SNPP-VIIRS夜间灯光影像去噪方法研究

高精度的夜间灯光数据能够有效反映人类空间活动特征,传统的SNPP-VⅡRS夜间灯光影像去噪方法容易忽略新增加或消失的有效灯光,且未处理灯光异常值,随着时间推移,去噪误差会逐渐增大。因此,本文提出了利用中值滤波与低阈值去噪相结合的方法过滤SNPP-VⅡRS夜间灯光影像中的异常值及背景噪声,并将去噪后的夜间灯光总量与GDP进行相关性分析及精度验证。试验结果表明,通过中值滤波与低阈值去噪结合的方法提取的夜间灯光总量与GDP的相关性优于传统方法,利用该方法建立的模型估算出的亮度值精度更高,证明该方法具有更高的去噪精度。     

基于作物空间分配模型的东北三省春玉米时空分布特征

利用1980-2010 年东北三省分县玉米播种面积与产量统计、耕地分布、农业灌溉分布以及作物适宜性分布等多源数据,结合基于交叉信息熵原理的作物空间分配模型（Spatial Production Allocation Model,SPAM）,在5'×5'的像元尺度模拟了春玉米种植面积与产量的时空分布,并重点分析了两者在纬向、经向,以及高程上的时空变化规律。结果显示：（1）玉米种植面积在2000 年前向北扩展至北纬44°~48°间,2000 年后在中南部出现大规模发展（北纬42°~44°）,并进一步向东扩展至东经123°~127°间,同时还表现为向低海拔（高程100 m以下）和较高海拔（高程200~350 m）扩展的态势;（2）单产在纬向上的增加区主要集中在北纬42°~48°,经向上的单产增加则相对均匀,高程上单产提升区主要集中在海拔350 m以下。（3）像元内玉米种植比例整体上由中低种植比例为主逐步演变为中高比例占据主体,并且中高种植比例像元对应的玉米单产水平整体上较高,反映了市场经济驱动下的玉米种植集聚化和规模化的发展趋势。     

1949–2014年中国三种主要作物的地理重心时空迁移分析（英文）

Spatial distribution changes in major crops can reveal important information about cropping systems.Here,a new centroid method that applies physics and mathematics to spatial pattern analysis in agriculture is proposed to quantitatively describe the historical centroids of rice,maize and wheat in China from 1949 to 2014.The geographical centroids of the rice area moved 413.39 km in a 34.32° northeasterly(latitude 3.08°N,longitude 2.10°E) direction at a speed of 6.36 km/year from central Hunan province to Hubei province,while the geographical centroids of rice production moved 509.26 km in the direction of 45.44° northeasterly(latitude 3.22°N,longitude 3.27°E) at a speed of 7.83 km/year from central Hunan province to Henan province.The geographical centroids of the maize area and production moved 307.15 km in the direction of 34.33° northeasterly(latitude 2.29°N,longitude 1.56°E) and 308.16 km in the direction of 30.79° northeasterly(latitude 2.39°N,longitude 1.42°E),respectively.However,the geographical centroids of the wheat area and production were randomly distributed along the border of Shanxi and Henan provinces.We divided the wheat into spring wheat and winter wheat and found that the geographical centroids of the spring wheat area and production were distributed within Inner Mongolia,while the geographical centroids of winter wheat were distributed in Shanxi and Henan provinces.We found that the hotspots of crop cultivation area and production do not always change concordantly at a larger,regional scale,suggesting that the changing amplitude and rate of each crops' yield differ between different regions in China.Thus,relevant adaptation measures should be taken at a regional level to prevent production damage in those with increasing area but decreasing production.     

极地产甲烷菌研究进展

产甲烷菌是一类重要的环境微生物,其代谢产生的甲烷(CH_4)是最重要的温室气体之一。现有研究表明,产甲烷菌广泛存在于极地湿地、沼泽、湖泊、苔原、冻土和冰川等各类生境之中,并在碳循环中发挥着重要作用。本文对极地产甲烷菌的群落结构、生物多样性、空间分布、环境影响因子(温度﹑营养物和pH)以及研究技术的最新进展进行了总结,并对极地产甲烷菌研究的未来发展进行了展望。     

东北三省耕地物候期对热量资源变化的响应

选取1998-2010 年期间的SPOT/VGT NDVI逐旬时间序列数据、物候观测数据和气候数据,利用函数拟合方法、GIS空间分析和统计方法,分析了东北三省不同耕地物候期对热量资源变化的响应关系。首先,基于拟合数据提取了耕地物候期特征(包括生长季开始期、峰值期、结束期与生长季长度等),验证结果显示与不同作物的观测物候期存在明显对应关系,能较好地反映作物物候期特征的宏观时空分异。其次,分析了1991-2009 年期间区内主要农业热量资源(≥ 10 oC初日,初霜日,温度生长期天数和≥ 10 oC积温) 的时空变化特征。最后,重点分析了1998-2009年期间耕地物候期特征对热量资源变化的响应。结果表明,生长季开始期与≥10 oC初日在松嫩平原北部、三江平原东部和吉林省中东部的正相关系显著(P < 0.01);生长季长度与温度生长期天数亦在上述区域内表现为显著正相关关系(P < 0.05);然而,生长季结束期与初霜日的相关关系整体上较不明显;此外,生长季长度与≥ 10 oC积温的相关关系存在两种相反的情形,在松嫩平原西北部、三江平原、吉林省中部和辽宁省中部的负相关关系显著(P < 0.05),而黑龙江省中南部和三江平原部分区域,两者相关系数达到0.55 (P < 0.05),分别反映了作物生长发育周期的缩短态势和中早熟作物被中晚熟作物替代的趋势。     

1980–2011年中国农作物种植结构时空变化（英文）

Understanding the spatial and temporal variations of cropping systems is very important for agricultural policymaking and food security assessment,and can provide a basis for national policies regarding cropping systems adjustment and agricultural adaptation to climate change.With rapid development of society and the economy,China's cropping structure has profoundly changed since the reform and opening up in 1978,but there has been no systematic investigation of the pattern,process and characteristics of these changes.In view of this,a crop area database for China was acquired and compiled at the county level for the period 1980–2011,and linear regression and spatial analysis were employed to investigate the cropping structure type and cropping proportion changes at the national level.This research had three main findings:(1) China's cropping structure has undergone significant changes since 2002;the richness of cropping structure types has increased significantly and a diversified-type structure has gradually replaced the single types.The single-crop types—dominated by rice,wheat or maize—declined,affected by the combination of these three major food crops in mixed plantings and conversion of some of their planting area to other crops.(2) In the top 10 types,82.7% of the county-level cropping structure was rice,wheat,maize and their combinations in 1980;however,this proportion decreased to 50.7% in 2011,indicating an adjustment period of China's cropping structure.Spatial analysis showed that 63.8% of China's counties adjusted their cropping structure,with the general change toward reducing the main food types and increasing fruits and vegetables during 1980–2011.(3) At the national level,the grain-planting pattern dominated by rice shifted to coexistence of rice,wheat and maize during this period.There were significant decreasing trends for 47% of rice,61% of wheat and 29.6% of maize cropping counties.The pattern of maize cropping had the most significant change,with the maize proportion decreasing in the zone from northeastern to southwestern China during this period.Cities and their surroundings were hotspots for cropping structural adjustment.Urbanization has significantly changed cropping structure,with most of these regions showing rapid increases in the proportion of fruit and vegetables.Our research suggests that the policy of cropping structural adjustment needs to consider geographical characteristics and spatial planning of cropping systems.In this way,the future direction of cropping structural adjustment will be appropriate and scientifically based,such as where there is a need to maintain or increase rice and wheat cropping,increase soybean and decrease maize,and increase the supply of fruit and vegetables.     

应用流体包裹体研究致密砂岩储层多期油气充注历史——以鄂尔多斯盆地镇泾地区延长组长8段砂岩为例

本文以鄂尔多斯盆地西南缘镇泾地区延长组长8段致密砂岩储层为例,利用流体包裹体岩相学、微束荧光光谱及显微测温等分析方法, 厘定油气充注期次和时间,同时结合储层成岩演化,探讨储层致密化与油气成藏过程。研究表明,储层孔隙沥青呈黄色和蓝白色荧光, 并以蓝白色为主;石油包裹体呈黄色、黄绿色及蓝白色荧光,并以后两者居多。与黄色荧光石油包裹体同期的盐水包裹体均一温度主峰为 80℃～90℃; 而与黄绿色和蓝白色荧光石油包裹体同期的盐水包裹体均一温度主峰分别为105℃～115℃和110℃～120℃。研究区储层主要经历了3期烃类充注：第一期发生在早白垩世早期（138～130Ma）,表现为少量的低熟油充注;第二期发生在早白垩世晚期（124～105Ma）,为关键成藏期,与大规模成熟油充注相关; 第三期发生在晚白垩世（85～73Ma）,古油藏发生调整,再次成藏。储层早成岩阶段以机械压实、薄膜状绿泥石、高岭石及微晶方解石胶结为主,在中高孔渗条件下发生了早期石油充注;随着继续压实,石英加大、孔隙填充绿泥石、高岭石及亮晶方解石胶结发育,储层逐渐致密化 晚期石油在低渗致密储层内的运聚成藏主要受早期烃类充注路径控制。     

近40年京津冀蒸发皿蒸发量变化特征及影响因子

为了研究京津冀地区蒸发皿蒸发量的变化特征及成因,在京津冀地区200多个气象站中选择资料序列完整且具有较长时间序列、测站环境评分都在70分以上(按照中国气象局对测站探测环境评分标准评分)、均匀分布的87个气象站,利用1970—2013年京津冀地区87个气象站蒸发皿蒸发量以及其他气象要素的观测资料,采用线性倾向估计法和完全相关系数法,分析近44年来京津冀蒸发量变化特征及影响因子。结果表明,近44年来,京津冀地区年、季蒸发量呈明显下降趋势。全年蒸发量减少速率由大到小分别为:山前平原区太行山区冀东平原区燕山丘陵区冀北高原区(蒸发速率由北向南逐渐增大);四季中下降速率为:春季秋季冬季夏季。分析蒸发量与影响因子的完全相关系数发现,气温日较差、日照时数和平均风速是影响京津冀地区蒸发皿蒸发量变化的主要因子,在平原地区,平均风速是主导因子;在山区和高原地区,日照时数是主导因子。     

典型滨海平原城市地下空间地质适宜性评价

地下空间地质适宜性评价是城市地下空间资源开发利用的重要前提。滨海平原城市因其特定的城市类型,需建立特定的地质适宜性评价体系来指导地下空间地质适宜性评价。本文以我国典型滨海平原城市日照市为研究区,深入分析了影响地下空间开发的地质环境因素,提出了基于基础性地质和约束性地质条件的滨海平原城市地质适宜性评价指标体系,进一步采用经验分值法、熵权法和综合评价模型厘定了研究区浅层（0～15 m）和次浅层（15～30 m）地下空间地质适宜性分区。结果显示,评价指标中水位埋深、断裂带、地面沉降和海水入侵等对地下空间地质适宜性的影响较大。研究区浅层和次浅层地下空间地质适宜性以适宜和较适宜为主,约占研究区面积的90%,不适宜区域约占研究区面积的10%。     

红层泥质砂岩隧道进口段注浆加固及效果评价

以江西某红层软岩隧道为背景对注浆加固进行分析。该隧道进口段的围岩揭示为破碎程度高、完整性差、地下水发育。在考虑工程实际的基础上,确定以小导管预注浆和全断面径向注浆为主的注浆加固方案。依据理论和经验公式确定相关的注浆参数。通过现场监测对注浆效果进行了详细评价。监测结果表明:注浆在衬砌外部形成了较为稳定的注浆圈,降低了围岩的遇水软化程度,提高了围岩强度,减小了围岩的渗透系数,拱顶沉降及围岩收敛最终趋于稳定。隧道右边墙围岩破碎程度高,同时拱顶围岩注浆效果欠佳,建议施工中加强对右边墙和拱顶的支护。