A Climatology of Unstable Layers in the Troposphere and Lower Stratosphere: Some Early Results
A Climatology of Unstable Layers in the Troposphere and Lower Stratosphere: Some Early Results
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DOI：
10.1175/mwr-d-20-0276.1
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发表时间：
2021-05
影响因子：
3.2
通讯作者：
M. Geller;P. Love;Ling Wang
中科院分区：
文献类型：
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作者：
M. Geller;P. Love;Ling Wang
1-s分辨率的美国无线电探空仪数据进行了分析，不稳定层，其中的位温随高度的增加而降低，在对流层和平流层（LS）。注意排除由探测中的噪声引起的虚假不稳定层，并考虑到饱和层中水汽的不稳定影响。对热带外的怀俄明州的里弗顿和北卡罗来纳州的格林斯伯勒进行了详细分析，发现LS的年变化和日变化最大，年际变化最小。在协调世界时0000点发现里弗顿的LS中出现更多不稳定层，而在格林斯伯勒，LS中出现更多不稳定层是在协调世界时1200点，这与美国西部LS中出现更多不稳定层是在协调世界时0000点，而美国东部出现更多不稳定层是在协调世界时1200点的地理模式一致。在热带帕劳的科罗尔的情况是不同的，在LS的不稳定层出现的日变化和年际变化是最大的，与小得多的年度变化。在科罗尔，更频繁的不稳定层出现在LS出现在0000 UTC。此外，在科罗尔观测到，在12公里左右出现不稳定薄层的频率有一个“缺口”，在该高度出现厚层的频率很高。为所分析的两个中纬度台站和一个热带台站制作了直方图。对流层直方图的对数-对数斜率与早期结果合理一致，但LS直方图显示更陡的对数-对数斜率，与更薄的不稳定层和更少的厚不稳定层一致。一些无线电探空仪台站被排除在本分析之外，因为当无线电探空仪仪器发生变化时，不稳定层发生了显著变化。
The 1-s-resolution U.S. radiosonde data are analyzed for unstable layers, where the potential temperature decreases with increasing altitude, in the troposphere and lower stratosphere (LS). Care is taken to exclude spurious unstable layers arising from noise in the soundings and also to allow for the destabilizing influence of water vapor in saturated layers. Riverton, Wyoming, and Greensboro, North Carolina, in the extratropics, are analyzed in detail, where it is found that the annual and diurnal variations are largest, and the interannual variations are smallest in the LS. More unstable layer occurrences in the LS at Riverton are found at 0000 UTC, while at Greensboro, more unstable layer occurrences in the LS are at 1200 UTC, consistent with a geographical pattern where greater unstable layer occurrences in the LS are at 0000 UTC in the western United States, while greater unstable layer occurrences are at 1200 UTC in the eastern United States. The picture at Koror, Palau, in the tropics is different in that the diurnal and interannual variations in unstable layer occurrences in the LS are largest, with much smaller annual variations. At Koror, more frequent unstable layer occurrences in the LS occur at 0000 UTC. Also, a “notch” in the frequencies of occurrence of thin unstable layers at about 12 km is observed at Koror, with large frequencies of occurrence of thick layers at that altitude. Histograms are produced for the two midlatitude stations and one tropical station analyzed. The log–log slopes for troposphere histograms are in reasonable agreement with earlier results, but the LS histograms show a steeper log–log slope, consistent with more thin unstable layers and fewer thick unstable layers there. Some radiosonde stations are excluded from this analysis since a marked change in unstable layer occurrences was identified when a change in radiosonde instrumentation occurred.