MAIA data and applications

Applications of MAIA data

The NASA MAIA investigation is focused on understanding the health effects of different types (compositional mixtures) of particulate matter (PM) air pollution. MAIA data products will be publicly available free of charge, and are intended to be useful for multiple applications, including the following:

• Health studies: The MAIA data products will provide maps of PM concentrations that can be used to calculate the exposure of populations to various types of PM on a neighborhood scale and on a daily basis. Prospective users include epidemiologists, exposure scientists, and researchers studying the health impacts of air pollution in MAIA target areas.
• Environmental research: Similar to the impacts of air pollution on human health, MAIA data can be used to evaluate the impact on the natural and human environment, by providing 1 kilometer-resolution mass concentrations of various types of PM in the PTAs and - resources permitting - selected STAs. This can be of use to researchers as well as citizen scientists and environmental justice advocates interested in the air quality in their local area.
• Air quality monitoring and regulation: Agencies that regulate and/or monitor air quality within the MAIA target areas may find the data products useful for various applications such as siting monitors, evaluating the impact of regulations, and studying exceptional events.
• Aerosol climatologies and forecast model evaluations: The MAIA data products can be used to characterize the typical seasonal and annual variations of aerosols and PM in the target areas and can also be used to evaluate the accuracy of climate and air quality models.
• Cloud research and cloud-aerosol interactions: the MAIA instrument will capture periodic data over regions of persistent offshore stratocumulus clouds. The MAIA radiance and polarization data from these observations can be used to calculate cloud droplet effective radius and cloud optical depth.

The MAIA team encourages users to explore additional applications of the MAIA data products. Other satellite-based multi-angular radiance and polarization data have been used for studying vegetation characteristics and the three-dimensional structure of clouds and optically thick aerosols. Please consult the Data Product and FAQ sections below to see if MAIA data might be useful to you.

Planned MAIA data products

NASA’s MAIA investigation will deliver a set of standard data products, which will be generated, stored, and distributed at NASA’s Atmospheric Science Data Center (ASDC). Information about these products is shown in the following table. A copy of the data will also be archived and distributed by ASI. MAIA’s core data products will be produced in NetCDF format, with metadata conforming to ISO-3166-1 & ISO-8601 and ISO Metadata Evolution for NASA Data Systems (MENDS) standards. Browse imagery will also be produced.

*IOC refers to “instrument on-orbit checkout,” a period during which the MAIA satellite instrument will undergo post-launch testing before it is ready to start collecting science data.

Generation of all levels of data products will occur in the Primary Target Areas (PTAs) and selected Secondary Target Areas (STAs). Only some product levels will be available in other STAs, Calibration/Validation Target Areas (CVTAs), and Targets of Opportunity (TOOs).

Each target area observed by the MAIA satellite instrument is associated with a nested set of bounding boxes that are centered on the target’s central latitude and longitude. These rectangular bounding boxes describe the geographical extent of MAIA’s data products and ancillary datasets. In addition to the bounding box dimensions shown in the product table, the atmospheric Chemical Transport Model (CTM) used for generating meteorological data and filling PM data gaps is mapped to an area of at least 1080 km x 1140 km. Bounding boxes of each target area can be viewed on a world map using the Geographic Information Visualization Tool (GIVT). For PTAs and STAs, the 360 km x 480 km Level 2/Level 4 bounding boxes are shown. For CVTAs, the bounding boxes shown are truncated to 100 km x 100 km to indicate that the regions of interest for satellite data calibration and validation are very limited in spatial extent.

For any given satellite overpass of a target, the acquired data will not necessarily fill the defined Level 1 or Level 2/Level 4 bounding boxes. The actual geographical area covered by each image depends on the along-track and cross-track angles of view. Images acquired at oblique angles cover a larger portion of the Level 1 bounding box than images acquired when the camera is pointed straight down. Level 2 and Level 4 data products in PTAs and STAs are derived from the area seen in common at multiple step and stare view angles. This common area is defined by the least oblique view since it covers the smallest geographical extent.

Published, peer-reviewed results of health studies conducted by epidemiologists on the NASA MAIA Science Team and their collaborators are also considered a product of the investigation. However, the privacy of the associated health records will be strictly maintained and none of the above products will contain health data.

MAIA Early Adopters Program

MAIA has established an Early Adopters Program aimed at helping those interested in the mission’s data products understand how to use them. Early Adopters receive invitations to events to learn about the mission and the data and can get access to pre-launch simulated data products (see below). Early Adopters also provide important feedback to the MAIA team regarding the extent to which the MAIA data products meet the needs of various communities.

If you are interested in participating in the MAIA Early Adopters Program, please fill out the contact form to be added to the MAIA Community Contacts List and receive notifications of events. If you’re interested in accessing the latest MAIA Simulated Data, be sure to include your NASA Earthdata username.

MAIA Simulated Data Products

Before launch, the MAIA team is working to test the software that will produce the MAIA data products and to generate simulated data in selected target areas in the same format as will be used during the actual mission. These simulated data products are available to MAIA Early Adopters with the goal of facilitating the use of MAIA data post-launch. Early Adopters can determine whether the MAIA products contain the information needed for their work, and begin development of any code, tools, or procedures needed to integrate MAIA data into their workflow.

MAIA Data FAQ

Will MAIA observe the entire globe?

No. Because of the way MAIA measurements are acquired, and due to practical limitations on the amount of data that can be collected, MAIA’s Earth observations will occur only within the target areas.

How often will each MAIA target area be observed by the satellite instrument?

PTAs will be observed at least three times per week, averaged over a season. This is a NASA requirement. Observations of STAs and TOOs will be done on a “best efforts” basis. The frequency with which each STA will be observed typically ranges from about once per week to four times per week, depending on the geographical location. STAs that are near PTAs will be observed less frequently because priority is given to the PTAs. Those STAs that are more geographically isolated can be observed more frequently. TOO observations will occur occasionally. CVTA observations typically will occur monthly.

How often will the surface monitors measure air pollution levels?

Measurements of total PM10 and total PM_2.5 take place at various sampling frequencies depending on the data provider, though typically on an hourly basis. MAIA then processes the measurements to perform quality control and calculate daily averages. Measurements of chemically-speciated PM_2.5 are obtained as daily averages.

In the PTAs where MAIA has deployed equipment, the days on which measurements will be taken will be synchronized with the dates of satellite overpass. In other locations where government-operated speciation samplers exist, such as the U.S., the measurements take place on predefined schedules, usually every third and sometimes every sixth day. Although these dates may not always be coincident with satellite overpasses, there are more monitors in these locations than in places where MAIA has deployed equipment.

What types of PM will MAIA data include?

In the PTAs, the MAIA Level 2 and Level 4 PM data products will include near-surface mass concentrations of total PM₁₀, total PM_2.5, and sulfate, nitrate, organic carbon, elemental carbon, and dust PM_2.5. Please note that some of these species may not be produced in every PTA, depending on the availability of ground monitors measuring these species.

Will all data products be produced in every target area?

All data products will be produced in each of the PTAs. Which data products will be produced in a given STA depends on the purpose of acquiring data over the target and the availability of required input data needed for product generation. STAs observed in sweep mode and CVTAs designated for the maintenance of instrument calibration will only be processed through Level 1.

Does MAIA plan to produce near real-time products?

No. Generation of near-real time products is outside of the project scope.