James Acker1, Greg Leptoukh1, Steve Kempler1, Watson Gregg2, Steve Berrick1,

1
Real Data and Rapid Results
James Acker1, Greg Leptoukh1, Steve Kempler1,
Watson Gregg2, Steve Berrick1, Tong Zhu1, Zhong
Liu1, Hualan Rui1, Suhung Shen1 1 NASA Goddard
Earth Sciences (GES) Data Information Services
Center (DISC) / Distributed Active Archive Center
(DAAC) Code 902, NASA Goddard Space Flight
Center Greenbelt, Maryland 20771 USA 2 GSFC
Laboratory for Hydrospheric Processes, Code
970 http//daac.gsfc.nasa.gov/ FOR MORE
INFORMATION acker_at_daac.gsfc.nasa.gov The Ocean
Color Time-Series Project, including Giovanni
development, is supported by NASA through REASoN
CAN 42-OES-01.
Ocean Color Data Analysis with Giovanni
(GES DISC Interactive Online Visualization and
ANalysis Infrastructure)
Summary
Laboratory for Ocean Color Users (LOCUS)
Tutorials Intriguing Observations
The NASA Goddard Earth Sciences Data and
Information Services Center (GES DISC) has taken
a major step addressing the challenge of using
archived Earth Observing System (EOS) data for
regional or global studies by developing an
infrastructure with a World Wide Web interface
which allows online, interactive, data analysis
the GES DISC Interactive Online Visualization and
ANalysis Infrastructure, or "Giovanni." Giovanni
provides a data analysis environment that is
largely independent of underlying data file
format. The Ocean Color Time-Series Project has
created an initial implementation of Giovanni
using monthly Standard Mapped Image (SMI) data
products from the Sea-viewing Wide Field-of-view
Sensor (SeaWiFS) mission and Moderate Resolution
Imaging Spectroradiometer (MODIS-Aqua). The first
phase of this project includes tutorials
demonstrating the use of Giovanni and
collaborative assistance in the development of
research projects using SeaWiFS, MODIS-Aqua, and
Ocean Color Time-Series Project data in the
online Laboratory for Ocean Color Users (LOCUS).
Synergy of Giovanni with high-quality ocean
color data provides users with the ability to
investigate a variety of important oceanic
phenomena, such as coastal primary productivity
related to pelagic fisheries seasonal patterns
and interannual variability interdependence of
atmospheric dust aerosols and harmful algal
blooms and the potential effects of climate
change on oceanic productivity.
Influence of El Niño on the Gulf of Panama
Seasonal Productivity Cycle
The biological dynamics of the Gulf of Panama are
dominated by winter wind-mixing events.
Atmospheric pressure differences on the Pacific
and Caribbean sides of the Isthmus of Panama
cause high wind speed events through the Gaillard
Cut (Panama Canal Zone). These winds mix
nutrients from deeper waters to the surface,
resulting in increased phytoplankton productivity
and higher chlorophyll concentrations. This
tutorial investigated the influence of El Niño/La
Niña events on the phytoplankton productivity of
the Gulf of Panama. The expected suppression of
productivity during the strong 1997-1998 El Niño
was observed. The tutorial also observed
anomalously higher chlorophyll concentrations in
autumn 2001, preceding the occurrence of a
moderate El Niño in 2002-2003. Further
investigation is required to determine if this
observation is an El Niño precursor.
Average chlorophyll concentrations over the
SeaWiFS mission period show the characteristic
seasonal pattern, and the influence of El Niño.
Latitude vs. time plot displaying reduced
chlorophyll during 1997-1998 El Niño, and
anomalous increased productivity during autumn
2001.
Wind-mixing events during winter enhance
phytoplankton productivity in the Gulf of Panama.
Seasonal Patterns and Mysteries in the Red Sea
The Red Sea is one of the lowest-productivity
bodies of water in the world, due primarily to
low nutrient concentrations. No major rivers
enter the Red Sea. The clarity and warmth of the
Red Sea waters, and its remoteness, make it home
to many of the worlds most pristine coral reefs.
This tutorial investigated seasonal cycles in
the Red Sea. SeaWiFS ocean color data indicated
that the northern Red Sea has a brief spring
bloom pattern, with slightly elevated
chlorophyll concentrations that are still quite
low. The southern Red Sea has a distinctly
different seasonal pattern that is linked to the
Arabian Sea monsoon. Giovanni data analysis in
the northern Red Sea indicated a small,
mysterious feature of elevated chlorophyll
concentrations in the winter, spring, and fall,
which was absent in the summer. Examination of
maps and descriptions of this area indicated that
the feature was in the location of the large
Mirear Island reef complex. The seasonality of
the elevated chlorophyll concentrations supports
a hypothesis that the higher chlorophyll
concentrations are due to wind transport of
chlorophyll-rich detritus from this reef.
DATA AVAILABLE

• SeaWiFS monthly global 9-km product
• MODIS-Aqua monthly global 9-km product
• SeaWiFS SMI Products chlorophyll a
  concentration, K(490), nLw(555), Angstrom
  coefficient
• 510-865nm, t(865). MODIS products use closest
  equivalent wavelength.

Landsat image of the Mirear Island reef complex
(obtained from the Millenium Coral Reef Project
image library). Higher chlorophyll
concentrations shown in the figure at left occur
offshore of this reef complex.
Annual chlorophyll concentrations in 2001 on the
Red Sea coast show the location of the unusual
feature (dynamic color scale is used here).
Latitude vs. time plot for the year 2001, showing
the northern Red Sea spring bloom and an unusual
ocean color feature observed in winter, spring,
and autumn.
Average chlorophyll concentrations in the Red Sea
in the year 2001.
The REASoN for Giovanni
The Goddard Earth Sciences Data and Information
Services Center (GES DISC) created Giovanni the
GES DISC Interactive Online Visualization and
ANalysis Infrastructure as a prototype data
analysis tool for the multi-decadal ocean color
time-series products that are currently being
created by the Ocean Color Time-Series Project, a
Research, Education, and Applications Solution
Network (REASoN) project. Giovanni facilitates
the use of these data products by providing data
analysis capabilities without the necessity for
ordering and acquiring large data volumes or
extensive sets of data files. Tools like
Giovanni alter the role of a data archive from
that of a data provider to a more interactive
role as an intermediary in the research use of
data products contained in the archive.
Giovannis initial implementation uses Level 3
Standard Mapped Image (SMI) products from the
Sea-viewing Wide Field-of-view Sensor (SeaWiFS)
mission and Moderate Resolution Imaging
Spectroradiometer (MODIS) Level 3 SMI products
created by the Ocean Color Data Processing System
(OCDPS) for MODIS-Aqua data. The Ocean Color
Time-Series Project will create a multi-decade
ocean color time-series with the addition of data
from the Coastal Zone Color Scanner (CZCS) and
the Ocean Color and Temperature Scanner (OCTS) to
the SeaWiFS and MODIS data sets, and will create
a framework allowing the eventual addition of
other ocean color data sets, such as new data
from the Visible/Infrared Imaging Radiometer
Suite (VIIRS). Giovanni users select geophysical
parameters and the geographical region and time
period of interest. The system rapidly generates
graphical or ASCII numerical data output.
Currently available output options are Area plot
(averaged or accumulated over any available data
period for any rectangular area) Time plot (time
series averaged over any rectangular area)
Hovmöller plots (image view of any longitude-time
and latitude-time cross sections) ASCII output
for all plot types and area plot animations.
Future plans include correlation plots, output
formats compatible with Geographical Information
Systems (GIS), and higher temporal resolution
data. The Ocean Color Time-Series Web site
provides access to Giovanni, explanation of the
goals of the project, progress reports, and other
relevant information. The Web site hosts the
Laboratory for Ocean Color USers (LOCUS), which
provides (or will provide in the future)
demonstrations of Giovanni applications guidance
and assistance for research investigations and
projects and examples of ocean color research
efforts which have utilized Giovanni and the
time-series data products. The first activity
within LOCUS was the creation of three research
tutorials. These tutorials examined familiar
settings in which the underlying biological
dynamics were relatively well-known. However,
in the course of creating the tutorials, Giovanni
allowed the observation of unexpected features in
the data, showing that Giovanni enables
open-ended discovery-based research. Because
the use of Giovanni is highly intuitive and
remarkably simple, Giovanni enables scientific
investigation and instruction at the entry
level undergraduates and even high school
students. Giovanni enhancements planned for the
near-future will make it even more useful to a
broad spectrum of the oceanographic research
community. These enhancements include
correlation plots error analysis capability
output formats compatible with Geographical
Information Systems (GIS) more image format
options and higher temporal resolution data.
Giovanni Session Demonstration Seasonal
Productivity in the southeast Caribbean Sea
This demonstration was created solely for this
poster and had not been conducted previously.
Area plot of chlorophyll a concentrations during
the low productivity phase, February 2002.
Higher chlorophyll concentrations are observed in
the coastal region of Venezuela, and
significantly lower concentrations in the
Caribbean Sea, especially around the Lesser
Antilles.
Giovanni Home Page
Area plot of chlorophyll a concentrationsduring
the high productivity phase, July 2002. The
influence of nutrients in the Orinoco River
outflow is clearly seen in this monthly area
plot. Also note in the southeastern corner of
the region another area of increased
productivity, likely due to increased freshwater
flow from the Amazon River.
GES DISC THE BRIDGE BETWEEN DATA AND SCIENCE
FOCUS ON RESULTS
ADD VALUE TO RESULTS
USE GIOVANNI FOR FURTHER ANALYSIS
PUBLISH
BRING THE EARTH INTO FOCUS
Remote sensing data and data products at no cost
Modular algorithm integration for high-volume
processing
Complex data interpretations and statistical
analyses
Focus on analysis without having to download data