Kipp&Zonen BSRN Scientific Solar Monitoring System User Manual
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Devices that use diffusers should also be cleaned daily by gently brushing debris from the diffuser
m aterial. If the diffuser is extrem ely dirty, distilled water can be used on m ost diffusers, but other cleaning
chem icals should be avoided. The m anufacturer should be consulted on the m ost appropriate cleaning
m ethods.
The half-angle of spectral radiom eters is generally less than half that of pyrheliom eters. Therefore,
pointing alignm ent of these instrum ents m ust be checked regularly; even if active-tracking is being
used. Any changes in the alignm ent of the optical axes of either the radiom eter or the active-tracking
sensor can lead to large errors in AOD. Som e active-trackers allow for the m onitoring of the output
of the active sensor, while a few spectral radiom eters have quadrant sensors im bedded in the instrum ent
that logs the pointing accuracy. Both of these devices can be used to m onitor the quality of the pointing.
On system s that com bine active-tracking with passive tracking, the system clock should be checked
regularly so that the passive m ode points correctly also.
7.6
Archive Information
Data transm itted to the archive will be in the form of spectral transm ission at the wavelengths given
in Table 7.1. To calculate AOD from the transm ission data, the archive will require inform ation on both
the instrum ent and the atm osphere at the tim e of the observation. Table 7.2 sum m arizes the data required
by the archive to calculate the AOD from the transmission value, while Table 7.3 outlines the instrum ent
param eters required to understand the m easurem ent.
Parameter
Description
Comment
Date
Date of observation
Date in archive form at
Tim e (t)
Tim e of m easurem ent
in seconds of the day
Num eric value from 1 to 86400
Delta Tim e (*t)
Period in seconds to
collect observation set
To be used in calculations and quality assurance of
tim e
Observed Solar
t
Zenith (2 )
Observed solar zenith
angle in radians
To be used in calculations and quality assurance of
tim e
P(t)
Actual atm ospheric
pressure (hPa) at tim e
of observation
To be used in calculations. May be subm itted
separately with other archived data
3
O
Colum n ozone am ount
in atm . cm
To be used in calculations. May be subm itted
separately with other archived data. Ozone am ount
is to be representative of ozone overburden at
tim e t
Radiom eter
Tem perature
Num eric in °C
Instrum ent tem perature if therm ostatically controlled
or available if not controlled. The am bient
tem perature is sufficient for instrum ents without
tem perature control. The latter m ay be subm itted
separately with other archived data
1
Transm ission at 8
8
1
(T )
Direct transm ission
Diffuse transm ission
1
8
1
at 8 (D )
Diffuse transm ission
For cosine style instrum ents only
1
n
Repeat Transmission parameters for each measured w avelength (8 ... 8 )
Table 7.2. Inform ation that is required by the archive to calculate AOD from transm ission data.