Note: By your nature, radar images use color as a method of interacting information. This have the right to be a difficulty for people with shade vision deficiency. Visolve is a software application application (free for an individual use) the transforms color of the computer system display right into the discriminable colors for various human being including civilization with color vision deficiency, typically called shade blindness.

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Reflectivity photos are simply as lock sound together they paint a photo of the native the power reflected back to the radar. Reflectivity pictures are the vast majority of radar pictures you will see on television as well. There are two types available top top the web; Base Reflectivity (½° elevation) and also Composite Reflectivity.

Base Reflectivity

A base Reflectivity photo indicating precipitation.

Taken indigenous the shortest (½°) elevation scan, base reflectivity is excellent for surveying the an ar around the radar come look because that precipitation.

A base Reflectivity picture indicating precipitation.

This photo (right)(above) is a sample basic reflectivity image from the Doppler radar in Frederick, OK. The radar is situated in the center of the image.

The colors represent the stamin of returned energy to the radar expressed in values of decibels (dBZ). The color scale is located at the reduced right of every image. Together dBZ values boost so walk the soot of the rainfall.

Value the 20 dBZ is frequently the point at which irradiate rain begins. The worths of 60 to 65 dBZ is around the level whereby 1" (2.5 cm) diameter hail have the right to occur. However, a worth of 60 come 65 dBZ go not average that serious is arising at the location.

Severe may be emerging with values less (or greater) than 60 to 65 dBZ early out to...

Hail the is totally frozen (without a slim layer that water in the surface). "Dry hail" is a really poor reflector the energy and can result in an underestimate of a storm's intensity.Atmospheric problems such a ducting. As soon as ducting occurs, the radar beam is refracted into the ground (indicating more powerful storms 보다 what space actually occurring). However, a worse situation is as soon as subrefraction is occurring and also the beam is overshooting the most intense regions of storms (indicating weaker storms 보다 what are actually occurring).Doppler radars that gain out that calibration. The radar can come to be "hot" (indicating stronger storms 보다 what room actually occurring) or "cold" (indicating weaker storms 보다 what are actually occurring).The radar beam spreads through distance an interpretation the most intense component of the storm's reflect returns will certainly be averaged v the weaker portions causing an in its entirety appearance of reduced intensity.And, last but not least, the radar beam boosts in elevation together distance boosts from the radar.
At enhancing distance, the radar is viewing higher and greater in storms and also the beam might overshoot the most intense parts.

Composite Reflectivity

When every returns from all elevation scans space compiled an image is created which bring away the highest possible dBZ value from all elevations, called Composite Reflectivity. That is a photo of the the strongest returns from all elevations.

Composite Reflectivity look at at all elevation scans in bespeak to produce an image.

When compared with base Reflectivity, the Composite Reflectivity have the right to reveal crucial storm framework features and intensity trends of storms. This is important due to the fact that often during the development of solid to serious thunderstorms, rain-free locations (or locations with light rain) develop as a an outcome of solid updrafts.

Composite Reflectivity looks at all elevation scans in stimulate to produce an image.

Yet, due to the fact that it calls for all key scans to it is in completed, unequal the basic Reflectivity being the an initial image created, Composite Reflectivity is the last image produced in every volume scan.

Therein lies critical point when viewing composite reflectivity images; always check the time of the image. Often, the basic reflectivity image and also composite reflectivity photo will not have the same time through the base reflectivity picture being the many recent.

When compared with basic Reflectivity, the Composite Reflectivity can reveal necessary storm framework features and intensity fads of storms.

This is important since often during the advancement of strong to severe thunderstorms, rain-free areas (or locations with light rain) build as a result of solid updrafts.


In the loop (right)(below) that will adjust to the base reflectivity photo from the exact same time as the composite view. The very first thing girlfriend will notification about the composite photo is there is much much more "green" color near the radar, situated at the center.

When greater elevation scan info is had in the composite reflectivity, it appears to indicate more widespread rain.

However, the base reflectivity photo does not present that rain so the is probably not getting to the ground but evaporating as it falls from really high in the atmosphere.

Evidence that very solid updrafts (leading come the opportunity of serious can be seen as soon as comparing the 2 images. At #1, the fuchsia fancy region, clearly shows on the composite image, is every but missing on the basic reflectivity.

Remember the old adage "What go up, should come down", making use of the shade scale, this area is in ~ 65 dBZ top top the composite image. It is an area of issue as this is more than likely hail that has actually yet come fall. Part or many of the hail might melt before reaching the ground but at the really least, intense, blinding rain may be about to happen near this location.

The notches, at #2 and #3, show more rain sustained by strong updrafts. Those areas require extr interrogation to determine what is following at these places which will come native the velocity products.

One other note of caution, due to the time the takes come produce and transmit an image, every radar images show what HAS happened and also NOT have to WHAT IS happening.

Fast Facts

dBZ come rainfall price comparisondBZRain Rate(in/hr)Rain Rate(mm/hr)65605550454035302520
No rainNo rain

The dBZ values equate to almost right rainfall rates indicated at right.

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These room hourly rainfall rates only and also are no the actual quantities of rain a location receives. The total amount the rain received varies through intensity alters in a storm as well as the storm's activity over the ground.