SCIAMACHY - Exploring the Changing Earth’s Atmosphere (eBook)

Editorial 8
Contents 12
Contributors 14
Chapter 1: SCIAMACHY - The Need for Atmospheric Research from Space 18
1.1How to Study the Earth´s Atmosphere from Space? 19
1.2The Road to SCIAMACHY 20
1.3Determining Impacts on the Earth´s Atmosphere 23
SCIAMACHY´s Goals 23
The Atmospheric Layers 24
Anthropogenic Impact on the Earth-Atmosphere System 26
Tropospheric Chemistry 26
Greenhouse Gases: Global Warming and Climate Change 27
The Tropopause Region 29
Stratospheric Chemistry and Dynamics 29
Mesospheric Chemistry and Dynamics 30
1.4SCIAMACHY´s Past and Beyond Its Future 31
The Initial Phases 31
The Next Decades 32
References 33
Chapter 2: ENVISAT - SCIAMACHY´s Host 35
2.1ENVISAT Attitude and Orbit 36
2.2ENVISAT On-board Resources 39
2.3ENVISAT Ground Segment 40
2.4ENVISAT Data Products 40
2.5Data Access 43
References 44
Chapter 3: The Instrument 45
3.1Instrument Concept 46
3.2Optical Assembly 48
Scan Mechanisms and Baffles 48
Telescope and Spectrometer 51
Detector Modules 51
Calibration Unit 55
Polarisation Measurement Device 55
Radiator A and Active Thermal Control 56
Thermal Bus 57
3.3Radiant Cooler Assembly 57
3.4Electronic Assembly 58
Instrument Control Unit 58
Secondary Processors 59
Modes 59
3.5The Making of SCIAMACHY 59
References 62
Chapter 4: Instrument Operations 63
4.1Sun and Moon Observation 64
Sun Occultation 66
Sub-solar Observations 66
Moon Occultation 67
Refraction 68
4.2Reference Measurement Orbit 68
4.3Mission Scenarios 69
4.4Parameter Tables 70
4.5Measurement States 71
State Definition 71
Nadir and Limb States 72
Occultation States 74
Calibration and Monitoring States 74
4.6Timelines 75
Timeline Concept 75
Timeline Definition 76
4.7SCIAMACHY Operations Setup 76
References 78
Chapter 5: Calibration and Monitoring 79
5.1On-ground Calibration Philosophy 79
5.2The General Calibration Equation 80
5.3Detector Corrections 81
Channels 1-5 (UV-VIS-NIR) 82
Channels 6-8 (SWIR) 84
5.4Wavelength Calibration 84
5.5Stray Light 85
Spectral Stray Light 85
Spatial Stray Light 86
5.6Polarisation 86
5.7Radiometric Calibration 89
5.8Optical Performance Monitoring 90
References 91
Chapter 6: SCIAMACHY In-Orbit Operations and Performance 92
6.1 Commissioning Phase 92
Engineering Tasks 93
Measurement Tasks 94
The SODAP Sequence 94
The Validation Sequence 95
6.2 Routine Operations Phase 95
Operation Change Requests and Final Flight Configuration 97
6.3 Optical Performance 98
Optical Throughput 98
Scan Angle Dependence 100
Light Leak in Channel 7 101
Spatial Stray Light in Limb Measurements 102
6.4 Thermal Performance 103
Ice on Detectors 7 and 8 103
Decontamination 103
Active Thermal Control 104
Thermal Control 105
6.5 Line-of-Sight Performance 108
Scanners 108
Extra Mispointing 109
Tangent Height 109
6.6 Mission Extension 110
Orbit Modification 110
Impact on Instrument Performance 112
References 112
Chapter 7: From Radiation Fields to Atmospheric Concentrations - Retrieval of Geophysical Parameters 113
7.1 Radiative Transfer in the Earth´s Atmosphere 114
7.2 Nadir Trace Gas Retrieval Schemes 116
DOAS Retrieval 116
Modified DOAS Methods 121
7.3 Cloud and Aerosol Retrieval 121
Cloud Parameters 122
Cloud Fraction (CF) 123
Cloud Top Height (CTH) 125
Cloud Geometrical Thickness (CGT) 125
Cloud Optical Thickness (COT) and Effective Radius (Reff,cld) 125
Cloud Phase Index (CPI) 126
Tropospheric Aerosol Parameters 126
7.4Surface Parameter Retrieval 127
Surface Albedo 127
Land Vegetation 129
Oceanic Biological Activity 129
7.5Inversion Theory 129
7.6Application of Inversion Theory to Limb Retrieval 131
7.7 Derivation of Tropospheric Information 133
Reference Sector Method 134
Limb/Nadir Matching 134
Data Assimilation - The NO2 Example 137
References 137
Chapter 8: Data Processing and Products 142
8.1Operational Processing Overview 143
Level 1b Product 143
Level 1c Product 144
Level 2 Product 144
Processing Chains 144
8.2Operational Level 0-1b Processing 146
Memory Effect and Non-linearity 146
Dark Signal 146
Pixel-to-Pixel Gain and Etalon 148
Dead and Bad Pixel Mask 149
Spectral Stray Light 149
Wavelength Calibration 150
Polarisation 151
Radiometric Correction 151
Sun Mean Reference Spectrum 152
Degradation 152
8.3Operational Level 1b-2 Data Processing 152
Column Densities from Nadir Observations 152
Cloud and Aerosol Parameters in the UV-VIS-NIR for Nadir Observations 153
Profiles from Limb Observations 153
Limb Cloud Detection 156
8.4Scientific and Value-Added Products 156
Scientific Products 156
Value-Added Products 156
References 158
Chapter 9: Validation 159
9.1Validation Strategy 160
Validation Principles 160
Comparison Errors and Representativeness 161
9.2Validation Organisation 162
ESA Validation Structure 162
SCIAVALIG Structure 163
9.3Correlative Measurements 164
Ground-Based Instruments 164
Shipborne Campaigns 167
Airborne Campaigns 167
Balloon-Borne Campaigns 170
Satellite Intercomparisons 171
9.4 Validation Results 172
Level 1 Irradiance and Reflectance UV-VIS-NIR-SWIR 173
Level 2 Products from Nadir UV-VIS-NIR 174
Level 2 Products from Nadir SWIR 176
Level 2 Products from Limb UV-VIS 178
References 183
Chapter 10: SCIAMACHY´s View of the Changing Earth´s Environment 186
10.1Tropospheric Composition - Greenhouse Gases 187
Carbon Dioxide - CO2 187
Methane - CH4 187
Water Vapour - H2O 188
Heavy Water - HDO 189
Absorbing Aerosol Index and Precipitation 189
10.2Tropospheric Composition - Reactive Gases 192
Nitrogen Dioxide - NO2 192
Sulphur Dioxide - SO2 196
Formaldehyde (HCHO) and Glyoxal (CHOCHO) 196
Carbon Monoxide - CO 198
Tropospheric Halogen Oxides - BrO and IO 200
10.3The Stratospheric Ozone Layer 202
Ozone - O3 203
Chlorine Dioxide - OClO 208
Bromine Oxide - BrO 210
Polar Stratospheric Clouds - PSC 211
10.4The Upper Atmosphere and Solar Activity 211
Noctilucent Clouds - NLC 212
Mesospheric Ozone and the October/November 2003 Solar Storm 214
Mesopause Temperatures, Thermospheric NO and Metal Layers 215
Observing the Active Sun - The Mg II Index 218
10.5The Earth Surface and Beneath 220
Land Vegetation Characteristics 220
Oligotrophic Oceanic Regions 221
Oceanic Phytoplankton Characteristics 221
10.6SCIAMACHY and the Goddess of Love 221
References 224
Appendix 228
Atmospheric Gases 228
Abbreviations and Acronyms 228
Index 234