Accomplishment of the GCIP major science objectives involves the development of a comprehensive and accessible observational database for the Mississippi River basin. Volume I of the GCIP Implementation Plan (IGPO,1993) contains information that (1) identifies the sources of observations from existing and planned networks; (2) further enhances those networks where necessary; and (3) assists in developing data sets accumulated from existing observational systems and derived from operational model outputs, such as the NOAA/NCEP Eta regional mesoscale model. The strategic portion of the data management planning (IGPO, 1994b) establishes the implementation strategies needed to achieve the data collection and management objective:
* Provide access to comprehensive in-situ, remote sensing and model output data sets for use in GCIP research and as a benchmark for future studies.
A tactical data collection and management plan is prepared for each definable data set compiled by the Project. This plan is converted to a data summary report when the compiled data set is completed.
A number of GCIP initial data sets (GIDS) were prepared to provide the data services support during the build-up period before the Five-year Enhanced Observing Period (EOP). Preparation of the GIDS started in 1993, and the data sets were compiled for on-line access by GCIP investigators to the extent that is technically feasible. They were also published on a CD-ROM) for wide distribution, especially to international persons interested in performing initial diagnostic, evaluation, and modeling studies on GCIP-related topics. A summary description of the four composite data sets which comprised the GIDS series is given in Appendix D.
The EOP started on 1 October 1995 and will continue for five years. The start date of 1 October was in part chosen to correspond to the start of a water year" as used by the Water Resources groups in organizations such as the U.S Geological Survey. The availability of water data including streamflow data from the USGS National Water Information System is based on the water year. Such data are normally available from this system about six to nine months after the end of the water year. The availability date of these data becomes a primary determining factor in the schedule for the completion of EOP data sets by the GCIP data management system. The data collected during each EOP year will be compiled into a number of standard and custom data sets.
The data collection for the first year of the EOP took account of the following general requirements:
(ii) The CSA data requirements are primarily for the application of energy and water budget studies with a secondary application of model evaluation for the regional model output from the Eta and RFE models.
(iii) An annual data set for the LSA-SW is required for energy and water budgets over an annual cycle plus model evaluations of the regional model output from the Eta, RFE and MAPS.
(iv) A near-surface observational data set from the Little Washita and ARM/CART site is required for the ESOP-96 for land surface process studies, validation and verification of land processing schemes, detailed validation and verification of model output from regional land-atmosphere coupled models and, derivation of surface energy and water budgets.
The responsibilities of the GCIP Data Management and Service System (DMSS) are to provide data services for GCIP investigators, adapt to the evolving data requirements, and compile the information on a five-year consolidated data set at the completion of the EOP. Carrying out these responsibilities involves an implementation approach with evolutionary improvements during the different stages of GCIP.
The DMSS implementation strategy makes maximum use of existing data centers which are made an integral part of the GCIP-DMSS through four data source modules that specialize by data types (i.e., in situ, model output, satellite remote sensing, and GCIP special data). These four data source modules are connected to a GCIP central information source that provides "single-point access" to the GCIP-DMSS. The primary responsibilities for the data source modules along with their major functions and activities were described in Volume III of the GCIP Implementation Plan (IGPO, 1994b).
During the buildup period before the EOP, GCIP made use of an existing data management system operated by the UCAR Office of Field Project Support (UCAR/OFPS) to prepare some initial data sets with online accessibility as an early demonstration system of the planned DMSS capabilities for the EOP. GCIP took advantage of capabilities at several existing data centers to implement a prototype DMSS. This system provides a single-point access for search and order of GCIP data. These data centers each have a capability to transfer small data sets electronically to the user. By the start of the EOP the system began collecting information on the data and is adding to the data services capability that exist at the different data centers. The functions of the In-Situ Data Source Module are being carried out by the UCAR/OFPS.
The Scientific Data Services Section of the National Center for Atmospheric Research (NCAR) is supporting the model output data source module with specific applications to the regional models operated by the NMC in NOAA, the CMC in the AES, and the FSL in NOAA . Approaches and techniques were designed to handle the large volumes of model output data from these regional models. Particular attention was given to the issue of achieving "manageable size" data sets without compromising the information content needed by the GCIP investigators.Further details are given in Section 11.
The design work for the satellite remote sensing data source module took into account the plans now being implemented by NASA, NOAA, and USGS to improve the accessibility of satellite remote sensing data and metadata. GCIP is now working with the Data Archive and Access Center (DAAC), operated at the NASA/MSFC as part of the Global Hydrology and Climate Center (GHCC), to function as the Satellite Remote Sensing Data Source Module for the DMSS.
A GCIP home page" is now available through the World Wide Web with a URL address: