GRIP Langley Aerosol Research Group Experiment (LARGE)

Table of Contents

Introduction

Langley Aerosol Research Group Experiment (LARGE) was an aerosol measurement experiment conducted from the NASA DC-8 aircraft during the GRIP 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 Genesis and Rapid Intensification Processes (GRIP) experiment was a NASA Earth science field experiment conducted August 5 to September 30, 2010. The major goal was to better understand how tropical storms form and develop into major hurricanes. NASA used the DC-8 aircraft, the WB-57 aircraft and the Global Hawk Unmanned Airborne System (UAS), configured with a suite of in situ and remote sensing instruments that were used to observe and characterize the lifecycle of hurricanes. This campaign also capitalized on a number of ground networks and space-based assets, in addition to the instruments deployed on aircraft from Ft. Lauderdale, Florida ( DC-8), Houston, Texas (WB-57), and NASA Dryden Flight Research Center, California (Global Hawk). More information about this Campaign can be found on the GRIP web site: http://grip.nsstc.nasa.gov/

Aerodynamic 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
9.99 × 104 particles/cm3.

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.

These example data files are available for all the DC-8 flight days during the campaign:

GRIP_LARGE_yyyymmdd_aps_ambPT_rx.csv
GRIP_LARGE_yyyymmdd_uhsas_anbPT_rx.csv
GRIP_LARGE_yyyymmdd_optical_ambPT_rx.csv
GRIP_LARGE_yyyymmdd_cn_ambPT_rx.csv

where,

GRIP = the campaign name
LARGE = the dataset name - Langley Aerosol Research Group Experiment (LARGE)
yyyymmdd = the year, month and day of the data
aps = Aerodynamic Particle Sizer
optical = Optical Particle Counter
uhsas = Ultra-High Sensitivity Aerosol Spectrometer
cn = Condensation Nuclei Counter
rx = the data revision number
csv = Comma Separated Values format

The LARGE data files are ASCII text, in Comma Separated Values format (csv). This file type is easily imported into a spreadsheet, such as Microsoft Excel.

The data is arranged according to flights which are mapped to days. Table 1 contains the day to flight mapping.

TABLE 1. Day to Flight Mapping

The data producer has supplied informative readme files for each data type. These files can be read or downloaded here:

GRIP_large_APS_readme.txt
GRIP_large_CNC_readme.txt
GRIP_large_OPC_readme.txt
GRIP_large_OPT_readme.txt
GRIP_large_UHSAS_readme.txt

The data producers (PIs) are:

Bruce Anderson and Gao Chen
MS 483, NASA Langley Research Center
Hampton VA
b.e.anderson@larc.nasa.gov
gao.chen1@nasa.gov

The data contact is:

Lee Thornhill
MS 483, NASA Langley Research Center
Hampton VA
Kenneth.L.Thornhill@nasa.gov

To order these data or for further information, please contact:

Global Hydrology Resource Center
User Services
320 Sparkman Drive
Huntsville, AL 35805
Phone: 256-961-7932
E-mail: support-ghrc@earthdata.nasa.gov
Web: http://ghrc.nsstc.nasa.gov/