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Monitoring the Arctic and Antarctic By: Amanda Kamenitz.

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Presentation on theme: "Monitoring the Arctic and Antarctic By: Amanda Kamenitz."— Presentation transcript:

1 Monitoring the Arctic and Antarctic By: Amanda Kamenitz

2 Introduction Differences between Antarctic and Arctic Satellites used to help monitor the ice content for both What these tools are used for Distinguishing between all of the different types of ice in both polar regions Conclusions in the changes that occur over the years since satellite help

3 Arctic Ocean Covered mostly by sea (2-3 meters thick) High Albedo Acts as a an energy sink for the Earth The ocean span is 14 million km squared Winter weather: darkness, cold and stable Summer Weather: daylight, foggy, weak cyclones

4 Arctic contd. Central surface covered by a perennial drifting polar ice Ice pack surrounded by open seas over the summer Landmass doubles the size in the winter

5 Antarctic Antarctic Ice sheet makes up 98% of Antarctica 14 million squared kilometers 30 million cubic km of ice 61% of Earth’s fresh water East Antarctica rests on major land mass West Antarctica can extend to 2,500 meters below sea leavel

6 Satellites Used Passive and active microwave sensors (SAR) – SSM/I (launched in 1987) – EOS AMSR-E (launched in May 2002) Sonars Radiometers – AVHRR Infrared Sensors Polar Orbiting – Landsat – Nimbus

7 Differences in Monitoring Arctic and Antarctic Microwave radiance differences Ice tie points First Year Ice type A Multiyear Ice type B For Antarctic distinguishing between A and B is lost Emissivity differences Snow cover on top of ice mimics the microwave signature of Multi year ice

8 SSM/I Sea Ice concentration maps (1988-2001) derived from the sea brightness temperatures Data extracted from ERS satellite imagery to find multiyear sea ice compounds For January across these years revealed persistent coverage in central Arctic surrounded by fluctuating interannual cover During 1988-2001 net January ice declined at a rate of -54.3 x 10^3 km^2 per year. Biggest decline in Chukchi and Beaufort Seas In Fall 06 an increase in content of 10^5 km helped replenish the last 8 year decline Arctic Oscillation also effects the ice content


10 AVHRR Derives monthly monthly temperatures for the Arctic Surface temperatures at latitudes higher then 60̊ (1981-2003) increased on average ½ degree Celsius per decade Warming trends vary with season also (Winters in Eurasia produce more cooling) Net warming shows that there a few more days of warming rather then cooling Limited area can underestimate the warming in certain areas

11 AMSR-E (Advanced Microwave Scanning Radiometer Observing System) High spatial resolution (5-50 km), twice the resolution then any before Wide range of frequencies More accurate for measuring sea ice content Six different frequencies (horizontal and vertical polarizations) Sea ice content observed at National Snow and Ice Data Center

12 AMSRE (Aqua Satellite) Maximum sea ice of 2008 on March 9 th False color in image derived from 6.25 km 89 GHz brightness Sea ice extent derived from AMSRE 12.5 km sea ice concentration

13 Landsat and Nimbus Optical passive systems Measure radiation from Earth’s surface and atmosphere Nimbus-7 (launched 1978) – Swath width 185 km – Brightness temperature (Kelvin) – Spatial resolution 25 km Landsat-7 (images acquired March 2003) – Variety of sea ice conditions and concentrations – Measures radiation in visible and near IR – Images of Bering and Chukchi Seas – Converts Spectral Radiance to planetary reflectance by :ρp=∏*Lλ*d^2*ESun λ*cosθs

14 Landsat-7

15 Sea Ice Concentration with Landsat-7

16 Nimbus 7

17 Distinguishing the Arctic Albedo Atmospheric effects Spectral reflectance and Snow density (.38-1.20 micrometers)

18 Contd. Optical & Microwave Remote Sensing Emissive mode inadequate for detecting glaciers

19 NASA’s studies on Ice Concentration for Arctic and Antarctic 30 Year span of satellite imagery N. Hemisphere Arctic melting S. Hemisphere Antarctic increasing over the past few years (dramatic decrease from 1973-1977) Recently Arctic losing ice at a faster rate Comparing Arctic for the past 2 decades to past 3 decades there’s a 20% faster decreasing rate 1972-2002 Arctic has decreased the size of Arizona (300,000 square km of loss per decade) The Antarctic increase is not enough to make up for previous losses 1972-2002 Antarctic decreasing 150,000 square km per decade Recent Antarctic increase may be due to long term atmospheric oscillations bringing stronger westerly winds and cooler temperatures

20 Arctic Ice change (NOAA’s Climactic Data Center)

21 References 16173.html Arctic and Antarctic Sea Ice Marching to Different Drivers 16173.html cap.php View from Above: Satellite Monitoring o the Arctic Ice Cap cap.php Special Sensor Microwave Imager (SSM/I) Sensor Document &arnumber=1717697 Assessment of EOS Aqua AMSR-E Arctic Sea Ice Concentrations Using Landsat-7 and Airborne Microwave Imagery. &arnumber=1717697 Satellite Observed Changes in the Arctic. Physics Today NASA Team Sea Ice Algorithm. Donald J. Cavalieri

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