World of Change: Antarctic Sea Ice

Introduction:

Antarctica, the southernmost icy continent, remain a paradise to the researchers for its vast ice sheet, extremely dynamic sea ice environment and above all its extreme weather and climate. Sea ice forms in both the Arctic and Antarctic polar region. Basically, sea ice is the frozen ocean water which is found in remote polar oceans. The sea ice covers nearly 25 million square kilometers of the earth on average. In Antarctica 18 million square kilometers of the sea is covered by sea-ice but during the summer only 3 million square kilometers sea-ice remain. The glaciers, icebergs, ice sheets, and ice shelves are originated on the land. Usually, sea ice grows in the winter season and melts during the summer seasons. But some part of the sea ice remains multiple years in some certain region after surviving multiple melt seasons are known as multi-year ice. Due to the remote location and extreme climate, it is difficult to study the sea ice condition. To study the movement of the sea ice, researchers have attempted several field campaigning in the polar region. In this method, the problem is that the researchers can accumulate the data in a relatively smaller region. However, remote sensing technique is useful to monitor the sea-ice considering its synoptic, repetitive and multi-spectral characteristics. Basically, remote sensing is a tool to collect the information of earth surface without any physical contact. Airborne instruments and satellite are used by the researchers to collect the data which shows the sea ice zones in the polar region, the motion of the sea ice, the temperature of sea ice and many other variables. The satellite can easily detect the sea ice in the visible, infrared and microwave region of the electromagnetic spectrum. Antarctic sea ice is crucial to the marine ecosystem as well as for the global climate. Several satellites are monitoring the sea ice since the 1970s. It is observed that sea ice around the Antartica continent slowly expanding. But from late 2016 sea ice of the Antartica is rapidly decreasing which take the interest of the climatologist as such unexpected change of the sea ice are really rare.

Objective:

Basically, sea ice may not directly affect the human species. Then why it is so important? Why does climate scientist study it? The sea ice occurs in the polar region but it influences the global climate. Sea ice contains bright white surface which returns the albedo in large scale. As a result, very few sunlight is absorbed in this region and so it remains relatively cool. But if the sea ice level is gradually decreased then very few amounts of the bright surface will be available to return back the incoming solar radiation as a result temperature of the earth will rapidly increase. Also, sea ice affects the ocean water movement. During the formation of the sea ice, most of the salt is pushed in sea water below the sea ice and also it trapped in the ice crystal in some cases. As a result of water below the sea ice has a higher concentration of salts and its density is much higher than the surrounding water and so it sinks. In this way, the sea ice contributes to the global “Conveyor belt” circulation of ocean water. The cold dense polar ocean water sinks and moves towards the equator and the hot water of the equatorial region move towards the polar region. Due to Global Warming, the Arctic sea ice and glaciers worldwide are melting gradually. But in case of Antarctica, a powerful ocean current that circles the continent, are major factors in the formation and persistence of Antarctic sea ice than changes in temperature. The Southern Ocean Circumpolar Current actually prevent the warmer sea water from entering in the Antarctican sea ice zone. However, during 2016-2018, it is observed that the sea ice is decreasing in Antarctica. In this project work, the sea-ice and associated ocean-atmospheric parameters are analyzed to understand the reason for the unprecedented decline in the Antarctic sea ice.

Methodology

First, the climate data of the Southern Ocean have to be downloaded from 1979 to 2019. From ECMWF (European Center for Medium Range Weather Forecast) Interim website, the daily climate datasets have been downloaded. Then using the CDO (Climate data operator) software in Ubuntu OS the daily mean of the data has to be calculated. After that, the climatology of the year range has to be created, to check if there is an anomaly in this year, 2019. If there is any anomaly in the Antarctic Sea ice dataset, then which climatic or oceanic parameter is influencing the most that have to find out.

Expected Result

In 2019 which anomaly is occurring in the Antarctic sea ice: Positive anomaly or Negative anomaly? Which parameter influencing most for this anomaly?

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