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1.
水体对区域气候调节起着极其重要的作用,近几十年间咸海的水位剧烈下降和湖泊面积不断萎缩,势必会对咸海地区的气候产生重要影响,分析咸海地区地表温度的变化对于研究水体与其周边地区地表温度的关系具有重要意义。利用咸海地区中分辨率成像光谱仪（moderate resolution imaging spectroradiometer,MODIS）地表温度产品MOD11A2,基于空间分析法研究咸海面积变化对区域地表温度的影响和作用。结果表明:（1）相比于咸海表面温度,研究区内分别有93%和69%的研究区域日间和夜间地表温度均有上升的变化趋势;（2）咸海对区域地表温度直接影响范围大致在沿湖边界30 km的范围内;（3）随着咸海面积的快速萎缩,各土地覆盖类型区域与咸海的地表温差均呈现上升的变化趋势,咸海的区域温度调节功能逐渐减弱。 相似文献
2.
The principal objectives and methods of a Kazakh government program using remote sensing imagery to study processes of terrain development on the dried floor of the Aral Sea are described. A sketch map of relief-forming processes, compiled from the interpretation of false-color space photographs of the exposed sea floor, as well as multitemporal images obtained over a long period of time, will make it possible to compile cartographic models of terrain development and to forecast the evolution of natural complexes of the desiccated Aral Sea floor. 相似文献
3.
2002年——2011年北极海冰时空变化分析 总被引：7，自引：0，他引：7
基于2002年-2011年AMSR-E海冰密集度数据, 分析了北极海冰的时空变化特征及其原因。结果表明海冰外缘线面积每年减小8.28×104 km2, 下降趋势最快的季节为夏季, 下降速度是1979年-2006年的两倍多, 而且海冰密集度也在降低。2003年、2004年的冰情相对较重, 2007年海冰面积最小。长期冰在2002年-2010年间减少了近30%, 减少的区域主要在波弗特海、楚科奇海、东西伯利亚海、拉普贴夫海、喀拉海以及由这些边缘海向北极方向延伸的北冰洋的广大区域, 长期冰减少的地方大部分为季节性海冰增加的地方。海冰面积与年平均气温之间有显著的负相关关系, 随着全球气候变暖的加剧, 这种减小趋势将会持续。 相似文献
4.
MODIS数据的海洋表面温度反演 总被引：4，自引：0，他引：4
以黄海及东海海域为对象,研究用MODIS数据提取我国海域海洋表面温度的方法,建立了适合于我国海域的MODIS海洋表面温度遥感实用模式。研究表明,此算法的反演精度比较高,用这种模式计算的海面温度可较真实地反映海洋表面温度分布状况。由于同一天可以获取同一地区的上午和下午两景MODIS数据,因此MODIS数据在探测海洋现象方面具有独特的优势。 相似文献
5.
中国东海叶绿素浓度变化分析及其海水温度响应 总被引：1，自引：0，他引：1
海洋叶绿素浓度时空格局分析及与海水温度的响应研究对于海洋资源的开发和保护及赤潮的预防具有重要意义。本文基于2004—2018年东海叶绿素浓度和海水温度数据运用趋势分析及ArcGIS10.2软件,对东海叶绿素浓度作了时空分析研究,并结合海水温度进行了回归分析,以探究叶绿素对海水温度变化的响应机制。结果表明：①东海叶绿素浓度在2004—2018年间没有明显的年际变化特征。年内则随时间上下波动,冬季为波峰,夏季为波谷。离海岸带越近,叶绿素浓度越高。②东海海域海水温度在年际尺度上呈波动式起伏变化。在季节尺度上夏秋两季温度较高,春季次之,冬季最低。从沿海到外海海域海温逐渐升高。③就空间相关性而言,东海海域叶绿素浓度与海水温度整体呈负相关,在不同海域相关程度不同。长江口和外海区域叶绿素浓度与海水温度具有很强的相关性;在沿海区域,由于受到城市环境、经济发展及人类生产生活的影响,海水温度与叶绿素浓度的相关性不明显。 相似文献
6.
Since the collapse of the Soviet Union, the crop cultivation structure in the Aral Sea Basin has changed dramatically, and these changes are worth studying. However, historical crop remote sensing mapping at the watershed scale remains challenging, especially crop misclassification at the cropland edge due to mixed pixels. Therefore, we proposed a field segmentation approach to constrain field edges based on time-series Sentinel-2 remote sensing images and the Google Earth Engine platform and then employed the random forest algorithm to perform crop classification based on time series Landsat/Sentinel-2 images and crop phenology information to produce historical crop maps in the Aral Sea Basin from the 1990s onward. The results showed that the intersection over union between the extracted field edges and in situ-measured field size data was 0.65. The overall accuracy of crop mapping was 95.2% in 2019. Then, we extended our method to historical mapping over the 1991–2015 period with accuracies ranging from 82.8% to 91.3%. Moreover, our method applied to historical mapping works well in terms of accuracy and policy matching. These findings indicate that our method can accurately distinguish cropland edges to reduce classification errors due to mixed pixels. This method is promising for solving the cropland edge problem for historical crop mapping in the Aral Sea Basin and can potentially provide a reference for historical crop classification in other watersheds of the world. 相似文献
7.
中国近海1992～1998海平面变化监测与分析 总被引：14，自引：1，他引：13
利用Topex/Poseidon和ERS-1卫星测高资料采用“共线”法计算出1992-10～1998-06中国近海海域海平面及其变化。在扣除T/P卫星测高仪的零点漂移影响后,发现与全球海平面上升率(+2.1±1.3)mm/a相比,不同海域的海平面变化趋势大不相同,黄、东、南海的海平面年变化率分别为：(+3.44±0.61)mm/a,(+3.12±0.47)mm/a,(-1.41±0.48)mm/a。从海平面变化异常中可以看出1993,1994,1997～1998年3次El Nino异常对中国近海海域海平面的影响是南海海域最大,东海次之,黄海最小。除了对海平面进行传统的频谱分析外,还进行了多分辨率的小波分析,还发现在上述3个海域中除了年周期变化较为稳定外,半年及季节(100 d)周期项存在着时间漂移。此外,在上述3个海域还存在着明显的两个月(62 d)周期的变化,其激发原因在此做了初步探讨。 相似文献
8.
海冰微波辐射传输模式和实验研究 总被引：3，自引：0，他引：3
海冰是影响地球热循环的重要因素。以海冰和海水的微波热辐射为源,并通过位于海面遥感海冰的３层分层介质系统的分析,取得中间介质厚度与所接收到的辐射亮温有如下模式：ＴＢ＝Ａ＋Ｂｅ－ＣＤ。其中Ａ,Ｂ,Ｃ与遥感系统的极化,使用角度和角频率有关,可以通过实际地面的海冰测试试验获得。该模式符合电磁场在有损介质中的传播特性,反映出被动微波遥感所接收到的能量与传播距离的关系。近几年来,根据该模式,使用４个频段微波辐射计在地面进行实测（入射角为０°）,在飞行中使用３个频段,结果空中和地面基本符合。实践证明其模式是正确的可行的。文中给出在辽东湾测得航线上的冰厚度分布和亮度温度与冰厚度的统计曲线。最后指出影响测量并限制对厚度识别的几种因素。 相似文献
9.
Emad Ghaleh Noei Mahdi Hasanlou Mohammad Ali Sharifi 《Journal of the Indian Society of Remote Sensing》2018,46(12):2093-2106
Seafloor topography certainly has an impact on ocean circulation in different ways. Due to this assumption, the sea surface currents calculated by optical flow (Horn–Schunck) and geostrophic currents methods are analyzed to observe this impact. Pair of sea surface temperature imageries, calculated sea surface height and sea level anomaly are showed beside depth map in areas with meaningful bathymetric features such as underwater mountains and pools. The reason for the formation of some eddies in the Caspian Sea and Indian Ocean is concluded from the location of pools and knolls. In this study, in addition to introducing new time span for calculating geostrophic currents, Ocean Surface Current Analyses Real-Time (OSCAR) currents are applied to validate our estimated currents. Variety of products such as sea surface temperature imageries, OSCAR currents, depth map, calculated results like sea level anomaly and absolute dynamic topography and estimated currents via optical flow and geostrophic currents have been collected in this paper to make very detailed investigation on depth effect on mentioned water parameters. Results show that impacts of knolls and pools are meaningfully clear in optical flow and geostrophic currents in shaping and rationing water motions. 相似文献
10.
无源微波遥感技术在海冰测厚中的应用研究 总被引：12，自引：0，他引：12
In recent years, microwave radiometry
has been developed as a powerful technique for remote Sensing of Sea ice in China. Since
1986 the thermal emission from sea ice in Liaodong Bay and Bohai Bay has been measured by
multi-frequency microwave radiometers designed by Changchun Institute of Geography,
Academia Sinica. 相似文献
11.
全极化微波辐射计对环境参数敏感性分析 总被引：2，自引：0，他引：2
为衡量全极化微波辐射计各通道对不同环境参数的探测能力,在构建全极化微波辐射传输正演模型的基础上,采用敏感性分析的方法,在固定背景场条件下,对全极化微波辐射计不同频率、各极化通道亮温对海面风速、海面风向、海面温度、大气水汽含量和云中液态水含量等重要环境参数的敏感度进行了分析和量化计算,对正演模型仿真亮温、星载全极化微波辐射计Wind Sat实测亮温相对于真实背景场参数、NCEP分析场资料和TAO/TRITON浮标实测海面风场数据的敏感性进行了分析。分析结果验证了全极化微波辐射计对海面风场的观测能力,衡量了上述重要环境参数对星载全极化微波辐射计各通道的单独影响程度,为中国自主研制全极化微波辐射计时通道指标设计、环境参数反演通道选取及算法提供支持。 相似文献
12.
Anant Parekh Abhijit Sarkar M. Ravichandran 《Journal of the Indian Society of Remote Sensing》2005,33(1):121-126
Multi-channel Scanning Microwave Radiometer (MSMR) onboard 1RS P4 (Oceansat I) measured Brightness Temperature data of the
different bands are found sensitive to the surface and the overlying atmosphere to different degrees. A judicious combination
of multi-channel data can provide such oceanic/atmospheric parameters as surface wind speed, sea surface temperature, water
vapour in the marine atmosphere, etc. This paper highlights results obtained in relation to surface wind speed. Co-location
and concurrence of several ocean data buoys in the Arabian Sea with MSMR observations allowed empirical construction of D-matrix
coefficients for surface wind speed. With both MSMR and the Arabian Sea buoys functioning for the period of one and a half
year (June, 1999 to December, 2000) without interruptions provided a large database. All channels are found to exhibit moderate
sensitivity to surface wind speed. MSMR data in the immediate vicinity (within 150 km) of the buoy locations and within a
time window of one hour were used. A multi-channel linear equation for surface wind speed was subsequently derived. The equation
was subjected to tests with independent data set for the period January - June 2001 over the Arabian Sea and found to be moderately
accurate. The empirical equation is expected to be useful for regional applications over the Arabian Sea and over regions
closer to west coasts, which might have been flagged out in the operational geophysical data stream. An interesting subset
of data revealed the wind signatures of the May 2001 cyclone in the Arabian Sea. 相似文献
13.
Kamlesh P. Lulla Cynthia A. Evans Michael R. Helfert Vance D. Brand Guy S. Gardner John M. Lounge 《国际地球制图》2013,28(4):71-80
The article describes methodology of space monitoring of the existing landscapes as it is practised in the CIS (former USSR). Different points of mew are presented concerning environmental monitoring as well as the aspects of its practical organization. The objectives of automation of the ecological data acquisition, storage and processing are also dealt with; necessity of geographic information systems creation is substantiated. Experience gained in the operation of geoinformation systems is considered with plans on geo‐information base development for the needs of geographical and ecological studies of the CIS landscapes. Practical experience with case studies on identifying and mapping the ecological disaster zones is described in the Aral Sea basin and the Kyzyl Kum desert. 相似文献
14.
首先利用重力恢复与气候实验（gravity recovery and climate experiment,GRACE）卫星重力、卫星测高和海洋温盐数据分析了2003-2012年间南海海水质量的变化特征,进而结合海洋和气象资料探讨了厄尔尼诺和南方涛动（El Ni?o-Southern Oscillation,ENSO）、净淡水通量、海水体积输送和陆地径流在此期间对南中国海海水质量变化的影响。研究结果表明,南海海水质量变化主要受海面净淡水通量和海水体积输送的联合调制影响,周边陆地径流对其影响有限。南海海水质量季节性变化显著,且具有明显的长期增加趋势;ENSO通过改变降水和黑潮自吕宋海峡流入南海的水量影响南海海水质量,使得南海海水质量存在着显著的具有ENSO特征的年际变化。 相似文献
15.
北极海冰表面的积雪深度是重要的地球物理变量, 是研究物质与能量平衡、计算海冰厚度的重要参数。为减小不同被动微波传感器观测数据的系统误差, 对国防气象卫星计划(Defense Meteorological Satellite Program, DMSP)F17-SSMIS与F13-SSM/I重叠期亮度温度数据进行交叉定标, 建立4个频段48个月尺度定标模型, 并与传统年尺度定标模型进行比较和优选, 在此基础上估算并分析2003-2014年北极一年海冰表面积雪深度变化。结果表明:19H、19V、22V、37V频段1~5月的月尺度模型决定系数高于传统年尺度拟合模型; 2003-2014年, 北极一年海冰表面积雪深度总体呈现下降趋势, 同时积雪深度存在明显的周期性变化, 每年7月积雪深度最小, 9月最大; 东西伯利亚海、拉普捷夫海和巴伦支海海冰表面积雪深度呈现减少的趋势。 相似文献
16.
17.
以北极为研究区,使用CryoSat-2数据,利用现有海冰厚度卫星测高研究中4种主流算法(Laxon03算法、Kurtz09算法、Yi11算法和Laxon13算法)分别对北冰洋海冰厚度进行估算,并将估算结果与研究区IceBridge机载激光测高冰厚数据进行了比较,探索各算法海冰厚度估算的差异,寻找最优的估算算法,为估算长时序海冰厚度提供基础和参考。结果表明,4种算法估算的海冰厚度空间分布较为一致,但不同算法估算的结果差异较大,可达0.476 m;4种算法估算结果大小依次为Laxon03算法、Yi11算法、Laxon13算法、Kurtz09算法;4种算法估算的平均海冰厚度差异,在北极波弗特海海域最大,其次是北极中心海域、格陵兰和挪威海;Laxon13算法估算结果相对于IceBridge观测结果与其他算法相比,具有最小的平均偏差和均方根误差,是卫星测高估算海冰厚度的最优算法。 相似文献
18.
An effective methodology for Bohai Sea ice detection based on gray level co-occurrence matrix (GLCM) texture analysis is proposed using MODIS 250 m imagery. The method determines texture measures for sea ice extraction by analyzing the discrepancy of textural features between sea ice and sea water. Sea ice extent and outer edge are recognized accurately by texture segmentation owing to significant differences in texture statistical features between ice and water. The texture analysis method can properly eliminate perturbations on sea ice extraction due to suspended sediment. It effectively solves the problem of spectral confusion and sea ice misassignment in the conventional gray-threshold segmentation and ratio-threshold segmentation methods. The method eliminates the need for threshold range setting for sea ice segmentation. Taking the Bohai Sea as an example, the results of the proposed method are validated using co-temporal HJ1B-CCD 30 m imagery by visual interpretation, and the accuracy of the method are evaluated using confusion matrix. The results show that the proposed method is superior and more reliable for sea ice detection compared to conventional methods, providing an ideal tool for precise sea ice extraction. 相似文献
19.
A multidimensional model of a shelf-zone ecosystem (based on conditions along the northwestern portion of the Black Sea) is elaborated and tested to determine the specific relationships between biochemical ecosystem components responsible for light absorption and scattering in the sea and the spectral composition of the returned radiant energy (e.g., diffuse reflectance values). The ultimate purpose is to derive a body of information making it possible to ascertain chemical and biological conditions in sea water from spectral signatures. Translated by Edward Torrey, Alexandria, VA 22308 from: Kosmicheskiye metody izucheniya biosfery [Remote Sensing Methods in the Study of the Biosphere]. Moscow: Nauka, 1990, pp. 111–116. 相似文献
20.
本文利用多源遥感数据从不同空间尺度对2004年至2012年间北极地区新冰进行了提取并对其范围变化进行了分析。统计分析结果表明,北极海冰总体覆盖面积与北极近地表气温的变化呈反比;新冰覆盖面积的变化与海冰总面积的变化相比较缓慢;北极各个区域新冰覆盖范围的变化与各区域近地表温度的变化有较大的关联。 相似文献