Frontiers of Earth Science

ISSN 2095-0195

ISSN 2095-0209(Online)

CN 11-5982/P

2018 Impact Factor: 1.205

Cover Story   2013, Volume 7 Issue 3
   Online First

Administered by

, Volume 7 Issue 3

For Selected: View Abstracts Toggle Thumbnails
REVIEW ARTICLE
The calibration methods for Multi-Filter Rotating Shadowband Radiometer: a review
Maosi CHEN, John DAVIS, Hongzhao TANG, Carolyn OWNBY, Wei GAO
Front Earth Sci. 2013, 7 (3): 257-270.  
https://doi.org/10.1007/s11707-013-0368-9

Abstract   HTML   PDF (258KB)

The continuous, over two-decade data record from the Multi-Filter Rotating Shadowband Radiometer (MFRSR) is ideal for climate research which requires timely and accurate information of important atmospheric components such as gases, aerosols, and clouds. Except for parameters derived from MFRSR measurement ratios, which are not impacted by calibration error, most applications require accurate calibration factor(s), angular correction, and spectral response function(s) from calibration. Although a laboratory lamp (or reference) calibration can provide all the information needed to convert the instrument readings to actual radiation, in situ calibration methods are implemented routinely (daily) to fill the gaps between lamp calibrations. In this paper, the basic structure and the data collection and pretreatment of the MFRSR are described. The laboratory lamp calibration and its limitations are summarized. The cloud screening algorithms for MFRSR data are presented. The in situ calibration methods, the standard Langley method and its variants, the ratio-Langley method, the general method, Alexandrov’s comprehensive method, and Chen’s multi-channel method, are outlined. The reason that all these methods do not fit for all situations is that they assume some properties, such as aerosol optical depth (AOD), total optical depth (TOD), precipitable water vapor (PWV), effective size of aerosol particles, or angstrom coefficient, are invariant over time. These properties are not universal and some of them rarely happen. In practice, daily calibration factors derived from these methods should be smoothed to restrain error.

Figures and Tables | References | Related Articles | Metrics
RESEARCH ARTICLE
Skill-assessments of statistical and Ensemble Kalman Filter data assimilative analyses using surface and deep observations in the Gulf of Mexico
Zhibin SUN, Lie-Yauw OEY, Yi-Hui ZHOU
Front Earth Sci. 2013, 7 (3): 271-281.  
https://doi.org/10.1007/s11707-013-0377-8

Abstract   HTML   PDF (627KB)

A new data assimilation algorithm (Quasi-EnKF) in ocean modeling, based on the Ensemble Kalman Filter scheme, is proposed in this paper. This algorithm assimilates not only surface measurements (sea surface height), but also deep (~2000 m) temperature observations from the Gulf of Mexico into regional ocean models. With the use of the Princeton Ocean Model (POM), integrated for approximately two years by assimilating both surface and deep observations, this new algorithm was compared to an existing assimilation algorithm (Mellor-Ezer Scheme) at different resolutions. The results show that, by comparing the observations, the new algorithm out-performs the existing one.

Figures and Tables | References | Related Articles | Metrics
Jet-like features of Jiulongjiang River plume discharging into the west Taiwan Strait
Daifeng WANG, Quan’an ZHENG, Jianyu HU
Front Earth Sci. 2013, 7 (3): 282-294.  
https://doi.org/10.1007/s11707-013-0372-0

Abstract   HTML   PDF (923KB)

In-situ data from the summer cruise of 2010 in the west Taiwan Strait are used to study the spatial distribution of the Jiulongjiang River plume (JRP). The results show that in the 2 m layer, the JRP debouches into the west Taiwan Strait in the form of jets, with one branch through the Xiamen Bay (Xiamen JRP) and another through the channel between Jinmen and Weitou (JinWei JRP). Driven by the summer southwesterly monsoon, the upwelling-related Dongshan low temperature and high salinity water flows northeastward in the form of a jet as well. To a certain degree, the Dongshan low temperature and high salinity jet restricts the Xiamen JRP from spreading further offshore and drags the JinWei JRP northeastward at the same time. Meanwhile, a terrestrial dissolved organic matter (DOM) distribution model on the basis of molecular collision theory in thermodynamics and statistical physics is applied to analyze the Moderate Resolution Imaging Spectroradiometer (MODIS) turbidity data. The correlation coefficient of the theoretical model to the MODIS turbidity data reaches 0.96 (significant at a 95% level of confidence). The result clarifies the dynamic mechanism for the turbidity distribution characteristics. It is the salinity in macro-scale that plays a decisive role in the turbidity variability in the coastal water. This suggests that the satellite-derived turbidity data can be used as an indicator to show the spreading patterns of the JRP. Based on the turbidity data from 2003 to 2011, we conclude that there are four main spreading patterns of the JRP.

Figures and Tables | References | Related Articles | Metrics
A geospatial web portal for sharing and analyzing greenhouse gas data derived from satellite remote sensing images
Hao LIN, Bailang YU, Zuoqi CHEN, Yingjie HU, Yan HUANG, Jianping WU, Bin WU, Rong GE
Front Earth Sci. 2013, 7 (3): 295-309.  
https://doi.org/10.1007/s11707-013-0365-z

Abstract   HTML   PDF (1097KB)

Greenhouse gas data collected by different institutions throughout the world have significant scientific values for global climate change studies. Due to the diversity of data formats and different specifications of data access interfaces, most of those data should be first downloaded onto a local machine before they can be used. To overcome this limitation, we present a geospatial web portal for sharing and analyzing greenhouse gas data derived from remote sensing images. As a proof-of-concept, a prototype has also been designed and implemented. The workflow of the web portal contains four processes: data access, data analysis, results visualization, and results output. A large volume of greenhouse gas data have been collected, described, and indexed in the portal, and a variety of data analysis services, such as calculating the temporal variation of regionally averaged column CO2 values and analyzing the latitudinal variations of globally averaged column CO2 values, are integrated into this portal. With the integrated geospatial data and services, researchers can collect and analyze greenhouse gas data online, and can preview and download the analysis results directly from the web portal. The geospatial web portal has been implemented as a web application, and we also used a study case to illustrate this framework.

Figures and Tables | References | Related Articles | Metrics
Analysis for remedial alternatives of unregulated municipal solid waste landfills leachate-contaminated groundwater
Da AN, Yonghai JIANG, Beidou XI, Zhifei MA, Yu YANG, Queping YANG, Mingxiao LI, Jinbao ZHANG, Shunguo BAI, Lei JIANG
Front Earth Sci. 2013, 7 (3): 310-319.  
https://doi.org/10.1007/s11707-013-0374-y

Abstract   HTML   PDF (700KB)

A groundwater flow and solute transport model was developed using Visual Modflow for forecasting contaminant transport and assessing effects of remedial alternatives based on a case study of an unregulated landfill leachate-contaminated groundwater in eastern China. The results showed that arsenic plume was to reach the pumping well in the downstream farmland after eight years, and the longest lateral and longitudinal distance of arsenic plume was to reach 200 m and 260 m, respectively. But the area of high concentration region of arsenic plume was not to obviously increase from eight years to ten years and the plume was to spread to the downstream river and the farmland region after 20 years; while the landfill’s ground was hardened, the plume was not to reach the downstream farmland region after eight years; when the pumping well was installed in the plume downstream and discharge rate was 200 m3/d, the plume was to be effectively restrained; for leakage-proof barriers, it might effectively protect the groundwater of sensitive objects within an extent time range. But for the continuous point source, the plume was still to circle the leakage-proof barrier; when discharge rate of drainage ditches was 170.26 m3/d, the plume was effectively controlled; the comprehensive method combining ground-harden with drainage ditches could get the best effect in controlling contaminant diffusion, and the discharge rate was to be reduced to 111.43 m3/d. Therefore, the comprehensive remedial alternative combining ground-harden with drainage ditch will be recommended for preventing groundwater contamination when leachate leakage has happened in unregulated landfills.

Figures and Tables | References | Related Articles | Metrics
Evaluation of economic loss from energy-related environmental pollution: a case study of Beijing
Chen CHEN, Meirong SU, Gengyuan LIU, Zhifeng YANG
Front Earth Sci. 2013, 7 (3): 320-330.  
https://doi.org/10.1007/s11707-013-0360-4

Abstract   HTML   PDF (549KB)

With the growth of energy consumption, energy-related environmental pollution has become increasingly serious, which in turn causes enormous economic loss because of public health damage, corrosion of materials, crop yield reduction, and other factors. Evaluating economic loss caused by energy-related environmental pollution can contribute to decision making in energy management. A framework for evaluating economic loss from environmental pollution produced during energy production, transportation, and consumption is proposed in this paper. Regarding SO2, PM10, and solid waste as the main pollutants, economic losses from health damage, materials corrosion, crop yield reduction, and solid waste pollution are estimated based on multiple concentration-response relationships and dose–response functions. The proposed framework and evaluation methods are applied to Beijing, China. It is evident that total economic loss attributable to energy-related environmental pollution fluctuated during 2000–2011 but had a general growth trend, with the highest value reaching 2.3 × 108 CNY (China Yuan) in 2006. Economic loss caused by health damage contributes most to the total loss among the four measured damage types. The total economic loss strongly correlates with the amount of energy consumption, especially for oil and electricity. Our evaluation framework and methods can be used widely to measure the potential impact of environmental pollution in the energy lifecycle.

Figures and Tables | References | Related Articles | Metrics
Magnetic properties of Holocene core ZK9 in the subaqueous Yangtze delta and their mechanisms and implications
Yan LIU, Zhongfa HE, Zhanghua WANG
Front Earth Sci. 2013, 7 (3): 331-340.  
https://doi.org/10.1007/s11707-013-0375-x

Abstract   HTML   PDF (689KB)

We measured the magnetic properties of core ZK9 from the subaqueous Yangtze delta to examine the mechanisms and possibility of using magnetic proxies for the sedimentary environmental evolution controlled by the Holocene sea level. The results showed that low values of most magnetic parameters occurred and pyrite formed in the estuarine sediments during c. 10.5–8.4 cal ka BP, reflecting the predominant early diagenesis in a tidal-dominated depositional environment when the sea level rose rapidly. Sharp increases in the values of χARM (susceptibility of Anhysteresis Remanent Magnetisation), χARM/χ, χARM/SIRM (Saturation Isothermal Remnant Magnetisation) and HIRM (Hard Isothermal Remnant Magnetisation) occurred immediately above the transitional zone from estuarine to deltaic system of c. 8.4–5.9 cal ka BP, which imply accumulation of single-domain magnetite and anti-ferromagnetic minerals. These magnetic properties indicate the enhanced freshwater processes at the core site as a result of the relatively stable sea level and the associated delta progradation since c. 5.9 cal ka BP. Therefore, magnetic proxies of χARM and HIRM are useful to identify the maximum flooding surface. In addition, the intertidal-subtidal sediment of c. 13.2–10.5 cal ka BP had high values of χ, SIRM and HIRM, reflecting the features of a coastal environment. The sharp decline of the above parameters from c. 10.5 cal ka BP indicates possibly an event of rapid sea level rise.

Figures and Tables | References | Related Articles | Metrics
Improving energetics in an ideal baroclinic instability case with a Physical Conserving Fidelity model
Qi ZHONG, Qing ZHONG, Ziniu XIAO
Front Earth Sci. 2013, 7 (3): 341-350.  
https://doi.org/10.1007/s11707-013-0378-7

Abstract   HTML   PDF (949KB)

To improve the energetics in the life cycle of an ideal baroclinic instability case, we develop a Physical Conserving Fidelity model (F-model), and we compare the simulations from the F-model to those of the traditional global spectral semi-implicit model (control model). The results for spectral kinetic energy and its budget indicate different performances at smaller scales in the two models. A two-way energy flow emerges in the generation and rapid growth stage of the baroclinic disturbance in the F-model. However, only a downscale mechanism dominates in the control model. In the F-model, the meso- and smaller scales are energized initially, and then an active upscale nonlinear cascade occurs. Thus, disturbances at prior scales are forced by both downscale and upscale energy cascades and by conversion from potential energy. An analysis of the eddy kinetic energy budget also shows remarkable enhancement of the energy conversion rate in the F-model. As a result, characteristics of the ideal baroclinic wave are greatly improved in the F-model, in terms of both intensity and time of formation.

Figures and Tables | References | Related Articles | Metrics
Impacts of river impoundment on the riverine water chemistry composition and their response to chemical weathering rate
Yang GAO, Baoli WANG, Xiaolong LIU, Yuchun WANG, Jing ZHANG, Yanxing JIANG, Fushun WANG
Front Earth Sci. 2013, 7 (3): 351-360.  
https://doi.org/10.1007/s11707-013-0366-y

Abstract   HTML   PDF (564KB)

Currently, most rivers worldwide have been intensively impounded. River damming becomes a big problem, not only in inducing the physical obstruction between upstream and downstream, but also in destroying the natural continuity of river. But the discontinuity of water quality was often neglected, which presents a challenge to traditional river geochemistry research. To understand the changes in basic chemistry of water upstream and downstream of the dam, we investigated the Miaotiao River reservoirs in series in the Wujiang River Basin, and the Hongjiadu, Dongfeng Reservoir on the upper reaches of the Wujiang River. Chemical weathering rates were calculated using the water chemistry data of the reservoir surface and downstream of the dam, in each reservoir, respectively. The results showed that the difference between the chemical weathering rates calculated from reservoir surface water and water downstream of the dam was greater in reservoirs with a longer water retention time. In Hongjiadu Reservoir with the longest water retention time among the studied reservoirs, this difference reaches 9%. As a result, the influence of river damming, especially the influence of reservoirs in series, should be taken into account when calculating the chemical weathering rate of a river basin.

Figures and Tables | References | Related Articles | Metrics
Application of Basin Morphometry Laws in catchments of the south-western quadrangle of south-eastern Nigeria
A.O AISUEBEOGUN, I.C EZEKWE
Front Earth Sci. 2013, 7 (3): 361-374.  
https://doi.org/10.1007/s11707-013-0356-0

Abstract   HTML   PDF (510KB)

The relationship between process and form has been at the core of research in fluvial geomorphology. Form-process relationships of a natural river basin are strongly influenced by its hydrologic and sedimentologic processes as basin morphometric properties of length, shape, and relief, change in response to various hydrologic stimuli from the environment, but usually in line with well established laws. In the four river basins (Orashi, Otamiri, Sombreiro, New Calabar) examined in this study, however, empirical evidence does not conform neatly with theoretical postulates. Remarkable variations are noted in the morphometric properties of the catchments, when compared with established morphometric laws. The most varied in conformity are the Orashi and New Calabar basins, although the Sombreiro and Otamiri catchments also show some level of variation. Prime explanation for the morphometric and topographic non-conformity is caused by the nature of surficial material and the profoundly shallow relief of much of the study area, especially the alluvial flood and deltaic plains to the south and south-west of the study area.

Figures and Tables | References | Related Articles | Metrics
Zinc phosphate dissolution by bacteria isolated from an oligotrophic karst cave in central China
Hongmei WANG, Qiang DONG, Jianping ZHOU, Xing XIANG
Front Earth Sci. 2013, 7 (3): 375-383.  
https://doi.org/10.1007/s11707-013-0379-6

Abstract   HTML   PDF (463KB)

Biogeochemical processes are fundamental to sustain the ecosystem in subsurface caves, but to date they are still far from well understood. To investigate microbially mediated phosphorus and zinc cycles, we isolated three bacterial strains from the dripping water in Heshang cave, central China, identified as Exiguobacterium aurantiacum E11, Pseudomonas fluorescens P35, and Pseudomonas poae P41, respectively. Microbial capabilities in the dissolution of phosphorus-containing minerals were tested with zinc phosphate (Zn3(PO4)2) in batch culture at 30°C. A spectrophotometer, atomic absorption spectrum, and scanning electronic microscopy were used to measure the microbial growth, soluble Zn(II) concentration, and to observe the morphology of Zn3(PO4)2 before and after microbial dissolution. P. fluorescens and P. poae, the well-known phosphorus solubilizing bacteria (PSB), are observed to solubilize Zn3(PO4)2 with an efficiency of 16.7% and 17.6%, respectively. To our knowledge, E. aurantiacum is firstly reported in this study to dissolve phosphorous-containing minerals with a higher efficiency of 39.7%, expanding our understanding about the ubiquitous occurrence of PSB in natural environments. Aqueous Zn(II) concentration positively correlates with H+ activity, confirming the presence of acidification mechanisms widely exploited by PSB. Few itching pits were observed on the surface of Zn3(PO4)2 after microbial dissolution, inferring that microbial dissolution is not always associated with the direct contact with minerals. Even though the soluble Zn(II) concentration reached up to 370 mg/L in the system inoculated with E. aurantiacum E11, inhibition of microbial growth was not detected by spectrophotometer. Our laboratory data revealed the importance of microbially-mediated P and Zn cycles in the subsurface ecosystem.

Figures and Tables | References | Related Articles | Metrics
Flooding impact on the distribution of microbial tetraether lipids in paddy rice soil in China
Asma AYARI, Huan YANG, Shucheng XIE
Front Earth Sci. 2013, 7 (3): 384-394.  
https://doi.org/10.1007/s11707-013-0382-y

Abstract   HTML   PDF (534KB)

Isoprenoid and branched glycerol dialkyl glycerol tetraethers (GDGTs) lipids were studied in flooded and non-flooded paddy soil in Wuhan, central China, to examine the response of the GDGTs distribution to the soil flooding. Samples were collected before and after the soil flooding in four specific months. Both core (CL) and intact polar (IPL) GDGTs were quantified. Increase in the abundance of archaeol and caldarchaeol may be indicative of the occurrence of methanogens in the flooded soil. A negative correlation was observed between the ratio of IPL branched GDGT-IIa to GDGT-Ia and the soil pH. The rise of the soil pH in the acid soil is known to be controlled by the redox conditions resulting from flooding. Thus, the branched GDGTs distribution may be controlled by the water content in the paddy soil. In addition, we suggest that the anoxic conditions resulting from flooding may also control the abundance of branched GDGTs relative to crenarchaeol, which in turn results in the increase of branched and isoprenoidal tetraethers (BIT) values, the index for the terrestrial input to the marine sediments.

Figures and Tables | References | Related Articles | Metrics
12 articles