(Go: >> BACK << -|- >> HOME <<)

Help Glossary Home Help Glossary Home
 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

 Search Definitions
case sensitive
First Edition Preface  Second Edition Preface  Acknowledgments
Section KK index1-9 of 125 terms

previous1 2 3 4 5 6 7 8 9 10 11 12 13 Next

  • k–ε closure—A type of one-and-a-half-order turbulence closure that retains forecast equations for mean (first-order statistics) variables such as potential temperature and wind components, and also retains equations for variances (turbulence kinetic energy and temperature variance, symbolized by k) and for molecular dissipation or destruction of variances (symbolized by ε).
    Compare first-order closure, K-theory, second-order closure, nonlocal closure, Reynolds averaging, closure assumptions.
  • K bandSee radar frequency bands.
  • K changes—The K process is generally viewed as a recoil streamer or small return stroke that occurs when a propagating discharge within the cloud encounters a pocket of charge opposite to its own.
    In this view, the J process represents a slowly propagating discharge that initiates the K process. This is the case for K changes in cloud discharges. It is reasonable to expect that cloud discharge K changes are similar to the in-cloud portion of ground discharges.
  • K-indexSee stability index.
  • K index—(Also called George's index.) A stability index that is a measure of thunderstorm potential based on temperature lapse rate, moisture content of the lower troposphere, and the vertical extent of the moist layer.
    The K index is determined by the following equation:

    where T is the temperature and Td is the dewpoint in degrees Celsius at the pressure levels indicated. The higher (positive) the K index, the greater the likelihood of thunderstorm development.
  • K process—The return propagation of charge along a channel in a cloud in response to the initial breakdown streamer contacting a region of opposite charge.
    In this context it can be viewed as a small return stroke in the cloud. See K changes.
  • K-theorySee gradient transport theory, eddy viscosity.
  • K theory—(Also called mixing-length theory.) A method of describing the movement of trace species on the turbulent or subgrid scale.
    The theory relates the fluxes of the trace species to the gradient of the mean quantities via the eddy diffusivity (denoted K). See also turbulent flux.
  • kaavie—In Scotland, a heavy fall of snow.
  • kachchan—A hot, dry, west or southwest wind of foehn type in the lee of the Sri Lanka hills during the southwest monsoon in June and July.
    It is well developed at Batticaloa on the east coast, where it is strong enough to overcome the sea breeze and bring maximum temperatures of nearly 38°C.

    previous1 2 3 4 5 6 7 8 9 10 11 12 13 Next