Chung-Chi Lin

BIOMASS: A P-band SAR earth explorer core mission candidate

The greatest uncertainties in the global carbon cycle involve estimating how carbon dioxide is taken up by land. The BIOMASS mission aims to improve the present assessment and future projection of the terrestrial carbon cycle by providing consistent global maps of forest biomass and forest area, forest disturbances and recovery with time, and the extent and evolution of the forest flooding. The BIOMASS primary objectives can be achieved through P-band (435MHz) synthetic aperture radar (SAR) observations of global forest cover. Two parallel industrial studies at phase 0 level were awarded respectively to Astrium GmbH and Thales Alenia Space Italy. This paper presents the resulting system concepts as elaborated by the industrial teams. The result of the phase 0 was presented to the user community in January 2009 in Lisbon together with other Earth Explorer candidates for further down-selection. If successfully selected after phase 0 and phase A, BIOMASS will be launched during 2016.

ESA future earth observation explorer missions

A new call for Core Earth Explorer Ideas was released by the European Space Agency in March 2005. The Call focused on the global carbon and water cycles, atmospheric chemistry and climate, as well as the human element as a cross cutting issue. The proposals were peer reviewed by scientific panels, and also appraised technically and programmatically by ESA. This paper describes the Earth Explorer cycle and gives an overview of the six candidate missions selected for assessment studies.

The Biomass mission, status of the satellite system

Earth Explorers are the backbone of the science and research element of European Space Agency (ESA)s Living Planet Programme, providing an important contribution to the understanding of the Earth system. Following the User Consultation Meeting held in Graz, Austria on 5-6 March 2013, the ESA Program Board has decided implementing Biomass as the 7th Earth Explorer Mission within the frame of the ESA Earth Observation Envelope Programme. This paper will give an overview of the satellite system and its payload. The system technical description presented here is based on the results of the work performed during parallel Phase A system studies by two industrial consortia led by Airbus Space and Defence Ltd. and Thales Alenia Space Italy. Two implementation concepts (respectively A and B) are described and provide viable options capable of meeting the mission requirements.

P-band radar ice sounding in Antarctica

In February 2011, the Polarimetric Airborne Radar Ice Sounder (POLARIS) was flown in Antarctica in order to assess the feasibility of a potential space-based radar ice sounding mission. The campaign has demonstrated that the basal return is detectable in areas with up to 3 km thick cold ice, in areas with up to several hundred meters thick warm shelf ice, and in areas with up to 700 m thick crevassed glacier ice. However, major gaps in the basal return are observed, presumably due to excessive absorption, scattering from ice inclusions in the firn, low basal reflectivity, and the masking effect of the surface clutter. Internal layers are observed down to depths exceeding 2 km. The polarimetric data show that the internal layers are strongly anisotropic at a ridge, where the ice flow is supposed to be highly unidirectional. In case of space-based ice sounding, the antenna pattern cannot offer sufficient surface clutter suppression, but improved clutter suppression has been demonstrated with novel multi-phase-center techniques.

Biomass, CoReH 2 O, PREMIER: ESA's candidate 7 th Earth Explorer Missions

The European Space Agency (ESA) released a Call for Proposals for the next Earth Explorer Core Mission in March 2005, with the aim to select the 7th Earth Explorer (EE-7) mission for launch in the next decade [1]. Twenty-four proposals were received and subject to scientific and technical assessment. Six candidate missions were selected and further investigated in the preliminary feasibility studies (Phase 0). A further down-selection was made after the User Consultation Meeting held in Lisbon, Portugal in January 2009. Three candidate missions were selected for further feasibility investigations (phase A). Each of the candidate missions is now being defined in detail through two parallel and competing industrial studies and many complementary science and technology studies, aiming to the final down-selection in 2011/12, followed by the mission implementation with a planned launch in the 2016/17 timeframe.

ESA's biomass mission candidate system and payload overview

The European Space Agency (ESA) is preparing candidates for the next Earth Explorer Core mission with the aim to select the 7th Earth Explorer mission to be launched towards the end of this decade. Earth Explorers are the backbone of the science and research element of ESAs Living Planet Programme, providing an important contribution to the global endeavor of understanding the Earths system, particularly in view of global climate change. Six candidate missions were selected and investigated in the preliminary feasibility studies (Phase 0). A further down-selection was made after the User Consultation Meeting held in Lisbon, Portugal, in January 2009. Three candidate missions (Biomass, CoReH2O and PREMIER) were selected for further feasibility investigations (phase A). Each of the candidate missions has been defined in detail through two parallel and competing industrial studies and many complementary science and technology studies, aiming to the final down-selection in 2013, followed by the mission implementation with a planned launch in 2019. This paper will give an overview of the observation requirements, satellite system, payload and general status of the Biomass mission.

ESA future Earth observation Explorer missions

A new call for Core Earth Explorer Ideas was released by the European Space Agency in March 2005. The Call focused on the global carbon and water cycles, atmospheric chemistry and climate, as well as the human element as a cross cutting issue. The proposals were peer reviewed by scientific panels, and also appraised technically and programmatically by ESA. This paper describes the Earth Explorer cycle and gives an overview of the six candidate missions selected for assessment studies.

Active Microwave Scattering Signature of Snowpack—Continuous Multiyear SnowScat Observation Experiments

European Space Agencys SnowScat instrument is a real aperture scatterometer which was developed by Gamma Remote Sensing AG. It operates in a continuous-wave mode, covers a frequency range of 9.15-17.9 GHz in a user-defined frequency-step and has a full polarimetric capability. The measurement campaigns were started first in February 2009 at Weissfluhjoch, in Davos, Switzerland, as an initial test of the instrument over a deep alpine snowpack. Physical characterizations of the snowpack and meteorological measurements were carried out, which formed a detailed in situ dataset. SnowScat was then moved to Sodankylä in Finland in early November 2009, a site of the Finnish Meteorological Institute in Lapland. In addition to the in situ snowpack characterizations and meteorological observations, continuous passive microwave observations were also performed. During the 2012-2013 winter period, a vertical time-domain snow profiling experiment was carried out in addition for resolving the scattering contributions from the snow layers of different physical properties. This paper summarizes the results of the SnowScat observations and initial comparisons against the in situ meteorological and snowpack data. The Sodankylä campaign data evidenced the high variability of the radar backscatter behavior of snowpack from year to year, which indicates its strong dependency on changing snow microstructure. Indeed, the snow microstructure is continuously driven by snow metamorphism, which are further affected by meteorological conditions and their interannual variability. The backscattering property of snowpack in the range X- to Ku-band for all polarizations appeared to be dominated by its microstructural morphology and underlying ground conditions, and to a lesser extent by the snow depth, or its snow-water-equivalent.

A rotating, range-gated, fanbeam spaceborne scatterometer concept

A new, simple scatterometer concept combines the advantages of both the fixed, multiple beam, side-looking radar such as AMI-Wind (ERS-1/2) and NSCAT (ADEOS), and the conically scanning pencil-beam radar such as SeaWinds. A wide, fanbeam antenna is rotated around a vertical axis with a slow rotation rate. For a satellite at an altitude of 725 km, the antenna footprint sweeps a circular donut of 1500 km diameter. Such a slow conical scan combined with the motion of the satellite at /spl sim/7 km/s ground-speed results in highly overlapping successive sweeps such that an image pixel is revisited up to 10 times during an overpass. The pixels in the radial direction are resolved by range-gating the radar echo. Depending on the across-track position of the imaged pixel, the measurement acquisitions during an overpass consist of a set of /spl sigma//sup 0/ at different combinations of the azimuth and incidence angles. A preliminary optimisation of the system resulted in a C-band radar concept with a 15 km multiple-look spatial resolution and global coverage in two days. A sketch of the developed concept, preliminary system design and predicted performance are described.

ESA's premier mission candidate: System and payload overview

The European Space Agency (ESA) is preparing candidates for the 7th Earth Explorer Core mission with the aim to select one of them to be launched towards the end of this decade. Earth Explorers are the backbone of the science and research element of ESAs Living Planet Programme, providing an important contribution to the global endeavour of understanding the Earth system, particularly in view of global climate change. Six candidate missions were selected and further investigated in the preliminary assessment studies (Phase 0). A further down-selection was made after the User Consultation Meeting held in Lisbon, Portugal in January 2009. Three candidate missions (Biomass, CoReH2O and PREMIER) were selected for further feasibility investigations (Phase A). Each of the candidate missions has been defined in detail through two parallel and competing industrial studies and many complementary science and technology studies, aiming to the final down-selection in 2013, followed by the mission implementation with a planned launch in 2019. This paper will give an overview of the observation requirements, satellite, payload and general status of the PREMIER mission.