Validation of MODIS and GEOV2 Leaf Area Index (LAI) Products over Croplands in Northeastern China

The objective of this study is to validate the recent moderate resolution leaf area index (LAI) products generated by MODIS collection 6 (C6) and Geoland2/BioPar project (GEOV2) over major agricultural croplands. Field campaigns were conducted and seasonal continuous LAI measurements were obtained over rice, maize, soybean, and sorghum fields in the Honghe farm (2012 and 2013) and Hailun city (2016) in northeastern China. High resolution 30 m LAI maps were first derived from HJ-1 and Landsat with a look-up table (LUT) method and evaluated with ground-based measurements (R2≥0.67 and RMSE≤0.90). Consequently, the high resolution LAI was upscaled and compared with the moderate resolution LAI products. The results indicate that both MODIS and GEOV2 capture a consistent seasonal pattern of the crop LAI variation. The moderate resolution LAI products are very closed related to the upscaled high resolution reference LAI.