Doppler Wind and Temperature Sounder: A breakthrough technique GATS Proprietary Larry Gordley, GATS Inc. Dave Fritts, GATS Inc. Tom Marshall, GATS Inc. COSPAR Scientific Assembly 2012 Mysore, India

DWTS Instrument Overview Specifications: Mass – 8 kg Power – 12 W Volume ~36x23x22 cm Data rate < 30 kbps with low alt wind Three 5.0 cm aperture thermal IR cameras NO (hi alt) 1829 – 1873 wn 13 CO 2 (mid alt) 2258 – 2282 wn, N 2 O (for low alt wind) 2120 – 2160 wn Static limb viewing, 20° FOV at velocity normal T, V, N 2 O and 13 CO 2 mixing ratios, VER (NO and CO 2 ) Single telescope two-channel design above, has evolved to three independent cameras, below. GATS Proprietary

Temperature Measures Low Pressure Doppler Broadened Emission Line Width is proportional to square root of kinetic temperature

ν (wavenumber, frequency) Single Atmospheric Emission line 1 Emission lines are typically a few thousandths of a wavenumber wide, requiring optical resolving powers of 100,000 or more to measure. Typically, good spectrometers achieve 10,000. DWTS achieves >300,000. GATS Proprietary

Doppler Shift Measurements Broadband emission will not detect Doppler shift, nor will spectra measurements, unless there is a zero shift reference

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity shift, Δν ν (wavenumber, frequency) signal Atmospheric spectral emission from one line 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity Atmospheric spectral emission from one line 1 signal shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity Atmospheric spectral emission from one line signal 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Doppler Spectral shift due to line-of-sight (LOS) relative air velocity signal Atmospheric spectral emission from one line shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

A Gas Filter Reference DWTS “Notch” filter Approach By viewing through a sample of the emitting gas, a filter is produced that causes a drop in signal during the Doppler Integration Pass (DIP) through the zero shift position

1 Add Gas Cell – One Emission Line Example. Gas cell acts as high resolution notch filter and effectively serves as the zero shift reference point. The “shift, Δν ” is the spectral separation of the cell spectra (black absorption feature) from the observed atmospheric spectra (red emission feature). signal Cell Absorption and Atmospheric Emission shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

1 Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

2 Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

1 Add Gas Cell – One Emission Line Example Cell Absorption and Atmospheric Emission signal shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary

1 Add Gas Cell – One Emission Line Example Cell Absorption and Atmospheric Emission 1 signal shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary

Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary 1

Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary 1

2 Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary 1 1

Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary 1

Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary 1

1 Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary

1 Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary

1 Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary

1 Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary

1 Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission 1 shift, Δν ν (wavenumber, frequency) 0 Δν GATS Proprietary

1 Add Gas Cell – One Emission Line Example signal Cell Absorption and Atmospheric Emission DIP width is proportional to square root of cell temperature + atmospheric temperature shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Multi-line Effect The emission lines that match the corresponding cell gas lines (i.e. “notch” filters), are scanned simultaneously, producing a DIP signal consistent with the total multi-line emission. The DIP width is the same as the single line DIP.

Two Line Example Cell Absorption & Atmospheric Emission, two lines 1 21 signal shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary 2

Two Line Example signal Cell Absorption & Atmospheric Emission, two lines shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Two Line Example signal 21 Cell Absorption & Atmospheric Emission, two lines shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary 2 1

Two Line Example signal Cell Absorption & Atmospheric Emission, two lines shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Two Line Example signal 21 Cell Absorption & Atmospheric Emission, two lines shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary 1 2

Two Line Example signal Cell Absorption & Atmospheric Emission, two lines shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Two Line Example signal Cell Absorption & Atmospheric Emission, two lines shift, Δν ν (wavenumber, frequency) 0 GATS Proprietary

Orbit Implementation By imaging the limb, normal to the spacecraft (SC) velocity vector, air parcels at all altitudes will produce a DIP signal as they traverse the FOV (i.e the 2D detector array). The animation tracks just one exaggerated Limb Air Volume (LAV).

Cell Absorption & Atmospheric Emission, two lines signal y x Altitude Δν (wavenumber) shift DWTS FOV Imaged on 2D Detector FPA z -10°+10° 0° Angle from Velocity Normal Relative Air Velocity due to SC SC Velocity Limb Air Volume (LAV) viewed from above Limb Air Volume (LAV) Implementation, In-Orbit Observations Observations Through Limb Atmospheric Volume Above, Spectra and Signal from one LAV Figures below depict observation geometry Observation Vectors shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary LAV

signal Cell Absorption & Atmospheric Emission, two lines y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity Limb Air Volume (LAV) In-Orbit Observations Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

signal Cell Absorption & Atmospheric Emission, two lines 21 y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity Limb Air Volume (LAV) In-Orbit Observations Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary 1 2

signal Cell Absorption & Atmospheric Emission, two lines 21 y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity Limb Air Volume (LAV) In-Orbit Observations Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

signal Cell Absorption & Atmospheric Emission, two lines 21 y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity Limb Air Volume (LAV) In-Orbit Observations Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary 1 2

signal Cell Absorption & Atmospheric Emission, two lines y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity Limb Air Volume (LAV) In-Orbit Observations Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

signal Cell Absorption & Atmospheric Emission, two lines y x Altitude Δν (wavenumber) shift z -10°+10° 0° SC Velocity Relative Air Velocity due to SC Limb Air Volume (LAV) 140 different observation angles during pass through FOV 140 shift observations as LAV passes through FOV In-Orbit Observations Angle from Velocity Normal (140 observations across FOV) Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

LOS Wind Finite Line-of-Sight (LOS) wind will change the zero shift position. The zero shift position for zero wind is known to ± <0.1 m/s due to knowledge of SC velocity (± <<1m/s) and attitude (± <3 arcsec). Also, precise attitude knowledge permits statistical calibration in orbit.

signal Cell Absorption & Atmospheric Emission, two lines y x Altitude Δν (wavenumber) shift z -10°+10° 0° SC Velocity Relative Air Velocity due to SC Limb Air Volume (LAV) with ≅ 250 m/s LOS wind 2° Apparent zero relative air speed (shift) with ≅ 250 m/s LOS wind Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors In-Orbit Observations – LOS Wind Effect DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

The “Shift/Angle” Scale Spectrally close lines (such as Lambda doublets for nitric oxide) provide the measure of “shift/angle” scale. The observed angle separating doublet DIP features is proportional to relative AT air speed, which is proportional to SC velocity plus AT wind.

y x Altitude Δν (wavenumber) shift z -10°+10° 0° 2 1 Relative Air Velocity due to SC SC Velocity signal Doublet Example 1 Limb Air Volume (LAV) Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above In-Orbit Observations - Doublet Effect shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

y x Altitude Δν (wavenumber) shift z -10°+10° 0° 1 Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle 1 GATS Proprietary 2

y x Altitude Δν (wavenumber) shift z -10°+10° 0° 1 Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle 1 GATS Proprietary 2

y x Altitude Δν (wavenumber) shift z -10°+10° 0° 1 Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle 1 GATS Proprietary 2

y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle 12 GATS Proprietary 1 2

y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle 12 GATS Proprietary 1 2

y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle 12 GATS Proprietary 1 2

y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

y x Altitude Δν (wavenumber) shift z -10°+10° 0° signal SC Velocity Relative Air Velocity due to SC Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

y x Altitude Δν (wavenumber) shift z -10°+10° 0° 2 Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle 2 GATS Proprietary 1

y x Altitude z -10°+10° 0° 2 Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle 2 GATS Proprietary 1

y x Altitude Δν (wavenumber) shift z -10°+10° 0° 2 Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle 2 GATS Proprietary 1

y x Altitude Δν (wavenumber) shift z -10°+10° 0° Relative Air Velocity due to SC SC Velocity signal Doublet Example Limb Air Volume (LAV) Doublet Effect Angle from Velocity Normal Observation Vectors Observations Through Limb Atmospheric Volume DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above shift, Δν ν (wavenumber, frequency) 0 Observation Angle GATS Proprietary

AT Wind Measurement The AT wind stretches or contracts the “shift/angle” scale, providing the AT wind estimate.

y x Altitude Δν (wavenumber) shift ν (wavenumber, frequency) z -10°+10° Doublet Example 0° shift, Δν signal SC Velocity In-Orbit Observations - Along Track (AT) Wind Effect AT = 0 m/s Relative Air Velocity due to SC Limb Air Volume (LAV) AT ≅ 700 m/s (AT same direction as SC) Angle from Velocity Normal Observations Through Limb Atmospheric Volume Observation Vectors DWTS FOV Imaged on 2D Detector FPA Limb Air Volume (LAV) viewed from above 0 Observation Angle GATS Proprietary

Current Measurement Systems GATS Proprietary

Current Measurement Systems T, W2 T, W1 W1 None D 15 km km N T = Temperature, W1 – One Vector Wind, W2 – Two Vector Wind Day Night Typically a narrow slit, observing at a 45° degree angle to the spacecraft velocity vector, creates a spectrum that is used to deduce LOS Wind. The slit observations are averaged from 150 km to sometimes over 700 km to obtain required S/N, producing an average wind over those same along-track distances. Altitude range of current technology products 150 km to 700 km GATS Proprietary

DWTS Measurement Systems GATS Proprietary

DWTS Measurement System As the atmospheric limb air passes through the DWTS FOV, it is observed with 10 km resolution and at 140 different Doppler shifts. This provides the information necessary to infer profiles of wind and temperature (depicted by colored air emerging from the FOV) at a 7 km along-track spacing with a 10 km along-track resolution. The FOV acts as an assembly line that produces a wind and temperature product for narrow air volumes. T = Temperature, W1 – One Vector Wind, W2 – Two Vector Wind Altitude range of DWTS products T, W2 T, W1 W1 None DN 15 km km -10°+10° DWTS FOV 1000 km 0° Day Night Processed Profiles are Spaced at 7 km with 10km along-track resolution GATS Proprietary

Summary DWTS uses Gas Filter Correlation Radiometry and a simple, moderately cooled, static MIR camera to measure Wind and Temperature from cloud-top to over 200 km day and night. Considering cost, global coverage, continuity, spatial resolution, diurnal capability, altitude range and simultaneity of Wind and Temperature, DWTS is projected to advance our capability of remotely sensing upper atmosphere wind and temperature by more than 3 orders of magnitude.

GATS Inc Canon Blvd., Suite 101 Newport News, VA USA GATS Proprietary Larry Gordley Dave Fritts Tom Marshall Doppler wind and temperature sounder: new approach using gas filter radiometry Larry L. Gordley and Benjamin T. Marshall, “Doppler wind and temperature sounder: new approach using gas filter radiometry”, J. Appl. Remote Sens. 5, (2011)