Land Surface Monitoring from the Moon

Transcription

1 Land Surface Monitoring from the Moon Jack Mustard, Brown University Workshop on Science Associated with Lunar Exploration Architecture

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3 Unique Perspective of Lunar Observation Platform Low Earth Orbit: sun synchronous Geostationary: same hemisphere of the Earth Fixed emergence, changing incidence angle Lunar rotating planet with changing incidence and emergence angles (phases) 28 day repeat of illumination conditions

4 Priorities of NRC Decadal Survey for Land-Use Change, Ecosystem Dynamics and Biodiversity Mission Variables Sensor Coverage Spatial resolution Frequency Ecosystem Function Ecosystem structure and biomass Vegetation properties (species, NPP, disturbance) Coral Reef health Vegetation height, structure Hyperspectral LIDAR, Radar Global, pointable Global m m 30 day, pointable Monthly Carbon Budget CO2 mixing ratio, CO concentrations Active LIDAR Global 100 m strips Diurnal, assimilated every 24 hrs Coastal Ecosystems Water color Hyperspectral Western Hemisphere 250 m Multiple daily Global Ocean Productivity Water color Hyperspectral Global 1 km 2-day global coverage

5 Land Surface Monitoring BRDF from MODIS Sensors Global mapping of surface albedo measures Parameterize global climate and biogeochemical models Initializing numerical weather prediction and mesoscale models Quantifying the surface background for cloud studies Correction of observations for directional effects Nadir BRDF-Adjusted Reflectance (NBAR) standardizes reflectance to a specific view and illumination geometry noon sun, nadir view Characterization of surface scattering behavior Non-Lambertian surface BRDF effects Quantifying the surface anisotropy

6 White-Sky Spectral Albedo 7-22 April, 2002 Schaaf et. al NIR ( ) Red ( ) Blue ( )

7 Land Surface Monitoring Recommendations from ESS Decadal Survey Considered the value of multi-angle remote sensing Capable of retrieving certain ecosystem properties such as ecosystem structure Did not consider it a high priority, and could be accommodated with existing multi-angle sensors (e.g. MISR) But, would be a valuable complement and recommend continued study of the science to be derived from multiangle observations Lunar Observatory would provide a unique perspective and would more completely sample the BRDF for science applications (e.g. near 0 phase (hot spot)

8 Land Surface Monitoring Phenology Timing and magnitude of ecosystem processes indicated by greenness measured as a function of time Integration of this signal a measure of primary and net productivity Interannual variability coupled to climate change over northern latitudes Higher precision in timing or to time events would be beneficial to environmental monitoring

9 Measuring Phenology AVHRR NDVI May 2000 MODIS NDVI May 2000 NDVI Normalized Difference Vegetation Fraction Date

10 A 110 April 20 th Onset 165 June 15 th MODIS Onset Landsat Onset (color scale has changed) Fisher and Mustard, 2006

11 Hyperspectral Hyperspectal sensors bring new ecosystem measurement capability Drought Stress and Carbon Uptake with Hyperion Asner et al., PNAS, 2006 MODIS MS Capability Hyperspectral Capability Spatial resolution of 500 m- 1 km possible with a 1 m telescope

12 Coastal Ocean Monitoring Coastal Ocean requires high SNR, high temporal frequency, and ability to reach into the UV (350 nm) NRC Recommends a geosynchronous hyperspectral sensor to capture events, increase signal to noise, and obtain cloudfree observations A lunar hyperspectral sensor would fulfill some of these requirements but spatial resolution would be a challenge

13 Land Surface Monitoring Cross-calibration of instruments Long-term measurements Bidirectional Reflectance Distribution Function (BRDF) Tracking events Compliment LEO and GEO observations

14 Challenges for Earth Observation Lunar outpost not optimum for Earth observation (frequency of Earth in field of view) For systematic measurement changing viewing conditions present a challenge