scholarly journals Profiling water vapor mixing ratios in Finland by means of a Raman lidar, a satellite and a model

2017 ◽  
Vol 10 (11) ◽  
pp. 4303-4316 ◽  
Author(s):  
Maria Filioglou ◽  
Anna Nikandrova ◽  
Sami Niemelä ◽  
Holger Baars ◽  
Tero Mielonen ◽  
...  
Keyword(s):  
Water Vapor ◽  
Weather Prediction ◽  
Limited Area ◽  
Mixing Ratio ◽  
Atmospheric Conditions ◽  
Raman Lidar ◽  
Mixing Ratios ◽  
Seasonal Analysis ◽  
Relative Errors ◽  
Water Vapor Mixing Ratio

Abstract. We present tropospheric water vapor profiles measured with a Raman lidar during three field campaigns held in Finland. Co-located radio soundings are available throughout the period for the calibration of the lidar signals. We investigate the possibility of calibrating the lidar water vapor profiles in the absence of co-existing on-site soundings using water vapor profiles from the combined Advanced InfraRed Sounder (AIRS) and the Advanced Microwave Sounding Unit (AMSU) satellite product; the Aire Limitée Adaptation dynamique Développement INternational and High Resolution Limited Area Model (ALADIN/HIRLAM) numerical weather prediction (NWP) system, and the nearest radio sounding station located 100 km away from the lidar site (only for the permanent location of the lidar). The uncertainties of the calibration factor derived from the soundings, the satellite and the model data are  < 2.8, 7.4 and 3.9 %, respectively. We also include water vapor mixing ratio intercomparisons between the radio soundings and the various instruments/model for the period of the campaigns. A good agreement is observed for all comparisons with relative errors that do not exceed 50 % up to 8 km altitude in most cases. A 4-year seasonal analysis of vertical water vapor is also presented for the Kuopio site in Finland. During winter months, the air in Kuopio is dry (1.15±0.40 g kg−1); during summer it is wet (5.54±1.02 g kg−1); and at other times, the air is in an intermediate state. These are averaged values over the lowest 2 km in the atmosphere. Above that height a quick decrease in water vapor mixing ratios is observed, except during summer months where favorable atmospheric conditions enable higher mixing ratio values at higher altitudes. Lastly, the seasonal change in disagreement between the lidar and the model has been studied. The analysis showed that, on average, the model underestimates water vapor mixing ratios at high altitudes during spring and summer.

scholarly journals Profiling water vapor mixing ratios in Finland by means of a Raman lidar, a satellite and a model

2017 ◽  
Author(s):  
Maria Filioglou ◽  
Anna Nikandrova ◽  
Sami Niemelä ◽  
Holger Baars ◽  
Tero Mielonen ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Resolution ◽  
Weather Prediction ◽  
Microwave Radiometer ◽  
Limited Area ◽  
Raman Lidar ◽  
Model Data ◽  
Mixing Ratios ◽  
Field Campaigns ◽  
Satellite Product

Abstract. We present tropospheric water vapor profiles measured with a Raman lidar during three field campaigns held in Finland. Co-located radio soundings are available throughout the period for the calibration of the lidar signals. We investigate the possibility of calibrating the lidar water vapor profiles in the absence of co-existing on site soundings using water vapor profiles from the combined Advanced Infrared Sounder (AIRS) and the Advanced Microwave Radiometer (AMSU) satellite product; the Aire Limitee Adaptation dynamique Development International and High Resolution Limited Area Model (ALADIN HIRLAM) numerical weather prediction (NWP) system, and the nearest radio sounding station located 100 km away from the lidar site (only for the permanent location of the lidar). The uncertainties of the calibration factor derived from the soundings, the satellite and the model data are

scholarly journals Temperature profiling of the atmospheric boundary layer with rotational Raman lidar during the HD(CP)<sup>2</sup> Observational Prototype Experiment

2015 ◽  
Vol 15 (5) ◽  
pp. 2867-2881 ◽  
Author(s):  
E. Hammann ◽  
A. Behrendt ◽  
F. Le Mounier ◽  
V. Wulfmeyer
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Temperature Gradient ◽  
Atmospheric Boundary Layer ◽  
Average Power ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Backscatter Signal ◽  
Low Background ◽  
Water Vapor Mixing Ratio

Abstract. The temperature measurements of the rotational Raman lidar of the University of Hohenheim (UHOH RRL) during the High Definition of Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observation Prototype Experiment (HOPE) in April and May 2013 are discussed. The lidar consists of a frequency-tripled Nd:YAG laser at 355 nm with 10 W average power at 50 Hz, a two-mirror scanner, a 40 cm receiving telescope, and a highly efficient polychromator with cascading interference filters for separating four signals: the elastic backscatter signal, two rotational Raman signals with different temperature dependence, and the vibrational Raman signal of water vapor. The main measurement variable of the UHOH RRL is temperature. For the HOPE campaign, the lidar receiver was optimized for high and low background levels, with a novel switch for the passband of the second rotational Raman channel. The instrument delivers atmospheric profiles of water vapor mixing ratio as well as particle backscatter coefficient and particle extinction coefficient as further products. As examples for the measurement performance, measurements of the temperature gradient and water vapor mixing ratio revealing the development of the atmospheric boundary layer within 25 h are presented. As expected from simulations, a reduction of the measurement uncertainty of 70% during nighttime was achieved with the new low-background setting. A two-mirror scanner allows for measurements in different directions. When pointing the scanner to low elevation, measurements close to the ground become possible which are otherwise impossible due to the non-total overlap of laser beam and receiving telescope field of view in the near range. An example of a low-level temperature measurement is presented which resolves the temperature gradient at the top of the stable nighttime boundary layer 100 m above the ground.

scholarly journals Water Vapor Calibration: Using a Raman Lidar and Radiosoundings to Obtain Highly Resolved Water Vapor Profiles

2019 ◽  
Vol 11 (6) ◽  
pp. 616 ◽  
Author(s):  
Birte Kulla ◽  
Christoph Ritter
Keyword(s):  
Water Vapor ◽  
Correlation Coefficients ◽  
Small Scale ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Independent Information ◽  
European Arctic ◽  
Water Vapor Mixing Ratio ◽  
A Site ◽  
Individual Profiles

We revised the calibration of a water vapor Raman lidar by co-located radiosoundings for a site in the high European Arctic. For this purpose, we defined robust criteria for a valid calibration. One of these criteria is the logarithm of the water vapor mixing ratio between the sonde and the lidar. With an error analysis, we showed that for our site correlations smaller than 0.95 could be explained neither by noise in the lidar nor by wrong assumptions concerning the aerosol or Rayleigh extinction. However, highly variable correlation coefficients between sonde and consecutive lidar profiles were found, suggesting that small scale variability of the humidity was our largest source of error. Therefore, not all co-located radiosoundings are useful for lidar calibration. As we assumed these changes to be non-systematic, averaging over several independent measurements increased the calibration’s quality. The calibration of the water vapor measurements from the lidar for individual profiles varied by less than ±5%. The seasonal median, used for calibration in this study, was stable and reliable (confidence ±1% for the season with most calibration profiles). Thus, the water vapor mixing ratio profiles from the Koldewey Aerosol Raman Lidar (KARL) are very accurate. They show high temporal variability up to 4 km altitude and, therefore, provide additional, independent information to the radiosonde.

scholarly journals Water Vapor Mixing Ratio Distribution Inversion by Raman Lidar in Beijing

2020 ◽  
Vol 237 ◽  
pp. 06020
Author(s):  
SiQi Yu ◽  
Dong Liu ◽  
JiWei Xu ◽  
ZhenZhu Wang ◽  
DeCheng Wu ◽  
...  
Keyword(s):  
Water Vapor ◽  
Radiosonde Data ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Ratio Distribution ◽  
Water Vapor Mixing Ratio ◽  
Detection Instrument ◽  
Active Detection ◽  
The Vertical Distribution ◽  
Good Agreement

Water Aerosol Raman Lidar-II is an active detection instrument with high temporal and spatial resolution at Nanjiao observation station, and that could continuous water vapor mixing ratio (WVMR) measurements. WVMR profiles inversion from lidar data and water ratio retrieved from radiosonde data are in good agreement. The statistical results of the vertical distribution of WVMR indicate that WVMR seasonal mean distribution is consistent with precipitation. In addition, WVMR in Nanjiao station is related to total cloud cover.

scholarly journals A Remotely Operated Lidar for Aerosol, Temperature, and Water Vapor Profiling in the High Arctic

2012 ◽  
Vol 29 (2) ◽  
pp. 221-234 ◽  
Author(s):  
G. J. Nott ◽  
T. J. Duck ◽  
J. G. Doyle ◽  
M. E. W. Coffin ◽  
C. Perro ◽  
...  
Keyword(s):  
Water Vapor ◽  
Measurement Techniques ◽  
High Arctic ◽  
Interference Filter ◽  
Fine Tuning ◽  
The Arctic ◽  
Tropospheric Temperature ◽  
Mixing Ratio ◽  
Atmospheric Conditions ◽  
Water Vapor Mixing Ratio

Abstract A Rayleigh–Mie–Raman lidar has been installed and is operating in the Polar Environment Atmospheric Research Laboratory at Eureka in the High Arctic (79°59′N, 85°56′W) as part of the Canadian Network for the Detection of Atmospheric Change. The lidar operates in both the visible and ultraviolet and measures aerosol backscatter and extinction coefficients, depolarization ratio, tropospheric temperature, and water vapor mixing ratio. Variable field of view, aperture, and filtering allow fine-tuning of the instrument for different atmospheric conditions. Because of the remote location, operations are carried out via a satellite link. The instrument is introduced along with the measurement techniques utilized and interference filter specifications. The temperature dependence of the water vapor signal depends on the filter specifications, and this is discussed in terms of minimizing the uncertainty of the water vapor mixing ratio product. Finally, an example measurement is presented to illustrate the potential of this instrument for studying the Arctic atmosphere.

scholarly journals Comparison of IASI water vapor retrieval with H<sub>2</sub>O-Raman lidar in the framework of the Mediterranean HyMeX and ChArMEx programs

2014 ◽  
Vol 14 (18) ◽  
pp. 9583-9596 ◽  
Author(s):  
P. Chazette ◽  
F. Marnas ◽  
J. Totems ◽  
X. Shang
Keyword(s):  
Water Vapor ◽  
Root Mean Square ◽  
Vertical Profiles ◽  
Mean Square ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Operational Level ◽  
The Mediterranean ◽  
Water Vapor Mixing Ratio ◽  
Level 2

Abstract. The Infrared Atmospheric Sounding Interferometer (IASI) is a new generation spaceborne passive sensor mainly dedicated to meteorological applications. Operational Level-2 products have been available via the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) for several years. In particular, vertical profiles of water vapor measurements are retrieved from infrared radiances at the global scale. Nevertheless, the robustness of such products has to be checked because only a few validations have been reported. For this purpose, the field experiments that were held during the HyMeX and ChArMEx international programs are a very good opportunity. A H2O-Raman lidar was deployed on the Balearic island of Menorca and operated continuously for ~ 6 and ~ 3 weeks during fall 2012 (Hydrological cycle in the Mediterranean eXperiment – HyMeX) and summer 2013 (Chemistry–Aerosol Mediterranean Experiment – ChArMEx), respectively. It measured simultaneously the water vapor mixing ratio and aerosol optical properties. This article does not aim to describe the IASI operational H2O inversion algorithm, but to compare the vertical profiles derived from IASI onboard (meteorological operational) MetOp-A and the ground-based lidar measurements to assess the reliability of the IASI operational product for the water vapor retrieval in both the lower and middle troposphere. The links between water vapor contents and both the aerosol vertical profiles and the air mass origins are also studied. About 30 simultaneous observations, performed during nighttime in cloud free conditions, have been considered. For altitudes ranging from 2 to 7 km, root mean square errors (correlation) of ~ 0.5 g kg−1 (~ 0.77) and ~ 1.1 g kg−1 (~ 0.72) are derived between the operational IASI product and the available lidar profiles during HyMeX and ChArMEx, respectively. The values of both root mean square error and correlation are meaningful and show that the operational Level-2 product of the IASI-derived vertical water vapor mixing ratio can be considered for meteorological and climatic applications, at least in the framework of field campaigns.

Demonstration Measurements of Water Vapor, Cirrus Clouds, and Carbon Dioxide Using a High-Performance Raman Lidar

2007 ◽  
Vol 24 (8) ◽  
pp. 1377-1388 ◽  
Author(s):  
David N. Whiteman ◽  
Kurt Rush ◽  
Igor Veselovskii ◽  
Martin Cadirola ◽  
Joseph Comer ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Boundary Layer ◽  
Water Vapor ◽  
High Performance ◽  
Cirrus Clouds ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Cloud Optical Depth ◽  
Temporal And Spatial ◽  
Water Vapor Mixing Ratio

Abstract Profile measurements of atmospheric water vapor, cirrus clouds, and carbon dioxide using the Raman Airborne Spectroscopic lidar (RASL) during ground-based, upward-looking tests are presented here. These measurements improve upon any previously demonstrated using Raman lidar. Daytime boundary layer profiling of water vapor mixing ratio up to an altitude of approximately 4 km under moist, midsummer conditions is performed with less than 5% random error using temporal and spatial resolution of 2 min and 60–210 m, respectively. Daytime cirrus cloud optical depth and extinction-to-backscatter ratio measurements are made using a 1-min average. The potential to simultaneously profile carbon dioxide and water vapor mixing ratio through the boundary layer and extending into the free troposphere during the nighttime is also demonstrated.

Direct injection of water vapor into the lower stratosphere through extreme convection: A case study for the summer 2019 in the mid latitudes

2020 ◽  
Author(s):  
Dina Khordakova ◽  
Christian Rolf ◽  
Martina Krämer ◽  
Martin Riese
Keyword(s):  
Water Vapor ◽  
Satellite Images ◽  
Lower Stratosphere ◽  
Global Climate ◽  
Direct Injection ◽  
Reanalysis Data ◽  
Radiation Budget ◽  
Mixing Ratio ◽  
Mixing Ratios ◽  
Water Vapor Mixing Ratio

&lt;p&gt;Water vapor is one of the strongest greenhouse gases of the atmosphere. Its driving role in the upper troposphere / lower stratosphere region (UTLS) for the radiation budget was shown by e.g. Riese et al., (2012). Despite its low abundance of 4 - 6 ppmv in the stratosphere, even small changes in its mixing ratio can leed to a positive feedback to global warming. To better understand changes and variability of water vapor in the lower stratosphere, we focus here on exchange processes from the moist troposphere to the dry stratosphere in the mid latitudes. These processes are caused by extreme vertical convection, which is expected to increase in intensity and frequency with progressive global climate change.&lt;/p&gt;&lt;p&gt;Within the MOSES (Modular Observation Solutions for Earth Systems) campaign in the summer of 2019, two extreme vertical convection events could be captured with balloon borne humidity sensors over the eastern part of Germany. The comparison of measurements before and after both events reveal distinct water vapor enhancements in the lower stratosphere and show that even in mid-latitudes over shooting convection can impact the water vapor mixing ratio in the UTLS. The measurements are compared with the Microwave Limb Sounder (MLS) data as well as ECMWF reanalysis data.&lt;/p&gt;&lt;p&gt;&lt;span&gt;We will show a deeper analysis of both events by using visible and infrared weather satellite images in combination with meteorological fields of ECMWF. &lt;/span&gt;&lt;span&gt;B&lt;/span&gt;&lt;span&gt;ackward trajectories of the air masses &lt;/span&gt;&lt;span&gt;with the enriched water vapor mixing ratios &lt;/span&gt;&lt;span&gt;calculated with&lt;/span&gt;&lt;span&gt; the CLAMS model &lt;/span&gt;&lt;span&gt;and&lt;/span&gt; &lt;span&gt;combined&lt;/span&gt;&lt;span&gt; with the satellite images can &lt;/span&gt;&lt;span&gt;confirm the convective origin. &lt;/span&gt;&lt;span&gt;Additionally,&lt;/span&gt;&lt;span&gt; we show the &lt;/span&gt;&lt;span&gt;further &lt;/span&gt;&lt;span&gt;development of this distinct water vapor filaments within the lower stratosphere &lt;/span&gt;&lt;span&gt;in order to&lt;/span&gt;&lt;span&gt; trace the transport and mixing process, &lt;/span&gt;&lt;span&gt;based on an&lt;/span&gt; &lt;span&gt;analysis of forward trajectories.&lt;/span&gt;&lt;/p&gt;

scholarly journals Water Vapor Measurements by Howard University Raman Lidar during the WAVES 2006 Campaign

2010 ◽  
Vol 27 (1) ◽  
pp. 42-60 ◽  
Author(s):  
M. Adam ◽  
B. B. Demoz ◽  
D. D. Venable ◽  
E. Joseph ◽  
R. Connell ◽  
...  
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Relative Difference ◽  
Mixing Ratio ◽  
State Variables ◽  
Raman Lidar ◽  
Ensemble Averaging ◽  
Howard University ◽  
Validation Experiment ◽  
Water Vapor Mixing Ratio

Abstract Water vapor mixing ratio retrieval using the Howard University Raman lidar is presented with emphasis on three aspects: (i) comparison of the lidar with collocated radiosondes and Raman lidar, (ii) investigation of the relationship between atmospheric state variables and the relative performance of the lidar and sonde (in particular, their poor agreement), and (iii) comparison with satellite-based measurements. The measurements were acquired during the Water Vapor Validation Experiment Sondes/Satellites 2006 campaign. Ensemble averaging of water vapor mixing ratio data from 10 nighttime comparisons with Vaisala RS92 radiosondes shows, on average, an agreement within ±10%, up to ∼8 km. A similar analysis of lidar-to-lidar data of over 700 profiles revealed an agreement to within 20% over the first 7 km (10% below 4 km). A grid analysis, defined in the temperature–relative humidity space, was developed to characterize the lidar–radiosonde agreement and quantitatively localizes regions of strong and weak correlations as a function of altitude, temperature, or relative humidity. Three main regions of weak correlation emerge: (i) regions of low relative humidity and low temperature, (ii) regions of moderate relative humidity at low temperatures, and (iii) regions of low relative humidity at moderate temperatures. Comparison of Atmospheric Infrared Sounder and Tropospheric Emission Sounder satellite retrievals of moisture with those of Howard University Raman lidar showed a general agreement in the trend, but the satellites miss details in atmospheric structure because of their low resolution. A relative difference of about ±20% is usually found between lidar and satellite measurements for the coincidences available.

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