Comparison of two different solutions to Molodensky’s G1 term

The main purpose of this paper is comparison of two different approaches of solution to the Simple Molodensky’s Problem, the Molodensky’s Approach and the Analytical Continuation Approach, based on numerical computation. Although these approaches have been described theoretically by several authors, e.g. Molodensky et al. (1960), Heiskanen and Moritz (1967), Vaníček (1974), Moritz (1980) and Holota (1991, unpublished results) and theoretical proof of equivalence was given by Heiskanen and Moritz (1967), Moritz (1971), Ecker (1971) and Pellinen (1972, unpublished results), only very few practical experiences about the differences between particular solutions and computational efficiency exist. In this paper we compare the above two mentioned approaches in terms of the G₁-effect on quasigeoid. Both quasigeoid solutions are tested by the independent GPS/levelling approach and are also compared with the previous quasigeoid model of Slovakia where the G₁-term has been approximated using the classical terrain correction. The effect of the G₂-term is also numerically estimated, revealing that it might be significant for the precise quasigeoid determination. Some practical comments and recommendations are given at the end of the paper.     

A Study on the Relationship Among Visibility, Atmospheric Suspended Particulate Concentration, and Meteorological Conditions in Hong Kong

By making use of the 2005 hourly data of visibility at Chek Lap Kok and suspended particulate (PM2.5) at Tung Chung,PM2.5 concentration and visibility (excluding cases with mist,fog, rain, or relative humidity≥95%) are found to have a reciprocal relationship with correlation coefficient about 0.8. Besides, similar seasonal trends are exhibited in both the number of hours of reduced visibility (visibility below 8 km and excluding cases with mist, fog, rain, or relative humidity≥95%) and PM2.5 concentration, i.e., with higher value attained in winter and lower value in summer.Backward trajectory analysis using HYSPLIT indicates that this phenomenon is related to the source of air mass affecting Hong Kong. For continental trajectories, the average daily occurrence of reduced visibility and the daily mean PM2.5 concentration were much higher than the corresponding occurrence of reduced visibility and mean PM2.5 concentration for maritime trajectories.A case study on an event with a tropical cyclone approaching Hong Kong is included in this paper to demonstrate the significance of meteorological conditions in determining the visibility and PM2.5 concentration.     

遥感影像配准误差传递模型及模拟分析

在遥感影像配准过程中,通常假设控制点是“完美的”。然而,在实际情况中,由于控制点本身不可避免的带有一定的误差导致这种假设在一定情况下并不成立,并且将会影响遥感影像几何校正的精度。普通最小二乘方法OLS(O rd inary Least Square)是遥感影像配准常用的校正估计模型,令人遗憾的是,在控制点存在误差的情况下,它的估计是有偏的,并且不能够正确传递和估计校正影像的误差大小。引入一致校正最小二乘方法CALS(ConsistentAd justed Least Squares),在此基础上提出的一个改进的方法,称之为松弛一致校正最小二乘方法RCALS(Relaxed ConsistentAd justed Least Squares)。这类回归模型具有改正控制点(解释变量)中的误差和跟踪回归模型中的误差传递的能力。为了验证CALS和RCALS模型的有效性,本文利用模拟影像进行分析。这里着重分析OLS,CALS和RCALS模型在几何校正过程中的比较。结果表明,RCALS和CALS的结果优于OLS估计结果。     

Radioactivity and geochemistry of calc-alkaline neovolcanites of the West Carpathians

Summary The distribution of radioactive elements(Th, U, K) and selected trace elements(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) in a set of 29 volcanic rocks of the West Carpathians was studied. The rock types follow the typical calc-alkaline sequence from basaltic andesites to rhyolites with average contents of SiO₂, K₂O, Th, U, Rb, Ba and Zr increasing, and with average contents of TiO₂, Al₂O₃, FeO_t, MnO, MgO, CaO, P₂O₅, Sr, V, Cr and Ni decreasing from less to more acid rocks. Statistically significant differences in the contents of Th, U, Rb, Sr, Ba, Zr, K₂O, CaO and P₂O₅, found between the pyroxene andesites of Central and Eastern Slovakia, may indicate that the volcanism in both regions took place under different conditions. The andesites of Central Slovakia are characterized by relatively high contents of Th, U and Rb as opposed to the andesites from other volcanic areas, e.g., from the intraoceanic island arcs, the Andes or the Mexican volcanic belt.

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Резюме Иссле?rt;овaлось рaсnре?rt;еленuе рa?rt;uоaкmuвных(Th, U, K) u некоmорых ре?rt;кuх(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) элеменmов в нaборе 29 uзбрaнных вулкaнuческuх орных nоро?rt; с mеррumорuu Зana?rt;ных Кaрnam. Рaсnре?rt;еленuе uзучaемых злеменmов nре?rt;сmaвлено mрен?rt;aмu, nрuвычнымu ?rt;ля nоро?rt; uзвесmняк-щелочно о ря?rt;a. Сре?rt;нuе со?rt;ержaнuя SiO₂, K₂O, Th, U, Rb, Ba, u Zr nовыщaюmся, в mо время кaк со?rt;ержaнuя TiO₂, Al₂O₃, FeO_t, MnO, MgO, CaO, P₂O₅, Sr, V, Cr u Ni nонuжaюmся в нanрaвленuu оm основных к кuслым munaм орных nоро?rt;. Сmamuсmuческu знaчumельные рaзнuцы ?rt;ля со?rt;ержaнuŭ Th, U, Rb, Sr, Ba, Zr, K₂O, CaO u P₂O₅, нaблю?rt;aемые меж?rt;у руnnaмu nuроксеновых aн?rt;езumов ценmрaльноŭ u восmочноŭ Словaкuu, nокaзывaюm, чmо вулкaнuзм в эmuх облaсmях nрохо?rt;uл в рaзнообрaзных условuях. Ан?rt;езumы ценmрaльноŭ Словaкuu хaрaкmерны оmносumельно nовыщеннымu со?rt;ержaнuямu Th, U u Rb, коmорымu оmлuчaюmся оm aн?rt;езumов ?rt;ру uх ву лкaнuческuх облaсmеŭ, нanрuмер aн?rt;езumов внуmрuокеaнuческuх осmровных ?rt;у , южых Ан?rt; uлu Мексuкaнско о вулкaнuческо о nоясa.

     

Radioactivity and geochemistry of granulites and some related rocks from the saxonian granulite complex

Summary The distribution of radioactive(Th, U, K), major and selected trace(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) elements of granulites from the Saxonian Granulite Complex was studied. Similarly to the South Bohemian granulites, the Saxonian granulites can be divided according to the contents of their major and trace elements into two main groups, groupA containing mostly acid and subacid granulites (K ₂ O>2.5%, SiO ₂ >68%), and groupB containing mostly intermediate and basic granulites (K ₂ O<2.5%, SiO ₂ <68%). Statistically significant differences between groupsA andB were found for all major oxides and several trace elements(Rb, V, Cr, Ni). The Saxonian granulites follow the same calc-alkaline trend as the South Bohemian, granulitesA being placed mostly in the rhyolite field and granulitesB mostly in the dacite, andesite and basalt fields of this trend. The investigated granulites are characterized by a considerable scatter ofTh andU contents accompanied by very variableTh/U ratios; theTh andU concentrations of granulitesA are substantially lower than is usual for rocks of corresponding acidity.

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¶rt;a an¶rt;u a¶rt;uamu(Th, U, K) u ua ¶rt;u(Rb, Sr, Ba, Y, Zr, V, Cr, Ni) m aum n¶rt;a aaum na. naa, m u¶rt;aum n uu aam n aaum u ¶rt;u am aua, u u uu. aum n u uu ma a¶rt;um ¶rt; ¶rt;nn; nnA nua¶rt;ama a au¶rt; u au¶rt;aum (K ₂ O>2,5%, Si O ₂ >68%), nnB ¶rt;u u aum (K ₂ O<2,5%, SiO ₂ <68%). ¶rt; muunnau mm mamumuu m au ¶rt; a u u ¶rt; m ¶rt;u m(Rb, V, Cr, Ni). auaum n¶rt;¶rt;m um- m¶rt; a u -uaum;aumA a¶rt;ma a uum n, uaumB a a ¶rt;aum, a¶rt;um u aam n m m¶rt;a. ¶rt;aum — u unnA — aamum uu ¶rt;au da¶rt;uamu mTh uU.

     

IMPROVEMENTS OF A DISTRIBUTED HYDROLOGY MODEL DHSVM AND ITS CLIMATOLOGICAL-HYDROLOGICAL OFF-LINE SIMULATIONAL EXPERIMENTS

The advanced distributed hydrology-soil-vegetation model DHSVM,developed by Wigmostaet al.(1994)is introduced from US Pacific Northwest National Laboratory.To apply DHSVM inChina for the first time some improvements have been made in terms of the basin characteristics:1)to change evapotranspiration model,using the improved Penman-Monteith approach in place ofthe original one;2)to change the model structure,inserting datasets from 4 stations to grid cellsfor each river basin,instead of datasets from one or two stations;3)to develop new hydrology,vegetation and soil parameterization schemes for improving the simulated results,with focus oncalculation and adjustment of 11 parameters,such as soil porosity (?),field capacity θ_(fc),leaf areaindex LAI,stochastic resistance γ_s,among the total 33 parameters.Then the improved DHSVM isdriven by observed datasets for Luanhe River Basin and Sanggan River Basin,respectively.Thesimulated evapotranspiration(ET),runoff,snow water equivalent,water table,soil moisture andpercolation are then gained as DHSVM outputs.The simulated ET shows that the highest peakappears in May or June instead of July or August.This is consistent with the real situations,owing to the improvement of ET model.The simulated runoff process and flood peak are quiteconsistent with the observed ones.The model efficiency values for Luanhe River and SangganRiver Basins are 0.89 and 0.82,respectively,which shows high simulating ability of the modelsystem for both relatively humid and dry basins.