贝加尔湖地区2003年-2005年间CO时空动态的遥感分析

主要基于搭载在Envisat卫星上的SCIAMACHY传感器反演的2003年-2005年间CO柱浓度数据产品,并结合生物质燃烧和土壤等辅助数据对贝加尔湖区域上空CO时空分布特征及其来源进行了分析,发现贝加尔湖区域2003年到2005年间的CO年均值浓度为2.28×10^18molecule.cm^-2,远高于欧亚大陆的本底浓度1.6×10^18molecule.cm^-2;CO浓度具有明显的季节波动,2003年的3月高达2.92×10^18molecule.cm^-2;CO的月均值变化和生物质燃烧具有很强的相关性,贝加尔湖地区4个大城市中赤塔（Chita）的年均值浓度是最高的;各土壤类型上空CO月均值季节变化显著,其中薄层栗钙土（Kh24-2b）类型土壤的振幅达2.91×10^18molecule.cm^-2。     

秸秆焚烧遥感监测进展分析与展望

秸秆焚烧是生物质燃烧的重要组成部分,不仅导致秸秆资源浪费,而且还会对环境造成严重危害。传统秸秆焚烧监测方法以人工巡查为主,监测范围受限且人力物力资源耗费大。遥感技术作为新兴的地表信息监测手段,给秸秆焚烧大范围监测带来了发展契机。介绍了遥感技术在秸秆焚烧火点监测、过火面积估算和焚烧迹地监测3个方面的基本原理、监测方法和研究进展,并分析了遥感技术在秸秆焚烧监测应用中存在的不足。在此基础上,从多源数据融合互补、监测方法优化集成、监测信息深入挖掘和时空信息决策服务等4个方面对秸秆焚烧遥感监测的未来发展进行了展望。     

基于MODIS数据的亚马逊热带雨林火灾时空变化规律研究

频繁发生的森林大火对亚马逊热带雨林造成了大面积破坏,获取不同年份的火灾影响范围以及植被破坏情况,有助于了解该地区火灾时空演变规律以及火灾与植被的相互作用关系,进而探究火灾发展机理,为防灾减灾提供科学依据。为此,利用2015～2019年MODIS植被指数产品与地表温度产品,构建MODIS全球扰动指数模型（MGDI）,结合火点数据（以下统称MOD14A1）、植被连续场数据（Vegetation Continuous Field,VCF）提取1 000 m分辨率下的燃烧范围和燃烧强度,并分析研究区域5年内的火灾分布时空规律。实验结果表明：(1)火灾主要分布在巴西中部以及巴西与玻利维亚的交界处,占燃烧区总面积的67%左右;(2)燃烧范围以及燃烧强度的综合信息显示火灾整体呈现出“升—降—升”的趋势;(3)火灾多发生于灌木草地（50%以上）以及阔叶林（30%）,且火灾多发在旱季;在全球变暖大背景下,火灾发生频率呈上升趋势;（4）人类活动范围扩张、不合理农业开垦、森林砍伐导致研究区内草地退化严重,农业用地以及建筑用地逐年上升,在一定程度上为火灾的发生、传导提供了良好的条件。     

融合探测和预测数据的平流层风场建模方法北大核心

平流层浮空器因驻空时间长、覆盖范围广和搭载能力强等显著优势,在对地观测、侦查预警、环境监测等领域有巨大的应用前景。由于平流层浮空器结构尺度大,飞行速度低,其飞行性能和驻空能力受环境风场影响显著,其典型驻空高度20千米高度附近的风场环境在长周期大尺度范围较为稳定,但短周期小尺度内风速风向存在一定变化,因此平流层风场的获取、建模和更新对于飞行航迹规划、飞行控制至关重要。以我国某区域多点气象站的实际数据和预测数据为依据,通过双线性差值和函数拟合的方法对两类风场数据进行融合,进行四维风场环境的重构建模,得到该区域风场的时空特性,为平流层浮空器轨迹规划和控制提供技术支持。     

撞击气流床气化炉内浓度场和温度场的数值模拟

运用PDF燃烧模型模拟以柴油为模拟气化介质的撞击气流床气化炉气化时的过程,结果与实验较吻合。还考察氧燃料比与合成气组成的关系,分析了气化炉中的温度和浓度分布情况。模拟结果表明:氧燃料比与合成气组成关系很大,随着氧燃料比例降低合成气中有效气(CO H2)浓度升高;通过温度变化预测撞击火焰上升的高度,得出模拟条件下撞击火焰上升的高度与气化炉内径之比在1.0左右;随着反应进行,气化炉轴向上O2浓度迅速下降,H2浓度逐渐升高,H2O浓度逐渐降低。     

植被功能型差异对地表反照率时空分布的影响分析

地表反照率是表征地球表面捕获太阳辐射能力的特征参量,是影响气候系统的关键因素。植被通过物理(反照率)和生物过程(蒸散)影响陆地区域的能量收支过程,进而调控区域气候特征,其中陆表植被的变化及其可能的反照率影响规律受到了研究者的重视。以北京地区为例,利用MODIS地表反照率产品,结合地表覆盖类型产品中的植被功能型数据,计算并分析了2008~2013年北京地区典型植被功能型差异对地表反照率时空分布的影响。结果表明:北京地区典型植被功能型共6种,按其平均地表反照率从大到小依次为:谷物作物、城市用地、灌丛、落叶阔叶林、常绿针叶林及水体。因不同植被功能型的分布及变化对地表反照率的时空分布有直接影响,北京地区平均地表反照率总体呈东高西低、南高北低趋势,秋季最小,冬季次之,春、夏较大,且2008~2013年地表反照率呈现变化量约为-0.79×10-3/a的缓慢减小趋势。     

基于被动微波与时空联合算法的云下像元LST重建

地表温度作为衡量地球表面水热平衡的关键参数,具有两大时空分布特征:第一,空间分布一致性,即属性相近的像元地表温度与其地表亮温间的相关关系相对稳定;第二,时间序列周期性,且同一地区时间越接近地表温度值越相似。基于这两大特征将空间统计模型与时间序列滤波相结合,提出了用于云下像元地表温度重建的时空联合算法。以2008年MODIS地表温度产品为研究对象,采用Landsat TM数据和AMSR_E地表亮温数据重建中国9个省份的地表温度值,并与基于MODIS地表分类产品的多通道统计模型重建结果进行对比。实验结果表明,所提算法实用性强,能有效实现大面积复杂下垫面区域的地表温度重建;平均重建误差约为1.2 K,相较于基于下垫面分类的多通道统计模型下降了76%,算法精度明显提高。
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包头市细颗粒物遥感监测混合线性模型

以PM_(2.5)为主的颗粒物污染是影响我国城市空气质量的首要因素之一。针对城市尺度,高时间分辨率的MODIS气溶胶产品空间分辨率不足,且气溶胶光学厚度(AOD)与PM_(2.5)回归精度受到季节因素的影响而精度不足的问题,以Landsat-8OLI为数据源,选取季节因子为影响AOD变化的随机效应,以风速、地表温度、AOD等为固定效应,提出AOD与实测PM_(2.5)关系的混合线性模型。结果表明,与线性模型相比,该模型有较好的回归精度;包头市PM_(2.5)浓度时空差别明显,PM_(2.5)浓度冬季浓度水平最高,春季最低;从空间分布来看昆都仑区污染较高,青山区北部次之,东河区和九原区最低。     

多源卫星融合的广东海域海面风场特征

针对大部分风场时空融合算法复杂、执行效率低、业务推广难的问题,基于HY-2A和MetOp-B海面风场数据提出一种快速可行的时间空间插值融合算法,并将融合产品用于广东附近海域海面风场特征的研究。算法通过时间匹配和空间插值,获取了空间分辨率为0.25°×0.25°、数据时间差控制在30分钟以内的融合风场。浮标观测数据验证结果表明,该方法有效地弥补2种卫星数据的覆盖盲区,融合风速和风向均具有较好的精度。在此基础上,本文利用融合风场成功捕捉1622号台风“海马”,掌握该台风当日对全广东附近海域海面风场的影响;分析2016年10月研究区域的上、下旬及整个月份的风场分布特征和变化规律,为海洋预报、区域海洋动力环境研究以及海洋防灾减灾策略的制定等提供数据支撑。     

校园供热节能控制系统研究与开发

介绍了针对校园冬季供暖的节能控制方法.根据校园供暖的特点和学校作息制度,采用分时分区供暖、室外温度和远端用户室内温度补偿进行优化,以达节能目的.在供暖控制系统中采用可编程序控制器(PLC),用于对现场数据采集和处理,并完成时现场供暖设备的自动控制,实现远端温度,室外温度,供暖时间补偿的节能优化方式.     

Variability and trends of mean maximum and mean minimum air temperature in Greece from ground-based observations and NCEP–NCAR reanalysis gridded data

In this study, the variability and trends of the mean annual and seasonal maximum and minimum surface air temperature in Greece are examined, using monthly data sets of 26 meteorological stations from the Hellenic National Meteorological Service (HNMS) and gridded data from the National Center for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) Reanalysis project for the period 1955–2001. NCEP–NCAR reanalysis data sets are created by assimilating climate observations from different sources, including ships, satellites, ground stations, radiosonde observations and radar. The general purpose of conducting reanalyses is to produce multi-year global state-of-the-art gridded representations of atmospheric states, generated by a constant model and a constant data-assimilation system.

The trends of the mean extreme air temperatures were evaluated, using the Mann–Kendall criterion, and, in the process, factor analysis was applied to both the stations' and the NCEP–NCAR grid points time series. Regarding the mean maximum air temperature, the first main factor, which explains a high percentage of the total variance, presents a statistically significant (CL?=?95%) negative trend only during the winter. The first main factor of the mean minimum air temperature manifests a statistically significant (CL?=?95%) positive trend during the summer and the year, and a statistically significant (CL?=?95%) negative trend in autumn and winter. These findings were compared to the respective ones of the NCEP–NCAR reanalysis data and significant differences in the spatial distribution and temporal variability of the extracted new factors were found. These differences between the two examined data sets could be attributed to topographical factors such orography and land–sea distribution, which could not be represented properly by the reanalysis model.     

Spatial and temporal variations of aerosol optical depth in China during the period from 2003 to 2006

Spatial and temporal variations of aerosol optical depth (AOD, or τ) in China were investigated using MODIS-derived aerosol data for a period of 2003–2006. The geographical distribution patterns of 4-year mean AOD for total, τ_0.55 (AOD at 0.55 μm), fine, τ_0.55-fine, and coarse, τ_0.55-coarse, aerosols over China were addressed. These results indicate that the distribution of aerosol was largely affected by population, urban/industrial activity, agricultural biomass burning, spring dust, topography and humidity. τ_0.55-fine in eastern China is significantly higher than in western China. Distribution of τ_0.55-coarse reflected the influence of spring dust and urban/industrial pollution. The overall AOD in summer was higher than that in winter due to strong photochemical reactions producing secondary aerosols. In northern China, dust contributed to the mean τ_0.55 in spring months. In some places, aggregated precipitation in the summer months caused a pronounced drop in the temporal profile of AOD. Coal combustion, industrial emission and vehicle exhaust produced coarse aerosols, while fine aerosols are mainly dominated by secondary particles. Smoke from open-fire straw burning produced fine aerosols in the harvest season.     

Model study of tropospheric composition response to NOx and CO pollution

The effect of NO_x and CO pollution on other important atmospheric gases from 0–16 km in the northern temperate zonal belt is calculated using a 2-D (altitude–longitude) channel photochemical model with climatic zonal and vertical fixed transport. The geographical inhomogeneities of the NO_x and CO large-scale surface releases are modeled. The distinction between NO_x and CO fluxes from the oceanic and land surfaces and those from areas with various pollution source intensities is considered. NO_x and CO emissions from world transport aviation engine exhausts and the NO source from lightning discharges are also included. Model results are analyzed and compared with observational data for nitrogen compounds, carbon monoxide, and ozone. The dependence of the spatial and temporal hydroxyl distribution on the carbon monoxide (as the main destroyer of OH) concentration field is analyzed and discussed.     

Comparison analysis of global carbon monoxide concentration derived from SCIAMACHY,AIRS, and MOPITT

Observations of carbon monoxide (CO) retrieved from Scanning Imaging Absorption SpectroMeter for Atmospheric Chartography (SCIAMACHY), Measurement of Pollution in the Troposphere (MOPITT), and Atmospheric Infrared Sounder (AIRS) are compared in this article. To better validate the retrieved data from SCIAMCHY, AIRS, and MOPITT, six surface stations at different locations and with various elevations were chosen. The results show these three instruments can all reflect CO spatial distribution well and show same temporal variations of CO concentration as well as six surface station measurements. MOPITT and AIRS have similar retrieval results with correlation coefficients being mostly over 0.70, except for a sixth field station on Crozet Island. The three satellites all have the ability to monitor CO concentration change on land, but SCIAMCHY results show a relatively larger bias than MOPITT and AIRS in low CO concentration areas because of systematic error.     

MATCH对中国地区2006年气溶胶光学厚度分布特征的模拟研究

利用2006年NCEP/NCAR再分析资料驱动大气化学传输模式MATCH （Model of Atmospheric Transport and Chemistry）,模拟了中国地区气溶胶光学厚度的分布及其季节变化特征,并与MODIS（MODerate resolution Imaging Spectro-radiometer）卫星产品MOD08_M3和中国太阳分光观测网CSHNET（the Chinese Sun Hazemeter Network）的观测资料进行了对比和验证。在此基础上,研究得出,2006年中国的华北、华中和华南地区是气溶胶光学厚度的高值区,青藏高原和东北地区是低值区。在中国的华北、华中、华南和西南等大部分地区,硫酸盐气溶胶产生的光学厚度所占的比重较大,其次为有机碳气溶胶,黑碳气溶胶和海盐气溶胶所占比重较小。     

2001~2018年我国热异常点时空分布特征研究

基于2001~2018年MODIS标准产品,研究了我国及七大区域热异常点的时空分布特征。结果表明：空间分布上,热异常点主要分布在除西北、西南之外的大部分地区;年际趋势上,2001~2014年间热异常点数量持续上升,年均增长率为15.01%,2015年后逐年下降,年均下降率为14.96%。月季尺度上,热异常点在春、秋季节出现最为频繁（春：551 716个,秋：416 698个）,春、秋季相对在东北地区分布最多（春：164 898个,秋：186 727个）,东北地区月均数量10月最高（118 274个）;夏季热异常点数量最低（290 793个）,多分布于华东地区（120 455个）,华东地区月均数量6月最高（76 465个）;冬季数量为358 483个,且在华南地区分布最多（108 209个）,华南地区月均数量1月最高（37 770个）。研究有助于掌握我国典型区域的森林、草原火灾,以及由于秸秆焚烧、工业排放等引起热异常的变化情况,进而为区域灾害防治和环境监测提供技术支撑。     

NASA astronaut photography depiction of the spatial and temporal characteristics of biomass burning

NASA astronaut photographs of the Earth's surface, in the Space Shuttle Earth Observation Photographic database, have been examined for their ability to provide information on remote sensing of temporal and spatial distributions of biomass burning. Over 4554 photos of biomass burning are identified in a dataset containing 347 678 photos accumulated since 1961. Distributions of the entire database, and of the biomass burning photos it contains, are displayed by mission, month, year, season, latitude and hemisphere. The relative frequency of biomass burning photos was determined by removing the effects of the number of days in space and the number of photos taken. Distributions of the photos of burning are shown in relation to characteristics of global climatic and vegetation characteristics which favor biomass burning. The strengths and weaknesses of the photographic database as a tool for remote sensing of biomass burning are also discussed briefly.     

基于MODIS数据的华北地区秸秆焚烧监测

秸秆焚烧给我国城乡生态环境造成巨大损害,利用遥感手段监测秸秆焚烧能够为禁烧治理工作提供有效的数据支持。“背景对比火点探测算法”(the Contextual Fire Detection Algorithm)是目前精度较高的自动探测算法,但固定的阈值参数难以适用于不同地区和不同的监测对象,因此依据实际观测情况对其中的关键参数和阈值进行了适当调整,以更好地监测中国地区的火点。基于EOS/Terra卫星的MODIS数据,利用调整阈值后的算法对我国华北地区2007年5月至8月的秸秆焚烧状况进行了遥感监测,监测精度能够满足实际业务化监测的需要。进一步结合IGBP地表分类数据,将火点像元分成秸秆焚烧、林火和草原火等3种生物焚烧类型,并分别对其亮度温度等多个参数进行了统计分析,在此基础上讨论了根据火点辐射特性判断火点类别的可行性,提出在目前,地表分类数据对于判断火点类别仍是必要的。     

21世纪初中国农作物与自然植被物候时空差异

利用离散小波方法对2001~2012年MODIS EVI时序数据进行平滑,基于动态阈值法提取我国植被物候信息,探讨农作物和自然植被物候的时空变化特征。结果表明:(1)我国第一季农作物开始、峰值和结束日期主要以华北平原为中心随海拔的上升而推迟,而自然植被物候更早20d左右,且随海拔的上升先推迟后提前;(2)物候在时序上有显著变化的第一季区域,43.98%开始日期、52.83%峰值日期呈现提前趋势,多在开始晚、结束早的西南区及东北与内蒙古交界处,其余区域开始、峰值日期及81.80%结束日期呈推迟趋势,发生在开始早、结束晚的黄土高原及双季农作区;农作物物候推迟幅度小于自然植被。