Kippzonen BSRN Scientific Solar Monitoring System Uživatelský manuál stáhnout pdf (Strana 59)

6.0 Maintenance

6.1 Introduction

High quality, consistent on-site maintenance is crucial if accurate long-term records are to be obtained.

Not only does the individual have to care for the instruments, they must also carefully document any

work that they do on those instruments. It is not good enough to assume that instruments are cleaned

regularly; this activity must be properly documented. To help in this documentation, sample log sheets

are reproduced in Annex G. Many national networks have developed their own methods of documentation

and these can be used if they contain the appropriate information for the radiometers. ALL MAINTENANCE

PROCEDURES, VARIATIONS IN INSTRUMENT BEHAVIOUR AND CHANGES IN INSTRUMENTATION

MUST BE FULLY DOCUMENTED WITH RESPECT TO ACTIVITY, TIME AND DATE.

6.2 Daily Maintenance

The minimum daily requirements for maintaining a BSRN radiation station are as follows:

(1) Cleaning:

(i) Active Cavity Radiometers: Radiometers fitted with a protective optical flat should be

cleaned using a soft cloth and/or a photographer’s airbrush. Material adhering to the

surface of the optical window should be removed using a soft cloth dampened by either

deionized water or methyl hydrate (or equivalent). If the window is other than glass

or quartz, the type of solvent used for cleaning the material must be checked before

applying it to the surface. Care should be taken to ensure that no build-up of material

is found at the border of the flat with the flange holding it on the instrument. When cleaning

with any type of liquid, it is essential that no film or residue be left on the surface. The

general procedures outlined below should be followed if frost or ice is on the window.

For cavity radiometers without protective flats the area around the opening aperture

should be inspected and any foreign material should be brushed away from the opening.

(ii) Pyranometers and Pyrheliometers: The exterior of domes or optical surfaces of each

instrument must be cleaned at least once per day. It is preferable that this cleaning

is done before dawn. However, if this cannot be accomplished, the sensors should

then be cleaned as early as possible during the day. If possible, the instruments should

also be cleaned following the occurrence of any form of precipitation or atmospheric

events that would cause degradation to the signal. Each time an instrument is cleaned,

the time and duration of the cleaning should be recorded in the site documentation.

All loose dust or particulate matter should be blown off gently (a camera brush is a

useful tool) before the dome is wiped. Using a soft lint-free cloth the dome should then

be wiped clean. If any matter is adhering to the dom e, either deionized water or methyl

hydrate (or equivalent) should be used to wet the cloth before cleaning the dome. Do

not pour the liquid onto the dom e directly. Caution must be used so that the dom e is

not scratched, nor the instrument moved, during this procedure. Any film left from the

cleaning material must to removed.

Several methods may be used to remove frost or ice from the dome, depending upon

the severity. Light deposits can be removed by lightly rubbing the surface using the

lint-free cloth as in norm al cleaning. Heavier deposits can be removed by using a methyl

hydrate solution on the cloth. Where an ice build-up cannot be removed with methyl

hydrate alone, the observer (depending on weather conditions) can melt the ice by

placing his hand on the dome. In severe cases a hand-held hair dryer can be used.

In the most severe cases the instrument should be removed and brought inside to thaw.

Using any sharp objects to chisel away the ice is NEVER appropriate. In cases where

the ice is melted by whatever means, the dome should be cleaned with methyl hydrate

and then wiped with a clean lint-free cloth following the operation. The procedure used

and the time required should be documented.

While cleaning the dome, an inspection should be made to decide whether any scratches

or chips have occurred since the last cleaning. Such marks are made by scouring of

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