global sea level rise and modeling

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Aho and Niittyvirta drew attention to tidal changes and decided to investigate the theme with interactive artwork. Consequently, they needed
to familiarize themselves with technology and different models to predict and estimate various scenarios. One of the main methods to research future tidal changes is building mathematical models based on the data collected from the past. These simulations are run by computers and tested with various variables to ensure that the results are not biased.

During the 20th century the average sea- level rise rate was 1.7 mm/yr. This is remarkably lower compared to the rate of 3.3 mm/yr during the period from 1993 to 2016. Some estimations for the next century vary from 1 m to 3 m depending on the place in a scenario, where ice from both Greenland and Antarctica glaciers melt (fig.1). (Pickering et al. 2017)

The sea level rise is an urgent matter,
but we have to take into consideration also the tectonic uplift in the areas where land is still rising annually. During the last ice age the land on the peninsula of Scandinavia and Finland was pressed under the thick sheet of ice. Hence, the land still rises in these areas, where the annual uplift is greatest in the Gulf of Bothnia (fig.2). The annual uplift varies from 1 mm/yr to 1 cm/yr. For instance, in Bergen the land rises only 1.1 mm/yr. (fig.3)(Grønnestad. 2014.)

Tidal changes equally affect the ecosystems on the shorelines. World oceans are annually absorbing more than 25% of anthropogenic emissions. This is lowering the pH of the water. The carbon dioxide travels through the ocean in different means. The acidification impacts the marine environment as its species and ecosystems are endangered as the sea level rises to their habitat. This is why modeling and predictions produces relevant information for society. (Villas Boas, et al. 2019.; C. Sabine et al., 2004)

However, building mathematical models can be highly demanding. The circumstances are ever-changing. Morphological changes, dreading, harbour creation, topography and specific locations with anthropogenic factors creates fluctuating baselines. The models need to include also recent data and measurements, so that the changing baseline is taken into consideration. Researching and measurement tools to measure current data are also vital. (Pickering et al. 2017.) A well-designed model uses multiple

parametres revised constantly. Hence, the input provided to the model produces improved forecasts and predictions. Some methods to gather this information are: in situ measurements, satellite images and using microwave radiometers and scatterometers. ‘’Scatterometers are active sensors that measure the fraction of energy from the radar pulse reflected back to the satellite,

also known as backscatter. The backscatter is a function of the sea surface roughness, which is, in turn, a function of the wind speed and direction.’’ (Villas Boas, et al. 2019)

There are numerous initiatives and satellite programmes analyzing the sea from
aerial perspective, European Union’s Copernicus- programme and NASA’s SEASTAR, to mention but a few. The connection between air and sea as well as climate aspect provides information also from the changes in the water. Satellite images are utilized to observe the two-dimensional surface to understand vertical structure of the upper ocean.

From the aerial perspective it is possible to gain information from interactions between air and surface layer of the water. The ultimate aim is to predict future climate and earth system models while developing parameterization of these processes. (https://www.copernicus.eu/; Villas Boas, et al. 2019.)

Observing the surface speed and sea winds there are interactive databases and
maps online, for example tidemap.com. The organization uses advanced GIS technology
to provide metocean data in real time (fig.4). (tidemap.com. 2019.) However, there has to be set, unbiased criteria to evaluate the results and predictions. Data might be insufficient or not cohesive with other variables. The outcomes need to be cross-validated with other results. Reflecting the result to in situ ocean measurements and observations is necessary. (Villas Boas, et al. 2019.)