HYDROMETEOROLOGICAL INSTRUMENTS Presented by: ENGR. JEAH A. BEJARASCO ANEMOMETER are meteorological devices sed to measure wind speeds and can commonly be found in weather stations. Today, except in weather stations, they are widely used in determining the average speed in ventilation systems built in the industrial and residential buildings. ANEMOMETER TYPES OF ANEMOMETER 1. Cup Anemometers Also known as rotational anemometers cup anemometers simplest types of anemometers and have been around for a very long time. As wind presses against these cups, the arms at the top rotate around the central pole. ANEMOMETER TYPES OF ANEMOMETER 2. Windmill Anemometers able to determine the direction of the wind as they have a propeller that is attached to the front of the device with a tail section behind, on the same axis as the propeller on a central pole. 3. Ultrasonic involves sonic pulses to measure the velocity of the wind. The device sends sonic pulses across a path to sensors located across which are able to sense the incoming pulses.. BAROMETER measures atmospheric pressure. Changes in atmospheric pressure are most often caused by the rise of warm air and the descent of cold air Barometric pressure changes with local weather. Rising pressure means fair weather while falling pressure means poor weather. HYGROMETER Hygrometer is a device used for detecting and measuring humidity. There are several types of hygrometers (coil, hair tension, capacitive, resistive and others), whose operation is based on different principles. Rain Gauge A rain gauge is an instrument for measuring the precipitation that has fallen in a given time interval. The rain gauge is part of every weather station. It is used in meteorology as an additional tool of the weather forecast and the climatology for the purpose of long-term statistics of precipitation. The amounts of rain accumulated in the gauge are read either manually or by automatic weather station (AWS). Types of Rain Gauge 1. Non-Recording Type Rain Gauge Non-recording type rain gauge is most common type of rain gauge used by meteorological department. It consists of a cylindrical vessel 127mm in diameter with a base enlarged to 210mm diameter. At its top section, funnel is provided with circular brass rim which is 127mm exactly so that it can fit into vessel well. This funnel shank is inserted in the neck of a receiving bottle which is 75 to 100mm high from the base section and thinner than the cylinder, placed into it to receive rainfall. Types of Rain Gauge 1. Recording Type Rain Gauge There are three types of recording rain gauges a) Weighing bucket type b) Tipping bucket type c) Floating or natural syphon type rain gauge Types of Rain Gauge 1. Recording Type Rain Gauge There are three types of recording rain gauges a) Weighing bucket type b) Tipping bucket type c) Floating or natural syphon type rain gauge