ucar Highlights 2007

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Serving researchers based at universities and laboratories as well as its own staff, NCAR maintains a world-class fleet of facilities for observing and modeling the Earth system, from a powerful new aircraft to software that depicts the atmosphere in compelling detail

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Filling in the gaps | Tiny troubles in the air | Coding the atmosphere | A magnetic team |

Layering the atmosphere | A window on water vapor | A research aircraft is born

 
HIGHLIGHTS Multimedia

web iconREFRACTT - Refractivity Experiment for H2O Research and Collaborative Operational Technology Transfer

 

A window on water vapor

Four Doppler radars used refractivity data in 2006 and 2007 to track low-level moisture across northeast Colorado in unprecedented detail. REFRACTT, the Refractivity Experiment for H2O Research and Collaborative Operational Technology Transfer, depicted the pools of water vapor that slosh back and forth across the High Plains. Frédéric Fabry (McGill University) hatched the scheme behind REFRACTT while he was a postdoctoral researcher in NCAR’s Advanced Study Program during the mid-1990s. Fabry’s idea was to measure how changes in atmospheric moisture and density affect the speed of radar signals. The changes in signal speed are subtle, so the technique requires a fixed target—such as a silo or a power line—in order to determine how the signal speed varies across different weather conditions. The result is a map that shows water vapor (see illustrations) instead of blobs of rainfall or bundles of wind. The idea is to help pin down the locations where storms might start raging a few minutes to a few hours later. The technique could benefit researchers as well as the hundreds of forecasters who monitor thunderstorms and the public who relies on their storm warnings.
refractt

These images from northeast Colorado show how radar-derived refractivity data reveal the difference between moist and dry lower-level air (left vs. right), even when no rain is falling


Filling in the gaps |
Tiny troubles in the air | Coding the atmosphere | A magnetic team |

Layering the atmosphere | A window on water vapor | A research aircraft is born