The weather clears (well maybe)...

Michael got back from the lab this morning with news of clear skies. He had a great night of lidar observing from 10:30 PM until 6:30 AM. The winds had died down and there was no cloud. It was the best night of DIAL measurements so far.

When we reached the lab, everyone was looking forward to a good day of measurements. There was a little cloud on the horizon but it didn't look too bad. We planned to do some tests on PARIS after local noon so that we could take all the solar measurements possible. The hopes of the FTS team fizzled as the cloud got thicker and thicker throughout the day. There wasn't enough sunlight by noon to attempt any measurements. Later in the afternoon, Clive and I probed the PARIS metrology detector signals at several optical path difference settings and sent the results off to Bomem so we can try to diagnose the problem.

The SAOZ window was frost free this morning but the instrument temperature was 37 C. Annemarie turned off the heating in the dome hatch and we watched the temperature decrease to about 34 C. We will continue to monitor the temperature and the frost levels over the next days and determine if any changes need to be made in the SAOZ window.

It turns out that the Brewer (on its tracker) is not tall enough for the instrument to see over the railing on the roof to measure the Sun when it is low in the sky. It is not possible to put it up on blocks because the Brewer tracker motion causes the instrument to "walk about" while measuring. Instead, Tom took a hacksaw outside and "customized" the railing by removing the top rung. Now the Brewer can see the Sun (except that it went behind some clouds before Tom could align it completely).

Jennifer and Clive mounted SPS and MAESTRO on the tracker and were ready to start measurements but they needed the Sun to do the final alignment. Right now, the instruments are making zenith sky measurements and waiting for the Sun (like the rest of the team).

The DOAS continued measurements in its roof hatch. Annemarie spent the day doing some data analysis. She started to work on deriving NO2 profiles from her zenith sky measurements.

Paul got to experience the "best part" of the operator's job: hauling effluent from AStrO/PEARL down to the weather station. He also brought a truck load of water up to the lab. Keith continued taking inventory of AStrO/PEARL. We now have lots of pictures of the infrastructure at the lab! You never know when you might need a picture of the AStrO/PEARL water heater or the scaffolding.

Tonight, we started our series of daily ozonesonde launches. The sonde was launched with the synoptic radiosonde at 23:15 UTC. It got to 6.0 mbor which was slightly lower than the most recent radiosondes. Annemarie has "bragging rights" for tomorrow because she came closest with a guess of "2 times pi".

Before we went down to the station for dinner, one of the weather station staff phoned to say that it looked like there was a weather system coming in and we might want to come down to the lab really soon. They were seeing an increase in temperature and decrease in pressure. It was advised that we bring all the items that we may need from the lab (just in case). Maybe, we are seeing the beginning of storm that always seems to happen on Richard M.'s birthday...

Best regards,
Kaley.