Attachment A.pdf

Attachment A: Sustainable Land Imaging (SLI) Mission Objectives and Requirements

MAJOR MISSION OBJECTIVES:

• Collect and archive moderate-resolution, reflective and thermal multispectral image data affording seasonal coverage of the global land mass for a period of no less than 5 years;

• Ensure that Sustainable Land Imaging (SLI) data are sufficiently consistent with data from Landsat-9, in terms of acquisition geometry, revisit rates, calibration, radiometric performance, coverage characteristics, spectral and spatial characteristics, output product quality, and data availability to permit studies of land cover and land use change and nearshore coastal and fresh waters over a multi-decadal period;

• Distribute standard (and archived) Landsat products to users on a non-discriminatory basis and at no cost to the users with an approximate six-hour latency.

REQUIREMENTS:

In order to meet the standards of the Landsat program's data archive, the SLI data acquired over the entire mission lifetime need to be sufficiently consistent with operational Landsat-9 data requirements, in terms of acquisition geometry (sensor view angles < 7.5 ± 2 degrees), revisit rates, calibration, coverage characteristics, spectral and spatial characteristics, radiometric performance/stability, output product quality and data availability, to enable and sustain long-term, consistent detection and quantitative characterization of changes on the global land/water surface. This requirement is consistent with the directions and guidance provided in the Land Remote Sensing Policy of 1992 (U.S. Code Title 15, Chapter

82) and the National Plan for Civil Earth Observations (Section 6.1.2).

SPATIAL/SPECTRAL/TEMPORAL

a) SLI shall operate and meet all baseline requirements for a period of at least 5 years for shortwave reflective bands 1-9 and longwave thermal bands 10-11 as specified in Table 1;

b) SLI shall image areas centered on the Earth's equator at a mid-morning local solar time, 10:00 a.m. ± 15 minutes;

c) SLI shall be capable of imaging any sun-lit area within the Landsat-9 coverage area at least once every

16 days;

d) SLI shall provide for simultaneous imaging of four visible spectral bands, one near-infrared spectral band, three short-wave-infrared spectral bands at 30 meters spatial resolution or better (at nadir), one panchromatic band at 15 meters spatial resolution or better (at nadir) and two thermal bands at 100 meters spatial resolution or better (at nadir) as specified in Table 1.

RADIOMETRY

e) SLI shall produce and distribute calibrated digital images providing data that transform linearly to top-of-the-atmosphere spectral reflectance for each of the spectral bands 1-9 as listed in Table 1;

f) SLI shall relate image data, after calibration, to at-aperture spectral radiance and reflectance with an absolute uncertainty of less than 5% and 3%, 1-sigma, respectively, for each of the spectral bands 1-9 as listed in Table 1;

g) SLI shall produce and distribute calibrated digital images providing data that transform linearly to at-aperture spectral radiance for thermal bands 10 and 11 (Table 1);

h) SLI shall relate image data, after calibration, to at-aperture spectral radiance with an absolute radiometric uncertainty of less than 2%, 1-sigma from 240K to 360K, for each of the thermal bands 10 and 11 as listed in Tables 1 and 3;

GEOMETRY

i) SLI shall meet reflective and thermal radiometric performance detailed in Tables 2 and 3;

j) The SLI project shall generate and distribute orthorectified data products (L1T) for all spectral bands listed in Table 1;

k) SLI shall provide reflective Level 1T data products with a geometric pixel uncertainty of less than 5 meters and band-to-band co-registration of 4.5 m circular error at the 90% confidence level;

l) SLI shall provide thermal Level 1T data products with a thermal band-to-thermal band co-registration accuracy of 10 meters in the along- and cross-track directions at the 90% confidence level;

m) SLI shall provide Level 1T data products with corresponding pixels from the two thermal bands and the nine reflective bands that are co-registered with an uncertainty of 20 meters or less in the flight and cross-track directions at the 90% confidence level;

DATA ACCESS

n) The SLI project shall allow the Landsat user community and the general public to search the SLI data archive and obtain data products on a non-discriminatory basis;

o) The SLI project shall document and publicly release all algorithms, telemetry, and metadata used to create SLI data products.

Table 1. Spectral bands and spatial resolution requirements.

# Band Minimum

Lower Band Edge (nm)

Maximum Upper Band Edge (nm)

Center Wavelength nm)

Maximum Spatial

Resolution at Nadir (m)

1 Coastal/Aerosol 433 453 443 30 2 Blue 450 515 482 30 3 Green 525 600 562 30 4 Red 630 680 655 30

5 NIR 845 885 865 30

6 SWIR 1 1560 1660 1610 30

7 SWIR 2 2100 2300 2200 30

8 Panchromatic 500 680 590 30 9 Cirrus 1360 1390 1375 30 10 Thermal 10300 11300 10800 100 11 Thermal 11500 12500 12000 100

Table 2. SLI expected on-orbit signal-to-noise (SNR) performance.

# Band SNR Typical

Radiance (W / m2 sr µm)

Saturation Radiance

(W / m2 sr µm) 1 Coastal/Aerosol 245 40 190 2 Blue 400 40 190 3 Green 330 30 194 4 Red 235 22 150

5 NIR 215 14 150

6 SWIR 1 280 4.0 32

7 SWIR 2 335 1.7 11

8 Panchromatic 170 23 156 9 Cirrus 155 6.0 N/A

Table 3. Expected Noise Equivalent Delta-Temperature (NE∆T) for SLI thermal instrument on-orbit performance in terms of degree Kelvin (K).

Source Temperature

(K)

Band 10 (K)

Band 11 (K)

240 0.069 0.096 270 0.054 0.076 300 0.047 0.066 320 0.045 0.063 360 0.044 0.059