Is the weather information on Google Earth timely in cloud update?

The meteorological cloud pictures that Google sees on the earth are changing in real time. However, sometimes due to network or server problems, locally downloaded cloud images may be lost or not timely. Generally, there will be a new cloud image every half hour to 1 hour. I have to admire the technology of Google and its partners, which allows us to see the timely data and images of the earth's atmosphere almost in real time.

The meteorological part of GOOGLE EARTH mainly includes the following three contents.

1, cloud

Since the 1960s, observing cloud patterns on the Earth from space mainly depends on two kinds of environmental satellites: geostationary orbit satellites and near-earth orbit satellites. At least five geostationary satellites distributed on the equator can describe the global meteorological model updated every hour. The geostationary orbit satellite is located in a favorable position of 36,000 kilometers above the equator, but the on-board sensors cannot "see" the high latitudes near the north and south poles. LEO satellites usually fly over high latitudes over the North and South Poles every 90 minutes, so the images it takes can well complement the images of geostationary satellites, thus providing images covering the whole world. Even so, because each satellite observation represents a "snapshot" of the cloud type, the time of each snapshot is slightly different, and the underlying cloud itself is in constant movement and evolution, so this kind of satellite data merging work is very complicated.

In the description of global clouds, these satellite data are processed to distinguish clear (transparent) and cloudy areas. For cloudy areas, the brightness depends on the temperature difference between cloud top temperature and the ground, which is used to indicate the height of each cloud pixel. Low-level clouds such as stratocumulus and stratocumulus (fog) clouds are close to the surface, which may not display well.

A global cloud picture is a mosaic of observations made by 3-4 geostationary satellites. A satellite can't completely observe the earth at a certain moment, just as a camera can't photograph your face and the back of your head at the same time.

2. Radar

The radar images on Google Earth only cover the continental or offshore areas such as the United States, Canada and Europe, which is the limitation of ground-based radar data sources.

The radar image of Google Earth is provided by weather.com and the International Meteorological Administration (WSI) through a product called NOWrad.

NOWrad provides combined images of 14 1 taken by independent Doppler radar, which are maintained by the National Weather Service and the military. NOWrad composite image (or mosaic image) is updated every 5-6 minutes, and has been subjected to special computer software algorithm and strict quality control by meteorologists. Most quality control measures are used to identify and eliminate so-called non-meteorological targets.

3. Situation and forecast

That is, we often say weather forecast+weather reality.

Status quo-The status quo of Google Earth comes from weather.com, using the exclusive patented technology HiRAD (High Resolution Synthetic Data) of Weather Channel. HiRAD provides a highly localized, timely and accurate snapshot of the current meteorological conditions around the United States. HiRAD analyzes ground meteorological observation data and combines it with Doppler radar, meteorological satellite, lightning detection network, computer model of weather forecast and climate characteristics, providing unique and up-to-date meteorological conditions for 6,543,800 locations.

HiRAD system can really fill the gap in the current meteorological reporting system, which relies on the sparse weather station network distributed all over the country. Using a unique computer model, this technology can evaluate the meteorological conditions anywhere in the range of 1 mile with high quality, so that users can monitor and track the details of current meteorological conditions, such as current precipitation (such as rainfall, snowfall, fog and thunderstorms), cloud cover (such as partial cloudy and cloudy days) and visibility (which are important details when the weather conditions are snow or fog), which are usually not provided by other professional meteorological networks.

Forecast-The forecast data provided by weather.com is unique to the detailed weather forecast created by the Global Forecast Center (GFC) of the weather channel. GFC can generate forecasts for more than 65,438+07,000 different locations around the world (of which 65,438+00,000 locations are in the United States). Every global weather forecast is first created by a large and complex computer simulation program "DiCast". The first estimate or "guidance" is then sent to the forecaster, who fine-tunes and enhances the latest computer prediction results through a process called the forecast intervention period. After the intervention of meteorologists, the final forecast will be sent or released to all weather channel platforms and partners at the same time.