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ANDREW RUSSELL GERAINT VAUGHAN EMILY G. NORTON HUGO M. A. RICKETTS CYRIL J. MORCRETTE TIM J. HEWISON KEITH. A. BROWNING ALAN M. BLYTH 《地球,A辑:动力气象学与海洋学》2009,61(2):250-263
A narrow line of convective showers was observed over southern England on 18 July 2005 during the Convective Storm Initiation Project (CSIP). The showers formed behind a cold front (CF), beneath two apparently descending dry layers (i.e. sloping so that they descended relative to the instruments observing them). The lowermost dry layer was associated with a tropopause fold from a depression, which formed 2 d earlier from a breaking Rossby wave, located northwest of the UK. The uppermost dry layer had fragmented from the original streamer due to rotation around the depression (This rotation was also responsible for the observations of apparent descent—ascent would otherwise be seen behind a CF). The lowermost dry layer descended over the UK and overran higher θ w air beneath it, resulting in potential instability. Combined with a surface convergence line (which triggered the convection but had less impact on the convective available potential energy than the potential instability), convection was forced up to 5.5 km where the uppermost dry layer capped it. The period when convection was possible was very short, thus explaining the narrowness of the shower band. Convective Storm Initiation Project observations and model data are presented to illustrate the unique processes in this case. 相似文献
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CYRIL L. GEACH 《Geology Today》1986,2(1):16-20
Lamproitic rocks of Western Australia have produced significant amounts of diamond and have given rise to the world's largest diamond mine. This has led to a reappraisal of the relationship between diamond and its host rock as well as new exploration techniques in the search for diamond. Procedures for success follow a modelling system using the most modern methods available in the Earth-related sciences. 相似文献
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