First Flight of NASA

1
First Flight of NASAs Coastal and Ocean Airborne
Science Testbed (COAST)
L. Guild1, J. Dungan1, M. Edwards1, P. Russell1,
J. Morrow2, S. Hooker3, J. Myers4, R. Kudela5, S.
Dunagan1, M. Soulage6, J. Livingston7, R.
Johnson1, T. Ellis4, N. Clinton4, R. Dominguez4,
B. Lobitz8, K. Martin1, E. Fraim4, P. Zell1,
R.Berthold1, C. Smith1, K. Vassigh1, A. Demo1,
W. Gore1, and J. Torres9
1NASA Ames Research Center, Moffett Field, CA
94035 2Biospherical Instruments Inc., San Diego,
CA 92110 3NASA Goddard Space Flight Center, MD
20771 4Univ. of California, Santa Cruz/NASA,
Moffett Field, CA 94035 5Univ. of California,
Santa Cruz, Santa Cruz, CA, 95064 6Universities
Space Research Association/NASA Ames Research
Center, Moffett Field, CA, 94035 7SRI
International/NASA Ames Research Center, Moffett
Field, CA 94035 8Univ. Corporation at Monterey
Bay/NASA Ames Research Center, Moffett Field, CA
94035 9NASA Postdoctoral Program/NASA Ames
Research Center, Moffett Field, CA 94035
Abstract
Payload
Imaging Spectrometer
Science Mission October 2011
The NASA Coastal and Ocean Airborne Science
Testbed (COAST) project advances coastal
ecosystems research and ocean color calibration
and validation capability by providing a unique
airborne payload optimized for remote sensing in
the optically complex coastal zone. The COAST
instrument suite combines a customized imaging
spectrometer, sunphotometer system, and a new
bio-optical radiometer package to obtain
ocean/coastal/atmosphere data simultaneously in
flight for the first time. The imaging
spectrometer (Headwall) is optimized in the blue
region of the spectrum to emphasize remote
sensing of marine and freshwater ecosystems.
Simultaneous measurements supporting empirical
atmospheric correction of image data is
accomplished using the Ames Airborne Tracking
Sunphotometer (AATS-14). Coastal Airborne In situ
Radiometers (C-AIR, Biospherical Instruments,
Inc.), developed for COAST for airborne campaigns
from field-deployed microradiometer
instrumentation, will provide measurements of
apparent optical properties at the land/ocean
boundary including optically shallow aquatic
ecosystems. Results of the October 2011 Monterey
Bay COAST mission include preliminary data on
coastal ocean color products, coincident spatial
and temporal data on aerosol optical depth and
water vapor column content, as well as derived
exact water-leaving radiances.
N
Above True color composite of Headwall imaging
spectrometer raw data showing 450 nm (red), 550
(green), and 680 (blue). Pixel resolution is 4
m.Right Enhanced raw data shows algal bloom
in red.
Flight path for October 28, 2011.
Right Reflectance examples for points within
the red tide (red lines) and outside of the red
tide (blue lines).

• Ship-based Measurements
• Underway T, S, Fluorescence
• At each station (2-3 stations per day)
• Size fractionated chlorophyll, flow cytometry
  counts
• CDOM, absorption spectra, nutrients
• Sunphotometer spectra
• Satlantic HyperPro cast, C-OPS cast
• Water-leaving radiance, profile data
• Backscatter/ac-S casts
• ASD surface reflectance

AATS
COAST Mission
Preliminary Data
HyperPro II (Ship-based)
Left Aerosol optical depths (AOD) calculated
from AATS-14 measurements for horizontal
transects on 28 Oct. at altitudes 0.024 km ASL
(top left) and 1.877 km ASL (bottom left). The
AATS-14 channel center wavelengths (in µm) are
given in the legend. Right Corresponding mean
AOD spectra (symbols) and log(AOD) vs.
log(wavelength) quadratic fits (dashed lines)
calculated for the total column above the
aircraft for the low (blue) and high (red) flight
legs, and for the layer (green) bounded by the
two altitudes.
Ames Airborne Tracking Sunphotometer (AATS)

• Measures
• Solar direct-beam transmission (T) at 14
  wavelengths, 353-2139 nm
• Data products
• Aerosol optical depth (AOD) at 13 l, 353-2139 nm
• Water vapor column content using T(940 nm)
• Aerosol extinction,
• 340-2139 nm
• Water vapor density

Monterey Bay has both open ocean and optically
complex water masses, so the full dynamic range
of the sensor suites and protocols being used in
the field can be evaluated. The mission
consisted of flying the imaging spectrometer,
together with the AATS and C-AIR on the CIRPAS
Twin Otter, over an instrumented surface to
evaluate the sensor suite. The AATS provides a
simultaneous empirical characterization of the
atmospheric column (AOD and water vapor) that
will be used for atmospheric correction. During
flights, we obtained MODIS Aqua and Terra, HICO,
and MERIS data corresponding to contemporaneous
deployment of the ship-based measurements from
the R/V John Martin (Moss Landing Marine Lab).
Satellite observations will be used to compare
accuracy of radiance retrievals and derived
products versus the Headwall imaging
spectrometer, C-AIR, and the in situ measurements.
HyperPro II remote sensing reflectance in red
tide site.
HyperPro II profile at M0 site
C-AIR
Vertical profiles of columnar water vapor (left),
spectral AOD (middle), and spectral aerosol
extinction (right) calculated from AATS-14
measurements acquired during a spiral descent
over Monterey Bay on 28 October.
Science Traceability Matrix
Coastal Airborne In-situ Radiometers (C-AIR)
Scientific Outcomes

• A flight-tested instrument suite suitable for
  cal/val activities for future satellite missions,
  as well as currently operating and developing
  missions.
• Advanced payload capabilities for airborne
  carrier platforms including UASs.
• A multi-sensor ocean/atmosphere data set
  available for improved atmospheric calibration
  and in-water algorithms.
• Methodologies for empirical atmospheric
  correction developed for future airborne imagers
  of this type (e.g., NASA PRISM) when they come
  online.
• Methods to address the biological properties of
  important coastal zone ecosystems.
• Enabling technology for a broad range of
  research activities in the coastal zone to
  support the scientific communitys research goals
  and objectives.
• Funding NASA HOPE, Science Mission Directorate,
  Office of Chief Engineer, and SMD/Earth Science
  Division

Raw data at 555 nm for solar irradiance (Es), sky
radiance (Li) reaching the sea surface, and total
radiance (Lt) above the sea surface. UTC is 7hrs
from local time.
C-AIR measurements of the downward irradiance
(Es), sky radiance away from the sun (Li) and
total surface radiance (Lt) for each 30 second
segment of all flight lines showed small
vari-ances, but were mostly spectrally similar.
Shown are spectra from 30 second segments
processed for glint avoidance by PROSIT along
flight line 7, 10-28-11, 6000 ft.
Acknowledgements
Naval Postgraduate School Center for
Interdisciplinary Remotely Piloted Aircraft
Systems (CIRPAS) Twin Otter Team.UC Santa Cruz
and Moss Landing RV John Martin field team.UC
Davis Spectral Measurements Team Mui Lay,
George Scheer, and Susan Ustin.
http//geo.arc.nasa.gov/coast/coast_index.html