a device that measures temperature thermometers a scientific instrument used in meteorology to measure atmospheric pressure barometer the weight of the Earth's atmosphere pressing down on everything on the surface. air pressure is the science of the upper region of the atmosphere, where dissociation and ionization are important. aeronomy is the study of the changes in temperature, air pressure, moisture, and wind direction meteorology a measure of the amount of heat in a material temperature the study of weather over long periods of time climatology the movement of air from a location of high pressure to a location of low pressure wind wetness caused by water moisture is a tool for determining the direction the wind is blowing. wind vane measure wind speed anemometers the temperature at which air must be cooled at constant pressure in order for it to become saturated with respect to a plane surface of water dew point a device used to measure relative humidity of a certain area psychrometer the amount of water vapor in the air humidity a person who studies or predicts the weathe meteorologist type of instrument used to gather and measure the amount of liquid precipitation over a set period of time rain guage the amount of moisture in the air compared to what the air can "hold" at that temperature relative humidity an instrument used for measuring the moisture content in the environmental air, or humidity hygrometers a type of tropical cyclone hurricane any dangerous meteorological phenomena with the potential to cause damage, serious social disruption, or loss of human life severe weather an offshore rise of water associated with a low pressure weather system surge storm lumps of ice that are normally fairly round hail Study the following terms