On March 24, 2021 it was organized a group meeting as a telecon. This was aimed at discussing the level of implementation for the stage 4 activities of component project 1 - CONTUR. The meeting was attended by Professor Emeritus Sabina Stefan (University of Bucharest - partner institution P5), Professor Marius Stoia (University Politehnica of Bucharest - partner institution P1), Dr. Livio Belegante and PhD student Razvan Pirloaga (INOE 2000 - partner institution P2), Assistant Professor PhD Nicolae Ajtai and Dr. Horatiu Stefanie (The Babes - Bolyai University of Cluj - Napoca - partner institution P4) and Dr. Aurelian Andrei Radu (Institute of Space Science - the coordinating institution of the CONTUR project CO).

The telecon agenda included the following items:

• opening remarks and management elements for the CONTUR project (Dr. Aurelian Andrei Radu)


• a presentation of the current status of implementation for the stage 4 technic and scientific activities of the component project 1 - CONTUR (PhD student Razvan Pirloaga)


• recommendations to optimize the implementation of the CONTUR project timeline activities (contributions from all attendees).

In the early days of August 2020, Mr. Livio Belegante (INOE 2000 - P2) was on a professional visit to The Babes-Bolyai University of Cluj - Napoca - P4. The purpose of this visit was to prepare the test, measurement and data acquisition campaign - CONTUR 3. During this visit, on August 6, 2020, a telecon was organised. The attendees were: Mr. Livio Belegante and Mr. Horatiu Stefanie (The Babes - Bolyai University of Cluj - Napoca - P4) from Cluj-Napoca, and from Bucharest, Prof. Sabina Stefan (The University of Bucharest - P5), Mr. Razvan Pirloaga (INOE 2000 - P2) and Mr. Aurelian Andrei Radu (Institute of Space Science - CO).

The telecon agenda included the following items:

• opening remarks (Mr. Livio Belegante)
• an update on the status of the Bucharest LIDAR systems (Mr. Livio Belegante)


• an update on the status of the Cluj-Napoca LIDAR systems (Mr. Horatiu Stefanie)


• a general exposition of the CONTUR 3 campaign: plans for two locations - Bucharest and Cluj - Napoca, devices to be used, data analysis (Mr. Livio Belegante)


• the wind LIDAR and the SODAR system - new equipment to be used for the CONTUR project (Mr. Razvan Pirloaga)


• the assessment of the implementation of stage 3 activities in compliance with Annex II.b of contract 87PCCDI / 2018 (Dl. Aurelian Andrei Radu).

Herein it was underlined the importance of dissemination of the obtained results and it was also put forward that the CONTUR workshop take place as a section of the international conference AEROSPATIAL 2020.

On 20.09.2019, a work meeting took place at ISS headquarters, dedicated to the project component P1-CONTUR. The meeting's agenda included the following points:
1. information regarding the testing campaigns of INOE's LIDAR systems for detecting turbulence phenomena at different altitude levels;
2. Information regarding an oral presentation (Phys. Dr. Aurelian Andrei Radu) and a poster type presentation (Dr. Prof. Sabina Stefan) at the European Meteorological Society International Conference - EMS 2019, which took place at Copenhaga, Denmark during September 7 - 11, 2019;
3. the accomplishment degree of the activities related to stage 2 (December 2019) implemented to the project component P1, of the complex project CONTUR;
4. Evaluation of the development process of the planned deliverables;
5. Optimization of the utilized human resource for each separate activity.

During the period of September 9 - 13, 2019, Univ. Prof. Dr. Sabina Stefan and Phys. Dr. Aurelian Andrei Radu participated at the EMS Annual Meeting: European Conference for Applied Meteorology and Climatology 2019 that took place at the The Technical University of Denmark (DTU) in Lyngby, Danemarca.

Phys. Dr. Aurelian Andrei Radu gave an oral presentation with the title: "Study of Clear Air Turbulence in Romanian Airspace" and Univ. Prof. Dr. Sabina Stefan gave a poster type presentation with the title: "Study of Clear Air Turbulence Related to Tropopause Folding over Romanian Airspace".

A period of intense measurements of the CAT detection performances of LIDAR technologies (CONTUR 2) was carried out during a testing campaign from June 10 to June 14, 2019. Knowing that forecasting the CAT phenomenon is difficult and the uncertainties associated with it are large, this campaign was aimed at the detection of turbulent events using direct detection methods: LIDAR. For this reason, the campaign focused on the detection of turbulent phenomena caused by different sources: the passage of large size airplanes (wake turbulence), turbulent events in clear sky at high altitudes (CAT) highlighted by consulting specific forecast models, turbulent events in the Planet Boundary Layer (PBL) caused by the exchange of thermal energy between the ground and the air. The CONTUR 2 campaign mostly used the last type of events due to the low altitudes at which they are formed: 1-4 km.

Since the measuring of molecular depolarization for predicting turbulent phenomena requires a high stability on the optical alignment and a preliminary instrument calibration, the campaign ensured a preparation phase. This phase included the optimization of the signal so that the signal to noise ratio was improved for collecting the data at reduced integration time. A second phase for preparing the instruments consisted of calibrating the depolarization LIDAR channel. The LIDAR system used during this campaign was equipped with calibration modules for the depolarization channels able to eliminate the systematic errors produced by the measuring instruments (Belegante et. Al., 2018).

The testing of the performances of the LIDAR systems was done by analysing the measured profiles for low integration periods (10-30 seconds) - 2019.06.13. The figures below present the profiles of the volume depolarization for two multichannel Raman LIDAR systems, with measurements done in VIS (532 nm).
In the case of this analysis, the statistical errors associated with the profiles were considered the primary indicator for determining the quality of the signal. Keeping in mind the fact that molecular depolarization in the case of the measured profiles in VIS is of order 0.005, the LIDAR signal can be considered useful for statistical errors that would be better or at least comparable with this value. For the optimization of the signal, we used profiles obtained at 10, 20 and 30 second intervals - day time and night time measurements.

From the LIDAR signal analysis, it was noticed that the integration time had a somewhat limited effect. This pattern can be explained by the fact that the difference between the three configurations (30, 20, 10 s) was relatively small and the noise associated with the signal had a quadratic dependency. Comparison between the day time and night time measurements showed great improvement. The maximum altitude at which the turbulence studies could be made during the night time reached 3-4 km. This difference was due to the low background noise in the case of the measurements made during the night.
Examples:

The temporal series showed a turbulent atmosphere, especially in the lower altitudes of the PBL (up to 2000 m). The aerosol layer visible at 1500-1700 m indicated the presence of vertical gradients that reached velocities of 2 m/s. The depolarization profile presented a decrease of 0.003 for that altitude.

The temporal series and depolarization profile indicate a similar pattern with that found in the previous case. The aerosol level visible at 1750 m indicates the presence of vertical gradients that reach velocities of 3 m/s. The depolarization profile indicates a decrease of 0.003 for this altitude - the area where the concentration of aerosols remains constant (1650-1800 m).

On Thursday May 3rd, 2018, a kick-off meeting dedicated to the analysis of various aspects concerning the optimum implementation of this component project took place at the headquarters of The National R&D Institute for Optoelectronics - INOE 2000 (the coordinating institution of the component project 1). During this session, it was elaborated an action items plan for the next months. The following items were included: the identification of tropopause folding cases from ozone LIDAR data, the analysis of synoptic situations for the previous cases, the identification of the optimum season and location for the ground data acquisition performed with a LIDAR system, the organization of LIDAR performed measurement campaign and the dissemination of the results on scientific conferences and workshops. A couple of photos from this meeting are included underneath.