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Preliminary Design Review of NSF project: STAR-Light – a 1.4 GHz aperture synthesis radiometer for use on light aircraft in arctic land-surface hydrology Science Requirements. Tony England 3 October 2001. Background: There are 2 drivers for this project. REBEX-3 Toolik Lake Alaska
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Preliminary Design Review of NSF project:STAR-Light – a 1.4 GHz aperture synthesis radiometer for use on light aircraft in arctic land-surface hydrologyScience Requirements Tony England 3 October 2001
Background: There are 2 drivers for this project REBEX-3 Toolik Lake Alaska 1994-1995 1) ‘Stored water’ is the most important unmeasured parameter limiting the predictive skills of continental weather and climate models • Estimate daily global stored water at ~10 km resolution • 2) Climate models predict early & significant warming in the Arctic • Thinning of permafrost, drying of active layer,and transition of Arctic from carbon sink to carbon source • Monitor active layer • Duration • Water content
1.4 GHz Radiometer on Light Aircraft Would Facilitate Remote Sensing Hydrology in Arctic • Calibration of Arctic hydrology models require data from thawing in spring to freezing in fall • Arctic is inaccessible to grounds surveys in summer • NASA radiometers fly on 4-engine, turboprop aircraft like the C-130 and P-3 • Operations costs of these aircraft are prohibitive • Operations costs of STAR-Light will be < 5% those of NASA systems enabling season-long field campaigns B.3
STAR-Light Objective: • Build a reliable L-band imaging radiometer for use on light aircraft in Arctic land-surface hydrology Strategy: • STAR technology • Direct Sampling Digital Receivers (DSDR) • Band definition filters in digital domain
0.7 l 0.445 m Flight Direction Science Requirements for STAR-Light • 1.4 GHz, 10-element, H-pol aperture synthesis radiometer • Angular resolution: < 20o with > 90% beam efficiency • NET < 0.1 K desired, < 0.5 K required • Calibration: < 2 K desired, < 3 K required • Linear dynamic range 5 K < Tb < 300 K • Ambient operating range -30o C < To < +40o • Across-track scan to ±35o • Along-track scan + 20o / -50o • Operation on a Super Cub-class aircraft for extended periods in the Arctic STAR-Light element configuration
Future Satellite System Sketch of the ESA Soil Moisture Ocean Salinity (SMOS) satellite