Weather satellites are primarily used for monitoring the Earth’s weather and climate. They see more than clouds and cloud systems; they can also provide information about fires, city lights, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows, etc.
They have to be far away, at altitudes of 36’000 km in order for them to take pictures of the entire globe every 5 minutes.
Visible Satellite Images
Satellite weather images provide the information meteorologists use to monitor and predict severe storms, high clouds, vapor in the atmosphere, and even jet stream winds. They come in many shapes and sizes, from global composites that resemble snapshots of the Earth from space to tight close-ups of thunderstorm tops.
Visible satellite images depict cloud cover by measuring the amount of solar radiation the clouds reflect. As Table 1 shows, thick clouds and fresh snow reflect more light than thin clouds, so they appear brighter in the images. Thin clouds appear gray, and areas with no shading are generally clear.
Another type of satellite image, infrared (IR), measures cloud top temperatures instead of reflected light. Because temperature decreases with altitude, high-level clouds appear cooler in IR images than low-level ones. Middle clouds, meanwhile, have warmertops and appear in shades of gray.
Infrared imagery also reveals more details about rain and snow than visible satellites, since it can show the color of water vapor in the air. This can help pilots locate areas of heavy precipitation or ice buildup, as well as the direction and speed of rain.
Some IR satellites have special bands that detect wavelengths useful for identifying fog and low-level clouds at night. The National Weather Service in New Orleans tweeted an IR image from Monday night into early Tuesday morning that used the satellite’s night fog channel to reveal areas of foggy weather over the Gulf Coastal Plain and along the coast of Texas.
You can also determine the temperature of dark surfaces, such as trees and oceans, by looking at infrared images. This is a handy tool to have on hand when you’re trying to decide whether it’s safe to fly in a particular area.
The visible and infrared images also make it easier to see thunderstorms, which can be dangerous during daylight hours. Figures 1 and 2 illustrate this by showing cumulonimbus clouds (thunderstorms) that are visible in both types of imagery.
Another way to use a visible image is by using its albedo, or reflectance, to distinguish between cloud cover and snow cover. Thick clouds, such as cumulus and cirrus, have higher albedos than snow cover and can be seen more clearly on visible satellite images.
Infrared Satellite Images
Infrared (IR) satellite images are useful at night because they can distinguish the tops of low clouds and fog that are usually very hard to see with visible imagery. These images can be interpreted by comparing the temperatures of high cloud surfaces with the temperature of ground surfaces in surrounding areas where the weather is clear.
Most infrared sensors can detect long wave radiation within a wavelength range of 10.3 to 12.6 micrometers, a band that is transparent to atmospheric gases and liquid water vapor. Using this information, we can determine the temperatures of cloud and water surfaces and the amount of water vapor in the atmosphere at various heights.
We can also interpret changes in the temperature of cloud tops and their movement as a way to predict how much precipitation might be falling at different levels. This information can help us make better weather forecasts.
Another important function of infrared satellite images is to identify small fair-weather cumulus clouds that may be appearing in visible satellite images. These small clouds are a common feature of summer thunderstorms and are easily visible in infrared and water vapor satellite images.
This is because they tend to be cooler than air near the earth’s surface, which is warmer than the upper atmosphere and absorbed by the satellite’s infrared sensors. This helps to distinguish these fair-weather cumulus clouds from larger, darker, more complex clouds that are not easy to see in infrared or water vapor imagery.
In addition, infrared imaging provides more detail than the visible image, which is why it’s often used to help predict rainfall amounts or the likelihood of tornadoes and thunderstorms. Infrared imagery also helps to provide a more accurate depiction of cloud structures, including cumulus and stratus types.
Infrared satellite imagery is based on the fact that infrared energy is emitted by objects and is not absorbed by the air. These infrared images display objects based on their temperature, with the land and sea surface being the warmest and the upper atmosphere or air being the coldest. This means that colder high clouds appear white, while warmer low clouds are gray or dark.
Radar images provide information about the weather by revealing areas of precipitation and wind. This information can be used for forecasts and warnings.
When a radar pulse strikes an object, like a raindrop or snowflake, it is scattered by the atmosphere in all directions and reflected back toward the radar. The radar’s computers measure the frequency change in this reflected signal and then convert it to a speed of the object, either toward or away from the radar. This information about wind is important for the National Weather Service since it helps us to predict the formation of tornadoes and is used to determine whether or not a storm is severe enough to require a Tornado Watch.
In addition to detecting precipitation, radars also can detect ground clutter (ground clutter is a result of echoes that come from the surface). This phenomenon occurs when the emitted beam of radar energy is refracted almost directly into the ground at a distance from the radar. The resulting “ground return” echoes show up as dark spots on the radar image.
Another radar feature is a “sea return” that occurs when the emitted beam of radar waves is refracted almost directly into ocean waves. These echoes are much less common than ground clutter, but are still detectable at certain sites situated on coastlines.
Using this information, we can create a radar deformation “picture” of the surface. The picture is created by measuring two radar images of the same area taken at different times from the exact same vantage point in space, and then comparing the two pictures. This allows us to see changes in the ground over time, and even small ground motions such as surface sinking or ground slippage.
When this information is combined with other data such as a storm’s base reflectivity, it can help us to understand the structure of a storm. The base reflectivity is a radar image that displays the echo intensity in dBZ (decibels of Z).
In addition to the base reflectivity radar, there are other kinds of radar images that can be used to detect storms. These include the Precipitation Type Radar, which identifies areas of rain, snow, or hail.
Weather forecasts are an important tool in predicting the future behavior of the atmosphere. These forecasts are made using data from a variety of different sources, including satellites. These forecasts can provide information on a number of different topics, including rain and snow.
One of the most important types of weather forecasts is a visual map. These maps show the temperature, cloud cover, wind and precipitation for a particular location. This gives a very clear and concise representation of the weather in that area.
These maps are typically made by looping together a series of satellite images taken at different times during the day. This is done to help forecasters understand what the conditions are like at a particular time and to make sure they have accurate forecasts for their area.
The visual map above was made by NOAA’s GOES-17 satellite on February 9. It was captured the same day that a storm came into the Pacific Ocean and brought heavy rain and snow to the West Coast.
This image was taken at 6:00 PM and shows several distinct cloud towering masses protruding from the Earth’s surface. It also shows how the structures are changing over time, which can be very helpful when analyzing a specific weather event.
Infrared and water vapor satellite images are another type of image that is very useful to meteorologists. These images are very similar to photos, but they have been processed in order to show the clouds as they are rather than just the way they look in the sky.
For example, if a low pressure system were to form in Wisconsin and cause thunderstorms, the visible and infrared images can tell you where these clouds are likely to be moving and what type of cloud structure they are formed out of. The infrared image can also show the jet stream and how it is affecting these clouds.
A new system recently launched by NOAA is able to gather more data from the atmosphere than previously. Specifically, the new system has 16 channels of data, which will allow NWS forecasters to make better predictions. This will allow them to track the weather more accurately and can lead to more precise marine and aviation forecasts, McCoy said. This will benefit the entire Pacific Northwest, she added.
It is now possible to monitor the weather from your phone or computer via satellites. These satellites provide invaluable data that can be used to forecast the weather and conduct impact studies.
Weather satellites are capable of capturing images at a range of wavelengths, including the visible and infrared. These images are then sent back to Earth station and analyzed by computers.
Clouds are an indicator of Earth’s weather and climate conditions. They have an impact on the global temperature and energy balance of the planet, as well as the local weather. Understanding them is essential if we are to preserve our environment.
There are many types of cloud, each with its own unique properties. Some clouds are thin and appear light-to-medium gray in visible imagery (Figures 6a and 6b), while some others can be thicker and reflect a lot of the incoming solar radiation.
Satellite images often show cumulus, stratus, and altocumulus clouds. These clouds consist of a mixture of water vapor, air particles, and other elements.
These cloud layers tend to form over low pressure areas. This happens because air parcels that are forced upward through low pressure areas cool down and condense to form clouds.
Satellite weather is affected by the type of cloud that forms. This affects how much sunlight reaches the Earth’s surface, and how much heat escapes to space. These clouds can also lead to the destruction of the ozone layer in the stratosphere.
Satellite imagery can also show nimbostratus clouds, which are often associated to active precipitation. Nimbostratus can be thick layers with a wide spread that look like low-level clouds but actually form in mid-level troposphere.
Nimbostratus clouds are often very cold and can cause icing. Because they can absorb significant amounts of heat from the ground and then release it as rain, snow, or other forms of heat.
Nimbostratus clouds can have a negative impact on the Earth’s climate. They can increase the Earth’s surface’s energy output, and can cause an increase in Earth’s temperature, which is bad news.
Satellites are becoming more useful tools for scientists to better understand cloud properties and how they react to weather and climate. In the near future, the EUMETSAT Meteosat Third Generation geostationary satellites as well as the Metop Second Generation Polar-orbiting satellites will be launched. This will allow scientists to unravel much of the mystery surrounding cloud formation.
Satellite weather is dependent on albedo. It is the measure of how much sunlight hits a surface, and how much is reflected back to space. This is an important part of the global climate system as it influences how much energy is absorbed on a planet’s surface and how many it can send into space.
The amount of albedo that reflects back into space is dependent on the spectral reflection properties of the surface and its location in the sky (zenith angles), as well as the atmospheric conditions. Local environmental factors such as the surface type, thickness, and wetness of the snow or ice can also affect the albedo.
Fresh snow, for example, has an albedo value of 80%. On the other hand, bare ice has an albedo at 40%
Scientists can track weather changes and monitor albedo using satellites such as MODIS or GLASS. These measurements can be used to identify rogue asteroids or understand how weather patterns change across the globe.
The surface’s albedo can also change as the clouds move in and out, and snow and ice melt and freeze. This can have a significant impact on how much sunlight gets to the ground and how warm it feels.
Satellite observations of the surface albedo can help scientists understand how Earth is changing. Albedo is a key factor in Earth’s equilibrium temperature, and heat balance.
Satellite albedo can be used for almost every purpose and is therefore very versatile. You can use it to determine where snow and ice are decreasing, see where large quantities of liquid water are stored on the ground, and even measure the amount oxygen in the atmosphere.
A research team has recently examined the albedo at Urumqi Glacier Number. 1., in China’s Qinghai–Tibet area, using satellite data. Satellite data can be used to calculate the average albedo of a glacier’s surface by a factor 0.03. This is a lot more accurate than the measured surface albedo.
Both on a large and small scale, temperature plays an important role in weather. It has an impact on weather fronts, tropical storms, urban heat island, and the global climate.
Satellites measure the radiances of various wavelength bands. Scientists use these bands to calculate the temperature of different areas of the atmosphere. These radiances result from the heat emitted by oxygen molecules within the atmosphere.
Satellites orbiting the Earth scan the atmosphere 8 times per second. Scientists then apply weighting functions to get information at different altitudes. This allows each satellite’s four channels (Advanced Microwave Sounding Unit channels 5, 7, and 9), to capture different atmospheric temperatures at different heights.
Although the surface temperature record is the best way to determine temperature changes on Earth, satellite records show some year-to-year variations. Some records have shown flat trends, while others show a warming trend. El Nino has also caused some significant year-to-year fluctuations.
Flatness in recent years is one of the most significant trends in satellite temperature records. This is despite the fact that temperatures continue to rise at surface.
Scientists have suggested that the flatness of the Earth is due in part to a lack data in remote regions, such as Antarctica or Africa. This includes missing data, technical errors, instrumentation changes, station movement, and human error.
Satellite temperature records are also affected by the system’s sensitivity to atmospheric contaminants. These include water droplets found in clouds or precipitation.
Satellite temperatures may not be as accurate as those found on the surface. This is particularly true for the lower atmosphere known as the troposphere.
Temperatures in the upper atmosphere, also known as the stratosphere are slightly more accurate. Because the stratosphere absorbs more heat from the sun than the troposphere, temperatures are slightly more accurate. Satellite measurements can sometimes be off by just a few degrees due to the sensitiveness of these instruments to contamination.
Satellite weather is incomplete without wind, which is the movement of air. It is used to analyze storm tracks and their intensity and for forecasting. NOAA’s Derived Motion Winds data product, generated from imagery from the GOES-West (GOES-East) satellites is the main source of satellite winds data. It provides a new measurement of wind every 15 minutes above CONUS and an hourly elsewhere.
When solar radiation heats certain parts of the Earth’s surface more than others, wind is created. The temperature of the air in hot areas is higher than that in colder areas. This pressure difference creates wind which moves in the same direction as the sun’s rays.
Satellite scatterometer instruments and radiometers on satellites provide the most precise measurements of surface winds. These instruments are used to measure winds strength over oceans and seas. The resulting wind speed can be calculated using the Bragg scattering method.
Contrary to cloud-motion wind data which is derived from visible satellite imagery, radiometer wind vectors and scatterometer wind signals are calculated from the ocean’s microwave radiation signals. These signals have similar wave lengths because they are absorbed water molecules.
These waves’ amplitudes and phases change with ocean temperature, so they are not always constant. It is therefore difficult to determine wind speed and direction across large areas.
There are many methods that can be used to determine the direction and speed of surface winds from satellite data. These include visible-imagery analysis and scatterometer observations of cloud motion from aircraft at cruise height and surface wind data derived using geostationary satellite imagery.
These measurements, which are used to measure sea surface winds, are often combined with scatterometer and radiometer data from satellites in order to create a blended product. These data are then combined into a global analysis.
Satellite winds are assimilated into hurricane track forecasts, which can be significantly improved over multiple seasons (see Table 3). The relative decreases in track error at 12 h and 72 hours are statistically significant at the 95% confidence level.
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