Transcript Sensor Classification System Canadian Version: Siting Classification Rodica Nitu Sensor Classification System: “Canadian Version” • To ensure international consistency, at this time the.

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Sensor Classification System
Canadian Version: Siting Classification
Rodica Nitu
Sensor Classification System: “Canadian Version”
• To ensure international consistency, at this time the ‘Maintained
Performance’ portion of the Sensor Classification System (A-E) is
awaiting international input.
• The Sensor Classification System is to be applied to ‘existing’ sites.
The Meteo-France version works well when applied to ‘green field’
sites but omits many siting bias potentials when applied to an
existing network.
• The ‘Sensor Siting’ portion (1-5) of the system required a
‘Canadianized’ version and is actively being proposed for use. The
Maintained Performance can easily be added later and will not
require additional field trips.
• Canadian version can be used to assess both existing and green
field sites with the green field classification re-assessed before data
is released.
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System Implementation Overview 1
• With consideration to the many different networks and sensors gathering data
across Canada, both manual and automated for a single parameter type, it would
be far too cumbersome to include them all into a single classification assessment
document.
• For simplicity, the Canadian version will initially focus on the MSC sensor suite
approved for reference and supplimental autostations (RCS/SWX) .
• Classification system has been expanded to include 8 automated sensor
parameters (pressure sensor on hold). Only a single classification is required for
solar radiation.
• Additional future documents will be put together to include other network sensors
(ie. manual, alternate auto sensors, etc.) for comparable classification results.
• For system sustainability and continual classification updates, it must be applied by
the routine site technician. To be applied by a ‘specialist’ would not be sustainable
in a timely fashion with regards to siting changes over time.
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System Implementation Overview 2
• As much as possible, the basic criteria listed in the Meteo-France
version has been preserved and further expanded upon.
• Since assessments are to be done by routine technical staff,
subjectiveness had to be reduced and clarification added to
ensure homogenous results across the country. This resulted in an
increase in the document size.
• As an archive to note future changes, avoidance of classification
level flip-flopping and to supply a document both for supervisors and
data users, simple ‘result’ forms are a requirement to be filled in.
• A full classification assessment is to be done every 5 years to
coincide with established meta-data updates (photos, drawings,
etc.) where the forms are completed and archived.
• Single sensor classification updates are completed and archived
anytime a change in classification level is confirmed. It can be ‘back
dated’ if known.
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System Implementation Overview 3
• A numbering system has been added to identify each classification
criteria so that it can easily be identified on the assessment archive
form. A single page is utilized for each parameter or sensor.
• With use of detailed site knowledge, good meta-data, drawings,
photos, area maps, graphics programs and Google Earth, a full
siting classification can be done without a field trip for many sites.
• If an assessment or measurement for a specific criteria is between
class levels, the numerically higher number is used.
• The classification system has been worded to ensure that
terminology does not refer to a siting range of “good to poor”.
Rather, the 1-5 range refers to “area of representativeness”. This
is to not offend the inclusion of other agencies with specific siting
requirements to use this system.
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Example Temp
Class1 criteria:
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Example
Archive Form:
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Siting Classification variations from Meteo-France 1
• Temperature and Humidity have been separated into distinct
classifications. Although identical for siting criteria, this is necessary since
they may often have different ‘Maintained Performance’ results.
• The Tipping Bucket Rain Gauge has its own classification as ‘Rainfall
Intensity’ and is not considered as a ‘Precipitation All Weather Gauge’.
Each can have Class 1 siting for its own intended purpose.
• The surface heating influence distance radius rings have been altered to
remove the ‘annulus’ area for simplicity of assessment.
• Surface Wind height has a criteria of 10 meters +/- 1m. This is required for
intercomparison purposes.
• The ‘Precipitation Wind’ sensor (formerly 2 Meter Wind) has its own
classification since its purpose should not be included with the 10 Meter
Surface Wind classification.
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Siting Classification variations from Meteo-France 2
• Bias onto Temperature and Humidity sensors caused by local
infrastructure (ie. electrical boxes, mounting structures, etc.) need
to be subjectively included as criteria.
• Precipitation AWG needs is own siting classification from other
‘liquid precipitation only’ sensors due to considerable siting and
height differences.
• Double Shielded on a Precipitation AWG (ie. DFIR) is a
requirement for Class 1.
• The use of a ‘wind shield’ is a requirement for Precipitation AWG
classes 2, 3 and 4 to differentiate from ‘unshielded’.
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Siting Classification variations from Meteo-France 3
• Optimum distance, height and influences for the Precipitation Wind
and Snow Depth sensors needed to be assumed where
established standards do not exist.
• Influences from nearby aircraft movement, area snow removal
methods and nearby ground cover irrigation need consideration.
• A specified minimal amount of mid-day shading onto the
temperature and humidity enclosure is assessed for each class
level.
• Additional detail has been supplied to assess the amount of level
area surrounding sensors to lessen assessment subjectiveness .
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Siting Classification variations from Meteo-France 4
• Wherever height/distance requirements such as 2:1, 4:1, 10:1. etc.
are used, angle measurements are supplied to assist the
technician with a scope.
• Where it is needed to measure a percentage of a ringed area for
surface heating, these percentages are also given as square
meters and square footage to assist assessment.
• The term ‘effective height’ is used to explain the horizontal
measurement point reference (ie. above the precipitation sensor
rim, from eye height at the base of the wind tower, etc.).
• To surround a precipitation sensor with trees as a natural DFIR, to
be more realistic, its criteria is to surround by a minimum of 300
degrees.
• Even if only a seasonal occurrence (not necessarily at the time of
assessment) of a water collection area, it is still considered as an
expanse of water.
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Siting Classification variations from Meteo-France 5
• Wherever height/distance requirements such as 2:1, 4:1,
10:1. etc. are used, angle measurements are given to
assist the technician with a scope.
• The height of anticipated maximum snow depth is a
classification criteria for Temperature, Humidity and
Precipitation AWG.
• The assessments can be done at any time but are
generally considered as taking place in mid-summer
due to some seasonal bias variability;
– Changing tree foliage affecting shade/wind/precipitation
– Snow pack and harvesting affecting wind ground friction index
– Height of wind sensors changing with increasing snow pack
level
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