TIMESAT - a Program for Analyzing Time-Series of Satellite Sensor Data. Users Guide for TIMESAT 2.3

• Time-series of vegetation index derived from satellite spectral measurements can be used to gain information on seasonal vegetation development. This information aids analyzes of the functional and structural characteristics of the global and regional land cover and adds to our current knowledge of global cycles of energy and matter. Long time-series of vegetation index data can also provide information on shifts in the spatial distribution of bio-climatic zones, indicating variations in large-scale circulation patterns or land-use changes. Although the value of remotely sensed time-series data for monitoring vegetation seasons has been firmly established, only a limited number of methods for exploring and extracting seasonality parameters from such data series exists. For this reason the TIMESAT program package for extracting seasonal parameters has been developed. The program uses an adaptive Savitzky-Golay filtering method and newly developed methods based on upper envelope weighted fits to asymmetric Gaussian and double logistic model functions (Jönsson and Eklundh, 2002, 2003, 2004). From the fitted model functions a number of phenological parameters, e.g. beginning and end of the growing season, can be extracted. The TIMESAT program is tested with the 8 km by 8 km pixel resolution Pathfinder AVHRR Land (PAL) data set generated by NASA/NOAA and the 250 m by 250 m pixel resolution Terra/MODIS data. Being a completely general program TIMESAT can handle also other types of data such as meteorological index and fire data (Verbesselt et al, 2006).

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

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