סמינר בחוג לגיאופיזיקה: Retrieval of planetary boundary layer height and aerosol vertical profiles employing remote sensing techniques with a focus on ceilometer data
Leenes Uzan, TAU (PhD defense)
The growing importance of the planetary boundary layer (PBL) height detection is apparent in various fields, from air pollution analysis to weather prediction. In recent years micro-lidars such as ceilometers have been recognized as an efficient tool for such research. In this study, we explore the development of the diurnal PBL height in the summer season, measured by a total of eight ceilometers throughout Israel. Although the Israeli summer synoptic conditions are considered quite stable, results for the summer season (July-August 2014) show the inland PBL was about 200 m higher than the onshore site situated only 7.5km apart (Uzan, Egert, Alpert, 2016). Furthermore, we compared the ceilometers' results to the PBL heights derived by weather prediction models, ECMWF-IFS on the global scale and COSMO-IL as the regional model. Results for the Beit Dagan site on August 2015 and 2016 showed good agreement between the models' evaluation and the ceilometer measurements (correlation above 0.7) at 12 UTC. In the flat terrain, both models succeeded to distinguish between different PBL scenarios, even under the same synoptic conditions. COSMO-IL tends to inflate the PBL height, but the height difference is lower than the estimations disclosed by ECMWF-IFS (140 m and 440 m, respectively). Lastly, we utilized the set of ceilometers to investigate the evolution of the extreme dust storm on September 7, 2015, within the first kilometer of the troposphere. The analysis included supplementary data from two spectral radiometers (AERONET), 31 units of ground particulate matter measurements, satellite images, 22 sites of global/diffuse/direct solar radiation measurements' and radiosonde profiles (Uzan, Egert, Alpert, 2018).
Uzan, L., Egert, S. and Alpert, P.: Ceilometer evaluation of the eastern Mediterranean summer boundary layer height–first study of two Israeli sites. Atmos. Meas. Tech., 9(9), 4387-4398, 2016.
Uzan, L., Egert, S., and Alpert, P.: New insights into the vertical structure of the September 2015 dust storm employing eight ceilometers and auxiliary measurements over Israel, Atmos. Chem. Phys., 18, 3203-3221, https://doi.org/10.5194/acp-18-3203-2018, 2018.
מארגן הסמינר: פרופ' איל חפץ