1. Preliminary Design Review of NSF project: STAR-Light – a 1
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

2. Background: There are 2 drivers for this project
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
REBEX-3
Toolik Lake
Alaska
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

3. 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

4. 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

5. Science Requirements for STAR-Light
Flight Direction
0.7 l
0.445 m
1.4 GHz, 10-element, H-pol aperture synthesis radiometer
Angular resolution: < 20o with > 90% beam efficiency
NET < 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

6. Future Satellite System
Sketch of the ESA Soil Moisture Ocean Salinity (SMOS) satellite

7. STAR-Light Organization