The Institute of Oceanology, RAS has created a unique three-dimensional dataset on the state of the atmosphere in the North Atlantic over the last 40 years using numerical simulations. The model on the basis of which was created this array is publicly available and allows high resolution to reproduce about 200 basic parameters of the atmosphere, which gives the opportunity to observe atmospheric phenomena such as thunderstorms and typhoons, and to assess their impact on the global climate of the Earth. In the future, the researchers plan "to expand the geography" of their model, that such phenomena could be studied throughout the world. An article recently published in the Journal of Applied Meteorology and Climatology. Research supported by grants from the Russian science Foundation (RNF).
"three-Dimensional array meets a range of research requirements of meteorologists, climatologists and oceanographers working in both the research and operational areas. The created model serves as a unique source of data for models of ocean circulation due to its high spatial resolution. This will more accurately reproduce the dynamics of the ocean in the global climate change and weather prediction", — said Natalia Tilinina, head of the project for grant of RF, candidate of physico-mathematical Sciences, senior researcher of the Institute of Oceanology named after P. P. Shirshov of RAS (Moscow).
The last two decades to predict the weather, study the climate and climate change, and more specifically to describe the structure of the atmosphere and the processes helps scientists numerical simulation. Global General circulation model of atmosphere and ocean covered the entire planet, "network" at each node, which are known parameters — pressure, temperature, humidity, wind speed, and others. They allow to study the processes taking place in the twentieth century, and to predict climatic changes in the XXI. But these models lack sufficient accuracy in order to explicitly reproduce the mesoscale (within 10-100 kilometers) and small-scale atmospheric phenomena. To confirm these results, scientists are building a regional model covering a particular region. As boundary conditions use the data of the global modeling, and computations with an increased spatial resolution allow for more options. For example, topography, soil characteristics and vegetation or currents in the oceans that affect the lower layers of the atmosphere.
Scientists of the Institute of Oceanology, RAS reconstructed atmospheric circulation over the North Atlantic over the last 40 years and has created a unique three-dimensional configuration of the model, called the Russian Academy of Sciences North Atlantic Atmospheric Downscaling (RAS-NAAD). To build a model�� the researchers used a database of atmospheric reanalyses — the United observations of the atmosphere collected by satellites, aircraft, ground water and meteorological stations around the world. The reconstruction covers the area over the ocean between 10° North latitude (this parallel is, for example, the border of Sierra Leone and Guinea) to 80° North latitude (well above the Arctic circle).
The model has a spatial resolution of 14 km and allows to reproduce the mesoscale dynamics of the atmosphere and dangerous atmospheric phenomena, such as thunderstorms and typhoons. It covers the atmosphere from the surface to about 20 km above the earth and is divided into 50 vertical levels (relative to the pressure in a dry atmosphere), where the thickness of the surface layers is 10-20 meters, and increases with height up to 500 meters.
Complete archive of NAAD is 150 TB and after some time will be made available to researchers in the form of a separate annual files. Data allow us to analyze about 200 parameters of the surface and the free atmosphere — pressure, temperature, humidity, electrical performance and other — every 3 hours during the period from 1979 to 2018.It is considered that extreme atmospheric phenomena — storms, thunderstorms, forests (cold local winds) do not affect the global climate. So far, however, they were not considered as their "not seen" in the results of climate models because of their coarse resolution, and, in fact, their impact has never been studied. In addition, the global models do not accurately reproduce the interaction of ocean and atmosphere, which, according to the observations, has a significant impact on local weather and continental. Scientists have set a goal to determine how much the change assessing the prognosis of future climate, taking into account all these phenomena.
"it is not known how we can tell about climate change, if not take into account a whole layer of phenomena. Moreover, the climate is changing, and those phenomena that were once rare, now occur more frequently — for example, increasing the number of storms, and to assess its impact on the climate is only possible with the use of high-precision models, — said the author of the article Aleksandr Gavrikov, candidate of physical and mathematical Sciences. We wanted as accurate as possible to restore the state of the atmosphere over the last 40 years. Retrospective models are good that allow you to "reconstruct" and "predict" the phenomenon and to compare calculations with the data of real observations."
Reconstruction created using regional non-hydrostatic model WRF-ARW 3.8.1 — most modern high-precision models in the public domain. With the ability to change its settings, scientists have been able to take into account processesSy, which are characteristic of the region of the North Atlantic. This region is considered "weather kitchen" for the entire Northern hemisphere, and the processes occurring on the border of the ocean and the atmosphere, impact the climate over continents. However, in the future, the researchers plan "to expand the geography of" your model and make of mesoscale phenomena are likely to explore in the world.
