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NAMMA Langley Aerosol Research Group Experiment (LARGE) Table of Contents
Langley Aerosol Research Group Experiment (LARGE) was an aerosol measurement experiment conducted from the NASA DC-8 aircraft during the NAMMA field campaign. This dataset consists of data collected from In situ aerosol sensors which include: condensation nuclei counters, optical particle spectrometers, an aerodynamic particle sizer, multi-wavelength particle-soot absorption photometers, and integrating nephelometers. The measurements made include: ultrafine aerosol number density, total and non-volatile aerosol number density, dry aerosol size distribution from 0.01 to 10 mm, total and submicron aerosol absorption coefficients at 470, 535, and 670 nm, total and submicron aerosol scattering coefficients at 550 nm, and total scattering and hemispheric backscattering coefficients at 400, 550 and 700 nm. Other derived data includes: aerosol size statistics (mode, number and mass mean diameters, etc.), aerosol surface area and mass loading, aerosol extinction, single scattering albedo, and angstrom coefficients. The LARGE QC Nav data (ICATS) is included with this dataset, and can be ordered seperately. This dataset has the following differences from the original ICATS data: Campaign These data files were generated during support of the NASA African Monsoon Multidisciplinary Analyses (NAMMA) campaign, a field research investigation sponsored by the Science Mission Directorate of the National Aeronautics and Space Administration (NASA). This mission was based in the Cape Verde Islands, 350 miles off the coast of Senegal in west Africa. Commencing in August 2006, NASA scientists employed surface observation networks and aircraft to characterize the evolution and structure of African Easterly Waves (AEWs) and Mesoscale Convective Systems over continental western Africa, and their associated impacts on regional water and energy budgets. For more information about the NAMMA Campaign, go to the NAMMA web site: http://namma.nsstc.nasa.gov/ Instrument DescriptionAerodynamic Particle Sizer (APS) The APS provides high-resolution, real-time aerodynamic measurements of particles from 0.5 to 20 µm, providing number-weighted, particle size distributions. The APS was the first instrument to measure aerodynamic diameter and light-scattering intensity simultaneously. TSI Condensation Nuclei Counters (CNC) Condensation nucleus (CN) concentrations were measured with TSI 3025 and 3010 CN counters (CNC) for particles with diameters greater than 3 and 10 nm, respectively. Concentrations of ultrafine particles can be determined by difference. Model 3010 The TSI model 3010 CNC is a compact, single-particle counting instrument used in a variety of applications. This partial counter measures the number concentration of individual particles that are 0.01 μm in diameter and larger. The particles are detected by condensing alcohol vapor onto the particles, causing them to grow into droplets. These particles, in droplet form, are easily counted by a simple optical particle detector requiring detection of particles 0.01 μm in diameter and larger. Model 3025 The TSI model 3025A uses a vapor sheath technique to improve the instrument’s lower particle size sensitivity. This means that the counter is capable of measuring the number concentration of submicrometer airborne particles that are larger than 3 nanometers in diameter. The particles are detected and counted by a simple optical detector after a supersaturated vapor condenses onto the particles, causing them to grow into larger droplets. The range of particle concentration detection extends from less than 0.01 particle/cm3 to Optical Particle Counter (OPC) The OPC is an in situ instrument which counts and sizes particles drawn into a sampling chamber. These instruments are sensitive to particles as small as 0.15 μm in radius. Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) This airborne optical spectrometer is an optical scattering, single-particle instrument. It measures aerosol particles in the range from 0.055 µm to 1 µm. TSI Nephelometer The TSI Incorporated Nephelometer is used to measure light scattering due to aerosol particles at red, green and blue wavelengths. The spectral channels of this instrument are 450, 550 and 700 nm. RR Nephelometer The Radiance Research M903 Nephelometer is used to measure light scattering due to aerosol particles at a green wavelength. Three identical instruments are installed to measure light scattering under three different relative humidity (RH) levels: dry, ambient and wet. These measurements are used to derive RH dependency of light scattering. The spectral channel of these instruments is 530nm. File Naming ConventionThese example data files are available for all the DC-8 flight days during the campaign:
where, Data Format These LARGE data files are ASCII text, in Comma Separated Values format (csv). These file types are easily imported into a spreadsheet, such as Microsoft Excel. The data producer has supplied informative readme files for each data type. These files can be read or downloaded here: Contact Information The data producer (PI) is:
The data contact is:
To order these data or for further information, please contact:
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