Jianfeng He

Publications (7)6.58 Total impact

• Article: Interannual variation of rare earth element abundances in corals from northern coast of the South China Sea and its relation with sea-level change and human activities.

  Yi Liu, Zicheng Peng, Gangjian Wei, Tegu Chen, Weidong Sun, Jianfeng He, Guijian Liu, Chen-Lin Chou, Chuan-Chou Shen
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  ABSTRACT: Here we present interannual rare earth element (REE) records spanning the last two decades of the 20th century in two living Porites corals, collected from Longwan Bay, close to the estuarine zones off Wanquan River of Hainan Island and Hong Kong off the Pearl River Delta of Guangdong Province in the northern South China Sea. The results show that both coral REE contents (0.5-40 ng g⁻¹ in Longwan Bay and 2-250 ng g⁻¹ in Hong Kong for La-Lu) are characterized with a declining trend, which are significantly negative correlated with regional sea-level rise (9.4 mm a⁻¹) from 1981 to 1996 in Longwan Bay, 13.7 mm a⁻¹ from 1991 to 2001 in Hong Kong). The REE features are proposed to be resulted from seawater intrusion into the estuaries in response to contemporary sea-level rise. However, the tendency for the coral Er/Nd time series at Hong Kong site is absent and there is no significant relation between Er/Nd and total REEs as found for the coral at Longwan Bay site. The observations are likely attributed to changes of the water discharge and sediment load of Pearl River, which have been significantly affected by intense human activities, such as the construction of dams/reservoirs and riverbed sediment mining, in past decades. The riverine sediment load/discharge ratio of the Pearl River decreased sharply with a rate of 0.02 kg m⁻³ a⁻¹, which could make significant contribution to the declining trend of coral REE. We propose that coastal corals in Longwan Bay and similar unexplored sites with little influences of river discharge and anthropogenic disruption are ideal candidates to investigate the influence of sea-level change on seawater/coral REE.
  Marine environmental research 10/2010; 71(1):62-9. · 1.76 Impact Factor
• Article: A quasiclassical trajectory study for the N(4S)+O2(X 3Σg-)-->NO(X 2Π)+O(3P) reaction on the new 2A' and 4A' potential-energy surfaces

  Jianfeng He, Feng Chen, Jing Li
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  ABSTRACT: A quasiclassical trajectory study with the sixth-order explicit symplectic algorithm of the N(4S)+O2(X 3Σg-)-->NO(X 2Π)+O(3P) atmospheric reaction has been performed by employing the new 2A' and 4A' potential-energy surfaces reported by Sayós et al. [J. Chem. Phys. 117, 670 (2002)]. For the translational temperature considered up to 10 000 K, the larger relative translational energy and the higher rovibrational levels of O2 molecule with respect to the previous works have been taken into account, and a clearer database about the character of the total reaction cross section has been presented in this work. The dependence of microscopic rate constants on the vibrational level of O2 molecule at T=3000, 5000, and 10 000 K has been exhibited, and we can see that the values of log10 k(T,v,J) vary almost linearly with the vibrational level of O2 molecule. The thermal rate constants at the translational temperature between 300 and 10 000 K have been evaluated and compared with the experimental and previous theoretical results. It is found that the thermal rate constants determined in this work have a better agreement with the experimental data and can provide a more valid theoretical reference at the translational temperature considered for the title reaction.
  Chemical Physics 01/2006; 124(5):4303. · 1.90 Impact Factor
• Conference Proceeding: Analyses the relationship between urban dynamic change pattern of the Yangtze River delta and the ecological environment

  Jianfeng He, Dafang Zhuang
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  ABSTRACT: We are using multi-temporal remote sensing image: TM image to analyse the spatial and temporal urban dynamic change pattern of Yangtze River delta region in the past two decades. Combined with the social and economic database of China, we analyses the relationship between the urbanization and society, environment. The results imply that from end of 80' to 2000 year, the main land use change pattern is the cultivable farmland and forest area decreased rapidly, urban area increased quickly spatially to joint to each other. The power reason for this transform are the development of the third industry mainly including traveling, lots of foreign investment entering in this area, increase of urban population, and fluctuation of the agriculture produce price. Going with this change the ecological environment problem became serious.
  Geoscience and Remote Sensing Symposium, 2005. IGARSS '05. Proceedings. 2005 IEEE International; 08/2005
• Article: [Concentrations of metallic elements, N and S in Sabina chinensis cv. pyramidalis leaves along urban-rural roadways of Nanjing city].

  Yunlong Yin, Yongming Luo, Taolin Zhang, Jianfeng He, Jianhua Xu
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  ABSTRACT: This paper measured the concentrations of metallic elements, N and S in soils and Sabina chinensis cv. pyramidalis leaves along the urban-rural roadways (urban trunk roads, belt highway, and suburban roads) of Nanjing city, with botanical garden as un-traffic impacted reference site, and discussed the transfer of test elements among atmosphere, plant and soil, as well as the impact of traffic-related pollution. The results showed that the concentrations of Al, Fe, Mo, Zn, Cd, Pb, As and Cr in Sabina chinensis leaves were significantly higher along urban-rural roadways than at reference site, being most remarkable for Al, Fe, Mo and Zn. The positive correlations between soil and Sabina chinensis leaf Fe, Zn and As concentrations in road environment indicated that Sabina chinensis might be a good indicator plant of soil Fe, Zn and As. The correlations between soil and plant leaf Al, Mo, Cu, Pb, Cd and Cr concentrations were not remarkable, and thus, their high concentrations in Sabina chinensis leaf in road environment might be caused by air pollution. The concentrations of N and S in Sabina chinensis leaf were higher along urban trunk roads and belt highway than at reference site, while those along suburban roads were similar to the reference. There was a negative correlation between soil and plant leaf N, and a positive correlation between soil and plant leaf S. The N content in roadside soil was lower, while the S content was higher than the reference, indicating that the higher Sabina chinensis leaf N content in road environment might be caused by the NO(x) from exhaust gas emission, and the higher leaf S content should be come from soil.
  Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 06/2005; 16(5):929-32.
• Conference Proceeding: Using RS and GIS technique to monitor China urbanization development

  Jianfeng He
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  ABSTRACT: Rapidly urbanization can cause many serious social, environmental and ecological problems, so it is important to monitor urbanization in spatial distribution and dynamic change using RS and GIS technique. We use the 1:100000 resource and environmental dynamic vector database of China to acquire the 1KM grid urban land change data collection for decade from end of 80's to 2000 which captures all of the high resolution urban land use information by calculating area percentage for urban land use category within every 1KM grid cell. Based on this data, we analyzed the spatial relationship between the urban development and population, social economy, and nature environment status. In the result, some developing features and trends of Chinese urbanization were brought forward.
  Geoscience and Remote Sensing Symposium, 2004. IGARSS '04. Proceedings. 2004 IEEE International; 10/2004
• Source

  Available from: Guijian Liu

  Article: The decline of winter monsoon velocity in the South China Sea through the 20th century: Evidence from the Sr/Ca records in corals

  Yi Liu, Zicheng Peng, Tegu Chen, Gangjian Wei, Weidong Sun, Ruoyu Sun, Jianfeng He, Guijian Liu, Chen-Lin Chou, Robert E. Zartman
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  ABSTRACT: A modern massive Porites coral was collected from the Longwan Bay (19°20′N, 110°39′E) on the east coast of the Hainan Island, China. The coral was sectioned vertical to the growth axis into discs of double density-bands representing annual growth. The samples were analyzed for the Sr/Ca ratio by inductively coupled plasma atomic emission spectrometry. The history of winter sea-surface temperature (SST) is reconstructed using the Sr/Ca ratio in winter bands of corals. The winter SST at Xisha in the middle of the South China Sea (SCS) is weakly correlated with the instrument-measured winter monsoon velocity (WMV) with a correlation coefficient of 0.19. The winter SST data from corals at Longwan Bay, Hainan, in the northern SCS are moderately correlated with the WMV (r = 0.40). Interestingly we found that the difference of winter SSTs between the two sites (Xisha and Longwan Bay, Hainan) (the X–H index) is significantly negatively correlated with the WMV (r = − 0.73). This negative correlation may be related to the intrusion of the warm Kuroshio Current into the SCS through the Luzon Strait promoted by the strong northeastern monsoon winds in the winter. Using the relationship between our coralline data and observed WMV, the calculated winter monsoon velocity (WMVc) was obtained for 87 years. This data set in combination with the instrument-measured data between 1993 and 1998 generate a record of WMVc for a period of 93 years from 1906 to 1998. The WMVc in the 20th century shows significant interannual and decadal variability with a trend of persistent decline in the whole 20th century at the rate of decrease of − 0.02 (m/s)/a. The lowest wind velocity occurred during the last two decades of the 20th century. The WMVc has decreased significantly by about 30% from the early to the late of 20th century. The 20th century decline of winter monsoon velocity evidenced from the SCS coral records is consistent with the atmosphere–ocean general circulation models (AOGCMs) simulations for monsoon response to increasing temperatures. In addition, an obvious decline shift of WMV around 1976 can be seen in both instrumental and proxy records and it coincides with many other Pacific records. This shift is likely to correspond to a Pacific-wide change in the Pacific Decadal Oscillation occurring at the same time.
  Global and Planetary Change 63(1):79-85. · 2.93 Impact Factor
• Article: Instability of seawater pH in the South China Sea during the mid-late Holocene: Evidence from boron isotopic composition of corals

  Yi Liu, Weiguo Liu, Zicheng Peng, Yingkai Xiao, Gangjian Wei, Weidong Sun, Jianfeng He, Guijian Liu, Chen-Lin Chou
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  ABSTRACT: We used positive thermal ionization mass spectrometry (PTIMS) to generate high precision δ11B records in Porites corals of the mid-late Holocene from the South China Sea (SCS). The δ11B values of the Holocene corals vary significantly, ranging from 22.2‰ to 25.5‰. The paleo-pH records of the SCS, reconstructed from the δ11B data, were not stable as previously thought but show a gradual increase from the Holocene thermal optimal and a sharp decrease to modern values. The latter is likely caused by the large amount of anthropogenic CO2 emissions since the Industrial Revolution but variations of atmospheric pCO2 cannot explain the pH change of the SCS before the Industrial Revolution. We suggest that variations of monsoon intensity during the mid-late Holocene may have driven the sea surface pH increase from the mid to late Holocene. Results of this study indicate that the impact of anthropogenic atmospheric CO2 emissions may have reversed the natural pH trend in the SCS since the mid-Holocene. Such ocean pH records in the current interglacial period can help us better understand the physical and biological controls on ocean pH and possibly predict the long-term impact of climate change on future ocean acidification.
  Geochimica et Cosmochimica Acta.