My Philosophy of Atmospheric Sciences
September 2017 @ University of Michigan
So far I have been studying atmospheric sciences for more than ten years and I am keen to build my career in this field. Although atmospheric science is deeply rooted in physics, chemistry, mathematics, and computer sciences, this discipline has a number of unique features and makes it stand out from other fields. In this essay, I would like to share my perspective on atmospheric sciences and my goals as an atmospheric scientist.
One of the interesting features in the atmosphere is strong multiscale interactions. Atmospheric phenomena occur over a broad range of temporal and spatial scales. For example, typically a cloud droplet is several microns large and lasts for minutes, while a synoptic cloud system can extend to thousands of kilometers and last for days. The features of cloud droplets, such as their compositions and size distribution, can affect the extent and duration of a synoptic cloud system. On the other hand, the dynamical and thermodynamical characteristics of a cloud system can also influence the features of cloud droplets. There are strong and close multiscale interactions in clouds and in other phenomena as well. In order to fully understand these atmospheric phenomena, we need to know the processes on different scales and the interactions among them. Formulating these multiscale interactions, also known as parameterization, poses a great challenge for atmospheric scientists.
Another interesting feature of the atmosphere is intrinsic continuity with regard to time and space. With regard to time, weather phenomena these days are more or less similar to those of thousands of years ago, e.g. clouds, rain, and tornados. This similarity, however, does not mean the atmosphere remains unchanged over time. In fact, the atmosphere has been changing all the time in response to external factors (such as solar activities and the Earth’s orbit), and to internal factors (such as the ocean and all creatures including humans). Some of these changes can last for a long time and affect the following weather and climate. For example, Mount Pinatubo in the Philippines erupted in 1991 and injected tons of sulfur dioxide and ash particles into the atmosphere. It is believed that this eruption cooled the global mean temperature by 0.1 to 0.15 degree Celsius in the ensuing few years. In addition to natural factors, human-induced climate changes due to fossil fuels burning have affected people around the world and very likely the future generations. With regard to space, weather phenomena occur across the globe and even though people live in different places, they experience similar weather conditions, such as rainy/sunny, hot/cold, and dry/humid. Furthermore, the atmospheric or surface conditions in one region can affect the weather in another region that is far away from it. For instance, relatively warmer sea surface temperature lasting for at least few months over the tropical Eastern Pacific, also known as El Niño, can lead to less amount of rainfall on the other side of Pacific, which is thousands of kilometers apart. Because these temporal and spatial continuities of the atmosphere, questions that we want to know are approximately the same as those people had in the past, such as “Will it rain tomorrow?”, “Will this winter be colder or warmer compared to the last year?”, or “How much rainfall we will get in the following years?” Tackling and answering these ancient and long-standing questions is one of the goals of atmospheric scientists.
To be honest, I do not think one day people can perfectly predict weather and climate. Despite that our understanding of the atmosphere and observation capabilities have been significantly progressed, we still do not fully understand the atmosphere and the complicated interactions with humans, ocean, land, biosphere, among others. The atmosphere is extremely complex and is constantly changing, making it almost impossible to perfectly predict weather and climate in any foreseeable future. If that is the case, what is the purpose of studying the atmosphere?
Although “perfect” predictions for the weather and climate are nearly impossible, “useful” predictions are tractable and indeed valuable. For decision makers and the public, if they were considering how much rainfall that a coming hurricane will bring, a prediction of 800 millimeters with an uncertainty range of 50 mm is way more useful than the same predicted value but with uncertainty of 500 mm. The latter is too uncertain to make plans accordingly. It is fair to say the merit of the atmospheric predictions is not judged solely based on how exact the predicted value is, but how useful of this value. Many atmospheric scientists have dedicated their entire careers to studying the atmosphere and to reducing these uncertainties. These scientists do not stop their steps owing to limited resources such as computing powers or insufficient observation data. Instead, they use all resources they can get at that time to investigate the atmosphere. Their efforts undoubtedly advance our understanding of the atmosphere and feed the future scientists. As I continue as an atmospheric scientist, I will keep pushing forward our knowledge about the atmosphere, just like what scientists did in the past, and I wish all my efforts will advance the field so that future scientists can stand even higher and look further!