Soil Moisture and Ocean Salinity (SMOS)

The SMOS satellite was launched on 2nd November 2009, making it the first satellite to provide continuous multi-angular L-band (1.4GHz) radiometric measurements over the globe. Over continental surfaces, SMOS provides near-surface soil moisture data at ~50km resolution with a repeat cycle of 2-3 days. The payload is a 2D interferometer yielding a range of incidence angles from 0° to 55° at both V and H polarisations, and a 1,000km swath width. Its multi-incidence angle capability is expected to assist in determining ancillary data requirements such as vegetation attenuation. This satellite has a 6:00am/pm equator overpass time (6:00am local solar time at ascending node). Due to the synthetic aperture approach of this satellite, brightness temperature observations will be processed onto a fixed hexagonal grid with an approximately 12km node separation. While the actual footprint size will vary according to position in the swath, incidence angle etc., it will be approximately 42km diameter on average. The features of SMOS are summarized below. SMOS data can be downloaded from ESA.