Calibration Issues of Dual-Polarization Radar Measurements

2005 ◽  
Vol 22 (8) ◽  
pp. 1138-1155 ◽  
Author(s):  
Alexander V. Ryzhkov ◽  
Scott E. Giangrande ◽  
Valery M. Melnikov ◽  
Terry J. Schuur
Keyword(s):  
High Elevation ◽  
Absolute Calibration ◽  
Dual Polarization ◽  
Light Rain ◽  
Weather Radars ◽  
Mechanical Constraints ◽  
Wide Range ◽  
Temporal Averaging ◽  
The Impact ◽  
Self Consistency

Abstract Techniques for the absolute calibration of radar reflectivity Z and differential reflectivity ZDR measured with dual-polarization weather radars are examined herein. Calibration of Z is based on the idea of self-consistency among Z, ZDR, and the specific differential phase KDP in rain. Extensive spatial and temporal averaging is used to derive the average values of ZDR and KDP for each 1 dB step in Z. Such averaging substantially reduces the standard error of the KDP estimate so the technique can be used for a wide range of rain intensities, including light rain. In this paper, the performance of different consistency relations is analyzed and a new self-consistency methodology is suggested. The proposed scheme substantially reduces the impact of variability in the drop size distribution and raindrop shape on the quality of the Z calibration. The new calibration technique was tested on a large polarimetric dataset obtained during the Joint Polarization Experiment in Oklahoma and yielded an accuracy of Z calibration within 1 dB. Absolute calibration of ZDR is performed using solar measurements at orthogonal polarizations and polarimetric properties of natural targets like light rain and dry aggregated snow that are probed at high elevation angles. Because vertical sounding is prohibited for operational Weather Surveillance Radar-1988 Doppler (WSR-88D) radars because of mechanical constraints, the existing methodology for ZDR calibration is modified for nonzenith elevation angles. It is shown that the required 0.1–0.2-dB accuracy of the ZDR calibration is potentially achievable.

Calibration of Dual-Polarization Radar in the Presence of Partial Beam Blockage

2005 ◽  
Vol 22 (8) ◽  
pp. 1156-1166 ◽  
Author(s):  
Scott E. Giangrande ◽  
Alexander V. Ryzhkov
Keyword(s):  
Dual Polarization ◽  
Calibration Technique ◽  
Light Rain ◽  
Weather Radars ◽  
Time Integral ◽  
Suggested Technique ◽  
Radar Measurements ◽  
Differential Reflectivity ◽  
Self Consistency ◽  
Azimuthal Modulation

Abstract In the presence of partial beam blockage (PBB), weather radar measurements can experience significant bias that directly compromises the accuracy of the hydrologic applications. Techniques for the calibration of the radar reflectivity factor Z and differential reflectivity ZDR, measured with dual-polarization weather radars in the presence of partial beam obstruction, are examined in this paper. The proposed ZDR calibration technique utilizes radar measurements of ZDR in light rain and dry aggregated snow at unblocked and blocked elevations. This calibration technique was tested for the National Severe Storms Laboratory’s (NSSL’s) Cimarron radar that suffers from PBB, and a polarimetric prototype of the Weather Surveillance Radar-1988 Doppler (WSR-88D) that does not experience PBB. Results indicate that the ZDR bias that is associated with PBB can be calibrated with an accuracy of 0.2–0.3 dB, provided that the dataset is sufficiently large. Calibration of Z in the presence of PBB is based on the idea of self-consistency among Z, ZDR, and the specific differential phase KDP in rain. The self-consistency calibration of Z from the Cimarron radar is performed following an area–time integral method. Integration is partitioned into small azimuthal sectors to assess the azimuthal modulation of the Z bias. The suggested technique is validated by direct comparisons of reflectivity factors that are measured by the Cimarron radar and the unobstructed operational WSR-88D radar. It is shown that the azimuthal modulation of Z that is caused by PBB is well captured, and the accuracy of the Z calibration is within 2–3 dB.

scholarly journals The Influence of Antenna Radome on Weather Radar Calibration and Its Real-Time Assessment

2013 ◽  
Vol 30 (4) ◽  
pp. 676-689 ◽  
Author(s):  
E. Gorgucci ◽  
R. Bechini ◽  
L. Baldini ◽  
R. Cremonini ◽  
V. Chandrasekar
Keyword(s):  
Real Time ◽  
The Self ◽  
Absolute Calibration ◽  
Reference Source ◽  
Clear Understanding ◽  
Qualitative Comparison ◽  
Mean Values ◽  
Radar Calibration ◽  
The Impact ◽  
Self Consistency

Abstract Operational weather radars are usually equipped with a radome to reduce the wind load on the antenna and to allow continuous operation under bad weather conditions. The study is focused on quantifying the impact on radar polarimetric measurements due to the presence of a radome. Analysis refers to the transportable X-band polarimetric radar of the Agenzia Regionale per la Protezione Ambientale (ARPA) Piemonte (ARX), which uses a “bullet shaped” radome to provide environmental protection to the antenna and receiver apparatus system. Radar calibration is performed using wet and dry radomes. Differential reflectivity calibration results are compared with those obtained using the sun as a radiation reference source. Estimates have comparable mean values, with their differences being within the standard deviation. The paper describes a method based on the self-consistency principle that takes into account the loss induced by radome wetting due to rain to adjust the absolute calibration of the radar in real time. To verify how well this method overcomes the problem of excess attenuation caused by the presence of precipitation on the radome, two validation methods are presented. The first uses an empirical model to estimate the two-way wet radome losses for a qualitative comparison, with the corresponding losses obtained by the self-consistency principle. The second employs comparisons between radar and gauge rainfall accumulations with and without radome correction. This approach offers a clear understanding of the response of the correction, providing quantitative performance in a real case.

scholarly journals Hydroclimatological Patterns and Limnological Characteristics of Unique Wetland Systems on the Argentine High Andean Plateau

Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 164
Author(s):  
Diego Frau ◽  
Brendan J. Moran ◽  
Felicity Arengo ◽  
Patricia Marconi ◽  
Yamila Battauz ◽  
...  
Keyword(s):  
Soluble Reactive Phosphorus ◽  
High Sensitivity ◽  
High Elevation ◽  
Climatic Conditions ◽  
The Body ◽  
Nutrient Concentrations ◽  
Wide Range ◽  
Human Perturbations ◽  
Baseline Information ◽  
The Impact

High-elevation wetlands in South America are not well described despite their high sensitivity to human impact and unique biodiversity. We describe the hydroclimatological and limnological characteristics of 21 wetlands on the High Andean Plateau of Argentina, synthesizing information gathered over ten years (2010–2020). We collected physical-chemical, phytoplankton, and zooplankton data and counted flamingos in each wetland. We also conducted an extensive analysis of climatic patterns and hydrological responses since 1985. These wetlands are shallow, with a wide range of salinity (from fresh to brine), mostly alkaline, and are dominated by carbonate and gypsum deposits and sodium-chloride waters. They tend to have high nutrient concentrations. Plankton shows a low species richness and moderate to high dominance of taxa. Flamingos are highly dependent on the presence of Bacillariophyta, which appears to be positively linked to silica and soluble reactive phosphorus availability. Climatic conditions show a strong region-wide increase in average air temperature since the mid-1980s and a decrease in precipitation between 1985–1999 and 2000–2020. These high-elevation wetlands are fundamentally sensitive systems; therefore, having baseline information becomes imperative to understanding the impact of climatic changes and other human perturbations. This work attempts to advance the body of scientific knowledge of these unique wetland systems.

THE IMPACT OF LEADERSHIP PRACTICES TO TEAM MEMBERS’ SATISFACTION

2009 ◽  
Vol 8 (1) ◽  
Author(s):  
Chalimah .
Keyword(s):  
Conflict Resolution ◽  
Leadership Practices ◽  
Hotel Industry ◽  
Leader Behavior ◽  
Team Leader ◽  
Shop Floor ◽  
Team Members ◽  
Top Executives ◽  
Wide Range ◽  
The Impact

eamwork is becoming increasingly important to wide range of operations. It applies to all levels of the company. It is just as important for top executives as it is to middle management, supervisors and shop floor workers. Poor teamwork at any level or between levels can seriously damage organizational effectiveness. The focus of this paper was therefore to examine whether leadership practices consist of team leader behavior, conflict resolution style and openness in communication significantly influenced the team member’s satisfaction in hotel industry. Result indicates that team leader behavior and the conflict resolution style significantly influenced team member satisfaction. It was surprising that openness in communication did not affect significantly to the team members’ satisfaction.

Stress, anxiety, depression and burnout in frontline health care workers during COVID-19 pandemic: a brief systematic review and new data from Russia

2021 ◽  
Author(s):  
Ekaterina Mosolova ◽  
Dmitry Sosin ◽  
Sergey Mosolov
Keyword(s):  
Risk Factors ◽  
Systematic Review ◽  
Female Gender ◽  
Assessment Tools ◽  
Care Workers ◽  
Younger Age ◽  
Wide Range ◽  
Associated Risk Factors ◽  
Anxiety Depression ◽  
The Impact

During the COVID-19 pandemic, healthcare workers (HCWs) have been subject to increased workload while also exposed to many psychosocial stressors. In a systematic review we analyze the impact that the pandemic has had on HCWs mental state and associated risk factors. Most studies reported high levels of depression and anxiety among HCWs worldwide, however, due to a wide range of assessment tools, cut-off scores, and number of frontline participants in the studies, results were difficult to compare. Our study is based on two online surveys of 2195 HCWs from different regions of Russia during spring and autumn epidemic outbreaks revealed the rates of anxiety, stress, depression, emotional exhaustion and depersonalization and perceived stress as 32.3%, 31.1%, 45.5%, 74.2%, 37.7% ,67.8%, respectively. Moreover, 2.4% of HCWs reported suicidal thoughts. The most common risk factors include: female gender, nurse as an occupation, younger age, working for over 6 months, chronic diseases, smoking, high working demands, lack of personal protective equipment, low salary, lack of social support, isolation from families, the fear of relatives getting infected. These results demonstrate the need for urgent supportive programs for HCWs fighting COVID-19 that fall into higher risk factors groups.

A MODELING SYSTEM FOR CLIMATE CHANGE RISK ASSESSMENT, MANAGEMENT AND HEDGING IN COASTAL AREAS

2017 ◽  
Author(s):  
Sergei Soldatenko ◽  
Sergei Soldatenko ◽  
Genrikh Alekseev ◽  
Genrikh Alekseev ◽  
Alexander Danilov ◽  
...  
Keyword(s):  
Climate Change ◽  
Risk Assessment ◽  
Coastal Areas ◽  
Mitigation Strategies ◽  
System Structure ◽  
The Arctic ◽  
Risk Modeling ◽  
Wide Range ◽  
Adverse Weather ◽  
The Impact

Every aspect of human operations faces a wide range of risks, some of which can cause serious consequences. By the start of 21st century, mankind has recognized a new class of risks posed by climate change. It is obvious, that the global climate is changing, and will continue to change, in ways that affect the planning and day to day operations of businesses, government agencies and other organizations and institutions. The manifestations of climate change include but not limited to rising sea levels, increasing temperature, flooding, melting polar sea ice, adverse weather events (e.g. heatwaves, drought, and storms) and a rise in related problems (e.g. health and environmental). Assessing and managing climate risks represent one of the most challenging issues of today and for the future. The purpose of the risk modeling system discussed in this paper is to provide a framework and methodology to quantify risks caused by climate change, to facilitate estimates of the impact of climate change on various spheres of human activities and to compare eventual adaptation and risk mitigation strategies. The system integrates both physical climate system and economic models together with knowledge-based subsystem, which can help support proactive risk management. System structure and its main components are considered. Special attention is paid to climate risk assessment, management and hedging in the Arctic coastal areas.

The Management of Post-Tonsillectomy Morbidity in Patients With Sleep Apnoea

2019 ◽  
Vol 70 (10) ◽  
pp. 3738-3740
Keyword(s):  
Day Surgery ◽  
Sleep Apnoea ◽  
Integrative Approach ◽  
Multicenter Studies ◽  
Therapeutic Modalities ◽  
Advantages And Disadvantages ◽  
Obstructive Sleep ◽  
Wide Range ◽  
The Impact ◽  
Surgery Center

The Tonsillectomy in children or adults is an intervention commonly encountered in the ENT (Ear Nose and Throat) and Head and Neck surgeon practice. The current tendency is to perform this type of surgery in major ambulatory surgery centers. Two objectives are thus pursued: first of all, the increase of the patient quality of life through the reintegration into the family as quickly as possible and secondly, the expenses associated with continuous hospitalization are reduced. Any tertiary (multidisciplinary) sleep center must ensure the complete diagnosis and treatment (including surgery) of sleep respiratory disorders. Under these conditions the selection of patients and especially the implementation of the specific protocols in order to control the postoperative complications it becomes essential. The present paper describes our experience of tonsillectomy as treatment for selected patients with chronic rhonchopathy (snoring) and mild to moderate obstructive sleep apnoea. It was presented the impact of antibiotics protocols in reducing the main morbid outcomes following tonsillectomy, in our day surgery center. The obtained results can also be a prerequisite for the integrative approach of the patients with sleep apnoea who were recommended surgical treatment. Considering the wide range of therapeutic modalities used in sleep apnoea, each with its specific advantages and disadvantages, more extensive and multicenter studies are needed. Keywords: post-tonsillectomy morbidity, day surgery center, sleep disorders

Cognitive Impact of Cerebellar Damage: Is There a Future for Cognitive Rehabilitation?

2018 ◽  
Vol 17 (3) ◽  
pp. 199-206 ◽  
Author(s):  
Kim van Dun ◽  
Frank V. Overwalle ◽  
Mario Manto ◽  
Peter Marien
Keyword(s):  
Affective Disorders ◽  
Cognitive Rehabilitation ◽  
Therapeutic Interventions ◽  
Posterior Fossa Surgery ◽  
Daily Life Activities ◽  
Wide Range ◽  
Affective Deficits ◽  
Cerebellar Injury ◽  
Cognitive Therapies ◽  
The Impact

Background & Objective: During the past 3 decades, numerous neurophysiological, neuroimaging, experimental and clinical studies have evidenced a crucial role for the cerebellum in cognitive, affective and behavioral functions. As a result of the acknowledged modulatory role of the cerebellum upon remote structures such as the cerebral cortex, cerebellar injury may give rise to a constellation of behavioral, affective and cognitive symptoms (Schmahmann's Syndrome). In sharp contrast to the wide range of therapeutic interventions to treat cognitive and affective disorders following cerebral cortical lesions and despite the consequences of Schmahmann’s syndrome upon daily life activities, the literature is surprisingly only scantly documented with studies investigating the impact of cognitive therapies on cerebellar induced cognitive and affective disorders. This survey aims to present an overview of the therapeutic interventions available in the literature as a possible treatment for Schmahmann’s Syndrome after cerebellar injury, after posterior fossa surgery in children, and in children with neurodevelopmental disorders. Although systematical studies are clearly warranted, available evidence suggests that cerebellar-induced cognitive and affective disorders should be treated in a specific way. Approaches where the patients are explicitly made aware of their deficits and are considered to act as an “external cerebellum” are the most promising. Conclusion: The study of the anatomical connectivity of the cerebellar microcomplexes involved in cognitive/affective deficits is likely to play a major-role in the future.

Religion and Medicine

2020 ◽  
Author(s):  
Jeff Levin ◽  
Stephen G. Post
Keyword(s):  
Clinical Decision Making ◽  
Well Being ◽  
Clinical Decision ◽  
Religion And Medicine ◽  
Physical And Mental Health ◽  
Faith Based ◽  
Baylor University ◽  
Wide Range ◽  
History Of ◽  
The Impact

In Religion and Medicine, Dr. Jeff Levin, distinguished Baylor University epidemiologist, outlines the longstanding history of multifaceted interconnections between the institutions of religion and medicine. He traces the history of the encounter between these two institutions from antiquity through to the present day, highlighting a myriad of contemporary alliances between the faith-based and medical sectors. Religion and Medicine tells the story of: religious healers and religiously branded hospitals and healthcare institutions; pastoral professionals involved in medical missions, healthcare chaplaincy, and psychological counseling; congregational health promotion and disease prevention programs and global health initiatives; research studies on the impact of religious and spiritual beliefs and practices on physical and mental health, well-being, and healing; programs and centers for medical research and education within major universities and academic institutions; religiously informed bioethics and clinical decision-making; and faith-based health policy initiatives and advocacy for healthcare reform. Religion and Medicine is the first book to cover the full breadth of this subject. It documents religion-medicine alliances across religious traditions, throughout the world, and over the course of history. It summarizes a wide range of material of relevance to historians, medical professionals, pastors and theologians, bioethicists, scientists, public health educators, and policymakers. The product of decades of rigorous and focused research, Dr. Levin has produced the most comprehensive history of these developments and the finest introduction to this emerging field of scholarship.

Textual Transformations

2019 ◽  
Keyword(s):  
Early Modern ◽  
Financial Incentives ◽  
Book History ◽  
John Dryden ◽  
Book Production ◽  
Original Essays ◽  
Wide Range ◽  
Lucy Hutchinson ◽  
The Many ◽  
The Impact

This collection of twelve original essays by an international team of eminent scholars in the field of book history explores the many ways in which early modern books were subject to reworking, re-presentation, revision and reinterpretation. Their history is often the history of multiple, sometimes competing, agencies as their texts were re-packaged, redirected and transformed in ways that their original authors might hardly recognize. The essays discuss the processes of editing, revision, redaction, selection, abridgement, glossing, disputation, translation and posthumous publication that resulted in a textual elasticity and mobility that could dissolve distinctions between text and paratexts, textuality and intertextuality, manuscript and print, author and reader or editor, such that title and author’s name are no longer sufficient pointers to a book’s identity or contents. The essays are alive to the impact of commercial and technological aspects of book production and distribution (discussing, for example, the career of the pre-eminent bookseller John Nourse, the market appeal of abridgements, and the financial incentives to posthumous publication), but their interest is also in the many additional forms of agency that shaped texts and their meanings as books were repurposed to articulate, and respond to, a variety of cultural and individual needs. They engage with early modern religious, political, philosophical and scholarly trends and debates as they discuss a wide range of genres and kinds of publication (including fictional and non-fictional prose, verse miscellanies, abridgements, sermons, religious controversy) and of authors and booksellers (including Lucy Hutchinson, Richard Baxter, Thomas Burnet, Elizabeth Rowe, John Dryden, and Samuel Taylor Coleridge, Lucy Hutchinson, Henry Maundrell, John Nourse; Jonathan Swift, Samuel Richardson, John Tillotson, Isaac Watts and John Wesley).

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