Light and Agenda

• and Water – How light propagates through the atmosphere and , and back to sensor – Constituents of the water column and their inherent optical properties • Fundamentals of Remote Sensing • Aquatic Remote Sensing Data Products and Their Uses • Accessing NASA Satellite Imagery • NASA Satellite Data Processing Tools

Phytoplankton Bloom in the Arabian Credit: N. Kuring, http://earthobservatory.nasa.gov/IOTD/view.php?id=85718

National Aeronautics and Space Administration Applied Remote Sensing Training Program 7 First, an Aquatic Optics Primer… The

National Aeronautics and Space Administration Applied Remote Sensing Training Program 8 How Light Interacts with Water Defining Remote Sensing Reflectance (Rrs) – or ‘ ’

Inherent Optical Properties a = absorption by… phytoplankton (ph) non-algal particles (nap) colored dissolved organic matter (CDOM) aph a w water (w) aCDOM anap b = in forward (f) and backward (b) bb directions

Fluorescence bf

National Aeronautics and Space Administration Applied Remote Sensing Training Program 9 How Light Interacts with Water Defining Remote Sensing Reflectance (Rrs) – or ‘’

Inherent Optical Properties

Rrs a = absorption b = scattering Ed Lw

Lu Apparent Optical Properties aph aw Lw = water leaving radiance a a CDOM Lu = radiance nap b b Ed = irradiance Rrs = remote sensing (rs) reflectance

Fluorescence bf

National Aeronautics and Space Administration Applied Remote Sensing Training Program 10 Inherent Optical Properties (IOPs) and the ‘Color’ of Water

Light absorption (a) by photoplankton (ph), non-algal particles (nap), water (w), and colored dissolved organic matter (CDOM)

a = aph + anap + aCDOM + aw

Light scattering (b) by particles in forward (bf) and backward (bb) direction

b = bf + bb

National Aeronautics and Space Administration Applied Remote Sensing Training Program 11 Inherent Optical Properties (IOPs) and the ‘Color’ of Water

chlorophyll

water

CDOM

nap/ sediments

National Aeronautics and Space Administration Applied Remote Sensing Training Program 12 Inherent Optical Properties (IOPs) and the ‘Color’ of Water

Visible Near IR chlorophyll ) 1 − r

s 0.025 sediments 0.02 water ) 1 - 0.015 (sr reflectance ( g n i s

Rrs 0.01 CDOM n e s

− CDOM e t 0.005 water o

m chlorophyll e

nap/ R 0 sediments 400 500 600 700 800 900 Wavelength (nm) National Aeronautics and Space Administration Applied Remote Sensing Training Program 13 Inherent Optical Properties (IOPs) and the ‘Color’ of Water

• The typical has color- Visible Near IR detecting receptors that sense light ) 1

at: − r

s 0.025 – 420-440 nm ‘’ – 534-555 nm ‘’ 0.02 – 564-580 nm ‘’ ) 1 - 0.015 (sr reflectance (

• Water with high chlorophyll content g n i s

Rrs 0.01 looks green because it reflects n e strongly in the green part of the s − e spectrum t 0.005 o

m chlorophyll e R 0 400 500 600 700 800 900 Wavelength (nm) National Aeronautics and Space Administration Applied Remote Sensing Training Program 14