If we are interested in the analysis of land surface phenology and the coupling of these remotely sensed observations with ground observations, it may not be necessary to learn specialized (and relatively expensive) remote sensing software packages. A freely available online application (tethys.dges.ou.edu) was developed by us to enable the monitoring of land surface phenology over North America. The application allows for the selection of one 0.05° by 0.05° area based on a Google Earth map anywhere within North America. Upon selection of an area, the application then reveals the average land surface phenology of all available years (currently 2000 – 2011) based on phenology derived from the MODIS Nadir BRDF-Adjusted Reflectance (NBAR; MOD43C3). The user can request standard errors, to better understand temporal variability, and analyze the phenological development of the current year (now 2012) to better understand the development of an ongoing year compared to previous years.
The user can experiment with different thresholds for the midpoint NDVI method which was found to be one of the most accurate methods in a large model evaluation study (White et al. 1997; White et al. 2009). The users can explore the effect of the different thresholds for the estimation of the start and the end of the growing season. Data can be exported as jpg files and the time series can be copied over to spreadsheet programs. A similar application is available to compare the standard vegetation indices NDVI and EVI.