Essay Example on Atmospheric States of the World: The North Atlantic Oscillation

Every place in the world has an atmospheric state that corresponds to a specific location and time. One should note that it all depends on cloudiness, heat, wind, rain, and sunshine. For instance, the North Atlantic Oscillation portrays a weather phenomenon that occurs within the North Atlantic Ocean. Here, the weather depicts the atmospheric pressure differences and fluctuations between the Azores high and Icelandic low. These fluctuations determine the direction and force of westerly winds. In turn, meteorologists can then predict where storms will occur within the North Atlantic areas in the world.

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However, aspects such as climate variability have had a significant impact on the North Atlantic Ocean over the past years. For instance, some places can be deemed cooler or warmer than average conditions. As of today, global warming has made the Arctic ocean to be in a warming phase that causes the melting of large chunks of ice sheets. Therefore, this means that the North Atlantic Oscillation differences can change the climate and influence the ecosystem depending on the atmospheric pressure of specific locations.

Typically, the NAO depicts atmospheric winter variability on the Northern part of the Atlantic. During winter, extra-tropical areas are significantly affected depending on the NAO phase. Meteorologists use the Standard NAO Index, which entails a mathematical description, to define both the negative and positive phases of the NAO (Boström 2). They calculate the NAO index to display the temperature anomalies across the subtropical high and subpolar low. Typically, it is often determined by calculating the differences between the anomalies found on the surface pressure.

A Positive NAO phase depicts that both the subtropical high and the subpolar low pressures are higher than the normal readings. During this phase, the rise in the pressure difference between these regions makes the storm track to shift northward while also strengthening the Atlantic jet stream (Dahlman). The northern part of Europe often receives more precipitation and experience warmer temperatures than the average. An increase in temperatures is linked to the large air masses coming from lower latitudes. On the other hand, the southern part of Europe receives lower than the rate of precipitation with minimal storms. Consequentially, the eastern part of North America experiences low storms because of high air pressure.

On the contrary, the Negative NAO phase represents a situation where the subtropical high and the subpolar low pressures are lesser than the normal readings. In this case, the subtropical high and subpolar low pressures are weak, reducing the atmospheric pressure all over the Northern Atlantic region. In turn, the region experiences less than average precipitation and decreased storminess (Dahlman). Moreover, the southern part of Europe faces high precipitation, increased storms, and warmer temperatures. The Eastern part of North America faces increased storms, which is brought by low air pressure.

Significant changes in the amplitude and frequency of climate that are caused by NAO can have a profound effect on the ecosystem. For instance, it can be the abundance of certain species, the pattern of population, or even the ecological process (Hurrell et al. 232). Differences in the spatial patterns can harm a nation by affecting international agreements such as fishery benefits. When determining the effect of climate on the ecological system, researchers often focus on snow depth, precipitation, and temperature. It is crucial to use the indices of several climate modes when measuring the weather. The primary reason is that they can be linked to the physical variability of a system. Nevertheless, it is important to note that certain NAO impacts depend on data regarding the atmospheric circulation pattern.

The differences in the mean circulation patterns brought about by NAO is often accompanied with variations the intensity, path, and several storms (Hurrell et al. 240). When winter approaches, the storm track links both the North Atlantic and North Pacific basins. Here, these places experience maximum storms. Determining the changes in storminess strongly depends on the method of analysis and whether if the meteorologist focuses on the upper-air features. The positive NAO index depicts a shift of storm activity to the northeast while the southern part faces a decrease in activity (Riaz et al. 1). For example, in the 1990s, index winters corresponded with an increase in wave heights on the north-eastern part of Atlantic and a decrease of waves in the south. Thus, this had an effect on offshore industries, ship operations as well as the regional ecology.

What is more striking is that the changes in storminess in the NAO index are also portrayed by the movement and overlapping of the atmospheric pressure (Hurrell et al. 240). Therefore, this affects the dissemination of precipitation and evaporation. In winter, when the NAO index is high, more evaporation is experienced in the Canadian Arctic and Greenland, which exceeds precipitation. Dry conditions are experienced in some parts of the middle east and southern Europe, whereas there is much precipitation in regions such as Iceland.

Observations made on the subsurface ocean portray climate variability for a long period. The primary reason is due to the month-to-month variations on atmospheric circulations. One ought to know that the atmospheric circulation decreases with an increase in depth (Hurrell et al. 241). However, taking these measurements is hard in contrast to surface observations. Nevertheless, the atmospheric circulation of the North Atlantic shows that there are fluctuations that correspond to the low NAO index.

The oceanic MLD (mixed-layer depth) is affected by the oceanic and atmospheric conditions brought by NAO. Typically, the MLD is a crucial factor that influences marine productivity (Hurrell et al. 242). It often determines both nutrient concentration and light intensity reaching living organisms such as phytoplankton. Aspects such as heat exchange and the vertical mixing of winds influence the MLD. Therefore, this means that the winter NAO is responsible for temperature anomalies in the ocean, which extend to base.

There is a relationship that exists between sea ice reduction and the negative shift of the NAO index (Caian et al. 242). Over the past decades, ice edges have melted in the Arctic region even in winters that portray weaker atmospheric circulation anomalies. Earlier experiments depict that the reduction of ice in the Arctic region resulted from warm temperatures in higher latitudes and is connected to low western winds. However, when the NAO index trend is positive, the sea ice boundary in the Labrador Sea extends to the sound, whereas the Greenland ice boundary extends to the north. The atmosphere is responsible for the sea ice anomalies due to wind-driven anomalies or through temperature anomalies found on the surface air.

Moreover, the positive NAO period has a significant impact on the seawater salinity in places located outside Canada (Boström 10). For instance, an increase in sea ice means that the salinity water will be higher than the average. It also affects thermohaline circulation because of the differences in the salinity of seawater and the temperature. When the sea ice extends, more cool water is formed, thereby influencing the formation of deep waters. In turn, this blocks thermohaline circulation.

Conclusion

In conclusion, the North Atlantic Oscillation differences can have a significant influence on the climate and the ecosystem. Meteorologists often determine the NAO index to portray the temperature anomalies across the Azores high and Icelandic low. During the positive NAO period, there is a rise in the pressure difference between the two regions, making the storm track to move northwards and also strengthen the Atlantic jet stream. On the other hand, the Negative NAO period faces low atmospheric pressure in the Northern Atlantic region. Thus, this affects the level of precipitation.

The difference in the NAO causes significant changes to the climate. In turn, this influences the ecological process. For instance, a shift in temperature and precipitation can affect fishing and disrupt international agreements. The changes in storminess in the NAO is shown by the convergence and movement of the atmospheric pressure. During winter, when the NAO index is high, the Canadian Arctic and Greenland areas experience more evaporation in contrast to precipitation. The NAO also affects subsurface ocean changes. For instance, NAO brings about changes in oceanic and atmospheric conditions for the oceanic MLD. Nevertheless, research also depicts that sea ice reduction is connected to the negative shift of the NAO index. The different phases of the NAO prove that they can be portrayed by both higher than the average air pressure and lower than the average air pressure of different regions.

Works Cited

Boström, Patrik. "NAO Index: An Extreme Pressure Approach.". Diva-Portal.Org, 2014, https://www.diva-portal.org/smash/get/diva2:714920/FULLTEXT01.pdf.

Caian, Mihaela, et al. "An interannual link between Arctic sea-ice cover and the North Atlantic Oscillation." Climate dynamics 50.1-2 (2018): 423-441.

Dahlman, LuAnn. "Climate Variability: North Atlantic Oscillation". Climate.Gov, 2009, https://www.climate.gov/news-features/understanding-climate/climate-variability-north-atlantic-oscillation#:~:text=NAO's%20positive%20phase%20The%20NAO,shift%20of%20the%20storm%20track.

Hurrell, James W., and Clara Deser. "North Atlantic climate variability: the role of the North Atlantic Oscillation." Journal of marine systems 79.3-4 (2010): 231-244.

Riaz, Syed MF, M. J. Iqbal, and Sultan Hameed. "Impact of the North Atlantic Oscillation on winter climate of Germany." Tellus A: Dynamic Meteorology and Oceanography 69.1 (2017): 1406263.