Purpose of this amendment is to respond to questions received in reference to the specifications. 

1) The term "Hyperspctral" refers to a sensor with the ability to measure simultaneously spectral information from multiple spatial locations (see our web site, under PRODUCTS and the HyperScan). As such, the subject solicitation does not talk about the Field of View(FOV) desired for the instrument. Also, "how many spatial positions are needed?" The answer can be from 1 to hundreds or thousands. If theanswer is "one" can this be defined as a "spectrometer" rather than a "hyperspectral"?

Reply: Field of View (FOV):The above ocean surface water radiance sensor and sky radiance sensor shall have 3 degrees FOV. A larger FOV may cause problems with integrating over larger ranges of variability (see NASA/TM-2000-209966 Ocean Optics Protocols for Satellite Ocean Color Sensor Validation).

Spatial positions:The required instrument shall not produce spatial/pixel composite images. The required instrument shall produce a measurement at a single specified latitude and longitude location.

 2)Is "water radiance" referring to the reflected radiance off the water as seen by the downlooking instrument?

Reply: Water radiance is defined here as radiance emanating from the sea surface at a zenith and azimuth angle. Water radiance is measured by the downlooking instrument.

3) While operating on a boat / mooring / and airborne -- can I assume that the Hyperspectral sensor is always down-looking? Does the sky radiance cover the full hemisphere or is this a directional measurements? Should the sun be blocked from sky radiance?

Reply: The above ocean surface water radiance sensor shall measure L(surface) and is always down-looking. The sky radiance sensor shall measure L(sky) looking upward at a specified angle (see Chpt 10 NASA/TM 2000-209966). The sun should not be blocked from sky radiance.

 4) The downwelling irradiance -- is that again a cosine response to thetotal downwelling energy?

Reply:  Downwelling irradiance (Es) is the incident spectral irradiance measured above the sea surface with a cosine sensor (see Chpt 10 NASA/TM 2000-209966).

 No change in response date, May 21,2009.