Determining 1960'S Sea-Ice Extent from Early NIMBUS Satellite Data
Abstract
There is a wealth of early Earth-observing satellite data that were never fully explored due to the limitations of historical programs and processing systems. The data was generally of high quality but the output from the early computers was marginal by today’s standards. With the recent recovery of some of these data, there is now an opportunity to use this 1960’s vintage data to create sea ice extent climate data records (CDRs) for this era. Climate researchers need quality data records as far back in time as is practical. This project aims to address that need by pushing back the beginning the satellite based sea ice extent by nearly 17 years from the current CDRs. Satellites containing visible and infrared imaging instruments for weather or climate purposes begin in the early 1960’s. NASA started this effort with the TIROS and Nimbus series of spacecraft. The early Nimbus research satellites were the first to be launched into orbit with a high enough inclination to provide complete polar coverage. Nimbus carried 3 experimental sensors, the HRIR (High Resolution Infrared Radiometer), the MRIR 5 band Medium Resolution Infrared Radiometer and the AVCS (Advanced Video Camera System). The HRIR instrument had a ground resolution of 8 km. The data must be spatial corrected and select processing artifacts must be corrected. This presentation will display the initial global results. The objective of this project is to generate monthly (or better) sea-ice extent CDRs for the time intervals covered by NIMBUS I, II and III and TIROS 9&10. Prior Nimbus analysis by J. Sissala (1972) determined the Antarctic sea Ice extent for 2 discrete months in 1966, 1969 and 1970 from Nimbus AVCS and HRIR data. Their data indicates that the 1960s may have had higher sea ice variability then the existing 30-year record. This new project will reexamine this earlier work and will develop a multi-step process to define and build the new CDRs. The initial step is the reprocessing and correcting of all the available HRIR data. The available MRIR data, AVCS and TIROS visible band video images (film) will be acquired to help in the analysis. Next, techniques must be developed to determine the monthly average sea-ice extent from these data. We expect clouds will be the most difficult challenge in the process. Finally, the standards for these 1960s CDRs must be published along with the resultant data. Nimbus II 9/23/66 HRIR
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.C21D..07G
- Keywords:
-
- 0750 CRYOSPHERE / Sea ice;
- 0758 CRYOSPHERE / Remote sensing;
- 1621 GLOBAL CHANGE / Cryospheric change;
- 1912 INFORMATICS / Data management;
- preservation;
- rescue