Instruments

Aircraft: Aerosols, trace gases and upper air meteorology (up to 3 km).

Ozonesondes: Ozone, relative humidity, and temperature in the vertical column (up to ~35 km).

Surface sites: Trace gases, chemical speciation and meteorological parameters (ground level measurements)








Aircraft

The sampling platform used for this research is a twin engine Piper Aztec research aircraft (owned and operated by University Research Foundation - Advanced Development Laboratory). The aircraft is outfitted with a suite of trace gas and aerosol instruments. As shown on the left, the inlets are engineered onto the upper fuselage. There is an aft-facing inlet plumbed to the trace gas instruments while a forward facing, isokinetic inlet feeds the aerosol instruments. Due to inlet sampling line losses of super-µ (diameter) particles, all measurements are of sub-µ particles only. A meteorological probe is nestled between these two inlets.

Aircraft Instruments
Parameter	Temporal Resolution	Detection Limit	Technique (Instrument)
Position	10 s	15 m	GPS (Garmin GPS90)
Static pressure	10 s	5 mbar	Transducer (Rosemont 1008)
Temperature	10 s	0.5 oC	Thermistor (Rustrack RR2-252)
Relative Humidity	10 s	2%	Thin capacitive film (Rustrack RR2-252)
U, V wind components	1 s	0.2 ms-1	Differential GPS (AIMMS-10)
O3	4 s	1 ppbv	UV photometry (TEI 49C)
NO2 ¶	TBD	TBD	Custom TDL/CDR sensor
NO	10 s	50 ppbv	O3 Chemiluminescence (modified TEI 42C)
CO	1 min *	20 ppbv	Modified NDIR/GFC (TEI 48C)
SO2	1 min *	30 pptv	Modified pulsed-fluorescence (TEI 43C)
Aerosol Absorption	1 min	0.9 x 106 m-1	Modified photometric (Radiance Research PSAP)
Aerosol Scattering	1 min	0.1-0.4 x 106m-1	Integrating Nephelometer (TSI 3563)
Particle counts	10 s	0.01 µm	Condensation Particle Counter Model 3007
Aerosol size (0.3-10 µm)	1 min	N/Aa	Custom laser based optical (Met One 9012)

^¶ Instrument under development at GWU/CHEM but likely available
* From 10 s data
^a Counts individual particles and uncertainty of particle number density within individual size bins, is controlled by poisson statistics and the uncertainty in the airflow rates

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Ozonesondes

Ozonesondes are launched during code-red events at a site in Beltsville, MD (39.054^o W, 76.877^o N). Launchings are held in conjuction with Howard University and NASA/GSFC. See Beltsville ozonesonde website for more details.

Ozonesonde Instruments
Parameter	Temporal Resolution	Detection Limit	Technique (Instrument)
O3	2 s	- ppmv	ECC ozonesonde
Relative Humidity	2 s	1 %	Vaisala RS-80
Temperature	2 s	0.1 oC	Vaisala RS-80
Pressure	2 s	0.1 hPa	Vaisala RS-80

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Surface Sites

Measurements have been taken at three sites (Wye River, Fort Meade, and Shenandoah National Park).

Ozonesonde Instruments
Parameter	Temporal Resolution	Detection Limit	Technique (Instrument)
Temperature	10 s	0.5 oC	Thermistor (Rustrack RR2-252)
Relative Humidity	10 s	2%	Thin capacitive film (Rustrack RR2-252)
U, V wind components	1 s	0.2 ms-1	Differential GPS (AIMMS-10)
Actinic flux	1 min	150 µV/ Wm-2	Eppley total ultraviolet radiometer
O3	1 min	1 ppbv	UV photometry
NOy	1 min	10 pptv	O3 Chemiluminescence (modified TEI 42C) and a molybdenum converter
NO	1 min	10 pptv	O3 Chemiluminescence (modified TEI 42C **)
CO	1 min	20 ppbv	Modified NDIR/GFC (43C)
SO2	1 min	30 pptv	Modified pulsed-fluorescence (TEI 43C)
Aerosol speciation	-	-	DRI sequential filter sampler

** At Wye River a modified TEI 14B is used instead