东北地区经济差异演变与空间格局

以人均国内生产总值为测度区域经济差异的变量指标,运用标准差、标准差系数、相对发展率、泰尔指数定量分析1995年以来东北地区区域经济差异变化特征与区域经济空间格局.分析表明:东北地区经济发展绝对差异总体增大,相对差异呈明显的倒“U”型,但金融危机过后有进一步上升趋势;区域内部差异远大于各省区之间差异,各省区内部差异明显不同,黑、辽与吉、蒙东呈现出经济发展水平与区域差异水平匹配的“高高”、“低低”俱乐部发展趋势;经济水平呈现出显著的“T”字型空间格局,区域经济发展速度南北差异明显,辽中南城市群是东北地区经济发展的核心地.东北振兴战略实施对东北地区经济差异演变与空间格局的形成起到重要作用,主体功能区划将进一步促进东北地区经济的协调发展.     

Change analysis of rice area and production in China during the past three decades

Rice＇s spatial-temporal distributions, which are critical for agricultural, environ- mental and food security research, are affected by natural conditions as well as socio-eco- nomic developments. Based on multi-source data, an effective model named the Spatial Production Allocation Model （SPAM） which integrates arable land distribution, administrative unit statistics of crop data, agricultural irrigation data and crop suitability data, was used to get a series of spatial distributions of rice area and production with 10-km pixels at a national scale -it was applied from the early 1980s onwards and used to analyze the pattern of spatial and temporal changes. The results show that significant changes occurred in rice in China during 1980-2010. Overall, more than 50% of the rice area decreased, while nearly 70% of rice production increased in the change region during 1980-2010. Spatially, most of the increased area and production were in Northeast China, especially, in Jilin and Heilongjiang; most of the decreased area and production were located in Southeast China, especially, in regions of rapidly urbanization in Guangdong, Fujian and Zhejiang. Thus, the centroid of rice area was moved northeast approximately 230 km since 1980, and rice production about 320 km, which means rice production moved northeastward faster than rice area because of the significant rice yield increase in Northeast China. The results also show that rice area change had a decisive impact on rice production change. About 54.5% of the increase in rice pro- duction is due to the expansion of sown area, while around 83.2% of the decrease in rice production is due to contraction of rice area. This implies that rice production increase may be due to area expansion and other non-area factors, but reduced rice production could largely be attributed to rice area decrease.     

东北地区积雪变化及对气候变化的响应

利用东北地区1961-2017年162个气象站点逐日气象观测数据,分析了积雪的变化及其与气候变化的关系。结果表明:(1)平均年积雪日数和累积积雪深度为75.3 d和582.1 cm,呈高纬多低纬少、山地多平原少的分布,大兴安岭北部、小兴安岭和长白山区积雪日数达140 d以上,积雪日数多的地方累积积雪深度也较深。(2)平均积雪初终日和积雪期分别为11月7日、4月1日和145 d,积雪初日自大兴安岭北部向辽宁沿海地区推进;积雪初日早的地区积雪结束的也晚,积雪期更长,黑龙江大部分地区均超过了150 d。(3)积雪日数和累积积雪深度最大值均出现在1月,以1月下旬最多;积雪初日和终日最多分别出现在11月和3月,以11月上旬和3月下旬最多。(4)年积雪日数和累积积雪深度分别以1.88 d·(10a)~(-1)和71.94 cm·(10a)~(-1)的速率增加,在21世纪10年代达到年代最高值,秋季、冬季和春季积雪日数和累积积雪深度均呈增加趋势,冬季增加最为显著。积雪初日显著推迟、积雪终日提前、积雪期缩短,变化速率分别为1.44 d·(10a)~(-1)、-2.27 d·(10a)~(-1)和-3.72 d·(10a)~(-1);162个气象站点中,积雪日数和累积积雪深度均有75%以上的站点呈增加趋势,积雪初日推迟、积雪终日提前和积雪期缩短的站点分别为86.4%、98.1%和96.3%。(5)冬半年积雪受降水量(有效降雪量)的影响要大于平均气温的影响;积雪初日与11月平均气温和10月降水量相关性较好,积雪终日与2月温度因子相关性较好;随着纬度的升高和海拔的抬升,积雪日数和累积积雪深度增加,积雪初日提前、积雪终日推后、积雪期延长。     

黔东北地区钒矿石与围岩稀土元素地球化学特征及其意义

通过对黔东北地区沉积型钒矿的矿石和围岩样品进行稀土元素含量测试,分析表明本地区含矿岩系中稀土元素含量以LREE为主,并且是HREE的1.45～3.09倍。并对各样品中稀土元素含量、组成特征及Ce、Eu亏损程度研究,揭示了该区钒矿形成时的沉积环境比矿层顶、底部沉积时期更靠近陆源区,且钒矿层与矿层顶、底板沉积时因海平面升降导致古地理环境有较大差异。从REE与矿石主要化学组分等相关性分析发现REE与粘土、V2O5等呈正相关关系,与CaO、MgO、Fe2O3等呈负相关关系,与SiO2的相关性不明显。从REE与矿石化学成分之间的关系初步表明了钒矿的形成是受沉积环境、粘土吸附作用、沉积作用等因素复合的结果。通过与黔北遵义、湖南吉首-张家界一带的钒镍钼铂族元素成矿环境、成矿物质来源、稀土元素分布等特征进行对比,揭示了本区钒矿的独特之处,为该区首次从地球化学元素方面深入研究钒矿综合特征特提供了重要的、基础性的参考资料。     

湿地来了新“客人”

近日,商丘市睢阳区南湖湿地迎来了一群特殊的“客人”——东方白鹳。东方白鹳属于大型涉禽,是国家一级保护动物,主要在东北地区中北部繁殖,被列为濒危物种,全球仅存4000余只,有“鸟界国宝”“鸟类大熊猫”之称。     

日本地震冲击波

日本东北地区太平洋海域3月11日发生该国有地震观测记录以来最高震级地震．强震不仅显著改变日本地貌,而且对地壳位移、地球自转．全球气候等都产生一定的影响。     

Receiver function study of the crustal structure of Northeast China:Seismic evidence for a mantle upwelling beneath the eastern flank of the Songliao Basin and the Changbaishan region

Northeast China is a unique place to study intra-plate volcanism.We analyzed P-wave receiver function data recorded by 111 permanent broadband seismic stations in Northeast China.The results show that the crustal thickness varies from 27.9 km beneath the eastern flank of the Songliao Basin to 40.7 km beneath the Great Xing'an Range region.The large depth variations of the Moho can be largely but not completely explained by surface topography.The residual Moho depth calculated based on the Airy's isostasy mo...     

气候变化条件下东北地区多年冻土变化预测

东北多年冻土（除非指明是季节冻土,以下将多年冻土简称冻土）是中国第二大冻土分布区,主要发育＂兴安-贝加尔型＂冻土.由于处在欧亚大陆冻土区南缘,冻土的热稳定性差,寒区生态的敏感性强.在气候变暖条件下,冻土已经和正在发生着＂三向＂退化.为预测冻土南界和地温变化,根据47个气象站资料并在SHAW模型对植被影响地表温度修正的基础上,建立了冻土地表温度分布的等效纬度模型.结合非稳态热传导模型的有限元数值计算,以多模型结合的方法,进一步计算和分析了目前、50年和100年后冻土地温分区变化.结果表明,在目前地表温度为1.5℃范围,仍可残留冻土.以0.048℃a-1气温递增速率,在目前地表温度为0.5℃和-0.5℃的区域,50年和100年后各自仍有可能存在冻土;冻土面积将由现在的2.57×105 km2各自减至1.84×105和1.29×105 km2,分别减少28.4%和49.8%,且东部退化幅度大于西部.同时,区域地温升高,冻土厚度减薄;稳定型（年平均地温Tcp≤-1.0℃）冻土面积逐渐减小,将由现在的1.07×105 km2分别减少至8.8×104 km2（50年后）和5.6×104 km2（100年后）.相应地,不稳定型（Tcp〉-1.0℃）多年冻土和季节冻土的面积增加,冻土南界将显著北移.冻土环境的变化,将给东北寒区工程设施和生态环境带来重要影响.减少或避免人为地改变冻土赋存条件,是保护冻土环境较可行的途径.