Mutual interactions and Inter-relationships between “Weather” and “Weather Systems”

Abstract

The study relates to mutual interactions and inter-relationships between weather systems such as the Indian Ocean Dipole (IOD), Equatorial Pacific El Nino-Southern Oscillation (ENSO), Global General Circulation Patterns (GGCP), Indian South-west Monsoon (ISM), Indian North-east Monsoon (INM), and cyclones/hurricanes which deal with the wind, pressure, temperature, and rainfall. IOD has three phases, namely, positive, negative, and neutral. It relates to India and some parts including East Africa, Southern Australia, Southern China, and Indonesia. ENSO also has three phases within a 3–7-year cycle namely, warm-dry El Nino, cold-wet/rainfall La Nina, and neutral. They relate to global events. Under neutral conditions, this includes both the El Nino and La Nino conditions. In 126 years, the Indian rainfall under El Nino ranged from normal to deficit, and in the case of La Nina, it ranged from normal to surplus, and under neutral, it varied from deficit to surplus. Thus, around 50% of the occasions, it is normal. These are generalized observations, and in real situations, they might be counteracted by other weather systems. IOD and ENSO present interactions positively and negatively based on combination scenarios. GGCP covers not only global impacts but also localized impacts such as Western disturbances (WDs) in North-west India and jet stream in the USA in terms of temperature, primarily–secondarily with rainfall. WDs are a wave from the North-west Mediterranean zone – around this zone, a subtropical jet stream passes over the foothills of the Himalayan Mountains. Summer causes heat waves, and winter causes rainfall and cold waves. Cyclonic systems in the Arabian Sea and Bay of Bengal play an important role in WDs south-to-north movements of warm and cold waves in summer and winter, respectively. The jet stream in the USA causes the same way as WDs in India. It stops cold waves moving to the south in summer and allows cold wave movement to the south in winter. The jet stream is influenced by systems in the Pacific Ocean on the north-central west coast of the USA. IOD and ENSO play important roles in ISM both positively and negatively. El Nino plays a role in INM similar to La Nino on ISM. Ocean surface temperatures present cyclic patterns, for example, the Atlantic Multi-Decadal Oscillation (AMO) presented a 60-year cycle and a 132-year cycle in the South Atlantic Ocean. The same is the case with the Pacific Ocean – Pacific Decadal Oscillation (PDO) presenting a 60-year cycle in the north and a 132-year cycle in the south Pacific zones. Such cyclic variations are not given much importance while dealing the weather systems. These factors are influenced by cyclic variations in rainfall, temperatures, and cyclones in India/hurricanes in the USA over different parts of the globe, a principal component of climate change, that is beyond human control but we need to adapt to them. The Bay of Bengal cyclones followed the cyclic variation. ENSO and IOD have no systematic consistent variations.