Document
Atmospheric Measurements for
Flight Test at NASA’s Neil A.
Armstrong Flight Research
Center
Edward H. Teets Jr.
Sr. Aerospace Meteorologist
NASA Armstrong Flight Research Center ,
Edwards AFB, Edwards CA
Background:
1987 Graduate of the University of Utah (B.S. Meteorology)
1993 Graduate of the University of Nevada - Reno (UNR)
(M.S. Atmospheric Physics)
Desert Research Institute 1990 - 1993
NASA Atmospheric Science 29 years
Who’s interested in Good high
Altitude Atmospheric Data?
• Advance DoD Hypersonics
• Commercial Space
• NASA Hypersonics
• NASA/DOD Space
• NASA Flight Opportunities
• NASA Aeronautics
• NASA Science M ission (Earth Sciences)
• Actually Everyone!
How does weather impact flight
research?
Flight safety
Mission planning
Flight on - condition
Post - flight engineering
Flight Safety
Avoid hazardous weather conditions
Thunderstorms (hail and lightning)
Turbulence
High winds
Clouds and/or precipitation
Range safety
People and property in local communities
Mission Planning
Flight objectives
Decisions based on forecasts and observations (crew
briefings)
Criteria for Go/No Go
Weather limits/constraints
Operational guidelines (flight cards)
Primary and secondary objectives
Post - flight engineering
Atmospheric reference for air data
calibrations
Determine errors in aircraft measurements
Air pressure Pressure altitude Mach number Airspeed
Use weather balloon observations to measure
pressure, temperature and wind
Post - flight engineering (continued)
Interpolate for flight time and trends during the day
Correct RADAR measurements for atmospheric
refraction
Weather Tools
• Rawinsonde Balloons • Jimspheres • Tethered Sondes • Wind Towers • NAM, RAP, GFS, Global Ensemble, GEOS - 5 models • LIDARs • RADARs • SODARs
Where are we Located?
L A AFRC
Rogers Dry Lake Bed
Shaped Sonic Boom Demonstration Aircraft (SSBD)
Stratospheric Observatory for
Infared Astronomy (SOFIA)
NASA Earth Science
:
ERAST Helios
Phantom Eye Liquid H2
NASA’s IKHANA Predator B
Hypersonic Research Mach 9.6 (7000mph)
Hypersonics
HTV - 2 4/2010 & 8/2011
X - 51 5/2010, 3/2011, 8/2012, 5/2013
AHW 11/2011
Global Hawks
18 Jan 2010
Global Hawk Flight Area for KQX Refueling
Global Hawk “Poor Man’s Calibration”
Climatology
• Understanding the Atmosphere
– Surface behavior
• Seasonal vs time of day – Temperature – Winds – Precipitation
– Upper Air profile
• Seasonal – Temperature – Winds – Moisture Mountains Mountains
Surface Winds at Edwards AFB
Temperature Standards
EDW Monthly Upper Atmospheric Winds
Edwards AFB Monthly Rainfall 1942 - 2015 7.0 Ave since 1942 Monthly Max Ave since 1984 6.0 5.0 4.0 3.0 Rain, inches Monsoon Moisture 2.0 1.0 0.0
Tools of the Trade
High Altitude Lidar for
Atmospheric
Sensing (HALAS) Overview at
NASA Armstrong
Testing Locations – NASA - Armstrong
9/16/2016 35
HALAS at Armstrong
UV LIDAR
HALAS Overview
Technology Oveview
1. Ultraviolet laser light is emitted and scatters off air molecules and aerosols 4. Range - resolved, atmospheric parameters (wind speed/direction, temperature, density, water vapor, 2. Backscattered light is received and mass fractions) are measured with telescope and filtered to directly and simultaneously remove solar background 3. Filtered backscatter is analyzed in comparison with laser reference using Fabry - Perot Interferometer and Raman channel
Data Product Retrieval
UV LIDAR makes direct measurements of wind speed, temperature, and density Parameter Atmospheric Effect on Scattered Signal Effect on Output Phenomenon Wind Speed Change in wind speed Wavelength of return Etalon ring (fringe) radii shifts shifts Density Density of air mass increases Scattering of laser Area under the fringe increases increases Temperature Temperature of air mass Wider spectrum return Fringe broadens – width increases increases Doppler Shift Aerosol Signal Molecular Signal Sunlight Signal Intensity Zero Wind Wavelength
Rayleigh and Raman
Scattering
- 1 Rayleigh • Sum of Cabannes line (0.03 cm wide), rotational Raman and vibrational Raman scattering (weak contribution compared to the Cabannes lines) scattering*: • The scattered light is shifted by an amount specific to the species and Raman scattering: elastic scattered light is filtered out - 1 • N : 2,331 cm Species identified - 1 • O :1,556 cm - 1 • H O: 3,657 cm by the Raman shift.
* R.B. Miles, W.R. Lempert, J.N. Forkey, “Laser Rayleigh Scattering,” Meas. Sci. and Technol. 12 (2001)
Why HALAS vs Weather
Balloons
Representative High Altitude
Density
Parameter Value Date/time (UTC) Azimuth/Elevation 0 ° /90 ° Integration time 59.7 min Balloon launch (UTC) Balloon Max Altitude 19.3km (63,320ft) CCD gain 200 CCD shift rate 500ns Laser power 11.5W Uncertainty Ratio (with Typical Radiosonde Expected Response) Typical sonde uncertainty • Typical balloon uncertainty at 40km (131kft) is ~30% (dashed line) vs HALAS uncertainty of ~2% Actual balloon sonde uncertainty* * Balloon burst at 19.3km; typical high altitude balloons burst at 40km Representative Standoff Winds Set 384 Parameter Value Average is over 20 Azimuthal views (40 min total) Date/time (UTC) Balloon exits Azimuth/Elevation (45,90,135,180,225) ° /45 ° HALAS Zone Integration time 2 min/azimuth Balloon launch (UTC) Balloon distance; max altitude 170.6km; 32km (559,711ft; 104,987ft) CCD gain 200 CCD shift rate 500ns Laser power 11.5W Scan area 27km 3D balloon track Balloon exits HALAS Zone
Representative Density
3D balloon track Balloon popped Plot shows the relative difference between the balloon and the HALAS data, not uncertainty
Representative Wind Speed/Direction
Parameter Value Date/time (UTC) 3/6/2015 (20:44) Azimuth/Elevation (0,90,180,270) ° /65 ° Integration time 6 min/azm AF Balloon launch (UTC) 3/6/2015 21:00 Balloon distance / max altitude 37mi (estimate)/ 82,100ft CCD gain 95 CCD shift rate 500ns Laser power 11.2W • Plots marks time and location difference between balloon and HALAS • 3D ground track not available from Air Force data stream. Distances are estimated from average of multiple balloon launches before and after this launch
Temperature Estimations
Preliminary (Un - Optimized) Preliminary (Un - Optimized) Initial (Not Optimized) HALAS Temperature Estimates: Night [left], Day [right] • Initial temperature results do not reflect the full capability of HALAS • Upgrades are being implemented to enhance the temperature measurement capability under Phase 3 of HALAS – Upgrades will allow higher spectral resolution and better uncertainties
Water Vapor
• Water vapor not part of original effort but were added due to interest from current and future customers • Water vapor measurements show great promise for future implementation – Tracks well with balloon and provides greater resolution (30m)
HALAS on aircraft
• Significantly enhanced atmospheric data coverage – Allows for mapping of atmosphere along intended trajectory • Greater mission flexibility • Capability to support several different CONOPS • Improved measurement opportunity by beginning measurement above boundary layer and majority of cloud cover • Ability to provide additional data such as the characterization of aerosol conditions that could cause ablation or other issues to a flight vehicle
Potential Follow - On
1. Outer window 6. Interferometer Pressurized compartment 2. Receive telescope 7. Laser electronics Fiber optic 3. Laser head 8. Laser chiller 4. Dome mounting plate 9. Processing electronics 5. Raman channel 10. Control electronics 5 7
Trajectory Simulation
WX Sensor Deployment
Model 2000 Doppler SODAR
• Operates at 1600 - 2300
(2000) Hz
• Wind Profiles
– 60 meters AGL min – 740 meters AGL max – 20 meter intervals
• Sample Rate
– 1 cycle per 15 sec
• Averaging times
– 5 - 15 minutes
SODAR/Rawinsonde Comparisons
SODAR/Rawinsonde Comparisons
SODAR Profile Trends
SODAR Profile Trends (cont.)
Morning Wind Profile
Afternoon Wind Profile
AM Facsimile Profile
Pathfinder Plus Shear line Convective plume Convective plume
Model 4000 (miniSODAR)
• Operates at 4500 Hz
• Wind profiles
– 15 meter AGL min – 200 meter AGL max – 5 meter intervals
• Sample Rate
– 1 cycle per 4 sec
• Averaging times
– 1 - 5 minute
Radiosonde Balloon: Upper
Atmosphere measurements
• Measure winds and
altitude (GPS),
temperature, humidity
and Pressure
• Calculate density, pressure altitude,
dewpoint and liquid
water content
• Derive stability and
turbulence potential
High
Resolution
Balloon
Jimsphere for high resolution winds tracked by radar + Radio sonde package for thermodynamic data
Results
2005 Comparison: Velocity Difference due to offset in altitude 1 - 2 kts Direction Difference “ 3 - 5 deg Temperature Difference “ 1 Deg 2007 Comparison Velocity Difference 0.2 - 0.4 kts Direction Difference 0.1 – 0.3 deg Temperature Difference 0.15 deg
Hypersonics
HTV - 2 4/2010 & 8/2011
X - 51 5/2010, 3/2011, 8/2012, 5/2013
AHW 11/2011
Background Issues
• High altitude (to 50 km) parameters: pressure,
temperature, winds and density over 1000’s
km.
• Very difficult to measure by conventional
methods (Balloons).
• Range of sensors too extreme and no airdata
probes on vehicles due to severe aerothermal
heating during hypersonic speeds.
• GRAM standard deviations grow very large
with altitude.
Challenges
• Obtaining data in a region of the atmosphere
where data is very limited (ignorosphere).
• Formulate a Best Estimate Atmosphere (BEA)
that meets uncertainty requirements.
• Identify data sources that are/were projected
to become available and to determine how to
integrate these data.
• Develop a data analysis tool to evaluate the
data and produce a modeled atmosphere
based on representative data.
AHW Flight Path Nov 17, 2011
AHW Measurement Locations
o o
Example of Data Sources
• GEOS - 5 data – 3d instantaneous fields (no averaging) – 0.25 ° lat by 0.33 ° long to 72 km (236Kft) • NOGAPS – NAVY – Mandatory levels to .4 mb 52km (170 Kft) – 1 ° Lat x 1 ° Long • Radiosondes (Locations along flight track to 40 km (130 Kft) • Meteorological rocket data to 85km (280 Kft) • SABER data • COSMIC data • Satellite imagery • Global Reference Atmospheric Model (GRAM) - Earth v.2010 • No Mauna Loa LIDAR (down and clouds) • HALAS Lidar • ACLAIM lidar
AHW Data Sources
• Lower Atmosphere (SFC – 40km): – Radiosonde Balloons (6) – Models (2) • Middle Atmosphere (30 – 80km) – Rocketsonde (2) – Satellites (2) – GRAM - 2010 – Models (2) • Upper Atmosphere (70 – 120km) – GRAM - 2010 – Satellites (2) • Blending technique for overlap regions
Data Comparison
SABER vs GEOS 5
120000 12Z Apr 22 100000 80000 SABER T 60000 GEOS T Altitude, m 40000 20000 160 180 200 220 240 260 280 300 Temperature (K)
Data Comparison
Lidar vs GEOS 5
100000 06Z Apr 21 90000 80000 70000 60000 50000 Lidar T 40000 Altitude, m GEOS T 30000 20000 10000 160 180 200 220 240 260 280 Temperature (K)
NASA Meteorology Group
• Forecasts and courtesy briefings • Winds, gusts, visibility, clouds, particulates, water vapor loading • Hazards • Turbulence, icing, wind shear, T - storms, IFR conditions, mountain wave, lightning • Flight/project support • Crew briefs, T - x briefings • Full - time in - flight weather monitoring • Best - Estimate - Atmosphere • Trajectory analysis for atmospheric parameters • Airdata calibration • RVSM • Climatology • Project planning studies • Real - time ground measurements • Extensive weather station network • Mobile balloon launches • Portable for project specific applications Want more info: Edward H. Teets Jr.