The AFIT of Today is the Air Force of Tomorrow. Enhanced ...€¦ · 2 2.5 180 ° W 135 ° W 90 °...
Transcript of The AFIT of Today is the Air Force of Tomorrow. Enhanced ...€¦ · 2 2.5 180 ° W 135 ° W 90 °...
1
The AFIT of Today is the Air Force of Tomorrow.
*Applied Research Solutions 50 Chestnut Suite, 240 Beavercreek OH 45440 USA **Southwestern Ohio Council for Higher Education 3155 Research Blvd, Ste 204 Dayton OH 45420
Enhanced Atmospheric Refraction and Radiative Transfer Analyses Merging Gridded Numerical
Weather Forecast and Satellite Data
Steven T. Fiorino, Michelle M. Via*, David C. Meier, Brannon J. Elmore**, and Kevin J. Keefer*
Air Force Institute of Technology, Center for Directed Energy
Department of Engineering Physics 2950 Hobson Way
Wright-Patterson AFB, OH 45433-7765
94th Annual American Meteorological Society Annual Meeting 18th Conference on Integrated Observing and Assimilation Systems for the
Atmosphere, Oceans, and Land Surface
2
The AFIT of Today is the Air Force of Tomorrow.
Overview
• Introduction/Goal of Research • Simulation Tool • Methodology • Results • Conclusion/Future Work
3
The AFIT of Today is the Air Force of Tomorrow.
Introduction
• Goal: couple numerical weather forecast, now-cast and satellite weather data with traditional climatologies for improved radiative transfer simulation – Higher fidelity path radiance for remote sensor applications – Higher resolution path refraction and optical turbulence
effects for DE propagation
• Core Analytical / Synoptic Observation Tools: – Laser Environmental Effects Definition and Reference
(LEEDR) – NOAA’s numerical weather prediction tools (i.e. Global
Forecast System) – NASA Aqua mission: AIRS and AMSU sensor suite
4
The AFIT of Today is the Air Force of Tomorrow.
Simulation Tool LEEDR
• Calculates line-by-line and spectral band radiative transfer solutions by creating correlated, physically realizable vertical profiles of meteorological data and environmental effects (e.g. gaseous and particle extinction, optical turbulence, and cloud free line of sight)
• Accesses terrestrial and marine atmospheric and particulate climatologies ‒Allows graphical access to and
export of probabilistic data from the Extreme and Percentile Environmental Reference Tables (ExPERT)
5
The AFIT of Today is the Air Force of Tomorrow.
LEEDR Worldwide Climatology
LEEDR ocean site selection map and upper air regions
Tropical
Polar-North
Polar-South
Midlat-South
Midlat-North
Desert (Red Shaded)
573 ExPERT (land) locations represented in LEEDR
6
The AFIT of Today is the Air Force of Tomorrow.
0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6
x 10-5
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]Pa
th R
adian
ce [W
cm
- 2 st
r- 1 µm
- 1]
Path Radiance200-K210-K220-K230-K240-K250-K260-K270-K280-K290-K300-K
5 10 15 20 250
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Microns
Path
Tra
nsm
ittan
ce (n
o un
its)
Path Transmittance vs. Microns
LEEDR Profiling Atmospheric Effects
0 20 40 60 80 100 120 140 160 18010
-2
100
102
104
106
108
Phase Function Angle
Dep
ende
nt V
aria
ble(
s)
Mean Molecular ScatteringMean Aerosol ScatteringMean Clouds and Rain
• LEEDR provides user multiple interactive views of atmospheric radiative effects
7
The AFIT of Today is the Air Force of Tomorrow.
• Description – Well mixed layer up to 1.5-2.0 km thick – Capped by temperature inversion
• Effects – Trap pollutants & aerosols – Location of wind shear – Atmospheric turbulence (surface layer) – Increasing RH & extinction with height
LEEDR Atmospheric Boundary Layer: Realistic Lapse Rate
θ T w NPotential Temp Temperature H2O mixing ratio Aerosol # conc.
Dry adiabatic temperature lapse rate
Moist (saturated) lapse rate
Lapse rate of dewpoint temperature
8
The AFIT of Today is the Air Force of Tomorrow.
LEEDR Standard vs Realistic Extinction Profiles
Left panel: Absorption and scattering effects on 355nm radiation from 4000 m altitude to the surface in a US Standard Atmosphere where the boundary layer is only defined with a constant aerosol concentration through the lowest 1250m. Right Panel: Same vertical path and boundary layer aerosol concentration as the left panel, but applying a realistic Dayton, OH summer atmosphere at 1400 local (LEEDR – calculated and Raman LIDAR Observation)
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
500
1000
1500
2000
2500
3000
3500
4000
Dependent Variable(s)
Alti
tude
(m)
WPAFB, 25 Jul 13, 1400L, 355nm, T = 74F, Td = 56.5F, GADS, BL Height = 1250m, Vis = 60km
Experimental Particle Extinction, 0305 Local (1/km)Experimental Particle Extinction, 0820 Local (1/km)Experimental Particle Extinction, 1345 Local (1/km)LEEDR Aerosol Scattering (1/km)LEEDR Total Extinction (1/km)LEEDR Molecular Scattering (1/km)LEEDR Aerosol Absorption (1/km)LEEDR Molecular Absorption (1/km)
9
The AFIT of Today is the Air Force of Tomorrow.
180° W 135° W 90° W 45° W 0° 45° E 90° E 135° E 180° E
90° S
45° S
0°
45° N
Irradiance Ratio: July, 20-1500m Altitudes, 5km Slant Path
90° N
0.5
1
1.5
2
2.5
180° W 135° W 90° W 45° W 0° 45° E 90° E 135° E 180° E
90° S
45° S
0°
45° N
Irradiance Ratio: January, 20-1500m Altitudes, 5km Slant Path
90° N
0.5
1
1.5
2
2.5• Ratios of HEL
irradiance; realistic aerosol environment over standard environment − Std: US Std Atm with 23km
Modtran Rural aerosols
• Realistic conditions at land sites are in general worse than standard in terms of DE propagation
LEEDR Realistic Atmospheres The Impact: Elevated Aerosol Extinction
Fiorino, Shirey, Via, Grahn, and Krizo, 2012 ‘Potential Impacts of Elevated Aerosol Layers on High Energy Laser Aerial Defense Engagements’. Proc. of SPIE Vol. 8380 83800T
10
The AFIT of Today is the Air Force of Tomorrow.
Air University: The Intellectual and Leadership Center of the Air Force Aim High…Fly - Fight - Win
LEEDR Path Radiance GUI
Important for Solar/Lunar Calculations!
11
The AFIT of Today is the Air Force of Tomorrow. The AFIT of Today is the Air Force of Tomorrow.
Air University: The Intellectual and Leadership Center of the Air Force Aim High…Fly - Fight - Win
LEEDR Path Radiance GUI Key Aspect: Earth-Sun-Moon Geometry
12
The AFIT of Today is the Air Force of Tomorrow.
Air University: The Intellectual and Leadership Center of the Air Force Aim High…Fly - Fight - Win
0.5 1 1.5 2 2.5 3
x 10-5
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]
Pat
h R
adia
nce
[W c
m- 2
str- 1
µm
- 1]
Path Radiance200-K210-K220-K230-K240-K250-K260-K270-K280-K290-K300-K
0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6
x 10-5
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]
Path
Rad
ianc
e [W
cm
- 2 s
tr- 1 µ
m- 1
]
Path Radiance200-K210-K220-K230-K240-K250-K260-K270-K280-K290-K300-K
LEEDR Path Radiance Tailored Derivation / Flexible Solutions
3 4 5 6 7 8 9 10
x 10-7
0
1
2
3
4
5
6
7x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]
Path
Rad
ianc
e [W
cm
- 2 st
r- 1 µm
- 1]
• Upward or downward looking spectral path radiance calculation fully incorporated into LEEDR Line-by-line Correlated-k Single scattering With / without aerosol
effects
0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6
x 10-5
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]
Pat
h R
adia
nce
[W c
m- 2
str- 1
µm
- 1]
200-K210-K220-K230-K240-K250-K260-K270-K280-K290-K300-KPlexus
13
The AFIT of Today is the Air Force of Tomorrow.
Air University: The Intellectual and Leadership Center of the Air Force Aim High…Fly - Fight - Win
Point to Point Apply atmospheric compensation
correction to improve aim, hit endpoint
Displaced Path Calculate actual path of laser
when aimed at endpoint
LEEDR Path Bending GUI Realitic Atmospheric Refractivity Profiles
14
The AFIT of Today is the Air Force of Tomorrow.
14 Air University: The Intellectual and Leadership Center of the Air Force
Aim High…Fly - Fight - Win
• Ingest gridded, 3D NWP-derived nowcast, forecast, post-event atmosphere to verify / enhance simulation
• Atmosphere for scenario’s propagation path interpolated from GFS grid data (GFS 1, GFS 2, etc)
Integrate gridded numerical Wx forecast data and remote sensor
profiles
Evaluate / compare atmospheric
characterization methods
Evaluate impact : Remote sensing and
Directed Energy Propagation Applications Optimize Path Bending /
Radiance code
Methodology Ingest Numerical Wx Prediction and Remote Sensor Data
Upgrade radiative transfer code tools (e.g. Path Bending, Path Radiance)
•Initial state: climo-based effects
15
The AFIT of Today is the Air Force of Tomorrow.
Air University: The Intellectual and Leadership Center of the Air Force Aim High…Fly - Fight - Win
Methodology NWP Impact: Extinction / RH Comparisons
0
500
1000
1500
2000
2500
3000
3500
4000
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16Dependent Variables
Alti
tude
(m)
NOMADS - 29 August 2013 - 550nm 1800 cycle + 27hrs
Molecular Absorption (1/km)Molecular Scattering (1/km)Aerosol Absorption (1/km)Aerosol Scattering (1/km)Total Absorption (1/km)Total Scattering (1/km)Total Extinction (1/km)
0
500
1000
1500
2000
2500
3000
3500
4000
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7Dependent Variables
Alti
tude
(m)
WPAFB ExPERT Site - Summer, 550nm 1500-1800L
20 30 40 50 60 70 80 90 1000
500
1000
1500
2000
2500
3000
3500
4000
RH %
Alti
tude
(m)
Relative Humidity (%) Comparison
NOMADS - 29 August 2013 (1800 Cycle +27hrs)
WPAFB ExPERT Site - Summer, 1500-1800L
LEEDR Extinction Profiles (using NWP)
LEEDR Extinction Profiles (using Climatology)
LEEDR RH Profiles (using NWP or Climatology)
16
The AFIT of Today is the Air Force of Tomorrow.
Air University: The Intellectual and Leadership Center of the Air Force Aim High…Fly - Fight - Win
Methodology Satellite-Derived Cn
2
• Atmospheric IR sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU on polar orbiting Aqua Satellite
• Global coverage provides vertical temperature profile (surface to 80km) at each sounding location
• Height assigned to pressure levels by adding each layer’s thicknesses
0
200
400
600
800
1000
200 220 240 260 280 300
Pres
sure
Lev
el (m
b)
Temperature (K)
RAOB Temp
Satellite Temp
𝑍𝑍2 − 𝑍𝑍1 = 𝑅𝑅𝑑𝑑 𝑇𝑇�𝑣𝑣𝑔𝑔𝑜𝑜
ln �𝑝𝑝1
𝑝𝑝2�
17
The AFIT of Today is the Air Force of Tomorrow.
• Thermal wind relationship used to derive vertical wind profiles
500
550
600
650
700
750
800
850
900
950
1000
0 50 100 150 200 250 300 350
Pres
sure
Lev
el (m
b)
Wind Direction
Satellite DataRAOB Data
500
550
600
650
700
750
800
850
900
950
1000
0 2 4 6 8 10 12 14 16 18 20
Pres
sure
Lev
el (m
b)Wind Speed (m/s)
Satellite DataRAOB Data
10-22
10-20
10-18
10-16
10-14
0
5
10
15
20
25
30
35
40Vertical Cn2 Profile
Turbulence Structure (Cn2)H
eigh
t (km
)
Richardson Number and KH/KM
ratio based on AIRS derived winds
14 Oct 2011 0746Z, Dayton, OH
Radiosonde Measured vs AIRS-derived Wind Profile
• Cn2 profile
calculated for each AIRS sounding location
( )2
22 2 ( )( )( ) = (0.714) v nzz
z nzC C − ∂
∂∇
v
KH/KM - modified Tatarski
• Vertical temperature and pressure profiles are used along with ∂Tv/∂Z and derived winds to calculate Cn
2
Methodology Satellite-Derived Cn
2
18
The AFIT of Today is the Air Force of Tomorrow.
Air University: The Intellectual and Leadership Center of the Air Force Aim High…Fly - Fight - Win
Results Path Bending: Accounting for Refractivity Variations
Path refractivity profile using an ExPERT (Climo) Atmosphere
Improved (4D) refractivity resolution significantly effects radiative transfer solutions
Path refractivity profile referencing 3 NOMADS (grid points) atmospheres along (nearest to) path
NO
MA
DS
#1
NO
MA
DS
#2
NO
MA
DS
#3
19
The AFIT of Today is the Air Force of Tomorrow.
Air University: The Intellectual and Leadership Center of the Air Force Aim High…Fly - Fight - Win
• Applied 3 ‘nearest neighbor’ gridded-NWP data for 4D refractivity calc
Results Path Bending: Accounting for Horizontal Variations
Laser Miss Distance Climo-derived – 64185.1m NWP-derived – 64297.3m
Improved resolution numerical weather data significantly effects light bending solutions
20
The AFIT of Today is the Air Force of Tomorrow.
Air University: The Intellectual and Leadership Center of the Air Force Aim High…Fly - Fight - Win
Results Path Bending: Accounting for Refractivity Variations
0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
x 10-6
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
Tran
smis
sion
Transmission vs. Wavelength
Wavelength (m)
Path TransmittanceStraight Slant Path
Path TransmittancePoint-to-Point Refracted Path
Path TransmittanceDisplaced Refracted Path
Cross-spectrum transmission comparison for 100km path. Refractivity is varied 10 times across the depicted spectral range.
Improved atmospheric (and refractivity) resolution significantly effects radiative transfer solutions
21
The AFIT of Today is the Air Force of Tomorrow.
Climo-derived AIRS-derived NWP-derived
Results Satellite Atmosphere Soundings: Winds / Temp Comparisons
Temperature
Climo-derived AIRS-derived NWP-derived Climo-derived AIRS-derived NWP-derived
Wind Speed Wind Direction
Dayton OH 12 Jan 2014, 18Z
22
The AFIT of Today is the Air Force of Tomorrow.
Climo-derived AIRS-derived NWP-derived
( )2
22 2 ( )( )( ) = (0.714) v nzz
z nzC C − ∂
∂∇
v
KH/KM - modified Tatarski Applying
Comparable Cn2 Profiles for Dayton OH 12 Jan 2014, 18Z
Results Satellite-derived Optical Turbulence Profiles - Comparisons
Satellite-derived optical turbulence with enhanced global 4D resolution can offer flexible radiative transfer solutions
23
The AFIT of Today is the Air Force of Tomorrow.
Conclusions
• Coupling NWP and/or satellite weather data with climatologies enhance fundamental radiative tranfer calculations (e.g. path radiance and refraction, optical turbulence)
• 4D-resolved optical turbulence and path refraction calculations will immediately benefit directed energy simulation tools (e.g. AFIT’s High Energy Laser Tactical Aid) and applications (e.g. laser communication system design)
• High resolution path radiance solutions can benefit industry and Government remote EO/IR sensor design and capabilities
24
The AFIT of Today is the Air Force of Tomorrow.
Future Work
• Model Verification and Validation (V&V) – Subject matter expert software / data accuracy review – Results accuracy: compare with field test campaigns
• Mature integration of gridded NWP data into radiative transfer (e.g. LEEDR) and DE propagation models (e.g. AFIT’s High Energy Laser End to End Operational Simulation and Tactical Decision Aid)
• Expand application of gridded NWP and remote satellite weather data – High resolution horizontal atmospheric variations – Enhance non-linear atmospheric effects analysis (e.g.
deep turbulence effects)
Upward or downward looking spectral path radiance calculation fully incorporated into LEEDR •Line-by-line •Correlated-k •Single scattering •With / without aerosol effects
Air Force Institute of Technology Center for Directed Energy Wright-Patterson AFB, Ohio
This study investigates the utility of integrating gridded numerical weather prediction (NWP) data, accessible through NOMADS (NOAA National Operational Model Archive & Distribution System), and satellite data from the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU) sensor suites for enhancing traditional radiative transfer calculations including atmospheric refraction and optical turbulence profiles. To support such analysis, the Laser Environmental Effects Definition and Reference (LEEDR) model’s radiative transfer code was modified to ingest and integrate such data with its probabilistic, geo-referenced atmospheric effects calculations. Leveraging LEEDR’s unique boundary layer treatment of temperature, pressure, water vapor, optical turbulence, and atmospheric particulate and hydrometeor vertical profiles as they relate to line-by-line or band-averaged layer extinction coefficients, these upgrades enabled more comprehensive, realistic 4D-resolved extinction analysis as well as light refraction and path radiance solutions at any wavelength between 350 nm and 8.6 m. The advantages of coupling numerical forecast, now-cast, and satellite weather data with atmospheric and aerosol climatologies for remote sensing and directed energy applications are quantified.
AMERICAN METEOROLOGICAL SOCIETY 94th Annual Meeting 2 - 6 February 2014
Enhanced Atmospheric Refraction and Radiative Transfer Analyses Merging Gridded Numerical Weather Forecast and Satellite Data
S. T. Fiorino, M. F. Via*, D. C. Meier, B. J. Elmore**, and K. J. Keefer* Department of Engineering Physics
Simulation Tool:
Results:
Conclusions:
A special thanks to the DoD High Energy Laser Joint Technology Office and USAF Research Lab
for funding support
LEEDR defines the well-mixed atmospheric boundary layer with a worldwide, probabilistic surface climatology according to season and time of day, then computes radiative transfer effects based on vertical profiles of interrelated variables including meteorological, aerosol, hydrometeor and optical turbulence.
• Probabilistic Extreme and Percentile Environmental Reference Tables (ExPERT) data for 573 land
sites; Surface Marine Gridded Climatology • 4D real-time and/or archived NWP now-cast / forecast and weather satellite data
0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6
x 10-5
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]
Pat
h R
adia
nce
[W c
m- 2
str- 1
µm
- 1]
Path Radiance200-K210-K220-K230-K240-K250-K260-K270-K280-K290-K300-K
0 0.05 0.1 0.15 0.2 0.250
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Dependent Variable(s)
Alti
tude
(m)
Molecular Absorption (1/km)Molecular Scattering (1/km)Aerosol Absorption (1/km)Aerosol Scattering (1/km)Total Extinction (1/km)
0 20 40 60 80 100 120 140 160 18010
-2
100
102
104
106
108
Phase Function Angle
Dep
ende
nt V
aria
ble(
s)
Mean Molecular ScatteringMean Aerosol ScatteringMean Clouds and Rain
6 8 10 12 14 16 18 20 22 240
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Microns
Pat
h T
rans
mitt
ance
(no
uni
ts)
Path Transmittance vs. Microns
LEEDR provides user multiple interactive views of atmospheric radiative effects
Raman LIDAR validates LEEDR’s unique profile of elevated aerosol effects which arise when aerosol radiative characteristics are correctly coupled to appropriate boundary layer lapse rates of temperature and dewpoint
• Coupling NWP and/or satellite weather data with climatologies enhance fundamental radiative transfer calculations (e.g. path radiance and refraction, optical turbulence)
• 4D-resolved optical turbulence and path refraction calculations will immediately benefit directed energy simulation tools (e.g. AFIT’s High Energy Laser Tactical Decision Aid) and applications (e.g. laser communication system design)
• Higher resolution path radiance solutions can benefit industry and Government remote EO/IR sensor capabilities
[email protected] [email protected] [email protected] [email protected]
LEEDR radiative transfer code augmented by:
*Applied Research Solutions, Inc. **Southwestern Ohio Council for Higher Education 50 Chestnut Suite, 240 3155 Research Blvd, Ste 204 Beavercreek OH 45440 USA Dayton OH 45420
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
500
1000
1500
2000
2500
3000
3500
4000
Dependent Variable(s)
Alti
tude
(m)
WPAFB, 25 Jul 13, 1400L, 355nm, T = 74F, Td = 56.5F, GADS, BL Height = 1250m, Vis = 60km
Experimental Particle Extinction, 0305 Local (1/km)Experimental Particle Extinction, 0820 Local (1/km)Experimental Particle Extinction, 1345 Local (1/km)LEEDR Aerosol Scattering (1/km)LEEDR Total Extinction (1/km)LEEDR Molecular Scattering (1/km)LEEDR Aerosol Absorption (1/km)LEEDR Molecular Absorption (1/km)
Path Radiance: A Relative Earth – Sun – Moon Geometry Calculation & Surface Albedos
Important for Solar/Lunar Calculations!
0.5 1 1.5 2 2.5 3
x 10-5
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]
Pat
h R
adia
nce
[W c
m- 2
str- 1
µm
- 1]
Path Radiance200-K210-K220-K230-K240-K250-K260-K270-K280-K290-K300-K
0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6
x 10-5
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]
Path
Rad
ianc
e [W
cm
- 2 s
tr- 1 µ
m- 1
]
Path Radiance200-K210-K220-K230-K240-K250-K260-K270-K280-K290-K300-K
3 4 5 6 7 8 9 10
x 10-7
0
1
2
3
4
5
6
7x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]
Path
Rad
ianc
e [W
cm
- 2 st
r- 1 µm
- 1]
0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6
x 10-5
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1x 10
-3 Path Radiance vs. Wavelength
Wavelength [m]
Pat
h R
adia
nce
[W c
m- 2
str- 1
µm
- 1]
200-K210-K220-K230-K240-K250-K260-K270-K280-K290-K300-KPlexus
0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
x 10-6
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
Tran
smis
sion
Transmission vs. Wavelength
Wavelength (m)
Path TransmittanceStraight Slant Path
Path TransmittancePoint-to-Point Refracted Path
Path TransmittanceDisplaced Refracted Path
0 1 2 3 4 5 6 7 8 9 10
x 104
200
400
600
800
1000
1200
Horizontal Distance (m)
Ver
tical
Dis
tanc
e (m
)
Point-to-Point Path: ExPERT vs NOMADS @ WPAFB 26 Jan 14Pltfm: 1m, Tgt: 2km, Path Length: 100km, Az: 270
EarthTarget AltitudePlatform AltitudeBent Laser: ExPERT 0600-0900LTargetPlatformStraight LaserBent Laser: NOMADS 1200Cycle/0700L
0 2 4 6 8 10 12 14 16
x 104
0
200
400
600
800
1000
1200
Horizontal Distance (m)
Ver
tical
Dis
tanc
e (m
)
Displaced Path: ExPERT vs NOMADS @ WPAFB 26 Jan 14Pltfm: 1m, Tgt: 2km, Path Length:100km, Az:270
EarthTarget AltitudePlatform AltitudeBent Laser: ExPERT 0600-0900LTargetPlatformStraight LaserBent Laser: NOMADS 1200 Cycle/0700L
Improved 4D atmospheric (and refractivity) resolution significantly effects accuracy of radiative transfer solutions: Comparison of cross-spectrum transmission for a straight 100 km (direct, point-to-point refracted and displaced refracted) path. The amount of refraction is varied 10 times across the spectral range shown.
http://nomads.ncdc.noaa.gov/data/gfs4/
Path Bending / Correction:
Accounting for Variation in the
Atmospheric Refractivity
Displaced Path Aim at endpoint, calculate laser path using path’s refractivity profile
Light Bending: Climatology vs Numerical Weather Data Displaced Path Point-to-Point ExPERT (climatology) miss distance: 64,185.1 m
NOMADS miss distance: 64,297.3 m ** NOMADS predicted a 112.2 m longer bent path length than climo **
Path refractivity profile based on 3 NOMADS atmospheric profiles (vs only 1 for ExPERT) to consider horizontal variations
NO
MA
DS
#1
NO
MA
DS
#2
NO
MA
DS
#3
Climo-derived AIRS-derived NWP-derived
Temperature
Climo-derived AIRS-derived NWP-derived Climo-derived AIRS-derived NWP-derived
Wind Speed Wind Direction
Dayton OH 12 Jan 2014, 18Z
Winds and Temperature Profiles: Climo-, Numerical Weather and Satellite
Climo-derived AIRS-derived NWP-derived
( )2
22 2 ( )( )( ) = (0.714) v nzz
z nzC C − ∂
∂∇
v
KH/KM - modified Tatarski
Optical Turbulence (cn2) Profiles: Climo-, Numerical Weather
and Satellite
Dayton OH 12 Jan 2014, 18Z
Applying
14 Oct 2011 0746Z, Dayton, OH
500
550
600
650
700
750
800
850
900
950
1000
0 50 100 150 200 250 300 350
Pres
sure
Lev
el (m
b)
Wind Direction
Satellite DataRAOB Data
500
550
600
650
700
750
800
850
900
950
1000
0 2 4 6 8 10 12 14 16 18 20
Pres
sure
Lev
el (m
b)
Wind Speed (m/s)
Satellite DataRAOB Data
10-22
10-20
10-18
10-16
10-14
0
5
10
15
20
25
30
35
40Vertical Cn2 Profile
Turbulence Structure (Cn2)
Hei
ght (
km)
Richardson Number and KH/KM ratio based on AIRS derived winds
Radiosonde Measured vs AIRS-derived Wind Profile
• Global coverage provides atmospheric vertical temperature profile (surface to 80km)
• Thermal wind relationship used to derive vertical wind profiles
• Vertical temperature and pressure profiles are used along with ∂Tv/∂Z and derived winds to calculate Cn
2 • Cn
2 profile calculated for each AIRS sounding location
Satellite-derived Optical Turbulence: Enhanced, global 4D resolution
Satellite-Derived vs Climo and Numerical Weather Data
Point to Point Calculate aimpoint solution which compensates for path refractivity and illuminate desired enpoint