1- Overview of the Calibration and Validation Plan
2- Organization of the NPP Calibration and Validation Activities
3- NASA Calibration and validation Activities
4- Phasing of activities and evolution of this plan
5- Complete Calibration and Validation Plan in .pdf format

1- Overview of the Calibration and Validation Plan

The NPOESS Preparatory Project (NPP) Instrument Calibration and Product Validation Plan focuses on:

(1) Verification of pre-launch and post-launch instrument characterization and calibration
(2) Assesment of operation and science algorithms
(3) Validation of operational and science products
(4) Evaluation of overall system performance
(5) Identification of resources that are needed to carry out this plan

The plan introduces the NPP and the instruments to be flown, describes the associated products, details pre-launch characterization and calibration efforts using NIST traceability, lists the validation approaches for the level 1 and 2 products (including ancillary data from ground based, airborne, and other satellite systems), and recommends data processing support necessary for quality assessment.

The plan also includes NPP product performance requirements, lists of characterization and calibration tests, summaries of field experiments and ground networks involved in the NPP Cal/Val, and various science supporting references.

The plan is specific to the NPP mission and it addresses only those sensors (currently VIIRS, CrIS and ATMS) that are on NPP and their specific EDRs and CDRs. The activities conducted under this plan will serve as pathfinder to the subsequent task of characterizing and calibrating the full suite of sensors and validating the full suite of EDRs during the NPOESS era.

As other government-sponsored participants are identified, this plan will be expanded to include them by incorporation of, or reference, to their independent plans. A separate plan will be developed to reflect the coordination of the government-sponsored activities with those detailed here.

2- Organization of the NPP Calibration and Validation Activities

A Government Team will participate in the characterization, calibration and validation of the sensors, algorithms and data products of the NPOESS Preparatory Project (NPP). The Government Team’s role is to provide government expertise where appropriate and to assess the final results on behalf of the U.S. government.

The Government Team consists of two coordinated activities; one funded and managed by NASA Calibration and Validation Team activities, conducted by the Global Change Science Team (GCST) and the NPP Calibration Support Team (NCST). The second is the IPO Cal/Val Team, which is made up of the Science and Engineering Team from the IPO Internal Government Studies (IGS) Program and the IPO Operational Algorithm Teams (OATs).

These activities will be, in turn, coordinated with those of the IPO’s NPOESS Engineering and Manufacturing Development (EMD) contractor. The EMD contractor, called also the NPOESS Shared System Performance Responsibility (SSPR) contractor, has responsibility to develop the sensors, algorithms and data production systems, and to assure the quality of the resultant Environmental Data Records (EDRs). The SSPR program will include the activities of the Sensor/Algorithm Subcontractors. The selection of the SSPR contractor is scheduled for August 2002.

3- NASA calibration Validation Activities

The independently managed NASA activity utilizing NPP is primarily within the Global Change Science Team (GCST) which consists of a competed science team supported by NASA internally funded project activities. Key government participants are drawn from the NASA Goddard Space Flight Center, the Langley Research Center, and the Jet Propulsion Laboratory. The NASA airborne science program serves as a resource for both the IPO supported and NASA supported activities. A NASA Research Announcement (NRA) will be used to solicit proposals for specific activities (including Calibration/Validation) by university, government, and corporate investigators.

The Project Scientist will manage an NPP Calibration Support Team (NCST), to develop research quality Level 1B data products for VIIRS, CrIS, and ATMS. NCST will work with the government partners and the contractors to assure that the sensors are fully characterized and calibrated during the pre-launch and post-launch phases. NCST will conduct coordinated analyses of the data and instrument trending during the NPP mission, and share these results with the IPO and the sensor vendors in a timely manner.

NASA will oversee the validation of research products and global change data sets generated by the GCST in the Science Data Segment (SDS). The results of the validation activities by the GCST will be incorporated to provide guidance to the IPO in its evaluation of the EMD performance and to suggest and/or provide algorithm improvements.

Pre-launch activities focus on development of validation procedures, preliminary validation of new algorithms (and radiative transfer models) using existing space-borne and airborne sensors, verification and characterization of instrument performance over the ranges of operation, and estimation of the precision, accuracy, and overall uncertainty of the derived products. An essential feature of the plan is NIST traceability. Post-launch emphasis is on sensor calibration and validation of data products, leading to algorithm refinement.

Validation will be conducted using independent means to assess uncertainties of geophysical data products derived from instrument system outputs. This is generally approached by direct comparison with independent correlative measurements from ground-based networks, comprehensive test sites, and field campaigns, along with comparisons with independent satellite retrieval products from instruments on the same and different platforms. It is essential to have an integrated strategy for validation, including contributions from airborne field campaigns, surface networks, as well as satellites.

Sensor Test Data

The Government Team will work closely with the vendors during the pre-launch testing and characterization to assure that the post-launch instrument performance is understood, and sensors’ radiance is correctly modeled, assimilated and tested.

Simulated data

The Government Team will work closely with the vendors to assure that the sensors’ radiance and EDRs are correctly simulated, and performance of EDRs’ algorithms and quality of products are carefully tested using simulated data.

Aircraft Validation Data

Aircraft data is important to the program both before and after launch. Before launch, it provides the means to demonstrate expected product performance and to establish algorithm approaches that will work in the presence of actual environmental conditions. After launch, it is a major part of system validation. The NAST, Scanning HIS, MAS, PSR, APMIR, MASTER and AVIRIS aircraft instruments are key components for performing product validation.

Other Sensors Validation Data

Similarly, data from precursor sensors are used to test algorithms in the pre-launch phase and to validate the data products from the NPP sensors. MODIS serves as the source of test data for VIIRS algorithms. AIRS will serve as the source of test data for CrIS while AMSU/HSB will serve as the source for ATMS. Validation will be done against these sensors plus OLS and AVHRR for VIIRS and HIRS/AMSU and possibly IASI/AMSU for CrIS/ATMS.

Coordinated Measurement Campaigns.

It is important for the Government Team to plan for the necessary data gathering and data analysis which can suggest instrument processing adjustments and algorithm evolution that will foster the maximum utilization of NPP data. This will be an intensive effort after CrIS, VIIRS, and ATMS launch on NPP and continue throughout the life of NPP and after that through the NPOESS era.

IPO and NASA began conducting missions with the NAST, S-HIS, and MAS instruments in 1997 and will continue such missions throughout the remainder of this decade. Significant missions already conducted include the SAFARI mission at EOS sites in South Africa, and a joint water vapor experiment with the DOE centered around the Atmospheric Radiation Measurement (ARM) site in Oklahoma. NOAA has been and will continue to conduct Calibration/Validation of the operational polar orbiting visible and infrared imagers and the infrared and microwave sounders throughout the decade; DoD has been and will continue to conduct Calibration/Validation of the operational polar orbiting microwave imagers and sounders and visible/infrared imagers throughout the decade; inter-calibration of the ongoing series of POES and DMSP sensors and the associated sounding and imaging products is a high priority for these efforts.

Major expenses such as ship and aircraft deployments and other field campaigns will be jointly funded and managed. In addition, many of these activities will benefit from other agency programs. Key among those are the ongoing activities of the NASA-EOS program, ARM-CART program of DOE, the LTER program of NSF, the operational Calibration/Validation programs of NOAA, DoD and IPO, ENVISAT calibration validation program, and programs such as NASA’s AERONET and MOBY future field campaigns.

Data Processing

NPP data will be processed at two facilities: 1. NASA Science Data Segment (SDS) for climate research purposes, and 2. Interface Data Processing Segment (IDPS), requiring operational capabilities;

The NASA Science Data Segment (SDS) will provide a production facility with reprocessing capabilities of NPP data, using algorithms developed by the GCST. Their data products are identified as Level 1B and Climate Data Records (CDRs) since they will be optimized for climate studies. The SDS will also support access to RDRs, and selected SDRs and EDRs processed at IDPS to support validation activities by the GCST teams. The SDS will maintain a store of all mission data for the life of the mission, except SDRs and EDRs.

4- Phasing of Activities and Evolution of This Plan

The plan is expected to evolve. The activities detailed here are already underway and they will continue through to the end of the NPP mission. Post-launch activities will peak in the year following the launch of NPP assuming full delivery of all data products is underway by launch plus six (6) months. Sustaining and intermittent Calibration/Validation activities will continue throughout the NPP mission and should overlap the first NPOESS satellite system Calibration/Validation efforts. The plan will be updated periodically.

5- Complete Calibration and Validation Plan in .pdf format