A PAPER ON LOCATION AND DESIGN OF A WEATHER STATION BY AJILORE YEJIDE ARC/O5/5583 AJAO OLAWALE ARC/05/5581 AJIBOLA YEMI ARC/05/5582 Submitted to the Department of Architecture In partial fulfillment of the course Environmental Control (CLIMATE) ARC 309 April, 2008 TABLE OF CONTENT 1.0 INTRODUCTION 1.1 WEATHER STATION 2.0 TYPES OF WEATHER STATION 3.0 INSTRUMENT IN A WEATHER STATION 3.1 THERMOMETER 3.2 BAROMETER 3.3 RAIN GUAGE 3.4 WIND VANE 3.5 ANEMOMETER 3.6 STEVENSONS SCREEN 4.0 FACTORS AFFECTING THE DATA GOTTEN FROM A WEATHER STATION 4.1 DIFFERENCE IN ALTITUDE 4.2 COASTAL OR INLAND NATURE OF LOCATIONS 4.3 NEARNESS TO URBAN CENTERS 4.4 OBSTRUCTION CAUSED BY GROUND COVER AND TOPOGRAPHY 5.0 LOCATION AND DESIGN OF A WEATHER STATION REFERENCES 1.0 INTRODUCTION Weather is measured so as to determine the changes weather elements and variations in factors affecting climate which cannot be achieved without the use of a Weather Station which houses the various instrument that measures the various weather elements .there are various types of weather stations with respect to their functions-synoptic Synoptic Agricultural weather station, Climatological weather station, Rainfall weather station. The design of a weather station involves locating a suitable environment and siting the needed instrument using the appropriate design. 1.1 WEATHER STATION A weather station is a facility with instruments and equipment to make Observations of atmospheric conditions in order to provide information to make weather forecasts and to study the weather and climate of a particular area. It could also be defined as a meteorological observation post where meteorological conditions are observed and recorded. 2.0 TYPES OF WEATHER STATIONS . Measurement of weather elements or weather observations are carried out at various weather stations .there are specifically four types of weather stations which can be recognized depending on the number of weather elements measured, the frequency of measurement ,and the status of the observer whether professional or amateur. There specifically four types of weather station which includes: 1. Synoptic weather station 2. Agricultural weather station 3. Climatological weather station 4. Rainfall weather stations 1. Synoptic weather station : these are stations manned by full-time a Professional observers who maintain continuous weather watch and make Hourly instrumental observations of the weather elements on which information is required for the compilation of the synoptic charts or weather maps used in weather forecasting. Synoptic weather stations typically report near real-time (hourly, 6-hourly, daily) automated weather information using a communication system (satellite or modem). they collect detailed data on air temperature, precipitation amount and intensity, wind speed and direction at a height of 10 m above the ground, atmospheric pressure, visibility, cloud cover and type, hours of bright sunshine, solar radiation ,humidity, dew point temperature and, in a few cases, snow depth and evaporation. The information from these stations is used in preparing weather forecasts and in calculating climatic information. 2. Agricultural weather station : These are stations manned by part-time observers making at least twice daily instrumental observations of the major weather elements: evaporation, grass and soil temperatures, and solar radiation are also usually measured in view of their obvious importance in agriculture 3. Climatological weather station : These are stations manned by part-time observers making only once or twice daily instrumental observations of temperature, humidity, rainfall, and wind . Climate stations typically report less frequently (daily, twice-daily, weekly, monthly) and may be automated or manually operated by professionals. These stations collect daily temperature and precipitation information, and some used to collect precipitation only. 4. Rainfall weather stations : These are stations manned by part-time observers who take daily readings of rainfall only. Rainfall is measured by catching it in a calibrated rain gauge. At most climate stations, a volunteer observer measures rainfall intensity using a standard Canadian rain gauge called a type b rain gauge. The gauge sits about 40 centimeters (cm) above the ground and has a circular opening 11.3 cm in diameter. The rain is funneled into a clear plastic cylinder which measures the contents to the nearest 0.2 mm. the majority of climate station observers measure the depth of new snow using a ruler. They estimate the amount of moisture in the snow by assuming a snow density of 100 kilograms per cubic meter. Snow depth is read to the nearest 0.2 cm with less than 0.1 cm is recorded as a trace. The Canadian nipper shielded snow gauge system is the standard instrument for measuring fresh snowfall water equivalent. It is used at a limited number of stations. 3.0 INSTRUMENTS USED IN A WEATHER STATION The typical weather station has the following instrument -Thermometer for measuring temperature -Barometer for measuring barometric pressure -Hygrometer for measuring humidity -Anemometer for measuring wind speed -Wind vane for measuring wind direction -Rain gauge for measuring precipitation Except for those instruments requiring direct exposure to the elements (i.e anemometer, rain gauge), the instruments should be sheltered in a vented box, called a STEVENSON SCREEN, to keep direct sunlight off the thermometer and wind off the hygrometer. The instrumentation may be specialized to allow for periodic recording otherwise significant manual labor is required for record keeping. 3.1 THERMOMETER A Clinical Thermometer A thermometer is a device that measures temperature or temperature gradient, using a variety of different principles. The word thermometer is derived from two smaller word fragments: thermo from the Greek for heat and meter also from Greek, meaning to measure. A thermometer has two important elements, the temperature sensor (e.g. the bulb on a mercury thermometer) in which some physical change occurs with temperature, plus some means of converting this physical change into value (e.g. the scale on a mercury thermometer). Industrial thermometers commonly use electronic means to provide a digital display or input to a computer. Thermometers can be divided into two groups according to the level of knowledge about the physical basis of the underlying thermodynamic laws and quantities. For primary thermometers the measured property of matter is known so well that temperature can be calculated without any unknown quantities. Examples of these are thermometers based on the equation of state of a gas, on the velocity of sound in a gas, on the thermal noise (see Johnson–Nyquist noise) voltage or current of an electrical resistor, and on the angular anisotropy of gamma ray emission of certain radioactive nuclei in a magnetic field. Secondary thermometers are most widely used because of their convenience. Also, they are often much more sensitive than primary ones. For secondary thermometers knowledge of the measured property is not sufficient to allow direct calculation of temperature. They have to be calibrated against a primary thermometer at least at one temperature or at a number of fixed temperatures. Such fixed points, for example, triple points and superconducting transitions, occur reproducibly at the same temperature. Internationally agreed temperature scales are based on fixed points and interpolating thermometers. The most recent official temperature scale is the International Temperature Scale of 1990. It extends from 0.65 K to approximately 1358 K (−272.5 °C to 1085 °C). 3.2 BAROMETER A barometer is an instrument used to measure atmospheric pressure. It can measure the pressure exerted by the atmosphere by using water, air, or mercury. Pressure tendency can forecast short term changes in the weather. Numerous measurements of air pressure are used within surface weather analysis to help find surface troughs, high pressure systems, and frontal boundaries. Schematic drawing of a simple mercury Barometer with vertical mercury column and reservoir at base. WATER-BASED BAROMETERS This concept of "decreasing atmospheric pressure predicts stormy weather" was invented by Lucien Vidie and is the basis for a basic weather prediction device called a weather glass or thunder glass. It can also be called a "storm glass" or a "Goethe barometer" (the writer Goethe popularized it in Germany). It consists of a glass container with a sealed body, half filled with water. A narrow spout connects to the body below the water level and rises above the water level, where it is open to the atmosphere. When the air pressure is lower than it was at the time the body was sealed, the water level in the spout will rise above the water level in the body; when the air pressure is higher, the water level in the spout will drop below the water level in the body. A variation of this type of barometer can be easily made at home.[3] Mercury barometers A standard mercury barometer has a glass tube of about 30 inches (about 76 cm) in height, closed at one end, with an open mercury-filled reservoir at the base. Mercury in the tube adjusts until the weight of the mercury column balances the atmospheric force exerted on the reservoir. High atmospheric pressure places more force on the reservoir, forcing mercury higher in the column. Low pressure allows the mercury to drop to a lower level in the column by lowering the force placed on the reservoir. Since higher temperature at the instrument will reduce the density of the mercury the scale for reading the height of the mercury is adjusted to compensate for this effect. Torricelli documented that the height of the mercury in a barometer changed slightly each day and concluded that this was due to the changing pressure in the atmosphere[2]. He wrote: "We live submerged at the bottom of an ocean of elementary air, which is known by incontestable experiments to have weight". The mercury barometer's design gives rise to the expression of atmospheric pressure in inches or millimeters (torr): the pressure is quoted as the level of the mercury's height in the vertical column.