对虾养殖生态系中有机碳的初步研究本研究由

对于围隔养殖对虾生态系中有机碳的变动进行了研究 ,结果表明 :溶解有机碳 (DOC)含量波动在 5 .2 99～ 13.39mg/ L之间 ,平均为 8.5 3mg/ L± 2 .2 5 mg/ L;颗粒有机碳 (POC)含量波动在0 .6 5～ 6 .6 3mg/ L之间 ,平均为 3.2 5 mg/ L± 1.76 mg/ L;总有机碳 (TOC)含量波动在 6 .92～ 2 0 .0 2mg/ L之间 ,平均为 11.78mg/ L± 3.82 mg/ L ;其中 DOC∶ POC∶ TOC为 0 .72∶ 0 .2 8∶ 1。各种有机碳组分的含量明显高于自然海水中各种有机碳的含量 ;各种有机碳组分的含量在养殖期间总体上呈上升的趋势 ;其变化与 DCOD的变化呈显著线性正相关的关系。     

Canonical Modelling of Relative Spacecraft Motion Via Epicyclic Orbital Elements

This paper presents a Hamiltonian approach to modelling spacecraft motion relative to a circular reference orbit based on a derivation of canonical coordinates for the relative state-space dynamics. The Hamiltonian formulation facilitates the modelling of high-order terms and orbital perturbations within the context of the Clohessy–Wiltshire solution. First, the Hamiltonian is partitioned into a linear term and a high-order term. The Hamilton–Jacobi equations are solved for the linear part by separation, and new constants for the relative motions are obtained, called epicyclic elements. The influence of higher order terms and perturbations, such as Earth’s oblateness, are incorporated into the analysis by a variation of parameters procedure. As an example, closed-form solutions for J₂-invariant orbits are obtained.     

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Scattering of Semidiurnal Internal Kelvin Wave at Step Bottom Topography

A three-dimensional, multi-level model was used to study the energy dissipation of semidiurnal internal Kelvin waves due to their interaction with bottom topography. A simplified topography consisting of a channel with an additional shallow bay was used to clarify the wave’s scattering process. When the first mode semidiurnal internal wave given at an open boundary arrives at the bay mouth, higher-mode internal waves are generated at a step bottom of the bay mouth. As a result, the energy of the first mode internal Kelvin wave is effectively decayed. The decay rate of the internal Kelvin wave depends on both the width and length of the additional bay. The maximum decay rate was found when a resonance condition occurs the bay, that is, the bay length is equal to a quarter of wave length of the first mode internal wave on the shallow region. The decay rate in the wide bay cases is higher than that in a narrow case, due to a contribution from the scattering due to the Poincare wave that emanates from the corners of the bay head. The decay rate with the additional bay is 1.1–1.8 times that of the case without the additional bay. The decay rate due to the scattering process is found to be of the same order as that of the internal and bottom friction.     

Intercalibration of Solar Soft X-Ray Broad Band Measurements from SOLRAD 9 through GOES-12

The two-band soft X-ray observations of solar flares made by the Naval Research Laboratory’s (NRL) SOLar RADiation (SOLRAD) satellites and by the Geostationary Orbiting Environmental Satellites (GOES) operated by the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center have produced a nearly continuous record of solar flare observations over a period of more than forty years (1969 – 2011). However, early GOES observations (i.e., GOES-2) and later (GOES-8 and subsequent missions) are not directly comparable due to changes in the conversion of measured currents to integrated fluxes in the two spectral bands that were adopted: 0.05 – 0.3 (or 0.4) nm, which we refer to as XS and 0.1 – 0.8 nm (XL). Furthermore, additional flux adjustments, using overlapping data sets, were imposed to provide consistency of flare-flux levels from mission to mission. This article evaluates the results of these changes and compares experimental GOES-8/GOES-2 results with changes predicted from modeled flare spectra. The factors by which recent GOES observations can be matched to GOES-2 are then optimized by adapting a technique first used to extrapolate GOES X-ray fluxes above saturation using ionospheric VLF radio phase enhancements. A nearly 20% increase in published GOES-8 XL data would be required to match to GOES-2 XL fluxes, which were based on observed flare spectra. On the other hand, a factor of 1.07 would match GOES-8 and later flat-spectrum 0.1 – 0.8 nm fluxes to GOES-2 XL if the latter data were converted to a flat-spectrum basis. Finally, GOES-8 observations are compared to solar soft X-ray estimates made concurrently with other techniques. Published GOES-8 0.1 – 0.8 nm fluxes are found to be 0.59 of the mean of these other determinations. Rescaling GOES to a realistic flare spectrum and removing a 30% downward adjustment applied to the GOES-8 measurements during initial data processing would place GOES-8 and later GOES XL fluxes at 0.94 of this XL mean. GOES-2 on the same scale would lie at about 0.70 of this mean. Significant uncertainties in the absolute levels of broad band soft X-ray fluxes still remain, however.     

Emergence patterns and microhabitat preference of aquatic dance flies (Empididae; Clinocerinae and Hemerodromiinae) on a longitudinal gradient of barrage lake system

Aquatic dance flies (Empididae; Clinocerinae and Hemerodromiinae) are important components of freshwater assemblages, especially in running waters. They are predators as larvae and adults and thus essential for understanding aquatic food webs. This study was conducted in Plitvice lakes National Park (Croatia) representing a wide variety of freshwater habitats (springs, streams, lakes and tufa barriers). Adults were collected monthly from March 2007 until March 2009 using pyramid-type emergence traps at 13 locations. A total of 3865 specimens comprising 18 species were collected. The dominant genus was Chelifera, while the most abundant species was Hemerodromia unilineata. All species were univoltine except Chelifera precabunda, Chelifera pyrenaica and Chelifera stigmatica that were bivoltine. Considerable differences in composition and structure of aquatic dance flies assemblages were recorded along a longitudinal gradient of studied sites, primarily related to differences in physical and chemical parameters of water. Water temperature was the main factor influencing the timing of emergence. Hemerodromia species preferred variable water temperature throughout the year while the majority of the Chelifera species preferred stable water temperature characteristic of spring sites. Furthermore, discharge affected assemblage composition of aquatic dance flies. The highest abundance of aquatic dance flies was recorded in lotic habitats with fast water current over substrates of moss, gravel and particulate tufa with detritus. These results give a new insight on microhabitat preference and their distribution on unique karstic habitats.     

微波爆发区的日冕磁场研究

回顾了日冕磁的研究历史，介绍了我们首镒提出的日冕磁场的微波诊断方法及其应用的带来的启迪，提出进一步开展日冕磁场及其相关研究的建议。     

利用GPS拖体在万山区域测量平均海面技术研究

Wanshan area has been chosen to be the specified field to calibrate and validate(Cal/Val) the HY-2 altimeter and its follow-on satellites. In March 2018, an experiment has been conducted to determine the sea surface height(SSH) under the HY-2 A ground track(Pass No. 203). A GPS towing-body(GPS-TB) was designed to measure the SSH covering an area of about 6 km×28 km wide centered on the HY-2 A altimeter satellite ground track. Three GPS reference stations, one tide gauge and a GPS buoy were placed in the research area, in order to process and resolve the kinematic solution and check the precision of the GPS-TB respectively. All the GPS data were calculated by the GAMIT/GLOBK software and TRACK module. The sea surface was determined by the GPS-TB solution and the tide gauge placed on Zhiwan Island. Then the sea surface of this area was interpolated by Arc GIS10.2 with ordinary Kriging method. The results showed that the precision of the GPS-TB is about 1.10 cm compared with the tide gauge placed nearby, which has an equivalent precision with the GPS buoy. The interpolated sea surface has a bias of –1.5–4.0 cm with standard deviation of 0.2–2.4 cm compared with the checking line. The gradient of the measured sea surface is about 1.62 cm/km along the HY-2 orbit which shows a good agreement compared with the CLS11 mean sea surface(MSS). In the Cal/Val of satellites, the sea surface between the tide gauge/GPS buoy and the footprint of altimeter can be improved by this work.     

粘土矿物对海水中主要营养盐的吸附研究

对海水中磷盐和硝酸盐在粘土矿物上的吸附行为的研究发现，海水体系中高岭土对磷酸盐的吸附能力大于蒙脱土，其原因为，粘土颗粒的表层铝／硅结构比是控制磷酸盐吸附的主要因素，其中铝含量越高，肿附能力越大。考察ＰＨ、粘土酸改性处理等因素对吸附作用的影响，结果表明，ＰＨ＜８．５的磷酸盐吸附ＰＨ曲线呈峰形，其吸附作用以阴离子交换为主；ＰＨ＞８．５时磷酸盐的吸附作用以沉淀吸附为主。酸改性蒙脱土可提高吸附磷酸盐的能力     

Lake Area Changes and the main causes in the hinterland of Badain Jaran Desert during 1973–2010, China

Lake area information in the Badain Jaran Desert in 1973, 1990, 2000, and 2010 was obtained by visual interpretation and water index analysis of remote sensing images, based on the spatial and temporal characteristics of lake area changes during 37 years. Results indicated that the number of lakes declined from 94 to 82 and the total surface area was reduced by 3.69 km² during 1973–2010. The desert lake area reduced by different degrees in different periods, but this occurred most rapidly during 1973–1990. According to the statistics of lake area changes, lake area decreases mainly occurred in the lakes with areas less than 0.2 km², while the areas of lakes greater than 0.9 km² only fluctuated. The changes of lake areas were probably due to changes in the quantity of underground water supplies rather than the effects of local climate change or human factors.