Case Study of Coastal Fog Events in Senegal Using LIDAR Ceilometer

作     者：Semou Ndao Cheikh Modou Noreyni Fall Luis Duran Assie Regina Djiguene Diatta Abdou lahat Dieng Badara Sane Amadou Thierno Gaye 

作者机构：Laboratory of Physics of the Atmosphere and Ocean-Siméon Fongang(LPAO-SF)Higher Polytechnic SchoolUniversity Cheikh Anta Diop(UCAD)PO BOX 5085DakarSenegal Department of Earth Physics and AstrophysicsComplutense University of MadridMadrid28040Spain Meteorological Operation ServiceRepresentation of the Agency for the Safety of Air Navigation in Africa and Madagascar(ASECNA)in SenegalPO BOX 3144DakarSenegal Laboratory of Oceanography and ClimateExperiments and Numerical Approaches(LOCEAN)Sorbonne University(SU)Paris75006France 

出 版 物：《Journal of Atmospheric Science Research》 (大气科学研究(英文))

年 卷 期：2023年第6卷第4期

页      面：64-76页

学科分类：07[理学] 0707[理学-海洋科学] 

主　　题：Coastal fog LIDAR Ceilometer Sea level pressure Relative humidity Temperature 

摘      要：This study aims to examine the atmospheric conditions characterising fog phenomena on the Senegalese coast focusing on two specific instances that occurred on April 3 and April 30,*** events were detected by the LIDAR Ceilometer installed at LPAOSF/ESP/UCAD and confirmed on the METARs of the meteorological stations at Dakar and Diass *** LIDAR’s backscatter signal showed that the fog of April 3 started around midnight with a vertical extension at 100 m altitude and dissipated around 10 *** April 30 event characterized by a good vertical extension from the surface up to 300 m above sea level,was triggered just after 2 *** lasted around 3 *** results showed that a decrease in temperature,accompanied by an increase in humidity and light wind,is favorable for the triggering and persistence of *** Level Pressure(SLP)anomaly fields show two distinct *** April 3 event was characterized by a zonal dipole of SLP anomalies between the Sahara and the northern Senegalese coast,while the April 30 event was characterized by a meridional dipole between the Sahara and the Gulf of Guinea area as far as the equatorial Atlantic.A weakening of the pressure around the study area was observed in both cases,allowing moisture advection to favor the onset of *** hovmoller diagrams of relative humidity and wind show that a good vertical extension of humidity associated with a westerly wind in the lower layers plays an important role in the formation and persistence of *** presence of dry air associated with a weak easterly wind in the middle layers could explain the low vertical extension of the fog on April 3.A strong wind in the lower layers would be responsible for the premature dissipation of the April 30 fog.