Certainty or Flexibility of access
A Bureau of Meteorology perspective
Dr Bruce W Forgan
Observations and Infrastructure Division
Certainty or Flexibility of Access?
And the answer is…..
Certainty through minimizing measurement
uncertainty ……and
Flexibility of access in using new
communications systems for weather
measurement
RadComms 2014
Measure to Manage
Measurements of the earth and atmosphere provide the information we need to
manage the planet.
Informed management is essential for :
• Weather and climate forecasting
• Water availability;
• Climate change mitigation and adaptation;
• Response to natural disasters;
• Biodiversity protection;
• Monitoring the health of the ocean.
Earth measurements help us:
• Understand and predict changes in the environment;
• Manage natural resources to meet economic, social and environmental
needs.
RadComms 2014
What is Derived from Measurements?
The planet’s fundamental constituents and processes, including:
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Atmospheric water vapour and cloud liquid water
Precipitation including rain, ice (hail) and snow
Atmospheric temperature profiles
Soil moisture
Ocean salinity
Wind speed and direction
Land and sea surface temperature
Cloud temperature and cover
Ice cover
Vegetation biomass
Atmospheric chemistry, e.g. carbon, nitrogen and sulphur-based gases (CO2, CO, NO, SO2, etc.)
Suspended particulate matter (aerosols), e.g. volcanic ash, dust
 Spectrum is essential for observing the earth and delivering the outcomes
 It requires close cooperation in effective spectrum protection, management and
access to telecommunications 'meta data'
RadComms 2014
Microwave Measurement Technologies
Satellite & Surface – the How
Principles of Passive and Active Sensing
Passive Sensors
… measure electromagnetic radiation at microwave frequencies
emitted by constituents of the Earth and its atmosphere.
Active Sensors
… receive signals that they have transmitted, after these signals have
been reflected by land/ocean surfaces, by atmospheric
hydrometeors, or by variations in the refractive index of air.
RadComms 2014
Information for Users & Policy Development
(Environmental Intelligence)
RadComms 2014
Information Derived
with significant measurement uncertainty
RadComms 2014
Source of Measurement Uncertainty?
• Earth Observation community is an extensive user of bands in the spectrum
• Measurements in bands are used for deriving :
− molecular constituents
− greenhouse gases
− water vapour
− temperature
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Different parts of the band
inform for different heights
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Different bands equate to
different parameters
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Unknown sources in bands
- increase uncertainty
RadComms 2014
Basic Physics – radiative transfer equation
• Unexpected or too noisy
sources in a band corrupt the
derived values
RadComms 2014
Impact of Increased Uncertainty
from sources of unknown magnitude
RadComms 2014
Example of Surface-based Active
Remote Sensing
Surface-Based Active Sensing
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Doppler and non-Doppler weather radars S,C and X band (2.7…10 GHz)
– rainfall amount & intensity, wind speed and direction
Wind profiling radars (50 MHz, 1 GHz)
− Provide wind speed and direction profile from near ground to the stratosphere directly above
the radar, depending on the frequency.
RadComms 2014
Increased Uncertainty for Radar
C-band weather radars
• The Bureau operates over forty C-band weather radars;
• Over $200 million investment in hardware and service delivery
systems, plus $$ billions in value to the community, etc.
• Threatened by RLAN noise , particularly if airborne.
RadComms 2014
With satellite data to use
– forecast rain fields
RadComms 2014
What is there satellite data
was too uncertain to use?
RadComms 2014
Economic Value
The protection of spectrum used for passive and active Earth observations requires
a global perspective.
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Earth observations, whether made from space or from terrestrial networks, are shared
globally between meteorological agencies free of charge, for the benefit of all countries in
protecting life and property.
Australian Perspective
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Earth observations sector contributes an estimated $4 billion to the GDP as of Sep 2014.
Entirely dependent on Earth observation satellites funded and launched by other countries
with a 10-15 year lead time.
In return we provide science and mission support to these countries:
− Validation and calibration of sensors, e.g. CP2 radar in Brisbane for GPM, OzNet
Hydrological monitoring network (Australian Universities) .
− Satellite command and control, e.g. Bureau Turn Around Ranging Station for Chinese
FENGYUN geostationary satellites.
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A Spiky Beanstalk on my Roof
providing Cake!
RadComms 2014
Certainty in Measuring to Manage
Measurements - space and surface platforms
• Active and passive sensing in multiple noise/contamination free bands
Communicating
• Integral to measurement transfer process
• Essential for transmission of measurements and derived data
Informing
• Service delivery
• Point to point
• Broadcasting
 Spectrum is a shared resource to achieve mutually beneficial outcomes
RadComms 2014
Thank you…
'The one thing you can't trade for your heart's desire is your heart.'
Louis McMaster Bujold, Memory
Bruce W Forgan
03 9669 4111
b.forgan@bom.gov.au