Nimbus Satellite Data Rescue Project for Sea Ice Extent: Preliminary results from September 1964, 1966, and 1969
Abstract
The earliest satellite data available to obtain estimates of total sea ice extent date back to 1972, based on passive microwave sensors. Earlier estimates, available from operational ice charts, provide incomplete coverage in the Arctic and virtually no coverage in the Antarctic. Recovered data from 1960s Nimbus satellite sensor now provides the potential to obtain estimates from as early as 1964. There are a number of challenges in using data from the 1960's to estimate sea ice extent. We are organizing visible and window channel infrared data from Nimbus I, II and III to attack this problem from old archive tapes (IR) and satellite based images on film (visible). There were over 7000 infrared files for just Nimbus II. We estimate there are over 200,000 images from the AVCS and IDCS from just the 1960s Nimbus missions. All this data will be recovered, scanned and rectified (Image 1). We will discuss the errors resulting from the limited spatial and temporal coverage and calibration issues using observations from the Advanced Vidicon Camera System (N1+N2), Image Dissection Camera System (N3) and the High Resolution Infrared Radiometer (HRIR) instrument onboard these early NASA satellites. The first ice detection technique involves determining the rolling minimum reflectivity over a period of 7-10 days. This effectively removes the clouds in the composite of observations from.multiple orbits. This data was then compared to the IR data covering the same period to derive an IR ice extent algorithm for the particular IR window collected by the Nimbus satellites. For the most part the IR data was collected only at night; however there were a few exceptions, which provided an opportunity for a direct temporal comparison. We will have preliminary estimates of the sea ice extent and an error estimate for 3 selected months (September 1964, 1966 and 1969) for comparison to modern ice extent measurements for both the Arctic and Antarctic. The Arctic sea ice minimums and Antarctic sea ice maximums are the beginnings of a planned monthly sea ice extent data set for 1963-1970.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.C41E0471G
- Keywords:
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- 0750 CRYOSPHERE / Sea ice;
- 1621 GLOBAL CHANGE / Cryospheric change;
- 9310 GEOGRAPHIC LOCATION / Antarctica;
- 9315 GEOGRAPHIC LOCATION / Arctic region