| 近50年我国探空温度序列均一化及变化趋势 |
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| 引用本文： | 郭艳君,丁一汇.近50年我国探空温度序列均一化及变化趋势[J].应用气象学报,2008,19(6):646-654. |
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| 作者姓名： | 郭艳君 丁一汇 |
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| 作者单位： | 1.国家气候中心, 北京 100081 |
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| 基金项目： | 科技部国际合作项目"区域气候变化的监测、模拟和影响研究"
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中国气象局2007气候变化专项"我国高空温度和大气水汽变化研究"
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国家自然科学基金项目"我国西部自由大气零度层高度变化及其对冰冻圈的影响研究"
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| 摘 要： | 利用1958—2005年我国116个站探空温度序列研究了我国高空温度变化趋势。首先通过静力学质量控制和两相回归法对原始序列进行了均一化处理。我国探空温度序列存在明显的间断点, 间断点的订正对于序列的趋势影响较为显著。缺测率是影响我国探空温度序列应用性的重要因子, 也是区域平均趋势统计中台站取舍的指标, 减少台站总数会削弱我国对流层升温和平流层降温的变化趋势。分析表明: 70%作为最小资料有效率标准最为合理。为满足最小资料有效率, 选取92个站统计我国高空温度变化趋势的区域平均值。结果表明: 1958-2005年, 平流层下层和对流层上层降温, 对流层中、低层升温; 高空温度变化趋势与研究时段明显相关, 1958-1978年我国高空大气整层均为降温; 1979—2005年, 对流层中低层升温最为明显, 增暖的幅度随高度增加而减小, 400 hPa以上各层转为降温。对流层的升温始于20世纪80年代, 升温幅度与全球尺度的平均值有所不同。
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| 关 键 词： | 探空温度 均一化 变化趋势 |
| 收稿时间： | 2008-02-18 |
Homogeneity and Long-term Trend Analysis on Radiosonde Temperature Time Series in China During Recent 50 Years |
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| Guo Yanjun and Ding Yinhui.Homogeneity and Long-term Trend Analysis on Radiosonde Temperature Time Series in China During Recent 50 Years[J].Quarterly Journal of Applied Meteorology,2008,19(6):646-654. |
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| Authors: | Guo Yanjun and Ding Yinhui |
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| Institution: | 1.National Climate Center, Beijing 1000812.Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 1000293.Graduate University of Chinese Academy of Sciences, Beijing 100039 |
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| Abstract: | In order to study long-term trend of upper air temperature in China, radiosonde temperature time series during 1958-2005 at 116 Chinese stations are examined.Firstly, uncertainties in the time series caused by artificial errors and breakpoints are detected by quality control and homogenization procedure. Original radionsonde temperature time series at 7 levels are adjusted by employing hydrostatic and two-phase-regression (TPR) method.The identification results show significant discontinuities in the studied time series, especially in earlier period (1960s-1970s). Parts of the break points are documented by station' s metadata, which contributes to the changes of instrument model or method.Significant impact on long-term trends of original time series is caused by the adjustments which vary with different periods. The cooling trends in mid-upper troposphere during 1958-1978 are weakened by homogenization; also, cooling trends in lower stratosphere are enhanced and warming trends at 400 hPa and 500 hPa during 1979-2005 are weakened.Missing rate, as an important factor influencing the utilization of radiosonde temperature time series in China, is a reasonable index for sampling stations to assess regional average trend. Sampling by low missing rate (high data requirement) results in reduced number of potential stations. By analysis on averaged trend profile with different minimum data requirements (MDR), it is found that warming trends in low troposphere are enhanced and cooling trends in upper troposphere and low stratosphere are weakened by the decreasing number of stations in accordance with low missing rate or high M DR of stations. Critical maximum missing rate is suggested as 30% (MDR as 70%) for examining reliability of the time series. Averaged temperature time series in China are deduced by 92 radiosonde stations, which are selected by meeting maximum missing rate (or minimum data requirement by MDR).Homogenous radiosonde temperature time series show that trends of upper air temperature in China are generally consistent with that at global scale but with some discrepancies. During 1958-2005, atmospheric temperatures in China tend to decrease in the low stratosphere and upper troposphere, and increase in the middle and low troposphere. The trends of upper air vary with different periods. For 1958-1978, cooling trends in the entire atmosphere are similar to those at global scale. During 1979-2005, obvious warming occurs in the low and mid-troposphere; the amplitude of warming trend weakens with the increase of altitude and shifts to cooling trend above 400 hPa. Analysis on decadal averaged temperatures anomalies shows that cooling in low stratosphere has occurred since 1980s and enhances in 1990s and warming in midlow troposphere below 500 hPa has occurred since 1970s and significantly warming in the layer between 700 hPa and 300 hPa has occurred since 1980s. |
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| Keywords: | radiosonde temperature homogenization trend |
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