VHF signal power suppression in stratiform and convective precipitation

Previous studies have indicated that VHF clear-air radar return strengths are reduced during periods of precipitation. This study aims to examine whether the type of precipitation, stratiform and convective precipitation types are identified, has any impact on the relationships previously observed a...

Mô tả đầy đủ

Đã lưu trong:
Chi tiết thư mục
Tác giả chính: A. J., McDonald, K. P., Monahan, D. A., Hooper
Ngôn ngữ:English
Năm xuất bản: Copernicus Publications 2018
Chủ đề:
Truy cập Trực tuyến:http://lrc.quangbinhuni.edu.vn:8181/dspace/handle/DHQB_123456789/4031
Tags: Thêm thẻ
Không có thẻ, Hãy là người đầu tiên gắn thẻ bản ghi này!
id oai:localhost:DHQB_123456789-4031
recordtype dspace
spelling oai:localhost:DHQB_123456789-40312018-10-22T08:44:26Z VHF signal power suppression in stratiform and convective precipitation A. J., McDonald K. P., Monahan D. A., Hooper Meteorology and atmospheric dynamics (Precipitation) Radio science (Remote sensing; Instruments and techniques) Previous studies have indicated that VHF clear-air radar return strengths are reduced during periods of precipitation. This study aims to examine whether the type of precipitation, stratiform and convective precipitation types are identified, has any impact on the relationships previously observed and to examine the possible mechanisms which produce this phenomenon. This study uses a combination of UHF and VHF wind-profiler data to define periods associated with stratiform and convective precipitation. This identification is achieved using an algorithm which examines the range squared corrected signal to noise ratio of the UHF returns for a bright band signature for stratiform precipitation. Regions associated with convective rainfall have been defined by identifying regions of enhanced range corrected signal to noise ratio that do not display a bright band structure and that are relatively uniform until a region above the melting layer. <P style="line-height: 20px;"> This study uses a total of 68 days, which incorporated significant periods of surface rainfall, between 31 August 2000 and 28 February 2002 inclusive from Aberystwyth (52.4° N, 4.1° W). Examination suggests that both precipitation types produce similar magnitude reductions in VHF signal power on average. However, the frequency of occurrence of statistically significant reductions in VHF signal power are very different. In the altitude range 2-4 km stratiform precipitation is related to VHF signal suppression approximately 50% of the time while in convective precipitation suppression is observed only 27% of the time. This statistical result suggests that evaporation, which occurs more often in stratiform precipitation, is important in reducing the small-scale irregularities in humidity and thereby the radio refractive index. A detailed case study presented also suggests that evaporation reducing small-scale irregularities in humidity may contribute to the observed VHF signal suppression. 2018-09-10T02:52:01Z 2018-09-10T02:52:01Z 2007-03-07 0992-7689 (Print); 1432-0576 (Online) http://lrc.quangbinhuni.edu.vn:8181/dspace/handle/DHQB_123456789/4031 en Copernicus Publications
institution Trung tâm Học liệu Đại học Quảng Bình (Dspace)
collection Trung tâm Học liệu Đại học Quảng Bình (Dspace)
language English
topic Meteorology and atmospheric dynamics (Precipitation)
Radio science (Remote sensing; Instruments and techniques)
spellingShingle Meteorology and atmospheric dynamics (Precipitation)
Radio science (Remote sensing; Instruments and techniques)
A. J., McDonald
K. P., Monahan
D. A., Hooper
VHF signal power suppression in stratiform and convective precipitation
description Previous studies have indicated that VHF clear-air radar return strengths are reduced during periods of precipitation. This study aims to examine whether the type of precipitation, stratiform and convective precipitation types are identified, has any impact on the relationships previously observed and to examine the possible mechanisms which produce this phenomenon. This study uses a combination of UHF and VHF wind-profiler data to define periods associated with stratiform and convective precipitation. This identification is achieved using an algorithm which examines the range squared corrected signal to noise ratio of the UHF returns for a bright band signature for stratiform precipitation. Regions associated with convective rainfall have been defined by identifying regions of enhanced range corrected signal to noise ratio that do not display a bright band structure and that are relatively uniform until a region above the melting layer. <P style="line-height: 20px;"> This study uses a total of 68 days, which incorporated significant periods of surface rainfall, between 31 August 2000 and 28 February 2002 inclusive from Aberystwyth (52.4° N, 4.1° W). Examination suggests that both precipitation types produce similar magnitude reductions in VHF signal power on average. However, the frequency of occurrence of statistically significant reductions in VHF signal power are very different. In the altitude range 2-4 km stratiform precipitation is related to VHF signal suppression approximately 50% of the time while in convective precipitation suppression is observed only 27% of the time. This statistical result suggests that evaporation, which occurs more often in stratiform precipitation, is important in reducing the small-scale irregularities in humidity and thereby the radio refractive index. A detailed case study presented also suggests that evaporation reducing small-scale irregularities in humidity may contribute to the observed VHF signal suppression.
author A. J., McDonald
K. P., Monahan
D. A., Hooper
author_facet A. J., McDonald
K. P., Monahan
D. A., Hooper
author_sort A. J., McDonald
title VHF signal power suppression in stratiform and convective precipitation
title_short VHF signal power suppression in stratiform and convective precipitation
title_full VHF signal power suppression in stratiform and convective precipitation
title_fullStr VHF signal power suppression in stratiform and convective precipitation
title_full_unstemmed VHF signal power suppression in stratiform and convective precipitation
title_sort vhf signal power suppression in stratiform and convective precipitation
publisher Copernicus Publications
publishDate 2018
url http://lrc.quangbinhuni.edu.vn:8181/dspace/handle/DHQB_123456789/4031
_version_ 1717292467843235840
score 9,463379