Progress and Ongoing Issues in the Development of a Passive Microwave Sea Ice Extent/Concentration Climate Data Record

Passive microwave sea ice products provide one of the longest continuous satellite data records with over thirty years of data. The consistent and near-complete data record is the foundation of one of the most dramatic indicators of climate change - the significant long-term decline in Arctic sea ice extent. Thus, passive microwave sea ice products are an important climate record. However, the products are currently lacking key properties to be considered true climate data records (CDRs). These include: (1) minimal metadata that does not current standards, (2) limited error statistics and a lack of grid cell or even granule- level quality assessments, (3) limited intersensor calibration periods to assure the highest consistency possible, and (4) lack of one single authoritative algorithm resulting in several different sea ice estimates. Several strategies are underway to address these deficiencies. First, improved metadata is being developed to meet current and future standards. Second, more detailed quality assessment standards are being researched. Third, more thorough intersensor calibration is being conducted, using longer overlap periods and higher quality sensors for a baseline. Finally, a variety of algorithms are being investigated, as well as data fusion methods, to obtain a single sea ice concentration/extent product that is high quality and consistent over the entire record. Collaborations are underway with U.S. and international groups, including a European project funded through EUMETSAT, to work together to produce CDR-level sea ice products and to coordinate with other cryospheric CDR efforts.