Satellite monitoring

卫星监测
  • 文章类型: Journal Article
    曼谷地面沉降,一个紧迫的环境挑战,需要持续的长期政策干预。尽管缓解措施已成功缓解了曼谷内的沉降率,邻近省份的利率继续上升。传统的陆基监测方法在覆盖范围方面存在局限性,气候和社会经济因素的预期非线性贡献进一步使沉降的时空分布复杂化。这项研究旨在为近期(2023-2048)提供未来沉降预测,中期(2049-2074),和遥远的未来(2075-2100),采用干涉合成孔径雷达(InSAR),随机森林机器学习算法,并结合共享社会经济途径-代表性集中途径(SSP-RCP)方案来应对这些挑战。平均视线(LOS)速度为-7.0毫米/年,在大城府记录的最大-53.5毫米/年。所提出的模型表现出良好的性能,产生0.84的R2值,并且没有过拟合的迹象。在所有场景中,在不久的将来,沉降率往往会增加-9.0毫米/年以上。然而,对于中期和遥远的未来,场景说明了不同的趋势。“唯一的城市-LU变化”情景预测将逐步复苏,而其他变化情景表现出不同的趋势。
    Land subsidence in Bangkok, a pressing environmental challenge, demands sustained long-term policy interventions. Although mitigation measures have successfully alleviated subsidence rates within inner Bangkok, neighboring provinces continue to experience escalating rates. Conventional land-based monitoring methods exhibit limitations in coverage, and the anticipated nonlinear contributions of climatic and socioeconomic factors further complicate the spatiotemporal distribution of subsidence. This study aims to provide future subsidence predictions for the near (2023-2048), mid (2049-2074), and far-future (2075-2100), employing Interferometric Synthetic Aperture Radar (InSAR), Random Forest machine learning algorithm, and combined Shared Socioeconomic Pathways-Representative Concentration Pathways (SSP-RCPs) scenarios to address these challenges. The mean Line-of-Sight (LOS) velocity was found to be -7.0 mm/year, with a maximum of -53.5 mm/year recorded in Ayutthaya. The proposed model demonstrated good performance, yielding an R2 value of 0.84 and exhibiting no signs of overfitting. Across all scenarios, subsidence rates tend to increase by more than -9.0 mm/year in the near-future. However, for the mid and far-future, scenarios illustrate varying trends. The \'only-urban-LU change\' scenario predicts a gradual recovery, while other change scenarios exhibit different tendencies.
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  • 文章类型: English Abstract
    根据环境空气质量数据,气象观测资料,和卫星遥感数据,臭氧(O3)污染的时空变化,分析了O3的敏感性及其与海南岛气象因子的关系。结果表明,海南岛西部和北部城市的最大日8-h移动平均值(O3-8h)高于中部,东方,和南方城市。2015年O3-8h最高,2019年O3-8h超标比例最大。此外,O3-8h与平均气温呈正相关(P<0.1),日照时数(P<0.01),太阳总辐射(P<0.01),大气压力,平均风速与降水量(P<0.05)、相对湿度呈负相关。卫星遥感数据显示,2015-2020年海南岛对流层NO2柱浓度(NO2-OMI)和HCHO柱浓度(HCHO-OMI)呈现相反趋势。与2015年相比,2020年NO2-OMI增长了7.74%,HCHO-OMI下降了10.2%。此外,海南岛属于氮氧化物控制区,FNR值在过去6年呈现波动下降趋势,趋势系数和气候趋势率分别为-0.514和-0.123a-1。气象因子与海南岛的FNR值之间存在很强的相关性。
    Based on ambient air quality data, meteorological observation data, and satellite remote sensing data, the temporal and spatial variations in ozone (O3) pollution, the sensitivity of O3, and its relationship with meteorological factors in Hainan Island were analyzed in this study. The results showed that the maximum daily 8-h moving mean (O3-8h) in western and northern cities in Hainan Island was higher than that in the central, eastern, and southern cities. O3-8h was the highest in 2015, and O3-8h exceeding the standard proportion was the largest in 2019. In addition, O3-8h was positively correlated with average temperature (P<0.1), sunshine duration (P<0.01), total solar radiation (P<0.01), atmospheric pressure, and average wind speed and was negatively correlated with precipitation (P<0.05) and relative humidity. The satellite remote sensing data showed that the tropospheric NO2 column concentration (NO2-OMI) and HCHO column concentration (HCHO-OMI) displayed opposite trends in Hainan Island from 2015 to 2020. Compared with those in 2015, NO2-OMI increased by 7.74% and HCHO-OMI decreased by 10.2% in 2020. Moreover, Hainan Island belongs to the NOx control area, and the FNR value exhibited a fluctuating downward trend in the past 6 years, with a trend coefficient and climatic trend rate of -0.514 and -0.123 a-1, respectively. A strong correlation was observed between meteorological factors and the FNR value of Hainan Island.
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  • 文章类型: Journal Article
    随着时间的推移监测海岸线对于快速识别和缓解海岸侵蚀等环境问题至关重要。利用卫星图像进行监测有两大优势,即,全球覆盖范围和频繁的测量更新;但需要适当的方法从此类图像中提取海岸线信息。为此,有一些有价值的非监督方法,但是最近的研究集中在深度学习上,因为它在一般性方面具有更大的潜力,灵活性,和测量精度,which,相比之下,从标记样本的大型数据集中包含的信息中得出。首先要解决的问题,因此,在于获得适合此特定测量问题的大型数据集,这是一项艰巨的任务,通常需要人类对大量图像进行分析。在这篇文章中,我们提出了一种技术,自动创建适合训练机器学习模型的标记卫星图像数据集的海岸线检测。该方法基于卫星照片数据和认证数据的整合,可公开访问的海岸线数据。它涉及几个自动处理步骤,旨在建立尽可能好的数据集,图像包括海洋和陆地区域,和正确的标签也存在复杂的水边(可以是开放或封闭的曲线)。使用独立认证的测量来标记卫星图像,避免了通过视觉检查手动注释它们所需的大量工作,正如文献中的其他作品所做的那样。当考虑到复杂的海岸线时,尤其如此。此外,也消除了由于卫星图像的主观解释而导致的可能错误。该方法被开发并专门用于构建新的Sentinel-2图像数据集,表示为SNOWED;但适用于经过微小修改的不同卫星图像。SNOWED中标签的准确性直接取决于所使用的海岸线数据的不确定性,这在大多数情况下导致子像素误差。此外,SNOWED数据集的质量是通过对图像及其相应标签的随机样本进行视觉比较来评估的,通过训练用于海陆分割的神经模型来显示其功能。
    Monitoring the shoreline over time is essential to quickly identify and mitigate environmental issues such as coastal erosion. Monitoring using satellite images has two great advantages, i.e., global coverage and frequent measurement updates; but adequate methods are needed to extract shoreline information from such images. To this purpose, there are valuable non-supervised methods, but more recent research has concentrated on deep learning because of its greater potential in terms of generality, flexibility, and measurement accuracy, which, in contrast, derive from the information contained in large datasets of labeled samples. The first problem to solve, therefore, lies in obtaining large datasets suitable for this specific measurement problem, and this is a difficult task, typically requiring human analysis of a large number of images. In this article, we propose a technique to automatically create a dataset of labeled satellite images suitable for training machine learning models for shoreline detection. The method is based on the integration of data from satellite photos and data from certified, publicly accessible shoreline data. It involves several automatic processing steps, aimed at building the best possible dataset, with images including both sea and land regions, and correct labeling also in the presence of complicated water edges (which can be open or closed curves). The use of independently certified measurements for labeling the satellite images avoids the great work required to manually annotate them by visual inspection, as is done in other works in the literature. This is especially true when convoluted shorelines are considered. In addition, possible errors due to the subjective interpretation of satellite images are also eliminated. The method is developed and used specifically to build a new dataset of Sentinel-2 images, denoted SNOWED; but is applicable to different satellite images with trivial modifications. The accuracy of labels in SNOWED is directly determined by the uncertainty of the shoreline data used, which leads to sub-pixel errors in most cases. Furthermore, the quality of the SNOWED dataset is assessed through the visual comparison of a random sample of images and their corresponding labels, and its functionality is shown by training a neural model for sea-land segmentation.
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  • 文章类型: Journal Article
    大堡礁(GBR)预计将在2021-2022年南半球夏季经历第六次大规模珊瑚白化事件。在卫星记录(1985年至今)中,预计GBR上的珊瑚漂白水平的热应力将比上一年更早开始。美国国家海洋和大气管理局(NOAA)珊瑚礁观察(CRW)近实时基于卫星的热应激产品被用于调查2021年末早期夏季海面温度(SST)和GBR的热应激条件。截至2021年12月14日,GBR上12周运行窗口(度加热周)中的瞬时热应力(珊瑚漂白热点)和累积热应力的值在卫星记录中是前所未有的。Further,2021年这一天89%的GBR卫星礁像素具有大于0.2摄氏度/周的积极7天SST趋势。背景温度(过去29天的最低温度)高得惊人,2021年12月14日87%的GBR珊瑚礁像素大于1985-2020年任何一年相同29天期间的最大SST。GBR将在2021-2022年夏季开始,积累的热量比以往任何时候都多,这可能会给健康带来灾难性的后果,recovery,以及这个关键珊瑚礁系统的未来。
    The Great Barrier Reef (GBR) is predicted to undergo its sixth mass coral bleaching event during the Southern Hemisphere summer of 2021-2022. Coral bleaching-level heat stress over the GBR is forecast to start earlier than any previous year in the satellite record (1985-present). The National Oceanic and Atmospheric Administration (NOAA) Coral Reef Watch (CRW) near real-time satellite-based heat stress products were used to investigate early-summer sea surface temperature (SST) and heat stress conditions on the GBR during late 2021. As of 14 December 2021, values of instantaneous heat stress (Coral Bleaching HotSpots) and accumulated heat stress over a 12-week running window (Degree Heating Weeks) on the GBR were unprecedented in the satellite record. Further, 89% of GBR satellite reef pixels for this date in 2021 had a positive seven-day SST trend of greater than 0.2 degrees Celsius/week. Background temperatures (the minimum temperature over the previous 29 days) were alarmingly high, with 87% of GBR reef pixels on 14 December 2021 being greater than the maximum SST over that same 29-day period for any year from 1985-2020. The GBR is starting the 2021-2022 summer season with more accumulated heat than ever before, which could have disastrous consequences for the health, recovery, and future of this critical reef system.
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  • 文章类型: Journal Article
    空气动力学直径为10µm或更小的空气颗粒物(PM10)是慢性阻塞性肺疾病(AECOPD)急性加重的主要原因之一。本研究探讨了2014年至2018年Chaharmahal-o-Bakhtiari省遥感PM10与AECOPD的关系。
    根据MODIS传感器处理的161张图像和地面空气质量监测站数据,根据气溶胶光学深度(AOD)对PM10浓度进行了预测和验证。收集并分析了2038例AECOPD患者在研究期间的人口统计信息和肺活量指标。使用SPSS软件分析这两类信息之间的关系。
    PM10与FVC呈显著负相关,FVC%,FEV1,FEV1%,FEF25-75,FEV1/FVC,PEF,和FEF25FVC指数(p<0.05)。结果表明,在2014-2018年期间,PM10的年平均浓度从35到52µg/m3不等。回归模型的结果表明,患者的年龄,体重指数(BMI),PM10浓度是影响两个重要肺活量指数的最大变量,FVC%和FEV1%。在研究期间,AECOPD患者的PM10浓度和数量具有相似的模式。妇女团体,74岁以上年龄组,正常BMI,非吸烟患者对PM10浓度最敏感。
    我们的研究结果提供了关于PM10浓度与AECOPD发病率相关的补充科学信息,并作为影响最重要肺活量测定指标的变量,为当地决策者提供了确定空气污染控制措施和卫生服务优先事项所需的信息。
    UNASSIGNED: Air particulate matter with an aerodynamic diameter of 10 µm or less (PM10) is one of the main causes of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study explored the relationship between PM10 by remote sensing and AECOPD in Chaharmahal-o-Bakhtiari province from 2014 to2018.
    UNASSIGNED: PM10 concentrations were predicted and validated based on aerosol optical depth (AOD) from 161 images processed by MODIS sensor and ground air quality monitoring station data. Demographic information and spirometric indices of 2038 patients with AECOPD were collected and analyzed from the hospital during the studied periods. SPSS software was used to analyze the relationships between these two categories of information.
    UNASSIGNED: There was a significant negative relationship between PM10 and FVC, FVC%, FEV1, FEV1%, FEF25-75, FEV1/FVC, PEF, and FEF25FVC indices (p < 0.05). The results showed that over 2014-2018, the annual mean of PM10 concentrations varied from 35 to 52 µg/m3. The result of the regression model showed that the patient\'s age, body mass index (BMI), and PM10 concentrations were the most affecting variables on the two important spirometric indices i.e., FVC% and FEV1%. The PM10 concentrations and number of AECOPD patients had a similar pattern during the studied period. The women group, age group above 74 years, normal BMI, and non-smoking patients showed the most sensitivity to the PM10 concentrations.
    UNASSIGNED: Our findings provide supplementary scientific information on PM10 concentration related to the incidence of AECOPD and as a variable affecting the most important spirometry indicators by providing local decision-makers information needed to set a priority of air pollution control measures as well as health services.
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  • 文章类型: Journal Article
    CO2 concentration (XCO2) shows the spatial and temporal variation in Iran. The major purpose of this investigation is the assessment of the spatial distribution of carbon dioxide concentration in the different seasons of 2013 based on the Thermal And Near Infrared Sensor for Carbon Observation-Fourier Transform Spectrometer (TANSO-FTS) level 2 GOSAT data by implementing the ordinary kriging (OK) method. In this study, the Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) data from the MODerate resolution Imaging Spectroradiometer (MODIS), and metrological parameters (temperature and precipitation) were used for the analysis of the spatial distribution of CO2 over Iran in 2013. The spatial distribution maps of XCO2 show the highest concentration of this gas in the south and south-east and the lowest concentration in the north and north-west. These results indicate that the concentration of carbon dioxide decreased with the increase of LST and temperature and a decrease of NDVI and humidity in the study area. Therefore, the existence of vegetation has an effective role in capturing carbon from the atmosphere by photosynthesis phenomena, and sustainable land management can be effective for carbon absorption from the atmosphere and mitigation of climate change in arid and semi-arid regions.
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  • 文章类型: Journal Article
    Mountain plants are considered among the species most vulnerable to climate change, especially at high latitudes where there is little potential for poleward or uphill dispersal. Satellite monitoring can reveal spatiotemporal variation in vegetation activity, offering a largely unexploited potential for studying responses of montane ecosystems to temperature and predicting phenological shifts driven by climate change. Here, a novel remote-sensing phenology approach is developed that advances existing techniques by considering variation in vegetation activity across the whole year, rather than just focusing on event dates (e.g. start and end of season). Time series of two vegetation indices (VI), normalized difference VI (NDVI) and enhanced VI (EVI) were obtained from the moderate resolution imaging spectroradiometer MODIS satellite for 2786 Scottish mountain summits (600-1344 m elevation) in the years 2000-2011. NDVI and EVI time series were temporally interpolated to derive values on the first day of each month, for comparison with gridded monthly temperatures from the preceding period. These were regressed against temperature in the previous months, elevation and their interaction, showing significant variation in temperature sensitivity between months. Warm years were associated with high NDVI and EVI in spring and summer, whereas there was little effect of temperature in autumn and a negative effect in winter. Elevation was shown to mediate phenological change via a magnification of temperature responses on the highest mountains. Together, these predict that climate change will drive substantial changes in mountain summit phenology, especially by advancing spring growth at high elevations. The phenological plasticity underlying these temperature responses may allow long-lived alpine plants to acclimate to warmer temperatures. Conversely, longer growing seasons may facilitate colonization and competitive exclusion by species currently restricted to lower elevations. In either case, these results show previously unreported seasonal and elevational variation in the temperature sensitivity of mountain vegetation activity.
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