Authors / CoAuthors
Li, F. | Jupp, D.L.B. | Thankappan, M. | Lymburner, L. | Mueller, N. | Lewis, A. | Held, A.
Abstract
Steep terrain affects optical satellite images through both irradiance and BRDF effects. To obtain corrected land surface reflectance and detect land surface change through time series analysis over rugged surfaces, it is necessary to remove or reduce the topographic effects. In this paper, a physical based BRDF and atmospheric correction model for both flat and sloping surfaces in conjunction with the 1-second SRTM (Shuttle Radar Topographic Mission) derived DSM product was applied to conduct BRDF, atmospheric and terrain correction. The model was applied to 8 Landsat scenes covering different seasons and terrain types in eastern Australia. Initial visual assessment showed that the algorithm removed much of the topographic effect and detected deep shadows in all 8 images. Indirect validation based on the change in correlation between the data and terrain slope showed that the correlation coefficient between the surface reflectance factor and the cosine of the incident (sun) angle reduced dramatically after the topographic correction algorithm was applied. The correlation coefficient typically reduced from 0.80 to 0.02 in areas of significant relief. The terrain corrected surface reflectance can also provide suitable input data for multi-temporal land cover classification in areas of high relief based on spectral signatures and spectral albedo, while the products based only on BRDF and atmospheric correction cannot. To ensure stability of the terrain corrected reflectance products when expert intervention in the processing workflow needs to be minimal, the paper also shows the need for additional constraints and calibration the correction algorithm. For example, to avoid overcorrection, the algorithm currently applies an angle threshold to both the BRDF model and the direct irradiance. Above all, the accuracy and effectiveness of the product is shown to depend particularly on the quality of the DSM data, its co-registration with the Landsat data and its spatial resolution.
Product Type
nonGeographicDataset
eCat Id
72766
Contact for the resource
Custodian
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
-
- External PublicationScientific Journal Paper
- ( Theme )
-
- topography
- Australian and New Zealand Standard Research Classification (ANZSRC)
-
- Earth Sciences
-
- Published_Internal
Publication Date
2012-01-01T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
unknown
Topic Category
geoscientificInformation
Series Information
Lineage
Unknown
Parent Information
Extents
Reference System
Spatial Resolution
Service Information
Associations
Downloads and Links
Source Information
Source data not available.