The thermal response of the tropical atmosphere to variations in equatorial Pacific sea surface temperature
The thermal response of the tropical atmosphere to variations in equatorial Pacific sea surface temperature
复制标题
DOI：
10.1029/jd094id12p14705
复制
发表时间：
1989-10
影响因子：
--
通讯作者：
G. Reid;K. Gage;J. R. McAfee
中科院分区：
文献类型：
--
作者：
G. Reid;K. Gage;J. R. McAfee
1966年至1982年期间，五个热带无线电探空站确定了从1000毫巴（0公里高度）到15毫巴（28公里）的30个压力水平的月平均温度异常，其中四个位于西太平洋（雅浦岛、马朱罗岛、威克岛和帕果帕果），一个位于加勒比海（库拉索岛）。数据中的长期趋势被删除，去趋势的时间序列与非季节性太平洋海面温度 (SST) 异常指数互相关，滞后范围长达 ±30 个月。在每个站点，相关图显示大气明显分为四个不同的区域，每个区域对海温变化都有不同的响应。在主对流层（850-150 mbar；2-14 km）中，相关性呈正相关，最大值滞后 1-4 个月，与早期研究基本一致。在平流层下层（100-40 mbar；16-22 km），相关性为负，具有类似的延迟，而表层（1000-850 mbar；0-2 km）和对流层上层（150-100 mbar；14-16 km）显示出不同站点的响应。在 40 毫巴（22 公里）以上，相关性基本降至零。对不同站的滞后的检查表明，对流层同相和平流层异相响应似乎从赤道中东部太平洋的明显原点以 1 m s−1 量级的速度沿纬向传播。讨论了这种传播背后的可能机制，并得出结论，来自对流活动中心的简单空气平流不太可能解释对流层和平流层响应。提出了另一种解释，涉及对流层沉降和平流层上升速率的变化以及伴随对流活动的变化。大气温度的长期趋势显示出随高度的变化，与海温相关性的变化平行。这可能表明大气正在对太平洋海面温度的相应长期趋势做出反应。
For the period 1966–1982, monthly mean temperature anomalies were determined for 30 pressure levels from 1000 mbar (0 km altitude) to 15 mbar (28 km) at five tropical radiosonde stations, four in the western Pacific Ocean (Yap, Majuro, Wake Island, and Pago Pago) and one in the Caribbean (Curacao). Long-term trends in the data were removed, and the detrended time series were cross correlated with an index of nonseasonal Pacific sea surface temperature (SST) anomalies with lags ranging up to ±30 months. At each station the correlation diagrams show a clear division of the atmosphere into four distinct regions, each having a different response to SST variations. In the main troposphere (850–150 mbar; 2–14 km) the correlation is positive, with a maximum at a lag of 1–4 months, in general agreement with earlier studies. In the lower stratosphere (100–40 mbar; 16–22 km) the correlation is negative, with a similar delay, while the surface layer (1000–850 mbar; 0–2 km) and the upper troposphere (150–100 mbar; 14–16 km) show responses that vary from station to station. The correlation drops essentially to zero above 40 mbar (22 km). Examination of the lags at the different stations indicate that the tropospheric inphase and stratospheric out-of-phase responses appear to propagate zonally from an apparent point of origin in the east central equatorial Pacific with a speed of the order of 1 m s−1. The possible mechanisms underlying this propagation are discussed, and it is concluded that simple advection of air from centers of convective activity is unlikely to explain both the tropospheric and the stratospheric responses. An alternative explanation involving variations in the rate of tropospheric subsidence and stratospheric upwelling accompanying variations in convective activity is suggested. The long-term trends in atmospheric temperature are shown to have a variation with height that parallels the variation in the SST correlation. This may indicate that the atmosphere is responding to a corresponding long-term trend in Pacific sea surface temperatures.