The Sea Ice Occurrence Probability (SIOP36) data were prepared from 36 years (October 1978 to December 2014) NSIDC sea ice concentration (SIC) data over the Antarctic Region (Cavalieri, 1996). The SIC data were downloaded from NSIDC data site:(http://nsidc.org/data (link is external)). The SIOP36 data consist of 366 data files corresponding to 366 days with the first file representing 1st January and the last, 31st December. The file naming nomenclature follows SIOP36_MMDD_S.bin[.tif/.png] format; where MM refers to month number (01 to 12, 01 being January), DD refers to date of the month, and the character S refers to Southern Hemishphere.
Data formats are indicated by .bin (Binary), .tif (GeoTIFF), and .png (Portable Network Graphics). Data is freely available to global scientific community and can be downloaded from www.mosdac.gov.in (link is external). Probability values are calculated from the long-term NASA Team algorithm-derived SMMR-SSM/I-SSMIS sea ice concentration product (Cavalieri, 1996). The dataset is given in Polar Stereographic projection with a grid size of 25km x 25km in latitude and longitude. The grid coordinates of the upper left pixel are 39.2 deg S, 42.2 deg W. There are 316 columns and 332 rows. Data values are stored as IEEE floats representing probabilities in the range 0-100%. Pixels with zero values corresponds to either Antarctic land/ice or ocean water.
Data Access
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Data Version
- SIOP36 (ver BETA)
Data Sources
- The major input data is NASA Team algorithm-derived SMMR-SSM/I-SSMIS sea ice concentration data over Antarctic Region (Cavalieri, 1996) for 36 years (October 1978 to December 2014). The data was downloaded from NSIDC data site: (http://nsidc.org/data).
Processing Steps
- Following are the three major processing steps :
- i. Classification of pixels into sea-ice and non-sea-ice classes.
- ii. Determination of sea-ice-pixel frequency over study period
- iii. Calculation of Sea Ice Probability
- iv. Converting the data into three (.bin, .tif, and .png) formats.
Data Citation
- Data Citation
- This dataset may be cited as (Rajak et al, 2015). Rajak D. Ram, R.K. Kamaljit Singh, Jayaprasad P., Sandip R. Oza, Rashmi Sharma, and Raj Kumar (2015). Sea Ice Occurrence Probability Data and Its Applications Over the Antarctic. Manuscript submitted to a journal.
References
Cavalieri, D. J., C. L. Parkinson, P. Gloersen, and H. Zwally. 1996, updated yearly. Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data. [October 1978 to December 2012]. Boulder, Colorado USA: NASA National Snow and Ice Data CentreDistributed Active Archive Centre.
References
- This dataset may be cited as (Rajak et al, 2015).
- Comiso, J. C. 2000, updated 2014. Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS. Version 2. [October 1978 to December 2012]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.
- Rajak D. Ram, R.K. Kamaljit Singh, Jayaprasad P., Sandip R. Oza, Rashmi Sharma, and Raj Kumar (2015). PROBABILISTIC SEA ICE OCCURRENCE DATA OVER ANTARCTIC REGION. Manuscript under preparation.
Derivation Techniques and Algorithm
- Daily Probability of occurrence of sea ice: Pr = 100 x N / (Y-n)
- where,
- N, is the number of times the pixel has been classified as sea ice (sea ice concentration => 15%);
- Y, is the total possible observations, and
- n is the number of years with data loss on that particular date.
Limitations
- Accuracy assessment of the dataset has not been carried out.
Known problems with data
- The inherent problems of the major input sea ice concentration data (from NSIDC site) may be considered the problems with this dataset.
Related data collections
- Northern Hemisphere EASE-Grid 2.0 Weekly Snow Cover and Sea Ice Extent. Version 4. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center (Brodzik, M. and R. Armstrong. 2013.). [http://nsidc.org/data ].
File Naming Convention
- The file names follows SIOP36_MMDD_S.bin[.tif/.png] naming convention;
- Where
- MM refers to month number (01 to 12, 01 being January),
- DD refers to date of the month, and
- S refers to Southern Hemisphere.
- Data types are indicated by .bin (binary), .tif (geotiff), and .png (portable network graphics).
MetaData
| Sr. No | Core Metadata Elements | Definition |
| 1 | Metadata language | English |
| 2 | Metadata Contact | D. Ram Rajak, OSD/AOSG/EPSA, Space Applications Centre (ISRO), Ahmedabad-380015, India. Email: rajakdr@sac.isro.gov.in |
| 3 | Metadata date | March 05, 2015 |
| 4 | Data Lineage or Quality | First ever sea ice occurrence probability data available over the Antarctic |
| 5 | Title | Sea Ice Occurrence Probability Data over the Antarctic (SIOP36). |
| 6 | Abstract | Antarctic Sea Ice Occurrence Probability (SIOP) for each day from January 1st to December 31st is generated from NSIDC sea ice concentration data (Comiso, 2000) which were downloaded from the NSIDC site: (http://nsidc.org/data). The SIOP data for 36 years (October 1978 to December 2014) are named as SIOP36 |
| 7 | Dataset Contact | D. Ram Rajak, OSD/AOSG/EPSA, SAC (ISRO), Ahmedabad-380015, India. Ph: +91 79 2691 6051. Email: rajakdr@sac.isro.gov.in |
| 8 | Update frequency | 3 years |
| 9 | Access Rights or Restriction | Open Access |
| 10 | Spatial Resolution | 25 000 m |
| 11 | Language | English |
| 12 | Topic Category | Polar Science |
| 13 | Keywords | Sea Ice, Probability, the Antarctic |
| 14 | Date or period | January 01 to December 31 Sea Ice Occurrence Daily Probability calculated from October 1978 to December 2014 data |
| 15 | Responsible Party | D. Ram Rajak, R. K. Kamaljit Singh, Jayaprasad P., Sandip R. Oza, Rashmi Sharma, and Raj Kumar, Space Applications Centre (ISRO), Ahmedabad-380015, India |
| 16 | Organization | Space Applications Centre (ISRO), Ahmedabad, India |
| 16a | Org. role | Calculated Sea Ice Occurrence Probability (SIOP) for each day from January 1st to December 31st using NSIDC sea ice concentration data (Comiso, 2000). Further details are available in Rajak et al, 2015 |
| 16b | Individual name | D. Ram Rajak, OSD/AOSG/EPSA, SAC (ISRO), Ahmedabad-380015, India. Ph: +91 79 2691 6051. Email: rajakdr@sac.isro.gov.in |
| 16c | Position | Scientist/Engineer, OSD/AOSG/EPSA, SAC (ISRO), Ahmedabad-380015, India. Ph: +91 79 2691 6051. Email: rajakdr@sac.isro.gov.in |
| 16d | Vertical Extent (minimumValue, maximumValue, unitOfMeasure, vertical datum) | Probability in percentage. Minimum value = 0.0294%. Maximum value = 100.0%. Mask: Antarctica land/ice and open ocean water (value = 0.0) |
| 17 | Geographic Extent | UL Coordinates: 40S, 42W. UR Coordinates: 40S, 42E. LL Coordinates: 42S, 135W. LR Coordinates: 42S, 135E |
| 18 | Geographic name, geographic Identifier | Ocean surrounding Antarctica |
| 19 | Bounding box | UL Coordinates: 40S, 42W. UR Coordinates: 40S, 42E. LL Coordinates: 42S, 135W. LR Coordinates: 42S, 135E. Number of columns i. e. image width: 316 pixels. Number of Rows i.e. Image Height: 332 pixels |
| 20 | Temporal Extent | Based on input NSIDC Sea Ice Concentration Data October 1978 to December 2014 |
| 21 | Access Rights or Restrictions | Open Access |
| 22 | Distribution Information | Online download in Binary, GeoTIFF and PNG formats. Binary and GeoTIFF data in Float format |
| 23 | Processing Level | Level 4 (Data product derived from sea ice concentration product) |
| 24 | Reference System | Projection: Polar Stereographic (0.0 E,70.0 S,0.0 m,0.0 m). Datum: WGS84 |
