How do we measure the weather and climate?
Outdoor Reading, Analog Hygrometer. Designed to provide an accurate, reliable reading of outdoor relative humidity, the Stratus is a hygrometer made to the . (Image from NASA). A hygrometer is an instrument used to measure relative humidity. Humidity is the measure of the amount of moisture in the air. A psychrometer is an example of a hygrometer. A psychrometer uses two thermometers to measure relative humidity; one measures the dry-bulb temperature and the other measures the wet-bulb temperature.
Most thermometers are closed glass tubes containing liquids such as alcohol or mercury. When air around the tube heats the liquid, the liquid expands and moves up the tube. A scale then shows what the actual temperature is. It tells you whether or not the pressure is rising or falling. A rising barometer means sunny and dry conditions, while a falling barometer means stormy and wet conditions.
An Italian scientist named Torricelli built the first barometer in Two thermometers are used in a sling psychrometer. Wet the cloth of one of the thermometers and swing the psychrometer around a few times.
Water evaporates from the cloth, causing the temperatures on that thermometer to be lower than the other. The cups catch the wind, turning a dial attached to the instrument. The dial shows the wind speed. Meteorologists use weather maps to forecast the weather.
Then meteorologists compile and analyze the data with the help of computers. Radar What is radar? How to get new logbook for car ireland is an electronic instrument, which determines the direction and distance of objects that reflect radio energy back to the radar site.
It stands for Radio Detection and Ranging. This is what meteorologists use to see rain or snow. What is Doppler Radar? Doppler Radar detects precipitation intensity, wind direction and speed, and provides estimates of hail size and rainfall amounts. Doppler Radar gives forecasters the capability of providing early detection of severe thunderstorms that may bring strong damaging winds, large hail, heavy rain, and possibly tornadoes.
Combined with satellites, radar gives forecasters the ultimate tools to provide accurate forecasts and advanced severe weather warnings. How does Doppler Radar work? Doppler Radar gets its name from the Doppler Effect. Have you ever listened to a train whistle as it was coming toward you? You probably noticed that the pitch of the whistle changed as the train passed you and moved away.
This change in the frequency of sound is called the Doppler Effect. Doppler Radar measures the changes in the frequency of the signal it receives to determine the wind.
This radar produces many different views of storms and rain that allows meteorologists to determine if a storm could be severe. Weather Instrument Activities Thermometer Experiment: Here is a great experiment that allows the kids to make a thermometer.
Rain Gauge Experiment: Here is an experiment that allows a kids to make their very own rain gauge. They can learn how the Doppler Effect works and why Doppler Radar is such as important tool in weather forecasting. Anemometer Experiment: Here is another great experiment that lets kids make an anemometer or wind vane.
Windsock Experiment: Here is an what is the best blood pressure reading to have that allows the kids to make a windsock. Pressure Experiment: Here is an experiment that shows how pressure is created in our atmosphere by sucking an egg in a bottle. This is a very cool experiment!
Make A Barometer Experiment: Here is an experiment that allows the kids to make a barometer. Make A Barometer Experiment 2: Here is an experiment that allows the kids to make a barometer. Weather Instruments. Weather Instrument Activities.
from Campbell Scientific, Inc. The WXT is a solid-state, all-in-one weather instrument that measures wind speed and direction, precipitation, barometric pressure, temperature, and relative humidity. It puts out an SDI signal that can be measured by many of our dataloggers. Apr 23, · Hygrometers measure temperature and humidity using degrees Celsius and degrees Fahrenheit. One type of hygrometer, called a sling psychrometer, uses one dry and one wet bulb thermometer to measure the relative humidity of the air. Some older hygrometers used a sheaf of hair, which increases in length as relative humidity increases. Our ECONet weather towers measure a variety of these parameters, such as temperature, wind speed, wind direction, humidity, precipitation, atmospheric pressure, solar radiation, and even soil .
Weather instruments are used to take measurements of temperature, wind, precipitation, and other atmospheric factors that describe the local weather and climate. Different types of instruments are used to measure these parameters and there are many types to choose from. Our ECONet weather towers measure a variety of these parameters, such as temperature, wind speed, wind direction, humidity, precipitation, atmospheric pressure, solar radiation, and even soil temperature and moisture!
Temperature Show More. Think about what a thermometer looks like. Chances are you probably thought of the classic glass tube filled with red-dyed alcohol — replacing toxic mercury-filled instruments Figure A.
As the temperature of the instrument changes, so too does the volume of the liquid inside of the thermometer — the red liquid rises as the temperature rises due to the liquid expanding up the tube, and falls with the temperature due to the liquid contracting back into the bulb at the bottom. At modern weather stations, like our ECONet towers, an electronic temperature sensor is used to measure the outside air temperature Figure B. The temperature sensor on this device is contained within a vented unit which allows air to flow freely across the sensor and measure the temperature while keeping the thermometer shaded from the direct heating of the sun.
There are a few different types of anemometers, one of the most common being a cup anemometer Figure C — right side. As the wind blows, it pushes the cups and causes the arms to rotate at a rate proportional to the wind speed.
A wind vane can help us to measure which direction the wind is coming from Figure C — left side. As the wind blows past the instrument, the wind vane will point in the direction that the wind is coming from.
It is important to note that wind direction is always given by where the wind is coming from, so a west or westerly wind is blowing from west to east. Many weather stations, including our ECONet towers, use a tool that combines these two instruments into one called a propeller anemometer Figure D. Because propeller anemometers measure both speed and direction simultaneously, they are considered to be more accurate than the two separate instruments.
Precipitation Show More. A rain gauge is an instrument used to measure the amount of precipitation over a certain amount of time. In its most basic form, a rain gauge can be a bucket that collects rain water to be measured by a ruler Figure E. Specifically, our ECONet rain gauges are known as tipping bucket gauges Figure F — when the gauge fills to a certain level 0.
The number of bucket-tips are counted and the precipitation is calculated. For example, if the bucket tips 25 times over the course of the day, we can calculate that it rained 0.
In order for rain gauges to be as precise as possible, they need to be placed in open areas with no obstructions like trees or buildings. The goal in measuring weather is always accuracy, but sometimes real-world weather conditions impede our measurements. Atmospheric Pressure Show More. Atmospheric pressure, or air pressure, can be measured using a barometer. An aneroid barometer Figure G , one of the most common types, uses a sealed container of air to detect changes in the atmospheric pressure outside of the container.
As the atmospheric pressure increases, it pushes down on the container and it is slightly reduced in volume, moving an indicator needle towards higher pressure. If the atmospheric pressure decreases, the container expands slightly and the needle indicates lower pressure. Measuring pressure is important because it is related to volume, density, and temperature. In the atmosphere, warm surfaces can heat the air above them causing the air to become less dense and to rise.
This leads to low pressure and can eventually result in clouds and precipitation in the areas of rising motion. On a large scale, these low pressure systems can become large storm systems, such as hurricanes. On the other hand, high pressure in the atmosphere causes the cold air to compress and sink, leading to clear skies and calm conditions.
Notice the associated weather on the barometer in Figure H. Humidity Show More. Humidity is defined as the measure of moisture in the air. It is important to keep in mind that relative humidity is also dependent on air temperature. For example, if the water vapor content stays the same and the temperature drops, the relative humidity increases. If the water vapor content stays the same and the temperature rises, the relative humidity decreases.
Relative humidity can be measured using a hygrometer. The dry-bulb thermometer will simply measure the air temperature while the wet-bulb measures evaporative cooling. Evaporative cooling is the reason you feel cold after getting out of a swimming pool or the shower.
The water uses heat energy from your body and your skin cools to the wet-bulb temperature which is why you feel a chill until the water evaporates. A sling psychrometer Figure I is a common type of hygrometer used to determine relative humidity. Sling psychrometers use two thermometers one dry-bulb, one wet-bulb to measure and compare the air temperature versus the evaporative cooling. These measurements are then compared to a relative humidity chart Figure J to calculate relative humidity.
Figure A. Liquid Thermometer. Figure B. Figure C. Figure D. Figure E. Figure F. Why is it important to measure atmospheric pressure? Figure G. Figure H. What is humidity? How is relative humidity measured? Figure I. Figure J.