Aeolus scientific disciplines - Climate studies
Climate studies aim to learn more about the atmosphere and weather systems on Earth. By recording and monitoring the weather in different parts of the world, scientists can build complex models to predict the climate of the future, based on trends over the last few years. This information can then be used to reach conclusions concerning, for example, global warming, and the effects of pollution upon the weather.
Aeolus: creating a better model
Obviously, the more information available about the current climate, the more accurate these predictions can be. In this respect, Aeolus offers improved possibilities for climate studies. The satellite can retrieve information from anywhere on the planet, including very remote areas. The on-board DWL will create a wind profile that shows the relative strength and direction of winds at different altitudes, as well as giving information on factors such as moisture and dust levels in the atmosphere.
The mission will provide:
- measurements of global three-dimensional wind fields, which will give a more accurate picture of the Earth's global energy budget
- data concerning global atmospheric circulation and related features such as precipitation systems, the El Niño and the Southern Oscillation phenomena, the distribution of atmospheric constituents like ozone or aerosol, and stratosphere/troposphere exchange.
Process research is needed to improve understanding of the climate system and the capability to model climate and detect, attribute and predict climate change on decadal and centennial time scales. This is addressed by the World Climate Research Programme (WCRP), whose overall objectives are to observe, understand, model and predict climatic variations and climate change. In particular, through Climate Variability and Predictability (CLIVAR) and the Global Energy and Water Cycle Experiment (GEWEX) the WCRP places a high priority on achieving accurate computations (and therefore a better understanding) of energy and water fluxes on the global scale, which determine the current state and the future evolution of the climate.
The GEWEX Scientific Steering Group has already highlighted the need for accurate global measurements of tropospheric winds for numerical weather forecasting and climate studies. Indeed, it has identified inadequate tropospheric wind measurements as one of the three global data areas of most concern for GEWEX studies (the other two being, cloud, aerosol and radiation measurements, and soil moisture measurements) and therefore warranting the highest scientific priority. Since Aeolus can provide accurate measurements of tropospheric winds, it will directly address the need for more data in this area.
The CLIVAR research programme aims at further understanding of the physical processes in the climate system which are responsible for climate variability on time scales ranging from seasons to centuries. The collection and analysis of observations, as well as development of global, coupled ocean-atmosphere predictive models, are the main activities within CLIVAR. Key data for understanding climate variability relate to the processes (very dependent on wind) that govern the coupling between the oceans and the atmosphere on a global scale. Within CLIVAR, the El Niño and Southern Oscillation system (ENSO) and monsoon systems in the tropics, have been identified as principal research areas. In addition, climate variability over a decadal and centennial time-frame, and human influences on climate change are major programme topics. In all of these areas, the wind-profile data from Aeolus will be of great benefit.
The WCRP in general, and GEWEX and CLIVAR in particular, require knowledge of basic meteorological variables to estimate energy and water transformation in the atmosphere and fluxes at the air-sea interface. Tropospheric winds remain a weak point. This deficiency poses a considerable limitation for scientific diagnostics of large-scale processes. The problem is most serious in the tropics where the wind field is a critical dynamical variable. Tropical winds in particular are currently very poorly determined because of the almost complete lack of direct observations. In the CLIVAR context requirements for surface fluxes are specified. To meet these requirements, wind and humidity structure in the lower troposphere need improvement. Again, Aeolus will be able to provide the required improvement.
Many remote-sensing data on atmospheric composition are and will become available. The transport of constituents through the atmosphere often determines to a large extent their spatial distribution. A new global three-dimensional wind-sensing system, such as Aeolus, will improve the representation of transports in the models of the atmosphere and, consequently, the spatial distribution of atmospheric constituents. This will aid in the validation and calibration of variables in atmospheric chemistry.