Future Earth Explorer Missions   Main elements that build up the complex Earth System.   The objective of the candidate Earth Explorer BIOMASS mission is to acquire global measurements of forest biomass to assess terrestrial carbon stocks and fluxes. The mission is envisaged as a novel spaceborne P-band synthetic aperture polarimetric radar operating at 435 MHz and 6 MHz bandwidth.   The CoReH2O mission concept aims to fill the gaps in current information on snow, glaciers and surface water. The concept employs twin frequency synthetic aperture radars (9.6 and 17.2 GHz) in two consecutive mission phases to deliver all-weather, year-round information on regional and continental-scale snow-water equivalent.   The PREMIER mission aims to advance our understanding of the processes that link trace gases, radiation and chemistry in the upper troposphere and lower stratosphere. The instrumentation will consist of an infrared limb-imaging spectrometer and a millimetre-wave limb-sounder. Last update: 26 November 2010