Asia-Pacific Remote Sensing最新文献_第7页

Improvements in the on-orbit calibration of the Terra MODIS short-wave infrared spectral bands Terra MODIS短波红外波段在轨定标的改进

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2326517

X. Xiong, A. Angal, Yonghong Li

{"title":"Improvements in the on-orbit calibration of the Terra MODIS short-wave infrared spectral bands","authors":"X. Xiong, A. Angal, Yonghong Li","doi":"10.1117/12.2326517","DOIUrl":"https://doi.org/10.1117/12.2326517","url":null,"abstract":"The short-wave infrared (SWIR) bands (5-7, 26) of Terra MODIS, co-located with the mid-wave infrared (MWIR) bands (20-25) on the short and mid-wave infrared (SMIR) Focal Plane Assembly (FPA) have a known issue related to 5.3 μm out-of-band (OOB) thermal leak and electronic crosstalk that was identified prelaunch. Intensive efforts were undertaken shortly after launch to mitigate its impacts on the on-orbit calibration and in turn the level 1B (L1B) products. In order to the isolate the OOB contribution among the SWIR bands, special night time day mode (NTDM) operations have been regularly scheduled to collect Earth scene reflective solar bands (RSB) data during spacecraft night time. As MODIS does not have a spectral band centered at 5.3 μm, measurements from the MODIS Airborne Simulator (MAS) spectrometer field campaigns in the early months after Terra launch were used to help identify band 28 (7.325 μm) as the best surrogate to simulate the radiances at 5.3 μm. As a result, band 28 is used as the sending band for the SWIR crosstalk correction for Terra MODIS. In the case of Aqua MODIS, band 25 (4.52 μm) was found to be more effective as the sending band for the SWIR crosstalk correction. In recent years, the Terra MODIS PV LWIR electronic crosstalk (including band 28), has gradually increased, more significantly after the safe-mode event occurred in Feb, 2016. This accentuated degradation in the PV LWIR performance has also impacted the performance of on-orbit SWIR crosstalk correction algorithm and thus the L1B products. In this paper, we examine the use of band 25 as the sending band for Terra MODIS SWIR crosstalk correction and compare its performance with that based on band 28 as the sending band. Results indicate an improvement in the stability of the on-orbit gain for the SWIR bands and a reduced detector-detector and subframe striping in the L1B products, especially during the period when the PV LWIR electronic crosstalk is more severe.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"29 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115031571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Temporal and spatial evaluation of long-term satellite-based precipitation products across the complex topographical and climatic gradients of Chile 智利复杂地形和气候梯度下长期卫星降水产品的时空评价

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2513645

M. Zambrano-Bigiarini

{"title":"Temporal and spatial evaluation of long-term satellite-based precipitation products across the complex topographical and climatic gradients of Chile","authors":"M. Zambrano-Bigiarini","doi":"10.1117/12.2513645","DOIUrl":"https://doi.org/10.1117/12.2513645","url":null,"abstract":"Satellite-based rainfall estimates (SRE) have become a promising data source to overcome some limitations of ground-based rainfall measurements, in particular for hydrological and other environmental applications. This study evaluates the spatial and temporal performance of four long-term SRE products (TMPA 3B42v7, CHIRPSv2, MSWEPv1.1 and MSWEPv2.2) over the complex topography and climatic gradients of Chile. Time series of precipitation measured at 371 stations are compared against the corresponding grid cell of each SRE (in their original spatial resolution) at different temporal scales (daily, monthly, seasonal, annual). The modified Kling-Gupta efficiency along with its three individual components were used to assess the performance of each SRE, while two categorical indices (POD, and fBIAS) were used to evaluate the skill of each SRE to correctly capture different precipitation intensities. Results revealed that all SREs performed best in Central-Southern Chile (32.18-36.4°S), in particular at lowand mid-elevation zones (0-1000 m a.s.l.). Seasonally, all products performed best in terms of KGE0 during the wet autumn and winter seasons (MAM-JJA) compared to summer (DJF). In addition, all SREs were able to correctly identify no rain events, but during rainy days all SREs that did not use a local dataset of precipitation to recalibrate their estimates presented a low skill in providing an accurate classification of different precipitation intensities. Overall, MSWPEPv22 showed the best performance at all time scales and country-wide, due to the use of a Chilean dataset of daily data for calibrating its precipitation estimates, making it a good candidate for hydrological applications in Chile. Finally, we conclude that when the in situ precipitation dataset used in the evaluation of different SREs does not cover the headwaters of the catchments, the obtained performances should only be considered as first guess about how well a given SRE represent the real amount of water in an area.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122987230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Initial radiometric calibration status and performance of NOAA-20 VIIRS reflective solar bands NOAA-20 VIIRS反射太阳波段的初始辐射定标状态和性能

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2324523

N. Lei, K. Twedt, Xuexia Chen, X. Xiong

{"title":"Initial radiometric calibration status and performance of NOAA-20 VIIRS reflective solar bands","authors":"N. Lei, K. Twedt, Xuexia Chen, X. Xiong","doi":"10.1117/12.2324523","DOIUrl":"https://doi.org/10.1117/12.2324523","url":null,"abstract":"The Earth-observing Visible Infrared Imaging Radiometer Suite (VIIRS) on the NOAA-20 satellite (formerly the Joint Polar Satellite System-1) is the follow-on sensor to the early launched VIIRS on the Suomi National Polar-orbiting Partnership (SNPP) satellite. The on-orbit radiometric calibration of its reflective solar bands (RSBs) is regularly performed primarily through observations of an onboard sunlit solar diffuser (SD). The on-orbit change of the SD bidirectional reflectance distribution function (BRDF) value, denoted as the H-factor, is determined by an onboard solar diffuser stability monitor (SDSM). The scene spectral radiance is calculated by a quadratic polynomial of the background subtracted detector digital number for most of the RSBs and a cubic polynomial for the M8-11 bands. A numerical factor, denoted as the F-factor, provides an on-orbit adjustment to the prelaunch polynomial coefficients through observations of the sunlit SD. The accuracy and change in the F-factor directly affect the sensor radiometric performance. The accuracy of the F-factor is proportionally affected by the accuracy in the H-factor. In this paper, we show the time trends of the Hand F-factors and the SDSM detector gain, and also compare the trends with those for the previous VIIRS instrument on the Suomi National Polar-orbiting Partnership satellite. We derive the Earth view signal-to-noise ratio at the typical spectral radiance level and estimate the calibration bias between the two VIIRS instruments through observations of the Moon and pseudo-invariant Earth sites.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130223385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Advanced technology land imaging spectroradiometer: a next generation sustainable land imager 先进技术土地成像光谱辐射计:下一代可持续土地成像仪

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2501986

J. Puschell, J. Schlaerth

引用次数: 0

Association between upper level diffluence in the Tropical Easterly Jet and the formation of the strongest Atlantic hurricanes in recent years 近年来热带偏东急流高层扩散与最强大西洋飓风形成的关系

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2500287

T. Krishnamurti, N. Karmakar, V. Misra, B. Nag, D. Sahu, S. Dubey, Z. Haddad

引用次数: 1

Quantifying the spatio-temporal variations and impact factors for vegetation coverage in the karst regions of Southwest China using Landsat data and Google Earth engine 基于Landsat数据和Google Earth引擎的西南喀斯特地区植被覆盖度时空变化及影响因素量化研究

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2323687

J. Pei, Z. Niu, Li Wang, N. Huang, Jianhua Cao

{"title":"Quantifying the spatio-temporal variations and impact factors for vegetation coverage in the karst regions of Southwest China using Landsat data and Google Earth engine","authors":"J. Pei, Z. Niu, Li Wang, N. Huang, Jianhua Cao","doi":"10.1117/12.2323687","DOIUrl":"https://doi.org/10.1117/12.2323687","url":null,"abstract":"This study proposed a remote sensing-based approach to quantify the spatio-temporal patterns of vegetation dynamics and associated impact factors in typical karst regions of Southwest China. Google Earth engine (GEE), the world's most advanced geospatial data cloud computing platform, was employed to construct long time series satellite data set with 30 m resolution, composed of nearly 4,000 Landsat scenes from 1988 to 2016. Image preprocessing was also conducted on the GEE platform. The maximum value composite (MVC) method was used to produce annual maximum normalized difference vegetation index (NDVI) of the study areas. Annual maximum fractional vegetation cover (annFVC) was thus quantitatively estimated based on Dimidiate Pixel Model (DPM). Ordinary least squares (OLS) regression was adopted to identify the spatial patterns of the direction and rate of change in annFVC at a pixel scale. In addition, a terrain niche index (TNI) was used to investigate the influence of topographic factors on vegetation trends. Moreover, the relationships between annFVC and climatic factors were identified using correlation analysis. The results show that annFVC significantly increased at a rate of 0.0032/year in Nandong and 0.0041/year in Xiaojiang watershed for the period 1988-2016. Furthermore, 26.97% and 27.16% of pixels were found to undergo significant increase in terms of annFVC in Nandong and Xiaojiang, respectively. For both Nandong and Xiaojiang, decreasing vegetation trend was curbed with the increase of elevation and slope. Additionally, correlation analysis demonstrated that annFVC was more strongly and positively correlated with temperature than with precipitation in spite of insignificance.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131271234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

A low-wavenumber analysis of the environmental and vortex-scale variables responsible for rapid intensity changes in landfalling tropical cyclones 对导致登陆热带气旋快速强度变化的环境和涡旋尺度变量的低波数分析

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2500290

B. Saiprasanth, Z. Haddad, S. Hristova-Veleva, F. Marks

{"title":"A low-wavenumber analysis of the environmental and vortex-scale variables responsible for rapid intensity changes in landfalling tropical cyclones","authors":"B. Saiprasanth, Z. Haddad, S. Hristova-Veleva, F. Marks","doi":"10.1117/12.2500290","DOIUrl":"https://doi.org/10.1117/12.2500290","url":null,"abstract":"Forecasting rapid intensity changes in tropical cyclones (TCs) is hard as the factors responsible span many scales. External and internal dynamical and thermodynamical variables act simultaneously in a nonlinear fashion, either complementing, amplifying, inhibiting or not impacting the TC intensity at all. We try to address the following question: What is the relative importance of the external and vortex-scale variables that influence rapid intensity changes within a TC? Further, which of these variables must be prioritized from an observational standpoint? To answer these questions, a systematic analysis was conducted on a large number of representative TCs to make statistically significant conclusions using discriminant analyses of wavenumber (WN) - filtered fields, with a principal component analysis to detect over-fitting and identify the subset of variables (from the environment and the vortex) consistently correlated with rapid intensity change. Our analyses indicate that a small number of variables wield the most influence on TC rapid intensity changes. The most important variables within the vortex are the WN 0 of precipitation within the radius of maximum winds, the amplitudes of WN 1 of precipitation and the mid-level horizontal moisture flux convergence in the rain band region. Likewise, the most important environmental variables are the angle of the driest air from the shear vector and the magnitude of environmental wind shear. These variables must be prioritized in future observational and consequent data assimilation efforts.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121912853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Fast physical-random number generation for laser range finders using a laser diode's frequency noise: comparison of the used lasers for fast random number generation 使用激光二极管频率噪声的激光测距仪的快速物理随机数生成:用于快速随机数生成的常用激光器的比较

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2324692

Yuki Kasuya, Masamichi Suzuki, K. Matsumoto, H. Arai, Takashi Sato, S. Sakamoto, M. Ohkawa, Y. Ohdaira

{"title":"Fast physical-random number generation for laser range finders using a laser diode's frequency noise: comparison of the used lasers for fast random number generation","authors":"Yuki Kasuya, Masamichi Suzuki, K. Matsumoto, H. Arai, Takashi Sato, S. Sakamoto, M. Ohkawa, Y. Ohdaira","doi":"10.1117/12.2324692","DOIUrl":"https://doi.org/10.1117/12.2324692","url":null,"abstract":"While optical laser range finders use random signals to determine distance, a laser diode’s fast frequency noise can perform the task. Moreover, this signal can be applied to physical-random number generation. This research describes a method, whereby laser diode’s frequency noise characteristics generate a large number of physical-random numbers and determine the distance to a target [1] [2]. We tested the random number generating- and distance- measuring capabilities of two types of lasers; a Fabry-Perot-LD and VCSEL: (Vertical Cavity Surface Emitting Laser). With the Fabry-Perot etalon functioning as frequency discriminator, we investigated the physical-random numbers’ characteristics from both Fabry-Perot-LD’s and the VCSEL’s characteristic’s points of view. We verified the generated binary number’s randomness, using NIST FIPS140-2 test, and noted the Random Number Generation (RNG) speed of a FP-LD was 48 Gbit/s, and that of a VCSEL was 159 Gbit/s. When the generation speed of the physical-random number is high, we can increase the sampling rate of our range finders and improve resolution.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124666707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Deriving the slant visibility using the Klett method and the visualization of the slant visibility at the airport 利用Klett方法推导斜面能见度及机场斜面能见度的可视化

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2327108

Yuzhao Ma, Jiaqi Liu, Xing-long Xiong

{"title":"Deriving the slant visibility using the Klett method and the visualization of the slant visibility at the airport","authors":"Yuzhao Ma, Jiaqi Liu, Xing-long Xiong","doi":"10.1117/12.2327108","DOIUrl":"https://doi.org/10.1117/12.2327108","url":null,"abstract":"Atmosphere visibility is one of the most important meteorological quantities in civil aviation domain. In practice the slant visibility is more important than the horizontal visibility for the pilot. With the help of the known Klett approach, a lidar can be used for determination of atmosphere extinction coefficient profiles. Consequently, the slant visibility can be obtained. However, the boundary value of the atmosphere extinction coefficient and the k factor in the relationship between atmosphere extinction coefficient and the atmosphere backscattering coefficient have to be firstly determined. In the present work we construct the nonlinear equations that the atmosphere extinction coefficient and the k factor must satisfy. As the solutions of the equations the atmosphere extinction coefficient and the k factor are for the first time obtained simultaneously. At the end the atmosphere extinction coefficients and the slant visibilities are obtained. The numerical simulations have been performed using the real lidar data and the aerosol optical depth observed by the installed sun photometer. The flights are demonstrated using the popular flight simulator Prepar3D under different visibilities.","PeriodicalId":370971,"journal":{"name":"Asia-Pacific Remote Sensing","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124793290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mangrove recognition and extraction using multispectral remote sensing data in Beibu Gulf 北部湾红树林多光谱遥感数据识别与提取

Asia-Pacific Remote Sensing Pub Date : 2018-10-23 DOI: 10.1117/12.2324701

Q. Tian, Shanshan Li

引用次数: 1