Metrology for Extreme Environments
Tom Gardiner, NPL
Andrea Merlone, INRIM
EMPIR Environment Workshop
1st December 2015, INRIM
Welcome to the National Physical Laboratory
Contents
 Background
 Metrology challenges in the Arctic
 Metrology challenges in the Upper Atmosphere
Euramet Strategic Research
Agenda – Extreme Environments
• Providing reliable data is vital to meet
the challenge of climate change, and
in many cases such measurements
need to be made in extreme
environments.
• The Arctic and the Upper Atmosphere
are two key examples of extreme
environments where metrological
support is needed.
• The extreme ranges of variability of
the key-quantities measured requiring
higher accuracy than for other areas
need dedicated calibration procedures
and specific uncertainty evaluation.
• The logistical difficulties in reaching,
removing, handling instruments for
calibration campaigns require self
validating measurements and calibration
devices operating in extreme
environmental conditions
Why is the Artic important ?
 Effects of environmental change often seen first / amplified
in the Arctic, and the Arctic is a significant potential source
of positive feedback to climate change.
 A large number of EU member states have territorial,
scientific and commercial interests in the Arctic.
 Environmental monitoring in the Artic is therefore vital to
Europe since it influences climate change and adaption,
food supplies (fishing), shipping, energy security (oil and
gas), and biodiversity (terrestrial and aquatic).
 A unique multi-organisational, multi-disciplinary facility
exists at Ny Ålesund where many EU counties participate
in Polar research. Much of this research is currently done
without comparability and common traceability.
Break out session at Arctic Circle 2015
Why is metrology research needed in
the Arctic ?
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The extreme ranges of variability of the
key-quantities measured requiring higher
accuracy than for other areas need
dedicated calibration procedures and
specific uncertainty evaluation, not
available by usual calibration services.
The logistical difficulties in reaching,
removing, handling instruments for
calibration require self validating
measurement and calibration devices
operating in arctic-based research
stations.
Unique common calibration procedures,
improving the comparability of the
instruments response across research
groups.
An active collaboration between
metrologists and operators in defining
calibration procedures, and testing and
calibrating instrumentation.
-120
-140
-160
-180
95 96
97
98
99
-200
100
P / kPa
101
102
-30
103
-15
104
10510
0
T / °C
DP / Pa

-100
Why is metrology research needed in
the Arctic ?
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A centralised metrological
infrastructure to benefit all
researchers operating in the area, with
an agreed common implementation
plan.
Time, funds and risks reduced in
shipping instruments to national
calibration services.
Direct traceability to primary
standards of the System of Units,
arising from the involvement of
National Institutes of Metrology ,
reduces calibration uncertainty.
Improved comparability of data in
space and time, among different
systems and different research groups
and stations
ITS-90 fixed points.
Upper Atmospheric Requirements
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The upper atmosphere – the atmosphere above the boundary layer – is the
most important region for climate research and atmospheric science. The
composition and dynamics of the upper atmosphere determine the energy
distribution in global atmosphere which in turn drives the weather and climate
systems, and the long-range transport of pollutants around the globe.
It is one of the most challenging regions to make high quality traceable
measurements.
Global Climate Observing System (GCOS) Report 112 : “Shortcomings in
the design and implementation of the current upper-air measurement
network greatly limit the accuracy and detail of observations needed to
specify how climate has varied and changed above the Earth’s surface.
This deficit impacts our ability to accurately predict climate change, and
hence has potentially serious consequences in areas of high relevance to
society...”
This report also stresses the importance of traceability in upper atmospheric
measurements.
The need for metrological research and support in this area was highlighted at
a recent joint BIPM-WMO workshop (June 2015).
Water vapour trends in the
troposphere?
e.g.: Lindenberg 8km (0:00 UT)
Water vapour trends in the
troposphere?
e.g.: Lindenberg 8km (0:00 UT)
Freiberg
RKS-2
RKS-5
MARZ
RS80
RS92
Reference Measurements in the
Upper Atmosphere
 GCOS Reference Upper Air Network
 Network for ground-based reference observations for climate in the
free atmosphere in the frame of the Global Climate Observing
System, linked to WMO and UNEP.
 Currently 16 stations, envisaged to be a network of 30-40 sites across
the globe
 See www.gruan.org for more detail
GRUAN goals
 Provide long-term high-quality
upper-air climate records
 Constrain and calibrate data from
more spatially-comprehensive global
observing systems (including
satellites and current operational
radiosonde network)
 Fully characterize the properties of
the atmospheric column
 Characterize observational
uncertainties, with traceability to SI
units or accepted standards
 Comprehensive metadata collection
and documentation
 Validate observations through
deliberate measurement redundancy
Multiple instrument types all
providing measurements of the
same geophysical parameters.
Uncertainty example:
Daytime temperature Vaisala RS92
Sources of measurement uncertainty
(in order of importance):
 Sensor orientation
 Unknown radiation field
 Lab measurements of the radiative
heating
 Ventilation
 Ground check
 Calibration
 Time lag
Comparing atmospheric
measurements
 A crucial aspect of upper air measurements is that the results are
almost invariably integrated with or compared to other data sets (e.g.
assimilation into meteorological forecasts, satellite validation or
integration into atmospheric models).
 Co-location / co-incidence:
 Natural variability makes comparison of atmospheric measurement
particularly challenging.
 Need to consider the variability in time and space () when
comparing one measurement (m1 with uncertainty u1) against a
second measurement or model (m2 with uncertainty u2) :
m1  m2  k 2  u12  u 22
 In addition, it is necessary to identify any common elements of the
measurements or models, e.g. the underlying spectroscopy, that could
lead to correlated uncertainties in the comparison/combination of data
Comparing atmospheric
measurements
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Multiple instrument types all providing measurements of the same geophysical
parameters.
Example for regular water vapour/humidity measurements :
- Operational sondes (in-situ balloon-borne capacitance sensors)
- Research sondes (in-situ balloon-borne frost point hygrometers and laser
absorption sensors)
- Raman lidar (remote sensing vertical profile measurements, usually at
night)
- Microwave radiometer (remote sensing total column measurement with
some profile information)
- Solar pointing FTIR (remote sensing total column measurement with some
profile information, day-time only)
- GNSS (remote sensing total column measurement from GPS satellite
signals).
Need to establish comparability between these methods, addressing the
differences between the measurement techniques, including temporal and
spatial coverages and resolutions.
In Conclusion
 There is an urgent need for metrology support and
research in the environmental extremes of the Artic and
Upper Atmosphere.
 Need to combine the expertise achieved in the individual,
traditional fields of metrology into new interdisciplinary
and multidisciplinary strategies that can be applied in the
field.
 European NMI community ideally positioned to meet this
challenge, building on the underpinning metrology
developed in the MeteoMet EMRP projects.
 Outputs of research would have immediate impact on the
wide range of stakeholders making and using
measurements in these areas.
Questions ?