Grlevelx
Encyclopedia
Weather radar
Weather radar, also called weather surveillance radar and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, estimate its type . Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the...
data. It was put on the market in March 2005. It comes in three versions : GRLevel2 and GRLevel2Analyst for viewing Level II data of the National Weather Service
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...
raw data, GRLevel3 for viewing Level III type. Both viewers feature high speed, high quality displays with an intuitive user interface.
The software allows the user to look at live data and analyze it on spot. It is used by professionals outside the National Weather Service for general precipitation analysis, tornado detection and hurricane strength.
Grlevel2Analyst allows the user to take a 3D images of a precipitation in clouds, such as in supercell thunderstorms. Its integrated algorithms flag possible hail, tornado vortexes, and storm strength.
All GRS applications are written in multithreaded
Thread (computer science)
In computer science, a thread of execution is the smallest unit of processing that can be scheduled by an operating system. The implementation of threads and processes differs from one operating system to another, but in most cases, a thread is contained inside a process...
C++
C++
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
using the base Windows API
Windows API
The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces available in the Microsoft Windows operating systems. It was formerly called the Win32 API; however, the name "Windows API" more accurately reflects its roots in 16-bit Windows and its support on...
s.
Overview
NEXRAD
NEXRAD or Nexrad is a network of 159 high-resolution Doppler weather radars operated by the National Weather Service, an agency of the National Oceanic and Atmospheric Administration within the United States Department of Commerce...
Level II data (volumetric reflectivity and velocity data). Base reflectivity, base velocity, storm relative velocity, and spectrum width sweeps for all radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
tilts can be ingested. The display has high speed zooming and panning to allow the user a quickly focus on the area of interest.
GRLevel2 Analyst Edition is an advanced Nexrad Level II analysis application to produce a high quality volumetric display
Volumetric display
A volumetric display device is a graphical display device that forms a visual representation of an object in three physical dimensions, as opposed to the planar image of traditional screens that simulate depth through a number of different visual effects...
and several high resolution reflectivity-derived graphical products in addition to the standard Level II data products.
GRLevel3 is a Windows viewer for live NEXRAD Level III data from the NWS Radar Product Central Collection Dissemination Service (already produced 2D images). Many television meteorologists, storm chasers
Storm chasing
Storm chasing is broadly defined as the pursuit of any severe weather condition, regardless of motive, which can be curiosity, adventure, scientific exploration or for news professions/media coverage....
, and weather enthusiasts use this software to locate supercells, tornadoes, rain, and other weather phenomenon.
Algorithms
Reflectivity
In optics and photometry, reflectivity is the fraction of incident radiation reflected by a surface. In general it must be treated as a directional property that is a function of the reflected direction, the incident direction, and the incident wavelength...
data. In reflectivities, GR2 extract the height above ground of the highest elevation where they are greater than 18 dBZ (Echo tops), the vertically integrated liquid water content of clouds (VIL) and the VIL divided by the Echo tops which is an indicator of possible large hail. Further algorithm use environmental information about of 0C and -20°C heights, inputted by the user, to output an hail algorithm size. The algorithm uses any temp/height data within 48 hours of the volume scan time. If no recent data is found, it defaults to 10,000 ft and 20,000 ft for the heights.
The results are displayed with a high resolution of 1 km x 1° x 230 km grid with 256 data levels. There is an automatic extraction of the storm motion which is integrated in the algorithms for corrections.
System Requirements
GR2Analyst has significant system requirements:- Windows XPWindows XPWindows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
or above - DirectXDirectXMicrosoft DirectX is a collection of application programming interfaces for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. Originally, the names of these APIs all began with Direct, such as Direct3D, DirectDraw, DirectMusic, DirectPlay,...
9.0c - Graphics adapter with shader model 2.0 support but the 3D volume products are both CPU and GPU intensive, requiring fast a CPU and mid to high end graphics adapters.