8 2 Global distributions, time series and error characterization of atmospheric ammonia (NH3) from IASI satellite observations 9 2.1 Introduction

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Contents

List of acronyms III

1 General introduction 1

1.1 Background . . . . 2

1.1.1 Reactive nitrogen in the environment . . . . 2

1.1.2 NH3in the atmosphere . . . . 4

1.1.3 Satellite remote sensing of NH3 . . . . 6

1.2 Aim and outline . . . . 7

1.3 Data availability . . . . 8

2 Global distributions, time series and error characterization of atmospheric ammonia (NH₃) from IASI satellite observations 9 2.1 Introduction . . . . 10

2.2 The Infrared Atmospheric Sounding Interferometer (IASI) . . . . 11

2.3 Retrievals of NH₃from IASI . . . . 12

2.3.1 Overview of retrieval schemes and spectral ranges . . . . 12

2.3.2 A retrieval scheme based on the calculations of hyperspectral range index . . . . 13

2.3.2.1 Hyperspectral Range Index (HRI) . . . . 13

2.3.2.2 Look-up tables . . . . 14

2.3.2.3 Global processing of IASI data . . . . 17

2.4 Results and discussion . . . . 18

2.4.1 Product evaluation . . . . 18

2.4.2 Global and regional distributions . . . . 20

2.4.3 Temporal evolution . . . . 25

2.5 Conclusions and perspectives . . . . 26

3 Evaluating four years of atmospheric ammonia (NH₃) over Europe using IASI satellite observations and LOTOS-EUROS model results 29 3.1 Introduction . . . . 30

3.2 Method . . . . 31

3.2.1 NH3from IASI . . . . 31

3.2.2 LOTOS-EUROS model . . . . 32

3.2.3 Regularizing IASI and LOTOS-EUROS columns . . . . 33

3.3 Results . . . . 34

3.3.1 Four-year mean . . . . 34

3.3.2 Inter-annual analysis . . . . 35

3.3.3 Intra-annual variability . . . . 38

3.3.4 Russian fire episode in 2010 . . . . 42

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3.4 Conclusions and perspectives . . . . 44

4 Towards validation of ammonia (NH3) measurements from the IASI satellite 47 4.1 Introduction . . . . 48

4.2 Measurement data sets . . . . 49

4.2.1 Satellite observations . . . . 49

4.2.2 Ground-based observations . . . . 50

4.2.3 Airborne observations . . . . 51

4.3 Results and discussions . . . . 52

4.3.1 Comparison with ground-based observations . . . . 52

4.3.1.1 Global evaluation . . . . 52

4.3.1.2 Regional focus . . . . 54

4.3.2 Comparison with airborne observations . . . . 59

4.4 Conclusions and perspectives for the validation . . . . 61

5 Worldwide spatiotemporal atmospheric ammonia (NH3) variability revealed by satellite 63 5.1 Introduction . . . . 64

5.2 IASI-NH3observations . . . . 65

5.3 Spatio-temporal variability . . . . 65

5.3.1 Yearly distributions . . . . 65

5.3.2 Seasonality and monthly variability . . . . 65

5.3.3 From total columns to main source processes . . . . 69

5.4 Conclusions . . . . 70

6 Synthesis 73 6.1 Conclusions and perspectives . . . . 74

6.1.1 Principal achievements and limitations . . . . 74

6.1.2 Ongoing activities . . . . 75

6.2 Outlook . . . . 77

7 Summaries 79 7.1 Summary . . . . 79

7.2 Samenvatting . . . . 81

7.3 R´esum´e . . . . 83

Bibliography 85

Appendix A 103

Appendix B 107

Appendix C 111

Peer-reviewed publications 113

Acknowledgements 115

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