1. 1960s Nimbus Sea Ice Extent - Project Basis 1 The recent project to recover Nimbus data is an opportunity to use this 1960s data to create sea ice extent and climate data records (CDRs) for this era. A critical need in climate research is to obtain continuous high quality data records and images as far back in time as is practical for statistical significance. Early Earth-observing satellite data were not fully explored due to the limitations of historical programs and processing systems. Much of the digital data has never been seen, some of the tapes and films are either missing or deteriorating. The original engineers and researchers are now mostly in their 70s and 80s, and time is running out to contact them. Only a portion of the original 6-bit, 7 track tapes have been recovered and none has been converted to modern formats (such as HDF or NetCDF).

2. Nimbus II HRIR in Google Earth, Sept 23, 1966 THE POTENTIAL FOR DETERMINING HISTORIC SEA-ICE EXTENT FROM 1960’S NIMBUS HRIR SATELLITE DATA 2

3. Prior Work on Sea Ice with Nimbus (1972) 3 From: Nimbus satellite data for polar ice survey. J. Sissala et al, Polar Record, 1972 July 1966-15.26 10 6 km 2, 1969-16.83 10 6 km 2, 1970-17.62 10 6 km 2 2010~15.88 10 6 km 2 August 1966-15.17 10 6 km 2, 1969-17.19 10 6 km 2, 1970-18.55 10 6 km 2

4. THE POTENTIAL FOR DETERMINING HISTORIC SEA-ICE EXTENT FROM 1960’S NIMBUS HRIR SATELLITE DATA 4 1970 1969 1966 1969 1970 17.62 16.83 15.26 18.55 17.19 15.17 Nimbus Values (Sissala)

5. Chart of Polar 1960s observing satellites (August 1960-December 1969) Yellow=possible data Green=confirmed data 250+ Satellites (American & Soviet) Only 20+ with confirmed data still in existence Data Quality very high Inclination of at least 58° Recorded visible light and/or IR Sensors include- HRIR, AVCS Cosmos 243 passive microwave Months Satellites

6. Nimbus I AVCS Image September 9, 1964 6 From: Nimbus satellite data for polar ice survey. J. Sissala et al, Polar Record, 1972

7. ARGON Greenland Mosaics, 1962 & 1963 7 From: Greenland Ice Sheet Mapping using 1960s DISP Imagery. Guoqing Zhou Guoqing Zhou et al 2003

8. Other Satellite Sources 8 Meteor-Priroda (1978)Apollo 10 Image of The Arctic April 1969 AS10-34-5013 TIROS IX Image of Ross Ice Shelf January 1965

9. Other Satellite Sources 9 Meteor-Priroda (1978)Apollo 10 Image of The Arctic April 1969 AS10-34-5013 TIROS IX Image of Ross Ice Shelf January 1965