Title: Ocean PEATE
1Ocean PEATE
- Fred Patt
- NPP SDS Peer MOR
- Building 8 Auditorium
- August 27, 2008
2Ocean PEATE Agenda
- Ocean PEATE Overview
- Implementation Status
- Documentation
- Support Staff
- EDR Assessment
- Issues/Concerns
3Ocean PEATE Overview
- The NPP Ocean PEATE will be implemented within
the framework and facilities of the current NASA
Ocean Data Processing System (ODPS) - This system has been successfully supporting
operational, satellite-based remote-sensing
missions since 1996, and its capabilities
continue to evolve and expand to meet the demands
and challenges of future missions.
4Ocean PEATE Functions
- Acquire VIIRS RDRs, SDRs, and Ocean EDRs from the
SD3E and ADS/CLASS - Assess the quality of the NPP Ocean EDRs for
accomplishing NASAs climate research
requirements - Provide suggested algorithm improvements to the
IDPS via the Project Science Office Element
(PSOE) - Process selected data subsets in support of
Evaluation and Validation activities
5Ocean PEATE Interface Diagram
Analysis Results, Proposed Algorithm Updates
xDRs, IPs, Ancillary Data
Management Direction
xDRs, IPs, Ancillary Data (if unavailable from
SD3E)
OceanPEATE
Pre-flight Algorithms, Data, Info
Software, Data
Alternate Ancillary Data
xDR Eval. Results, Algorithm Updates
Calibration Updates and Evaluations
Interaction
In Situ Data
In Situ Data
Algorithm Updates, Test Requests Results
Matchups
6Ocean PEATE External Interfaces (1 of 2)
- SDS Science Data Distribution and Depository
Element (SD3E) - Provides NRT access to raw data
- Primary source of RDRs
- Provides selected SDRs and EDRs
- SDS Integration and Test System Element (ITSE)
- Build and test updates to operational code in
mini-IDPS - Run tests on selected data per request of PEATE
- Archive Distribution Segment (ADS)
- Primary source for archived data
- xDRs, IPs, Ancillary Data, Operational
Algorithm/Source Code and Calibration Products - Ancillary Data Providers (ADP)
- Provides alternate ancillary data sets (e.g.,
ozone, meteorological data sets) - CasaNOSA
- Serves as the NPP pre-flight repository of
Government held data for distribution to
Government user teams - Place to acquire pre-launch NPP algorithms and
supported data files
7Ocean PEATE External Interfaces (2 of 2)
- NASA VIIRS Ocean Science Team (VOST)
- Coordinate activities with PEATEs and PSOE on xDR
and recommended algorithm improvements. Supports
Independent Calibration Validation Activities - NPP Instrument Calibration Support Element
(NICSE) - Provides alternative calibration LUTs and
recommended improvements to calibration
algorithms - PEATE provides results of LUT and algorithm tests
- Project Science Office Element (PSOE)
- Provides management direction
- Accepts algorithm update recommendations
- SeaBASS/ODPS
- Provides Ocean Color in situ data
- RSMAS/U. Miami
- Provides SST in situ locations
- PEATE provides SST EDR matchups
- Ocean Science Community
- Relies on Ocean PEATE to provide evaluation
products and results
8Roles Responsibilities of Science Team / PEATE
PEATE Science Team
Acquire, catalog, and distribute xDRs Perform automated matchups with SeaBASS data Subscribe, browse, download xDRs Evaluate Ocean EDRs using matchups
Generate Level-3 products from Ocean EDRs Compare VIIRS Ocean Level-3 files with heritage sensors
Acquire test LUTS from NICSE Evaluate VIIRS calibration using test LUTS
Deliver/install recommended software updates at ITSE Generate recommended algorithm changes
Upload RDRs to ITSE, input test run requests and download SDRs and/or EDRs Develop algorithm test cases and scenarios and evaluates test products
Interface with SDS, ITSE, ADS, Provide feedback to Project Scientist
9Ocean PEATE Agenda
- Ocean PEATE Overview
- Implementation Status
- Documentation
- Support Staff
- EDR Assessment
- Issues/Concerns
10ODPS Design Overview
- Fully automated, distributed data system for
acquiring, processing, archiving, and
distributing scientific data - Highly scalable
- Easily adaptable to support multiple concurrent
missions - Graphical user interfaces for controlling and
monitoring system functions and activity - Non-platform specific
11ODPS COTS and Freeware
- Linux OS (CentOS 4.x)
- Solaris OS
- Sybase RDBMS
- Subversion (source code management)
- Pro-active DBA
- Interactive Data Language (IDL)
- Generic Mapping Tool (GMT)
- Netpbm (graphic image toolkit)
- HDF5 Library
- Languages C, PERL, SQL
12ODPS Architecture Hardware
- Processing Servers
- Intel-based dual Xeon / AMD-based dual Opteron
- 8 GB RAM
- Five 72 GB SCSI drives
- Storage Servers
- Intel-based P4 / AMD-based single Opteron
- 1 GB / 2 GB RAM
- 1.5 TB IDE RAID 5 (3ware) / 9.6 TB SATA RAID 6
(Areca) - 2 hot spare drives per RAID5
- Database Server
- Sun V880
- 8-16 GB RAM
- 6-12 70 GB SCSI HDD
13ODPS Current Components
14Building 28 Room W220 Computing Facility
15Reliability and Redundancy
- Critical components (database server, network
systems) have full maintenance contracts to
ensure rapid response to problems - Multiple-server components (ingest, processing,
storage, distribution) have substantial
redundancy to maintain full capability spares
maintained for rapid replacement. - Testing nodes are separated from mainstream
production components.
16Technology Refresh
- Hardware technology advances (CPU, storage) are
continuously monitored to select new components
for evaluation. - Typical upgrade threshold is a doubling in
capacity (18 months). - Two generations of hardware are generally in use.
- Candidate components are procured, installed in
testing cluster and rigorously evaluated in a
production-like environment. - Following successful evaluation, multiple copies
are procured, installed, tested and swapped in
for older components. - ODPS design allows new components to be rapidly
added to resource tables without interrupting
system operations. - Performance of new components is closely
evaluated following installation in operations
environment. - Critical components are run in parallel with
existing system to ensure reliability under
production loading.
17Existing Software Reuse
- ODPS Components
- Database
- VDC/Scheduler
- Data Acquisition and Ingest
- Level-3 Scheduler
- File migration and management
- Archive Device Manager
- Data distribution
- Level-2 multi-mission software (vicarious
calibration) - Level-3 multi-mission software (long-term trends
and comparisons - Level-2 to Level-3 comparison software (residual
sensor errors) - SeaBASS (in situ data management)
- Matchup/extraction software
18Ocean PEATE New Capabilities (1 of 2)
- Acquire, ingest and catalog NPP VIIRS data
products RDRs, SDRs and Ocean EDRs (Data
Acquisition Ingest, Device Manager and File
Migration and Management). - Status Initial interface test run with SD3E.
- Process selected Ocean EDRs (SST and OCC) to
Level-3 to support data product and algorithm
evaluations (Level-3 Scheduler, VDC and Level-3
binner). - Status Prototype Level-3 processing has been
demonstrated using sample IDPS Build 1.4 OCC and
SST EDRs. - Perform VIIRS OCC EDR matchups with SeaBASS Ocean
Color in situ data (extract code). - Status Pending re-test of acquisition and ingest
capabilities with latest IDPS build.
19Ocean PEATE New Capabilities (2 of 2)
- Incorporate VIIRS SDR processing for vicarious
calibration analysis. - Status Pending re-test of acquisition and ingest
capabilities with latest IDPS build. - Produce VIIRS proxy data using VOST-developed
software (VDC/Scheduler). - Status Under development
- Acquire SST in situ data from RSMAS and perform
matchups with SST EDRs - Status SST acquisition in place for MODIS
matchups pending re-test of acquisition and
ingest capabilities with latest IDPS build. - Support browse and distribution of data products
for team members (Data Distribution). - Status Pending re-test of acquisition and ingest
capabilities with latest IDPS build.
20Ocean PEATE Data Storage Estimate
Data Type Daily 1 Year 5 Years
RDR 150 GB 53.5 TB 268 TB
SDR (M-band) 242 GB(2) 8.6 TB(1,2) 43 TB(1,2)
OCC EDR 84 GB 3 TB(1) 15 TB(1)
SST EDR 19 GB 0.7 TB(1) 3.4 TB(1)
Inter. Products 70 GB N/A N/A
Ancillary Data 0.1 GB .04 TB .2 TB
Total 565 GB 66 TB 330 TB
- Assumptions
- Long-term storage is sized for 100 of RDRs and
10 of SDRs and EDRs - SDR volume includes geolocation
21New Hardware for the Ocean PEATE
- 7 Storage Servers _at_ 9.6 TB first-year VIIRS
data storage - Additional servers acquired post-launch to handle
years 2 5 - No new processing or network capacity required
technology refresh cycle to be continued within
the ODPS as described.
22Ocean PEATE Build Schedule
- Build 1 (L-18 months)
- All interfaces fully implemented and tested
- Verify initial versions of operational code
ported and running in ITSE - L-3 product code developed and tested
- Prelaunch VIIRS test data storage and SDS
interface testing support with existing ODPS
storage capacity - Initial test products generated for review by
VIIRS Ocean Science Team
- Build 2 (L-12 months)
- Routine exercise of interfaces to acquire proxy,
surrogate (Aqua?) and/or simulated data - Verify pre-launch version of operational code
running in ITSE - Browse and distribution capability developed and
tested - Test products routinely acquired as available and
posted for access by VIIRS Ocean Science Team - Data storage for one year
23Ocean PEATE Testing Status (1 of 6)
Req. Requirement Support Verification Status
3.4.1.1 PEATEs xDR Ingest from the SD3E New Data Acquisition and Ingest Interface Test X
3.4.1.2 PEATEs IP Ingest from the SD3E New Data Acquisition and Ingest Interface Test
3.4.1.3 PEATEs Official Ancillary Data Ingest from the SD3E New Data Acquisition and Ingest Interface Test
3.4.1.4 PEATEs Calibration Product Ingest from the SD3E New Data Acquisition and Ingest Interface Test
3.4.1.5 PEATEs Request Listings New Data Acquisition and Ingest Interface Test X
3.4.1.6 PEATEs Product Subscriptions from the ADS PEATE Personnel Interface Test
3.4.1.7 PEATEs Ad-hoc Requests to the ADS PEATE Personnel Interface Test
3.4.1.8 PEATEs xDR Ingest from the ADS New Data Acquisition and Ingest Interface Test
3.4.1.9 PEATEs Official Ancillary Data Ingest from ADS New Data Acquisition and Ingest Interface Test
3.4.1.10 PEATEs Calibration Product Ingest from ADS New Data Acquisition and Ingest Interface Test
24Ocean PEATE Testing Status (2 of 6)
Req. Requirement Support Verification Status
3.4.1.11 PEATEs IP Ingest from the ADS New Data Acquisition and Ingest Interface Test
3.4.1.12 PEATEs ADS Query and Request Status Ingest PEATE Personnel Interface Test
3.4.1.13 PEATEs Alternate Ancillary Data Ingest Existing ODPS Capability Inspection X
3.4.1.14 PEATEs Pre-launch Data Ingest Existing ODPS Capability Inspection X
3.4.1.15 PEATEs Engineering Service Ingest PEATE Personnel Interface Test
3.4.2.1 Store/Catalog Data New Data Management ITSE Functional Test X
3.4.3.1 Manage Software Configuration Existing Subversion Repository Inspection X
3.4.4.1 Operational Algorithms Ingest from the SD3E ITSE Functional Test
3.4.4.2 PEATEs Management Direction Ingest PEATE Personnel Interface Test
3.4.4.3 PEATEs Instrument Service Report Ingest PEATE Personnel Interface Test
25Ocean PEATE Testing Status (3 of 6)
Req. Requirement Support Verification Status
3.4.4.4 PEATEs NICSE Cal LUT Ingest ITSE Interface Test
3.4.4.5 PEATEs ITSE Algorithm Status PEATE Personnel Interface Test
3.4.4.6 Pre-Launch Assessment New PEATE Tool Development Functional Test
3.4.4.7 xDR Implementation Assessment ITSE Functional Test
3.4.4.8 EDR Algorithms ITSE Functional Test
3.4.4.9 SDR and EDR Testing Environment ITSE Functional Test
3.4.4.10 Comparison Tools Development Existing ODPS Capability Inspection X
3.4.4.11 Comparing against Other Data New Level-3 Processing Functional Test
3.4.4.12 Comparing against Other Products New Level-3 Processing Functional Test
3.4.4.13 Analyzing Algorithm Improvement/ Enhancement ITSE/Ingest Interface/ Functional Test
26Ocean PEATE Testing Status (4 of 6)
Req. Requirement Support Verification Status
3.4.4.14 Generating SDR ITSE Functional Test
3.4.4.15 Generating EDR ITSE Functional Test
3.4.4.16 Test Data VOST Simulation Software / ODPS New Data Processing Design
3.4.4.17 Developing SDR Algorithm Improvement/Enhancement ITSE Functional Test
3.4.4.18 Developing EDR Algorithm Improvements/Enhancements ITSE Functional Test
3.4.4.19 Testing Algorithm ITSE/Acquisition and Ingest Functional/ Interface Test
3.4.4.20 Documentation ODPS Web Site Inspection X
3.4.4.21 PEATEs Management Report PEATE Personnel Interface Test
3.4.4.22 PEATEs Instrument Service Request PEATE Personnel Interface Test
3.4.4.23 PEATEs Quality Control Response ITSE Functional Test
27Ocean PEATE Testing Status (5 of 6)
Req. Requirement Support Verification Status
3.4.4.24 PEATEs xDR Ingest from the SD3E New Data Acquisition and Ingest Interface Test
3.4.5.1 PEATEs Science Data Export New Product Distribution Interface Test
3.4.5.2 PEATEs Data Compression Existing ODPS Capability Inspection X
3.4.8.1 Ocean Product Assessment New and Existing ODPS Capabilities Functional Test
3.4.8.2 Ocean EDR Evaluation New and Existing ODPS Capabilities Functional Test
3.7.1 Mission Support All New Capabilities Aggregate of All Testing
3.7.3 Availability Existing ODPS Capabilty Inspection X
3.7.4 System Failure Existing ODPS Capabilty Inspection X
3.7.5 Operational Duty Cycle Existing ODPS Capabilty Inspection X
3.7.6 Design Life New Data Product Storage Inspection
28Ocean PEATE Testing Status (6 of 6)
Req. Requirement Support Verification Status
3.7.7 Maintainability Existing ODPS Capability Inspection X
3.7.8.1 Unclassified Security Restriction Existing ODPS Facility Inspection X
3.7.8.1 Complying with NASA Security of Information. Technology1 Code 600 Security Plan Inspection X
3.7.8.1 Operators Access and Privilege Existing ODPS Capability Inspection X
3.7.8.1 SDS Data Verification New Data Acquisition and Ingest Interface Test
3.7.9 Data Integrity New Data Acquisition and Ingest Interface Test
29Ocean PEATERequirements Implementation
- 98 of requirements (55) implemented by Build 2
add additional storage capacity before launch
30Sustaining Operations and Maintenance
- ODPS runs 24x7 with on-site support 8x5.
- Support is shared across all projects.
- Staffing needs are covered by existing OBPG
support personnel.
31Ocean PEATE Agenda
- Ocean PEATE Overview
- Implementation Status
- Documentation
- Support Staff
- EDR Assessment
- Issues/Concerns
32Documentation
- Ocean PEATE Level 4 Requirements and Operations
Concept - ICDs
- SD3D to PEATEs
- MOU with RSMAS
- ODPS Project Data Management Plan (review)
- ODPS Software Management Plan
- Network IT Security Plan
33Ocean PEATE Agenda
- Ocean PEATE Overview
- Implementation Status
- Documentation
- Support Staff
- EDR Assessment
- Issues/Concerns
34Ocean PEATE Team
- Ocean PEATE Management
- Gene Feldman
- Fred Patt
- Validation Support
- Sean Bailey
- Jeremy Werdell
- Software Support
- Bryan Franz
- Joel Gales
- Data System
- John Wilding
- Dan Knowles
- Muriel Taylor
- Systems Management
- Paul Smith
- Joe McSorley
- Chris Moellers
35Ocean PEATE Staffing Levels
- All staffing needs will be met with existing OBPG
staff - Increases will be accommodated as other projects
(e.g., MODIS Aqua) wind down.
36Ocean PEATE Agenda
- Ocean PEATE Overview
- Implementation Status
- Documentation
- Support Staff
- EDR Assessment
- Issues/Concerns
37VIIRS Ocean Products for Evaluation
- All VIIRS Ocean products to be evaluated will be
acquired from the IDPS, ADS/CLASS, or the ITSE. - Testing and evaluation of algorithm changes will
require regenerating product time series in the
ITSE, to be downloaded to the Ocean PEATE. - The Ocean PEATE will design changes to the code
in the ITSE for the purpose of algorithm
improvement or problem resolution, develop
appropriate test cases and request runs to verify
and evaluate the changes.
38IDPS VIIRS Ocean EDR Data Flow
Processing Module
VIIRS Product
VIIRS RDR
Dynamic Ancillary Data
Previous VIIRS Gridded Products
Static Ancillary Data
Previous VIIRS Gridded Products
NAAPS TOD
MODIS Land/Water Mask
NCEP Geopotential Height
Ancillary Files
Ancillary Files
DEM
NDT
39IDPS VIIRS Ocean EDR Data Flow
VIIRS Geolocation
VIIRS SDR
Processing Module
VIIRS_SDR_01 RDR Decompression
VIIRS_GEO_01 Geolocation
VIIRS_SDR.IM 375m SDR
VIIRS_SDR.MOD 750m SDR
VIIRS SDR
VIIRS Product
VIIRS RDR
Dynamic Ancillary Data
Previous VIIRS Gridded Products
Static Ancillary Data
Previous VIIRS Gridded Products
NAAPS TOD
MODIS Land/Water Mask
NCEP Geopotential Height
Ancillary Files
Ancillary Files
DEM
NDT
40IDPS VIIRS Ocean EDR Data Flow
VIIRS Geolocation
VIIRS SDR
Processing Module
VIIRS_SDR_01 RDR Decompression
VIIRS_GEO_01 Geolocation
VIIRS_SDR.IM 375m SDR
VIIRS_SDR.MOD 750m SDR
VIIRS SDR
VIIRS Product
VIIRS RDR
Dynamic Ancillary Data
Previous VIIRS Gridded Products
Static Ancillary Data
Previous VIIRS Gridded Products
VIIRS_GD_08 750m Granulation
NAAPS TOD
VIIRS_GD_25 NAAPS Granulation
MODIS Land/Water Mask
VIIRS_GD_27 L/W Mask Granulation
NCEP Geopotential Height
Ancillary Files
Ancillary Files
VIIRS_GD_11 Ancillary Profile
VIIRS_GD_09 GFS Granulation
ALL_GD_01 Time Interpolation
VIIRS_GD_28 Surface Pressure Adjustment
VIIRS_GD_12 Bathymetry Granulation
DEM
VIIRS_GD_13 Temperature Granulation
NDT
41IDPS VIIRS Ocean EDR Data Flow
VIIRS Geolocation
VIIRS SDR
Processing Module
VIIRS_SDR_01 RDR Decompression
VIIRS_GEO_01 Geolocation
VIIRS_SDR.IM 375m SDR
VIIRS_SDR.MOD 750m SDR
VIIRS SDR
VIIRS Product
VIIRS RDR
Dynamic Ancillary Data
Previous VIIRS Gridded Products
Static Ancillary Data
Previous VIIRS Gridded Products
VIIRS_GD_08 750m Granulation
NAAPS TOD
VIIRS_GD_25 NAAPS Granulation
MODIS Land/Water Mask
VIIRS_LN_06 Active Fires
VIIRS_CM_01 Cloud Mask
VIIRS_GD_27 L/W Mask Granulation
NCEP Geopotential Height
Ancillary Files
Ancillary Files
VIIRS_GD_11 Ancillary Profile
VIIRS_GD_09 GFS Granulation
ALL_GD_01 Time Interpolation
VIIRS_GD_28 Surface Pressure Adjustment
VIIRS_GD_12 Bathymetry Granulation
DEM
VIIRS_GD_13 Temperature Granulation
NDT
42IDPS VIIRS Ocean EDR Data Flow
VIIRS Geolocation
VIIRS SDR
Processing Module
VIIRS_SDR_01 RDR Decompression
VIIRS_GEO_01 Geolocation
VIIRS_SDR.IM 375m SDR
VIIRS_SDR.MOD 750m SDR
VIIRS SDR
VIIRS Product
VIIRS_SN_02 Ice Quality
VIIRS RDR
Dynamic Ancillary Data
Previous VIIRS Gridded Products
Static Ancillary Data
VIIRS_CL_01 Cloud Optical Properties
Previous VIIRS Gridded Products
VIIRS_ST_02 Surface Temp
VIIRS_GD_08 750m Granulation
NAAPS TOD
VIIRS_SN_03 Ice Concentration
VIIRS_GD_25 NAAPS Granulation
MODIS Land/Water Mask
VIIRS_LN_06 Active Fires
VIIRS_CM_01 Cloud Mask
VIIRS_GD_27 L/W Mask Granulation
NCEP Geopotential Height
Ancillary Files
Ancillary Files
VIIRS_ST_01 Sea Surface Temperature
SST EDR
VIIRS_GD_11 Ancillary Profile
VIIRS_GD_09 GFS Granulation
VIIRS_AR_01 Aerosol Type
ALL_GD_01 Time Interpolation
VIIRS_GD_28 Surface Pressure Adjustment
VIIRS_OC_01 Ocean Color / Chlorophyll
VIIRS_GD_12 Bathymetry Granulation
OCC EDR
DEM
VIIRS_GD_13 Temperature Granulation
NDT
43ODPS MODIS Ocean Product Data Flow
Processing Module
MOD_PR01 Level-0 to 1A
MODIS Product
Dynamic Ancillary Data
MODIS Level-0
MODIS Level-1A
Static Ancillary Data
MODIS 1 km Level-1B
MOD_PR03 Geolocation
MOD_PR02 Level-1A to 1B
MODIS SST
Platform ATTEPH Data
MSl12 Level-1B to 2
MODIS Geolocation
MODIS Ocean Color
MET Ancillary Data
Ozone Ancillary Files
Land/Water Mask
44Ocean Team Algorithm Change Process
N
ST member develops evaluation strategy
Products improved?
PEATE staff request ITSE granule-level test
ST analyzes products and test results
Y
PEATE staff upload test input data and
request evaluation test run
ST member identifies algorithm change
ITSE performs test run
ST provides algorithm change recommendation to
PSOE
ST member and PEATE staff develop code change
PEATE retrieves test products
ITSE performs test run
PEATE and ITSE staff install and build code change
ST member verifies test products
PEATE retrieves test products
N
Expected results?
Code correct?
Y
N
Y
ST member evaluates test products
PEATE and ST member check code change
45Evaluation vs. Product Level
- Granule-based Evaluations
- Level-1 (SDR) Evaluations
- Onboard calibration analyses
- Vicarious calibration
- Level-2 (EDR) Evaluations
- Matchup analyses
- Flag analyses
- Time Series Evaluations
- Level-2 (EDR) Evaluations
- Residual detector (striping) and scan (RVS)
dependence - Level-3 Product Evaluations
- Sensor and algorithm comparisons
- Temporal anomaly evaluations
46Vicarious Calibration
- Vicarious calibration using surface measurements
(e.g., MOBY) gives constant gain correction to
TOA radiances over the mission - Analyses of calibration results provide insight
into temporal and geometric sources of variation.
47Vicarious Calibration
- Strengths
- Fine-tuning of sensor absolute radiometric
response allows for correction of prelaunch
radiometric calibration - Limitations
- System-level calibration that incorporates
atmospheric correction into measurements,
convolving algorithm and sensor effects. - One-time gain correction per band for the entire
sensor lifetime assumes sensor stability has
already been established through other means not
a substitute for lack of instrument
characterization. - Observation limitations and rigorous data quality
control severely restrict the number of useful
measurements (typically 1 or 2 per month per
site). - Specific to ocean algorithms, not applicable to
other surface types. - Availability of MOBY or equivalent is unknown for
VIIRS.
48Matchup Analysis
- Ocean data granules in ODPS catalog are
automatically matched with in situ data - SeaWiFS Bio-optical Archive and Storage System
(SeaBASS) stores and manages in situ holdings
from field programs and supported investigators. - Ocean staff acquire, QC and analyze new data
samples. - Over 60,000 in situ profiles stored covering
SeaWiFS/ MODIS time frame.
49Matchup Process Flow Chart
50Matchup Analysis
- Strengths
- The only truly independent validation of the
science data products using ground truth
measurements. - Limitations
- Quality of in situ data is highly variable and
difficult to assess. - Coverage for OC in situ data is limited, both
geographically and temporally. - Assumes that highly localized (meters)
measurements are representative of pixel (km)
area. - In situ measurements require discipline expertise
to analyze and compare with satellite values - Generally useful only for assessing static biases
in final products. - Availability of in situ data in VIIRS timeframe
is unknown. -
51Flag Analyses
- Determine loss of coverage resulting from each
flag - Verify effectiveness of flags at removing invalid
or questionable data
50-meter depth
Sensor zenith
52Residual Detector Dependence
- Level-3 multi-day products (same or different
sensor) are resampled to generate values at
Level-2 resolution. - Comparisons are performed by detector and mirror
side to evaluate residual detector response
errors
53Residual Scan Dependence
- Level-3 multi-day products (same or different
sensor) are resampled to generate values at
Level-2 resolution. - Comparisons are performed by pixel number and
mirror side to evaluate residual response-vs-scan
(RVS) errors
54Residual Detector/Scan Dependence
- Strengths
- Provides evaluation of response vs. detector,
scan angle and mirror side independent of onboard
calibration. - Can also be used to evaluate errors in other
sensor characteristics - Limitations
- Works well mainly in temporally stable areas.
- Noise levels may be large compared with residual
errors.
55Level-3 Product Generation
- Sensor, algorithm and interannual comparisons
require Level-3 binned (equal-area) products. - The Ocean PEATE is implementing software to
process VIIRS EDRs to Level 3 binned products in
current ODPS (SeaWiFS-like) format. - Use current binning code with new input functions
to read EDRs - This will automatically provide the additional
capabilities to produce multi-temporal
composites, standard mapped image (SMI) products
and Level-3 browse files. - Time-series analyses of recommended algorithm
changes will require reprocessing EDRs in the
ITSE.
56Sensor and Algorithm Comparisons
- Level-3 parameters (e.g., nLw) compared for
common spectral bands - Common bins extracted and compared over the
period of overlap between the sensors - Comparisons are performed globally (deep water,
oligotrophic, mesotrophic, eutrophic), zonally
and for specified regions.
57Zonal Cross-Comparisons
58Chlorophyll Image Comparisons
SeaWiFS Deep-Water Chlorophyll 2002 193
MODIS Deep-Water Chlorophyll 2002 193
SeaWiFS Deep-Water Chlorophyll 2006 365
MODIS Deep-Water Chlorophyll 2006 365
59Level-3 Comparisons
- Strengths
- Sensitive to small differences in products from
different sensors or algorithms. - Excellent coverage available, both temporal and
geographic. - Can assess continuity among data sets (Climate
Data Records) - Limitations
- No obvious truth in comparisons.
- Sensitive to band-pass differences.
- May be affected by time-of-observation
differences. - Availability of other sensors for comparison
(SeaWiFS or MODIS) is unknown climatology is
available as an alternative
60Temporal Anomaly Evaluations
- Level-3 global averages for the entire mission
are fit to a periodic function to remove natural
annual variability. - The differences between the global averages
and the annual cycle are then plotted over the
mission. - The results show both geophysical variations
and any unexpected changes due to uncharacterized
instrument effects or algorithm artifacts.
61Temporal Anomaly Example
62Temporal Anomaly Evaluations
- Strengths
- Very sensitive to small changes in sensor
performance - Limitations
- Difficult to distinguish sensor from real
geophysical changes. - Can be affected by sampling variations.
63Issues/Challenges/Concerns
Issue/Challenge/Concern Action/Mitigation
Limits of available test data Ability to adequately test data flows across interfaces Verification of EDR evaluation processes VIIRS Ocean Science Team will develop an independent simulation of the VIIRS ocean bands
Extent of prelaunch end-to-end (observatory ground system) data flows Develop/maintain system readiness for testing opportunities
ADS to PEATE interface and test planning Communication initiated, TIM planned
Complexity of IDPS internal processes and data flows impacts ability to diagnose software and algorithm problems in the ITSE Exercise in the ITSE as possible
Version synchronization of operational products with IDPS software in the ITSE Coordinate software updates with ITSE support staff
SD3E to Ocean PEATE data transfers Performance improvements being worked on both sides
IDPS file naming convention Attempt to get patch for ITSE develop workarounds for testing with SD3E