基于MODIS数据的长株潭地区城市热岛时空分析   总被引：7，自引：1，他引：6  

历华  曾永年  贠培东  黄健柏  邹杰 《测绘科学》2007,32(5):108-110,116

基于MODIS影像,采用分裂窗算法反演的地表温度对长株潭地区城市热岛空间分布与季相变化特征、影响因子进行定量研究。结果表明,长株潭地区春季和夏季存在明显的城市热岛效应,而冬季和秋季城市热岛并不明显;地表覆盖类型对城市热岛的影响十分明显,长株潭地区春、夏、秋季植被绿地状况与城市热岛呈现明显负相关分布,其中以夏季最为明显,夏季地表温度与NDVI相关系数的平方R2达到0.8193,即植被覆盖对城市地表温度的影响显著。因此,城市植被的分布与季节变化影响着城市热岛的强度与时空分布,揭示出植被绿地对降低城市热岛效应具有重要的作用,大范围的绿地建设能有效降低城市热岛效应。  相似文献   

一种工业热源提取方法:利用温度特征模板的BP神经网络     

李博  范俊甫  韩留生  孙广伟  张大富  张盼盼 《地球信息科学学报》2022,24(3):533-545

针对年尺度热异常数据提取工业热源的方法存在数量和空间精细化程度不足的问题,使用VIIRS Active Fire数据,提出了一种基于温度特征模板的BP神经网络工业热源提取方法。该方法以京津冀及周边地区为试验区,首先,根据工业热源空间聚集性特征,使用OPTICS算法划分热源对象;其次,根据热源的热辐射特征,构建工业热源与非工业热源温度特征模板;最后,以温度特征模板、热源统计特征等作为参数,使用BP神经网络提取工业热源对象。结果表明：① 本文提出的基于温度特征模板的BP神经网络算法的工业热源提取精度达到了96.31%,与时间滤波、逻辑回归方法相比较,工业热源提取精度分别提高了8.45%、7.53%;② 2015—2020年京津冀及周边地区6省市工业热源数量整体减少了27.46%;河北省工业热源对象数量和热异常点数量年均减少了8.06%和7.44%,相对于其他省市减少幅度最大;山东、天津的工业热源集中度分别提高了25.72%、86.64%,说明两地工业转型升级政策取得较显著成效;③ 唐山、邯郸、吕梁和长治4个城市工业热源对象数量占试验区全部的31.37%,为京津冀及周边地区工业热源主要分布城市;临汾、太原等7个城市工业热源聚集程度和能源消耗程度高于其他城市;北京、周口等11个城市工业热源聚集程度和能源消耗程度低于其他城市;④ 2020年1—5月,京津冀及周边地区工业热异常点数量相对于2019、2021年同期保持不变或增加,新冠疫情对试验区工业热源无显著影响;2020年1、2月武汉工业热异常点数量与2019、2021年同期相比数量减少了66.67%以上,2020年3—5月工业热异常点数量低于2019年同期,2020年1—5月新冠疫情对武汉市工业热源影响显著。该研究反映了京津冀及周边地区工业热源发展的现状及趋势,能够为降低能耗和提高第二产业集中度等相关政策的制定与调整提供有价值的参考。  相似文献   

顾及人群集聚和情绪强度的城市综合活力评价及影响因素     

梁立锋  曾文霞  宋悦祥  邵振峰  刘秀娟 《地球信息科学学报》2022,24(10):1854-1866

城市活力的科学定量评估,能够为城市规划和协调发展提供重要依据,针对城市活力容易忽略居民情感的现状,本文选用百度热力图数据与微博情感分析结果,分别衡量人群集聚强度和情绪强度,并结合TOPSIS方法,提出一种顾及人群集聚和情绪强度的综合活力评估框架。从城市物理环境、经济环境和生态环境3个维度,选择8个关键影响因子,结合地理探测器空间分析方法,探讨影响因子对城市活力空间异质性的影响。结果表明：① 融合人群集聚强度和情绪强度的综合活力评估方法,能够较好反映城市活力空间分异格局;通过对典型样本区域分析,验证了本文提出的城市综合活力评价框架的有效性;② 城市POI密度对城市综合活力的解释力最显著,而植被覆盖度因子对城市综合活力的解释力最弱;但是植被覆盖度因子与其他因子的交互作用,对于城市活力空间异质性的影响力提升最为显著,表明植被覆盖度因子并不是直接作用于城市活力的空间异质性,而是通过耦合空间可达性、POI密度以及建筑密度等影响因子,间接影响城市综合活力的空间分异。  相似文献   

Comparison of heat balance characteristics at five glaciers in the Southern Hemisphere     

Yukari Takeuchi  Renji Naruse  Kazuhide Satow  Nobuyoshi Ishikawa 《Global and Planetary Change》1999,22(1-4)

Ablation characteristics of five glaciers in Patagonia and New Zealand were compared. Investigated glaciers were Tyndall and Moreno in southern Patagonia, Soler and San Rafael in northern Patagonia, and Franz Josef in New Zealand. Micro-meteorological observations were carried out at the glaciers and the heat balance components were estimated. At Franz Josef and Soler glaciers, the sensible heat flux is the largest and the latent heat flux is the second, and they are larger than the net radiation. At San Rafael Glacier, the net radiation is the largest and the latent heat flux is the smallest component, which is similar to Moreno and Tyndall glaciers. Though the latent heat flux is the smallest component at San Rafael Glacier, it is more than twice as large as that at Tyndall Glacier and contributes substantially to ice melting. The ratios of heat balance components were very different among glaciers, but the total heat flux ranged from about 240 to 300 W m⁻² showing little difference among glaciers.  相似文献   

陆面面积平均通量的参数化问   总被引：5，自引：0，他引：5  

牛国跃  洪钟祥  孙菽芬  叶卓佳 《气候与环境研究》1997,2(3):210-221

目前,气候和大气边界层物理研究中一个十分重要的研究方向就是面积平均通量的参数化问题。本文对这一研究方向中存在的问题、可能的解决方法和目前的研究进展情况进行了阐述,简要介绍了非均匀陆面影响的高度及其尺度划分,阐述了混合高度、参考层高度（观测高度和模式第一层高度）、近地层高度、内边界层高度、平衡层高度、粗糙度副层和边界层高度等之间的关系及其在非均匀尺度划分中的作用,并且阐述了整体输送公式在不同尺度的非均匀陆面中存在的问题及相应的可能解决办法。同时还对中尺度的非均匀陆面驱动的一类非经典中尺度环流的参数化,即中尺度通量的参数化问题进行了评述。最后针对内蒙古草原实验和青藏高原实验等具体问题,提出了边界层观测和非均匀陆面参数化方法的几点问题。  相似文献   

Short term variability of Particle fluxes and its relation to variability in sea surface temperature and chlorophylla field detected by Ocean Color and Temperature Scanner (OCTS) off Sanriku, northwestern North Pacific in the spring of 1997     

Toshiro Saino  Shaoling Shang  Yoshihisa Mino  Koji Suzuki  Hideaki Nomura  Sei-ichi Saitoh  Hideo Miyake  Toshiyuki Masuzawa  Koh Harada 《Journal of Oceanography》1998,54(5):583-592

A sediment trap experiment was carried out in conjunction with an over flight of Ocean Color Temperature Scanner (OCTS) on board Advanced Earth Observing Satellite (ADEOS) at 40°N, 143°E off Sanriku in April to May 1997. Short term variability of particle fluxes was examined at depths of 450 m and 600 m from April 6 to May 1 with a sampling interval of two days, and at 450 m with one day interval from 2nd to 10th May. Daily averaged mass flux at 450 m and 600 m was 815 mg m⁻²d⁻¹ and 862 mg m⁻²d⁻¹, respectively. A sharp increase in mass flux was observed during the period from April 26 to April 29 with the highest mass flux of 8 g m⁻²d⁻¹. About 85% of the total mass flux for the entire duration (26 days) was collected within these 4 days. Trapped material during the peak flux period was mainly composed of diatoms dominated byThalassiosira spp. and resting spores ofChaetoceros spp. This suggested that the peak flux was the result of (a) diatom bloom(s) in the euphotic column. Current meter records at 420 m showed that on April 26 and 27, the period when the peak flux was observed, the southwestward current had diminished in strength and changed its direction northwestward. Low current speeds appeared to have enhanced trap efficiency to help form the peak flux. A time series of OCTS Intensive-LAC (Local Area Coverage: Region B) images from mid-March to early May was examined todetect phytoplankton bloom(s). In the March 26th Chl image, high concentration region was restricted to the southwest off Cape Erimo, but spread around the warm core ring (WCR) 93A by April 10. East of the WCR93A, high Chl concentration remained steady until May, but to the west of the WCR93A, Chl decreased rapidly before the 19th of April. From this observation we suspect that the peak flux observed at the end of April originated from a bloom, which ceased on the 17th or 18th of April, in the region north of 40°N and west of 143°E. Taking the current meter records into account, the source region for the trapped material is most likely around southwest of the Cape Erimo.  相似文献   

Net Zooplankton and the biological pump off Sanriku, Japan     

Satoru Taguchi  Toshiro Saino 《Journal of Oceanography》1998,54(5):573-582

Taxonomic composition, size composition, standing stock, and chemical composition of mesozooplankton were determined to examine the contribution of their fecal pellets to the vertical flux of organic carbon at the outside, the edge, and the center of the warm core ring. The warm core ring significantly affects not only their taxonomic composition and size composition but also their standing stock and chemical composition. The zooplankton at the center of the warm core ring was characterized by the absence of carnivores at the top of the size-trophic relation and filter feeding planktonic tunicates at the bottom. Zooplankton carbon biomass at the outside of the ring was one-third less than that at the center of the ring. The vertical flux of fecal pellets obtained from the pellet volume (12.3 mgC m⁻²d⁻¹) contributed 19 to 96% of the flux (13 to 64 mgC m⁻² d⁻¹) estimated from the body carbon and the fecal pellet production rate. The estimated flux of fecal pellets was 6 to 27% of vertical carbon flux (236 mgC m⁻²d⁻¹) determined by the sediment traps. Microscopic determination of fecal pellets and plankton in the sediment trap samples indicated high grazing activity during the sinking process. Those observations might suggest that particles other than fecal pellets contributed significantly to the vertical carbon flux and fecal pellets were settled directly without loss or being recycled within the surface mixed layer.  相似文献   

九龙江口水体中1995年有机物的转移   总被引：1，自引：0，他引：1  

陈松  廖文卓  许爱玉 《台湾海峡》1998,(2)

1995年3个航次调查研究结果表明,九龙江口水体总有机物的含量受悬浮物含量控制。在S＜5的低盐度区,悬浮泥沙和有机物产生明显的絮凝沉降;在S＞5的广阔海域,它们的迁移接近于理想混合。估算得出九龙江河流的入海通量约：悬浮泥沙为9．8×105t／a;总COD为3．2×104t／a,其中溶解态COD为2.1×104t／a,约占2／3,为水体有机物的主要形态,如换算为溶解有机碳,则DOC的平均通量为3．2×104t／a。  相似文献   

青藏高原东部长江流域盆地地表化学剥蚀通量剥蚀速率大气CO₂净消耗率研究   总被引：1，自引：0，他引：1       下载免费PDF全文

秦建华 《沉积与特提斯地质》2008,28(1):1-6

2000-2002年期间,笔者对青藏高原东部长江流域溶质载荷分别进行了取样分析并对流域盆地化学剥蚀通量、剥蚀速率和大气CO2净消耗率进行了计算。结果表明,流域盆地化学剥蚀速率以河源区楚玛尔河最高为2.34×10^6mol/a/km^2,沱沱河最低为1.40×10^6mol/a/km^2,四大支流雅砻江为1.69×10^6mol/a/km^2,金沙江为1.74×10^6mol/a/km^2,大渡河为1.57×10^6mol/a/km^2,岷江为1.88×10^6mol/a/km^2;流域盆地ФCO2估算结果以大渡河最高为101.81×10^3mol/a/km^2,楚玛尔河最低为7.55×10^3mol/a/km^2,金沙江为44.38×10^3mol/a/km^2,雅砻江为69.64×10^3mol/a/km^2,岷江为81.90×10^3mol/a/km^2,沱沱河为21.90×10^3mol/a/km2^。并对长江流域地表化学剥蚀速率主要控制因素进行了讨论。  相似文献   

Crust and upper mantle heterogeneities in the southwest Pacific from surface wave phase velocity analysis     

R. Pillet  D. Rouland  G. Roult  D. A. Wiens 《Physics of the Earth and Planetary Interiors》1999,110(3-4):211-234

Direct earthquake-to-station Rayleigh and Love wave data observed on high gain broadband records are analyzed in order to improve the lateral resolution of the uppermost mantle in the southwest Pacific region. We used data of nine permanent Geoscope and Iris stations located in the southern hemisphere and nine other stations as part of two temporary networks, the first one installed in New Caledonia and Vanuatu (hereafter named Cavascope network) by ORSTOM and the EOST from Louis Pasteur University in Strasbourg (France) and the second one installed in the Fiji, Tonga and Niue islands (hereafter named Spase network) by Washington University in St. Louis (USA). In order to collect more significant details on the surficial structures, we included the analysis of short period waves down to 8 s. A multiple frequency filtering technique has been used to recover phase velocities of Rayleigh and Love waves for selected earthquakes with magnitude greater than 5.5 and with known centroid moment tensor (CMT). About 1100 well-distributed seismograms have been processed in the period range 8–100 s and corrections for topography and water depth have been applied to the observed phase velocities. The geographical distribution of phase velocity anomalies have then been computed using the tomographic method developed by Montagner [Montagner, J.P., 1986a. Regional three-dimensional structures using long-period surface waves. Ann. Geophys. 4 (B3), 283–294]. Due to a poor knowledge of dense, well-distributed, crustal thickness values and corresponding velocity models, we did not perform or speculate on the construction of an S-wave 3D velocity model; therefore, we limited this study to the interpretation of the phase velocity distribution. The location of phase velocity anomalies are well determined and the deviations are discussed within the framework of the geological context and compared with other tomographic models. At long periods, from 40 s to 100 s, our results agree well with most of previous studies: the tomographic imaging shows a large contrast between low and high phase velocities along the Solomon, New Hebrides and Fiji–Tonga trenches. The lowest phase velocity anomalies are distributed beneath northern and southern Fiji basins and the Lau basin (corresponding to the volume situated just above the dipping slabs), whereas the highest values are displayed beneath the Pacific plate and the eastern part of Indian plate downgoing under the North Fiji basin. At shorter periods, our results show that the phase velocity distributions are well correlated with the large structural crustal domains. The use of local temporary broadband stations in the central part of the studied area gives us the opportunity to observe surface waves showing well-dispersed trains, allowing extended velocity measurements down to 8 s although aliasing due to multipaths become important. The continental regions (Eastern Australia, New Guinea, Fiji islands and New Zealand) show low velocities which are likely due to thick continental crust, whereas the Tasmanian, D'Entrecasteaux, and the Northern and Southern Fiji basins are characterized by higher velocities suggesting thinner oceanic crust. Additional analysis including the anisotropic case and S-wave velocity inversion with depth is in progress.  相似文献