Weather satellites provide an important observational tool for all scales of NWS forecasting operations. Having a global view, satellite data complements land-based systems such as radiosondes and weather radars.
This app offers a variety of world satellite views to give you an up-to-the-minute picture of Florida. It also has a future radar option that can help predict storm movement up to six hours in advance.
Visible Satellite Images
Weather satellites capture and transmit images on a regular basis. Generally, new observations are available every 5 to 15 minutes, depending on location. These can be a great way to get an idea of what is going on in the area, and can even be animated for quick and easy understanding.
The main function of a visible satellite image is to show the earth’s surface in a clear, crisp way, as well as any cloud cover that may be in the vicinity of the image. The image is essentially a single photograph, capturing everything that the satellite sees. The quality of the photo can vary from image to image, but the most accurate images are those that capture as much detail as possible.
Another feature of the VIS is its ability to tell us about the reflectivity, or albedo, of a particular surface. For example, fresh snow cover is very reflective and can be seen clearly in a VIS image. Similarly, a thick cumulonimbus cloud will be bright white on a VIS image.
A third type of satellite imagery is the infrared (IR) image. IR is a more comprehensive measure of the reflected and emitted radiation that comes from the earth’s surface and atmosphere. This includes a wide range of wavelengths, from the visible to near infrared spectrum.
It’s not just clouds that emit IR radiation, but other elements in the atmosphere as well, such as dust and gaseous particles. The IR satellite can measure these particles and infer their temperature by measuring the IR wavelengths that are emitted from them.
Although IR isn’t as useful for telling us about cloud thickness, it can still tell us a lot about the height and temperature of cloud tops. The IR image also displays other features such as wind speed and direction, temperature gradients between different layers of the atmosphere, as well as the distribution of water vapour in the air.
Finally, a multi-spectral image may be the best way to show the true colors of the planet. A combination of several bands can provide the most accurate representation of the earth’s surface, including spectral data from the VIS, IR, and WV channels. This is especially helpful when assessing changes in surface properties over time.
Infrared Satellite Images
Satellite imagery is a great tool for monitoring weather conditions and tracking storms. Images are updated every 5 to 15 minutes, depending on the location. They can also be animated to produce a minute-by-minute view of the area.
There are two main types of satellite images: visible and infrared (IR). Visible satellites use light to show the clouds in the sky while IR imagery uses temperature to display the cloud tops. Both are important for monitoring weather systems and forecasting, but IR is useful at night when the visibility of visible satellites is poor or not possible at all.
Infrared satellites use the infrared light emitted by water and ice to determine cloud top temperatures. This gives meteorologists a sense of how hot or cold the surface of the earth is and how much rain or snow there might be in the atmosphere.
Because IR satellites have lower resolution than visible satellites, detecting low clouds is sometimes difficult. But if you take a look at this video, you’ll see that IR satellites can pick out a number of very low clouds.
But the challenge is that these clouds have very similar temperatures to ground that doesn’t have any cloud cover, even if it’s only a few miles away. It’s very common for IR images to have lighter gray areas that appear to be cloudy, when in fact they are just warmer than the surrounding ground.
The best way to avoid this problem is by using data from different IR wavelengths. By subtracting the data from different wavelengths, you can extract only the low cloud fields that exist at night.
A case study compared the accuracy of rainfall estimates made by a system of satellite raingages and radar over an area of south Florida that was significantly smaller than a larger area (1.3×104 km2 vs. 1.1×105 km2), and found that the raingage-radar estimates agreed better with the satellite rain estimates than did the satellite estimates alone.
Despite these limitations, IR satellites have a wide range of applications, including monitoring weather systems and the amount of precipitation in the atmosphere. They can also help us predict the direction of hurricanes and tropical cyclones.
Base Reflectivity Images
The base reflectivity image is a display of the echo intensity (reflectivity) measured in dBZ (decibels). All WSR-88D NEXRAD Doppler radars produce a base reflectivity product at each elevation angle, or tilt, of the radar antenna.
This is a very useful tool for determining the location of thunderstorm outflow boundaries and strong synoptic frontal passages, as well as hail potential. In addition, it can also be used to monitor surface and upper level dust storms that may occur in arid areas.
Typically, a thunderstorm cell will have a core of strong echoes separated by lower echoes. Tighter gradients of reflectivity between the edge and core of the storm often indicate a stronger storm, with more significant rainfall.
Another important characteristic to note is the presence of a “Three Body Scatter Spike” (TBSS) that extends outward from the high reflectivity core along the radar beam. These spikes are an artifact that occurs when portions of the radar pulses are scattered back into the core, causing them to bounce off a low-reflectivity area and then be reflected off a higher-reflectivity area.
When these TBSS appear, they can often be easily spotted by pilots. This is because they generally appear as a 10-30 km long (
These echoes are a common feature of radar imagery and often represent precipitation that evaporated before it reached the ground. However, these echoes are not always easy to spot, as they can be masked by ground clutter within 25 miles of the radar.
For this reason, it is often helpful to view a composite reflectivity image alongside a base reflectivity image. A composite image will show the highest dBZ value within the range of the radar, whereas a base image will typically include both low and high dBZ values.
A composite reflectivity image will also include echoes from objects such as buildings and hills. These echoes are commonly referred to as “ground clutter” and are sometimes removed using mathematical algorithms.
In general, the higher the dBZ value of an echoe the more intense the precipitation that is present in the sample volume. A dBZ value of 45 or more dBZ generally indicates intense rainfall, and is almost always caused by thunderstorms.
Weather Radar
Weather radar is a satellite-based tool that can help forecasters see and analyze weather events before they occur. The system uses a large radar dish and an antenna that sends pulses of energy into the atmosphere to detect precipitation. These pulses bounce back and forth until they reach the radar processor. The data is then processed and analyzed to help meteorologists predict when and where storms will occur.
Weather Radar is a vital part of any weather forecasting strategy because it can detect dangerous weather, including hail, tornadoes and wind gusts. It also helps meteorologists and news stations keep viewers informed and prepared for severe weather.
The latest weather radar technology offers increased accuracy and faster results than ever before. This means that broadcasters can deliver more accurate and reliable information, which can earn trust and credibility with viewers to help keep them coming back.
This technology allows meteorologists to provide timely and accurate hourly “nowcast” weather reports. This can be the best way to determine when the arrival of a precipitation event is likely. However, this type of forecast only works well when the local weather fronts or large organized precipitation structures are moving regularly and without disappearing or forming in an irregular manner.
It is important for meteorologists to use weather radar data in conjunction with other weather sources such as satellite images and ground-based weather sensors. This can help the team ingest more data and better initialize this information for accurate short-range forecasts.
There are three main types of radars used by meteorologists: C-Band, S-Band and X-Band. Each radar band has its own specific use case, as well as its own advantages and disadvantages.
S-Band is the most commonly used radar because it has a longer wavelength that can penetrate through multiple bands of precipitation. This allows it to identify precipitation rates more accurately than the C-Band. Nevertheless, this band is susceptible to attenuation. This reduces the strength of the beam, which can prevent it from seeing precipitation beyond the first band.
C-Band is a less common radar that has a longer wavelength than S-Band and can penetrate through moderate to heavy bands of precipitation. However, this band is more sensitive to lighter particles than S-Band and does not recognize precipitation rates as accurately. Nonetheless, it is often less expensive than S-Band and can be more mobile than the X-Band.