Leaf area index retrieval using IRS LISS-III sensor data and validation of MODIS LAI product over Madhya Pradesh

Results of a study aimed at relating field measurements of leaf area index (LAI) to space-borne IRS LISS-III data, preparation of site-level LAI maps and validation of moderate resolution imaging spectroradiometer (MODIS)-based 1 km LAI global fields, conducted over agricultural areas of Bhopal and Indore during winter season of 2001–02 are presented. Measurements of field-level LAI, aerosol optical thickness and water vapour were carried out on the day of satellite overpass for three dates for each site. Empirical models based on site-specific LAI–vegetation index relations were developed and used to generate 23 m resolution LAI maps. These LAI images covering approximately 30 km × 30 km were aggregated to 1 km spatial resolution and used for validation of MODIS LAI product. The results indicated significant positive correlation between LAI derived from LISS-III data and MODIS data, with an overestimation in the MODIS product, root mean square error of 0.92 to 1.26 for the Bhopal site and 0.20 to 0.33 for the Indore site.