Collaborative research project pre agro

Size: px

Start display at page:

Download "Collaborative research project pre agro"

Augustine Dixon
7 years ago
Views:

1 Collaborative research project pre agro Extraction of phenology-dependent structural information from hyperspectral, directional CHRIS data for a better derivation of canopy parameters of winter-wheat Vista Geowissenschaftliche Fernerkundung GmbH Silke Begiebing, Heike Bach, Wolfram Mauser

directional CHRIS data for a better derivation of canopy parameters of

2 Content The preagro project Overview on hyperspectral remote sensing data and test-sites Concept of the model based analyses Derivation of canopy parameters Resulting maps for green LAI and fraction of senescent material Validation Summary and first results of data assimilation into the crop growth model 2

$parameters Resulting maps for green LAI and fraction of senescent material$

3 The preagro project preagro is a German project for joint research and development of basics for precision agriculture: Information driven crop production with precision farming as the central scientific and technical precondition for a sustainable development of agricultural land use. 3

crop production with precision farming as the central scientific and

4 The preagro project Preagro is Germany s largest activity in the field of precision agriculture coordinated by Dr. A. Werner, ZALF Funded by the German Federal Ministry of Education and Research VISTA is in charge for remote sensing applications of hyperspectral data using Multitemporal directional CHRIS observations Multitemporal airborne hyperspectral measurements using the AVIS sensor 4

Werner, ZALF Funded by the German Federal Ministry of Education and Research VISTA is in charge

5 Overview on the hyperspectral remote sensing data CHRIS Sun AVIS North Used for derivation of... plant structure green Leaf Area Index fraction of mature material Ground Track Available ground truth: soil maps biomass measurements Used for derivation of... green Leaf Area Index fraction of mature material upscaling analyses LAI measurements with LICOR 2000 yield maps

$.. plant structure green Leaf Area Index fraction of mature material Ground Track Available$

6 Suitable CHRIS data 2005 / 2006 Year Date Test-site Phenological state 2005 Apr 04 Wulfen / Baasdorf Tillering wheat Jun 19 Wulfen / Baasdorf Milk stage wheat Jul 24 Groß-Twülpstedt Used for soil parameterisation Aug 19 Groß-Twülpstedt Used for soil parameterisation 2006 Apr 14 Wulfen / Baasdorf Tillering wheat Jun 12 Wulfen / Baasdorf Flowering wheat Sep 07 Wulfen / Baasdorf Milk stage maize Jun 13 Groß-Twülpstedt Flowering wheat Jul 10 Groß-Twülpstedt Milk stage wheat 6

Used for soil parameterisation 2006 Apr 14 Wulfen / Baasdorf Tillering wheat Jun 12 Wulfen / Baasdorf Flowering wheat

7 Test-site Wulfen / Baasdorf CHRIS data: 36m ground resolution (Mode 1) Air-borne data: 2m ground resolution 7 Red edge - color composit

8 Test-site Groß-Twülpstedt CHRIS data: 18m ground resolution (Mode 5) AVIS data: 4m ground resolution 8

9 Example of a coupled ecosystem and radiative transfer model Daily simulation of LAI and biomass accumulation Daily simulation of reflectance 9

10 Derivation of plant parameters for a single spectrum 10 Comparison of simulated and measured reflectance Parameter adjustment

11 Spatial demonstration of parameter retrieval Measured spectral patterns Step-wise model approximation 11

12 Four-Stream Radiative Transfer Model SLC (Verhoef & Bach 2003) Input parameters: Fluxes considered : 1. Direct solar flux 2. Diffuse downward flux 3. Diffuse upward flux 4. Direct observed flux (radiance) Solar zenith angle Observation zenith angle Relative azimuth angle Fraction diffuse sky irradiance Soil BRDF parameters (b, c, B0, h) Dry soil reflectance spectrum Soil moisture Leaf chlorophyll Leaf water Leaf dry matter Leaf mesophyll structure LAI leaf area index Leaf angle distribution Hot spot parameter Fraction of mature material Dissociation factor: green / brown Crown coverage 12

Direct observed flux (radiance) Solar zenith angle Observation zenith angle Relative azimuth angle Fraction diffuse sky irradiance Soil BRDF

13 BRDF sensitivity to average leaf angle Spectral changes at 5 observation zenith angles with structural change 13 SLC input: green LAI = 4 reflectance [%] wavelength [µm] 80 Average leaf angle

green LAI = 4 reflectance [%] 60 50 40 30 20 10-55 -36 0 +36

14 BRDF sensitivity analyses change of leaf angle (modelled) SLC input: total LAI = 4 CHRIS, Jun 21th 05 maturing (measured) 14 BRDF factor related to nadir observer zenith [ ] % 70 fb % 80 fb BRDF at 780nm simulated for different leaf angles BRDF factor related to nadir observer zenith [ ] green maturing senescent BRDF at 780nm measured at different monitoring points

8-60 -60-40 -20-20 0 20 40 60 observer zenith [ ] 60 60 70 + 50% 70 fb 80 + 80% 80 fb BRDF at 780nm simulated for

15 Structural change with phenology Structure changes as dominance of stems and heads increases with maturing Jun 20th 05 Jul 7th 05 CONSTANT Average angle leaves: 52 Average angle heads & stems: 82 VARIABLE Average leaf angle over canopy:? 15

20th 05 Jul 7th 05 CONSTANT Average angle leaves: 52

16 Derivation of structure from directional CHRIS data CHRIS data Jun 19th 2005 during maturing process Inversion of SLC using all 5 observation zeniths for different leaf angles Result: Linear coupling between fraction of mature material and leaf angles: 0% senescent average leaf angle % senescent average leaf angle 78 16

$63 67 70 74 78 Result: Linear coupling between fraction of mature material and leaf$

17 Winter wheat, comparison between AVIS and CHRIS acquisitions (Jun 19th/21th 2005) Shown area: approx. 130ha Visible color composit 17

18 Derived fraction of mature material and green LAI from CHRIS data (Jun 19th) 18

19 Derivated fraction of mature material and green LAI from AVIS data (Jun 21th) 19

20 Validation of the derived parameters (airborne data) Fraction of mature material Green / Total LAI modelled fraction of mature material [%] fraction of mature material from photo analyses [%] modelled green LAI [m²/m²] RMSE = 15.5% y = x R 2 = Licor LAI measurements [m²/m²]

$05 80 60 40 20 0 0 20 40 60 80 100 fraction of mature material from photo analyses [%] 22.06.$

21 Summary Green Leaf Area Index as well as fraction of mature material could successfully be retrieved from airborne and spaceborne hyperspectral remote sensing data Incorporation of phenological development is important for correct structural parametrisation; this was accomplished by using the directional CHRIS data Work in progress: data assimilation into the crop growth model PROMET-V for yield modelling 21

22 First assimilation into crop growth model 30 : : 90 Average measured yield : 65 dt/ha Average modelled yield : 45 dt/ha 22

23 Acknowledgements Thanks to support by BMBF within the project PreAgro (FK )...and to you for your attention! Contact: Silke Begiebing, Dr. Heike Bach Vista Geowissenschaftliche Fernerkundung GmbH Gabelsbergerstr.51, München, Germany ++49 (0)89 / Begiebing@vista-geo.de, Bach@vista-geo.de 23

24 Ableitung der Blattwinkel aus Fotos mittl. Wkl. mittl. Wkl. Blätter Stiele/Ähren Winkel Juni: Mittelwert insg.: Mittelwert Grün: Mittelwert Braun: Monitoringpunkt 3 Schlag 141, Foto von TP14 Winkel Juli: Mittelwert insg.: Mittelwert Grün: Mittelwert Braun:

25 TP 13: Gekoppelte Modellierung Hyperspektraldaten Meteodaten, Landnutzung, GIS-Info Geobiophysikal. Karten Beobachtetes Reflexionsspektrum Modelliertes Reflexionsspektrum Kalibrierung & Atmosphärenkorrektur Inversion von SLC Anpassung von LAI, Chlorophyll, Bestandesreflexionsmodell SLC Plausible Wertebereiche Optimierung interner Modellparameter Bestandswachstumsmodell PROMET-V Simulierter LAI, Chlorophyll, Aus Fernerkundung abgeleiteter LAI, Chlorophyll,... Biomasse, Kornertrag, N-Aufnahme Pflanzenwasser... 25

26 Fotoanalyse I Anteil seneszenten Materials aus Photoanalyse Spectral index green senescent 16,5% fraction mature Monitoringpunkt 3 Schlag 141, Foto von TP14 26

27 BRDF sensitivity analyses BRDF change with maturing SLC input: total LAI = 4 CHRIS, Jun 21th BRDF factor related to nadir observer zenith [ ] % 70 fb % 80 fb BRDF at 780nm simulated for different leaf angles BRDF factor related to nadir observer zenith [ ] green maturing senescent BRDF at 780nm measured at different monitoring points

28 Overview on the hyperspectral remote sensing data CHRIS Sun AVIS North Used for derivation of... plant structure green Leaf Area Index Fraction of mature material Ground Track Sensitive for: green leaf area index fraction of mature material chlorophyll content Used for derivation of... green Leaf Area Index Fraction of mature material upscaling analyses plant water content plant structure

29 29 Correlation to yield measurements modellierter grüner LAI [m²/m²] y = x R 2 = Modelled green LAI [m²/m²] Yield [dt/ha] Ertrag Yield [dt/ha] good basis for yield modelling

ANALYSIS OF HYPERSPECTRAL FIELD DATA FOR DETECTION OF SUGAR BEET DISEASES

ANALYSIS OF HYPERSPECTRAL FIELD DATA FOR DETECTION OF SUGAR BEET DISEASES Rainer LAUDIEN*, Georg BARETH**, Reiner DOLUSCHITZ*** Department of Agricultural Economics Division: Agricultural Informatics and