CAUTION
To be able to prepare an ozone sounding
with MW41, you must import and activate the following scripts:
Import the scripts to the same script group and select OzoneMain.py as the main script. Make sure that script group is set active. You do not need to set a command line argument. For more instructions, see Vaisala Sounding System MW41 Online Help, embedded in MW41 sounding software. |
CAUTION
Do not touch the radiosonde sensors. They are fragile and can be easily contaminated. |
WARNING! During humidity sensor
reconditioning, the temperature of the sensor boom is about 150 °C for 3 minutes. |
- Attach the ozone destruction filter to the pump inlet tube.
-
Place the RS41 radiosonde on the ground check device. The radiosonde is switched on
when you place it on the ground check device. The message Preparation in
progress is displayed in MW41.
CAUTION Do not connect Ozone Interface Board OIF to the radiosonde while the radiosonde is placed on the ground check device. - Before the preparation phase is completed, scroll the MW41 page down to the Special sensor window, and select Ozone from the drop-down list.
-
Fill in the information needed and click Apply.
During this phase, the radiosonde LED light is red, but you can ignore it. It does not indicate an error at this point.
The ASOPOS panel recommends 3.0 cm3 for cathode solution volume. Ozone sensor information During the ground check preparations, the radiosonde status in MW41 may display an error with the message No add-on sensor data (filtered). You can ignore this message and proceed with the preparations, it has no effect on the ozone sounding.
Radiosonde preparation in progress -
When the message Waiting for background current is displayed, remove the
radiosonde from the ground check device.
Waiting for background current -
Connect OIF to the radiosonde using cable CBL210224.
-
Connect the radiosonde cable to the interface terminal
Radiosonde.
Connecting radiosonde cable -
Connect the interface to the radiosonde.
You must break a small piece of the EPS cover to get access to the radiosonde interface. Use your finger, a pen, or a small plastic spoon, as shown in the following figure. Do not use a metallic object.
Slightly bend the piece and remove it.
To avoid short-circuiting the radiosonde, use a non-metallic tool to break the EPS cover. Bending and removing piece of EPS cover -
Before connecting the interface to the radiosonde, check that none of the pins on
the radiosonde interface are deformed
Checking radiosonde interface connector -
Firmly push the connector to the interface connector pins located inside the
radiosonde.
OIF connected to radiosonde interface connector
After the connection, the radiosonde LED light is blinking green. -
Connect the radiosonde cable to the interface terminal
Radiosonde.
-
Attach the radiosonde to the holder in the flight box as instructed below.
Detailed capacity information on the radiosonde battery is available in the radiosonde data sheet. OIF interface reduces the battery operating time by approximately 2–4%. If there are any delays in the sounding preparations or before the sounding starts while the radiosonde is powered from the battery, you can switch off RS41 by pressing the power switch. Switch the radiosonde back on before launching the balloon. -
Hold the radiosonde holder with your other hand and place the radiosonde bottom end
to the holder first.
Attaching radiosonde to the holder -
Use your finger to push the top part of the holder against the radiosonde so that
the radiosonde is tightly attached to the holder.
Pushing the holder into place -
If you attach the radiosonde in a lower position than shown here, push the holder
against the flight box wall.
Radiosonde RS41 attached to the holder
-
Hold the radiosonde holder with your other hand and place the radiosonde bottom end
to the holder first.
-
After attaching the radiosonde, place the ozone sensor into the flight box.
-
For an example of the (SPC) sensor inside the flight box, see the following
figure.
Make sure that the wires and tubes are led through the grooves in the flight box, indicated with the numbers in the figure.
SPC ozone sensor inside the flight box - 1
- Ozone sensor placed inside the flight box
- 2
- Pump motor battery wires led through the groove
- 3
- Air tube led through the groove
-
For an example of the (EN-SCI) sensor inside the flight box, see the following
figure.
Make sure that the wires and tubes are led through the grooves in the flight box.
CAUTION In case of EN-SCI sensor, make sure to place the flight box cover (number 1 in the following figure) and the ozone sensor inside the box (number 2) in the correct position and leave enough headspace for the pump. The cover must not touch the pump as it may prevent the pump from running. Number 3 indicates the radiosonde position on the flight box wall.
EN-SCI ozone sensor inside the flight box, cover about to be closed - 1
- Flight box cover
- 2
- Ozone sensor placed inside the flight box
- 3
- Radiosonde RS41-SG
-
For an example of the (SPC) sensor inside the flight box, see the following
figure.
- Do not connect the battery wire from OIF yet, leave the connectors outside the flight box.
-
Depending on which sensor you use, follow instructions in step a. or b.
-
If you use an (SPC) sensor, close the cover of the flight box and tape the seam
between the cover and the body of the box.
Do not tape the hanging strings.
Do not tape over the air outlet and air intake tube, as the measuring gas must be able to move in and out of the sensor box.
Air outlet hole and air intake tube not taped over - If you use an (EN-SCI) sensor, attach the flight box string with another string in 2 places, indicated with the arrows in the following figure, so that the string does not hit the radiosonde sensor boom during the flight.
Supported flight box string in EN-SCI ozone sensor flight box -
If you use an (SPC) sensor, close the cover of the flight box and tape the seam
between the cover and the body of the box.
-
With ozone destruction filter on or ozone-free air flow connected, run the ozone sensor
for 10 minutes and record the cell current IB2:
Record IB2: ________μA
Background current is measured after the flight box is closed:- Close the cover of the flight box and tape the seam between the cover and the body of the box.
- Do not tape the hanging strings. Do not tape over the air outlet and air intake tube, as the measuring gas must be allowed to move in and out of the sensor box.
See Taped flight box, battery connectors in front and Air outlet hole and air intake tube not taped over.
IB2 has been used for Vaisala IBG = I0, in Vaisala scripts with MW41 sounding software. The latest ASOPOS recommendation in GAW Report 268 is to enter IB0 background current (before exposure to ozone) into the software when background current value is requested. Always record the value indoors with destruction filter or ozone-free air connected, and after inserting the ozone sensor to the flight box.
-
MW41 proposes a background current. Use the value by clicking
Copy.
- You can either use the Copy button or enter the sensor background current in MW41 and click Apply.
Entering sensor background current in MW41 -
In the Monitoring window, go to the Tabular
data tab and select Raw ozone from the drop-down
list. Make sure that ozone data is coming through, showing reasonable ozone current and
ozone flight box temperature.
The following information is displayed:
Viewing raw ozone data in MW41 - Time: time in seconds
- Raw O3: ozone partial pressure
- Current
- Box temperature
- Ozone pump current
- Turn off the pump and either take off the ozone destruction filter or shut off ozone-free air flow.
- Before starting the flight, connect the ozone sensor pump to its power supply as instructed in section Activating Pump Motor Battery.