A new lidar design for operational atmospheric wind and cloud/aerosol survey from space

Abstract. Global wind profile measurement has, for a long time, been a first priority for numerical weather prediction. The demonstration, from ground-based observations, that a double-edge Fabry–Pérot interferometer could be efficiently used for deriving wind profiles from the molecular scattered signal in a very large atmospheric vertical domain has led to the choice of the direct detection technique in space and the selection of the Atmospheric Dynamics Mission (ADM)-Aeolus by the European Space Agency (ESA) in 1999. ADM-Aeolus was successfully launched in 2018, after the technical issues raised by the lidar development had been solved, providing the first global wind profiles from space in the whole troposphere. Simulated and real-time assimilation of the projected horizontal wind information was able to confirm the expected improvements in the forecast score, validating the concept of a wind profiler using a single line-of-sight lidar from space. The question is raised here about consolidating the results gained from ADM-Aeolus mission with a potential operational follow-on instrument. Maintaining the configuration of the instrument as close as possible to the one achieved (UV emission lidar with a single line of sight), we revisit the concept of the receiver by replacing the arrangement of the Fizeau and Fabry–Pérot interferometers with a unique quadri-channel Mach–Zehnder (QMZ) interferometer, which relaxes the system's operational constraints and extends the observation capabilities to recover the radiative properties of clouds. This ability to profile wind and cloud/aerosol radiative properties enables the meeting of the two highest priorities of the meteorological forecasting community regarding atmospheric dynamics and radiation. We discuss the optimization of the key parameters necessary in the selection of a high-performance system, as based on previous work and development of our airborne QMZ lidar. The selected optical path difference (3.2 cm) of the QMZ leads to a very compact design, allowing the realization of a high-quality interferometer and offering a large field angle acceptance. Performance simulation of horizontal wind speed measurements with different backscatter profiles shows results in agreement with the targeted ADM-Aeolus random errors, using an optimal 45∘ line-of-sight angle. The Doppler measurement is, in principle, unbiased by the atmospheric conditions (temperature, pressure, and particle scattering) and only weakly affected by the instrument calibration errors. The study of the errors arising from the uncertainties in the instrumental calibration and in the modeled atmospheric parameters used for the backscattered signal analysis shows a limited impact under realistic conditions. The particle backscatter coefficients can be retrieved with uncertainties better than a few percent when the scattering ratio exceeds 2, such as in the boundary layer and in semi-transparent clouds. Extinction coefficients can be derived accordingly. The chosen design further allows the addition of a dedicated channel for aerosol and cloud polarization analysis.

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A new lidar design for operational atmospheric wind and cloud/aerosol survey from space

10.5194/amt-2020-487 ◽

2020 ◽

Author(s):

Didier Bruneau ◽

Jacques Pelon

Keyword(s):

Weather Prediction ◽

Radiative Properties ◽

Large Field ◽

Horizontal Wind ◽

Line Of Sight ◽

Profile Measurement ◽

Random Errors ◽

Fabry Perot ◽

Wind Profiles ◽

Selection Of

Abstract. Global wind profile measurement has for long been a first priority for numerical weather prediction. The demonstration from ground-based observations that a double-edge Fabry-Perot interferometer could be efficiently used for deriving wind profiles from the molecular scattered signal in a very large atmospheric vertical domain has led to the choice of the direct detection technique in space and the selection of the Atmospheric Dynamic Mission (ADM) Aeolus by ESA in 1999. ADM-Aeolus was successfully launched in 2018, after the technical issues raised for the lidar development have been solved, providing first global wind profiles from space in the whole troposphere. Simulated and real time assimilation of the projected horizontal wind information were able to confirm the expected improvements in forecast score, validating the concept of a wind profiler using a fixed line-of-sight lidar from space. The question is raised here about consolidating results gained from ADM-Aeolus mission with a potential operational follow-on instrument. Maintaining the configuration of the instrument as close as possible to the one achieved (UV emission lidar with a single slanted line-of-sight) we revisit the concept of the receiver by replacing the arrangement of the Fizeau and Fabry-Perot interferometers with a unique Quadri-channel Mach-Zehnder (QMZ) interferometer which relaxes the system operational constraints and extends the observation capabilities to recover the radiative properties of clouds. This ability is meeting first and second profiling priorities of the meteorological forecasting community on atmospheric dynamics and radiation. We discuss the optimization of the key parameters that may preside to the selection of a high performance system. The selected optical path difference (3.2 cm) of the QMZ leads to a very compact design allowing the realization of a high quality interferometer and offering a large field-angle acceptance. Performance simulation of horizontal wind speed measurements with different backscatter profiles shows results in agreement with the targeted ADM-Aeolus random errors, using an optimal 45° line-of-sight angle. The Doppler measurement is, from principle, unbiased by the atmospheric conditions (temperature, pressure, particle scattering) and only weakly affected by the instrument calibration errors. The study of the random systematic errors arising from the uncertainties in the instrumental calibration and in the modelled atmospheric parameters used for the backscatter analysis shows a limited impact under realistic conditions. The particle backscatter coefficients can be retrieved with uncertainties better than a few percent in the boundary layer and in semi-transparent clouds. Extinction coefficients and depolarization ratio can be derived accordingly.

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On the derivation of zonal and meridional wind components from Aeolus horizontal line-of-sight wind

10.5194/amt-2021-381 ◽

2021 ◽

Author(s):

Isabell Krisch ◽

Neil P. Hindley ◽

Oliver Reitebuch ◽

Corwin J. Wright

Keyword(s):

Lower Stratosphere ◽

Weather Prediction ◽

Meridional Wind ◽

Atmospheric Dynamics ◽

Horizontal Wind ◽

Line Of Sight ◽

Wind Component ◽

Horizontal Line ◽

Sigma Level ◽

Wind Measurements

Abstract. Since its launch in 2018, the European Space Agency’s Earth Explorer satellite Aeolus has provided global height resolved measurements of horizontal wind in the troposphere and lower stratosphere for the first time. Novel datasets such as these provide an unprecedented opportunity for the research of atmospheric dynamics and provide new insights into the dynamics of the upper troposphere and lower stratosphere (UTLS) region. Aeolus measures the wind component along its horizontal line-of-sight, but for the analysis and interpretation of atmospheric dynamics, zonal and/or meridional wind components are most useful. In this paper, we introduce and compare three different methods to derive zonal and meridional wind components from the Aeolus wind measurements. We find that the most promising method involves combining Aeolus measurements during ascending and descending orbits. Using this method, we derive global estimates of the zonal wind in the latitude range 79.7° S to 84.5° N with errors of less than 5 ms−1 (at the 2-sigma level). Due to the orbit geometry of Aeolus, the estimation of meridional wind in the tropics and at midlatitudes is more challenging and the quality is less reliable. However, we find that it is possible to derive meridional winds poleward of 70° latitude with absolute errors typically below ±5 ms−1 (at the 2-sigma level). This further demonstrate the value of Aeolus wind measurements for applications in weather and climate research, in addition to their important role in numerical weather prediction.

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Line-of-Sight Winds and Doppler Effect Smearing in ACE-FTS Solar Occultation Measurements

Atmosphere ◽

10.3390/atmos12060680 ◽

2021 ◽

Vol 12 (6) ◽

pp. 680

Author(s):

Chris D. Boone ◽

Johnathan Steffen ◽

Jeff Crouse ◽

Peter F. Bernath

Keyword(s):

Atmospheric Chemistry ◽

Doppler Effect ◽

Line Of Sight ◽

Measured Signal ◽

Mixing Ratio ◽

Model Calculations ◽

Doppler Shifts ◽

Solar Occultation ◽

Wide Range ◽

Wind Profiles

Line-of-sight wind profiles are derived from Doppler shifts in infrared solar occultation measurements from the Atmospheric Chemistry Experiment Fourier transform spectrometers (ACE-FTS), the primary instrument on SCISAT, a satellite-based mission for monitoring the Earth’s atmosphere. Comparisons suggest a possible eastward bias from 20 m/s to 30 m/s in ACE-FTS results above 80 km relative to some datasets but no persistent bias relative to other datasets. For instruments operating in a limb geometry, looking through a wide range of altitudes, smearing of the Doppler effect along the line of sight can impact the measured signal, particularly for saturated absorption lines. Implications of Doppler effect smearing are investigated for forward model calculations and volume mixing ratio retrievals. Effects are generally small enough to be safely ignored, except for molecules having a large overhang in their volume mixing ratio profile, such as carbon monoxide.

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Effects of atmospheric dynamics and aerosols on the fraction of supercooled water clouds

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-1847-2017 ◽

2017 ◽

Vol 17 (3) ◽

pp. 1847-1863 ◽

Cited By ~ 30

Author(s):

Jiming Li ◽

Qiaoyi Lv ◽

Min Zhang ◽

Tianhe Wang ◽

Kazuaki Kawamoto ◽

...

Keyword(s):

Relative Humidity ◽

Vertical Velocity ◽

Meteorological Parameters ◽

Temporal Correlation ◽

Supercooled Liquid ◽

Satellite Observation ◽

Static Stability ◽

Global Scale ◽

Atmospheric Dynamics ◽

Horizontal Wind

Abstract. Based on 8 years of (January 2008–December 2015) cloud phase information from the GCM-Oriented Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Cloud Product (GOCCP), aerosol products from CALIPSO and meteorological parameters from the ERA-Interim products, the present study investigates the effects of atmospheric dynamics on the supercooled liquid cloud fraction (SCF) during nighttime under different aerosol loadings at global scale to better understand the conditions of supercooled liquid water gradually transforming to ice phase. Statistical results indicate that aerosols' effect on nucleation cannot fully explain all SCF changes, especially in those regions where aerosols' effect on nucleation is not a first-order influence (e.g., due to low ice nuclei aerosol frequency). By performing the temporal and spatial correlations between SCFs and different meteorological factors, this study presents specifically the relationship between SCF and different meteorological parameters under different aerosol loadings on a global scale. We find that the SCFs almost decrease with increasing of aerosol loading, and the SCF variation is closely related to the meteorological parameters but their temporal relationship is not stable and varies with the different regions, seasons and isotherm levels. Obviously negative temporal correlations between SCFs versus vertical velocity and relative humidity indicate that the higher vertical velocity and relative humidity the smaller SCFs. However, the patterns of temporal correlation for lower-tropospheric static stability, skin temperature and horizontal wind are relatively more complex than those of vertical velocity and humidity. For example, their close correlations are predominantly located in middle and high latitudes and vary with latitude or surface type. Although these statistical correlations have not been used to establish a certain causal relationship, our results may provide a unique point of view on the phase change of mixed-phase cloud and have potential implications for further improving the parameterization of the cloud phase and determining the climate feedbacks.

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Effect Analysis of Polarization Aberration in the Non-Line-of-Sight Azimuth Transmission

10.21203/rs.3.rs-152914/v1 ◽

2021 ◽

Author(s):

Zhiyong Yang ◽

Junchen Song ◽

Wei Cai ◽

Danqiu Qiao ◽

Gaoxiang Lu

Keyword(s):

Normal Incidence ◽

Transmission Error ◽

Transmission System ◽

Line Of Sight ◽

Polarization Angle ◽

Effect Analysis ◽

Polarized Beam ◽

Polarization Maintaining ◽

Selection Of ◽

Non Line Of Sight

Abstract Focusing on the problem that the polarization aberration caused by the non-normal incidence of the polarized beam affects the accuracy of the azimuth transmission during the fiber coupling process of the non-line-of-sight azimuth transmission system, this paper starts from the principle of non-line-of-sightazimuth transmission. The polarization aberration relation of the lens-fiber combined interface is established based on the Fresnel formulafor the attenuation difference between the horizontal and vertical electric vectors. Further, the azimuth solution model affected by polarization aberration is established. Numerical simulation results show that in non-normal incidence, no polarization aberration will occur when the polarization angle between the incident ray and incident surface is 0° or 90°. Otherwise, the polarization aberration changes toward the incident surface, and the azimuth transmission error will increase with the increase of the polarization aberration. Last, the optimization measures are proposed. This is of great significancefor further improvement of the azimuth transmission system based on polarization-maintaining fibers, the selection of the instrument,and the improvement of the system measurement accuracy.

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Selection of the Separation of the Plates of the Fabry-Perot Interferometer

Journal of the Optical Society of America ◽

10.1364/josa.44.0253_1 ◽

1954 ◽

Vol 44 (3) ◽

pp. 253_1 ◽

Cited By ~ 1

Author(s):

J. Blaise ◽

H. Chantrel ◽

P. Giacomo ◽

D. A. Jackson

Keyword(s):

Fabry Perot ◽

Selection Of

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First Demonstration of an Acousto-Optically Modulated Quantum Cascade Laser As a Broadband, Time-Resolved Combustion Diagnostic

Volume 4A: Combustion, Fuels, and Emissions ◽

10.1115/gt2018-75424 ◽

2018 ◽

Author(s):

Zachary E. Loparo ◽

Kareem Ahmed ◽

Subith S. Vasu ◽

Andrey V. Muraviev ◽

Pedro Figueiredo ◽

...

Keyword(s):

Quantum Cascade Laser ◽

Gas Turbines ◽

Chemical Kinetic ◽

Single Line ◽

Line Of Sight ◽

Spectral Measurements ◽

Time Resolved ◽

Quantum Cascade ◽

No Formation ◽

Multiple Species

We provide the first demonstration of an acousto-optically modulated quantum cascade laser (AOM QCL) system as a diagnostic for combustion by measuring nitric oxide (NO), a highly-regulated emission produced in gas turbines. The system provides time-resolved broadband spectral measurements of the present gas species via a single line of sight measurement, offering advantages over widely used narrowband absorption spectroscopy (e.g., the potential for simultaneous multi-species measurements using a single laser) and considerably faster (> 15kHz rates and potentially up to MHz) than sampling techniques which employ FTIR or GC/MS. The developed AOM QCL system yields fast tunable output covering a spectral range of 1725–1930 cm−1 with a linewidth of 10–15 cm−1. For the demonstration experiment, the AOM QCL system has been used to obtain time-resolved spectral measurements of NO formation during the shock heating of mixture of a 10% nitrous oxide (N2O) in a balance of argon over a temperature range of 1245–2517 K and a pressure range of 3.6–5.8 atm. Results were in good agreement with chemical kinetic simulations. The system shows revolutionary promise for making simultaneous time-resolved measurements of multiple species concentrations and temperature with a single line of sight measurement.

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Wind profile correction algorithm based on Atmospheric Boundary Layer stability profile

10.5194/ems2021-341 ◽

2021 ◽

Author(s):

Francisco Albuquerque Neto ◽

Vinicius Almeida ◽

Julia Carelli

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Wind Profile ◽

Horizontal Wind ◽

Boundary Layer Stability ◽

Correction Algorithm ◽

Horizontal Wind Speed ◽

Study Region ◽

Profile Correction ◽

Wind Profiles

In recent years, the use of radar wind profilers (RWP) at airports has grown significantly with the aim of supporting decision makers to maintain the safety of aircraft landings and takeoffs.The RWP provide vertical profiles of averaged horizontal wind speed and direction and vertical wind velocity for the entire Atmospheric Boundary Layer (ABL) and beyond. In addition, RWP with Radio-Acoustic Sounding System (RASS) are able to retrieve virtual temperature profiles in the ABL.RWP data evaluation is usually based on the so-called Doppler Beam Swinging method (DBS) which assumes homogeneity and stationarity of the wind field. Often, transient eddies violate this homogeneity and stationarity requirement. Hence, incorrect wind profiles can relate to transient eddies and present a problem for the forecast of high-impact weather phenomena in airports. This work intends to provide a method for removing outliers in such profiles based on historical data and other variables related to the Atmospheric Boundary Layer stability profile in the study region.For this study, a dataset of almost one year retrieved from a RWP LAP3000 with RASS Extension is used for a wind profile correction algorithm development.The algorithm consists of the detection of outliers in the wind profiles based on the thermodynamic structure of the ABL and the generation of the corrected profiles.Results show that the algorithm is capable of identifying and correcting unrealistic variations in speed caused by transient eddies. The method can be applied as a complement to the RWP data processing for better data reliability.&#160;Keywords: atmospheric boundary layer; stability profile; wind profile

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Simulation study for the Stratospheric Inferred Winds (SIW) sub-millimeter limb sounder

10.5194/amt-2018-76 ◽

2018 ◽

Author(s):

Philippe Baron ◽

Donal Murtagh ◽

Patrick Eriksson ◽

Jana Mendrok ◽

Satoshi Ochiai ◽

...

Keyword(s):

Simulation Study ◽

Spectral Band ◽

Chemical Species ◽

Field Of View ◽

Emission Lines ◽

Horizontal Wind ◽

Line Of Sight ◽

Heterodyne Receiver ◽

Vertical Field ◽

Wind Measurements

Abstract. Stratospheric Inferred Winds (SIW) is a Swedish mini sub-millimeter limb sounder selected for the 2nd InnoSat platform launch planned near 2022. It is intended to fill the altitude gap between 30–70 km in atmospheric wind measurements and also aims at pursuing the limb observations of temperature and key atmospheric constituents between 10–90 km when current satellite missions are probably stopped. Line-of-sight winds are retrieved from the Doppler shift of the emission lines introduced by 5 the wind field. Observations will be performed with two antennas pointing toward the limb with perpendicular directions to reconstruct the 2-D horizontal wind vector. Each antenna has a vertical field of view of 5 km. The chosen spectral band near 655 GHz contains a dense group of strong O3 lines suitable for exploiting the small wind information in stratospheric spectra. Using both sidebands of the heterodyne receiver, a large number of chemical species will be measured including O3-isopotologues, H2O, HDO, HCl, ClO, N2O, HNO3, NO, NO2, HCN, CH3CN and HO2. This paper presents the simulation study for assessing the measurement performances. The line-of-sight winds are retrieved between 30–90 km with the best sensitivity between 35–70 km where the precision (1-sigma) is 5–10 m s−1 for a single scan. Similar performances can be obtained during day and night conditions except in the lower mesosphere where the photo-dissociation of O3 in day-time reduces the sensitivity by 50 % near 70 km. Profiles of O3, H2O and temperature are retrieved with a high precision up to 50 km (

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Direct radiative effect of the Russian wildfires and its impact on air temperature and atmospheric dynamics during August 2010

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-1999-2014 ◽

2014 ◽

Vol 14 (4) ◽

pp. 1999-2013 ◽

Cited By ~ 34

Author(s):

J. C. Péré ◽

B. Bessagnet ◽

M. Mallet ◽

F. Waquet ◽

I. Chiapello ◽

...

Keyword(s):

Optical Properties ◽

Wind Speed ◽

Eastern Europe ◽

Air Temperature ◽

Air Entrainment ◽

Atmospheric Dynamics ◽

Horizontal Wind ◽

Satellite Measurements ◽

Near Surface ◽

Aerosol Plume

Abstract. In this study, we investigate the shortwave aerosol direct radiative forcing (ADRF) and its feedback on air temperature and atmospheric dynamics during a major fire event that occurred in Russia during August 2010. The methodology is based on an offline coupling between the CHIMERE chemistry-transport and the Weather Research and Forecasting (WRF) models. First, simulations for the period 5–12 August 2010 have been evaluated by using AERONET (AErosol RObotic NETwork) and satellite measurements of the POLarization and Directionality of the Earth's Reflectance (POLDER) and the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) sensors. During this period, elevated POLDER aerosol optical thickness (AOT) is found over a large part of eastern Europe, with values above 2 (at 550 nm) in the aerosol plume. According to CALIOP observations, particles remain confined to the first five kilometres of the atmospheric layer. Comparisons with satellite measurements show the ability of CHIMERE to reproduce the regional and vertical distribution of aerosols during their transport from the source region. Over Moscow, AERONET measurements indicate an important increase of AOT (340 nm) from 0.7 on 5 August to 2–4 between 6 and 10 August when the aerosol plume was advected over the city. Particles are mainly observed in the fine size mode (radius in the range 0.2–0.4 μm) and are characterized by elevated single-scattering albedo (SSA) (0.95–0.96 between 440 and 1020 nm). Comparisons of simulations with AERONET measurements show that aerosol physical–optical properties (size distribution, AOT, SSA) have been well simulated over Moscow in terms of intensity and/or spectral dependence. Secondly, modelled aerosol optical properties have been used as input in the radiative transfer code of WRF to evaluate their direct radiative impact. Simulations indicate a significant reduction of solar radiation at the ground (up to 80–150 W m−2 in diurnal averages over a large part of eastern Europe due to the presence of the aerosol plume. This ADRF causes an important reduction of the near-surface air temperature between 0.2 and 2.6° on a regional scale. Moscow has been affected by the aerosol plume, especially between 6 and 10 August. During this period, aerosol causes a significant reduction of surface shortwave radiation (up to 70–84 W m−2 in diurnal averages) with a moderate part (20–30%) due to solar absorption within the aerosol layer. The resulting feedbacks lead to a cooling of the air up to 1.6° at the surface and 0.1° at an altitude of 1500–2000 m (in diurnal averages), that contribute to stabilize the atmospheric boundary layer (ABL). Indeed, a reduction of the ABL height of 13 to 65% has been simulated during daytime in presence of aerosols. This decrease is the result of a lower air entrainment as the vertical wind speed in the ABL is shown to be reduced by 5 to 80% (at midday) when the feedback of the ADRF is taken into account. However, the ADRF is shown to have a lower impact on the horizontal wind speed, suggesting that the dilution of particles would be mainly affected by the weakening of the ABL development and associated vertical entrainment. Indeed, CHIMERE simulations driven by the WRF meteorological fields including this ADRF feedback result in a large increase in the modelled near-surface PM10 concentrations (up to 99%). This is due to their lower vertical dilution in the ABL, which tend to reduce model biases with the ground PM10 values observed over Moscow during this specific period.

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