Foreword ........................................................ I
Table of content .............................................. III
List of figures ............................................... XII
List of tables ................................................. XI
German summary (Zusammenfassung) ............................. XIII
1 Introduction ................................................. 1
2 Photosynthesis and carbon assimilation ....................... 7
2.1 Chlorophyll and photosynthesis .......................... 8
2.2 Chlorophyll in the electromagnetic spectrum ............ 10
2.3 Carbon assimilation .................................... 11
2.3.1 The Calvin cycle ................................ 11
2.3.2 The C4 pathway .................................. 13
2.3.3 C3 versus C4 plants ............................. 14
2.4 The C3 plant wheat (Triticum spp) ...................... 14
2.5 The C4 plant maize (Zea mays L.) ....................... 15
3 Test area and field measurements ............................ 17
3.1 Test area Gilching ..................................... 17
3.1.1 Geomorphology/Geology ........................... 18
3.1.2 Land cover ...................................... 19
3.1.3 Climate ......................................... 20
3.1.4 Test fields ..................................... 23
3.2 Field campaigns and acquired data ...................... 24
3.2.1 Plant parameter ................................. 24
3.2.1.1 Phenological status .................... 25
3.2.1.2 Plant height ........................... 26
3.2.1.3 Canopy density ......................... 26
3.2.1.4 Biomass ................................ 27
3.2.1.5 Chlorophyll content .................... 28
3.2.1.6 Leaf area .............................. 29
3.3 Field spectrometry ..................................... 30
3.4 Photographic documentation ............................. 32
3.5 Sampling results ....................................... 32
3.5.1 Wheat ........................................... 33
3.5.1.1 Sampling results - chlorophyll
contents per mass ...................... 33
3.5.1.2 Sampling results - chlorophyll
contents per area ground surface ....... 35
3.5.2 Maize ........................................... 37
3.5.2.1 Sampling results - chlorophyll
contents per mass ...................... 37
3.5.2.2 Sampling results - chlorophyll
contents per unit ground surface ....... 39
3.6 Evaluation of the results .............................. 41
4 Remote sensing data ......................................... 43
4.1 Multi-angular remote sensing ........................... 43
4.2 CHRIS/PROBA-1 .......................................... 45
4.2.1 Acquired data ................................... 47
4.2.2 Radiometric processing .......................... 48
4.2.3 Geometric processing ............................ 50
4.3 AVIS ................................................... 51
4.3.1 Acquired data ................................... 53
4.3.2 Radiometric processing .......................... 54
4.3.3 Geometric processing ............................ 55
5 Monitoring of canopy chlorophyll status ..................... 57
5.1 Reflectance anisotropy of vegetation canopies .......... 57
5.2 Derivation of top-of-canopy chlorophyll ................ 60
5.2.1 Existing approaches ............................. 60
5.2.2 The chlorophyll absorption integral CAI ......... 62
5.3 Derivation of sun and shade chlorophyll using CHRIS
data ................................................... 63
5.3.1 Wheat ........................................... 64
5.3.2 Maize ........................................... 67
5.3.3 Evaluation of the results ....................... 69
5.4 Assessment of chlorophyll distribution maps ............ 70
5.5 Transfer of results to AVIS data ....................... 71
6 Vegetation biophysics in the physically-based SVAT model
PROMET ...................................................... 75
6.1 Modelling of the C3 pathway ............................ 76
6.2 Modelling of the C4 pathway ............................ 78
6.3 Input data ............................................. 79
6.4 PROMET results ......................................... 80
6.4.1 Wheat 2004 ...................................... 80
6.4.2 Wheat 2005 ...................................... 82
6.4.3 Maize 2004 ...................................... 84
6.4.4 Maize 2005 ...................................... 86
6.5 Concluding remarks ..................................... 87
7 Assimilation of remotely sensed chlorophyll in PROMET ....... 89
7.1 Chlorophyll and leaf absorptance ....................... 89
7.2 Results using dynamised leaf absorptance ............... 91
7.2.1 Wheat 2004 ...................................... 91
7.2.2 Wheat 2005 ...................................... 96
7.2.3 Maize 2004 ..................................... 100
7.2.4 Maize 2005 ..................................... 103
8 Synthesis .................................................. 107
8.1 Distribution of chlorophyll within vegetation
canopies .............................................. 107
8.2 Monitoring of vertical chlorophyll distribution
using hyperspectral, multi-angular remote sensing ..... 108
8.3 Sensor dependency of the results ...................... 109
8.4 Chlorophyll and quantum yield ......................... 110
8.5 Assimilation of spatially distributed chlorophyll
data in PROMET ........................................ 110
9 References ................................................. 113
Appendix
List of symbols, variables and constants ................... 125
List of plant and soil parameters used in PROMET ........... 127
Glossary ...................................................... 129
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