Merging AVHRR and SMMR data for remote sensing of ice and cloud in polar regions

Abstract

Multispectral data from the Advanced Very High Resolution Radiometer (AVHRR) were digitally processed and merged with Scanning Multichannel Microwave Radiometer (SMMR) imagery. Five channels of AVHRR data, four channels of SMMR brightness temperatures and SMMR-derived ice concentration and ice type were co-registered to a polar stereographic grid. The merged data sets are currently being used in combination with meteorological information for integrated studies of clouds and sea ice.     

基于GNSS-R极地海冰测量方法的研究

全球卫星导航系统(GNSS)在经历了将近50年的发展后,已经在国际上取得了相当大的影响,GNSS在经济发展和人类生活方面有着很重要的作用。随着温室气体的排放,全球温室效应,冰川融化,使得越来越多的国家开始重视对海洋的监测。文章以欧洲空间局(ESA)实验数据为数据来源,利用电磁信号在不同的介质表面反射产生的电磁特性变化作为理论依据,论证利用海冰的幅度极化比来监测海冰的形成和消融过程是否可靠。分析结果显示,信号的幅度极化比与海冰在海洋中的覆盖率有着很强的相关性。     

Pattern recognition in satellite monitoring of water and ice surfaces

A system for classifying satellite data for solving problems of space monitoring of hydrological objects is described. The system involves automatic classification and classification with training algorithms.     

Cloud track winds in the polar regions from sequences of AVHRR images

Abstract

A new method is described for obtaining information on the high latitude upper level wind field through the production of cloud motion vectors from sequences of images from polar orbiting satellites. The vectors are produced using sets of three calibrated, 11 μm AVHRR images of the polar regions from successive orbits of the TIROS-N series satellites. Two schemes have been developed for the generation of vectors based on manual and automatic techniques coupled with manual quality control. Case studies have shown that, provided the images are accurately registered and the cloud tracers are carefully selected, useful vectors may be derived.     

Satellite remote-sensing monitoring of a railway construction project

Current satellite remote-sensing technologies enable the timely and detailed monitoring of human activities on the Earth’s surface. Sub-metre spatial resolution satellite images can picture the ongoing works of railway and highway construction. The synoptic view of satellite images is useful to assist the monitoring and management of such construction projects. In this article, we present an integrated remote-sensing change detection framework applied to monitoring the Light Rail Transport construction in Kuala Lumpur, Malaysia, using sub-metre optical remote-sensing images, Pleiades. Focusing on the known local area surrounding a construction site, the recognition process starts from the completion stage, checking conditions based on pre-defined rules, applying the recognition process corresponding to that stage, or moving to the immediately preceding stage if appropriate. The process ends when a new stage is identified and recorded into a spatio-temporal database or it reaches the previously detected stage as retrieved from the database. The experiment proved the effectiveness of the proposed framework, with an overall accuracy of about 80% and a low false detection rate. The proposed framework can be extended to monitor other similar scheduled works. Future studies will integrate multi-sensor satellite images including synthetic aperture radar images to expand further the practicality of the framework.     

Satellite monitoring of boreal forest phenology and its climatic responses in Eurasia

The fragile ecosystems in boreal Eurasia are sensitive to global climate change. Land surface phenology provides an important tool for us to better understand the current status of boreal forest and its climatic responses in this remote zone. This study utilizes the new-generation AVHRR GIMMS NDVI3g products in 1982–2011 to extract four phenological metrics in the study region, including start of season (SOS), end of season (EOS), season length (LOS), and middle of season (MOS). Linear and Mann–Kendall trend analyses are performed to examine their spatiotemporal patterns and relationships with climatic variables assisted with the Climate Research Unit re-analysis climatic data sets. While advanced spring greening is observed in agreement with past studies, our results reveal that the SOS advance mostly occurs in mixed forests in southern Eurasia. More importantly, this study extracts the opposite trends for the end of season – advanced EOS in coniferous forests above 60°N and delayed EOS in mixed forests below. Overall, temperature in May–October has consecutively increased in the past 30 years. Precipitation has also increased but with a fragmented pattern. The advanced SOS across Eurasia is highly correlated with a warmer spring (April and May) in Eurasia. The EOS has a strong, negative relationship with fall precipitation (September). Further investigation is suggested to examine the opposite EOS trends and their environmental/ecological consequences in different forest zones of boreal Eurasia.     

Rapid coverage of regions of interest for environmental monitoring

Intelligent Service Robotics - We present a framework for rapidly determining regions of interest (ROIs) from an unknown intensity distribution, particularly in radiation fields. The vast majority...     

Operational use of ERS-1 SAR images in the Canadian ice monitoring programme

ERS-1 SAR images have been used to monitor sea ice in the Canadian east coast and the Gulf of St. Lawrence since December 1992. Operational ice parameters were obtained, in near real-time, through visual image analysis. The information was incorporated in standard daily operational products. Further analysis was conducted later to evaluate the data utility. The images are remarkably useful in discriminating between new ice and water and in delineating ice edges. Structural information of ice surface is usually smeared. Distinction between young ice and first-year ice types, based on backscatter alone, is not reliable. Rules for image interpretation were developed. They are mainly based on structural information in images, ancillary data on weather, and recent and historical ice records. Limitations on data utilization are explained in relation to the sensor and orbit parameters. An insight into operational requirements and their relation to SAR observations is presented.     

Vision-based surveillance system for monitoring traffic conditions

Multimedia Tools and Applications - With the rapid advancement of sensing technologies, it has been feasible to collect various types of traffic data such as traffic volume and travel times....     

Satellite passive microwave remote sensing for monitoring global land surface phenology

Vegetation phenology characterizes seasonal life-cycle events that influence the carbon cycle and land-atmosphere water and energy exchange. We analyzed global phenology cycles over a six year record (2003-2008) using satellite passive microwave remote sensing based Vegetation Optical Depth (VOD) retrievals derived from daily time series brightness temperature (T_b) measurements from the Advanced Microwave Scanning Radiometer on EOS (AMSR-E) and other ancillary data inputs. The VOD parameter derives vegetation canopy attenuation at a given microwave frequency (18.7 GHz) and varies with canopy height, density, structure and water content. An error sensitivity analysis indicates that the retrieval algorithm can resolve the VOD seasonal cycle over a majority of global vegetated land areas. The VOD results corresponded favorably (p < 0.01) with vegetation indices (VIs) and leaf area index (LAI) information from satellite optical-infrared (MODIS) remote sensing, and phenology cycles determined from a simple bioclimatic growing season index (GSI) for over 82% of the global domain. Lower biomass land cover classes (e.g. savannas) show the highest correlations (R = 0.66), with reduced correspondence at higher biomass levels (0.03 < R < 0.51) and higher correlations for homogeneous land cover areas (0.41 < R < 0.83). The VOD results display a unique end-of-season signal relative to VI and LAI series, and may reflect microwave sensitivity to the timing of vegetation biomass depletion (e.g. leaf abscission) and associated changes in canopy water content (e.g. dormancy preparation). The VOD parameter is independent of and synergistic with optical-infrared remote sensing based vegetation metrics, and contributes to a more comprehensive view of land surface phenology.     

Satellite monitoring of phytoplankton in the East Mediterranean Sea after the 2006 Lebanon oil spill

Multi-source remote-sensing data were used to study the aftermath of the 2006 Lebanon oil spill: Moderate Resolution Imaging Spectroradiometer (MODIS) 250 m data and advanced synthetic aperture radar (SAR) images were used to delineate the extent of the oil spill; QuikScat data were used to derive the wind field; and MODIS Ocean Colour data were used to demonstrate the variability of chlorophyll-a concentration (Chl-a) and sea surface temperature (SST). No significant changes were found in marine phytoplankton in the first few months after the oil spill. However, a big phytoplankton bloom was observed after 10 months, when Chl-a increased from 0.1 to 1.0 mg m^–3. After considering the time-series variability of Chl-a and SST and the spatial variability of Chl-a and bathymetry, we concluded that this phytoplankton bloom was probably related to the Lebanon oil spill.     

Improved confidence regions for a mean vector under general conditions

In this paper, we propose two different confidence regions for a mean vector under general conditions when the population of interest is nonnormal and the sample size is moderate. It is shown that both confidence regions will improve the accuracy of the approximation in the sense that the coverage error is of order o(n^-1). Monte Carlo examples are demonstrated to show the performance with comparison to the classical methods.     

Satellite observations of the circulation east of the Mississippi Delta: Cold-air outbreak conditions

Examination of 12 years of Landsat multispectral scanner images shows a recurrent pattern of westward flow immediately south of the Mississippi-Alabama barrier islands under northerly winds. Such flow patterns are also seen under similar conditions in imagery from the Advanced Very High Resolution Radiometer (AVHRR) of the NOAA-series satellites. The flow enters Chandeleur Sound between Ship Island and the northern end of the Chandeleur Islands. It appears to be driven by northerly winds, which force water south through the ChandeleurBreton Sound, drawing water in from the shelf region south of the Mississippi-Alabama barrier islands. These observations on circulation can be simply explained assuming linear dynamics. These two operational satellite systems are accumulating valuable records of coastal circulation patterns under clear-sky conditions.     

Some concepts for precise estimation of deformations/rigid areas in polar pack ice based on time series of ERS-1 SAR images

This paper describes concepts for an algorithm using pairs of satellite SAR imagery to estimate precisely rigid areas and deformations in polar ice fields. The idea is first to produce a sparse sampling of the ice displacement and then identify rigid subsets of this sparse sampling. The algorithm tunes the position parameters of the images using those of these subsets best fitting the model of rigid motion (shift/rotation). Then the algorithm identifies rigid areas again and so on iteratively improving the identification of rigid areas and the relative geographical positioning in the images. The last step is to classify each pixel in the images as included in one of the given rigid areas or, perhaps, not included in one of these areas.     

Classification of new-ice in the Greenland Sea using Satellite SSM/I radiometer and SeaWinds scatterometer data and comparison with ice model

In the ice covered waters of the Greenland Sea the polarisation ratio of QuikSCAT SeaWinds Ku-band (13.4 GHz) scatterometer measurements and the polarisation ratio of DMSP-SSM/I 19 GHz radiometer measurements are used in combination to classify new-ice and mature ice. In particular, the formation of the new-(frazil/pancake)-ice ‘Odden’ (8° W, 75° N) March 11th-18th, 2001, is used in the study. The results of the ice cover classification in the Greenland Sea are compared to model parameters from a sea ice model. The classification of each ice pixel is performed using its backscatter and radiative properties as reflected in the polarisation ratio. Our results based on these comparisons show that the transformation into older mature (sheet) ice occurs within 5-10 days. During one day the new-ice cover increased by 33 000 km². The new-ice appears in March 2001 as a peninsula (maximum extent 56 000 km²) appended to the belt of older ice drifting along the East Coast of Greenland. These results are consistent with the ice model and with Radarsat images. Furthermore, using the ice model it is demonstrated that the new-ice/mature ice threshold in the classification corresponds to the physical transition of the ice cover from pancake ice to a consolidated young-ice sheet. The classification of each pixel into ice or water is done using two scatterometer parameters, namely the polarisation ratio and the daily standard deviation of the backscatter.     

Robust Satellite Techniques for oil spill detection and monitoring using AVHRR thermal infrared bands

In this article, a new satellite technique for oil spill detection and monitoring is fully presented and discussed. It is based on the general RST (Robust Satellite Techniques) approach applied to Advanced Very High Resolution Radiometer (AVHRR) observations in the thermal infrared region of the electromagnetic spectrum. The proposed approach, which exploits the analysis of multi-temporal satellite records, seems to be able to detect the anomalous signals on the sea due to the oil polluted areas with excellent reliability (0% of false alarms) and good sensitivity in different observational conditions. Its performances have also been evaluated in comparison with another well-known AVHRR approach, analysing the spill event which happened during the Gulf War off the Kuwait and Saudi Arabia coasts in January 1991. The results confirm the reliability of the proposed approach which promises to offer new economically sustainable opportunities for building a near-real-time monitoring system for oil spills on a global scale. Moreover, in order to further assess the exportability of the proposed approach in different observational and environmental conditions, outcomes obtained by applying it to the Seki–Baynunah event affecting the Gulf of Oman in March 1994 are also shown.     

A robust device for large-scale monitoring of bar soap usage in free-living conditions

This work reports the development and evaluation of a robust and easily deployable soap use logging device. The waterproof device contains motion and sound sensors and can be fully embedded in commercial bar soap. At rest, the device is in a low-power mode and the recording of data is triggered by vibrations measured by a tilt switch. Monitoring soap usage is used to support behaviour change interventions, with the aim to reduce contact diseases. Following the algorithm development under laboratory conditions, we evaluate the performance of the logging device under free-living conditions in 58 low-income households in India. In addition to the measurement by logger soaps, washing activity was recorded by observers. These data allow us to quantify the error of soap use detection. Further, the study data are used to train and evaluate an algorithm for the discrimination of soap use associated with hand and body wash. The results show that the soap logger provides an unobtrusive and objective measure of free-living soap usage. The analysis of the activity features reveals a novel hygienic habit, which is important information for the design of bespoke interventions.     

Non-destructive and cost-effective 3D plant growth monitoring system in outdoor conditions

Multimedia Tools and Applications - There is a high demand for non-destructive systems in plant phenotyping which should precisely calculate plant growth and structure parameters. In this study,...     

基于DSP和ARM的电气化铁路接触线覆冰监测系统设计

为预防接触线上的冰害事故以及为除冰融冰提供支持,设计了集成视频传输、覆冰厚度测量、导线温度测量、现场微气象采集的接触线覆冰监测系统。介绍了由控制单元和测量传感器组成的监测系统结构,简略阐述了微气象传感器的选择、无线导线测温传感器的设计和摄像机电磁屏蔽与防冻设计。重点描述了基于图像处理的控制单元的软硬件设计,研究应用DSP与ARM的HPI接口使DSP兼具视频传输与图像处理的功能,ARM通过EPON传输控制信号与测量数据。使用多阈值下的边缘融合算法优化了基于模极大值的边缘检测算法,并提出覆冰厚度和冰凌长度的计算方法。