Airborne Lidar Plume and Haze Analyzer (ALPHA-1)

1980 ◽  
Vol 61 (9) ◽  
pp. 1035-1043 ◽  
Author(s):  
Edward E. Uthe ◽  
Norman B. Nielsen ◽  
Walter L. Jimison
Keyword(s):  
Boundary Layer ◽  
Los Angeles ◽  
Power Plants ◽  
Particle Concentration ◽  
Layer Structure ◽  
Airborne Lidar ◽  
Test Program ◽  
Lidar System ◽  
Four Corners ◽  
Terrain Features

A new two-wavelength airborne lidar system has been constructed and field-tested. The system was designed to observe the distribution of particle concentrations over large regional areas. During a one-week field-test program, the system was used to observe boundary layer structure over the Los Angeles area and the downwind structure of particulate plumes from the Navajo (Page, Ariz.) and Four Corners (Farmington, N.Mex.) power plants. Data examples presented show the importance of terrain features in influencing particle concentration distributions over regional areas.

scholarly journals Effects of model resolution on the interpretation of satellite NO<sub>2</sub> observations

2011 ◽  
Vol 11 (22) ◽  
pp. 11647-11655 ◽  
Author(s):  
L. C. Valin ◽  
A. R. Russell ◽  
R. C. Hudman ◽  
R. C. Cohen
Keyword(s):  
New Mexico ◽  
Los Angeles ◽  
Power Plants ◽  
Loss Rate ◽  
Nonlinear Effects ◽  
Model Resolution ◽  
Transport Models ◽  
Chemical Transport Models ◽  
Four Corners ◽  
Tropospheric No2

Abstract. Inference of NOx emissions (NO+NO2) from satellite observations of tropospheric NO2 column requires knowledge of NOx lifetime, usually provided by chemical transport models (CTMs). However, it is known that species subject to non-linear sources or sinks, such as ozone, are susceptible to biases in coarse-resolution CTMs. Here we compute the resolution-dependent bias in predicted NO2 column, a quantity relevant to the interpretation of space-based observations. We use 1-D and 2-D models to illustrate the mechanisms responsible for these biases over a range of NO2 concentrations and model resolutions. We find that predicted biases are largest at coarsest model resolutions with negative biases predicted over large sources and positive biases predicted over small sources. As an example, we use WRF-CHEM to illustrate the resolution necessary to predict 10 AM and 1 PM NO2 column to 10 and 25% accuracy over three large sources, the Four Corners power plants in NW New Mexico, Los Angeles, and the San Joaquin Valley in California for a week-long simulation in July 2006. We find that resolution in the range of 4–12 km is sufficient to accurately model nonlinear effects in the NO2 loss rate.

scholarly journals Inter-comparison of lidar and ceilometer retrievals for aerosol and Planetary Boundary Layer profiling over Athens, Greece

2011 ◽  
Vol 4 (1) ◽  
pp. 73-99 ◽  
Author(s):  
G. Tsaknakis ◽  
A. Papayannis ◽  
P. Kokkalis ◽  
V. Amiridis ◽  
H. D. Kambezidis ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Layer Structure ◽  
Saharan Dust ◽  
Radiosonde Data ◽  
Backscatter Coefficient ◽  
Lidar System ◽  
Height Range ◽  
Tropospheric Aerosol ◽  
Filter Radiometer

Abstract. This study presents an inter-comparison of two active remote sensors (lidar and ceilometer) in determining the structure of the Planetary Boundary Layer (PBL) and in retrieving tropospheric aerosol vertical profiles over Athens, Greece. This inter-comparison was performed under various strongly different aerosol concentrations (urban air pollution, biomass burning and Saharan dust event), implementing two different lidar systems (one portable Raymetrics S.A. lidar system running at 355 nm and one multi-wavelength Raman lidar system running at 355 nm, 532 nm and 1064 nm) and one CL31 Vaisala S.A. ceilometer (running at 910 nm). To convert the ceilometer data to data having the same wavelengths as those from the lidar, the backscatter-related Ångström exponent was estimated using ultraviolet multi-filter radiometer (UV-MFR) data. The inter-comparison was based on two parameters: the mixing layer structure and height determined by the presence of the suspended aerosols and the aerosol backscatter coefficient. Additionally, radiosonde data were used to derive the PBL height. In general a good agreement is found between the ceilometer and the lidar techniques in both inter-compared parameters in the height range from 500 m to 5000 m, while the limitations of each instrument are also examined.

Development and Application of a Compact, Tunable, Solid-State Airborne Ozone Lidar System for Boundary Layer Profiling

2011 ◽  
Vol 28 (10) ◽  
pp. 1258-1272 ◽  
Author(s):  
R. J. Alvarez ◽  
C. J. Senff ◽  
A. O. Langford ◽  
A. M. Weickmann ◽  
D. C. Law ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Quality ◽  
Lower Troposphere ◽  
Companion Paper ◽  
Horizontal Resolution ◽  
Airborne Lidar ◽  
Laser Source ◽  
Atmospheric Conditions ◽  
Lidar System ◽  
Advanced Analysis

Abstract The National Oceanic and Atmospheric Administration/Earth System Research Laboratory/Chemical Sciences Division (NOAA/ESRL/CSD) has developed a versatile, airborne lidar system for measuring ozone and aerosols in the boundary layer and lower free troposphere. The Tunable Optical Profiler for Aerosol and Ozone (TOPAZ) lidar was deployed aboard a NOAA Twin Otter aircraft during the Texas Air Quality Study (TexAQS 2006) and the California Research at the Nexus of Air Quality and Climate Change (CalNex 2010) field campaigns. TOPAZ is capable of measuring ozone concentrations in the lower troposphere with uncertainties of several parts per billion by volume at 90-m vertical and 600-m horizontal resolution from an aircraft flying at 60 m s−1. The system also provides uncalibrated aerosol backscatter profiles at 18-m vertical and 600-m horizontal resolution. TOPAZ incorporates state-of-the-art technologies, including a cerium-doped lithium calcium aluminum fluoride (Ce:LiCAF) laser, to make it compact and lightweight with low power consumption. The tunable, three-wavelength UV laser source makes it possible to optimize the wavelengths for differing atmospheric conditions, reduce the interference from other atmospheric constituents, and implement advanced analysis techniques. This paper describes the TOPAZ lidar, its components and performance during testing and field operation, and the data analysis procedure, including a discussion of error sources. The performance characteristics are illustrated through a comparison between TOPAZ and an ozonesonde launched during the TexAQS 2006 field campaign. A more comprehensive set of comparisons with in situ measurements during TexAQS 2006 and an assessment of the TOPAZ accuracy and precision are presented in a companion paper.

scholarly journals Meteorological Model Evaluation for CalNex 2010

2012 ◽  
Vol 140 (12) ◽  
pp. 3885-3906 ◽  
Author(s):  
Wayne M. Angevine ◽  
Lee Eddington ◽  
Kevin Durkee ◽  
Chris Fairall ◽  
Laura Bianco ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Los Angeles ◽  
Land Surface ◽  
Layer Structure ◽  
Sea Breeze ◽  
San Joaquin Valley ◽  
Meteorological Model ◽  
Simulation Performance ◽  
Wind Speeds

Abstract The performance of mesoscale meteorological models is evaluated for the coastal zone and Los Angeles area of Southern California, and for the San Joaquin Valley. Several configurations of the Weather Research and Forecasting Model (WRF) with differing grid spacing, initialization, planetary boundary layer (PBL) physics, and land surface models are compared. One configuration of the Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS) model is also included, providing results from an independent development and process flow. Specific phenomena of interest for air quality studies are examined. All model configurations are biased toward higher wind speeds than observed. The diurnal cycle of wind direction and speed (land–sea-breeze cycle) as modeled and observed by a wind profiler at Los Angeles International Airport is examined. Each of the models shows different flaws in the cycle. Soundings from San Nicolas Island, a case study involving the Research Vessel (R/V) Atlantis and the NOAA P3 aircraft, and satellite images are used to evaluate simulation performance for cloudy boundary layers. In a case study, the boundary layer structure over the water is poorly simulated by all of the WRF configurations except one with the total energy–mass flux boundary layer scheme and ECMWF reanalysis. The original WRF configuration had a substantial bias toward low PBL heights in the San Joaquin Valley, which are improved in the final configuration. WRF runs with 12-km grids have larger errors in wind speed and direction than those present in the 4-km grid runs.

scholarly journals Effects of model spatial resolution on the interpretation of satellite NO<sub>2</sub> observations

2011 ◽  
Vol 11 (7) ◽  
pp. 20245-20265 ◽  
Author(s):  
L. C. Valin ◽  
A. R. Russell ◽  
R. C. Hudman ◽  
R. C. Cohen
Keyword(s):  
New Mexico ◽  
Los Angeles ◽  
Power Plants ◽  
Chemical Transport ◽  
Linear Process ◽  
Ozone Production ◽  
Transport Models ◽  
Chemical Transport Models ◽  
Four Corners ◽  
Non Linear

Abstract. Prediction of ozone production, a photochemically non-linear process, is known to be biased in coarse-resolution chemical transport models (CTM). Other species subject to non-linear sources or sinks are also susceptible. Here we compute the resolution-dependent bias in predicted NO2 column, a quantity relevant to the interpretation of space-based observations. We use 1-D and 2-D models to illustrate the mechanisms responsible for these biases over a range of NO2 concentrations and model resolutions. We find that the behavior of calculated biases in NO2 depends on the magnitude and spatial extent of the NO2 source. We use WRF-CHEM to determine the resolution necessary to predict column NO2 to 10 % and 25 % over the Four Corners power plants in NW New Mexico, Los Angeles, and the San Joaquin Valley in California.

scholarly journals Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign

2015 ◽  
Vol 28 (6) ◽  
pp. 2420-2442 ◽  
Author(s):  
Xiaoli Zhou ◽  
Pavlos Kollias ◽  
Ernie R. Lewis
Keyword(s):  
Boundary Layer ◽  
Los Angeles ◽  
Marine Boundary Layer ◽  
Layer Structure ◽  
Potential Temperature ◽  
Dominant Factor ◽  
Atmospheric Conditions ◽  
Field Campaign ◽  
Strong Inversion ◽  
Synoptic Conditions

Abstract The recent ship-based Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds (MAGIC) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporated before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models.

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