论文部分内容阅读
虽然自1972年就开始了赤道湍流的测量,但是,直到1984年在赤道太平洋水域及其附近所进行的广泛而系统的测量才使我们对湍流混合及其时间变化有了崭新的认识。湍流活动正如我们所预料的那样,是如此巨大;但是它随时间的变化,却远远超过预料之外,日变化尤其如此,夜间平均湍流动能耗散率是白天的一百倍。这种变化发生在温跃层以及混合层中。与之有关的一些问题是:(1)在什么纬度和经度上,以及在什么季节会出现这种周期日变化?(2)是什么引起了这种较长期的时间变化?是大气强迫作用还是通过赤道波的切变场调制?(3)内波起什么样的作用?(4)能否用理查逊数来使湍流作用参数化?如果可以的话,那么合适的尺度有多大?现在已经取得了参数化,有关这些问题的观测结果,并不能肯定地解决这些问题。现在就取得的一些证据展开讨论。
Although measurements of equatorial turbulence have started since 1972, the extensive and systematic measurements made in and around the equatorial Pacific waters in 1984 gave us a fresh idea of turbulent mixing and its timing. Turbulence activity is as huge as we expected; however, it varies far with time, especially on a diurnal basis, with night-time average turbulent kinetic energy dissipation rates being one hundred times greater than during the day. This change occurs in the thermocline and in the mixed layer. Some of the questions that are relevant are: (1) at what latitude and longitude, and at what season, does such a diurnal cycle change occur? (2) what causes this longer-term change in time or is it atmospheric forcing or (3) What role does the inner wave play? (4) Is it possible to parameterize the turbulence using a Richardson number? If so, what is the proper scale? Now that Obtained parameterization, the observations on these issues, and can not be sure to solve these problems. Some evidence now available to discuss.