Università degli Studi di Napoli Federico II DOTTORATO DI RICERCA IN FISICA Ciclo 30° Coordinatore: Prof. Salvatore Capozziello Settore Scientifico Disciplinare FIS/05 Characterisation of dust events on Earth and Mars the ExoMars/DREAMS experiment and the field campaigns in the Sahara desert Dottorando Tutore Gabriele Franzese dr. Francesca Esposito Anni 2014/2018 A birbetta e giggione che sono andati troppo veloci e a patata che invece adesso va piano piano Summary Introduction ......................................................................................................................... 6 Chapter 1 Atmospheric dust on Earth and Mars............................................................ 9 1.1 Mineral Dust ....................................................................................................... 9 1.1.1 Impact on the Terrestrial land-atmosphere-ocean system .......................... 10 1.1.1.1 Direct effect ......................................................................................... 10 1.1.1.2 Semi-direct and indirect effects on the cloud physics ......................... 10 1.1.1.3 Indirect effects on the biogeochemical system .................................... 11 1.1.1.4 Estimation of the total effect ............................................................... 11 1.2 Mars .................................................................................................................. 12 1.2.1 Impact on the Martian land-atmosphere system ......................................... 13 1.3 Dust lifting phenomena ..................................................................................... 14 1.3.1 Dust Storms ................................................................................................. 14 1.3.1.1 Martian Dust storm .............................................................................. 14 1.3.2 Dust Devils.................................................................................................. 15 1.3.2.1 Dust Devils on Mars ............................................................................ 18 1.4 Physics of the boundary layer ........................................................................... 19 1.4.1 Atmospheric Stability ................................................................................. 20 1.4.2 Neutral case ................................................................................................. 21 1.4.2.1 Wind Speed Profile .............................................................................. 21 1.4.2.2 Temperature Profile ............................................................................. 22 1.4.3 Not neutral case........................................................................................... 23 1.4.3.1 Stability parameters L, Ri, Rb .............................................................. 23 1.4.3.2 Wind Speed Profile .............................................................................. 24 1.4.3.3 Temperature Profile ............................................................................. 24 1.4.4 Dust feedback.............................................................................................. 25 1.5 Physic of dust lifting ......................................................................................... 25 1.5.1 Suspension .................................................................................................. 25 1.5.2 Saltation ...................................................................................................... 26 2 1.6 Electrification .................................................................................................... 29 1.6.1 Electrification on Mars ............................................................................... 30 Chapter 2 The ExoMars missions and the Moroccan field campaigns: detection and study of dust lifting events ................................................................................................ 31 2.1 The ExoMars program ...................................................................................... 31 2.2 The DREAMS Experiment ............................................................................... 33 2.2.1 MicroARES................................................................................................. 34 2.2.2 MicroMED .................................................................................................. 35 2.3 Saharan field campaigns ................................................................................... 37 2.3.1 2013 field campaign .................................................................................... 38 2.3.2 2014 field campaign .................................................................................... 39 2.3.3 2017 field campaign .................................................................................... 41 2.4 DREAMS as dust devils probe on Mars ........................................................... 42 2.5 Dust storm detection ......................................................................................... 44 2.6 Dust Devil detection ......................................................................................... 45 2.6.1 Time domain research ................................................................................. 46 2.6.1.1 Pre-processing of the data .................................................................... 46 2.6.1.2 2013 detection algorithm ..................................................................... 47 2.6.1.3 2014 Detection algorithm .................................................................... 49 2.6.2 Tomography technique ............................................................................... 50 2.6.2.1 Application to dust devils and categorization of the detections .......... 52 2.6.3 Validation of Tomography technique ......................................................... 56 2.6.3.1 Comparison of the different methods .................................................. 58 2.7 Dust Devil impact parameter ............................................................................ 60 Chapter 3 Proprieties of the dust induced E-field ....................................................... 64 3.1 Dust Storms ....................................................................................................... 64 3.1.1 Bimodality of the observed dust storm distribution .................................... 65 3.1.2 E-field proprieties ....................................................................................... 69 3.1.2.1 Relation with the dust concentration and atmospheric relative humidity 70 3 3.1.2.2 E-field feedback on dust emission ....................................................... 72 3.2 Dust Devils........................................................................................................ 75 3.2.1 Daily and seasonal activity ......................................................................... 76 3.2.2 Wind speed regime ..................................................................................... 78 3.2.3 Pressure drops distribution .......................................................................... 80 3.2.4 E-field proprieties ....................................................................................... 81 3.2.4.1 Distribution and Orientation ................................................................ 81 3.2.4.2 Signal trend and connections to the other vortex parameters .............. 83 3.2.4.2.1 E-field vs vortex pressure drop and wind speed ............................. 86 3.2.4.2.2 E-field vs vertical flow speed .......................................................... 87 3.2.4.2.3 E-field vs lifted dust ........................................................................ 88 3.2.4.3 Sources of uncertain ............................................................................ 89 3.2.5 Parallel to the martian case ......................................................................... 90 Chapter 4 Evaluation of the intrinsic vortex parameters ............................................. 94 4.1 2017 field campaign .......................................................................................... 94 4.2 Impact parameter evaluation model .................................................................. 97 4.2.1 Concordant Rotation ................................................................................. 100 4.2.1.1 Not-direct passage ............................................................................. 100 4.2.1.2 Direct passage .................................................................................... 102 4.2.2 Discordant Rotation .................................................................................. 104 4.2.2.1 Not-direct passage ............................................................................. 104 4.2.2.2 Direct passage .................................................................................... 105 4.2.3 Reconstruction of the vortex intrinsic parameters .................................... 107 4.2.4 Application of the model .......................................................................... 107 4.3 Camera images distances evaluation .............................................................. 108 4.3.1 Evaluation of the starting values ............................................................... 111 4.3.2 Fitting