# Presentation: 854136

## National Ice Center research activities

- Kim Partington and Cheryl Bertoia

**National Ice Center research activities**

- National Ice Center

- 18 December 1997

## Contents of talk

- Context of science activities
- Research and development status
- SAR
- SSM/I
- Understanding SSM/I data
- Algorithm evaluation
- A new SSM/I algorithm based on data fusion
- New science plans

- National Ice Center

- 18 December 1997

## NIC Science Plan:context for the program

- * on http://www.natice.noaa.gov

- NIC Science Plan*

- Customer Survey
- (completed April 98)

- NIC 5 year plan (completed November 97)

- Sponsor priorities
- (ONR, NOAA,
- NASA, NIC)

- Anticipated operational sensors

- Resources

- National Ice Center

- 18 December 1997

## Planned product evolution:NIC 5 year plan

- Moving towards:-

- FUTURE REGIONAL PRODUCT

- CURRENT GLOBAL PRODUCT

- daily

- non-global

- manual, some automation

- high resolution (<1km)

- global

- model / assimilation-based

- low resolution (10 km)

- FUTURE GLOBAL PRODUCT

- daily

- weekly

- global

- manual

- National Ice Center

- 18 December 1997

## NIC 5 year product plan

- A key to achievement of this plan depends on making progress in the use of key data sources
- The science program aims to address this through focussing efforts on key data sets
- SSM/I
- RADARSAT/ENVISAT
- MODIS

- National Ice Center

- 18 December 1997

## NIC Research priorities

- SAR: RADARSAT I, II and ENVISAT
- invaluable, but difficult to interpret at times
- SSM/I
- weak component in quality of ice charts, but important for reasons of coverage
- fundamental to the success of the ice forecasts
- MODIS
- high potential, uncertain algorithm performance

- National Ice Center

- 18 December 1997

## SARResearch and Development

- Cheryl Bertoia (NIC)
- Costas Tsatsoulis, LeenKiat Soh (Univ. Kansas)
- Florence Fetterer (Univ. Colorado)
- Adnan Trakic and Kim Partington (NIC)
- Denise Gineris (ERIM)

- National Ice Center

- 18 December 1997

## Automated SAR techniques

- Multiyear Ice Mapping System
- Florence Fetterer, NSIDC
- Thin Ice System: ARKTOS
- Costas Tsatsoulis, KU
- Algorithm evaluation and testing
- Denise Gineris, ERIM (on site)

- National Ice Center

- 18 December 1997

## Radar tools

- Radarsat

- Radarsat

- Batch tools

- Ice classification

**Current Situation**

**Future Situation**

- National Ice Center

- 18 December 1997

## MIMS

- MIMS - Multi-year ice mapping system
- Developed by Fetterer et al., Univ. Colorado
***Objective:*** To quickly map all the old ice in uncalibrated Radarsat ScanSAR imagery
***Output:*** Color-coded map of multi-year ice, multi-year concentration contour map
***Status:*** Delivered to NRL Fall 98, testing, incorporation into new analysis system ->2000

- National Ice Center

- 18 December 1997

## ARKTOS

- Intelligent system that combines image processing and AI to type sea ice
- Modular, integrated suite of tools
- Java GUI for viewing system outputs
- Easy editing of knowledge and all system parameters while in test mode

- National Ice Center

- 18 December 1997

## ARKTOSCurrent Implementation

- ARKTOSCurrent Implementation

- National Ice Center

- 18 December 1997

## ARKTOS: Image Processing

- 5 x 5 Gaussian averaging
- Image segmentation: Watershed with merging to generate reasonable objects from a given sea ice image: Turn pixels into *objects*
- Feature extraction: Compute properties of each object (e.g. area, roundness, elongation)
- Facts: Use features as data for generating *facts; *D-S needs facts, not numerical data

- National Ice Center

- 18 December 1997

## Dempster-Shafer Classifier

- Uses multiple rule bases (winter, summer)
- Generates a dominant classification for individual ice features
- Belief shows how much evidence supports the hypothesis
- Plausibility- how plausible, despite evidence to the contrary
- Evidential interval is bounded by Belief and Plausibility

- National Ice Center

- 18 December 1997

## ARKTOS:The Rules

- March 1998: 95 rules gathered using knowledge engineering techniques:

*G: Sort of looks like a big piece of old ice on top there*
*T: OK. Let’s call that A. Why is it because of?*
*G: Again, because of a smooth rounded edge with still a *
*    **type of mottled texture inside it. Sort of a darker gray*
*    **picture. I would say that is all old ice.”*
- (ERSBF 140695a; 71N, 127W; June 14)

- National Ice Center

- 18 December 1997

## ARKTOS

- SCW image

- Segmented image

- Classified image

- National Ice Center

- 18 December 1997

## ARKTOS:The Future

- Improve and test SSM/I implementation
- Test NT version
- Goal: NIC transition to operations floor by April, 1999
- Subsequent work: add climatology and NIC ice chart ancillary information, expand to new geographic regions, modify for ENVISAT

- National Ice Center

- 18 December 1997

## SSM/Iresearch and development

- 1. Understanding SSM/I data using PCA analysis
- 2. Evaluating SSM/I algorithms
- 3. A new SSM/I algorithm based on data fusion

- National Ice Center

- 18 December 1997

## Analysis of SSM/I data using principal components analysis

- Observations from controlled experiments

- Normalized values

- National Ice Center

- 18 December 1997

## PCA analysis: summary of information content

- National Ice Center

- 18 December 1997

## Principal component 3:areas of new ice production

- Principal component 3:areas of new ice production

**Information on thin ice types is contained in lower variance principal components**

- National Ice Center

- 18 December 1997

## Understanding SSM/I:preliminary conclusions

- New ice and snow depth are significant to the third and fourth principal components, but first two components are relatively insensitive to these conditions
- Young ice and snow-free first-year ice are radiometrically similar to all channels
- Like SAR, SSM/I is sensitive to the very early stages of new ice growth
- Principal components could be used in an SSM/I algorithm for thin ice detection

- National Ice Center

- 18 December 1997

## 3. SSM/I algorithm evaluation

- Work carried out by Kim Partington and Cheryl Bertoia

- National Ice Center

- 18 December 1997

## SSM/I algorithm evaluation

- NIC requested FNMOC to implement the NASA Team algorithm to compare against the CAL/VAL algorithm
- An evaluation was undertaken and results presented to the SSM/I Algorithm Research Panel in January 1999.
- The evaluation has been extended to include other algorithms implemented at NIC

- National Ice Center

- 18 December 1997

## Arctic C/V - NT difference map9 December 1998

**NASA Team**
**> CALVAL**

- -5 to 0%

- -10 to -5%

- -15 to -10%

- <-30%

- -20 to -30%

- -20 to -15%

- +5 to 0%

- +10 to +5%

- +15 to + 10%

- >+30%

- + 20 to + 30%

- + 20 to + 15%

**CALVAL >**
**NASA Team**

- No difference

- National Ice Center

- 18 December 1997

## CV - NT differencesby Arctic region

- (samples are partial “rectangular” segments of regions, so
- these numbers are not statistically rigorous)

- National Ice Center

- 18 December 1997

## Antarctic C/V - NT difference map9 December 1998

**NASA Team**
**> CALVAL**

- -5 to 0%

- -10 to -5%

- -15 to -10%

- <-30%

- -20 to -30%

- -20 to -15%

- +5 to 0%

- +10 to +5%

- +15 to + 10%

- >+30%

- + 20 to + 30%

- + 20 to + 15%

**NASA Team**
**< CALVAL**

- National Ice Center

- 18 December 1997

## CV - NT differencesby Antarctic region

- (samples are partial “rectangular” segments of regions, so
- these numbers are not statistically rigorous)

- National Ice Center

- 18 December 1997

## CV - NT ice edge difference

- Ice edge differences season and hemisphere-independent
- Resolution effect

- *EFOV difference between 19 and 37 G.Hz. 25 km to 32 km

- National Ice Center

- 18 December 1997

## Results of CV-NT algorithm evaluation

- CAL VAL appears more accurate than NASA Team in predicting total ice concentration and edge position
- FNMOC to continue CAL/VAL as primary data stream
- Recommendations to:
- maintain NASA Team as secondary data stream in north and Bootstrap in south
- consider adding 85GHz ice tracker as routine product to assist with ice analysis and eventual assimilation into PIPS

- National Ice Center

- 18 December 1997

## Additional algorithm survey

- Additional algorithms have been implemented for testing at NIC:
- Bootstrap
- Bristol Hybrid
- NASA Team for thin ice
- NASA Team 2 (with radiative transfer modeling)

- National Ice Center

- 18 December 1997

## General algorithm survey:Sea of Okhotsk, 9 December 1998

- General algorithm survey:Sea of Okhotsk, 9 December 1998

- National Ice Center

- 18 December 1997

## General algorithm survey:Greenland Sea, 9 December 1998

- General algorithm survey:Greenland Sea, 9 December 1998

- National Ice Center

- 18 December 1997

## SSM/I algorithm sensitivityto ice types

- In situ passive microwave measurements from different ice types

- Apparent ice
- concentration

- National Ice Center

- 18 December 1997

## Algorithm difference is relatedto thin ice concentration

- C/V - NT
- concentration
- difference

- Partial concentration of new+young ice from NIC ice charts
- for areas that are >=9/10 total ice concentration

- National Ice Center

- 18 December 1997

## Evidence for source of algorithm differencefrom PCA

- C/V - NT difference

- PC 3

- PC 3 detects new ice
- vs. water and other ice

- National Ice Center

- 18 December 1997

## Multi-year ice mapping with SSM/I

**MYI concentration**

- 100%

- 85%

- 25%

- 45%

- 65%

- 10%

- 0%

**80% multi**
**year ice**
**contour**

**SSM/I NASA Team**

**9 Nov 1996**

**RADARSAT manual analysis**

- National Ice Center

- 18 December 1997

## SSM/I algorithm evaluation: summary

- NASA Team, Bootstrap and Bristol Hybrid algorithms fail to detect some types of thin ice.
- NASA Team algorithm modified for thin ice works well in Sea of Okhotsk and would be a good candidate in areas of no multi-year ice.
- NASA Team 2 algorithm has similarities with the CAL/VAL algorithm in results but not method.  Both saturate over large areas, but appear good at detecting ice.
- Multi-year ice mapping is too poor to be operationally reliable at present with NASA Team or CAL/VAL algorithms.

- National Ice Center

- 18 December 1997

## 4. A new SSM/I algorithm based on data fusion

- Work carried out by Kim Partington, Mary Keller,
- Adnan Trakic and Kyle Dedrick (NIC)

- National Ice Center

- 18 December 1997

## SSM/I Interpolation (SI) algorithm

- Conventional algorithms contain geographic and temporal biases resulting from global tie-points
- A database is impractical because each year varies
- Our evaluation shows that, even with tuned tiepoints, the algorithms contain biases (e.g. failure to detect new ice)
- On a weekly basis, high quality information on ice conditions exists in parts of ice charts derived from RADARSAT and cloud-free OLS and AVHRR data
- Therefore, these data can be used to automatically tune an SSM/I ice algorithm on a weekly and regional basis and then used to interpolate ice concentrations where no SAR or cloud-free data exists

- National Ice Center

- 18 December 1997

## Existing Ice analysis procedure

- DMSP OLS 2 GB/day

-  AVHRR 2 GB/day

- RADARSAT 0.8 GB/day

- DMSP SSM/I

**New NIC chart**

- PIPS forecast model

- NIC chart - previous week

- weather

- Analysis

- Analysis

- Analysis

- Climatology

- Analysis

- Analysis / QA

- National Ice Center

- 18 December 1997

## Proposed new ice analysis procedure

- DMSP OLS 2 GB/day

-  AVHRR 2 GB/day

- RADARSAT 0.8 GB/day

- DMSP SSM/I

**New NIC chart**

- PIPS forecast model

- NIC chart - previous week

- weather

- Analysis

- Analysis

- Analysis

- Climatology

- SI Algorithm

- Analysis / QA

- SSM/I data

- “Partial” ice chart

- SI Algorithm output

- National Ice Center

- 18 December 1997

## New algorithm: partial andcomplete ice charts

- No SAR, reconnaissance, AVHRR, OLS

- Beaufort Sea, 17 August 1998

- National Ice Center

- 18 December 1997

## SI algorithm

- SSM/I brightness temperatures

- SSM/I attribute calculations, for CT = (Aidi) for i=0,7
- 	d0=1
- 	d1= PC 3
- 	d2= PC 4
- 	d3= PC 5
- 	d4-5= NASA Team partial concentrations
- 	d6-7= Bootstrap partial concentrations

- Iterative, linear least squares fit to generate Ai coefficients

- Interpolation of ice concentration CT over “no data” area of partial ice chart

- Partial ice chart concentrations

- National Ice Center

- 18 December 1997

## SI and conventional algorithms:Barents Sea

- SI and conventional algorithms:Barents Sea

- 16 November 1998

- National Ice Center

- 18 December 1997

## SI and conventional algorithms:Barents Sea

- SI and conventional algorithms:Barents Sea

- 14 December 1998

- National Ice Center

- 18 December 1997

## SI vs. conventional algorithm performance

**Mean difference between partial ice chart and algorithm estimates**

- Barents Sea

- Ice chart -
- algorithm
- concentration
- difference

- date

- National Ice Center

- 18 December 1997

## SI vs. conventional algorithm performance

- |Ice chart - algorithm|

- Date

**Mean absolute ice concentration difference for regional ice chart area**

- Barents Sea

- National Ice Center

- 18 December 1997

## Percentage of variation explained bydifferent components of the SI algorithm

- This pie chart shows how much of the predicted ice concentration is associated
- with each group of attributes that go into the algorithm

- National Ice Center

- 18 December 1997

## SI algorithm status

- Algorithm has been implemented and works correctly. Partial and complete ice charts have been generated in raster format.
- Analysis to be completed for Barents Sea and carried out on Bellinghausen Sea, for period Nov. 98 - Jan. 99.
- If successful, operational implementation will be planned

- National Ice Center

- 18 December 1997

## Planned research activities

**NIC Post-docs**
- Walt Meier - SSM/I algorithms and data assimilation - collaboration with Jim Maslanik and Soren Andersen, DMI
- Tony Beesley -  theoretical distribution of ice thickness and improved seasonal forecasts in Alaska and Baffin Bay sectors - collaboration with John Walsh
**PIPS 3.0 program**
- model developments, funded by ONR
- TBD data assimilation, of satellite / buoy drift vectors and improved SSM/I concentrations
**PCA Analysis of NOW ship-borne radiometer data**
- collaboration with Ken Asmus and David Barber
**ENVISAT dual polarization products**
- ESA accepted project with CIS and USCG, led by JPL
**MODIS algorithm evaluation and development**
- student project led by Jim Maslanik and Koni Steffen, also involving NPS, Monterey

- National Ice Center

- 18 December 1997