Data from: Quantitative ornithology with a commercial marine radar: standard-target calibration, target detection and tracking, and measurement of echoes from individuals and flocks
Marine surveillance radars are commonly used for radar ornithology, but they are rarely calibrated. This prevents them from measuring the radar cross-sections (RCS) of the birds under study. Furthermore, if the birds are aggregated too closely for the radar to resolve them individually, the bulk vol...
Main Authors: | , |
---|---|
Language: | unknown |
Published: |
2016
|
Subjects: | |
Online Access: | http://nbn-resolving.org/urn:nbn:nl:ui:13-7v-ywr9 https://easy.dans.knaw.nl/ui/datasets/id/easy-dataset:96037 |
id |
ftdans:oai:easy.dans.knaw.nl:easy-dataset:96037 |
---|---|
record_format |
openpolar |
spelling |
ftdans:oai:easy.dans.knaw.nl:easy-dataset:96037 2023-07-02T03:33:47+02:00 Data from: Quantitative ornithology with a commercial marine radar: standard-target calibration, target detection and tracking, and measurement of echoes from individuals and flocks Urmy, Samuel S. Warren, Joseph D. 2016-11-08T23:24:40.000+01:00 http://nbn-resolving.org/urn:nbn:nl:ui:13-7v-ywr9 https://easy.dans.knaw.nl/ui/datasets/id/easy-dataset:96037 unknown doi:10.5061/dryad.45gb4/1 doi:10.1111/2041-210x.12699 http://nbn-resolving.org/urn:nbn:nl:ui:13-7v-ywr9 doi:10.5061/dryad.45gb4 https://easy.dans.knaw.nl/ui/datasets/id/easy-dataset:96037 OPEN_ACCESS: The data are archived in Easy, they are accessible elsewhere through the DOI https://dans.knaw.nl/en/about/organisation-and-policy/legal-information/DANSLicence.pdf Life sciences medicine and health care 2016 ftdans https://doi.org/10.5061/dryad.45gb4/110.1111/2041-210x.1269910.5061/dryad.45gb4 2023-06-13T13:23:49Z Marine surveillance radars are commonly used for radar ornithology, but they are rarely calibrated. This prevents them from measuring the radar cross-sections (RCS) of the birds under study. Furthermore, if the birds are aggregated too closely for the radar to resolve them individually, the bulk volume reflectivity cannot be translated into a numerical density. We calibrated a commercial off-the-shelf marine radar using a standard spherical target of known RCS. Once calibrated, the radar was used to measure the RCS of common and roseate terns (Sterna hirundo L. and Sterna dougallii Montagu) tracked from a land-based installation at their breeding colony on Great Gull Island, NY, USA. We also integrated echoes from flocks of terns, comparing these total flock cross-sections with visual counts from photos taken at the same time as the radar measurements. The radar's calibration parameters were determined with 1% error. RCS measurements made after calibration were expected to be accurate within ±2 dB. Mean tern RCS was estimated at -28 dB relative to one square meter (dBsm), agreeing in magnitude with a simple theoretical model. RCS was 3-4 dB higher when birds’ aspect angles were broadside to the radar beam compared with head- or tail-on. Integrated flock cross-section was linearly related to the number of birds. The slope of this line, an independent estimate of RCS, was -32 dBsm, within an order of magnitude of the estimate from individual birds, and near the middle of the frequency distribution of RCS values. These results indicate that a calibrated marine radar can count the birds in an aggregation via echo integration. Field calibration of marine radars is practical, enables useful measurements, and should be done more often. Other/Unknown Material Sterna hirundo Data Archiving and Networked Services (DANS): EASY (KNAW - Koninklijke Nederlandse Akademie van Wetenschappen) Gull Island ENVELOPE(-55.315,-55.315,49.533,49.533) Montagu ENVELOPE(-26.333,-26.333,-58.417,-58.417) |
institution |
Open Polar |
collection |
Data Archiving and Networked Services (DANS): EASY (KNAW - Koninklijke Nederlandse Akademie van Wetenschappen) |
op_collection_id |
ftdans |
language |
unknown |
topic |
Life sciences medicine and health care |
spellingShingle |
Life sciences medicine and health care Urmy, Samuel S. Warren, Joseph D. Data from: Quantitative ornithology with a commercial marine radar: standard-target calibration, target detection and tracking, and measurement of echoes from individuals and flocks |
topic_facet |
Life sciences medicine and health care |
description |
Marine surveillance radars are commonly used for radar ornithology, but they are rarely calibrated. This prevents them from measuring the radar cross-sections (RCS) of the birds under study. Furthermore, if the birds are aggregated too closely for the radar to resolve them individually, the bulk volume reflectivity cannot be translated into a numerical density. We calibrated a commercial off-the-shelf marine radar using a standard spherical target of known RCS. Once calibrated, the radar was used to measure the RCS of common and roseate terns (Sterna hirundo L. and Sterna dougallii Montagu) tracked from a land-based installation at their breeding colony on Great Gull Island, NY, USA. We also integrated echoes from flocks of terns, comparing these total flock cross-sections with visual counts from photos taken at the same time as the radar measurements. The radar's calibration parameters were determined with 1% error. RCS measurements made after calibration were expected to be accurate within ±2 dB. Mean tern RCS was estimated at -28 dB relative to one square meter (dBsm), agreeing in magnitude with a simple theoretical model. RCS was 3-4 dB higher when birds’ aspect angles were broadside to the radar beam compared with head- or tail-on. Integrated flock cross-section was linearly related to the number of birds. The slope of this line, an independent estimate of RCS, was -32 dBsm, within an order of magnitude of the estimate from individual birds, and near the middle of the frequency distribution of RCS values. These results indicate that a calibrated marine radar can count the birds in an aggregation via echo integration. Field calibration of marine radars is practical, enables useful measurements, and should be done more often. |
author |
Urmy, Samuel S. Warren, Joseph D. |
author_facet |
Urmy, Samuel S. Warren, Joseph D. |
author_sort |
Urmy, Samuel S. |
title |
Data from: Quantitative ornithology with a commercial marine radar: standard-target calibration, target detection and tracking, and measurement of echoes from individuals and flocks |
title_short |
Data from: Quantitative ornithology with a commercial marine radar: standard-target calibration, target detection and tracking, and measurement of echoes from individuals and flocks |
title_full |
Data from: Quantitative ornithology with a commercial marine radar: standard-target calibration, target detection and tracking, and measurement of echoes from individuals and flocks |
title_fullStr |
Data from: Quantitative ornithology with a commercial marine radar: standard-target calibration, target detection and tracking, and measurement of echoes from individuals and flocks |
title_full_unstemmed |
Data from: Quantitative ornithology with a commercial marine radar: standard-target calibration, target detection and tracking, and measurement of echoes from individuals and flocks |
title_sort |
data from: quantitative ornithology with a commercial marine radar: standard-target calibration, target detection and tracking, and measurement of echoes from individuals and flocks |
publishDate |
2016 |
url |
http://nbn-resolving.org/urn:nbn:nl:ui:13-7v-ywr9 https://easy.dans.knaw.nl/ui/datasets/id/easy-dataset:96037 |
long_lat |
ENVELOPE(-55.315,-55.315,49.533,49.533) ENVELOPE(-26.333,-26.333,-58.417,-58.417) |
geographic |
Gull Island Montagu |
geographic_facet |
Gull Island Montagu |
genre |
Sterna hirundo |
genre_facet |
Sterna hirundo |
op_relation |
doi:10.5061/dryad.45gb4/1 doi:10.1111/2041-210x.12699 http://nbn-resolving.org/urn:nbn:nl:ui:13-7v-ywr9 doi:10.5061/dryad.45gb4 https://easy.dans.knaw.nl/ui/datasets/id/easy-dataset:96037 |
op_rights |
OPEN_ACCESS: The data are archived in Easy, they are accessible elsewhere through the DOI https://dans.knaw.nl/en/about/organisation-and-policy/legal-information/DANSLicence.pdf |
op_doi |
https://doi.org/10.5061/dryad.45gb4/110.1111/2041-210x.1269910.5061/dryad.45gb4 |
_version_ |
1770273883024261120 |