Radiatively-driven processes in forest fire and desert dust plumes [Elektronische Ressource] / vorgelegt von Bernadett Barbara Weinzierl

Bernadett Barbara Weinzierl

Informations

• Publié par: ludwig-maximilians-universitat_munchen
• Publié le: 01 janvier 2007
• Nombre de lectures: 20
• Poids de l'ouvrage: 3 Mo

Extrait

Radiatively-driven processes in
forest fire and desert dust plumes


Bernadett Barbara Weinzierl



















München 2007








Radiatively-driven processes in
forest fire and desert dust plumes


Bernadett Barbara Weinzierl











Dissertation
an der Fakultät für Physik
der Ludwig-Maximilians-Universität
München



vorgelegt von
Bernadett Barbara Weinzierl
aus Rosenheim





München, 9. November 2007













































Erstgutachter: Priv. Doz. Dr. Andreas Petzold
Zweitgutachter: Prof. Dr. Olaf Krüger
Tag der mündlichen Prüfung: 10. Januar 2008

Contents
ABSTRACT ............................................................................................................... III
ZUSAMMENFASSUNG.............................................................................................. V
1 INTRODUCTION................................................................................................. 1
1.1 The aerosol in the global climate system............................................................................... 1
1.2 Biomass burning and desert dust aerosol in the atmosphere.................................................. 5
1.2.1 Biomass burning aerosol ................................................................................................... 5
1.2.2 Desert dust aerosol............................................................................................................. 7
1.2.3 Long-range transport of biomass burning and desert dust aerosol .................................. 10
1.3 Objectives of this thesis ....................................................................................................... 11
1.4 Structure............................................................................................................................... 14
1.5 Use of external data and software routines .......................................................................... 14
2 AEROSOL FUNDAMENTALS........................................................................... 17
2.1 Aerosol in the atmosphere – sources, sinks and life cycle................................................... 17
2.2 Microphysical properties of aerosol particles ...................................................................... 19
2.2.1 Aerosol size distribution.................................................................................................. 19
2.2.2 Aerosol mixing state........................................................................................................ 22
2.3 Optical properties of aerosol particles ................................................................................. 23
2.3.1 Definition of key quantities ............................................................................................. 23
2.3.2 Scattering and absorption by particles............................................................................. 26
3 METHODS 31
3.1 Aerosol measurements aboard the Falcon research aircraft................................................. 31
3.1.1 The DLR research aircraft Falcon 20-E5......................................................................... 31
3.1.2 Condensation Particle Counter (CPC) 32
3.1.3 Diffusion Screen separators (DS) .................................................................................... 35
3.1.4 Differential Mobility Analyser (DMA) ........................................................................... 37
3.1.5 Optical particle counters (OPC) ...................................................................................... 38
3.1.6 Particle Soot Absorption Photometer (PSAP) ................................................................. 42
3.1.7 Thermal Denuder (TD).................................................................................................... 44
3.1.8 The Falcon aerosol inlet .................................................................................................. 44
3.1.9 Data quality assurance..................................................................................................... 46
3.2 Field experiments................................................................................................................. 54

i CONTENTS
3.2.1 Measurement concept for airborne studies of aerosol properties .................................... 54
3.2.2 The ITOP study – Forest fire aerosol .............................................................................. 56
3.2.3 The SAMUM study – Desert dust aerosol....................................................................... 62
3.2.4 Differences between ITOP and SAMUM........................................................................ 66
3.3 Data analysis ........................................................................................................................ 67
3.3.1 Volumetric units and aerosol modes................................................................................ 67
3.3.2 Time series of microphysical aerosol properties and data reduction............................... 68
3.3.3 Size distribution data ....................................................................................................... 68
3.3.4 Validation of the inversion algorithm 74
3.3.5 Volatility analyses – aerosol mixing state 75
3.3.6 Absorption data................................................................................................................ 77
3.3.7 Aerosol optical model...................................................................................................... 78
3.3.8 Heating rates.. 79
3.3.9 Combination of data ........................................................................................................ 79
4 PROPERTIES OF FOREST FIRE AND DESERT DUST PLUMES .................. 83
4.1 Forest fire aerosol (ITOP).................................................................................................... 83
4.1.1 Transport of forest fire plumes to Europe........................................................................ 83
4.1.2 Case study 22 July 2004 .................................................................................................. 84
4.1.3 Optical properties of the aged forest fire plume on 22 July 2004.................................... 88
4.1.4 Properties of other forest fire plumes during ITOP ......................................................... 91
4.2 Desert dust aerosol (SAMUM) ............................................................................................ 93
4.2.1 Properties of dust aerosol layers south of the Atlas Mountains....................................... 93
4.2.2 Desert dust layers at the boundary between source and long-range transport regime... 105
4.2.3 Properties of aged dust layers........................................................................................ 112
4.2.4 Optical properties of dust layers.................................................................................... 114
5 DISCUSSION AND CONCLUSIONS .............................................................. 119
5.1 Hypothesis I – Self-stabilising effect................................................................................. 120
5.1.1 Heating rates.................................................................................................................. 120
5.1.2 Static stability ................................................................................................................ 126
5.1.3 Wave breaking and mixing............................................................................................ 130
5.2 Hypothesis II – Sealed ageing effect.................................................................................. 132
5.2.1 Nucleation and Aitken mode ......................................................................................... 132
5.2.2 Accumulation mode....................................................................................................... 135
6 SUMMARY AND OUTLOOK........................................................................... 137
6.1 Summary of results ............................................................................................................ 137
6.2 Open scientific questions ................................................................................................... 141
ACKNOWLEDGEMENTS....................................................................................... 145
LIST OF ABBREVIATIONS .................................................................................... 147
LIST OF SYMBOLS...............................................................