Effect of convection on the summertime extratropical lower stratosphere
Effect of convection on the summertime extratropical lower stratosphere
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DOI：
10.1029/2004jd005209
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发表时间：
2004-12-02
影响因子：
4.4
通讯作者：
Sherwood, SC
中科院分区：
文献类型：
--
作者：
Dessler, AE;Sherwood, SC
在夏季北半球中纬度地区，对地球底部附近的卫星和原位水蒸气和臭氧观测（theta 大约为 380-K 位温）进行了检查，重点是它们的水平变化如何受到深对流的影响。我们表明，夏季对流对这里的水蒸气收支有显着影响，但对臭氧收支影响很小。使用一个简单的模型，我们估计，与没有对流的情况相比，对流使 380 K 的模型温带水汽增加了 40%，但仅使模型温带臭氧减少了几个百分点。现场数据显示，这种对流注入至少发生在 390 K 左右。这增加了对流湿润空气可能等熵地传播到热带地区并在不穿过冷点的情况下上升到平流层的可能性。我们认为，至少在夏季，应该检查对流湿润的趋势，将其作为观察到的平流层下层水蒸气趋势的可能贡献因素。
Satellite and in situ water vapor and ozone observations near the base of the overworld (theta approximate to 380-K potential temperature) are examined in summertime northern midlatitudes, with a focus on how their horizontal variations are influenced by deep convection. We show that summertime convection has a significant effect on the water vapor budget here, but only a small effect on the ozone budget. Using a simple model, we estimate that convection increases model extratropical water vapor at 380 K by 40% but decreases model extratropical ozone by only a few percent, relative to what would occur without convection. In situ data show that this convective injection occurs up to at least similar to390 K. This raises the possibility that the convectively moistened air might travel isentropically to the tropics and ascend into the stratospheric overworld without passing through the cold point. We argue that trends in convective moistening should be examined as possible contributors to observed trends in lower stratospheric water vapor, at least during summer months.