"Why was the Weddell polynya present in the 1970s, and then absent until its recent reappearance?" Experts believe that the Weddell polynya might a part of some cyclical process but they lack clear details.
The opening is called a polynya, a term that defines open water surrounded by ice.
Scientists first reported about its existence in the early '70s, and during that time it opened up for three consecutive winters.
Researchers, including a group at the GEOMAR Helmholtz Center for Ocean Research Kiel, have been closely monitoring the polynya since it first reappeared in the satellite data. This nearly twice the size of the Netherlands and marginally smaller than Ireland. According to NASA, that sinking water contributes to the cold water mass, known as Antarctic Bottom Water, which feeds into deep ocean currents and contributes to ocean circulation around the globe. "On-site measurements in the Southern Ocean still require enormous efforts, so they are quite limited".
Professor Mojib Latif explained to Phys.org that this process leads to extra heat being released to the atmosphere for several winters in a row until the heat reservoir reaches the highest levels.
Simulated temperature development in the area of the polynya is illustrated above. Due to higher precipitation levels in the region and melting ice, the surface is expected to decouple from deeper water layers.
Right now, why the hole opened again is a mystery.
Blaming climate change for this giant hole is one alternative that the scientists have but according to Moore, that would be a premature thing.
"Global warming is not a linear process and happens on top of internal variability inherent to the climate system. We don't really understand the long-term impacts this polynya will have".
As scientists continue to hone their climate models and ideal their predictions, they're getting closer to being able to accurately simulate the exact process at work, but a full explanation may still be years away.