A Global Unmanned Aircraft System
(UAS) Observational Network
Nikki
NikkiPrivé
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August
August16162006
2006
Purpose
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Improve observations in data poor regions
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Polar regions
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Southern hemisphere
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Oceans
Provide consistent vertical profiles
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high resolution and accuracy for climate studies
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long term observations to detect trends
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Eulerian observations on a grid
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Improve operational forecasting
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Satellite verification
Complementary observations
to existing ground and
satellite network.
Combine UAS observations
with satellite, buoy, and
surface data for improved
analyses. Satellites provide
broad coverage, UAS would
provide in situ observations
and high resolution vertical
profiles to expand the
usefulness of the data.
Proposed UAS Network
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36 High Altitude UAS (such as Global Hawk)
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30+ hr/14,000 miles
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flies at 50-65,000 ft, above weather and commercial airspace
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payload 1960 lbs
12 base stations around the globe
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3 UAS stationed at each base
244 fixed observational points
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each point visited once every three days
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on icosahedral grid over oceans and poles
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buoys colocated at oceanic points
Adaptive observations between points as desired
Proposed UAS Routes
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Each observational point sampled every third day
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Accurately determine atmospheric trends
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Each UAS assigned a particular route
Viability of UAS Network
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Goal: 97% reliability
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Most points easily reached on schedule (100%)
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Use ECMWF reanalysis wind fields to calculate flight times
and statistics
Handful of points near southern hemisphere jet
stream were sometimes difficult to reach on
scheduled due to strong headwinds
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Usually less than 5 minute delay
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On-schedule drops possible >98% of the time
Base Stations
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Located in friendly countries with proximity to target
region
Takeoff criteria for Global Hawk
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crosswind maximum: 10 kt
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headwind maximum: 30 kt
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no icing
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presume UAS will fly around nearby icing conditions
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no standing water on runway
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visibility: assume 500 m minimum
Base Stations
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Dataset: Integrated Surface Hourly data set TD3505 from
the National Climatic Data Center
Crosswinds and icing the most stringent parameters for
takeoff
Suitable airports hard to find in southern hemisphere
midlatitudes and Arctic
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strong winds
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few major airports with multiple runways
Islands in tropical Pacific have only basic airport facilities
and few available surface observations
Puntas Arenas, Chile
Viable Base Stations
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Lihue Airpot, Hawaii
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Inverness, UK
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Elmendorf AFB, Alaska
(Anchorage)
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Port Elizabeth, South
Africa
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Aitutaki, Cook Islands
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Yap, Micronesia
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Puntas Arenas, Chile
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Diego Garcia, B.I.O.T.
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Invercargill, NZ
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Seymour, Galapagos
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Geraldton, Australia
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Praia, Cape Verde
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Nadi, Fiji
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Hokitika, NZ
Instrumentation Suite - Sondes
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Dropsondes
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high vertical resolution
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high accuracy observation of temperature (0.1ºC), humidity for climate
observations
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develop new lightweight sondes to meet goals
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inexpensive “weather” sondes dropped between observational points
Sidesondes
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Sondes which fall to a set pressure level and drift for several days
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Significant instrument development needed
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Multiple sondes dropped at each observational point
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Adaptive observations for operational forecasting
QuickTime™ and a
decompressor
are needed to see this picture.
Instrumentation Suite – In Situ
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Instrument packages can be swapped as needed
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Routine measurements
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Ozone, water vapor, CO, CO2
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CCN and ice particles
Intensive observing flights
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Chemical species
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Cloud water and droplets
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Aerosol composition
Remote sensors
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Large payload on high-altitude UAS (1000 kg on
Global Hawk)
Radiometers, lidar, scatterometers, radars, infrared
spectrometers all viable
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Select instrument package which will give new data and
not just duplicate existing satellite observations
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Stronger signal than satellites due to lower altitude
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Higher resolution (but smaller coverage area) than
satellites
Future Work
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Observing System Simulation Experiment to
determine benefits for operational forecasting
Development of sonde and instrumentation
technology with integration onto UAS platforms
Single base as a “test” of UAS observing concept to
work out the kinks and push instrumentation
development