南极数值天气预报应用与研究进展

多个业务化的全球预报模式和有限区域预报模式应用于南极地区,已经成为南极天气预报和南极气候诊断研究的主要工具.现今南极地区的数值天气预报模式在模拟南极大气环流和天气系统方面性能不够理想,原因是多方面的:南极天气气候的特殊性(包括边界层的参数化、中尺度气旋等)、模式对南极复杂地形的描述不够充分、由于缺乏观测资料而使得模式的...     

The Spins of Astrophysical Systems and Extended Gravitational Theory

Recent data on the Tully–Fisher relation for spiral galaxies are compatible with the traditional correlation for astrophysical systems, where the angular momentum varies as the square of the mass. Such a correlation is consistent with standard gravitational theory, but is not explained by it. We here show that the noted relation follows from currently popular accounts of extended or higher-dimensional gravitational theory. The latter also predicts that the spins of spirals should decay as the universe expands, which can be tested by extending the Tully–Fisher data to higher redshifts.     

Meridional transport of sensible heat in contrasting monsoon activity: Spherical harmonic analysis

Spherical harmonic analysis is made of the grid point values of geopotential heights at 700 mb and 300 mb levels for the months April to August for the years 1967 and 1972. The year 1967 is a good monsoon year and 1972 is a bad monsoon year in India. Meridional transport of sensible heat is obtained in wave number domain using spherical harmonic coefficients at 500 mb level form=1 to 10 andn–m=0 to 10, wherem represents the wave number round the globe andn–m gives the numbers of zero points from north pole to south pole excluding the poles themselves.Large northward transports of sensible heat in the month of May and in the monsoon months at the subtropics are characteristic of bad monsoon. Wave 1 transports sensible heat southward (forn–m=0) and wave 2 transports sensible heat northward (forn–m=4). Strengthening of wave 1 is conducive to good monsoon year and strengthening of wave 2 is conducive to bad monsoon year. These are the same features obtained in Fourier analysis. The contrasting features exist in waves 1 and 2 both in good and in bad monsoon and are better defined in the present analysis than in the Fourier analysis of the earlier study. However, waves 1 and 2 reveal clearer contrast in the present analysis than in the Fourier analysis. Bad monsoon activity is associated with large divergence of heart at subtropics and large convergence of heat at extra tropics.     

莫高窟PM10浓度与气象要素的关系

采用2018年敦煌莫高窟第16窟窟内与窟区PM₁₀浓度及气象数据,分析PM₁₀时空分布特征及其影响因素。结果表明：（1）两处监测点PM₁₀浓度主要分布在50 μg·m^-3以下,受重污染天气影响较小;春、冬、秋、夏季依次降低,窟区PM₁₀浓度在春、冬季高于窟内,夏、秋季反之。（2）PM₁₀浓度3月最高,9月最低,5—9月窟内月均值高于窟区。PM₁₀污染日数窟内5月最多,而窟区3、5月较多。（3）PM₁₀浓度日变化曲线在春季和秋季呈“双峰”型,夏季和冬季呈“单峰”型。（4）在半封闭环境的洞窟内,沙尘暴发生前后,PM₁₀浓度达到极值及恢复至原来水平的时间均滞后于窟区。（5）在不同季节PM₁₀浓度与气温、风速和降水呈负相关。除秋季外,PM₁₀浓度与相对湿度、气压呈正相关。（6）窟区全年主风向为ESE,在冬春两季,此风向PM₁₀浓度最高,PM₁₀主要来自三危山前的戈壁滩、干涸的大泉河河道以及窟前裸露的地表积尘。     

Driving forces and their interactions of built-up land expansion based on the geographical detector – a case study of Beijing,China

Scientific interpretation of the driving forces of built-up land expansion is essential to urban planning and policy-making. In general, built-up land expansion results from the interactions of different factors, and thus, understanding the combined impacts of built-up land expansion is beneficial. However, previous studies have primarily been concerned with the separate effect of each driver, rather than the interactions between the drivers. Using the built-up land expansion in Beijing from 2000 to 2010 as a study case, this research aims to fill this gap. A spatial statistical method, named the geographical detector, was used to investigate the effects of physical and socioeconomic factors. The effects of policy factors were also explored using physical and socioeconomic factors as proxies. The results showed that the modifiable areal unit problem existed in the geographical detector, and 4000 m might be the optimal scale for the classification performed in this study. At this scale, the interactions between most factors enhanced each other, which indicated that the interactions had greater effects on the built-up land expansion than any single factor. In addition, two pairs of nonlinear enhancement, the greatest enhancement type, were found between the distance to rivers and two socioeconomic factors: the total investment in fixed assets and GDP. Moreover, it was found that the urban plans, environmental protection policies and major events had a great impact on built-up land expansion. The findings of this study verify that the geographical detector is applicable in analysing the driving forces of built-up land expansion. This study also offers a new perspective in researching the interactions between different drivers.     

First Data on the Isotopic Age of Zircons from Rocks of the Roseta Ultramafic Massif,Southern Margin of the São Francisco Craton (Brazil)

Doklady Earth Sciences - The results of isotope U–Pb dating of zircons from lherzolite and vein olivine orthopyroxenite composing the Roseta ultramafic massif are presented. The zircons...     

辽宁省海洋经济系统协调发展研究

通过构建海洋经济系统协调发展评价指标体系,采用模糊数学中隶属度函数模型,分析了辽宁省海洋经济系统发展水平及其协调发展度.结果表明:1999-2010年期间,辽宁省海洋经济、社会综合发展水平逐年递增,而资源环境综合发展水平值波动较大;1999-2003年,辽宁省海洋经济系统协调性处于失调状态,2004年之后大体处于协调发展状态,且协调等级逐步提升.     

The role of prior model calibration on predictions with ensemble Kalman filter

This paper, based on a real world case study (Limmat aquifer, Switzerland), compares inverse groundwater flow models calibrated with specified numbers of monitoring head locations. These models are updated in real time with the ensemble Kalman filter (EnKF) and the prediction improvement is assessed in relation to the amount of monitoring locations used for calibration and updating. The prediction errors of the models calibrated in transient state are smaller if the amount of monitoring locations used for the calibration is larger. For highly dynamic groundwater flow systems a transient calibration is recommended as a model calibrated in steady state can lead to worse results than a noncalibrated model with a well-chosen uniform conductivity. The model predictions can be improved further with the assimilation of new measurement data from on-line sensors with the EnKF. Within all the studied models the reduction of 1-day hydraulic head prediction error (in terms of mean absolute error [MAE]) with EnKF lies between 31% (assimilation of head data from 5 locations) and 72% (assimilation of head data from 85 locations). The largest prediction improvements are expected for models that were calibrated with only a limited amount of historical information. It is worthwhile to update the model even with few monitoring locations as it seems that the error reduction with EnKF decreases exponentially with the amount of monitoring locations used. These results prove the feasibility of data assimilation with EnKF also for a real world case and show that improved predictions of groundwater levels can be obtained.     

Numerical simulation of the interaction between two high-energy plasma bunches in the ionosphere

The 3D MHD algorithm developed by us has been adapted to modeling the interaction between two plasma bunches in the ionosphere, mainly in order to sufficiently correctly describe the physics of the interaction between two plasma regions with regard to the ionospheric inhomogeneity and the geomagnetic field action. Modeling has been performed for several versions of location of the plasma region centers.