Northeast China is an important agricultural region in China. The NortheastPlain is the largest plain in the country and one of the three famous black soil zones in the world.Despite of fertility of the soil, however,...Northeast China is an important agricultural region in China. The NortheastPlain is the largest plain in the country and one of the three famous black soil zones in the world.Despite of fertility of the soil, however, large-scale agricultural development mainly took placesince 1900. The land exploitation and utilization has been fast and intensive in this region sincethen and change in the land-cover process has been remarkable. Both national and internationalresearchers on land use and land cover are paying more attention to these processes in this regionand their implication for local ecological environment. This article discusses the land reclamationprocesses and their main driving forces in Northeast China since 1900. According to the research,the 20th century was the most important period for land reclamation in Northeast China. In theseyears the rate, intensity and quantity of land reclamation have been staggering, and more than 100000km^2 of land was converted into farmland. This magnitude of land reclamation inland is unique inthe world. Research on the land reclamation of Northeast China can provide some data on the effectof human activity on environment. As in many other places in the world, the primary driving force ofreclamation in Northeast China was the increasing pressure of population. In the 20th century thepopulation increased from 10 x 10~6 to 110 x 10~6 in Northeast China and from 400 x 10~6 to 1. 3 x10^9 in China. Population pressure is thus the most important driving force for land reclamation.展开更多
High-precision(±0.1 ppm) and high-frequency(hourly averaged) in situ measurements of atmospheric carbon dioxide(CO2) were made for the first time from August 2005 to July 2007 at Yanbian,China using a non-dispers...High-precision(±0.1 ppm) and high-frequency(hourly averaged) in situ measurements of atmospheric carbon dioxide(CO2) were made for the first time from August 2005 to July 2007 at Yanbian,China using a non-dispersive Infrared(NDIR) analyzer with National Oceanic and Atmospheric Administration/Earth System Research Laboratory(NOAA/ESRL) standards.The results of these measurements are presented in this paper and are used to investigate the regional representativeness of regional background data at Yanbian and determine the CO2 emission source regions in Northeast Asia.The phase of the monthly variations at Yanbian reflects the special regional characteristics,which were overall in excellent agreement with other observatories in the middle-to-high latitudes in the Northern Hemisphere.Applying a hybrid receptor model to the regional emission source events in cold period(November-April),we estimated the distribution of the major CO2 emissions in the northeast Asia.The results indicated that the strongest potential emission areas contributing to Yanbian are the Beijing & Tianjin metropolitan areas,southwestern part of Shandong Province including Jinan,and Vladivostok.The results of this study reveal the usefulness of in situ CO2 measurements at Yanbian in establishing the scientific foundation for monitoring the large CO2 emission areas in northern China and Russia.Continued monitoring of CO2 at Yanbian within a regional network should provide significant contributions to both understanding the global/regional carbon cycle and constraining "top-down" emissions in Northeast Asia.展开更多
文摘Northeast China is an important agricultural region in China. The NortheastPlain is the largest plain in the country and one of the three famous black soil zones in the world.Despite of fertility of the soil, however, large-scale agricultural development mainly took placesince 1900. The land exploitation and utilization has been fast and intensive in this region sincethen and change in the land-cover process has been remarkable. Both national and internationalresearchers on land use and land cover are paying more attention to these processes in this regionand their implication for local ecological environment. This article discusses the land reclamationprocesses and their main driving forces in Northeast China since 1900. According to the research,the 20th century was the most important period for land reclamation in Northeast China. In theseyears the rate, intensity and quantity of land reclamation have been staggering, and more than 100000km^2 of land was converted into farmland. This magnitude of land reclamation inland is unique inthe world. Research on the land reclamation of Northeast China can provide some data on the effectof human activity on environment. As in many other places in the world, the primary driving force ofreclamation in Northeast China was the increasing pressure of population. In the 20th century thepopulation increased from 10 x 10~6 to 110 x 10~6 in Northeast China and from 400 x 10~6 to 1. 3 x10^9 in China. Population pressure is thus the most important driving force for land reclamation.
基金supported by National Research Foundation of Korea (NRF) funded by the Korea government (MEST) (Grant No.2010-0029119)
文摘High-precision(±0.1 ppm) and high-frequency(hourly averaged) in situ measurements of atmospheric carbon dioxide(CO2) were made for the first time from August 2005 to July 2007 at Yanbian,China using a non-dispersive Infrared(NDIR) analyzer with National Oceanic and Atmospheric Administration/Earth System Research Laboratory(NOAA/ESRL) standards.The results of these measurements are presented in this paper and are used to investigate the regional representativeness of regional background data at Yanbian and determine the CO2 emission source regions in Northeast Asia.The phase of the monthly variations at Yanbian reflects the special regional characteristics,which were overall in excellent agreement with other observatories in the middle-to-high latitudes in the Northern Hemisphere.Applying a hybrid receptor model to the regional emission source events in cold period(November-April),we estimated the distribution of the major CO2 emissions in the northeast Asia.The results indicated that the strongest potential emission areas contributing to Yanbian are the Beijing & Tianjin metropolitan areas,southwestern part of Shandong Province including Jinan,and Vladivostok.The results of this study reveal the usefulness of in situ CO2 measurements at Yanbian in establishing the scientific foundation for monitoring the large CO2 emission areas in northern China and Russia.Continued monitoring of CO2 at Yanbian within a regional network should provide significant contributions to both understanding the global/regional carbon cycle and constraining "top-down" emissions in Northeast Asia.
