Network ◽  
Angle Data ◽  
Data Points ◽  
Reflectivity Data ◽  
Differential Reflectivity ◽  
Better Than ◽  
Receiver Bias

Abstract. The method for the daily monitoring of the differential reflectivity bias for polarimetric weather radars is developed. Improved quality control is applied to the solar signals detected during the operational scanning of the radar which removes efficiently rain and clutter contamination occurring in the solar hits. The simultaneous reflectivity data are used as a proxy to determine which data points are to be removed. A number of analysis methods are compared, and methods based on surface fitting are found superior to simple averaging. A separate fit to the reflectivity of the horizontal and vertical polarization channels is recommended, because it provides in addition to the differential reflectivity the pointing difference of the polarization channels, the squint angle. Data from the Finnish weather radar network shows that the squint angles are less than 0.02° and that the differential reflectivity bias is stable and determined to better than 0.04 dB. The results are compared to those from measurements at vertical incidence, which allows to determine the differential receiver bias and the transmitter bias.

Modeling and Interpretation of S-Band Ice Crystal Depolarization Signatures from Data Obtained by Simultaneously Transmitting Horizontally and Vertically Polarized Fields

2014 ◽  
Vol 53 (6) ◽  
pp. 1659-1677 ◽  
Author(s):  
J. C. Hubbert ◽  
S. M. Ellis ◽  
W.-Y. Chang ◽  
S. Rutledge ◽  
M. Dixon
Keyword(s):  
Electric Fields ◽  
Ice Crystals ◽  
Polarization Data ◽  
Convective Storms ◽  
Vertically Aligned ◽  
Linear Depolarization Ratio ◽  
Reflectivity Data ◽  
Convective Cells ◽  
Differential Reflectivity ◽  
Ice Phase

AbstractData collected by the National Center for Atmospheric Research S-band polarimetric radar (S-Pol) during the Terrain-Influenced Monsoon Rainfall Experiment (TiMREX) in Taiwan are analyzed and used to infer storm microphysics in the ice phase of convective storms. Both simultaneous horizontal (H) and vertical (V) (SHV) transmit polarization data and fast-alternating H and V (FHV) transmit polarization data are used in the analysis. The SHV Zdr (differential reflectivity) data show radial stripes of biased data in the ice phase that are likely caused by aligned and canted ice crystals. Similar radial streaks in the linear depolarization ratio (LDR) are presented that are also biased by the same mechanism. Dual-Doppler synthesis and sounding data characterize the storm environment and support the inferences concerning the ice particle types. Small convective cells were observed to have both large positive and large negative Kdp (specific differential phase) values. Negative Kdp regions suggest that ice crystals are vertically aligned by electric fields. Since high |Kdp| values of 0.8° km−1 in both negative and positive Kdp regions in the ice phase are accompanied by Zdr values close to 0 dB, it is inferred that there are two types of ice crystals present: 1) smaller aligned ice crystals that cause the Kdp signatures and 2) larger aggregates or graupel that cause the Zdr signatures. The inferences are supported with simulated ice particle scattering calculations. A radar scattering model is used to explain the anomalous radial streaks in SHV and LDR.

The Utility of X-Band Polarimetric Radar for Quantitative Estimates of Rainfall Parameters

2005 ◽  
Vol 6 (3) ◽  
pp. 248-262 ◽  
Author(s):  
Sergey Y. Matrosov ◽  
David E. Kingsmill ◽  
Brooks E. Martner ◽  
F. Martin Ralph
Keyword(s):  
Rain Attenuation ◽  
Polarimetric Radar ◽  
Differential Phase Shift ◽  
Differential Phase ◽  
X Band ◽  
Drop Size Distributions ◽  
Russian River ◽  
Phase Shift Data ◽  
Reflectivity Data ◽  
Differential Reflectivity

Abstract The utility of X-band polarimetric radar for quantitative retrievals of rainfall parameters is analyzed using observations collected along the U.S. west coast near the mouth of the Russian River during the Hydrometeorological Testbed project conducted by NOAA’s Environmental Technology and National Severe Storms Laboratories in December 2003 through March 2004. It is demonstrated that the rain attenuation effects in measurements of reflectivity (Ze) and differential attenuation effects in measurements of differential reflectivity (ZDR) can be efficiently corrected in near–real time using differential phase shift data. A scheme for correcting gaseous attenuation effects that are important at longer ranges is introduced. The use of polarimetric rainfall estimators that utilize specific differential phase and differential reflectivity data often provides results that are superior to estimators that use fixed reflectivity-based relations, even if these relations were derived from the ensemble of drop size distributions collected in a given geographical region. Comparisons of polarimetrically derived rainfall accumulations with data from the high-resolution rain gauges located along the coast indicated deviation between radar and gauge estimates of about 25%. The ZDR measurements corrected for differential attenuation were also used to retrieve median raindrop sizes, D0. Because of uncertainties in differential reflectivity measurements, these retrievals are typically performed only for D0 > 0.75 mm. The D0 estimates from an impact disdrometer located at 25 km from the radar were in good agreement with the radar retrievals. The experience of operating the transportable polarimetric X-band radar in the coastal area that does not have good coverage by the National Weather Service radar network showed the value of such radar in filling the gaps in the network coverage. The NOAA X-band radar was effective in covering an area up to 40–50 km in radius offshore adjacent to a region that is prone to flooding during wintertime landfalling Pacific storms.

Polarized surface differential reflectivity and oxygen chemisorption on InP(110) surfaces

1991 ◽  
Vol 251-252 ◽  
pp. A325
Author(s):  
A. Cricenti ◽  
S. Selci ◽  
A.C. Felici ◽  
L. Ferrari ◽  
A. Gavrilovich ◽  
...  
Keyword(s):  
Oxygen Chemisorption ◽  
Polarized Surface ◽  
Differential Reflectivity

A Polarimetric Radar Analysis of Ice Microphysical Processes in Melting Layers of Winter Storms Using S-Band Quasi-Vertical Profiles

2020 ◽  
Vol 59 (4) ◽  
pp. 751-767 ◽  
Author(s):  
Erica M. Griffin ◽  
Terry J. Schuur ◽  
Alexander V. Ryzhkov
Keyword(s):  
Cold Season ◽  
Vertical Profiles ◽  
Horizontal Polarization ◽  
Winter Storms ◽  
Differential Phase ◽  
High Vertical Resolution ◽  
Microphysical Processes ◽  
Statistical Relationships ◽  
Reflectivity Data ◽  
Differential Reflectivity

AbstractQuasi-vertical profiles (QVPs) obtained from a database of U.S. WSR-88D data are used to document polarimetric characteristics of the melting layer (ML) in cold-season storms with high vertical resolution and accuracy. A polarimetric technique to define the top and bottom of the ML is first introduced. Using the QVPs, statistical relationships are developed to gain insight into the evolution of microphysical processes above, within, and below the ML, leading to a statistical polarimetric model of the ML that reveals characteristics that reflectivity data alone are not able to provide, particularly in regions of weak reflectivity factor at horizontal polarization ZH. QVP ML statistics are examined for two regimes in the ML data: ZH ≥ 20 dBZ and ZH < 20 dBZ. Regions of ZH ≥ 20 dBZ indicate locations of MLs collocated with enhanced differential reflectivity ZDR and reduced copolar correlation coefficient ρhv, while for ZH < 20 dBZ a well-defined ML is difficult to discern using ZH alone. Evidence of large ZDR up to 4 dB, backscatter differential phase δ up to 8°, and low ρhv down to 0.80 associated with lower ZH (from −10 to 20 dBZ) in the ML is observed when pristine, nonaggregated ice falls through it. Positive correlation is documented between maximum specific differential phase KDP and maximum ZH in the ML; these are the first QVP observations of KDP in MLs documented at S band. Negative correlation occurs between minimum ρhv in the ML and ML depth and between minimum ρhv in the ML and the corresponding enhancement of ZH (ΔZH = ZHmax − ZHrain).

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