scholarly journals Influence of Indirect Solar Irradiance on Satellite Observation

2021 ◽  
Author(s):  
Xia Wang ◽  
Zhi LI ◽  
Can Xu ◽  
Yurong Huo ◽  
Yifan Wu
Keyword(s):  
Light Source ◽  
Solar Irradiance ◽  
Satellite Observation ◽  
Optical Characteristics ◽  
Space Domain ◽  
Observation Strategy ◽  
Actual Observation ◽  
Long Time ◽  
Observation Geometry ◽  
Observation Results

Abstract With the development of Space Domain Awareness(SDA), satellites’ optical characteristics are becoming attention-grabbing. Sunlight was usually considered the only light source for the satellites. However, in the actual observation, researchers have found that earthshine and moonlight would increase errors of the observation results, which have greatly influence the estimation of the satellite’s state. In order to avoid this influence, we propose an observation strategy. Firstly, we propose an accurate earthshine model, which considers the earth’s volume and favors long-time continuous satellite observation. Then, we explore the earthshine and moonlight’s impact on satellite observation results and find that this impact varies with the satellite attributes. Furthermore, we Figure out the law of this impact and establish a connection between this law and observation geometry. Finally, a Period Contribution model is proposed to provide a corresponding observation strategy to avoid the influence of earthshine and moonlight.

Autonomous Mission Replanning Method for Imaging Satellites Considering Real-Time Weather Conditions

2016 ◽  
Vol 13 (10) ◽  
pp. 6967-6973 ◽  
Author(s):  
Yongming He ◽  
Lei He ◽  
Yuan Wang ◽  
Yu Xiao ◽  
Yingwu Chen ◽  
...  
Keyword(s):  
Real Time ◽  
Input Data ◽  
Meteorological Factors ◽  
Weather Conditions ◽  
Earth Observation ◽  
Mission Planning ◽  
Satellite Mission ◽  
Actual Observation ◽  
Weather Changes ◽  
Observation Results

During the observations made by imaging satellites, meteorological factors are likely to change frequently. The vagaries of weather conditions and significant effects on the actual observation results mean that there is an urgent need to apply more intelligence to satellite mission planning. Thus, this paper describes an autonomous replanning method for imaging satellites that considers the real-time weather conditions. Considering the characteristics of different input data, this method replans the low-yield task set and fine-tunes others to improve profitability. Moreover, the proposed method can heuristically select the appropriate adjustment rule to achieve autonomous satellite mission planning. A series of simulations with various task quantities and in different environments shows that the proposed method can respond effectively to real-time weather changes, and can steadily improve the total profits in a variety of weather conditions during Earth observation activities.

scholarly journals The CMEMS GlobColour <i>Chlorophyll-a</i> Product Based on Satellite Observation

2019 ◽  
Author(s):  
Philippe Garnesson ◽  
Antoine Mangin ◽  
Odile Fanton d'Andon ◽  
Julien Demaria ◽  
Marine Bretagnon
Keyword(s):  
Satellite Observation ◽  
Global Level ◽  
Marine Strategy Framework Directive ◽  
Spatial Coverage ◽  
Long Time ◽  
Level 3 ◽  
Monitoring Service ◽  
Marine Environmental ◽  
Level 2 ◽  
The Eu

Abstract. This work concerns the chlorophyll products based on Satellite Observation and disseminated in the frame of the Copernicus Marine Environmental Monitoring Service (CMEMS). This work highlights the main advantages provided by the Copernicus Globcolour processor which is used to serve the CMEMS with a long time series from 1997 to present with level 3 &amp; 4 products at Global level (4 km of spatial resolution) and for the Atlantic level 4 product (1 km). It discusses the different ways to merge data coming from different sensors and it is shown that the GlobColour processor approach provide a better flexibility. At present, it is the only one CMEMS processor able to ingest the OLCI-S3A in the merged product (OLCI-S3A data are ingested in the operational CMEMS products since the April 2018 release). Behind the merging, the flagging strategy to go from level 2 provided by spatial agencies to the level 3 CMEMS products is also discussed. A better spatial coverage is demonstrated, including the coastal area which is of particular interest for many users involved in the EU Water Framework and Marine Strategy Framework Directive.

scholarly journals The CMEMS GlobColour chlorophyll <i>a</i> product based on satellite observation: multi-sensor merging and flagging strategies

Ocean Science ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 819-830 ◽  
Author(s):  
Philippe Garnesson ◽  
Antoine Mangin ◽  
Odile Fanton d'Andon ◽  
Julien Demaria ◽  
Marine Bretagnon
Keyword(s):  
Remote Sensing ◽  
Chlorophyll A ◽  
Spatial Resolution ◽  
Remote Sensing Data ◽  
Satellite Observation ◽  
Data Sets ◽  
In Situ Data ◽  
Long Time ◽  
The One ◽  
Monitoring Service

Abstract. This paper concerns the GlobColour-merged chlorophyll a products based on satellite observation (SeaWiFS, MERIS, MODIS, VIIRS and OLCI) and disseminated in the framework of the Copernicus Marine Environmental Monitoring Service (CMEMS). This work highlights the main advantages provided by the Copernicus GlobColour processor which is used to serve CMEMS with a long time series from 1997 to present at the global level (4 km spatial resolution) and for the Atlantic level 4 product (1 km spatial resolution). To compute the merged chlorophyll a product, two major topics are discussed: The first of these topics is the strategy for merging remote-sensing data, for which two options are considered. On the one hand, a merged chlorophyll a product computed from a prior merging of the remote-sensing reflectance of a set of sensors. On the other hand, a merged chlorophyll a product resulting from a combination of chlorophyll a products computed for each sensor. The second topic is the flagging strategy used to discard non-significant observations (e.g. clouds, high glint and so on). These topics are illustrated by comparing the CMEMS GlobColour products provided by ACRI-ST (Garnesson et al., 2019) with the OC-CCI/C3S project (Sathyendranath et al., 2018). While GlobColour merges chlorophyll a products with a specific flagging, the OC-CCI approach is based on a prior reflectance merging before chlorophyll a derivation and uses a more constrained flagging approach. Although this work addresses these two topics, it does not pretend to provide a full comparison of the two data sets, which will require a better characterisation and additional inter-comparison with in situ data.

scholarly journals Nomogram for Predicting Occurrence of Synchronous Liver Metastasis in Colorectal Cancer: A Single-center Retrospective Study Based on Pathological Factors

2021 ◽  
Author(s):  
Yunxiao Liu ◽  
Yuliuming Wang ◽  
Hao Zhang ◽  
Mingyu Zheng ◽  
Chunlin Wang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Liver Metastasis ◽  
Calibration Curve ◽  
Roc Curves ◽  
Logistic Regression Models ◽  
Actual Observation ◽  
N Stage ◽  
Medical University ◽  
Development And Validation ◽  
Observation Results

Abstract PurposeThe purpose of this study was to explore the risk factors for liver metastasis (LM) of colorectal cancer (CRC) and to construct a nomogram for predicting the occurrence of synchronous LM based on baseline and pathological information.MethodsThe baseline and pathological information of 3190 CRC patients from the Department of Colorectal Surgery, the Second Affiliated Hospital of Harbin Medical University between 2012 and 2020 were included. All patients were divided into development and validation cohorts with the 1:1 ratio. Univariate and multivariate logistic regression models were utilized to identify the potential predictors of LM in CRC patients. Using the R tool to create a predictive nomogram. In addition, receiver operating characteristic (ROC) curves was calculated to describe the discriminability of the nomogram. A calibration curve was plotted to compare the predicted and observed results of the nomogram. Decision-making curve analysis (DCA) was used to evaluate the clinical effect of nomogram.ResultsThe nomogram consisted of six features including tumor site, vascular invasion (VI), T stage, N stage, preoperative CEA and CA-199 level. ROC curves for the LM nomogram indicated good discrimination in the development cohort (AUC = 0.885, 95% CI 0.854-0.916) and the validation cohort (AUC = 0.857, 95% CI 0.821-0.893). The calibration curve showed that the prediction results of the nomogram was in good agreement with the actual observation results. Moreover, the DCA curves determined the clinical application value of predictive nomogram.ConclusionsThe pathologic-based nomogram could help clinicians to predict the occurrence of synchronous LM in postoperative CRC patients and provide a reference to perform appropriate metastatic screening plans and rational therapeutic options for the special population.

Observation and Numerical Simulation on Post-Construction Settlement of Dynamically Consolidated Foundation

2011 ◽  
Vol 250-253 ◽  
pp. 1917-1921
Author(s):  
Yong Mou Zhang ◽  
Jian Chang Zhao
Keyword(s):  
Numerical Simulation ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Measurement Data ◽  
Actual Observation ◽  
Consolidation Coefficient ◽  
Simulation Results ◽  
Settlement Behaviour ◽  
Observation Results

The consolidation coefficient, permeability coefficient and other parameters were calculated out based on field measurement data of pore water pressure in this paper. The post-construction settlement behaviour of dynamically consolidated foundation was also simulated. The simulation results were consistent with the actual observation results. The method of this paper provides an effective way for the prediction of post-construction settlement of dynamically consolidated foundation.

Activation of the sol–gel process by visible light-emitting diodes (LEDs) for the synthesis of inorganic films

2015 ◽  
Vol 39 (7) ◽  
pp. 5686-5693 ◽  
Author(s):  
Suqing Shi ◽  
Xavier Allonas ◽  
Céline Croutxé-Barghorn ◽  
Abraham Chemtob
Keyword(s):  
Visible Light ◽  
Light Source ◽  
Hybrid Materials ◽  
Solar Irradiance ◽  
Sol Gel ◽  
Simple Approach ◽  
Light Emitting ◽  
Acid Generation ◽  
Inorganic Films ◽  
Sol Gel Process

Photosensitized acid generation opens the possibility of using a visible LED light source for inorganic photo sol–gel process. It also provides a simple approach for sustainable synthesis of inorganic or hybrid materials under solar irradiance.

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