DELIVERABLE 2 SPECIALIZED NOVEL SOFTWARE FOR THE ACQUISITION AND ANALYSIS OF 6 DIFFERENT LIDAR SIGNALS IN REAL TIME

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1 DELIVERABLE 2 SPECIALIZED NOVEL SOFTWARE FOR THE ACQUISITION AND ANALYSIS OF 6 DIFFERENT LIDAR SIGNALS IN REAL TIME Project Title : Development of a 6-wavelength LIDAR system for the retrieval of the microphysical and chemical aerosol particle parameters in the troposphere: Application in the calibration of the satelliteborne CALIPSO LIDAR system Project code : 05-NON-EU-95 [ΟΠΣ: 27δ] Affiliated Institution : NATIONAL TECHNICAL UNIVERSITY OF ATHENS PHYSICS DEPARTMENT LASER REMOTE SENSING LABORATORY» Project Leader : Dr. Alexandros PAPAYANNIS Assistant Professor Action : Scientific & Technological Cooperation between Greece and Non-EU countries Research Field : Environmental and Space Technologies GSRT Directorate : International S & T Cooperation Directorate Bilateral Relations Division GSRT Officer : V. KERASSIOTI

2 DELIVERABLE 2: Specialized novel software for the acquisition and analysis of 6 different lidar signals in real time Coordinator: NTUA, Partners: NTUA (40%), Raymetrics SA (60%) Abstract A specialized software code has been developed for the acquisition and analysis of 6 different lidar signals in real time. This code is based on the LabView 6.1 software code using the appropriate Graphical Unit Interface (GUI) modules. The code is able to handle, in real time, 6 different lidar signals and to perform analog and photon counting detection. Several user-friendly interfaces are available, showing the temporal evolution of various aerosol optical parameters (extinction and backscatter coefficients, refractive index, single scattering albedo, volume concentration). This deliverable has been prepared by Raymetrics SA using the relative experience of the NTUA lidar team in the design and development of similar software packages. DELIVERABLE 2: Specialized novel software for the acquisition and analysis of 6 different lidar signals in real time During the 2 nd phase (Phase II) of the project, a specialized software code has been developed for the acquisition and analysis of 6 different lidar signals in real time (355, 387, 407, 532, 607 and 1064 nm). The code is based on the LabView 6.1 software code using the appropriate Graphical Unit Interface (GUI) modules. The code is able to handle, in real time, 6 different lidar signals and to perform analog and photon counting detection. The software code handles both the acquisition of up to 6 lidar signals and the analysis (in real time) of the acquired digitized signals. 1) Software code for the acquisition of up to 6 lidar signals This software code is able to handle simultaneously up to 6 different lidar signal acquired in both analog and photon counting modes. The code initially starts with a screen (Fig. 1) where the option of the Alignment (Coarse or Fine) of the laser beam or the Data Acquisition is required from the user. 2

3 Figure 1. The first window (option) of the Acquisition Software. Once the Data Acquisition option is chosen the next window appears (Fig. 2), where the user selects the desired wavelength to visualize. In the current snap-shot the wavelength 532 nm Analogue Mode is chosen (red circle). Figure 2. The Data Acquisition window of the Acquisition Software. Then, the user pushes the Start button and the acquisition in all 6 wavelengths starts, automatically. Once the acquisition of the lidar signals is complete, the user switches to the Analysis software code, which is presented in detail in the following paragraph. 3

4 2) Analysis software of the acquired digitized lidar signals This software initially starts with the presentation of the currently available lidar signals data-sets (organized in a database) to be processed. When the Preview button (upper left) is active (green button) all the available lidar data are presented in a form of a database. In the example shown (Fig. 3) the lidar signal acquired at 532 nm (photon counting) is shown from 0 up to 10 km height. In this way all the available lidar signals are visualized so that the user can select those in which is interested. In addition, the number of files (per day) and the acquisition time (start end) at all six wavelengths is presented. Figure 3. A typical example of lidar signal acquired at 532 nm (photon counting) on 25/01/2007. The next step of the Analysis software is the processing of each lidar signal separately (The Worksheet button is now acrtive). For instance, in Fig. 4 (upper part) we present the acquired signal processed (e.g. the digitally filtered logarithm of the range- and background-corrected lidar signal) at 355 nm and the corresponding one at 387 nm (Raman- 4

5 shifted by the atmospheric N 2 ) in Fig. 4 (lower part). We see that the 355 nm signal has a high signal-to-noise ratio (SNR) up to km height, while the one at 387 nm reaches lower altitudes (typically up to 6-8 km height). Figure 4. Typical example of the digitally filtered logarithm of the range- and backgroundcorrected lidar signals at 355 nm (upper graph) and 387 nm (lower graph). The next step involves the final processing of the various lidar signals and the retrieval of the aerosol optical properties (aerosol extinction and backscatter coefficients, lidar ratio, etc.). After application of various digital filters and use of the Raman and Klett retrieval algorithms, the above mentioned aerosol optical properties can be finally retrieved. 5

6 A typical example of the retrieval of the aerosol backscatter coefficient - versus altitude at 355 nm using the Raman algorithm is presented in Fig. 5. Figure 5. Typical example of the retrieval of the aerosol backscatter coefficient - versus altitude at 355 nm using the Raman algorithm. Therefore, the software code developed is able to handle up to 6 different lidar signals and to retrieve the various aerosol optical properties (aerosol extinction and backscatter coefficients, lidar ratio, etc.) in real time. Conclusions-Next steps According to the work described before, the Deliverable (D.2) has been fully accomplished, regarding the acquisition and analysis software code of the 6-wavelength NTUA Raman-lidar system in real time for the retrieval of the various aerosol optical properties. In addition, during Phase II, the aerosol post-analysis software code has started to be modified by Georgia Institute of Technology (GIT), for the retrieval of the aerosol chemical composition in relation to the water mass content using as input real lidar data, using the ISORROPIA II code. Currently, this code is tested with lidar inverted data at 355, 532 and 1064 nm, along with water vapor data (at 407 nm) and thus, the Deliverable (D.3) is in good 6

7 progress. Therefore, the project is performing very well, and always in accordance with the scheduled time-table. I certify that the above-described work has been correctly accomplished. The Project Leader Date: 15/02/2007 Dr. Alex. PAPAYANNIS Assistant Professor at NTUA 7