A Mesoscale Model of the Planetary Boundary Layer Over the Ocean

海洋上空行星边界层的中尺度模型

• 批准号: 8840301
• 负责人: David Rogers
• 金额: $ 13万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-03-15 至 1990-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8840301&HistoricalAwards=false
• 关键词: Mesoscale; Model; Planetary; Boundary; Layer

Those familiar with the weather off the California coast can attest to the variability of cloudiness. Sometimes a deck of strato-cumulus clouds may persist for hundreds of miles for hours or days. At other times such a layer of clouds may form and break up within a relatively short period of time. Cloud-top entrainment instability is the mechanism whereby a stratocumulus deck breaks up into scattered cumulus clouds. It is generally accepted that the onset of the process depends on the temperature and mixing ratio discontinuity across the inversion. That is, whenever the equivalent potential temperature difference is smaller than a critical value, the inversion is unstable and entrainment can occur freely. However, recent evidence suggests that despite this instability the cloud deck may remain solid. This requires that other mechanisms sustain the entrainment instability; some examples include turbulence within the cloud layer, coupling between the cloud and subcloud layers, and shear induced entrainment. Under this grant, Dr. David Rogers will study these physical mechanisms using a mesoscale model of the planetary boundary layer over the ocean. The results should increase our understanding of the evolution of marine stratocumulus.

那些熟悉加州海岸天气的人可以 证明了云量的可变性。 有时候一副 平流积云可能会持续数百英里数小时 或者几天 在其他时候，这样的云层可能会形成， 在相对较短的时间内解体。 云顶卷吸不稳定是一种 层积云甲板分解成分散的积云。 它 一般认为，这一过程的开始取决于 温度和混合比的不连续性 反演 也就是说，每当等效电势 当温度差小于临界值时， 反转是不稳定的，并且可以自由地发生夹带。 然而，在这方面， 最近的证据表明，尽管有这种不稳定性， 甲板可以保持坚固。 这就要求其他机制 维持夹带不稳定性;一些例子包括 云层内的湍流，云和 云下层和切变引起的卷吸。 根据本 格兰特，大卫罗杰斯博士将研究这些物理机制 使用行星边界层的中尺度模式， 海洋 这些结果应该会增加我们对 海洋层积云的演化