CIRA is responsible for the implementation and testing of all the software that is necessary to produce the nine standard data products shown in table 1. The challenge, however, is that the software that creates each of these products is being developed by university, or NASA JPL, scientists at remote locations. Each software development team has their own favorite computer and programming language, and their own unique way of reading and writing the science data that is used by their software. In order to set up the CloudSat DPC under the time and cost constraints of the ESSP mission, CIRA and the Science Team Members have worked to together to develop a unique software implementation strategy. The plan works as follows:
All software development, including the system software at the DPC, is done on the same platform. Each system consists of an IBM PC, running the WIN 2000 operating system, and a software package called "Developer Studio".
All of the standard data product applications are written in a common programming language. Each developer is using the FORTRAN 90 programming language, as implemented by Compaq (Compaq Visual FORTRAN).
A web-based system, called the Algorithm Interface Management System (AIMS) was developed to serve as an automated configuration control mechanism for the data processing system at CIRA and for the individual standard data product applications during development.
AIMS allows each software developer to enter the output fields for their product and choose input fields for their application from upstream products. When a developer modifies an output field that is used by downstream applications, AIMS notifies the developers of those applications that a change is pending to their input field. The change is acknowledged by all those affected, and it becomes a documented update to the interface specifications for the products and applications involved. With its integrated configuration control mechanism, AIMS automatically handles application and product versioning when changes affecting other developers are made. As a result, AIMS simplifies the process of interface management and allows asynchronous application development without conflict.
AIMS has been developed to work in concert with CORE. When a standard data product developer specifies the data fields that are required as input in AIMS, he or she can then click on a link in AIMS to automatically generate the FORTRAN code that allows their application to be compiled into and share data with CORE. By using AIMS to generate the CORE interface code, new or revised applications can be integrated into the data processing system in a matter of minutes.
The CORE/AIMS system provides a significant cost savings to a satellite development project. Since the system is both the operational system that will be used during the mission and the system provided to each scientific developer:
a. It minimizes the effort and risk of software implementation. Science code to operational code porting is usually costly, and fraught with peril. It professionals often optimize science code and in the process "break" the algorithm. Scientists often write inefficient code that has inadequate error trapping. These problems are eliminated.
b. It allows scientists to see the context of the code in the larger system. They write code that fits in terms of process control and I/O calls.
c. It makes the scientific algorithm development process much more efficient. The scientist can concentrate on the scientific algorithm and not be burdened with the often time-consuming task of writing I/O routines.
Using this system, the implementation of the standard data products has been extremely smooth. Without the standardization of hardware and code and the implementation of AIMS, the system would have taken at least twice as long (most likely, longer) and future modifications to software would be very complex and costly.
The AIMS database is accessible via the CloudSat Data Processing Center Website. Portions of the interface are only accessible to CloudSat Algorithm Developers or Science Team members, while much is available to the general science community.
Use the following link to view the AIMS interface(will require the one-time setup of a user account).