8. Atmospheric Sciences
The atmospheric environment impacts every aspect of Army operations. Fog, rain, snow, and aerosols and smokes from battlefield sources are a few obvious factors influencing Army strategy, mobility, and weapons delivery. Prior, quantitative knowledge of present and future environmental conditions, consequences, and limitations is essential for intelligence preparation of battlefield, for developing improved weapon systems, and for enhancing the Army's "all-weather" capability. Under the Project Reliance, the Army has primary responsibility for scientific issues concerning the atmospheric boundary layer over the land. Furthermore, the Army has the responsibility for providing environmental data for its own needs at battlefield and smaller scales.
b. Major Research Areas
Better capabilities for predicting and using adverse weather effects as force multipliers require basic understanding of the physical processes of the atmosphere on scales ranging from continental to the engagement scales (Figure V17). Basic research in the atmospheric science is multidisciplinary--using understanding of electromagnetic and acoustic propagation in the atmosphere, fluid dynamics and turbulence, radiative energy transfer, and thermodynamics of mixed phases of water are needed to assess the natural and induced environments over the land. The Army's Atmospheric Sciences Coordinating Group, with representatives from ARO, ARL Directorates, TECOM, NOAA, academia, and industry, developed a strategic plan for focusing future research by identifying and assigning priorities to promising research thrusts. Two primary subject areas were identified:
(1) Propagation and Remote Sensing
(2) Boundary Layer Meteorology
Figure V-17. In the future, weather prediction will improve and be applicable to smaller areas of military operations.
Present and future research focuses principally on the atmospheric boundary layer where the Army operates at high time and spatial resolution. These research thrusts stress fundamental understanding of the atmospheric boundary layer and the processes of its interaction with the natural ground surface. In particular, the scientific issues are of interest:
(1) Effects of heterogeneous conditions of surface heat, mass, and momentum exchange
(2) Stability conditions from very stable to fully convective
(3) Inhomogeneous turbulence on models of contaminant dispersion and of acoustic and electromagnetic propagation are emphasized
These issues have direct bearing on chemical/biological defense, atmospheric effects on weapon systems and operations, and predictability of atmospheric conditions.
To advance the understanding at these scales, high resolution measurements are needed but are currently unavailable. Development of a capability for remote sensing of the atmospheric boundary layer for high resolution of wind velocity, temperature, and moisture in four -dimensions (x,y,z,t) will continue as a major research thrust. The sensed data should provide quantitative information on the inhomogeneity of the atmosphere as a propagation (electro magnetic and acoustic) medium and as a dispersing medium for natural and induced aerosols. Propagation research concentrates on developing physically based models of atmospheric propagation in a variety of environments. The models address electromagnetic frequencies from the ultraviolet through millimeter wave and acoustic frequencies from 1 to 1000 Hz. Developing reliable imaging models for predicting atmospheric effects on sensors or system imaging performance, especially in inhomogeneous conditions, will improve evaluations of systems before going to field tests or deployment. The models will also be used to examine atmospheric effects on aided target recognition (ATR) performance and to improve ATR algorithm development. Fundamental studies investigate the interaction of electro magnetic waves with the natural earth surfaces for detection of subsurface objects. Passive spectroscopy of features of the earth surface is developing a major library of reflectance and radiance data to support the modeling and rapid detection of natural and manmade features, including camouflage.
c. Other Research Areas
Research efforts in understanding the detection, identification, and quantification of chemical and biological aerosols will continue. Research thrusts in this area are expected in the development of laboratory capabilities that are later transferred to field applications or techniques.
d. Benefits of Research
Boundary Layer Meteorology research serves all Services through improved characterization (parameterizations) of boundary layer processes over land in weather prediction models. It also supports multiple functions of the Army's Integrated Meteorological System in intelligence preparation of the battlefield. Research in turbulent dispersion of aerosols and gases leads to a significantly improved dispersion model applicable to open detonation/open burning of munitions; to improved prediction of transport and diffusion of chemical, biological, and nuclear materials on short time and space scales, over varied terrain shapes and ground covers, and all times of day; and to modeling effectiveness of smoke and other obscurants in realistic scenarios.
Remote sensing of wind fields will also enable detection of hazardous winds in aircraft landing zones, in paradrop zones, and in accidental release of hazardous gases or aerosols. Active and passive remote sensing research is essential to detection of objects in snow or on the ground, modeling and rapid detection of natural and manmade features, including camouflage, and millimeter-wave propagation at low grazing angles over and through a variety of vegetation.