All of the aerosol data submitted has been corrected to Standard Temperature and Pressure (STP), with the 
exception of absorption,  scattering, and liquid water content (LWC).  See table 1) below for a complete list 
of submitted variables and whether they have been STP corrected or not.  This correction to STP was done 
for two main reasons:  
(1) Most gas phase measurements have been submitted as mixing ratios (similar to our STP correction)
(2) Our instruments are measuring at pressures and temperatures different from ambient conditions (due to 
RAM pressure increase and sampling at aircraft cabin temperature).

The correction was applied using the formula:
                        STP data = instrument data*(Standard P/Sample P)*(Sample T/Standard T)
                                                                   with Standard P=1013 mb and Standard T=298.15 K

This data can then be corrected to ambient conditions using the ambient P and T and the following formula:
                        Ambient data = STP data*(Ambient P/Standard P)*(Standard T/Ambient T)
                                                                   with Ambient P and T found in the aircraft data files and merged           
                                                                   data sets                                      

The optical data (absorption and scattering) have not been corrected to STP for historical reasons.  Most 
uses of aerosol optical data (visibility, radiative forcing, and comparison to remotely measured aerosol 
properties for example) have required ambient aerosol optical properties, not STP corrected data.  The 
optical data submitted is not truly at ambient conditions (see (2) above); however, the reported data is very 
nearly so (within 5%).  To retrieve true ambient optical properties, one must first correct to STP and then 
correct to ambient conditions.  If one wishes to use STP optical properties (to compare to various gas phase 
measurements for example), we have included a column in our submitted data that contains a multiplier to 
correct the reported optical properties to STP.      

The liquid water content (LWC) of the air is also not corrected to STP. 

Table 1):

Aerosol measurement:                           STP correction applied:       Submitted data found in:
CN @ 300 C			Yes			tcaerpf##.pmb
CN @ 30 C			Yes			tcaerpf##.pmb
Sub-um scattering @ 3 wavelengths	No			tcaerpf##.pmb
Total scattering @ 3 wavelengths	No			tcaerpf##.pmb
OPC integral number (various cut
 sizes) @ 30 C			Yes			tcopcpf##.pmb
OPC integral volume (various cut
 sizes) @ 30 C			Yes			tcopcpf##.pmb
OPC integral surface area
 (various cut sizes) @ 30 C		Yes			tcopcpf##.pmb
DMA integral number @ 30 C		Yes			tcdmapf##.pmb
DMA integral volume @ 30 C		Yes			tcdmapf##.pmb
DMA integral surface area 
  @ 30 C				Yes			tcdmapf##.pmb
LWC				No			tclwcpf##.pmb
Absorption			No			tcabspf##.pmb

CN = Condensation nuclei concentrations 
DMA = Differential mobility analyzer (size distribution measurement with 0.008<=diameter<=0.28 ?m)
OPC = Optical particle counter (size distribution measurement with 0.28<=diam<=0.6 ?m,            
0.6<=diam<=4.0 ?m, and 0.28<=diam<=4.0 ?m cut sizes)