Variability and trends in the global tropopause estimated from radiosonde data
Variability and trends in the global tropopause estimated from radiosonde data
复制标题
DOI：
10.1029/2006jd007363
复制
发表时间：
2006-11-03
影响因子：
4.4
通讯作者：
Randel, William J.
中科院分区：
文献类型：
--
作者：
Seidel, Dian J.;Randel, William J.
本研究利用1980-2004年的无线电探空资料，在天气、月、季和年代际尺度上分析了全球对流层顶的变化。在天气尺度和月尺度上，对流层顶高度变化与平流层温度变化呈负相关，与对流层温度变化呈正相关。热带外的相关性强于热带，对流层上部（500-300 hPa）强于对流层下部，平流层下部强于平流层中部。对流层顶的月距平对平流层温度变化的敏感性高于对流层，平流层下部每冷却1 ℃，对流层顶高度月距平升高2-3 km。在1980-2004年期间，几乎所有分析的站点（主要是对流层外的站点）的对流层顶高度趋势都是向上的，估计全球趋势为64 +/- 21 m/decade，相应的对流层顶压力趋势为-1.7 +/- 0.6 hPa/decade，对流层顶温度下降为0.41 +/- 0.09 K/decade。这些对流层顶的趋势伴随着显着的平流层冷却和较小的对流层变暖。然而，对流层顶的趋势与平流层温度趋势在空间上相关，而与对流层温度趋势无关。对流层顶高度和平流层温度趋势的这种关联，以及对流层顶高度中存在的显著的准两年振荡信号，表明在这些最低频率下，对流层顶主要与平流层温度耦合。因此，作为气候变化的一个指标，对流层顶的长期变化可能比以前使用再分析和全球气候模式的研究所提出的关于整个垂直温度廓线变化的信息要少。
This study examines global tropopause variability on synoptic, monthly, seasonal, and multidecadal timescales using 1980-2004 radiosonde data. On synoptic and monthly timescales, tropopause height variations are anticorrelated with stratospheric temperature variations and positively correlated with tropospheric temperature variations. Correlations are stronger in the extratropics than in the tropics, for the upper troposphere (500-300 hPa) than for the lower troposphere, and for the lower stratosphere than for the middle stratosphere. The extratropical tropopause is more sensitive to temperature changes than the tropical tropopause, and in both regions, monthly anomalies of tropopause height are more sensitive to stratospheric temperature change than tropospheric, rising 2-3 km per degree cooling of the lower stratosphere. Tropopause height trends over 1980-2004 are upward at almost all of the (predominantly extratropical) stations analyzed, yielding an estimated global trend of 64 +/- 21 m/decade, a corresponding tropopause pressure trend of -1.7 +/- 0.6 hPa/decade, and tropopause temperature decrease of 0.41 +/- 0.09 K/decade. These tropopause trends are accompanied by significant stratospheric cooling and smaller tropospheric warming. However, the tropopause trends are spatially correlated with stratospheric temperature trends and uncorrelated with tropospheric temperature trends. This association of tropopause height and stratospheric temperature trends, together with the presence of a significant quasi-biennial oscillation signal in tropopause height, suggests that at these lowest frequencies the tropopause is primarily coupled with stratospheric temperatures. Therefore, as an indicator of climate change, long-term changes in the tropopause may carry less information about changes throughout the vertical temperature profile than has been suggested by previous studies using reanalyses and global climate models.