6533b859fe1ef96bd12b6fea

RESEARCH PRODUCT

Gridding artifacts on ENVISAT/MERIS temporal series

subject

description

Earth observation satellites are a valuable source of data that can be used to better understand the Earth system dynamics. However, analysis of satellite image time series requires an accurate spatial co-registration so that the multi-temporal pixel entities offer a true temporal view of the study area. This implies that all the observations must be mapped to a common system of grid cells (gridding). Two common grids can be defined as a reference: (1) a grid defined by an external dataset in a given coordinate system or (2) a grid defined by one of the images of the time series. The aim of this paper is to study the impact that gridding has on the quality of ENVISAT/MERIS image time series, which is quantified using a time series of images acquired over The Netherlands. First, the impact of the reference map grid selection is evaluated in terms of geolocation errors and pixel overlap. Then, the effect of observation geometry (due to the fact that images are acquired from slightly different orbits) is studied. Results show that it is of paramount importance to identify areas with small pixel overlap in order to further analyze the reliability of the products derived from these areas.