CPD2 Records

A CPD2 record is a collection of variables and a timestamp. By definition the combination of a station, time, and variable specifies a globally unique value in the DB system even if the variable appears in multiple records.

Most records are uniformly spaced in time and aligned to time boundaries. That is, one minute data appears every minute on the minute. In most cases the timestamp specifies the start of the period of data that the record presents. For one minute averaged data the timestamp would be the start of the minute that the record represents.

See here for record content definitions. Flags are documented here. Internally data is maintained in the CPD2 data format.

Structure

Most records consist of three parts:

  1. A source instrument type.
  2. An instance number (which may have a sample line encoded in it).
  3. The record type for the combination of the above.

For example, the record S11a consists of the parts:

  1. “S” the source type, Scattering in this case; usually neph data.
  2. “11” the instance number. Here this is encoding that this is the first scattering instrument on the first line. The second instance on the same line (humidified neph, for example) would be “12”.
  3. “a” the record type. This is the “a” record for the “S11” instrument. In most cases that means variables in this record will be named “*_S11”, but that is not required.

This naming is not strictly required by the system. For instance, data.avg can generate records just called “a” when it combines multiple records into a single averaging frame.

By convention all record types end in a lower case letter which is the type of the record. So both “a” and “GPS1a” are valid, but “UPS1” is not. That is, the source specifier is optional (but nearly always included) but the type of the record is not.

Source Types

Some commonly used source types:

  • A - Absorption
  • S - Scattering
  • E - Extinction
  • N - CouNter
  • P - Pressure
  • Q - Flow
  • V - Temperature/RH (Vaisala)
  • F - Filter data
  • G - Gas sampler
  • GPS
  • UPS
  • X - Unclassified or multiple source

Instance Numbering

In normal flow situations there are several standard lines defined (the first of the digits that compose the instance number):

  • Line 0 is the stack and stack sheath flow.
  • Line 1 is the main sample line. Normally the neph(s) and PSAP reside on this line.
  • Line 2 is the chemical filter sample line (if any).
  • Line 6 is used for CN counters with a separate high speed inlet.
  • Line 7 is used for a CN sampling system that draws off the main stack inlet (usually picked off line 1).
  • Line 8 is used to designate any line from a mail inlet other than the main one, but not listed above.

Record Types

Some standard record types (normal instrument type in parenthesis):

Aethalometer (A)
a All parameters at instrument time base.
AIN Simple (X)
a High frequency average of variables being measured by the instrument.
BestUPS (UPS)
a All parameters at high frequency.
CAPS (E)
a High frequency. Extinction, temperature, and pressure.
m Low frequency. Status: flow, voltage and loss.
c Zero results. Baseline
CLAP3W (A)
a High frequency. Absorption, filter information, transmittance and sample length.
m Low frequency. Additional filter information, intensities, flows and temperatures.
n Triggered by spot change. Spot normalization factors.
w Triggered by white filter. White filter parameters.
i Instrument real time (1 second). Instantaneous intensity values.
CCN (N)
a High frequency. Counts, temperatures, flows, pressures, voltages, and supersaturation (reported and calculated)
f CCN vs SS fit results
Various CPCs (N)
a High frequency. Concentration and instrument flags.
m Low frequency. Status: temperatures, flow and pressure.
CR1000/uMAC (X)
a High frequency average of variables being measured by the instrument.
m Low frequency. Temperature and supply voltage.
d Digital state.
Filter (F)
s Statewise. Filter number and all volumes.
Flask (X)
s Statewise. Flask sample information.
GenericPID (X)
m Low frequency. PID integral and residual values.
t Automatic tuning results.
NMEA GPS (GPS)
a High frequency. Fix time, latitude, longitude, altitude, ground speed and course.
GRIMM (N)
a High frequency. Counts and bin sizes.
m Low frequency status information.
Hygrometer (V)
a High frequency. Temperature, RH and dewpoint.
LASAIR (N)
a High frequency. Flow and counts.
m Low frequency. Status.
LovePID/Watlow (X)
a High frequency average of variables being measured by the controllers, possibly also the setpoint values.
TSI Neph (S)
a High frequency. Scattering, backscattering, temperature, RH and pressure.
m Low frequency. Status: voltages and reference.
s Statewise. Flags and status string.
c Zero results. Background
k Spancheck results.
Ecotech Neph (S)
a High frequency. Scattering, backscattering, temperature, RH and pressure.
m Low frequency. Status: Reference.
s Statewise. Flags.
c Zero results. Background
k Spancheck results.
RR Neph (S)
a High frequency. Scattering, temperature, RH and pressure.
m Low frequency. Reference.
k Spancheck results.
Ozone Monitor (G)
a High frequency. Ozone concentration, temperature and pressure.
c Zero results.
k Spancheck results.
PAX (E)
a High frequency. Scattering, absorption and instrument parameters.
c Zero results. Background
PILS (X)
i Statewise. Instrument status.
c Command sent indicator.
PSAP(3) (A)
a High frequency. Absorption, filter information, transmittance and sample length.
m Low frequency. Additional filter information, intensities, flows and temperatures.
PWD22 (X)
p All parameters at instrument time base.
Raw Data (X)
r Raw data record at instrument time base.
SEMS (N)
sz Reported bin sizes at instrument time base.
su Reported up scan counts at instrument time base.
sd Reported down scan counts at instrument time base.
sl Reported dlog(D) at instrument time base.
n Bin counts (dN/dlog(Dp)) calculated from raw data.
d Bin diameters calculated from raw data.
c Scattering and/or absorptions calculated from the n and d records.
SMPS (N)
n Bin counts (dN/dlog(Dp)) calculated from raw data.
d Bin diameters calculated from raw data.
c Scattering and/or absorptions calculated from the n and d records.
Misc. Averaging (X)
a High frequency. Vector average of wind speed and direction.
TDL (G)
a High frequency. Temperature, pressure and water vapor concentration.
TSI MFM (Q)
a High frequency. Temperature, pressure and flow.
VelociCalc (X)
a High frequency. Temperature and flow.
Vertical Profile Control (X)
t Task executed information.

Records not directly generated by a CPD2 physical instrument:

Intensives (XI/XJ)
s Short form, available in one minute and averaged.
l Long form, available in one minute and averaged.
Humidograph (XH)
h Humidograph fits.
CCN Fits (N)
f CCN fits.
wx Best available weather data. Note that this is just a “wx” record with no suffix.
X Message log

Common Examples

Description
S11a Reference neph scattering data.
S12a Humidified neph scattering data.
A11a Absorption.
N61a CN concentration for systems with a high speed inlet.
N71a CN concentration for systems sampling from the main inlet.
XIs Short form intensives record.