Time filter

Source Type

Sun S.,Nanjing University of Information Science and Technology | Chen H.,Nanjing University of Information Science and Technology | Ju W.,Nanjing University | Song J.,Northern Illinois University | And 3 more authors.
Theoretical and Applied Climatology | Year: 2013

Hydrological processes depend directly on climate conditions [e. g., precipitation, potential evapotranspiration (PE)] based on the water balance. This paper examines streamflow datasets at four hydrological stations and meteorological observations at 79 weather stations to reveal the streamflow changes and underlying drivers in four typical watersheds (Meigang, Saitang, Gaosha, and Xiashan) within Poyang Lake Basin from 1961 to 2000. Most of the less than 90th percentile of daily streamflow in each watershed increases significantly at different rates. As an important indicator of the seasonal changes in the streamflow, CT (the timing of the mass center of the streamflow) in each watershed shows a negligible change. The annual streamflow in each watershed increases at different rates, with a statistically significant trend (at the 5 % level) of 9.87 and 7.72 mm year-1, respectively, in Meigang and Gaosha watersheds. Given the existence of interactions between precipitation and PE, the original climate elasticity of streamflow can not reflect the relationship of streamflow with precipitation and PE effectively. We modify this method and find the modified climate elasticity to be more accurate and reasonable using the correlation analysis. The analyses from the modified climate elasticity in the four watersheds show that a 10 % increase (decrease) in precipitation will increase (decrease) the annual streamflow by 14.1-16.3 %, while a 10 % increase (decrease) in PE will decrease (increase) the annual streamflow by -10.2 to -2.1 %. In addition, the modified climate elasticity is applied to estimate the contribution of annual precipitation and PE to the increasing annual streamflow in each watershed over the past 40 years. Our result suggests that the percentage attribution of the increasing precipitation is more than 59 % and the decreasing in PE is less than 41 %, indicating that the increasing precipitation is the major driving factor for the annual streamflow increase for each watershed. © 2012 Springer-Verlag.

Yan J.,CAS Wuhan Botanical Garden | Zhu C.,CAS Institute of Botany | Liu W.,CAS Institute of Botany | Luo F.,CAS Institute of Botany | And 4 more authors.
GCB Bioenergy | Year: 2015

The development of second-generation energy crops on marginal land relies on the identification of plants with suitable physiological properties. In this study, we measured and compared leaf photosynthesis and water use efficiency of 22 populations from three Miscanthus species, M. lutarioriparius, M. sacchariflorus, and M. sinensis, planted in two experimental fields located in Qingyang of the Gansu Province (QG) and Jiangxia of the Hubei Province (JH) in China. QG is located in the Loess Plateau, one of the world's most seriously eroded regions particularly abundant in semiarid marginal land. At both locations, M. lutarioriparius produced the highest biomass and had the highest photosynthetic rates (A), with the growing-season average of A reaching nearly 20 μmol m-2 s-1. Native to JH, M. lutarioriparius maintained a relatively high photosynthetic rate into the late growing stage in QG, for example, 15 μmol m-2 s-1 at temperature as low as 11.6 °C in October. All three species had higher water use efficiency (WUE) in semiarid QG than in warmer and wetter JH. In the late growing stage of M. lutarioriparius, instantaneous WUE (A/E) of the species nearly tripled in QG comparing to JH. Being able to maintain remarkably high photosynthetic rates when transplanted to a colder and drier location, these M. lutarioriparius populations serve as suitable wild progenitors for energy crop domestication in the Loess Plateau and other areas with the similar climates. © 2014 John Wiley & Sons Ltd.

Zhou X.-Y.,Chinese Academy of Meteorological Sciences | Zhou X.-Y.,National Climate Center | Zhang C.-Y.,National Climate Center | Guo G.-F.,Wuhan Regional Climate Center
Chinese Journal of Applied Ecology | Year: 2010

Forest soil organic carbon is an important component of global carbon cycle, and the changes of its accumulation and decomposition directly affect terrestrial ecosystem carbon storage and global carbon balance. Climate change would affect the photosynthesis of forest vegetation and the decomposition and transformation of forest soil organic carbon, and further, affect the storage and dynamics of organic carbon in forest soils. Temperature, precipitation, atmospheric CO2 concentration, and other climatic factors all have important influences on the forest soil organic carbon storage. Understanding the effects of climate change on this storage is helpful to the scientific management of forest carbon sink, and to the feasible options for climate change mitigation. This paper summarized the research progress about the distribution of organic carbon storage in forest soils, and the effects of elevated temperature, precipitation change, and elevated atmospheric CO2 concentration on this storage, with the further research subjects discussed.

Yin X.,Changjiang Geotechnical Engineering Co. | Lv W.,Wuhan Regional Climate Center | Xie L.,Changjiang Geotechnical Engineering Co.
ICPTT 2013: Trenchless Technology - The Best Choice for Underground Pipeline Construction and Renewal, Proceedings of the International Conference on Pipelines and Trenchless Technology | Year: 2013

A natural gas pipeline in Yangtze River Tunnel was constructed via shield method. When shield machine entered reception shaft, groundwater inflow and sand inflow occurred in the tunnel, which was 10.2 m away from the inner wall of reception shaft and led to segment displacement and ground collapse. Drilling was adopted to probe the shield segment displacement and the drill hole deflection was controlled by means of vertical shaft calibration of drill rigs using perpendicular line, which strictly controlled the accuracy of the probe to determine the displacement of tunnel segments. Segment damage and disturbance was effectively prevented by drilling speed control and blank bit replacement. This detection method with reasonable technology meets the exploration accuracy and attains reliable exploration data so that it can provide a reference for similar engineering problems. © ASCE 2013.

Wu J.,National Climate Center | Gao X.,National Climate Center | Giorgi F.,Abdus Salam International Center For Theoretical Physics | Chen Z.,Wuhan Regional Climate Center | Yu D.,Yichang Meteorological Bureau
Quaternary International | Year: 2012

High resolution multi-annual regional climate model (RegCM3) experiments were performed to simulate the effects of the Three Gorges Reservoir (TGR) on the climate of the surrounding areas. The model was run in double nested mode. Firstly a 50 km resolution simulation was conducted over the China domain driven by the coarse resolution NCEP/NCAR re-analysis. Then the output of the simulation was used to drive the model over the Three Gorges Area (TGA) at a resolution of 10 km. SUB-BATS scheme was employed in the 10 km simulation to represent the land surface at 2 km. Two 10 km simulation, one with and the other without the inland water in TGR were conducted. Comparison of the simulations against observation were firstly carried out to validation the model performances over TGA. The 10 km sensitivity experiments with and without the TGR showed that little or negligible effects can be found except directly over the TGR. Most of the simulated effects are noisy and not statistically significant, except for cooling over the TGR water body in both June-July-August (JJA) and December-January-February (DJF). The cooling leads to an/a insignificant decrease/slight decrease of precipitation over the TGR and nearby grid points, respectively. The cooling is larger in JJA compared to DJF. As a typical river-like reservoir, the width and coverage of the TGR does not have significant influence on the local climate over the area. © 2012 Elsevier Ltd and INQUA.

Discover hidden collaborations