scholarly journals Intercomparison of lidar, aircraft, and surface ozone measurements in the San Joaquin Valley during the California Baseline Ozone Transport Study (CABOTS)

2018 ◽  
Author(s):  
Andrew O. Langford ◽  
Raul J. Alvarez ◽  
Guillaume Kirgis ◽  
Christoph J. Senff ◽  
Dani Caputi ◽  
...  
Keyword(s):  
Surface Ozone ◽  
San Joaquin Valley ◽  
Data Sets ◽  
Airborne Measurements ◽  
Transport Study ◽  
Research Aircraft ◽  
Surface Measurements ◽  
Ozone Transport ◽  
The University

Abstract. The California Baseline Ozone Transport Study (CABOTS) was conducted in the late spring and summer of 2016 to investigate the influence of long-range transport and stratospheric intrusions on surface ozone (O3) concentrations in California with emphasis on the San Joaquin Valley (SJV), one of two extreme ozone non-attainment areas in the U.S. One of the major objectives of CABOTS was to characterize the vertical distribution of O3 and aerosols above the SJV to aid in the identification of elevated transport layers and assess their surface impacts. To this end, the NOAA Earth System Research Laboratory (ESRL) deployed the Tunable Optical Profiler for Aerosol and oZone (TOPAZ) mobile lidar to the Visalia Municipal Airport (36.315° N, −119.392° E) in the central SJV between 27 May and 7 August 2016. Here we compare the TOPAZ ozone and backscatter measurements with co-located in-situ surface measurements and nearby regulatory monitors, and to airborne measurements from the University of California at Davis/Scientific Aviation Mooney and NASA Alpha Jet Atmospheric eXperiment (AJAX) research aircraft. Our analysis shows excellent agreement between the lidar and in-situ measurements, lending confidence to the use of these data sets for more detailed analyses.

scholarly journals Intercomparison of lidar, aircraft, and surface ozone measurements in the San Joaquin Valley during the California Baseline Ozone Transport Study (CABOTS)

2019 ◽  
Vol 12 (3) ◽  
pp. 1889-1904 ◽  
Author(s):  
Andrew O. Langford ◽  
Raul J. Alvarez II ◽  
Guillaume Kirgis ◽  
Christoph J. Senff ◽  
Dani Caputi ◽  
...  
Keyword(s):  
Surface Ozone ◽  
San Joaquin Valley ◽  
Transport Study ◽  
The Us ◽  
Range Transport ◽  
Research Aircraft ◽  
Surface Measurements ◽  
Ozone Transport ◽  
The University

Abstract. The California Baseline Ozone Transport Study (CABOTS) was conducted in the late spring and summer of 2016 to investigate the influence of long-range transport and stratospheric intrusions on surface ozone (O3) concentrations in California with emphasis on the San Joaquin Valley (SJV), one of two extreme ozone non-attainment areas in the US. One of the major objectives of CABOTS was to characterize the vertical distribution of O3 and aerosols above the SJV to aid in the identification of elevated transport layers and assess their surface impacts. To this end, the NOAA Earth System Research Laboratory (ESRL) deployed the Tunable Optical Profiler for Aerosol and oZone (TOPAZ) mobile lidar to the Visalia Municipal Airport (36.315∘ N, 119.392∘ E) in the central SJV between 27 May and 7 August 2016. Here we compare the TOPAZ ozone retrievals with co-located in situ surface measurements and nearby regulatory monitors and also with airborne in situ measurements from the University of California at Davis–Scientific Aviation (SciAv) Mooney and NASA Alpha Jet Atmospheric eXperiment (AJAX) research aircraft. Our analysis shows that the lidar and aircraft measurements agree, on average to within 5 ppbv, the sum of their stated uncertainties of 3 and 2 ppbv, respectively.

scholarly journals Entrainment and Mixing of Transported Ozone Layers: Implications for Surface Air Quality in the Western U.S.

2020 ◽  
Vol 237 ◽  
pp. 03012
Author(s):  
Christoph Senff ◽  
Andrew Langford ◽  
Raul Alvarez ◽  
Tim Bonin ◽  
Alan Brewer ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Quality ◽  
Mixed Layer ◽  
Las Vegas ◽  
Surface Ozone ◽  
Ground Level ◽  
San Joaquin Valley ◽  
Fire Emissions ◽  
Ozone Transport ◽  
The Impact

Recently, two air quality campaigns were conducted in the southwestern United States to study the impact of transported ozone, stratospheric intrusions, and fire emissions on ground-level ozone concentrations. The California Baseline Ozone Transport Study (CABOTS) took place in May – August 2016 covering the central California coast and San Joaquin Valley, and the Fires, Asian, and Stratospheric Transport Las Vegas Ozone Study (FAST-LVOS) was conducted in the greater Las Vegas, Nevada area in May – June 2017. During these studies, nearly 1000 hours of ozone and aerosol profile data were collected with the NOAA TOPAZ lidar. A Doppler wind lidar and a radar wind profiler provided continuous observations of atmospheric turbulence, horizontal winds, and mixed layer height. These measurements allowed us to directly observe the degree to which ozone transport layers aloft were entrained into the boundary layer and to quantify the resulting impact on surface ozone levels. Mixed layer heights in the San Joaquin Valley during CABOTS were generally below 1 km above ground level (AGL), while boundary layer heights in Las Vegas during FAST-LVOS routinely exceeded 3 km AGL and occasionally reached up to 4.5 km AGL. Consequently, boundary layer entrainment was more often observed during FAST-LVOS, while most elevated ozone layers passed untapped over the San Joaquin Valley during CABOTS.

scholarly journals Airborne Spectral Measurements of Ocean Directional Reflectance

2005 ◽  
Vol 62 (4) ◽  
pp. 1072-1092 ◽  
Author(s):  
Charles K. Gatebe ◽  
Michael D. King ◽  
Alexei I. Lyapustin ◽  
G. Thomas Arnold ◽  
Jens Redemann
Keyword(s):  
Wind Speed ◽  
Transfer Problem ◽  
Strong Dependence ◽  
Radiative Transfer Problem ◽  
Airborne Measurements ◽  
Wind Speeds ◽  
Research Aircraft ◽  
Low Wind Speeds ◽  
The University ◽  
Bidirectional Reflectance Distribution

Abstract The Cloud Absorption Radiometer (CAR) was flown aboard the University of Washington Convair 580 (CV-580) research aircraft during the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign and obtained measurements of bidirectional reflectance distribution function (BRDF) of the ocean in July and August 2001 under different illumination conditions with solar zenith angles ranging from 15° to 46°. The BRDF measurements were accompanied by concurrent measurements of atmospheric aerosol optical thickness and column water vapor above the airplane. The method of spherical harmonics with Cox–Munk wave-slope distribution is used in a new algorithm developed for this study to solve the atmosphere–ocean radiative transfer problem and to remove the effects of the atmosphere from airborne measurements. The algorithm retrieves simultaneously the wind speed and full ocean BRDF (sun’s glitter and water-leaving radiance) from CAR measurements and evaluates total albedo and equivalent albedo for the water-leaving radiance outside the glitter. Results show good overall agreement with other measurements and theoretical simulations, with the anisotropy of the water-leaving radiance clearly seen. However, the water-leaving radiance does not show a strong dependence on solar zenith angle as suggested by some theoretical studies. The spectral albedo was found to vary from 4.1%–5.1% at λ = 0.472 μm to 2.4%–3.5% for λ ≥ 0.682 μm. The equivalent water-leaving albedo ranges from 1.0%–2.4% at λ = 0.472 μm to 0.1%–0.6% for λ = 0.682 μm and 0.1%–0.3% for λ = 0.870 μm. Results of the validation of the Cox–Munk model under the conditions measured show that although the model reproduces the shape of sun’s glitter on average with an accuracy of better than 30%, it underestimates the center of the sun’s glitter reflectance by about 30% for low wind speeds (<2–3 m s−1). In cases of high wind speed, the model with Gram–Charlier expansion seems to provide the best fit.

scholarly journals Transport of aerosol to the Arctic: analysis of CALIOP and French aircraft data during the spring 2008 POLARCAT campaign

2014 ◽  
Vol 14 (16) ◽  
pp. 8235-8254 ◽  
Author(s):  
G. Ancellet ◽  
J. Pelon ◽  
Y. Blanchard ◽  
B. Quennehen ◽  
A. Bazureau ◽  
...  
Keyword(s):  
Calibration Procedure ◽  
Airborne Lidar ◽  
The Arctic ◽  
Orthogonal Polarization ◽  
Transport Pathways ◽  
Airborne Measurements ◽  
Surface Measurements ◽  
Regional Analyses ◽  
532 Nm

Abstract. Lidar and in situ observations performed during the Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, Climate, Chemistry, Aerosols and Transport (POLARCAT) campaign are reported here in terms of statistics to characterize aerosol properties over northern Europe using daily airborne measurements conducted between Svalbard and Scandinavia from 30 March to 11 April 2008. It is shown that during this period a rather large number of aerosol layers was observed in the troposphere, with a backscatter ratio at 532 nm of 1.2 (1.5 below 2 km, 1.2 between 5 and 7 km and a minimum in between). Their sources were identified using multispectral backscatter and depolarization airborne lidar measurements after careful calibration analysis. Transport analysis and comparisons between in situ and airborne lidar observations are also provided to assess the quality of this identification. Comparison with level 1 backscatter observations of the spaceborne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) were carried out to adjust CALIOP multispectral observations to airborne observations on a statistical basis. Recalibration for CALIOP daytime 1064 nm signals leads to a decrease of their values by about 30%, possibly related to the use of the version 3.0 calibration procedure. No recalibration is made at 532 nm even though 532 nm scattering ratios appear to be biased low (−8%) because there are also significant differences in air mass sampling between airborne and CALIOP observations. Recalibration of the 1064 nm signal or correction of −5% negative bias in the 532 nm signal both could improve the CALIOP aerosol colour ratio expected for this campaign. The first hypothesis was retained in this work. Regional analyses in the European Arctic performed as a test emphasize the potential of the CALIOP spaceborne lidar for further monitoring in-depth properties of the aerosol layers over Arctic using infrared and depolarization observations. The CALIOP April 2008 global distribution of the aerosol backscatter reveal two regions with large backscatter below 2 km: the northern Atlantic between Greenland and Norway, and northern Siberia. The aerosol colour ratio increases between the source regions and the observations at latitudes above 70° N are consistent with a growth of the aerosol size once transported to the Arctic. The distribution of the aerosol optical properties in the mid-troposphere supports the known main transport pathways between the mid-latitudes and the Arctic.

scholarly journals Atmospheric aerosol, gases and meteorological parameters measured during the LAPSE-RATE campaign

2020 ◽  
Author(s):  
David Brus ◽  
Jani Gustafsson ◽  
Osku Kempinen ◽  
Gijs de Boer ◽  
Anne Hirsikko
Keyword(s):  
Meteorological Parameters ◽  
Lower Atmosphere ◽  
Lapse Rate ◽  
Unmanned Aerial Systems ◽  
Data Sets ◽  
Finnish Meteorological Institute ◽  
Airborne Measurements ◽  
Surface Measurements ◽  
Kansas State University ◽  
Community Archive

Abstract. Small Unmanned Aerial Systems (sUAS) are becoming very popular as affordable and reliable observation platforms. The Lower Atmospheric Process Studies at Elevation - a Remotely-piloted Aircraft Team Experiment (LAPSE-RATE), conducted in the San Luis Valley of Colorado (USA) between July 14th – 20th, 2018, gathered together numerous sUAS, remote sensing equipment and ground based instrumentation. Flight teams from the Finnish Meteorological Institute and the Kansas State University co-operated during LAPSE-RATE to measure and investigate the properties of aerosol particles and gases at the surface and in the lower atmosphere. During LAPSE-RATE the deployed instrumentation operated reliably, resulting in a scientifically sound observational dataset. Our observations included aerosol particle number concentrations and size distributions, concentrations of CO2 and water vapor, and meteorological parameters. All data sets have been uploaded to the Zenodo LAPSE-RATE community archive (https://zenodo.org/communities/lapse-rate/). The dataset DOIs for FMI airborne measurements and surface measurements are available here: https://doi.org/10.5281/zenodo.3993996, Brus et al. (2020a), and for KSU airborne measurements and surface measurements are available here: https://doi.org/10.5281/zenodo.3736772, Brus et al. (2020b).

Investigation of transport in the northern lowermost stratosphere between spring and fall using airborne in situ tracer measurements

2020 ◽  
Author(s):  
Andrea Rau ◽  
Valentin Lauther ◽  
Johannes Wintel ◽  
Emil Gehardt ◽  
Peter Hoor ◽  
...  
Keyword(s):  
Time Scales ◽  
Asian Monsoon ◽  
Lagrangian Model ◽  
Mixing Ratios ◽  
Tropical Tropopause ◽  
Research Aircraft ◽  
Transport And Mixing ◽  
The University

<p>Over the course of the summer, when the subtropical jet is weakest, quasi-isentropic transport of young air from the troposphere and the tropical tropopause layer into the northern hemisphere (NH) lowermost stratosphere (LMS) is increased resulting in a drastic change of LMS chemical composition between spring and fall. The focus of this work is on the role of different transport paths into the NH LMS, including outflow from the Asian Monsoon, and their associated time scales of transport and mixing.<br><br>We present and analyse in situ measurements of CO<sub>2</sub> and various long-lived tracers obtained during three recent aircraft campaigns encompassing over 40 research flights in the NH UTLS during winter/spring, summer, and fall. The POLSTRACC/GW-LCYCLE/SALSA campaign probed the northern high latitude LMS in winter/spring 2016, deploying the German research aircraft HALO from Kiruna (Sweden) and from Germany. The second campaign deployed the M55 Geophysica research aircraft in July/August 2017 from Kathmandu, Nepal, in the frame of the EU-funded project StratoClim (Stratospheric and upper tropospheric processes for better Climate predications) in order to probe in situ for the first time the inside of the Asian Monsoon anticyclone. Roughly two months later the WISE (Wave-driven ISentropic Exchange) campaign deployed again HALO from Shannon (Ireland) in September and October 2017 to investigate isentropic transport and mixing in the NH LMS.<br><br>The University of Wuppertal measured CO<sub>2</sub> and a suite of long-lived tracers on each aircraft. On the Geophysica, the measurements were made with the HAGAR (High Altitude Gas AnalyzeR) instrument. On HALO, a recently developed extended 5-channel version, HAGAR-V, was flown, which in addition measured a suite of short-lived tracers by GC coupled with a mass spectrometer. The University of Mainz measured N2O and CO on HALO using laser absorption techniques. For our analysis we use mixing ratios of CO<sub>2</sub>, SF<sub>6</sub>, CFC-11, CFC-12, and N<sub>2</sub>O.<br><br>Owing to their different lifetimes, tropospheric growth (for SF<sub>6</sub>) and a seasonal cycle (for CO<sub>2</sub>), the LMS distributions of these long-lived trace gases and their development between spring and fall contain key information about the origin and mean stratospheric age of LMS air as well as time scales of rapid isentropic transport and mixing. The analysis of tracer measurements is complemented by simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) providing information on age of air spectra and fractions of origin from specific surface regions, allowing in particular to assess the role of the Asian Monsoon in determining the composition of the NH LMS in fall.</p>

scholarly journals Inter-comparison of snow depth over sea ice from multiple methods

2020 ◽  
Author(s):  
Lu Zhou ◽  
Julienne Stroeve ◽  
Shiming Xu ◽  
Alek Petty ◽  
Rachel Tilling ◽  
...  
Keyword(s):  
Sea Ice ◽  
Snow Depth ◽  
Ground Truth ◽  
Significant Trend ◽  
Data Sets ◽  
Snow Density ◽  
Spatial And Temporal Scales ◽  
Danish Meteorological Institute ◽  
The University

Abstract. In this study, we compare eight recently developed snow depth products that use satellite observations, modeling or a combination of satellite and modeling approaches. These products are further compared against various ground-truth observations, including those from ice mass balance buoys (IMBs), snow buoys, snow depth derived from NASA's Operation IceBridge (OIB) flights, as well as snow depth climatology from historical observations. Large snow depth discrepancies between the different snow depth data sets are observed over the Atlantic and Canadian Arctic sectors. Among the products evaluated, the University of Washington snow depth product (UW) produces the overall deepest spring (March-April) snow packs, while the snow product from the Danish Meteorological Institute (DMI) provide the shallowest spring snow depths. There is no significant trend in the mean snow depth among all snow products since the 2000s, despite the great differences in regional snow depth. Two products, SnowModel-LG and the NASA Eulerian Snow on Sea Ice Model (NESOSIM), also provide estimates of snow density. Arctic-wide, these density products show the expected seasonal evolution with varying inter-annual variability, and no significant trend since the 2000s. The snow density in SnowModel-LG is generally higher than climatology, whereas NESOSIM density is generally lower. Both SnowModel-LG and NESOSIM densities have a larger seasonal change than climatology. Inconsistencies in the reconstructed snow parameters among the products, as well as differences between in-situ and airborne observations can in part be attributed to differences in effective footprint and spatial/temporal coverage, as well as insufficient observations for validation/bias adjustments. Our results highlight the need for more targeted Arctic surveys over different spatial and temporal scales to allow for a more systematic comparison and fusion of airborne, in-situ and remote sensing observations.

Inter-comparison of snow depth over sea ice from multiple methods

2020 ◽  
Author(s):  
Lu Zhou ◽  
Julienne Stroeve ◽  
Shiming Xu
Keyword(s):  
Sea Ice ◽  
Snow Depth ◽  
Ground Truth ◽  
Significant Trend ◽  
Data Sets ◽  
Snow Density ◽  
Spatial And Temporal Scales ◽  
Danish Meteorological Institute ◽  
The University

<p>In this study, we compare eight recently developed snow depth products that use satellite observations, modeling or a combination of satellite and modeling approaches. These products are further compared against various ground-truth observations, including those from ice mass balance buoys (IMBs), snow buoys, snow depth derived from NASA's Operation IceBridge (OIB) flights, as well as snow depth climatology from historical observations.</p><p>Large snow depth differences between data sets are observed over the Atlantic and Canadian Arctic sectors. Among the products evaluated, the University of Washington snow depth product (UW) produces the overall deepest Spring snow packs, while the snow product from the Danish Meteorological Institute (DMI) provide the shallowest Spring snow depths. There is no significant trend for mean snow depth among all snow products since the 2000s, however, those in regional varies larhely. Two products, SnowModel-LG and the NASA Eulerian Snow on Sea Ice Model: NESOSIM, also provide estimates of snow density. Arctic-wide, these density products show the expected seasonal evolution with varying inter-annual variability, and no significant trend since the 2000s. Compared to climatology, snow density from SnowModel-LG is generally denser, whereas that from NESOSIM is less. Both SnowModel-LG and NESOSIM densities have a larger seasonal change than climatology.</p><p>Inconsistencies in the reconstructed snow parameters among the products, as well as differences and with in-situ and airborne observations can in part be attributed to differences in effective footprint and spatial/temporal coverage, as well as insufficient observations for validation/bias adjustments. Our results highlight the need for more targeted Arctic surveys over different spatial and temporal scales to allow for a more systematic comparison and fusion of airborne, in-situ and remote sensing observations.</p>

Mobile MAX-DOAS and in situ measurements of atmospheric trace gases and aerosols

2020 ◽  
Author(s):  
Folkard Wittrock ◽  
Kai Krause ◽  
Kezia Lange ◽  
André Seyler ◽  
Andreas Richter ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Trace Gases ◽  
Data Sets ◽  
Atmospheric Trace Gases ◽  
Life Project ◽  
Marine Traffic ◽  
Set Up ◽  
The University ◽  
Mobile Measurements

<p>As part of the German project MeSMarT (Measurements of shipping emissions in the marine troposphere, a cooperation between the University of Bremen and the German Federal Maritime and Hydrographic Agency) and the EU LIFE project CLINSH (Clean Inland Shipping,) numerous mobile measurements of atmospheric trace gases and aerosols have been carried out.</p><p>For both projects one main objective is to investigate the general impact of shipping emissions on the air quality in regions with high marine traffic. In order to do this in areas where no permanent monitoring systems are available, in 2015 a mobile lab has been set up, which includes among other instrumentation for air pollution and meteorological parameters a scientific-grade MAX-DOAS system as well as in situ instruments for nitrogen oxides, ozone, carbon monoxide and sulfur dioxide (trace level).</p><p>In this study we present intercomparison results between the different instruments onboard the mobile lab as well as the interpretation of the results using complementary data sets at different locations including the Lower Rhine and Waal area and several regions in Northern Germany. For some places close to the banks of the Rhine more than 70% of the nitrogen oxides are related to shipping emissions. Emission factors for different ship types have been calculated and compared to recent studies and emission inventories.</p>

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