Simultaneous measurements of aerosol optical depth, size
distribution and the incoming solar radiation flux with four independent
gimbal mounted spectral and broad band radiometers were carried out over
the coastal Indian region, the Arabian sea and the Indian Ocean during a
cruise conducted in Jan-Feb. 1996. Columnar aerosol optical depth in the
visible wavelength region was found to be in the range of 0.2 to 0.5 over
the Arabian Sea and was 0.1 and below over the equatorial Indian ocean
region. Aerosol mass concentration decreased from a high of about 80
micrograms/m3 near the coast to a low of few micrograms/m3 over the
interior ocean region. The sub micron size (<0.1 microns) particles showed
more than an order of magnitude increase in the number concentration near
the coast than that over the interior ocean. This large increase in the
number of small particles seen towards the coast was also consistent with
the corresponding large increase in the sun photometer derived Angstrom
exponent which increased from 0.2 over the Indian ocean to about 1.4 near
The radiative forcing from the aerosol was obtained for the direct
solar flux and for the global (direct + diffuse) solar flux separately in
the UV, visible and near IR spectral regions. We show that the global and
diffuse fluxes when normalized with "mu" (cosine of the solar zenith angle)
vary almost linearly with columnar aerosol optical depth normalized with
"mu," within the aerosol optical depth ranges considered in this study.
The variation of the normalized fluxes in response to the variations in the
normalized columnar aerosol optical depth are used to obtain the radiative
forcing. The experimental results show that the direct visible (<780 nm )
solar flux decreases by about 42 W.m -2 and the diffuse sky radiation
increases by about 30 W.m -2 with every 0.1 increase in columnar aerosol
optical depth for midday solar condition (solar zenith angle within 60
degrees). The average reduction in the global flux for the visible
component is found to be about 14 W.m -2 with every 0.1 increase in
columnar aerosol optical depth. For the same extinction optical depth, the
radiative forcing (direct + diffuse) of the coastal aerosols is larger than
the open ocean aerosol forcing, by a factor of 2 or larger.
The data when taken together, reveal a strong latitudinal gradient
in the aerosol mass, number concentration, optical depth and radiative
forcing, decreasing from the Arabian Sea to the equatorial Indian Ocean.
The magnitude of the gradient and the radiative forcing indicate the
significance of this region to the global radiative forcing.
INDOEX CRUISE #120 COMPLETED IN JANUARY
--Contributed by Bill Conant, C4/SIO--
On January 31, 1997, the R/V Sagar Kanya returned to port in Goa, India
after a successful 5 week cruise in the Indian Ocean. This third
pre-INDOEX cruise (#120) was the most intensive to date, providin
g a wealth of information on physical, chemical, and optical properties of aerosols
south from the Arabian Sea, through the Inter-tropical Convergence Zone, to
the South Indian Ocean. The multi-disciplinary effort included US groups
from SIO/UCSD, the National Center for Atmospheric Research, the University
of Alaska, and North Carolina State University; and Indian groups from
National Physical Laboratory, the Physical Research Laboratory, the
National Institute of Oceanography, and SPL/Vikram Sarabhai Space Centre.
OTHER INDOEX CRUISE NEWS
The next INDOEX cruise sets sail from February 12-March 31, 1998. The R/V
Sagar Kanya will depart and return to Mormugao, and make ports of call in
Male, Maldives (2 days) and Port Louis, Mauritius (3 days). Dr. L.V.G. Rao
of the National Institute of Oceanography, Goa, will coordinate this cruise.
INDOEX DATABASE RELEASE
--Contribution by Suzanne Rupert, SIO--
The INDOEX database within the C4 Integrated Data System (CIDS) is now
available for your use. This database contains data gathered prior to 05
February 1996 during pre-INDOEX cruises. Thanks go to all Principal
Investigators involved for granting permission to release their data to the
general public at this time. The AVHRR GAC and Krishnamurti Model Analyses
Data have not yet been placed within the database due to disk space
limitations. These data will be made available with the next database
The database is accessible through the world wid /www- http://www-c4.ucsd.edu/~cids/
Information pertaining to the details of the INDOEX Proposal may be obtained at: http://www-indoex.ucsd.edu
While this release is being made available to the public, all users should
contact the Principal Investigator for the dataset they are using for
clarification and quality control related issues.
The CIDS 0.4.1 Database Engine is an effective means of extracting and
spatio-temporally collocating large sets of data obtained from diverse
platforms and instruments. In an effort to ensure user satisfaction we are
constantly working to improve data access times and increase database
engine flexibility. Please note this release replaces the CIDS 0.4
release. CIDS 0.4.1 was created to accommodate modifications in the INDOEX
database attribute list. If you have any questions regarding the database,
please direct them to email@example.com.
** NEWS FLASH ** NEW C4 PUBLICATION **
Congratulations to Dr. C.P. Weaver and Prof. V. Ramanthan whose article,
"Relationships Between Large-Scale Vertical Velocity, Static Stability and
Cloud Radiative Forcing Over Northern Hemisphere Extra-Tropical Oceans,"
will be published in the Journal of Climate.
(Editor's Note to C4 Principal Investigators: Please submit notice of your
recent publications to include in this newsletter. Thank you.)
The Center for Atmospheric Sciences, C4 and Oregon State University
presented Dr. Norman G. Loeb, OSU, "Cloud Properties Retrieval from
Satellite Measurements: Limitations of the Plane Parallel Model Approach,
" on February 10.
The Center for Atmospheric Sciences presented Dr. Mark G. Lawrence,
Max-Planck Institute for Chemistry, Mainz, Germany, "Atmospheric Chemistry
Studies with MATCH (Model of Atmospheric Transport and Chemistry)," on
The Center for Atmospheric Sciences presented Dr. Hope Michelsen, Harvard
University, "Chemical and Dynamical Processes Controlling Stratospheric
Ozone: Understanding Observed Trends and Predicting the Future," on March
The Center for Atmospheric Sciences presented Dr. Kristie Boering, Harvard
University, "Stratospheric Mean Ages and Transport Rates from In-situ
Measurements of CO2 and N2O: Improving Predictions of Natural and
Anthropogenic Perturbations to Stratospheric Ozone," on April 7.
The Center for Atmospheric Sciences presented Dr. Jeffrey Kiehl, NCAR, "The
Role of Clouds in Modeling the Climate System," on April 14.
The Center for Atmospheric Sciences presented Dr. Francisco Valero,
CAS/SIO-UCSD, "The Absorption of Solar and Infrared Radiation by the
Atmosphere: Excess Absorption and Super Greenhouse Effect," on April 17.
The Center for Atmospheric Sciences presented Duane Waliser, SUNY Stony
Brook, "The Influence of Coupled Sea Surface Temperatures on the
Madden-Julian Oscillation: A Model Perturbation Experiment," on April 21.
RECENT INDOEX VISITORS
* Prof. Paul Crutzen, Max-Planck Institute for Chemistry, February 18-March 5.
* Dr. Jos Lelieveld, Institute for Marine and Atmospheric Research Utrecht,
* Dr. Sethu Raman, North Carolina State University, March 10.
* Dr. A. Jayaraman, Physical Research Laboratory, Ahmedabad, March 25-April 20.
* Drs. Jochen Landgraff and Thomas Trautmann, Max-Planck Institute for
Chemistry, May 21-June 16.
* Dr. Alexander Marshak, NASA Goddard Space Flight Center, June 6-11.
* Dr. Bhaskar Jha, Department of Meteorology, Florida State University,
NEW C4 POST-DOC
Dr. Jens Meywerk, a former doctoral student with Prof. Grassl of the
University of Hamburg, will join C4 as a post-doctoral physicist in June.
INTERNATIONAL DISCUSSIONS ON ENVIRONMENTAL EDUCATION
Dr. Monica Hamolsky, Director of Teachers and Outreach at the Stephen Birch
Aquarium, attended "Environmental Education for the Millennium," a
NATO-funded conference at the Pasteur Institute in Paris. Participants
studied strategies for promoting environmental education across Europe.
She also attended a meeting of the Alliance for Global Sustainability
(AGS), an international partnership between the Swiss Federal Institutes of
Technology, the Massachusetts Institute of Technology, and the University
of Tokyo in Zurich. AGS conducts research to ameliorate anthropogenic
effects on climatological and ecological systems.
BRIGHT FUTURE FOR "FORECASTING THE FUTURE"
"Forecasting the Future: Exploring Evidence for Global Climate Change," a
curriculum and classroom activity guide for grades 5-12, has been used in
several teacher workshops, referenced in national databases, and reviewed
in several newsletters. It is also under review by several curriculum
development groups in states across the country.
* Carroll A. Hood, Director, US Global Change Research Information
Office/Consortium for International Earth Science Information Network,
reported that "Forecasting the Future" will be indexed and included in the
Earth Education Site data base.
* Douglas M. Messier, National Science Teachers' Association, noted that
the spring issue of "The Green Journal," a teacher's journal on the
environment in Canada includes a positive review of "Forecasting the
Future." This journal reaches educators interested in the topic across
* Carl Bollwinkel, University of Northern Iowa, wrote, "Thanks for sending
the book on climate change. I had a chance to skim it and share it with my
teaching team. We are ordering additional copies." Dr. Bollwinkel
contributes to a state-wide effort to integrate global change into Iowa's
Julie des Rosiers