Guidelines for participating stations

Please read the full document for details

 

Scope of the campaign:

This campaign is organized as part of the ACTRIS initiative for studying the changes in the atmosphere during the COVID-19 lockdown. Two types of data will be issued:

  • Near-real-time data, partially quality-assured – to allow fast analysis of the status of the atmosphere.
  • Re-analysis data, fully quality-assured – to identify possible changes compared to similar periods in previous years.

 

Participants:

All lidar stations that are able to operate during the lockdown are invited to participate in the campaign. In order to register to the campaign, please send a message to Doina Nicolae and Lucia Mona by 30 April 2020.

The stations should follow the general rules described in the linked document.

 

Contacts:

 

Campaign period:

  • Preparation: 26-30 April 2020

    • Preparation and check-up of the instrument
    • SCC configurations decided and reported
    • QA tests performed and submitted
    • (Test) measurements submitted to SCC

  • Pre-campaign: 1-7 May 2020

    • Measurements submitted to SCC
    • Adjustments of the SCC configurations (if necessary)

  • Campaign: 8-31 May 2020

    • Regular submission of measurements to SCC, fixed configuration

 

Measurement schedule:

Lidar stations should perform measurements each day, as often as possible. At minimum, the following time intervals must be covered:

  • 2h continuous measurements at noon, after the full development of the PBL
  • 2h continuous measurements at nighttime conditions, allowing good Raman measurements

 

Measurement setup:

The instrument should be checked for alignment, stability and noise before the experiment. The settings should remain unchanged during the campaign, to allow the use of the same SCC configurations.

If possible, a full set of QA tests (telecover, Rayleigh-fit + dark-measurement, polarization calibration) should be performed during the preparation period (26-30 April). The QA tests will be used by CARS to check the status of the instrument (full overlap, dynamic range, polarisation calibration factor).

 

Data processing:

For the purpose of this experiment, the use of the SCC is mandatory. Only data processed by the SCC will be used in this study.

Lidar data should be pushed to the SCC in max. 12 h after the end of each measurement. Datasets should be submitted in packages of 2h profiles.

Each station should use max. 2 configurations (daytime and nighttime) to not be changed during the campaign. For lidars with polarization capabilities also a depolarization configuration should be used.

 

Data products’ availability:

Lidar quicklooks will be available at: https://quicklooks.earlinet.org/. Aerosol optical products will be made available in NRT through the THREDDS server:

  • Particle elastic backscatter profiles (daytime measurements)
  • Raman backscatter and extinction profiles (nighttime measurements).
  • Particle/volume depolarization ratio profiles (if applicable).