The untamed beauty of the Polar Regions. Image by Martin Fuchs from Pixabay
Climate change remains a pressing topic – undeniably, the consequences of climate change are far-reaching and severe, leading to more frequent natural disasters like hurricanes, droughts, wildfires and floods. This necessitates us to comprehend weather patterns, climate dynamics and the transformative impact of climate change as it is vital in trying to adapt to these changes.
We might not perceive it, but the weather in the polar regions has profound effects on our weather here in the tropics due to a phenomenon known as teleconnection. Teleconnections are defined as important links between weather events that occur in geographically distant areas – in this case, imagine a bridge in the sky that connects the climate of the Antarctic region to the mid-latitude region and finally to the tropics and vice-versa.
The research group at NARC is undertaking a study on how the sea ice extent in Antarctica in the Indian Ocean sector influences the rainfall variability during the Indian summer monsoon, a period of heavy rainfall in India occurring in the months of June through September. They used the global observation of ERA interim reanalysis to study the relationship and compare it also with the simulations of climate models under the Coupled
Model Intercomparison Project Phase 5 (CMIP5) program to study how well these climate models are able to capture the observed relationships. Understanding this connection can help in predicting and forecasting monsoon variability, which is crucial for agriculture, water resource management, and disaster preparedness in the Indian subcontinent.
The Antarctic sea ice extent (SIE) in the Indian Ocean area studied in this research
Their research not only confirms a link between Antarctic sea ice extent and the Indian summer monsoon rainfall variability via the Mascarene high which has not been studied extensively before, but has also suggested the possible mechanism for it. They discovered that changes in sea ice extent in the Indian Ocean sector affect the meridional cell circulations i.e the Polar, Ferrel and Hadley circulations. This, in turn, causes differences in rainfall patterns during the Indian summer monsoon season. This research stands out because while many studies explore how tropical climates impact polar regions, this one shifts the focus to the reverse: how climate changes in polar areas influence the tropics. Spearheading this effort to understand the science of how the weather of the polar regions affects the tropics are Dato’ Prof Azizan Abu Samah and Dr Sheeba Nettukandy Chenoli. Dato’ Prof Azizan is a professor in the field of Meteorology, while Dr Sheeba is a senior lecturer in the same field. They are both attached to the Department of Geography, Faculty of Arts and Social Sciences, Institute of Ocean and Earth Sciences (IOES) as well as the National Antarctic Research Centre (NARC).
The schematic diagram of the mechanism of teleconnection link connecting the polar regions to the tropical regions
Besides studying teleconnection between the polar regions and the tropical regions, Dato’ Prof Azizan’s group also used ERA Interim and the CMIP5 model to assess historical Antarctic precipitation and temperature trends presently and for the future. Antarctica’s precipitation is affected by different things like how the air mass advection, the shape of the land, sea surface temperature and storm activities. Understanding Antarctica’s precipitation patterns is crucial for comprehending its role in global climate systems, the potential impacts on sea level rise, and interpreting the environmental and climatic changes both within Antarctica and globally. However, measuring the precipitation in Antarctica is challenging due to its inaccessible location, making instrumental-based measurements unreliable.
Hence, researchers used all available data such as ERA interim reanalysis, and global precipitation data and compared them with the CMIP5 model to examine the trends and variability of precipitation in Antarctica. Reanalysis datasets are large collections of data that offer a thorough view of the polar regions’ historical weather and climate. However, it was found that when comparing the results obtained from the CMIP5 and the various reanalysis datasets, they do not always agree – CMIP5 models show an increasing trend in precipitation while the reanalysis datasets show insignificant changes. This study then highlights the need for caution when perusing only a single dataset, and suggests considering multiple sources for a more robust analysis.
The precipitation trend using CMIP5 models in comparison to some reanalysis datasets
from 1979 to 2005
While the Arctic and Antarctic may seem distant, climate change has shown us that what happens in these polar regions can significantly impact our tropical climate. It is crucial to recognise that studying the polar regions is not unrelated to our lives; in fact, it is essential. Understanding how weather, climate, and climate change interact between these distant poles and our tropical regions is vital in comprehending the weather patterns we experience today. These connections highlight the urgent need for further research and exploration into this complex relationship for a better understanding of our current climate and its changes and how the relatively rapid warming of the polar region can impact our region.