本文介绍的是印度洋偶极子，为了理解研究中的关键问题，首先认识印度洋偶极子的意义变得至关重要(Cai et al.， 2014)。这是通过印度洋赤道地区之间海面温度的差异来定义的。这些地区是西极接近阿拉伯海，东极靠近孟加拉湾。偶极子影响着亚洲东南部、澳大利亚和印度洋盆地周围其他国家的气候(Cai et al.， 2013)。印度的季风也总是受到这种现象的影响。本篇代做assignment文章由美国论文通AssignmentPass辅导网整理，供大家参考阅读。
In order to understand the key question under investigation, it becomes crucial to first acknowledge the meaning of Indian Ocean Dipole (Cai et al., 2014). This has been defined through the difference within the temperature over the sea surface between the Indian Ocean equatorial areas. These areas are western pole closer to the Arabian Sea and the east pole which lies close to the Bengal Bay. The Dipole is such that it influences the climates in areas such as South Eastern parts of Asia, the land of Australia and other nations surrounding the basin of Indian Ocean (Cai et al., 2013). The monsoon in India is also influenced invariably by this phenomenon.
Simply stated, IOD is the sea surface temperatures periodic oscillation which moves from being positive then being at neutrality and then shifting to the negative stage. When the western end sea surface temperature rises more than the normal level and results in being warm in comparison to the east side, then this leads towards IOD of positive nature (Cai et al., 2009). Such a situation has favourability for the monsoon in India as this causes a type of barrier within the east end of Indian Ocean and all the winds of southwest are responsible for blowing towards the sub-continent of India. The waters, accordingly within the eastern parts of the Indian Ocean, start cooling down. This has a tendency of causing droughts within the south eastern parts of Australia (Ummenhofer et al., 2011). On the converse, during the period of negative IOD, the tropical eastern Indian Ocean waters become warm in comparison to the Indian Ocean of tropical west. This causes enhanced rainfall over southern Australian regions.
The Indian Ocean is consistently getting warm. As per recent researches, it has been suggested that an essential part of the entire heat gain in the ocean from change in climate has found its way to the basin of Indian Ocean which has been driven through the circulation in the ocean worldwide (Ummenhofer et al., 2009). The oceans present in Australian North West region which is an essential region and source for rainfall have also run at its hottest since the previous decade. This recorded warmth has been seen across the basin since the previous 5 years. This warm water has led towards pushing enhanced moisture over to the continent of Australia along with causing an alteration to the Jetstream position.