Carbon neutral contribution and regional differences of clean energy based on life cycle assessment.

Developing clean energy is an important strategy to achieve global carbon neutrality. In the entire life cycle industrial chain of clean energy systems, fossil energy was directly or indirectly consumed during the processes from raw material production to waste disposal stages. The energy consumed by clean energy construction differed across regions, resulting in various carbon neutrality contributions of clean energy in different regions. We used bibliometrics to sort out the energy consumption of clean energy construction in different regions, including photovoltaic power generation, wind power, hydropower, and other clean energy sources. By combining the loss of land to decrease carbon pool during the operation of clean energy, we analyzed the current research hotspots, development status and trends, and difference in carbon emissions, and summarized the carbon neutral contributions of different regions. The intensity of clean energy carbon emission in China was significantly lower than global mean value. The average intensity of carbon emission in China in the four fields of onshore wind power, offshore wind power, hydropower, and photovoltaic power was 28.8%, 18.2%, 10.1%, and 16.7% lower than global average, respectively. For further research on carbon neutrality of clean energy, it is important to establish a unified life cycle assessment system, put forward construction strategies according to geographical differences, carry out ecological benefit evaluation for clean energy, and establish a clean energy transmission network system.

Connotation of urban ecological quality and the construction of its core index system.

Urban ecological quality is a necessary attribute for a healthy urban ecological state. In the period of urban development from large-scale incremental construction to stock improvement and quality transformation and incremental structural adjustment, there are many gaps between urban ecological quality construction and the requirements of the new stage. There is an urgent need to understand and integrate multiple needs, and construct an indicator system to promote the balance between supply and demand of ecological resources and efficient use to enhance urban ecological quality. We used the analysis methods of CiteSpace literature analysis, relevant policy collation and questionnaire survey to systematically sort out the key points of concern and differences in understanding among the three perspectives of science, government, and the public. The results showed that all the three perspectives, i.e., science, government, and public, were more concerned with indicators related to urban green space, gray infrastructure, and policy control. The concerns of science and public addressed indicators related to urban green space the most, while government being most concerned with indicators related to gray infrastructure. Based on those findings, we developed a core urban ecological quality index system with a total of 25 indicators, covering 10 major types of urban green space, environmental quality, gray infrastructure, and so on.

[Spatial distribution characteristics of carbon, nitrogen and phosphorous and pollution status evaluation of sediments in the Haihe River Basin, China.] / 海河流域水体沉积物碳、氮、磷分布与污染评价.

Studying the distribution of carbon, nitrogen and phosphorus of sediments on a whole-watershed scale is important to the research and management of water resources in the Haihe River Basin (HRB). In this study, total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) of 163 samples were investigated in the HRB. Based on these data, the pollution le-vels of sediments were assessed by using different quantitative indices. The results showed that the concentrations of TOC, TN, and TP in the HRB were heterogeneous at different locations. A decreasing trend of concentrations was found from downstream plains (e.g., the Beisihe River and the Heilonggang River) to mountain areas (e.g., the Yongdinghe River, the Beisanhe River, and the Luanhe River). In addition, the concentration of TOC in river sediments was higher than that of reservoir sediments. The statistical analyses showed that TN was significantly (P<0.01) correlated to TOC and TP, with a correlation coefficient of 0.704 and 0.250, respectively. The pollution level based on organic indices was classified as the clean level in the HRB. However, the areas with a relatively high pollution level were still found in some spots, such as the Beisihe River, and the Heilonggang River. Sediments of rivers and reservoirs were similar in the pollution intensity. The average C/N value of sediments in the HRB was 12.71, indicating that the TOC was derived from algae, phytoplankton flora and fauna, followed by higher plants. The C/N value of reservoir sediments was higher than that of river sediments, indicating that the contribution of terrigenous material inputs to TOC was larger in reservoirs than in rivers.

[Review on studies of anthropogenic heat emission.] / äººä¸ºçƒ­è®¡ç®—æ–¹æ³•çš„ç ”ç©¶ç»¼è¿°.

With the rapid development of metropolises worldwide, the urban heat island (UHI) effect is becoming a serious environmental problem in recent years. The rapidly increasing anthropogenic heat (AH) from human activities has more significant impacts on urban microclimate which aggravates the UHI effect. The characteristics of AH emissions at different scales may vary according to different natural backgrounds. Therefore, the calculation of AH is complicated and uncertain due to the temporal and spatial variation. This review presented different methods of AH calculation according to specific case studies at home and abroad. We summarized the scales of different methods and required data set as well as the certainty of error sources. Last we discussed the advantages, limitations, and potential improvements for different approaches. By the review, we suggested that the AH research should first choose a reasonable calculation method based on spatial and temporal scales to guarantee the accuracy. The calculation of AH could provide useful information to better understand the AH emissions of specific areas, which bring more potentials to improve the living environment through rational urban planning.

[Potential ecological risks assessment of heavy metals in the reservoir sediment of the western Haihe River basin].

The reservoirs distributed in the western part of Haihe River basin play a key role in drinking water supply in the densely populated region. The potential ecological risk of heavy metals stored in the reservoir sediments has drawn more attention during recent decades. In this study, a total of 10 reservoirs in the western Haihe River basin were sampled. The sediment samples were assessed by the Hakanson potential ecological risk evaluation index. The sediments of upstream and downstream rivers were also sampled for comparative analysis with those of the reservoirs. The results indicated the concentration of Cd was significantly higher than the background value in this region, it was 1.67 times of the background value on average and the highest was 2.77 times. The concentration of Pb was higher than the background value for more than half of the reservoirs. The potential ecological risk was evaluated by the toxic coefficient. The ecological risk level was decreased in the order of Cd>As>Pb>Ni>Cu>Cr>Zn. The ecological risk of Cd in most reservoir sediments belonged to a moderate harm. Xidayang Reservior, which supplied the drinking water for Beijing and Baoding, had the highest level of Cd pollution. The ecological risk of Cd in the upstream and downstream rivers was significantly higher than that of the reservoirs. In addition, the ecological risks of Pb, Cu and Ni in the upstream rivers were also higher than the reservoirs. The difference of ecological risks of Zn and Cr was not significant between reservoirs and rivers.

[Impacts of urban cooling effect based on landscape scale: a review].

The urban cooling island (UCI) effect is put forward in comparison with the urban heat island effect, and emphasizes on landscape planning for optimization of function and way of urban thermal environment. In this paper, we summarized current research of the UCI effects of waters, green space, and urban park from the perspective of patch area, landscape index, threshold value, landscape pattern and correlation analyses. Great controversy was found on which of the two factors patch area and shape index has a more significant impact, the quantification of UCI threshold is particularly lacking, and attention was paid too much on the UCI effect of landscape composition but little on that of landscape configuration. More attention should be paid on shape, width and location for water landscape, and on the type of green space, green area, configuration and management for green space landscape. The altitude of urban park and human activities could also influence UCI effect. In the future, the threshold determination should dominate the research of UCI effect, the reasons of controversy should be further explored, the study of time sequence should be strengthened, the UCI effects from landscape pattern and landscape configuration should be identified, and more attention should be paid to spatial scale and resolution for the precision and accuracy of the UCI results. Also, synthesizing the multidisciplinary research should be taken into consideration.

[Health assessment of river ecosystem in Haihe River Basin, China].

With the development of economy, the health of river ecosystem is severely threatened because of the increasing effects of human activities on river ecosystem. In this paper, the authors assessed the river ecosystem health in aspects of chemical integrity and biological integrity, using the criterion in water quality, nutrient, and benthic macroinvertebrates of 73 samples in Haihe River Basin. The research showed that the health condition of river ecosystem in Haihe River Basin was bad overall since the health situation of 72. 6% of the samples was "extremely bad". At the same time, the health situation in Haihe River Basin exhibited obvious regional gathering effect. We also found that the river water quality was closely related to human activities, and the eutrophication trend of water body was evident in Haihe River Basin. The biodiversity of the benthic animal was low and lack of clean species in the basin. The indicators such as ammonia nitrogen, total nitrogen and total phosphorus were the key factors that affected the river ecosystem health in Haihe River Basin, so the government should start to curb the deterioration of river ecosystem health by controlling these nutrients indicators. For river ecosystem health assessment, the multi-factors comprehensive evaluation method was superior to single-factor method.

[Ecological risk assessment of heavy metals in surface sediments in the southern and central Haihe River Basin].

Several heavy metals, including Cu, Zn, Cr, Ni, Pb, and Cd, were investigated at 80 sampling sites in the southern and central areas of Haihe River Basin. The spatial patterns and potential anthropogenic impacts of heavy metals were evaluated by several methods, such as the potential ecological risk index and enrichment factors (EFs). Results showed that, (1) The concentrations of heavy metals in the sediments were higher than the background values in most sites except for Cr, Ni. The concentration of Cd was 2.64 times higher than its background value. Based on the potential ecological risk index for single heavy metal, Cd in river sediments showed a high potential ecological risk while the other elements showed a slight potential ecological risk at most sampling sites. Generally, the decreasing order of the heavy metals was Cd > Cu > Pb > Ni > Cr > Zn. (2) The concentration of heavy metals in surface sediment varied in different regions. The concentration of heavy metals and the potential ecological risks were higher in the Ziya river (RI = 155. 64) and Daqing river (RI = 111.84) than those in the other rivers. For example, slight pollution of heavy metals was found in the Tuhai, Majia river (RI = 69. 54) and Heilonggang river (RI = 84. 50) due to a relatively low level of industrialization. (3) Cd, Pb, Zn, Cr were positively correlated with each other and might be derived from similar sources. The increasing order of anthropogenic impacts on heavy metals was Ni < Cr < Cu < Zn < Pb < Cd according to the calculated EFs. The anthropogenic impacts differed in different rivers. For example, strong impacts were found in the Ziya, Daqing, Yongding and Zhangwei rivers whereas weak impacts were showed in Tuhai, Majia and Heilonggang rivers.

[Regionalization of the freshwater eco-regions in the Haihe River Basin of China].

There is a growing concern about the ecological conditions in the Haihe River which have been profoundly impacted by the growing human population and intensifying development over the past several decades. By identifying the spatial characteristics of terrestrial and fluvial landscapes, we propose the guidelines and criterions for regionalizing the freshwater ecosystems in the Haihe River basin. The first-level and second-level zones reflect the spatial patterns of the natural backgrounds which could impact the surface water quantity and quality. The 6 first-level zones are regionalized according to topographic characteristics, runoff depth, annual precipitation and evaporation. They represent the spatial pattern of water resource quantity. The 16 second-level zones are regionalized according to the vegetation and soil types overlaid by the first-level zones. They represent the spatial patterns of eco-hydrological processes and water purifying functions of terrestrial landscapes. Finally, the eco-regions are evaluated by the field survey data including water quality, aquatic vegetation and zoobenthos communities. This study could potentially be used to guide the decision-making process for the management of water resources and local ecological projects in the Haihe River basin. The methods formulated in this research can possibly provide important references for other watersheds in China.

[Applicability of traditional landscape metrics in evaluating urban heat island effect].

By using 24 landscape metrics, this paper evaluated the urban heat island effect in parts of Beijing downtown area. QuickBird (QB) images were used to extract the landscape type information, and the thermal bands from Landsat Enhanced Thematic Mapper Plus (ETM+) images were used to extract the land surface temperature (LST) in four seasons of the same year. The 24 landscape pattern metrics were calculated at landscape and class levels in a fixed window with 120 mx 120 m in size, with the applicability of these traditional landscape metrics in evaluating the urban heat island effect examined. Among the 24 landscape metrics, only the percentage composition of landscape (PLAND), patch density (PD), largest patch index (LPI), coefficient of Euclidean nearest-neighbor distance variance (ENN_CV), and landscape division index (DIVISION) at landscape level were significantly correlated with the LST in March, May, and November, and the PLAND, LPI, DIVISION, percentage of like adjacencies, and interspersion and juxtaposition index at class level showed significant correlations with the LST in March, May, July, and December, especially in July. Some metrics such as PD, edge density, clumpiness index, patch cohesion index, effective mesh size, splitting index, aggregation index, and normalized landscape shape index showed varying correlations with the LST at different class levels. The traditional landscape metrics could not be appropriate in evaluating the effects of river on LST, while some of the metrics could be useful in characterizing urban LST and analyzing the urban heat island effect, but screening and examining should be made on the metrics.

[Recreational attraction of urban park wetlands in Beijing].

Taking the 20 urban park wetlands in Beijing as test objects, a 3-layer evaluation index system including urban park wetland landscape quality, location condition, and accessibility for the recreational attraction of urban bark wetlands was established, and, by using analytic hierarchy process (AHP) and an integrating index evaluation method, the recreational attraction of the urban park wetlands in Beijing was quantitatively assessed, and validated with questionnaire data. In Beijing, the urban park wetlands with high recreational attraction were in the order of the Summer Palace, Olympic Park, Qinglong Lake Park, Beihai Park, Yuanmingyuan Park, Yuyuantan Park, Shidu, Golden Sea Lake scenic area, Taoranting Park, and Yeyahu wetland. The Rice Fragrance Lake wetland and Zhenzhuhu scenic area had the lowest recreational attraction, and the others were fair. The evaluation results were supported by the questionnaire data, which indicated that the index system and evaluation model were useful. According to the recreational services, the 20 park wetlands in Beijing could be clustered into four categories, which could be managed in different ways. Appropriately assessing the recreational services of urban park wetlands could help the decision-making on the urban parks optimal planning and designing, improve human living environment, and optimize the spatial distribution of urban landscape.

[Correlating landscape pattern with total nitrogen concentration using a location-weighted sink-source landscape index in the Haihe River Basin, China].

Understanding the effect of land cover pattern on nutrient losses is of great importance in management of water resources. The extensive application of mechanism models is limited in large-scale watersheds owing to the intensive data and calibration requirements. On the other hand, the traditional landscape indexes only take the areas and types of land cover into account, considering less about their topographic features and spatial patterns. We constructed a location-weighted landscape index (LWLI) based on the Lorenz curve, which plots the cumulative proportion of areas for sink and source landscapes respectively against cumulative proportion of their relative location to the outlet in a watershed, including relative elevation, distance and slope. We assessed the effect of land cover pattern on total nitrogen losses in the Haihe River. Firstly, 26 watersheds were derived from 1: 250 000 digital elevation model (DEM), and their "source" and "sink" landscape types were identified from Landsat TM images in 2007. The source" landscapes referred to the paddy land, dry land and residential area, correspondingly the "sink" landscapes referred to the forest and grassland. Secondly, LWLI was calculated according to the landscape types and spatial patterns for each watershed. Thirdly, we accessed the effect of land cover pattern on total nitrogen (TN) flux according to the value of LWLI, comparing with the area proportion of sink-source landscapes. The correlation coefficients were different in three parts of Haihe River, i. e., 0.86, 0.67 and 0.65 in the Yanshan Mts, Taihang Mts and lower Haihe River. The results showed strong correlations between TN and LWLI in contrast to the weak correlations between TN and area proportion of sink and source landscape types. This study indicates the spatial pattern of land cover is essential for accessing the nutrient losses, and the location-weighted landscape pattern analysis may be an alternate to existing water quality models, especially in large watershed scales. The sink-source index is sufficiently simple that it can be compared across watersheds and be easily interpreted, and potentially be used in landscape pattern optimal designing and planning.

[Assessment of heavy metal pollution in surface sediments of rivers in northern area of Haihe River Basin, China].

Using Håkanson potential ecological risk index, the paper assesses heavy metal risk levels in northern parts of Haihe River basin based on 39 sampling sites. The results indicate that, the concentrations of Cu, Zn, Cd, and Cr in Haihe River basin are higher than the background values of heavy metals in China mainland, while the concentration of Pb is close to the background value in China mainland. Based on the potential ecological risk index for single heavy metal, the risk of Cu, Pb, Zn and Cr belongs to the "slight" level, while Cd has various risk levels at different sampling sites. Generally, the risk order of the heavy metals is Cd > Pb > Cu > Cr > Zn. According to Håkanson potential ecological risk index, 32 monitoring sites belong to "slight" level, 5 sampling sites belong to "middle" level, and 2 monitoring sites belong to "very strong" level. The most polluted sites are Tang River and Dashi River of Beijing, Juma River in Baoding. Therefore, these rivers should be taken more considerations in the river management.

[Analysis of seasonal variations of surface water quality in the middle and upper reaches of Wenyu River].

The middle and upper reaches of Wenyu River was chosen as a case study area, and the temp-spatial difference of surface water quality was systematically studied by water sampling from June to August of 2009. It was found that distinct seasonal variations was exhibited on surface water quality in the study area. In the mountain regions, TP, TN, NO3(-)-N, NH4(+) -N and TOC concentration in the water increase from June to July, and then decline remarkably, whereas the DO and COD concentration in the water display an opposite pattern. However, in the piedmont plains of Wenyu River middle reaches, TN, TP, PO4(3)-P and COD concentration decrease sharply from June to July and then increase substantially in August, while DO concentration shows a decline tendency from June to August. Furthermore, from the upper stream mountains to middle reaches of Wenyu river, self-purification capacity of surface water is reduced with its nutrient pollution aggravates, and the water pollution process and its formation mechanism are different. Altogether, the process of water pollution in the mountainous areas has a pulse pollution process in the rainy season, and the surface run-off in the rainy season may aggravate the pollution process by bring a large volume of non-point source pollutants into surface water from the land. Because of various types of pollution sources in the piedmont regions, the water pollution processes are unstable and peak surface run-offs in the rainy season may dilute the surface water pollutions. The results provide a scientific basis for ecological function regionalization.

[Dynamic changes of landscape pattern and eco-disturbance degree in Shuangtai estuary wetland of Liaoning Province, China].

The main objective of establishing natural reserve is to protect its natural resources from human disturbances and maintain its critical ecological service values. This paper introduced the concept of hemeroby, and by using remote sensing technology, systematically assessed the dynamic changes of landscape pattern and eco-disturbance degree in Shuangtai estuary wetland of Liaoning Province, China. Firstly, a knowledge-based expert system was used to classify the landscape into three first-level types based on eco-disturbance degree, i.e., undisturbed, partially disturbed, or completely disturbed, which were further classified into 30 second-level categories. Secondly, questionnaire and experts knowledge were adopted to determine the hemeroby index for each landscape type and to formulate a landscape classification system. Finally, the landscape classification maps and hemeroby indices were derived by using the Landsat Thematic Mapper (TM)/Enhanced Thematic Mapper Plus (ETM+) data acquired on 30 April 1987, 7 June 1995, 12 June 2000, and 11 October 2006. The results indicated that from 1987 to 2006, the landscape patches in the study area became more fragmented, being most obvious for reed marsh. Undisturbed landscape type decreased in area, while partially and completely disturbed types were in adverse. The overall characteristics of the spatial distribution of hemeroby index were of most variable in the areas along the river and surrounding the estuary and being the highest in the areas surrounding the city, largely due to the rapid urbanization and the blooming fishery in the study area.

[Assessment of freshwater ecosystem services in Beijing based on demand and supply].

Freshwater ecosystem provides a variety of services to humanity, and in return, human activities give strong stress on the services, particularly in urban area. It is of significance to study the impact of human occupation and stress on freshwater ecosystem. In this paper, a water equivalent method was used to calculate the human occupation on the freshwater ecosystem services in Beijing from 1998 to 2007, and assessed the human stress effect on the freshwater ecosystem, based on the total amount of water resources. In the past 10 years, the water equivalent of human activities in Beijing was about 5 to 17 times larger than the supply of the freshwater ecosystem. The water equivalent of the ecosystem services was decreased in the order of water environment purification > water resources supply > water habitat maintenance > water safety regulation. The gap between the consumption and the supply of freshwater ecosystem services had a trend of increasing to decreasing from 1998 to 2007, with the largest gap occurred in 1999. This study revealed that there was a huge gap between the consumption and the supply of freshwater ecosystem services in Beijing, which would inevitably result in the overloading occupation of the water resources in the City and give stress to the other regions.

[Vertical zonation of mountain landscape: a review].

Vertical gradient of mountain landscape is about 1000 times of its horizontal gradient, and hence, only using landscape pattern index is quite difficult to reflect the landscape regularity along vertical gradient. Mountain altitudinal belt is a kind of classic geographic models representing the vertical differentiation of landscape, being of significance in geographic and ecological researches. However, the discrete expression pattern and the inaccuracy of the borderlines of mountain vertical belts limit the roles of mountain vertical belt in accurately describing landscape pattern in regional scale and in explaining ecological processes. This paper reviewed the research progress and existing problems on mountain altitudinal belt, put forward a suggestion of using modern information technology to establish a comprehensive and continuous mountain landscape information chart, and discussed the framework and prospect of the establishment of the chart, which would have reference value for accurately describing mountain landscape pattern and explaining specific ecological processes, and promote the further improvement of the methodology for mountain ecological research.