Ground-based water vapor Raman lidar measurements up to the upper troposphere and lower stratosphere – Part 2: Data analysis and calibration for long-term monitoring

Abstract. The well-recognized, key role of water vapor in the upper troposphere and lower stratosphere (UT/LS) and the scarcity of high-quality, long-term measurements triggered the development by JPL of a powerful Raman lidar to try to meet these needs. This development started in 2005 and was endorsed by the Network for the Detection of Atmospheric Composition Change (NDACC) and the validation program for the EOS-Aura satellite. In this paper we review all the stages of the instrument data acquisition, data analysis, profile retrieval and calibration procedures, as well as selected results from the recent validation campaign MOHAVE-2009 (Measurements of Humidity in the Atmosphere and Validation Experiments). The stages in the instrumental development and the conclusions from three validation campaigns (including MOHAVE-2009) are presented in details in a companion paper (McDermid et al., 2011). In its current configuration, the lidar demonstrated capability to measure water vapor profiles from ~1 km above the ground to the lower stratosphere with an estimated accuracy of 5 %. Since 2005, nearly 1000 profiles have been routinely measured with a precision of 10 % or better near 13 km. Since 2009, the profiles have typically reached 14 km for 1 h integration times and 1.5 km vertical resolution, and can reach 21 km for 6-h integration times using degraded vertical resolutions.

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Ground-based water vapor Raman lidar measurements up to the upper troposphere and lower stratosphere – Part 1: Instrument development, optimization, and validation

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-4-5079-2011 ◽

2011 ◽

Vol 4 (4) ◽

pp. 5079-5109 ◽

Cited By ~ 4

Author(s):

I. S. McDermid ◽

T. Leblanc ◽

T. D. Walsh

Keyword(s):

Water Vapor ◽

Lower Stratosphere ◽

Companion Paper ◽

Atmospheric Composition ◽

Raman Lidar ◽

Upper Troposphere ◽

Lidar Measurements ◽

Instrumental Development ◽

Validation Experiments

Abstract. Recognizing the importance of water vapor in the upper troposphere and lower stratosphere (UT/LS) and the scarcity of high-quality, long-term measurements, JPL began the development of a powerful Raman lidar in 2005 to try to meet these needs. This development was endorsed by the Network for the Detection of Atmospheric Composition Change (NDACC) and the validation program for the EOS-Aura satellite. In this paper we review the stages in the instrumental development of the lidar and the conclusions from three validation campaigns: MOHAVE, MOHAVE-II, and MOHAVE 2009 (Measurements of Humidity in the Atmosphere and Validation Experiments). The data analysis, profile retrieval and calibration procedures, as well as additional results from MOHAVE-2009 are presented in detail in a companion paper (Leblanc et al., 2011a). Ultimately the lidar has demonstrated capability to measure water vapor profiles from ~1 km above the ground to the lower stratosphere, reaching 14 km for 1-h integrated profiles and 21 km for 6-h integrated profiles, with a precision of 10 % or better near 13 km and below, and an estimated accuracy of 5 %.

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Ground-based water vapor raman lidar measurements up to the upper troposphere and lower stratosphere for long-term monitoring

Atmospheric Measurement Techniques ◽

10.5194/amt-5-17-2012 ◽

2012 ◽

Vol 5 (1) ◽

pp. 17-36 ◽

Cited By ~ 43

Author(s):

T. Leblanc ◽

I. S. McDermid ◽

T. D. Walsh

Keyword(s):

Water Vapor ◽

Lower Stratosphere ◽

Lower Troposphere ◽

Atmospheric Composition ◽

Raman Lidar ◽

Upper Troposphere ◽

Lidar Measurements ◽

Development Data ◽

Instrumental Development

Abstract. Recognizing the importance of water vapor in the upper troposphere and lower stratosphere (UTLS) and the scarcity of high-quality, long-term measurements, JPL began the development of a powerful Raman lidar in 2005 to try to meet these needs. This development was endorsed by the Network for the Detection of Atmospheric Composition Change (NDACC) and the validation program for the EOS-Aura satellite. In this paper we review the stages in the instrumental development, data acquisition and analysis, profile retrieval and calibration procedures of the lidar, as well as selected results from three validation campaigns: MOHAVE (Measurements of Humidity in the Atmosphere and Validation Experiments), MOHAVE-II, and MOHAVE 2009. In particular, one critical result from this latest campaign is the very good agreement (well below the reported uncertainties) observed between the lidar and the Cryogenic Frost-Point Hygrometer in the entire lidar range 3–20 km, with a mean bias not exceeding 2% (lidar dry) in the lower troposphere, and 3% (lidar moist) in the UTLS. Ultimately the lidar has demonstrated capability to measure water vapor profiles from ∼1 km above the ground to the lower stratosphere with a precision of 10% or better near 13 km and below, and an estimated accuracy of 5%. Since 2005, nearly 1000 profiles have been routinely measured, and since 2009, the profiles have typically reached 14 km for one-hour integration times and 1.5 km vertical resolution, and can reach 21 km for 6-h integration times using degraded vertical resolutions. These performance figures show that, with our present target of routinely running our lidar two hours per night, 4 nights per week, we can achieve measurements with a precision in the UTLS equivalent to that achieved if launching one CFH per month.

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A Raman lidar at La Reunion (20.8° S, 55.5° E) for monitoring water vapor and cirrus distributions in the subtropical upper troposphere: preliminary analyses and description of a future system

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-4-6449-2011 ◽

2011 ◽

Vol 4 (5) ◽

pp. 6449-6496

Author(s):

C. Hoareau ◽

P. Keckhut ◽

J.-L. Baray ◽

L. Robert ◽

Y. Courcoux ◽

...

Keyword(s):

Water Vapor ◽

Cirrus Cloud ◽

La Réunion ◽

Raman Lidar ◽

Data Set ◽

Upper Troposphere ◽

Future System ◽

Rayleigh Lidar ◽

Term Monitoring

Abstract. A ground based Rayleigh lidar has provided continuous observations of tropospheric water vapor profiles and cirrus cloud using a preliminary Raman channels setup on an existing Rayleigh lidar above La Reunion over the period 2002–2005. With this instrument, we performed a first measurement campaign of 350 independent water vapor profiles. A statistical study of the distribution of water vapor profiles is presented and some investigations concerning the calibration are discussed. The data set having several long acquisition measurements during nighttime, an analysis of the diurnal cycle of water vapor has also been investigated. Analysis regarding the cirrus clouds is presented and a classification has been performed showing 3 distinct classes. Based on these results, the characteristics and the design of a future lidar system to be implemented at the new Reunion Island altitude observatory (2200 m) for long-term monitoring is presented and numerical simulations of system performance have been realized to compare both instruments.

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Methodology for Water Monitoring in the Upper Troposphere with Raman Lidar at the Haute-Provence Observatory

Journal of Atmospheric and Oceanic Technology ◽

10.1175/2009jtecha1287.1 ◽

2009 ◽

Vol 26 (10) ◽

pp. 2149-2160 ◽

Cited By ~ 18

Author(s):

Christophe Hoareau ◽

Philippe Keckhut ◽

Alain Sarkissian ◽

Jean-Luc Baray ◽

Georges Durry

Keyword(s):

Water Vapor ◽

Time Integration ◽

Raman Lidar ◽

Total Water ◽

Upper Troposphere ◽

Clear Sky ◽

Term Evolution ◽

Calibration Methods ◽

Calibration Techniques

Abstract A Raman water vapor lidar has been developed at the Haute-Provence Observatory to study the distribution of water in the upper troposphere and its long-term evolution. Some investigations have been proposed and described to ensure a pertinent monitoring of water vapor in the upper troposphere. A new method to take into account the geophysical variability for time integration processes has been developed based on the stationarity of water vapor. Successive measurements, considered as independent, have been used to retrieve H2O profiles that were recorded during the same nighttimes over a few hours. Various calibration methods, including zenith clear-sky observation, standard meteorological radiosondes, and total water vapor column, have been investigated. A method to evaluate these calibration techniques has been proposed based on the variance weakening. For the lidar at the Haute-Provence Observatory, the calibration based on the total water vapor column appears to be the optimum method. Radiosondes also give comparable results, but do not allow lidar to be independent. The clear-sky zenith observation is an original technique, and seems to accurately identify discontinuities. However, it appears to be less reliable, based on the variance investigation, than the two others. It is also sensitive to aerosol loading, which is also expected to vary with time.

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The need for accurate long‐term measurements of water vapor in the upper troposphere and lower stratosphere with global coverage

Earth s Future ◽

10.1002/2015ef000321 ◽

2016 ◽

Vol 4 (2) ◽

pp. 25-32 ◽

Cited By ~ 14

Author(s):

Rolf Müller ◽

Anne Kunz ◽

Dale F. Hurst ◽

Christian Rolf ◽

Martina Krämer ◽

...

Keyword(s):

Water Vapor ◽

Lower Stratosphere ◽

Upper Troposphere ◽

Global Coverage

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Correction technique for Raman water vapor lidar signal-dependent bias and suitability for water vapor trend monitoring in the upper troposphere

Atmospheric Measurement Techniques ◽

10.5194/amt-5-2893-2012 ◽

2012 ◽

Vol 5 (11) ◽

pp. 2893-2916 ◽

Cited By ~ 19

Author(s):

D. N. Whiteman ◽

M. Cadirola ◽

D. Venable ◽

M. Calhoun ◽

L. Miloshevich ◽

...

Keyword(s):

Water Vapor ◽

Atmospheric Water Vapor ◽

Atmospheric Composition ◽

Lidar Data ◽

Atmospheric Effects ◽

Raman Lidar ◽

Atmospheric Water ◽

Atmospheric Variability ◽

Upper Troposphere ◽

Correction Technique

Abstract. The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE (Atmospheric Laboratory for Validation, Interagency Collaboration and Education) mobile laboratory in the MOHAVE-2009 campaign. In appendices we also report on the performance of the corrected Vaisala RS92 radiosonde measurements during the campaign, on a new radiosonde based calibration algorithm that reduces the influence of atmospheric variability on the derived calibration constant, and on other results of the ALVICE deployment. The MOHAVE-2009 campaign permitted the Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated, revealing that wet biases in upper tropospheric (UT) and lower stratospheric (LS) water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the bias. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Good agreement is found between corrected ALVICE lidar measurments and those of RS92, frost point hygrometer and total column water. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most robust. The correction shown here holds promise for permitting useful upper tropospheric water vapor profiles to be consistently measured by Raman lidar within NDACC (Network for the Detection of Atmospheric Composition Change) and elsewhere, despite the prevalence of instrumental and atmospheric effects that can contaminate the very low signal to noise measurements in the UT.

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A Satellite-Based Assessment of Upper-Tropospheric Water Vapor Measurements during AFWEX

Journal of Applied Meteorology and Climatology ◽

10.1175/2009jamc2250.1 ◽

2009 ◽

Vol 48 (11) ◽

pp. 2284-2294 ◽

Cited By ~ 5

Author(s):

Eui-Seok Chung ◽

Brian J. Soden

Keyword(s):

Water Vapor ◽

Radiative Transfer Model ◽

Transfer Model ◽

Raman Lidar ◽

Test Bed ◽

Upper Troposphere ◽

Brightness Temperatures ◽

Radiation Test ◽

Humidity Measurements ◽

Atmospheric Radiation Measurement

Abstract Consistency of upper-tropospheric water vapor measurements from a variety of state-of-the-art instruments was assessed using collocated Geostationary Operational Environmental Satellite-8 (GOES-8) 6.7-μm brightness temperatures as a common benchmark during the Atmospheric Radiation Measurement Program (ARM) First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE) Water Vapor Experiment (AFWEX). To avoid uncertainties associated with the inversion of satellite-measured radiances into water vapor quantity, profiles of temperature and humidity observed from in situ, ground-based, and airborne instruments are inserted into a radiative transfer model to simulate the brightness temperature that the GOES-8 would have observed under those conditions (i.e., profile-to-radiance approach). Comparisons showed that Vaisala RS80-H radiosondes and Meteolabor Snow White chilled-mirror dewpoint hygrometers are systemically drier in the upper troposphere by ∼30%–40% relative to the GOES-8 measured upper-tropospheric humidity (UTH). By contrast, two ground-based Raman lidars (Cloud and Radiation Test Bed Raman lidar and scanning Raman lidar) and one airborne differential absorption lidar agree to within 10% of the GOES-8 measured UTH. These results indicate that upper-tropospheric water vapor can be monitored by these lidars and well-calibrated, stable geostationary satellites with an uncertainty of less than 10%, and that correction procedures are required to rectify the inherent deficiencies of humidity measurements in the upper troposphere from these radiosondes.

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Effect of tropical cyclones on the Stratosphere-Troposphere Exchange observed using satellite observations over north Indian Ocean

10.5194/acp-2015-988 ◽

2016 ◽

Cited By ~ 3

Author(s):

M. Venkat Ratnam ◽

S. Ravindra Babu ◽

S. S. Das ◽

Ghouse Basha ◽

B. V. Krishnamurthy ◽

...

Keyword(s):

Water Vapor ◽

Indian Ocean ◽

Tropical Cyclones ◽

Lower Stratosphere ◽

North Indian Ocean ◽

Satellite Observations ◽

Upper Troposphere ◽

North West ◽

The North ◽

The Impact

Abstract. Tropical cyclones play an important role in modifying the tropopause structure and dynamics as well as stratosphere-troposphere exchange (STE) process in the Upper Troposphere and Lower Stratosphere (UTLS) region. In the present study, the impact of cyclones that occurred over the North Indian Ocean during 2007–2013 on the STE process is quantified using satellite observations. Tropopause characteristics during cyclones are obtained from the Global Positioning System (GPS) Radio Occultation (RO) measurements and ozone and water vapor concentrations in UTLS region are obtained from Aura-Microwave Limb Sounder (MLS) satellite observations. The effect of cyclones on the tropopause parameters is observed to be more prominent within 500 km from the centre of cyclone. In our earlier study we have observed decrease (increase) in the tropopause altitude (temperature) up to 0.6 km (3 K) and the convective outflow level increased up to 2 km. This change leads to a total increase in the tropical tropopause layer (TTL) thickness of 3 km within the 500 km from the centre of cyclone. Interestingly, an enhancement in the ozone mixing ratio in the upper troposphere is clearly noticed within 500 km from cyclone centre whereas the enhancement in the water vapor in the lower stratosphere is more significant on south-east side extending from 500–1000 km away from the cyclone centre. We estimated the cross-tropopause mass flux for different intensities of cyclones and found that the mean flux from stratosphere to troposphere for cyclonic stroms is 0.05 ± 0.29 × 10−3 kg m−2 and for very severe cyclonic stroms it is 0.5 ± 1.07 × 10−3 kg m−2. More downward flux is noticed in the north-west and south-west side of the cyclone centre. These results indicate that the cyclones have significant impact in effecting the tropopause structure, ozone and water vapour budget and consequentially the STE in the UTLS region.

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