GSFC STROZ Lidar at MOHAVE 2009 Laurence Twigg, Thomas J. McGee and Grant Sumnicht Code 613.3, Goddard Space Flight Center MOHAVE 2009 Water Vapor Workshop

GSFC STROZ Lidar at MOHAVE 2009GSFC STROZ Lidar at MOHAVE 2009

Laurence Twigg, Thomas J. McGee Laurence Twigg, Thomas J. McGee and Grant Sumnichtand Grant Sumnicht

Code 613.3, Goddard Space Flight Code 613.3, Goddard Space Flight CenterCenter

MOHAVE 2009 Water Vapor Workshop MOHAVE 2009 Water Vapor Workshop Bern, Switzerland, Oct. 18-21, 2010 Bern, Switzerland, Oct. 18-21, 2010 L. Twigg, et al.L. Twigg, et al.

Lidar Trailer at TMO for MOHAVE-2009Lidar Trailer at TMO for MOHAVE-2009

MOHAVE 2009 Water Vapor Workshop Bern, MOHAVE 2009 Water Vapor Workshop Bern, Switzerland, Oct. 18-21, 2010 Switzerland, Oct. 18-21, 2010 L. Twigg, et al.L. Twigg, et al.

STROZ-Lite NDACC Mobile LidarSTROZ-Lite NDACC Mobile Lidar

Originally Ozone, Aerosol and Temp instrumentOriginally Ozone, Aerosol and Temp instrument XeCl Excimer laser - 308 nmXeCl Excimer laser - 308 nm Nd-YAG laser @ 355 nmNd-YAG laser @ 355 nm 2004 - 408nm and 387 Lo channels added for water vapor 2004 - 408nm and 387 Lo channels added for water vapor

demonstration at MLOdemonstration at MLO 2005 – campaign at TMF – first comparisons with other 2005 – campaign at TMF – first comparisons with other

lidarlidar WAVES Campaign 2008WAVES Campaign 2008 2009 MOHAVE Campaign2009 MOHAVE Campaign


Significant Changes in Significant Changes in STROZ-Lite Mobile LidarSTROZ-Lite Mobile Lidar

(Between MOHAVE 2007 and MOHAVE 2009)(Between MOHAVE 2007 and MOHAVE 2009)

Change Spectra-Physics YAG for Continuum – higher power; Change Spectra-Physics YAG for Continuum – higher power; better polarization characteristicsbetter polarization characteristics

Excimer Laser had new pressure vessel installedExcimer Laser had new pressure vessel installed New PMT bases (Licel)New PMT bases (Licel) Mini Receiver for HMini Receiver for H22O channels – low altitude returnO channels – low altitude return Calibration LampCalibration Lamp AT lidar – new beam splitter (not tested during MOHAVE-AT lidar – new beam splitter (not tested during MOHAVE-

2009)2009)


STROZ NDACC Mobile LidarSTROZ NDACC Mobile LidarStatus during MOHAVE-2009Status during MOHAVE-2009

Major problems with laser systems (YAG and Excimer)Major problems with laser systems (YAG and Excimer) Continuous testing lead to many configuration changesContinuous testing lead to many configuration changes These changes included FOV settings, PMT changes as well These changes included FOV settings, PMT changes as well

as blocker filter use for H2O testas blocker filter use for H2O test By Last third of campaign achieved “stability” By Last third of campaign achieved “stability” T-O3 configurations alternated with 355 blocker filter use T-O3 configurations alternated with 355 blocker filter use

for H2O fluorescence testing. Thus time coincidences with for H2O fluorescence testing. Thus time coincidences with sonde launches were used for both O3 and H2O profile sonde launches were used for both O3 and H2O profile comparisons.comparisons.

AT lidar – similar problems led to only 1 night with 2 hrs of AT lidar – similar problems led to only 1 night with 2 hrs of engineering data, thus changes to test elimination of H2O engineering data, thus changes to test elimination of H2O fluorescence problem were never tested. fluorescence problem were never tested.


STROZ System ParametersSTROZ System Parameters


Parameter STROZ MOHAVE

STROZ Now

Laser Power 355) 9-10 W @ 50 Hz

15 W @ 50 HZ

Telescope Area 0.47 m**2 0.47 m**2

Field Of View * 1.0 mRad 0.7/2.3 mRad (fixed)

WV IF Bandwidth 1.0 nm 0.25 nm

Cal. Method Sonde Norm. Sonde Norm.

R. Error @ 10/50 ppm ~3-6% / ~2% ????

Low Alt Limit ~200 m AGL ~200 m AGL

* During MOHAVE, both the STROZ and the AT Lidar used an iris to provide a variable Field of View. These are the calculated FOV used for WV measurements based on a measurement of the iris diameter at the various détentes. Recent data indicate that this introduces errors. New fixed apertures installed

STROZ-Lite –TMF-2005 CalibrationSTROZ-Lite –TMF-2005 Calibration

STROZSTROZ Lidar calibrated against Lidar calibrated against

local, synchronous RS-92 local, synchronous RS-92 launcheslaunches

Calibration constant Calibration constant determined determined between between 2 – 3 km above lidar2 – 3 km above lidar

If sharp features were If sharp features were noted, a different range was noted, a different range was selectedselected

STROZ H2O Measurements STROZ H2O Measurements at 2.3 mRad FOVat 2.3 mRad FOV

STROZ Hi-Pair Calibration ConstantSTROZ Hi-Pair Calibration ConstantMean = 217.1 SD = 14.4 (6.6%)Mean = 217.1 SD = 14.4 (6.6%)


Day #6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0

Cal

ibra

tion

Con

stan

t

150

200

250

300

STROZ-Lite MOHAVE-2009STROZ-Lite MOHAVE-2009 Calibration Factors Calibration Factors

STROZSTROZ During MOHAVE-2009, The During MOHAVE-2009, The

STROZ lidar operated in two STROZ lidar operated in two modes – the Ozone Mode modes – the Ozone Mode with FOV 2.3; and the Water with FOV 2.3; and the Water vapor mode – FOV 1.0vapor mode – FOV 1.0

The Mean value of the Lo-The Mean value of the Lo-Pair Cal Factor was 13.3 +/- Pair Cal Factor was 13.3 +/- 9%, which leads to a value 9%, which leads to a value for the Hi-Pair Cal Factor of for the Hi-Pair Cal Factor of 215 +/- 5%215 +/- 5%

Compare this with the Compare this with the MOHAVE-2005 value of 217 MOHAVE-2005 value of 217 +/- 7+/- 7


Fluorescence in STROZ WVFluorescence in STROZ WV


October 20/21, 2009

STROZ-Lite vs. RS92-Corr. SondeSTROZ-Lite vs. RS92-Corr. Sonde

BlockedBlocked UnblockedUnblocked


STROZ-Lite vs. CFHSTROZ-Lite vs. CFHBlockedBlocked UnblockedUnblocked


STROZ vs. JPL-WVSTROZ vs. JPL-WVUnblockedUnblockedBlockedBlocked


STROZ-Lite vs. ALVICESTROZ-Lite vs. ALVICEBlockedBlocked UnblockedUnblocked


Issues Noted during MOHAVE and Later TestsIssues Noted during MOHAVE and Later Tests

One PMT showed long term increase in output with “constant” One PMT showed long term increase in output with “constant” signal – needed to replace PMT but not base – Not a WV channelsignal – needed to replace PMT but not base – Not a WV channel

All channels in the AT system are apparently not aligned the same All channels in the AT system are apparently not aligned the same – showed up in changing ratios with change in FOV– showed up in changing ratios with change in FOV

Changing the AT FOV was not repeatableChanging the AT FOV was not repeatable– Detents not “kinematic”Detents not “kinematic”– Vanes in iris may stickVanes in iris may stick

A constant signal does not give the same number of counts in A constant signal does not give the same number of counts in different Licel photon counting modulesdifferent Licel photon counting modules– Cal lamp signal into one channel was moved from one counter to another Cal lamp signal into one channel was moved from one counter to another – All PMT parameters kept the sameAll PMT parameters kept the same– The same discriminator setting was used for all countersThe same discriminator setting was used for all counters


AT and STROZ-Lite H2O profilesAT and STROZ-Lite H2O profilesGSFC on 10/8/2010 – 2 Hr AveragesGSFC on 10/8/2010 – 2 Hr Averages


H2O SummaryH2O Summary

Comparison of blocked vs. unblocked STROZ-Lite H2O profiles during Comparison of blocked vs. unblocked STROZ-Lite H2O profiles during MOHAVE-2009 show effects consistent with fluorescence.MOHAVE-2009 show effects consistent with fluorescence.

Effect seen in comparisons vs. sondes and other lidar systems.Effect seen in comparisons vs. sondes and other lidar systems. New observations obtained after modifications applied to both AT and New observations obtained after modifications applied to both AT and

STROZ systems show current H2O profiles for both blocked and STROZ systems show current H2O profiles for both blocked and unblocked observation modes yield the same result! unblocked observation modes yield the same result!

However – this is still not proof that ALL fluorescence has been However – this is still not proof that ALL fluorescence has been eliminated (could different telescope mirrors/coatings be giving the eliminated (could different telescope mirrors/coatings be giving the same effect???).same effect???).

Thus there is a need for a new (TMO) campaign to acquire long Thus there is a need for a new (TMO) campaign to acquire long integrations at a dark site (no moon) in order to see if any fluorescence integrations at a dark site (no moon) in order to see if any fluorescence still exists in either mobile lidar system.still exists in either mobile lidar system.

Need to further examine roles of smoothing window, background Need to further examine roles of smoothing window, background definition, residual fluorescence on H2O profiles.definition, residual fluorescence on H2O profiles.

Use corrected RS92 sondes???Use corrected RS92 sondes??? Add “Blocked” or “Unblocked” to 60 min files.Add “Blocked” or “Unblocked” to 60 min files.


STROZ-Lite Temperature Profiles during STROZ-Lite Temperature Profiles during MOHAVE 2009MOHAVE 2009

Same observational issues as with H2O, i.e. configuration Same observational issues as with H2O, i.e. configuration changes, sonde launch time coincidences, etc.changes, sonde launch time coincidences, etc.

Reminder - changes included FOV settings, PMT changes Reminder - changes included FOV settings, PMT changes as well as blocker filter use for H2O testas well as blocker filter use for H2O test

Last 5 days of campaign – always acquired 2 hr of T-O3 Last 5 days of campaign – always acquired 2 hr of T-O3 data using large (2.3 mrad) FOVdata using large (2.3 mrad) FOV

Reminder – no AT lidar temperature profiles – various Reminder – no AT lidar temperature profiles – various system problems led to only 1 night with 2 hrs of system problems led to only 1 night with 2 hrs of engineering dataengineering data


STROZ-Lite vs. RS92_Corr. SondeSTROZ-Lite vs. RS92_Corr. Sonde


STROZ-Lite vs. CFHSTROZ-Lite vs. CFH


STROZ-Lite vs. FPHSTROZ-Lite vs. FPH


STROZ-Lite Vs. JPL TemperatureSTROZ-Lite Vs. JPL Temperature


STROZ-Lite vs. ALVICE TemperatureSTROZ-Lite vs. ALVICE Temperature


Temperature SummaryTemperature Summary

Good agreement with sondes and other Good agreement with sondes and other lidar systems. lidar systems.

Some comparisons show ~1-2 cold bias at Some comparisons show ~1-2 cold bias at 15-20 kms15-20 kms

Limited T data – longer campaign usefulLimited T data – longer campaign useful Algorithm changes – time to re-run Algorithm changes – time to re-run

Thierry’s simulation program???Thierry’s simulation program???


STROZ OSTROZ O33 at MOHAVE 2009 at MOHAVE 2009

Ozone Comparisons were made with ECC sondes, Ozone Comparisons were made with ECC sondes, and the JPL Stratospheric and Tropospheric lidarsand the JPL Stratospheric and Tropospheric lidars

STROZ lidar had new PMT housings and in one STROZ lidar had new PMT housings and in one case a completely new photomultiplier tube case a completely new photomultiplier tube installed for ozone measurements.installed for ozone measurements.

Not all ozone measurements were simultaneous Not all ozone measurements were simultaneous with sonde launches due to water vapor with sonde launches due to water vapor measurement constraints and/or system measurement constraints and/or system configuration changes.configuration changes.


STROZ vs JPL LidarsSTROZ vs JPL Lidars

Nine nights of comparable lidar Nine nights of comparable lidar measurementsmeasurements

Good agreement from 15 to 45 Good agreement from 15 to 45 km between STROZ and JPL km between STROZ and JPL Stratospheric LidarStratospheric Lidar

Agreement is not as good below Agreement is not as good below 15 km, especially between STROZ 15 km, especially between STROZ and the JPL Trop Ozone lidar – and the JPL Trop Ozone lidar – believed to be related to the need believed to be related to the need to amplify the 308 signals to amplify the 308 signals

Noise in STROZ profile above 45 Noise in STROZ profile above 45 km also due to weak 308 signals – km also due to weak 308 signals – this is an electronic issue not a this is an electronic issue not a laser power issuelaser power issue


STROZ FPH Ozone ComparisonsSTROZ FPH Ozone Comparisons

3 comparable FPH launches 3 comparable FPH launches with ECC sondeswith ECC sondes

Ascent data used for Ascent data used for comparisonscomparisons

Reasonable agreement from Reasonable agreement from 13 km to 27 km (mean 13 km to 27 km (mean difference = -3.4%)difference = -3.4%)


STROZ CFH Ozone ComparisonsSTROZ CFH Ozone Comparisons

5 comparable CFH 5 comparable CFH launches with ECC sondes launches with ECC sondes during MOHAVEduring MOHAVE

Reasonable agreement Reasonable agreement between 15 and 30 KM – between 15 and 30 KM – Mean diff = 1.20+/- 1.13Mean diff = 1.20+/- 1.13

pump correction errors pump correction errors above 30 km?above 30 km?


Conclusions and SolutionsConclusions and Solutions

A fixed field stop is necessary – the errors introduced from an A fixed field stop is necessary – the errors introduced from an uncertain aperture size convolved with slight differences in uncertain aperture size convolved with slight differences in alignment at different channels are too large. alignment at different channels are too large. SOLUTION:SOLUTION: Kinematic mounts to allow for interchangeable, fixed apertures Kinematic mounts to allow for interchangeable, fixed apertures fabricated and installed in both STROZ and AT lidars. fabricated and installed in both STROZ and AT lidars.

Fluorescence is an issue within the STROZ lidar. Fluorescence is an issue within the STROZ lidar. SOLUTION: SOLUTION: Field Field lens and collimating lens assembly were fabricated from lens and collimating lens assembly were fabricated from extremely low fluorescence fused silica – received and installed in extremely low fluorescence fused silica – received and installed in STROZ.; may not be necessary for AT STROZ.; may not be necessary for AT

Changing or swapping Licel cards changes the calibration – input Changing or swapping Licel cards changes the calibration – input pre-amplifier issues?pre-amplifier issues?

All of these needed changes were implemented as of Oct 2010All of these needed changes were implemented as of Oct 2010


Conclusions and SolutionsConclusions and Solutions(Continued)(Continued)

H20 looks much better, but needs more observations for H20 looks much better, but needs more observations for verificationverification

O3 looks good above 15 km. Tests indicate that O3 looks good above 15 km. Tests indicate that amplification of 308 signals may improve sensitivity below amplification of 308 signals may improve sensitivity below 15 km15 km

Testing underway for limitations of O3 using 0.7 mrad Testing underway for limitations of O3 using 0.7 mrad aperture (excimer divergence problems)aperture (excimer divergence problems)

T looks to be ~ 1degree cool on average, BUT night-to-night T looks to be ~ 1degree cool on average, BUT night-to-night changes in magnitude – smoothing, DTC issues??? changes in magnitude – smoothing, DTC issues???


Documents

GSFC STROZ Lidar at MOHAVE 2009 Laurence Twigg, Thomas J. McGee and Grant Sumnicht Code 613.3, Goddard Space Flight Center MOHAVE 2009 Water Vapor Workshop