Weather: The state of the ATMOSPHERE over minutes to months.Wind: The motion of air relative to the earth's surface.Rain: Water particles that fall from the ATMOSPHERE.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Meteorological Concepts: The atmospheric properties, characteristics and other atmospheric phenomena especially pertaining to WEATHER or CLIMATE.Climate: The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Humidity: A measure of the amount of WATER VAPOR in the air.Meteorology: The science of studying the characteristics of the atmosphere such as its temperature, density, winds, clouds, precipitation, and other atmospheric phenomena and aiming to account for the weather in terms of external influences and the basic laws of physics. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Snow: Frozen water crystals that fall from the ATMOSPHERE.Atmospheric Pressure: The pressure at any point in an atmosphere due solely to the weight of the atmospheric gases above the point concerned.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Radar: A system using beamed and reflected radio signals to and from an object in such a way that range, bearing, and other characteristics of the object may be determined.Climate Change: Any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). It may result from natural factors such as changes in the sun's intensity, natural processes within the climate system such as changes in ocean circulation, or human activities.Solar Activity: Any type of variation in the appearance of energy output of the sun. (NASA Thesaurus, 1994)Poisson Distribution: A distribution function used to describe the occurrence of rare events or to describe the sampling distribution of isolated counts in a continuum of time or space.Spatio-Temporal Analysis: Techniques which study entities using their topological, geometric, or geographic properties and include the dimension of time in the analysis.Air Pollution: The presence of contaminants or pollutant substances in the air (AIR POLLUTANTS) that interfere with human health or welfare, or produce other harmful environmental effects. The substances may include GASES; PARTICULATE MATTER; or volatile ORGANIC CHEMICALS.Heat Stress Disorders: A group of conditions that develop due to overexposure or overexertion in excessive environmental heat.Greenhouse Effect: The effect of GLOBAL WARMING and the resulting increase in world temperatures. The predicted health effects of such long-term climatic change include increased incidence of respiratory, water-borne, and vector-borne diseases.Frostbite: Damage to tissues as the result of low environmental temperatures.Accidents, AviationAir Movements: The motion of air currents.Floods: Sudden onset water phenomena with different speed of occurrence. These include flash floods, seasonal river floods, and coastal floods, associated with CYCLONIC STORMS; TIDALWAVES; and storm surges.Cold Temperature: An absence of warmth or heat or a temperature notably below an accustomed norm.Air Pollutants: Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or material. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.Mortality: All deaths reported in a given population.Environmental Monitoring: The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.Disasters: Calamities producing great damage, loss of life, and distress. They include results of natural phenomena and man-made phenomena. Normal conditions of existence are disrupted and the level of impact exceeds the capacity of the hazard-affected community.Population Dynamics: The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.Sulfur Dioxide: A highly toxic, colorless, nonflammable gas. It is used as a pharmaceutical aid and antioxidant. It is also an environmental air pollutant.Hebrides: A group of islands in the Atlantic Ocean west of Scotland, comprising the Outer Hebrides and the Inner Hebrides.Animal Migration: Periodic movements of animals in response to seasonal changes or reproductive instinct. Hormonal changes are the trigger in at least some animals. Most migrations are made for reasons of climatic change, feeding, or breeding.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Ecosystem: A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)