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MODAPS Services




GES DAAC Transitions Planned

Last Update: June 15, 2022


The GES DAAC has maintained approximately 20 subscriptions for Collection 4 atmospheres and L1 products and for Collection 5 L1 products. These will all be transferred to MODAPS and added to existing MODAPS subscriptions for atmospheres and land products (List of Subscriptions). It is expected that the Collection 4 subscriptions will be transferred in early March and that GES DAAC production will stop thereafter. The Collection 5 subscriptions will be transferred to MODAPS in coordination with the start of Aqua atmospheres reprocessing in early April and Terra reprocessing in early July.

As a consequence of discontinuing Collection 4 and 5 production activities at the GES DAAC and the export of Collection 5 atmospheres products to the GES DAAC, MODAPS will export certain L1 and atmospheres products to the GES DAAC to support their continuing work. These are identified in the List of Subscriptions.


The GES DAAC has maintained 2 post-processor PGEs that generate subsets of L1B products. These will be operated for forward processing in support of the University of Miami and the CERES project. These will be transitioned to MODAPS (List of Subsetters). Products from these subsetters will be distributed through subscriptions.


The GES DAAC operates a number of data services such as pixel and band sub-samplers and subsets for Aeronet. Some of these services are directed toward individual users and some generate data products for groups of users. The former products are generally distributed by subscriptions and the latter are distributed through the data pools. Some products are dynamic in nature in that they may be specified by the users at run time (e.g. the channel subsampler that allows the user to specify what channels will be included in the sub-sample).

Over the period June through September all of these services will be transferred to MODAPS from the GES DAAC. MODAPS will distribute products by subscription or through data pools or will add functionality to LAADS as necessary. Details of these services and the transition schedules can be obtained from Sudipta Sarkar at

Data Production and Archive

The GES DAAC has continued L1B, geolocation, and cloud mask/profiles production for Collection 4 and for Collection 5 starting on dataday January 1, 2005 for both Terra and Aqua. The GES DAAC has also started Collection 5 reprocessing for Terra from first light and, as of August 1, 2006, the leading edge was in early-February, 2002. MODAPS has continued to perform atmospheres and land Collection 4 forward processing using L0 data as input and has exported the atmospheres products to the GES DAAC and the land products to the LP/NSIDC DAACs. The GES DAAC has archived the L1 and atmospheres products and has provided distribution services through EDG and WHOM. These functions will be transitioned to MODAPS.

Collection 4

Since both parties are generating Collection 4 forward processed products, it is expected that the GES DAAC production will cease in early March when the CERES subsetter and the Collection 4 subscriptions have been transitioned to MODAPS. The GES DAAC will continue to archive and provide distribution services for L1B, geolocation, and cloud mask data products prior to dataday early-March 2006 until September 2006. Requests for these products after this dataday until September 2006 and all time intervals after September 2006 will be transitioned to MODAPS (Atmospheres Archive).

MODAPS will continue to export atmospheres Collection 4 data products to the GES DAAC until April 2006 for Aqua and August 2006 for Terra and the GES DAAC will continue to provide distribution services until September 2006. The April and August dates are determined by the advent of Collection 5 atmospheres reprocessing. The September date is determined by the availability of storage at the GES DAAC. The PI Processing (PIP) group determined several years ago that a pre-existing Collection should be maintained for 6 months following the generation of a new Collection. Since Collection 5 atmospheres reprocessing will not be completed until early December 2006, this requirement dictates that the Collection 4 atmospheres products will be archived until early-June 2007. The GES DAAC storage silos will be de-commissioned starting in early 2007 and the GES DAAC will not be able to meet the Collection 4 archive requirements. Consequently the GES DAAC Collection 4 atmospheres L2 holdings will be transferred to LAADS starting in June (LAADS already contains all of the Collection 4 L3 atmospheres products). This transition will be completed by late December and the GES DAAC will not archive and distribute Collection 4 atmospheres data beyond the end of 2006. Users will be able to acquire these data products from LAADS starting in June 2006. Additional details may be found at Production and Distribution.

Collection 5

MODAPS will start Collection 5 Aqua atmospheres reprocessing in early April and Terra reprocessing in early July, 2006. Forward processing will also be started on these dates. All data products will be archived in and distributed from LAADS. The Collection 5 atmospheres data products will not be archived at or distributed by the GES DAAC.

The GES DAAC will stop forward processing distribution services for Collection 5 L1B, geolocation, and cloud mask/profiles at the same time as MODAPS starts Collection 5 forward processing. However, data products from earlier time periods will continue to be distributed by the GES DAAC until early June for Aqua and mid-September for Terra. These dates derive from the need for MODAPS to build up equivalent Collection 5 L1B data holdings as the GES DAAC when the latter ceases distribution services. In order to avoid any discontinuity in data services, the atmospheres Aqua an Terra will be performed out of time order. The reprocessings will start at dataday January 1, 2005 and will continue to the dataday corresponding to the start of Collection 5 forward processing followed by reprocessing from first light through the end of 2004. Additional details may be found at Production and Distribution.

Golden Months

At the request of the PIP, the GES DAAC maintains a "Golden Month" archive of Aqua and Terra atmospheres products for all prior reprocessings including Collections 1, 3, and 4. This Golden Month data set includes all L3 atmospheres products for the entire reprocessing interval plus the L2 products for a 40 day interval. Starting in mid-August 2006 the GES DAAC holdings will be transferred to LAADS and GES DAAC distribution services will cease in mid-October, 2006.

EDOS Interface

At the present time, the GES DAAC is the official L0 archive for Aqua and Terra L0 data. Back-up for this archive is provided by the EDOS archive at White Sands. The GES DAAC acquires the L0 data from EDOS and provides these data to MODAPS through the PDR server. For some time MODAPS has been archiving these data on disk and presently has a complete L0 archive from first light to the present day for both Aqua and Terra.

Starting in early August, MODAPS will begin acquisition of the MODIS L0 data directly from EDOS and the MODAPS archive will become the official L0 archive. Back-up for the MODAPS archive will continue to be provided by the EDOS White Sands archive.

L0 Distribution

The GES DAAC currently provides all L0 data to MODAPS and provides limited quantities to the OCDPS to fill the gaps in their L0 data acquisition from NOAA. The transition of the former has been discussed above. Starting in early April, MODAPS will provide direct access services to the OCDPS to fill their data gaps.

ESDIS has placed a requirement on MODAPS to provide the general user community with access to the L0 archive. Starting in mid-August this service will be provided through LAADS.

ECHO Interface

The GES DAAC currently provides browse and metadata for their data holdings to the ECHO system. This function will be transitioned to MODAPS. In order to ensure no discontinuity to ECHO users, MODAPS will start exporting metadata to ECHO in early June. However, the MODAPS metadata reconciliation capability will not be added until mid-July. This lag results from MODAPS staff limitations. At present there is no operational mechanism for ECHO users to submit a request for GES DAAC data products through ECHO. However, starting in early September this functionality will be added to the LAADS.


MODAPS will generate archive and distribution metrics in coordination with the ESDIS EMS system. Starting in early April all ingest and archive metrics (Ingest Metrics and Archive Metrics) will be generated using the EMS system. Some distribution metrics will be generated by LAADS and some by use of the EMS system (Distribution Metrics). Standard packages will be generated on a weekly basis and will be enhanced by additional material generated for special requests.

User Support

The GES DAAC provides two types of user support. Tier 1 support is provided for logistics and delivery system support for users. In addition, Tier 2 support is provided for users who have questions concerning the science associated with the data products. MODAPS will start to provide Tier 1 and Tier 2 support starting in early April. This will be followed by a period of approximately 6 months when the GES DAAC User Support is phased out.

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