MAARCO: The Mobile Atmospheric Aerosol and

Radiation Characterization Observatory

The Naval Research Laboratory-Monterey (NRL-MRY) has developed a mobile, surface observatory. MAARCO (Fig. 1) is a specially designed, climate-controlled sea-container outfitted with a unique and comprehensive suite of instruments to measure the radiometric and meteorological properties of the atmosphere at the surface, the vertical distribution of aerosols and clouds, and the microphysical and compositional properties of aerosols at the surface. Table 1 lists the full complement of MAARCO instruments. The potential of MAARCO can only be fully achieved when staffed by scientists that understand the fundamental principles behind each of the instruments. Code 7544 has this expertise and has proven it in numerous field programs. In the past 5 years members of the group have participated in 12 aerosol and radiation field programs. In the past two years alone, the group has authored 9 peer-reviewed publications on dust and 8 more on aerosols.

Figure 1: MAARCO on site at NRL-MRY with external instrumentation identified

Two important components of MAARCO are the Micro Pulse Lidar, which is part of NASA Goddard’s MPL Net (http://mplnet.gsfc.nasa.gov/), a growing worldwide network of aerosol/cloud lidars, and the Cimel Sun Photometer, which is part of the NASA Goddard AERONET (http://aeronet.gsfc.nasa.gov/), a worldwide network of aerosol sun photometers.

MAARCO currently is deployed on-site at NRL-MRY (latitude: 36°35.503` N, longitude: 121°51.236’ W, altitude @ 170 ft MSL), approximately a half mile from the Pacific coast and Monterey Bay and adjacent to the Monterey County Airport. During shipment, all of the external instrumentation and superstructures are removed and stored inside MAARCO. MAARCO has made continuous measurements since March 2003.

Table 1: MAARCO Instrumentation

Instrument	Manufacturer	Measurement	Specs

Radiation

Sun Photometer	Aeronet-Cimel	Aerosol optical thickness at given wavelengths	340, 380, 440, 500, 675, 870, 1020 nm
CM-22 Solar Broadband Radiometer	Kipp & Zonen	Total downwelling broadband solar flux	0.2 – 3.6 mm
Shaded CM-22 Solar Broadband Radiometer	Kipp & Zonen	Diffuse downwelling broadband solar flux	0.2 – 3.6 mm
CG-4 IR Broadband Radiometer	Kipp & Zonen	Downwelling broadband IR flux	4.5 – 42 mm
Shaded CG-4 IR Broadband Radiometer	Kipp & Zonen	Downwelling broadband IR flux with solar heating of the dome eliminated	4.5 – 42 mm
CH-1 Normal Incidence Pyrheliometer	Kipp & Zonen	Normal incidence direct solar radiation	0.2 – 4.0 mm
2AP-GD Solar Tracker	Kipp & Zonen	Provides high accuracy tracking of the sun for the CH-1 Pyrheliometer and solar shading for the CM22 and CG4 radiometers
Multi-Filter Rotating Shadowband Radiometer (MFRSR)	Yankee Environmental Systems	Total and diffuse solar flux at the given wavelengths from which direct solar flux and optical depth are obtained

Meteorology

TSI-440A Total Sky Imager	Yankee Environmental Systems	Automated, full sky color images for determining fractional cloud cover and sky conditions	352 x 288 color, 24 bit images. Maximum sampling rate of one image every 30 secs
ET106 Weather Station: CS500 Air Temperature and RH Sensor, TE525 Rain Gauge, 034A Wind Speed and Direction Sensor, LI200X Solar Radiation Sensor	Campbell Scientific	Air temperature, relative humidity, rainfall, wind speed and direction, and solar radiation	air temperature accuracy: +/- 1.5^oC RH accuracy: +/- 3% rainfall accuracy: +/- 1% solar radiation accuracy: +/- 5%
CS7500 Li-Cor L17500 Open-Path CO₂/H₂O Analyzer	Campbell Scientific	In situ densities of CO₂ and H₂O in turbulent air structures. When used in conjunction with the sonic anemometer measurements the fluxes of CO₂ and H₂O are obtained using the eddy covariance technique	12.5 cm open path, with single pass optics and 1 cm diameter optical beam. Reference filters at 3.95 mm and 2.40 mm. Absorption measured at 4.26 mm (CO₂) and 2.59 mm (H₂O)
FW05 Type E Fine Wire TC	Campbell Scientific	rapid response temperature probe for eddy correlation
CSAT3 3-D Sonic Anemometer	Campbell Scientific	Three orthogonal wind components, u_x, u_y, u_z, and the speed of sound	rate: 1-60 Hz resolution: u_x, u_y 1 mm/s rms; u_z 0.5 mm/s rms

Aerosol

Micro Pulse Lidar	NASA Goddard	Vertical distribution of aerosols and clouds	523.5 nm, eye-safe system
3-Wavelength Nephelometer	TSI	Extinction coefficient	450, 550, 700 nm
Aerodynamic Particle Sizer (APS)	TSI	particle size distribution	0.5mm < Dp < 20mm
TEOM Ambient Particulate Monitor	Rupprecht & Patashnick Co., Inc.	total aerosol mass	TSP
TECO Ozone Analyzer	TECO	O₃ concentration
TECO SO2 Analyzer	TECO	SO₂ concentration