SAGE III (Stratospheric Aerosol and Gas Experiment) Project Guide Document
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SAGE III (Stratospheric Aerosol and Gas Experiment) Project Guide Document |
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The SAGE III instrument utilizes the self-calibrating solar occultation technique to measure profiles of aerosols, clouds, ozone (O3), nitrogen dioxide (NO2), and water vapor (H2O), identified as critical in the U.S. National Plan for Stratospheric Monitoring, and utilizes lunar occultation observations to monitor the key nighttime species nitrogen trioxide (NO3) and chlorine dioxide (OClO).
SAGE III is a natural and improved extension of the very successful SAM II, SAGE I, and SAGE II experiments. The solar occultation (SOC), or Earth-limb extinction technique employed by these experiments is inherently a well-posed, well-behaved inversion problem, is self-calibrating, and has demonstrated high vertical resolution and high signal-to-noise and, therefore, possesses excellent accuracy.
SAGE III (Stratospheric Aerosol and Gas Experiment)
Since the 1950's, it has become increasingly clear that human activities are modifying the composition of the atmosphere on a global scale. As the result of industrialization, the concentration of carbon dioxide has increased by about 20 0uring this period.
More recently, the stratospheric concentrations of chemically-active gases containing chlorine, bromine, and fluorine have dramatically increased (see the World Climate Research Program). These trends have created issues of global interest including global warming and declining levels of ozone (both globally and in the ozone "hole" in the Antarctic).It has become increasingly clear, however, that these processes do not occur independently of one another and can only be understood in the context of a global system.
As a result, in 1991 NASA initiated a comprehensive program to understand the Earth's atmosphere, oceans, land, and cryosphere (ice and snow) as a single, complex, interactive system. NASA's Earth Observing System (EOS) consists of a series of spaceborne instruments to monitor crucial components of the Earth system, an advanced data handling system, and teams of scientists who will evaluate on-going climate change and predict future changes. Ultimately, EOS will produce scientifically sound recommendations for environmental policy to national and international bodies to mitigate or prepare for these changes.
SAGE III's role in the EOS program is to provide global, long-term measurements of key components of the Earth's atmosphere. The most important of these are the vertical distribution of aerosols and ozone from the upper troposphere through the stratosphere. In addition, SAGE III also provides unique measurements of temperature in the stratosphere and mesosphere and profiles of trace gases such as water vapor and nitrogen dioxide that play significant roles in atmospheric radiative and chemical processes. The SAGE III Science Team functions in a dual role where they ensure the data quality and interpret the SAGE III data in the broader context of global change.
The specific measurement objectives of SAGE III are to provide 1 km vertical resolution profiles of: aerosols and clouds at seven wavelengths from the mid-troposphere into the stratosphere and where appropriate, the mesosphere; O3 from the mid-troposphere to 85 km; H2O from the planetary boundary layer to 50 km; NO2 from the tropopause to 45 km; NO3 from 20 to 55 km; OClO from 15 to 25 km; and, O2 from the mid-troposphere to 70 km. These measurements will provide important data that address the major objectives of EOS including the impact of these species on global climate change.
Earth Sciences
Atmospheric Sciences
The Russian Space Agency's Meteor-3M will be placed in a sun synchronous orbit that yields solar measurement opportunities between 50 and 80 degrees North and 30 and 50 degrees South. The high northern latitude coverage will provide insight into the processes leading to ozone depletion during boreal winter and provide coverage that complements the mid and low latitude coverage provided by SAGE II and other SAGE III missions.
This data will be in HDF (Hierarchical Data Format).
Data will be made available to the user via 8mm tape or by FTP (see Data Access section below).
There is no proprietary status for the data sets currently on-line at the Langley DAAC.
The SAGE III data will be accessible by contacting the NASA Langley DAAC and through the Warehouse Inventory Search Tool (WIST).
The EOS Data Gateway system will serve as the main search and order service for the EOSDIS Core System (ECS) which is being built to accommodate the tremendous amount of data expected from the new series of EOS instruments.
The EOS Gateway allows users to search science data holdings, retrieve high-level descriptions of data sets and detailed descriptions of the data inventory, view browse images, and place orders for data products.
Search methods are available to aid the user in obtaining the desired data. A general search is made by specifying geographic areas of interest along with either geophysical parameter, dataset name, or sensor name. Three different search types provide increasingly detailed information about the science data available through the system. A directory search provides summary information about EOSDIS data sets. This type of search accesses the Global Change Master Directory (GCMD), a multidisciplinary database of information about Earth science data. A guide search provides detailed descriptions about data sets, data sources, instruments, projects, and data centers; it may include algorithm descriptions and calibration information. The inventory search gives descriptions of specific observations or collections of observations of data (granules) that are available from a data center.
The Gateway system includes a coverage map which is a graphical representation of the geographic coverage of selected data observations (data granules).
A browse function is also included which allows the user to view data (possibly reduced in resolution) as an aid for selecting many of the products available from the data centers. Such data may be viewed in the EOS Data Gateway interface or retrieved via File Transfer Protocol (FTP).
The order function allows the user to select the desired data processing options and media, and allows the user to specify contact, billing, and shipping addresses.
To access the Data Gateway, a user is required to provide a simple, one-time registration to access data at the DAACs and a valid login and password is then sent to the user.
Langley DAAC User and Data Services Office
NASA Langley Research Center
Currently, there is no cost associated with this data.
Dr. William P. Chu
Project Scientist
NASA Langley Research Center
The requested form of acknowledgment for any publication in which this data are used is:
"These data were obtained from the NASA Langley Research Center EOSDIS Distributed Active Archive Center."
The Langley DAAC requests two reprints of any published papers or reports which cite the use of data that the Langley DAAC have distributed. This will help the DAAC to determine the use of data distributed, which is helpful in optimizing product development. It also helps the DAAC to keep our product related references current. To assist the Langley DAAC in providing the best service to the scientific community, a notification is requested if these data are transmitted to other researchers.
