Evaluating MODIS phenology product for rotating croplands through ground observations

The MODIS global vegetation phenological product (MCD12Q2) has been widely evaluated for forestlands. However, little is reported for croplands. We evaluate the MODIS phenological product during 2001 to 2009 in combination with ground-based phenological data for wheat/maize rotation systems in the North China Plain (NCP). The spatial patterns of phenological dates for winter wheat and summer maize are consistent between MODIS and site-observed data across the NCP. The results show that MODIS phenological dates correlate well with observed phenological dates for both winter wheat (R-2 = 0.90) and summer maize (R-2 = 0.93) at five ground stations, which testified that the MODIS vegetation phenology product can realistically detect the key growing stages of winter wheat (greening, heading, grain-filling, and maturity) and summer maize (emergence, tasseling, grain-filling, and maturity), respectively. Planting areas identified from the MODIS phenology product are also compared with statistical data from 48 administrative zones in 2009. Correlation suggests the acceptance of MODIS identifiable area having R-2 = 0.73, 0.65 for winter wheat - summer maize, respectively. Meanwhile, a slight underestimation in planting area, by 8% for winter wheat and by 5% for summer maize, is found across the NCP. Overall evaluation criteria suggest that the MODIS MCD12Q2 product can provide generally reliable information of crop phenology for double crop areas. c 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)