Gross primary productivity estimation using multi-angular measurements from small satellite clusters

Gross primary productivity is an excellent metric of how much forests act as carbon dioxide sinks but currently have up to 40% uncertainty in their global estimates. A large proportion of the uncertainty has been attributed to artifacts in the sun-sensor geometry of monolithic spacecrafts leading to insufficient sampling of the bi-directional reflectance of vegetation. This paper proposes to use small satellite clusters with spectrometers as a new measurement solution to improve angular sampling locally and scale up measurements globally. Initial observing system simulations with four satellites launched as secondary payloads via the ISS and operating in different imaging modes show error estimates of less than 12% when compared to dense airborne measurements, a 50% improvement to the worst case error produced by corresponding monoliths.

[1]  Thomas Hilker,et al.  Data assimilation of photosynthetic light-use efficiency using multi-angular satellite data: I. Model formulation , 2011 .

[2]  Sreeja Nag,et al.  Design of Nano-satellite Cluster Formations for Bi-Directional Reflectance Distribution Function (BRDF) Estimations , 2013 .

[3]  T. A. Black,et al.  A modeling approach for upscaling gross ecosystem production to the landscape scale using remote sensing data , 2008 .

[4]  Thomas Hilker,et al.  PHOTOSYNSAT, photosynthesis from space: Theoretical foundations of a satellite concept and validation from tower and spaceborne data , 2011 .

[5]  Feng Gao,et al.  Use of In Situ and Airborne Multiangle Data to Assess MODIS- and Landsat-based Estimates of Surface Albedo , 2012 .

[6]  E. Vermote,et al.  Airborne spectral measurements of surface-atmosphere anisotropy for several surfaces and ecosystems over southern Africa , 2001 .

[7]  T. A. Black,et al.  Inferring terrestrial photosynthetic light use efficiency of temperate ecosystems from space , 2011 .

[8]  Michael D. King,et al.  Simultaneous retrieval of aerosol and surface optical properties from combined airborne- and ground-based direct and diffuse radiometric measurements , 2009 .

[9]  Thomas Hilker,et al.  Data assimilation of photosynthetic light-use efficiency using multi-angular satellite data: II Model implementation and validation , 2012 .

[10]  R. B. Jackson,et al.  CO 2 emissions from forest loss , 2009 .

[11]  N. Coops,et al.  Multi-Angle Remote Sensing of Forest Light Use Efficiency , 2007 .

[12]  Michael D. King,et al.  Multiwavelength scanning radiometer for airborne measurements of scattered radiation within clouds , 1986 .

[13]  T. A. Black,et al.  Separating physiologically and directionally induced changes in PRI using BRDF models , 2008 .

[14]  F. E. Nicodemus Directional Reflectance and Emissivity of an Opaque Surface , 1965 .

[15]  O. de Weck,et al.  Relative trajectories for multi-angular earth observation using science performance optimization , 2014, 2014 IEEE Aerospace Conference.

[16]  Corinne Le Quéré,et al.  Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks , 2007, Proceedings of the National Academy of Sciences.

[17]  Georgi T. Georgiev,et al.  Evaluation of Hyperspectral Snapshot Imagers onboard Nanosatellite Clusters for Multi-Angular Remote Sensing , 2013 .

[18]  David J. Harding,et al.  Amazon forests maintain consistent canopy structure and greenness during the dry season , 2014, Nature.