"ACE 1, Leg 1:   PMEL 2-stage impactor samples collected onboard the Discoverer for gravimetric analysis."

This is the text descriptor file for data contained in the file  L1_2_GRV.csv.
These data are PRELIMINARY. They should not be used without first contacting Trish Quinn (quinn@pmel.noaa.gov).

The gravimetrically-determined mass concentrations are given in ug/m3.  Submicron values represent the mass concentration in all particles
with aerodynamic diameters < 1.0 um.  Supermicron values are for particles with aerodynamic diameters
> 1um and < 10 um.  Diameters are given for the relative humidity of the sampled air stream.

(These diameters are given for a flow rate of 30 lpm and are subject to change after calibration of the 
collection efficiency of the impactor jet plate.  This calibration is planned for the Fall of 1996).

Uncertainties associated with the mass concentrations range from +/- 5 to 25%.

Columns in the spreadsheet are:

"1, Sample number"
"2, Start time,  GMT"
"3, Stop time,  GMT"
"4, Start Latitude"
"5, Stop Latitude"
"6, Start Longitude"
"7, Stop Longitude"
"8, average % RH of the sampled air stream."
"9, standard deviation of the RH of the sampled air stream."
"10,  % RH of the substrate during the pre-sampling weighing."
"11, % RH of the substrate during the post-sampling weighing."
"12, volume of sample (m3 of air)"
"13, sub_mass, submicron mass concentration in ug/m3"
"14, sup_mass, supermicron mass concentration in ug/m3"

Codes used in the file:

"NA, not available"