The grain production potential assessment with multiple cropping index (MCI) in China

This paper retrieved the information of cropland and MCI (Multiple Cropping Index) of China in 2000 and 2009 with SPOT NDVI time series data and utilized meteorological data and statistical data released by the state to calculate potential MCI and statistical MCI. Then, the MCI potential of China and grain production potential based on MCI were calculated in order to analyze the potential spatial distribution characteristics of MCI and the potential spatial pattern characteristics. The national mean MCI potentials in 2000 and 2009 are 0.485 and 0.506 respectively calculated with the remote sensing method and statistical method. And the grain productivity potentials of China based on MCI are 51% and 53% respectively. The improvement of MCI potential not only increases hydrothermal utilization rate and the utilization rate of cropland but also enormously enhances the food security degree of China and provides more available cropland area for the economic development

The synthesis and characterization of 1111-type diluted magnetic semiconductors (La1-xSrx)(Zn1-xTMx)AsO (TM = Mn, Fe, Co)

The doping effect of Sr and transition metals Mn, Fe, Co into the direct-gap semiconductor LaZnAsO has been investigated. Our results indicate that the single phase ZrCuSiAs-type tetragonal crystal structure is preserved in (La1-xSrx)(Zn1-xTMx)AsO (TM = Mn, Fe, Co) with the doping level up to x = 0.1. While the system remains semiconducting, doping with Sr and Mn results in ferromagnetic order with TC ~ 30K, and doping with Sr and Fe results in a spin glass like state below ~6K with a saturation moment of ~0.02 muB/Fe, an order of magnitude smaller than the ~0.4 muB/Mn of Sr and Mn doped samples. The same type of magnetic state is observed neither for (Zn,Fe) substitution without carrier doping, nor for Sr and Co doped specimens.Comment: Accepted for publication in EP

Dynamics of wetlands and their effects on carbon emissions in China coastal region - Case study in Bohai Economic Rim

Wetlands are one of the largest carbon sinks in the world due to their large carbon storage, potential for carbon sequestration in peat formation, sediment deposition and plant biomass. However, rapid economic development is causing changes to wetland carbon storage. China has participated in the implementation of the Kyoto Protocol and is decreasing its carbon emissions. Analyzing the carbon changes that are caused by wetland dynamics may provide some insights regarding decreasing carbon emissions. Therefore, wetland data from 1985, 1995 and 2005 were extracted from remote sensing images. Using spatial analysis and statistics, we determined that the water body area continued to increase, whereas the swamp, floodplain and shallow areas tended to decrease during the period from 1985 to 2005. Those changes caused wetland carbon stock to decrease. The conversion of other land use categories to wetland was the primary cause of carbon stock loss. Therefore, it is more beneficial for China to decrease per capita carbon emissions by decreasing carbon emissions from the conversion of other land use categories to wetlands. (C) 2013 Elsevier Ltd. All rights reserved.Wetlands are one of the largest carbon sinks in the world due to their large carbon storage, potential for carbon sequestration in peat formation, sediment deposition and plant biomass. However, rapid economic development is causing changes to wetland carbon storage. China has participated in the implementation of the Kyoto Protocol and is decreasing its carbon emissions. Analyzing the carbon changes that are caused by wetland dynamics may provide some insights regarding decreasing carbon emissions. Therefore, wetland data from 1985, 1995 and 2005 were extracted from remote sensing images. Using spatial analysis and statistics, we determined that the water body area continued to increase, whereas the swamp, floodplain and shallow areas tended to decrease during the period from 1985 to 2005. Those changes caused wetland carbon stock to decrease. The conversion of other land use categories to wetland was the primary cause of carbon stock loss. Therefore, it is more beneficial for China to decrease per capita carbon emissions by decreasing carbon emissions from the conversion of other land use categories to wetlands. (C) 2013 Elsevier Ltd. All rights reserved

Analysis of relationships between land surface temperature and land use changes in the Yellow River Delta

This study analyzed land use and land cover changes and their impact on land surface temperature using Landsat 5 Thematic Mapper and Landsat 8 Operational Land Imager and Thermal Infrared Sensor imagery of the Yellow River Delta. Six Landsat images comprising two time series were used to calculate the land surface temperature and correlated vegetation indices. The Yellow River Delta area has expanded substantially because of the deposited sediment carried from upstream reaches of the river. Between 1986 and 2015, approximately 35% of the land use area of the Yellow River Delta has been transformed into salterns and aquaculture ponds. Overall, land use conversion has occurred primarily from poorly utilized land into highly utilized land. To analyze the variation of land surface temperature, a mono-window algorithm was applied to retrieve the regional land surface temperature. The results showed bilinear correlation between land surface temperature and the vegetation indices (i.e., Normalized Difference Vegetation Index, Adjusted-Normalized Vegetation Index, Soil-Adjusted Vegetation Index, and Modified Soil-Adjusted Vegetation Index). Generally, values of the vegetation indices greater than the inflection point mean the land surface temperature and the vegetation indices are correlated negatively, and vice versa. Land surface temperature in coastal areas is affected considerably by local seawater temperature and weather conditions

Influences of the Grain-for-Green project on grain security in southern China

Ensuring grain security has always been a top priority in China. As one of the major grain production areas in China, southern China is currently being criticized for the urban encroachment on prime agricultural land and decrease in grain production due to Grain-for-Green project. Based on the erosion pattern from the RUSLE model, spatial analysis is performed to analyze the possible loss of grain production if cropland under different degrees of soil erosion is exposed to the Grain-for-Green project. The projected total grain production on the basis of the 2000 grain production data in south China will decrease by 7.77% if cultivation is stopped on the cropland with high, very high, severe and very severe erosion, which, although not affects the grain security in southern China, would damage the grain security for the whole China. However, if all cropland on slopes above 25 is converted to forest or grassland, grain production will decrease by 2.1%. If all cropland covered with high, very high, severe and very severe erosion on slopes above 25 is converted to forest or grassland, grain production will decrease by 0.91%. Neither of the two measures will damage grain security in southern China, nor the whole China. So, the government should continue the Grain-for-Green project based on both slope and soil erosion degrees to ensure the grain security and reduce soil erosion at the same time. Published by Elsevier Ltd.Ensuring grain security has always been a top priority in China. As one of the major grain production areas in China, southern China is currently being criticized for the urban encroachment on prime agricultural land and decrease in grain production due to Grain-for-Green project. Based on the erosion pattern from the RUSLE model, spatial analysis is performed to analyze the possible loss of grain production if cropland under different degrees of soil erosion is exposed to the Grain-for-Green project. The projected total grain production on the basis of the 2000 grain production data in south China will decrease by 7.77% if cultivation is stopped on the cropland with high, very high, severe and very severe erosion, which, although not affects the grain security in southern China, would damage the grain security for the whole China. However, if all cropland on slopes above 25 is converted to forest or grassland, grain production will decrease by 2.1%. If all cropland covered with high, very high, severe and very severe erosion on slopes above 25 is converted to forest or grassland, grain production will decrease by 0.91%. Neither of the two measures will damage grain security in southern China, nor the whole China. So, the government should continue the Grain-for-Green project based on both slope and soil erosion degrees to ensure the grain security and reduce soil erosion at the same time. Published by Elsevier Ltd

Artificial neural network model for ozone concentration estimation and Monte Carlo analysis

Air pollution in urban atmosphere directly affects public-health; therefore, it is very essential to predict air pollutant concentrations. Air quality is a complex function of emissions, meteorology and topography, and artificial neural networks (ANNs) provide a sound framework for relating these variables. In this study, we investigated the feasibility of using ANN model with meteorological parameters as input variables to predict ozone concentration in the urban area of Jinan, a metropolis in Northern China. We firstly found that the architecture of network of neurons had little effect on the predicting capability of ANN model. A parsimonious ANN model with 6 routinely monitored meteorological parameters and one temporal covariate (the category of day, i.e. working day, legal holiday and regular weekend) as input variables was identified, where the 7 input variables were selected following the forward selection procedure. Compared with the benchmarking ANN model with 9 meteorological and photochemical parameters as input variables, the predicting capability of the parsimonious ANN model was acceptable. Its predicting capability was also verified in term of warming success ratio during the pollution episodes. Finally, uncertainty and sensitivity analysis were also performed based on Monte Carlo simulations (MCS). It was concluded that the ANN could properly predict the ambient ozone level. Maximum temperature, atmospheric pressure, sunshine duration and maximum wind speed were identified as the predominate input variables significantly influencing the prediction of ambient ozone concentrations

An Adaptive Piecewise Harmonic Analysis Method for Reconstructing Multi-Year Sea Surface Chlorophyll-A Time Series

High-quality remotely sensed satellite data series are important for many ecological and environmental applications. Unfortunately, irregular spatiotemporal samples, frequent image gaps and inevitable observational biases can greatly hinder their application. As one of the most effective gap filling and noise reduction approaches, the harmonic analysis of time series (HANTS) method has been widely used to reconstruct geographical variables; however, when applied on multi-year time series over large spatial areas, the optimal harmonic formulas are generally varied in different locations or change across different years. The question of how to choose the optimal harmonic formula is still unanswered due to the deficiency of appropriate criteria. In this study, an adaptive piecewise harmonic analysis method (AP-HA) is proposed to reconstruct multi-year seasonal data series. The method introduces a cross-validation scheme to adaptively determine the optimal harmonic model and employs an iterative piecewise scheme to better track the local traits. Whenapplied to the satellite-derived sea surface chlorophyll-a time series over the Bohai and Yellow Seas of China, the AP-HA obtains reliable reconstruction results and outperforms the conventional HANTS methods, achieving improved accuracy. Due to its generic approach to filling missing observations and tracking detailed traits, the AP-HA method has a wide range of applications for other seasonal geographical variables

Application of Surface Spline Interpolation Method in Parameter Estimation of a PM2.5 Transport Adjoint Model

A new method for the estimation of initial conditions (ICs) in a PM2.5 transport adjoint model is proposed in this paper. In this method, we construct the field of ICs by interpolating values at independent points using the surface spline interpolation. Compared to the traditionally used linear interpolation, the surface spline interpolation has an advantage for reconstructing continuous smooth surfaces. The method is verified in twin experiments, and the results indicate that this method can produce better inverted ICs and less simulation errors. In practical experiments, simulation results show good agreement with the ground-level observations during the 22nd Asia-Pacific Economic Cooperation summit period, demonstrating that the new method is effective in practical application fields

Spatial-temporal variability of coastline in bohai rim based on fractal dimension

This paper extracted the spatial distribution of the continental coastline of Bohai Rim utilizing Remote Sensing and GIS spatial analysis techniques, and calculated the fractal dimension of the coastline by boxcounting method, with a time from 1990 to 2010. Moreover, we analyzed the characteristics of spatialtemporal variability of the coastline's length and fractal dimension, the relationship between the large scales length change and fractal dimension change. During the research period, the coastline length of the study area increased progressively and the most significant change in coastline length was found in Tianjin Municipality. Especially after 2000, the coastline length entered a period of rapid growth. In addition, the fractal dimension of the overall coastline of the study area was between the fractal dimensions of the regional coastlines and was close to the maximum fractal dimensions of these regional coastlines. The fractal dimension of the coastline in Bohai Rim was increasing during the research period, large scale project such as ports construction, reduced tortuous degree of the coastline