By capturing photographic photos every 15 minutes, the satellites give continuous coverage of the western hemisphere. These "continuous eyes" are essential for detecting severe weather, snowstorms, tropical storms, and hurricanes. Every day, we go out to defend our lives and property, continuously on the lookout for new storms and severe weather. Satellites monitor these events and send warning messages to people who will be affected by them.
Satellites also provide information about climate change and other global issues that affect all of us.
Over the course of two weeks in May and June 2017, the Visible Infrared Imaging Radiometer Suite (VIIRS) on board NASA's Suomi NPP satellite collected visible and infrared light images of North America. The image above shows the portion of North America between Canada and Mexico at 10:30 p.m. Eastern Daylight Time on June 12, 2017. It is one in a series of images showing activity during the first week of summer across the continent.
The image was created using data from VIIRS which measures radiation in the visible light spectrum and near-infrared wavelengths beyond what humans can see. The photograph was taken within an hour of sunset because most volcanic eruptions occur shortly after midnight when there is less cloud cover over land areas.
One of the most powerful and crucial instruments utilized by meteorologists is satellite imagery. They are essentially the sky's eyes. These visualizations comfort forecasters about atmospheric behavior by providing a clear, simple, and accurate portrayal of how events are happening.
For example, when observing hurricanes from space, astronauts can see evidence of strong winds blowing away trees and buildings. This allows them to estimate with more accuracy how intense the hurricane will be when it reaches land.
Satellites also capture pictures of Earth's surface every day, which helps scientists understand how weather affects our environment and ourselves. For example, scientists can see how crops grow or fail based on whether they plant their seeds in soil that was recently exposed to drought or flood. They can also see how much carbon is stored in forests after a forest fire when they look at images taken by satellites flying over the fire site.
These examples show just some of the ways in which satellite data help meteorologists. They provide information about climate conditions, severe weather outbreaks, and environmental changes not available from any other source.
During severe weather outbreaks, geostationary satellites can be programmed to collect photographs every 5–15 minutes, focusing on smaller affected regions. On rare cases, geostationary satellites can be directed to snap a photo every minute, but only of a very narrow region, such as a violent thunderstorm. These images are used by meteorologists to identify and track severe weather formations and their movements across the landscape.
Other types of satellites also scan the earth's surface for signs of severe weather. They include:
Advanced Space-based Radar (ASR) systems use radio waves in the microwave range to map the subsurface structure of the earth with high resolution (less than 10 meters). The first ASR system was developed by the United States during the 1960s. Since then, other countries have followed suit with similar systems. Although these systems are capable of detecting severe weather formations deep under thick layers of soil or water, they are most effective when used in combination with other methods such as radar and satellites that provide information about the atmosphere above the storm center.
Lightning detection networks use satellite technology to monitor the movement of electricity through the air with high accuracy. Severe weather events such as tornadoes and hurricanes can be detected by these networks as they form over large areas. Lightning detection networks are currently operated by several companies including COWI (Canada), GeoSpark (Germany), Spire (USA), and SSC (Spain).
Every six hours, three polar-orbiting satellites may observe the whole world. This orbit allows for a closer look at the Earth, resulting in high-resolution photographs and data. Because these satellites are constantly moving, they cannot provide continuous surveillance of a specific geographical region.
How long will satellites stay in space? >7 years
After reaching their designed lifetime, older satellites are either destroyed in orbit or brought down using fuel to burn up in the atmosphere.
What is the advantage of having a satellite in space? > Remote sensing - measuring aspects of the environment from a distance, such as temperature, moisture, vegetation health, or ice cover> Military - providing intelligence, surveillance, and reconnaissance information for military operations> Communication - transmitting voice, video, or data between people on earth and aircraft, ships, or land vehicles> Weather - providing observations that help forecast changes in the weather> Science - collecting data on climate change, gravity, the moon, etc.
Disadvantages of satellites include cost (which increases with each launch), limited service life (typically 7-10 years), and difficulty in recovering them if lost.
Why are some satellites secret? > If something secret needs to be observed or recorded from a great distance, then a satellite is used. Satellites can see things on the ground that humans can't, like enemy forces and weapons sites.