Research project objectives/ Research hypothesis

This project aims to achieve four basic objectives: 1) to gather into a database all available Arctic Climate System (ACS) data relating to: the near-surface layer of air (air temperature at 2m (SAT), air pressure, humidity, precipitation, cloudiness, sunshine, solar radiation, wind direction and speed, etc.); the free atmosphere (aerological data); the surface condition of marine waters (surface temperature, SST and ice cover); and continental ice (mainly the reach of glacier terminuses); 2) to analyse and present the most detailed possible description of the Arctic climate and its changes, both temporal and spatial, over the period 1921–1950; 3) to make a significant contribution to the clarification of the causes of the greatest Arctic warming of the 20th century, which took place in the aforementioned period, through the use of climate modeling; and 4) to examine the differences and similarities between the states and changes of ACS during the Early-Twentieth-Century Warming (ETCW) and those of the contemporary period (1981–2010), and the factors shaping them. Our main research hypothesis in this project is that the Arctic warming of the ECTW period was caused by natural factors.

Research project methodology

Under this project, query work will be conducted in European libraries and archives in cooperation with Norwegian and Russian researchers. Additionally, internet-based sources will be comprehensively exploited. Once verified for quality and homogeneity, the digitalized meteorological data relating to ETCW will be analysed in order to determine changes over time and across geographical space, through the use of modern methods employed in climatology. Other elements of ACS, such as SST and selected cryospheric elements (sea-ice extent, glacier fluctuations), will be subjected to similar analysis. Changes over time will be analysed both over the annual cycle and year-on-year.
The impact of solar radiation and cloud cover on climatic conditions during the ETCW period, which is essential in order to accurately determine the parameters of that factor in modeling works, will also be evaluated. In order to evaluate the degree of weakening of solar radiation passing directly through the Earth's atmosphere—which is affected by factors both anthropogenic (increasing air pollution) and natural (e.g., volcanic eruptions)—the Linke turbidity factor and the coefficient of atmosphere transparency will be calculated.
The project will also analyse changes in atmospheric circulation; these are the most commonly-cited cause of the sudden and long-lasting warming of the ETCW period. To this end, daily atmospheric circulation catalogues and circulation indicators and indices for the Atlantic Arctic will be used. Statistical correlations will be established between atmospheric circulation on the one hand, and climate elements, SST and sea-ice extent on the other.
The problem of the causes of climate changes in the Arctic during the ECTW will be analysed using various statistical techniques, and above all with the help of a HIRHAM5 regional climate model, developed by the Alfred Wegener Institute in Potsdam, Germany. The dynamics of the vertical structure and stratification of the Arctic atmosphere during the ETCW will be studied, and more broadly, its baroclinicity, which is in turn closely associated with large-scale atmospheric circulation. The HIRHAM5 model will be evaluated using new aerological data obtained during the archival query works.
In order to evaluate the scale of Arctic climate change between the ETCW and the contemporary period, data (WMO Climate Normals) from the period 1981–2010 will be used.

Expected impact of the research project on the development of science, civilization and society

Clarification and proof of the effect of man on the contemporary Arctic climate requires the natural changes of climate in this region to be identified. Human impact was undoubtedly very limited—even negligible—until about 1920, before gradually rising until its effects were noted in the 1950s. In recent years, with contemporary climate warming (since 1975) following a very similar progression to that of the ETCW, there has been renewed interest in the insufficiently-well explained causes of the ETCW; this has involved the use of newer study methods, foremost among which have been climate models. Among the scientific community there has been heightened interest in an in-depth explanation of the causes of both episodes of climatic warming. Understanding the true mechanisms of climate changes during the ETCW is important to our ability to simulate reliable, future climate scenarios.