NASA Technical Reports Server (NTRS) 20160005969: Atmospheric CO2 Column Measurements from Laser Absorption Lidar Systems

4.5 MB·English

by  NASA Technical Reports Server (NTRS)

Atmospheric CO Column
2
Measurements from
Laser Absorption Lidar Systems
Bing Lin1, Syed Ismail1, F. Wallace Harrison1, Edward
Browell2, Amin Nehrir1, Jeremy Dobler3, Byron Meadows1,
Michael Obland1, Susan Kooi4, Tai-Fang Fan4, and
LaRC ASCENDS team
1NASA Langley Research Center, Hampton, Virginia
2STARSS II Affiliate, Hampton, Virginia
3Exelis Inc., Ft. Wayne, IN
4Science System and Application, Inc, Hampton, VA
95th AMS Annual Meeting
Phoenix, AZ, 4-8 January 2015
Outline
 Introduction
o Atmospheric CO : missing CO ?
2 2
o Observational challenges
o Approach: active sensing & IPDA
 Instrument development
o System design
o Capability: ranging & cloud discrimination
 Measurement Results
o Flight campaigns
o Validation
 Modeling Efforts
o Improving instrument and space application
 Summary
Annual CO Budget & Variation
2
Terrestrial sink: residual >>> large errors
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Land plants and ocean uptake removes some of atmospheric CO
2
Atmosphere CO budgets: large variations
2
Prediction of this trend and variability, especially in changing climate (?)
Atmospheric CO Measurements
2
Grand Challenge!
Midwest Flights
Flight 6, 10 August 2011
B
A
Flight 7, 11 August 2011
10-s CO Mea.
2
from 4600 m AGL
• CO uptake observed
2
over corn fields in E. ~10 ppm CO
2
column difference
Nebraska & Iowa.
• Higher CO observed
2
over Colorado & W.
Nebraska.
A B
Omaha
• Enhanced CO found in
2
vicinity of Omaha.
Measurement Architecture
o Simultaneously transmits l and l >>> reducing noise from the
on off
atmosphere, solar radiation, and surface reflectivity
o Separate systems for CO (1.57 mm) & O (1.26 mm) measurements >>>
2 2
deriving XCO using coincident CO & O column measurements
2 2 2
o IM laser wavelengths with unique waveforms >>> range estimation and
cloud discrimination (analogous to CW radar and GPS system)
Intensity Encoding for Ranging and
Cloud/Aerosol Discrimination
l l l
l l l
11 22 33 • Each wavelength encoded with

cloud returns! a unique modulation waveform.
• Received IM signals experience
!
R
certain time delays before
,
e
g
n reaching the receiver.
a
R
• Matched filter is listening and
surface return!
finds the expected waveforms at
!
S the time delay corresponding to
MMoodduulalatitoion nS isginganl a l S SSccactaatettrttieenrrgiin nPggr oP fiprloreo,f Aiflie(lRe A) !((RR)) M C oa r t rc e l haLteioodcn k/fLi-loitneck rO- ionu utOptuupttup ut t !
range, R.
Railroad Valley, NV, 3 August 2011
Surface Returns (with
cloud attenuation)
Cirrus Cloud
R
a Returns
n
g
e

Cloud
Surface Returns
Returns e
g
n
a
R
Time Time
TimTiem(cid:9)eh hisisttoorryy (cid:9)oof fo(cid:9)onlnin-el imneat(cid:9)clohecdk f-iilnte(cid:9)ro ouuttppuutts.(cid:9)(cid:9) IntInetnenssitityy(cid:9) mmaapp o(cid:9)fo mf(cid:9)alotcchked-i nfil(cid:9)toeru otuptuputt.(cid:9)(cid:9)
(cid:9) (cid:9)
(cid:9) (cid:9)
(cid:9) (cid:9)
Instrument and Algorithm
Development
ASCENDS CarbonHawk
Multifunctional Fiber Laser Lidar
Experiment Simulator (ACES)
(MFLL)
O lidar
2
500KHz BW; 2 MHz sampling rate
CO lidar
2
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
fixed freq rolling tone swept freq pseudo noise
Instrument Development
(in collaboration with Exelis)
ASCENDS CarbonHawk
Experiment Simulator
(ACES developed at LaRC
with support from Exelis)
Multifunctional Fiber
Laser Lidar (MFLL)
(developed by Exelis in 2004
Exelis and Langley since 2005)
310W amplifier
integration
advancing key technologies
for spaceborne measurements
of CO column mixing ratio
2
Instrument-aircraft integration
Development and demonstration of MFLL
various
lab,
ground
range,
and
flight
tests
Finished all data processing of flight measurements!
2010 ASCENDS DC-8 Campaign, 6-18 July
3-RRV/
GOSAT
1-Veg
5-DOE
Eng Flt
ARM/
TCCON
4-Ocean
2-Desert
Surface Reflectances & CO Measurement Precision (7-km AGL)
2
Surfaces Desert Desert Vegetation Vegetation Ocean
Location Railroad Needles, CA Central DOE ARM, Pacific off Baja
Valley, NV Valley, CA Lamont, OK
Median Surface 0.143 0.118 0.098 0.080 0.03-0.06
Reflectance [sr-1]
1-s CO SNR 630 612 545 560 ~186
2
(0.59) (0.59) (0.68) (0.65) (2.07)
(CO [ppmv])
2
10-s CO SNR 1347 1443 1236 1460 ~531
2
(0.27) (0.25) (0.30) (0.25) (0.72)
(CO [ppmv])
2