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指出积分型的位温守恒与熵守恒仅仅在绝热假设的条件下才是两个等价的积分型约束。对于非绝热大气，积分型的位温守恒代表位温算术平均值不变。热力熵的守恒等价于位温的几何平均值不变。这两者含义并不同，而且它们是不等价的。先前研究显示的位温服从Gamma分布表示大气同时满足位温的算术平均、几何平均守恒条件。因而我们建议在数值预告的非绝热模式中同时采用位温守恒与热力学熵守恒两个约束。 相似文献
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本文从统计物理学角度分析了气象学基本问题。指出气象学中的大气微团等元量可与统计物理中的基本研究对象粒子相对应。因而统计物理中的概念、方法和规律可以移植到气象学中来。文中定义了大气分布函数和大气的H函数,还研究了大气能量分布律和大气熵。文中综述了熵极值原理在气象上的应用并提出大气熵守恒猜想。最后指出如这一猜想被证实,则可以使中短期的数值天气预告的准确率明显提高。 相似文献
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根据绝热无耗散大气总动能和总位涡拟能守恒的特性，本文讨论了二维平面上动能谱分布随时间变化的规律。结果表明，大气谱动能变化必然涉及至少三种不同的空间尺度；或遵从双向转化原则，或遵从单向转化原则。在讨论能量的双向转化和单向转化条件的基础上，本文还分别研究斜压大气和正压大气中能量转化的一般状况。 相似文献
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本文通过使用Lagrange函数，导出了旋转大气中的广义Clebsch变换，并用广义的Clebsch变换求出了大气中的位涡和螺旋性守恒定理，然后再用Hamilton原理进一步讨论了大气中的位涡守恒定理，其结果是非常有意义的。 相似文献
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等熵位涡（简称IPV）的思想由于牵涉到两个守恒原理，除了它本身具有丰富动力意义外，还为我们在三维空间中找到了代表空气质块的物质线；因而，近来IPV的运用越来越受到人们的重视，在揭示了大气大尺度运动的机制当中，一些领域内已获得了新的进展。本试图对该方法作一系统的介绍。并对其研究进展作一个全面的评述。 相似文献
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湿位涡和倾斜涡度发展 总被引：266，自引：22，他引：266
从完整的原始方程出发，在导出精确形式的湿位涡方程的基础上，证得绝热无摩擦的饱和湿空气具有湿位涡守恒的特性。并由此去研究湿斜压过程中涡旋垂直涡度的发展。结果表明，在湿等熵坐标中，涡旋的发展与对流稳定度的减少，等熵面上的辐合和潜热的释放有关。由于等熵位涡分析的应用受等熵面倾斜的限制，又进而发展了Ｚ坐标及Ｐ坐标中的倾斜涡度发展理论。指出无论是湿对称不稳定或对流不稳定大气，还是湿对称稳定或对流稳定大气，除对流稳定度的影响外，风的垂直切变的增加或水平湿斜压的增加均能因湿等熵面的倾斜而引起垂直涡度的增长。湿等熵面的倾斜越大，这种由干湿斜压性加强所引起的涡旋发展更激烈。在梅雨锋附近及其南侧暖湿区的北端，湿等熵面十分陡立，是涡旋发展及暴雨发生的重要地区。对１９９１年６月１２—１５日江淮流域暴雨过程的湿位涡分析表明，湿位涡分析，尤其是等压面上湿位涡量ＭＰＶ１和ＭＰＶ２的分析不仅在中高纬有效，在低纬度及低对流层也十分有效，是暴雨诊断和预报的有力工具。 相似文献
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利用建立的球面分层大气散射模式，研究了Ｂｒｅｗｅｒ仪器工作波长进行Ｕｍｋｅｈｒ短法反演所包含的信息量，给出Ｂｒｅｗｅｒ仪器探测大气臭氧垂直廓线的方法。同时，用气溶胶光学厚度计算得到气溶胶订正系数，建立了Ｕｍｋｅｈｒ反演的程序，用此程序对ＴａｂｌｅＭｏｕｎｔａｉｎ资料进行气溶胶修正，得到了较好的结果。对北京测站１９９１年１─３月资料进行由气溶胶造成的臭氧反演廓线的误差计算，结果表明，用常规反演方法得到的各层臭氧含量的误差与平流层气溶胶光学厚度有一近似线性的关系；进行气溶胶修正后，与国外的臭氧反演廓线的误差修正工作￣［１］比较，结果较一致。研究提出的气溶胶订正反演方法为更好地对平流层臭氧变化趋势进行研究提供了可能性和可靠的基础。 相似文献
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Liu Qijun Zheng Xiangdong Luo Chao Tang Jie Ding Guoan Li Xingsheng Zhou Xiuji 《Acta Meteorologica Sinica》1998,12(1):103-111
From October 1995 to August 1996.a total of 50 ECC(electrochemical concentration cell) ozonesoundings were made in Xining(36.43°N,101.45°E,2296 m ASL)to study the distribution and seasonal characteristics of ozone profile,and intercompare the Brewer Umkehr ozone profiles obtained at Waliguan Baseline Station over the Qinghai Plateau.It was demonstrated that(1) Umkehr produced estimates of the ozone comparing with ECC profiles were accurate to better than 25% in the 20-38 km altitude range,and where 23-33 km region was the most accurate,within about 15% of the ECC ozonesonde:(2)higher differences between Brewer Umkehr and ECC ozonesonde occurred in the troposphere and lower stratosphere;and ozone amounts were overestimated in Umkehr layers 1,2 and 3,and were underestimated in Umkehr layers 6 and 7 by Brewer Umkehr method. 相似文献
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R. D. Bojkov E. Kosmidis J. J. DeLuisi I. Petropavlovskikh V. E. Fioletov S. Godin C. Zerefos 《Meteorology and Atmospheric Physics》2002,79(3-4):127-158
Summary Umkehr observations taken during the 1957–2000 period at 15 stations located between 19 and 52° N have been reanalyzed using
a significantly improved algorithm-99, developed by DeLuisi and Petropavlovskikh et al. (2000a,b). The alg-99 utilizes new
latitudinal and seasonally dependent first guess ozone and temperature profiles, new vector radiative transfer code, complete
aerosol corrections, gravimetric corrections, and others. Before reprocessing, all total ozone values as well as the N-values
(radiance) readings were thoroughly re-evaluated. For the first time, shifts in the N-values were detected and provisionally
corrected. The re-evaluated Umkehr data set was validated against satellite and ground based measurements. The retrievals
with alg-99 show much closer agreement with the lidar and SAGE than with the alg-92. Although the latitudinal coverage is
limited, this Umkehr data set contains ∼ 44,000 profiles and represent the longest (∼ 40 years) coherent information on the
ozone behavior in the stratosphere of the Northern Hemisphere. The 14-months periods following the El-Chichon and the Mt.
Pinatubo eruptions were excluded from the analysis. Then the basic climatological characteristics of the vertical ozone distribution
in the 44–52° N and more southern locations are described. Some of these characteristics are not well known or impossible
to be determined from satellites or single stations. The absolute and relative variability reach their maximum during winter–spring
at altitudes below 24 km; the lower stratospheric layers in the middle latitudes contain ∼ 62% of the total ozone and contribute
∼ 57% to its total variability. The layer-5 (between ∼ 24 and 29 km) although containing 20% of the total ozone shows the
least fluctuations, no trend and contributes only ∼ 11% to the total ozone variability. Meridional cross-sections from 19
to 52° N of the vertical ozone distribution and its variability illustrate the changes, and show poleward-decreasing altitude
of the ozone maximum. The deduced trends above 33 km confirm a strong ozone decline since the mid-1970s of over 5% per decade
without significant seasonal differences. In the mid-latitude stations, the decline in the 15–24 km layer is nearly twice
as strong in the winter-spring season but much smaller in the summer and fall. The effect of including 1998 and 1999 years
with relatively high total ozone data reduces the overall-declining trend. The trends estimated from alg-99 retrievals are
statistically not significantly different from those in WMO 1998a; however, they are stronger by about 1% per decade in the lower stratosphere and thus closer to the estimates by sondes.
Comparisons of the integrated ozone loss from the Umkehr measurements with the total ozone changes for the same periods at
stations with good records show complete concurrence. The altitude and latitude appearances of the long-term geophysical signals
like solar (1–2%) and QBO (2–7%) are investigated.
Received April 12, 2001 Revised September 19, 2001 相似文献
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北半球中纬度地区上层臭氧变化的合成分析研究 总被引：1，自引：1，他引：0
应用逆转方法（C）,对北半球中纬度地区8个观测质量较好的O3地面站的近30年地面遥感逆转资料进行标准处理。采用合成分析方法,对中纬度带上层O3进行了分析研究,发现上层O3总的长期演变趋势较为平坦,仅80年代初及90年代初在36km以上层O3含量有突降现象。这可能与EL Chichon大火山焊发和Pinatubo大火山爆发有较大关系。此外。在上层O3含量的长期演变过程中,还可看到准11年周期,并证实28～36km层及36km以上层O3含量季节变化位相相反。本研究结果可能对南极O3洞的形成机制及近年来O3层变浅薄的机制的认识提供依据并产生影响。
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ＳｔｕｄｙｏｆｔｈｅＳｉｍｕｌｔａｎｅｏｕｓＰｈｙｓｉｃａｌＲｅｔｒｉｅｖａｌＭｅｔｈｏｄｆｏｒＭｅｔｅｏｒｏｌｏｇｉｃａｌＰａｒａｍｅｔｅｒｓｏｖｅｒｔｈｅＣｏｎｔｉｎｅｎｔａｌＰｌａｔｅａｕｏｆＣｈｉｎａ￥ＬｉＧｕａｎｇｑｉｎｇ；（黎光清）Ｄｏｎ... 相似文献
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The wind finding equations currently used to retrieve horizontal winds from Global Positioning System dropwindsonde wind measurements are derived based on a point object model in which the drag coefficient of the dropwindsonde is assumed to be a constant. The wind tunnel tests performed as part of this study showed, however, that the dropwindsonde aerodynamic coefficients vary appreciably with angles of attack. To investigate the impact of this finding, the dropwindsonde motion in a pseudo-stochastic wind field has been simulated using a motion model more sophisticated than the point object model. The results showed that, although the constant drag coefficient assumption is not supported by the wind tunnel test results, the wind finding equations still correctly calculate both the mean and the turbulence intensity profiles. In addition, a revised method to calculate the vertical wind was proposed based on the derivation of the improved motion model, which enhanced the accuracy of vertical wind estimates by including the real-time dropwindsonde drag coefficient and the dropwindsonde vertical acceleration into calculation. 相似文献
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Chuwei Liu Jianping Huang Fei Ji Li Zhang Xiaoyue Liu Yun Wei Xinbo Lian 《大气和海洋科学快报》2021,14(4):52-57
2020年,新型冠状病毒肺炎(COVID-19)在世界范围内迅速传播.为准确预测各国每日新增发病人数,兰州大学开发了 COVID-19流行病全球预测系统(GPCP).在本文的研究中,我们使用集合经验模态分解(EEMD)模型和自回归-移动平均(ARMA)模型对GPCP的预测结果进行改进,并对发病人数较少或处于发病初期,不... 相似文献