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Articoli di riviste sul tema "Spaceborne lida"

Autore: Grafiati

Pubblicato: 31 agosto 2024

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1

Liu, Qun, Xiaoyu Cui, Cédric Jamet, Xiaolei Zhu, Zhihua Mao, Peng Chen, Jian Bai e Dong Liu. "A Semianalytic Monte Carlo Simulator for Spaceborne Oceanic Lidar: Framework and Preliminary Results". Remote Sensing 12, n. 17 (31 agosto 2020): 2820. http://dx.doi.org/10.3390/rs12172820.

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Spaceborne lidar (light detection and ranging) is a very promising tool for the optical properties of global atmosphere and ocean detection. Although some studies have shown spaceborne lidar’s potential in ocean application, there is no spaceborne lidar specifically designed for ocean studies at present. In order to investigate the detection mechanism of the spaceborne lidar and analyze its detection performance, a spaceborne oceanic lidar simulator is established based on the semianalytic Monte Carlo (MC) method. The basic principle, the main framework, and the preliminary results of the simulator are presented. The whole process of the laser emitting, transmitting, and receiving is executed by the simulator with specific atmosphere–ocean optical properties and lidar system parameters. It is the first spaceborne oceanic lidar simulator for both atmosphere and ocean. The abilities of this simulator to characterize the effect of multiple scattering on the lidar signals of different aerosols, clouds, and seawaters with different scattering phase functions are presented. Some of the results of this simulator are verified by the lidar equation. It is confirmed that the simulator is beneficial to study the principle of spaceborne oceanic lidar and it can help develop a high-precision retrieval algorithm for the inherent optical properties (IOPs) of seawater.

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2

Ji, Jie, Chenbo Xie, Kunming Xing, Bangxin Wang, Jianfeng Chen, Liangliang Cheng e Xu Deng. "Simulation of Compact Spaceborne Lidar with High-Repetition-Rate Laser for Cloud and Aerosol Detection under Different Atmospheric Conditions". Remote Sensing 15, n. 12 (10 giugno 2023): 3046. http://dx.doi.org/10.3390/rs15123046.

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To provide references for the design of the lab’s upcoming prototype of the compact spaceborne lidar with a high-repetition-rate laser (CSLHRL), in this paper, the detection signal of spaceborne lidar was simulated by the measured signal of ground-based lidar, and then, the detection capability of spaceborne lidar under different atmospheric conditions was evaluated by means of the signal-to-noise ratio (SNR), volume depolarization ratio (VDR) and attenuated color ratio (ACR). Firstly, the Fernald method was used to invert the optical parameters of cloud and aerosol with the measured signal of ground-based lidar. Secondly, the effective signal of the spaceborne lidar was simulated according to the known atmospheric optical parameters and the parameters of the spaceborne lidar system. Finally, by changing the cumulative laser pulse number and atmospheric conditions, a simulation was carried out to further evaluate the detection performance of the spaceborne lidar, and some suggestions for the development of the system are given. The experimental results showed that the cloud layer and aerosol layer with an extinction coefficient above 0.3 km−1 could be easily obtained when the laser cumulative pulse number was 1000 and the vertical resolution was 15 m at night; the identification of moderate pollution aerosols and thick clouds could be easily identified in the daytime when the laser cumulative pulse number was 10,000 and the vertical resolution was 120 m.

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Zhang, Zhenhua, Peng Chen e Zhihua Mao. "SOLS: An Open-Source Spaceborne Oceanic Lidar Simulator". Remote Sensing 14, n. 8 (12 aprile 2022): 1849. http://dx.doi.org/10.3390/rs14081849.

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In recent years, oceanic lidar has seen a wide range of oceanic applications, such as optical profiling and detecting bathymetry. Furthermore, spaceborne lidars, CALIOP and ICESat-2, designed for atmospheric and ice science applications, have been used for ocean backscattering retrievals, but, until now, there has been no spaceborne lidar specifically designed for ocean detection. There is a demand for an effective lidar simulator to study the detection potential capability of spaceborne oceanic lidar. In this study, an open-source spaceborne oceanic lidar simulator named SOLS was developed, which is available freely. Moreover, the maximum detectable depth and corresponding optimal wavelength for spaceborne lidar were analyzed at a global scale by using SOLS. The factors controlling detection limits of a spaceborne ocean profiling lidar in different cases were discussed. Then, the maximum detectable depths with different relative measurement errors and the influence of solar background radiance were estimated. Subsequently, the effects of laser and detector parameters on maximum detectable depths were studied. The relationship between the lidar detectable depth and the ocean mixed layer depth was also discussed. Preliminary results show that the maximum detectable depth could reach deeper than 120 m in the oligotrophic sea at low latitudes. We found that 490 nm is the optimal wavelength for most of the open seawater. For coastal water, 532 nm is a more suitable choice considering both the technical maturity and geophysical parameters. If possible, a lidar equipped with 440 nm could achieve the greatest depth in oligotrophic seawater in subtropical gyres north and south of the equator. The upper mixed layer vertical structure in most of the global open ocean is within the lidar maximum detectable depth. These results show that SOLS can help the design of future spaceborne oceanic lidar systems a lot.

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4

Yamamoto, Yasuji, Noritaka Tanioka e Tadashi Imai. "The spaceborne lidar experiment". Acta Astronautica 39, n. 9-12 (novembre 1996): 687–95. http://dx.doi.org/10.1016/s0094-5765(97)00050-7.

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5

Liu Dong, 刘东, 陈斯婕 Chen Sijie, 刘群 Liu Qun, 柯举 Ke Ju, 王南朝 Wang Nanchao, 孙颖姗 Sun Yingshan, 王帅博 Wang Shuaibo et al. "星载环境探测激光雷达及其关键技术". Acta Optica Sinica 42, n. 17 (2022): 1701001. http://dx.doi.org/10.3788/aos202242.1701001.

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6

Liu, Qun, Dong Liu, Jian Bai, Xiaoyu Cui, Yudi Zhou, Peituo Xu, Zhipeng Liu e Xiaobin Wang. "The Nonlinear Effective Attenuation Coefficient of Spaceborne Oceanic Lidar Signal". EPJ Web of Conferences 237 (2020): 08022. http://dx.doi.org/10.1051/epjconf/202023708022.

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Multiple scattering is an inevitable effect in spaceborne oceanic lidar because of the large footprint size and the high optical density of seawater. The effective attenuation coefficient klidar in oceanic lidar equation, which indicates the influence of the multiple scattering effect on the formation of lidar returns, is an important parameter in the retrieval of inherent optical properties (IOPs) of seawater. In this paper, the nonlinearity of klidar and the relationships between klidar and the IOPs of seawater are investigated by solving the radiative transfer equation with an improved semianalytic Monte Carlo model. klidar is found to decrease exponentially with the increase of depth in homogeneous waters. klidar is given as an exponential function of depth and IOPs of seawater. The results in this paper can help to have a better understanding of the multiple scattering effect of spaceborne lidar and improve the retrieval accuracy of the IOPs of seawater using spaceborne lidar.

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7

Wan Yuan, 万渊, 陈菡 Cheng Han, 杜嘉旻 Du Jiamin, 孟洁 Meng Jie, 谢可迪 Xie Kedi, 王明建 Wang Mingjian, 马秀华 Ma Xiuhua, 刘继桥 Liu Jiqiao, 侯霞 Hou Xia e 陈卫标 Chen Weibiao. "星载激光雷达激光器热控技术研究". Chinese Journal of Lasers 50, n. 14 (2023): 1401005. http://dx.doi.org/10.3788/cjl221567.

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8

Chu Jiaqi, 储嘉齐, 韩於利 Han Yuli, 孙东松 Sun Dongsong, 赵一鸣 Zhao Yiming e 刘恒嘉 Liu Hengjia. "星载多普勒测风激光雷达小型化光学接收机". Infrared and Laser Engineering 51, n. 9 (2022): 20210831. http://dx.doi.org/10.3788/irla20210831.

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9

Marenco, Franco, Gemma Halloran e Mary Forsythe. "Operational use of spaceborne lidar datasets". EPJ Web of Conferences 176 (2018): 02009. http://dx.doi.org/10.1051/epjconf/201817602009.

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The Met Office plans to use space lidar datasets from CALIPSO, CATS, Aeolus and EarthCARE operationally in near real time (NRT), for the detection of aerosols. The first step is the development of NRT imagery for nowcasting of volcanic events, air quality, and mineral dust episodes. Model verification and possibly assimilation will be explored. Assimilation trials of Aeolus winds are also planned. Here we will present our first in-house imagery and our operational requirements.

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10

Liao Shujun, 廖淑君, 郜海阳 Gao Haiyang, 寇蕾蕾 Kou Leilei, 康佳慧 Kang Jiahui, 卜令兵 Bu Lingbing e 王震 Wang Zhen. "星载激光雷达探测云与气溶胶的仿真模拟". Laser & Optoelectronics Progress 59, n. 10 (2022): 1028001. http://dx.doi.org/10.3788/lop202259.1028001.

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Zhou Xin, 周鑫, 杨坚 Yang Jian e 李松 Li Song. "星载单光子激光雷达海面回波信号模型". Acta Optica Sinica 41, n. 19 (2021): 1928002. http://dx.doi.org/10.3788/aos202141.1928002.

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12

Song, Rui, Adam Povey e Roy G. Grainger. "Characterization of dust aerosols from ALADIN and CALIOP measurements". Atmospheric Measurement Techniques 17, n. 8 (26 aprile 2024): 2521–38. http://dx.doi.org/10.5194/amt-17-2521-2024.

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Abstract. Atmospheric aerosols have pronounced effects on climate at both regional and global scales, but the magnitude of these effects is subject to considerable uncertainties. A major contributor to these uncertainties is an incomplete understanding of the vertical structure of aerosol, largely due to observational limitations. Spaceborne lidars can directly observe the vertical distribution of aerosols globally and are increasingly used in atmospheric aerosol remote sensing. As the first spaceborne high-spectral-resolution lidar (HSRL), the Atmospheric LAser Doppler INstrument (ALADIN) on board the Aeolus satellite was operational from 2018 to 2023. ALADIN data can be used to estimate aerosol extinction and co-polar backscatter coefficients separately without an assumption of the lidar ratio. This study assesses the performance of ALADIN's aerosol retrieval capabilities by comparing them with Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) measurements. A statistical analysis of retrievals from both instruments during the June 2020 Saharan dust event indicates consistency between the observed backscatter and extinction coefficients. During this extreme dust event, CALIOP-derived aerosol optical depth (AOD) exhibited large discrepancies with Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua measurements. Using collocated ALADIN observations to revise the dust lidar ratio to 63.5 sr, AODs retrieved from CALIOP are increased by 46 %, improving the comparison with MODIS data. The combination of measurements from ALADIN and CALIOP can enhance the tracking of aerosols' vertical transport. This study demonstrates the potential for spaceborne HSRL to retrieve aerosol optical properties. It highlights the benefits of spaceborne HSRL in directly obtaining the lidar ratio, significantly reducing uncertainties in extinction retrievals.

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13

Wang, Shuaibo, Ju Ke, Sijie Chen, Zhuofan Zheng, Chonghui Cheng, Bowen Tong, Jiqiao Liu, Dong Liu e Weibiao Chen. "Performance Evaluation of Spaceborne Integrated Path Differential Absorption Lidar for Carbon Dioxide Detection at 1572 nm". Remote Sensing 12, n. 16 (10 agosto 2020): 2570. http://dx.doi.org/10.3390/rs12162570.

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As one of the most influential greenhouse gases, carbon dioxide (CO2) has a profound impact on the global climate. The spaceborne integrated path differential absorption (IPDA) lidar will be a great sensor to obtain the columnar concentration of CO2 with high precision. This paper analyzes the performance of a spaceborne IPDA lidar, which is part of the Aerosol and Carbon Detection Lidar (ACDL) developed in China. The line-by-bine radiative transfer model was used to calculate the absorption spectra of CO2 and H2O. The laser transmission process was simulated and analyzed. The sources of random and systematic errors of IPDA lidar were quantitatively analyzed. The total systematic errors are 0.589 ppm. Monthly mean global distribution of relative random errors (RREs) was mapped based on the dataset in September 2016. Afterwards, the seasonal variations of the global distribution of RREs were studied. The global distribution of pseudo satellite measurements for a 16-day orbit repeat cycle showed relatively uniform distribution over the land of the northern hemisphere. The results demonstrated that 61.24% of the global RREs were smaller than 0.25%, or about 1 ppm, while 2.76% of the results were larger than 0.75%. The statistics reveal the future performance of the spaceborne IPDA lidar.

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14

Amediek, A., A. Fix, G. Ehret, J. Caron e Y. Durand. "Airborne lidar reflectance measurements at 1.57 μm in support of the A-SCOPE mission for atmospheric CO<sub>2</sub>". Atmospheric Measurement Techniques Discussions 2, n. 3 (24 giugno 2009): 1487–536. http://dx.doi.org/10.5194/amtd-2-1487-2009.

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Abstract. The characteristics of the lidar reflectance of the Earth's surface is an important issue for the IPDA lidar technique (integrated path differential absorption lidar) which is the proposed method for the spaceborne measurement of atmospheric carbon dioxide within the framework of ESA's A-SCOPE project. Both, the absolute reflectance of the ground and its variations have an impact on the measurement sensitivity. The first aspect influences the instrument's signal to noise ratio, the second one can lead to retrieval errors, if the ground reflectance changes are strong on small scales. The investigation of the latter is the main purpose of this study. Airborne measurements of the lidar ground reflectance at 1.57 μm wavelength were performed in Central and Western Europe, including many typical land surface coverages as well as the open sea. The analyses of the data show, that the lidar ground reflectance is highly variable on a wide range of spatial scales. However, by means of the assumption of laser footprints on the order of several tens of meters, as planned for spaceborne systems, and by means of an averaging of the data it was shown, that this specific retrieval error is compatible with the sensitivity requirements of spaceborne CO2 measurements.

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15

Zhang, Xuanye, Miaomiao Zhang, Lingbing Bu, Zengchang Fan e Ahmad Mubarak. "Simulation and Error Analysis of Methane Detection Globally Using Spaceborne IPDA Lidar". Remote Sensing 15, n. 13 (23 giugno 2023): 3239. http://dx.doi.org/10.3390/rs15133239.

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Methane (CH4) is recognized as the second most important greenhouse gas. An accurate and precise monitoring of methane gas globally has a vital role in studying the carbon cycle and global warming. The spaceborne integrated path differential absorption (IPDA) lidar is one of the most effective payload for methane detection. The simulation and optimization of the lidar system parameters can create an important base for the development of spaceborne payloads. However, previous IPDA lidar simulations have mostly used standard atmospheric models at simulation conditions, and to the best of our knowledge, there is no literature yet which applies a wavelength optimization to the IPDA system. In this study, we have investigated the relationship between the IPDA lidar system, based on wavelength optimization, and error measurement for CH4 column-averaged concentration. By selecting the wavelengths with the lowest comprehensive error as on-line and off-line, the error has been minimized by 10 ppb approximately relative to before optimization. We have proposed an IPDA simulation model at real atmospheric conditions, combining with ERA-5 reanalysis data, to simulate methane concentration globally, and present the distribution of errors. Finally, after the optimization of the lidar system parameters, we have ensured that the maximum inversion error for CH4 measurement is less than 10 ppb, to provide a reference for designing spaceborne IPDA lidar systems for high-precision CH4 column-averaged concentration detection.

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16

Berthier, S., P. Chazette, J. Pelon e B. Baum. "Comparison of cloud statistics from spaceborne lidar systems". Atmospheric Chemistry and Physics Discussions 8, n. 2 (12 marzo 2008): 5269–304. http://dx.doi.org/10.5194/acpd-8-5269-2008.

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Abstract. The distribution of clouds in a vertical column is assessed on the global scale through analysis of lidar measurements obtained from three spaceborne lidar systems: LITE (Lidar In-space Technology Experiment, NASA), GLAS (Geoscience Laser Altimeter System, NASA), and CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization). Cloud top height (CTH) is obtained from the LITE profiles based on a simple algorithm that accounts for multilayer cloud structures. The resulting CTH results are compared to those obtained by the operational algorithms of the GLAS and CALIOP instruments. Based on our method, spaceborne lidar data are analyzed to establish statistics on the cloud top height. The resulting columnar results are used to investigate the inter-annual variability in the lidar cloud top heights. Statistical analyses are performed for a range of CTH (high, middle, low) and latitudes (polar, middle latitude and tropical). Probability density functions of CTH are developed. Comparisons of CTH developed from LITE, for 2 weeks of data in 1994, with ISCCP (International Satellite Cloud Climatology Project) cloud products show that the cloud fraction observed from spaceborne lidar is much higher than that from ISCCP. Another key result is that ISCCP products tend to underestimate the CTH of optically thin cirrus clouds. Significant differences are observed between LITE-derived cirrus CTH and both GLAS and CALIOP-derived cirrus CTH. Such a difference is due primarily to the lidar signal ratio that is larger than a factor of approximately 3 for the LITE system. A statistical analysis for a full year of data highlights the influence of both the Inter-Tropical Convergence Zone and polar stratospheric clouds.

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Berthier, S., P. Chazette, J. Pelon e B. Baum. "Comparison of cloud statistics from spaceborne lidar systems". Atmospheric Chemistry and Physics 8, n. 23 (3 dicembre 2008): 6965–77. http://dx.doi.org/10.5194/acp-8-6965-2008.

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Abstract. The distribution of clouds in a vertical column is assessed on the global scale through analysis of lidar measurements obtained from three spaceborne lidar systems: LITE (Lidar In-space Technology Experiment, NASA), GLAS (Geoscience Laser Altimeter System, NASA), and CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization). Cloud top height (CTH) is obtained from the LITE profiles based on a simple algorithm that accounts for multilayer cloud structures. The resulting CTH results are compared to those obtained by the operational algorithms of the GLAS and CALIOP instruments. Based on our method, spaceborne lidar data are analyzed to establish statistics on the cloud top height. The resulting columnar results are used to investigate the inter-annual variability in the lidar cloud top heights. Statistical analyses are performed for a range of CTH (high, middle, low) and latitudes (polar, middle latitude and tropical). Probability density functions of CTH are developed. Comparisons of CTH developed from LITE, for 2 weeks of data in 1994, with ISCCP (International Satellite Cloud Climatology Project) cloud products show that the cloud fraction observed from spaceborne lidar is much higher than that from ISCCP. Another key result is that ISCCP products tend to underestimate the CTH of optically thin cirrus clouds. Significant differences are observed between LITE-derived cirrus CTH and both GLAS and CALIOP-derived cirrus CTH. Such a difference is due primarily to the lidar signal-to-noise ratio that is approximately a factor of 3 larger for the LITE system than for the other lidars. A statistical analysis for a full year of data highlights the influence of both the Inter-Tropical Convergence Zone and polar stratospheric clouds.

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18

Yang, Jian, Yue Ma, Huiying Zheng, Yuanfei Gu, Hui Zhou e Song Li. "Analysis and Correction of Water Forward-Scattering-Induced Bathymetric Bias for Spaceborne Photon-Counting Lidar". Remote Sensing 15, n. 4 (8 febbraio 2023): 931. http://dx.doi.org/10.3390/rs15040931.

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The new spaceborne photon-counting lidar, i.e., ICESat-2, has shown great advantages in obtaining nearshore bathymetry at a global scale. The forward-scattering effect in the water column is one of the main error sources in airborne lidar bathymetry (ALB). However, the magnitude of the bathymetric bias for spaceborne lidars and how can we effectively correct this bias have not been evaluated and are very worthy of investigation. In this study, the forward-scattering effect on spaceborne photon-counting lidar bathymetry is quantitatively modeled and analyzed based on the semi-analytic Monte Carlo simulation method. Meanwhile, an empirical formula for correcting forward-scattering-induced bathymetric bias specific to ICESat-2 is derived. When the water depth exceeds 20 m, this bias cannot be neglected for ICESat-2 even in clear open ocean waters. In two study areas with local in situ measurements (St. Thomas and Hawaii), the bathymetric bias of ICESat-2 in deep waters (>20 m) is corrected from exceeding 50 cm to less than 13 cm using the proposed empirical formula. This study is valuable to evaluate and correct the forward-scattering-induced bias for the existing ICESat-2 and is also fundamental to optimizing the hardware parameters of a possible future photon-counting bathymetric lidar.

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任, 文核. "Atmospheric Aerosol Distribution Based on Spaceborne Lidar". Climate Change Research Letters 13, n. 01 (2024): 35–41. http://dx.doi.org/10.12677/ccrl.2024.131005.

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Dawson, K. W., N. Meskhidze, D. Josset e S. Gassó. "Spaceborne observations of the lidar ratio of marine aerosols". Atmospheric Chemistry and Physics 15, n. 6 (23 marzo 2015): 3241–55. http://dx.doi.org/10.5194/acp-15-3241-2015.

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Abstract. Retrievals of aerosol optical depth (AOD) from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite sensor require the assumption of the extinction-to-backscatter ratio, also known as the lidar ratio. This paper evaluates a new method to calculate the lidar ratio of marine aerosols using two independent sources: the AOD from the Synergized Optical Depth of Aerosols (SODA) project and the integrated attenuated backscatter from CALIOP. With this method, the particulate lidar ratio can be derived for individual CALIOP retrievals in single aerosol layer, cloud-free columns over the ocean. Global analyses are carried out using CALIOP level 2, 5 km marine aerosol layer products and the collocated SODA nighttime data from December 2007 to November 2010. The global mean lidar ratio for marine aerosols was found to be 26 sr, roughly 30% higher than the current value prescribed by the CALIOP standard retrieval algorithm. Data analysis also showed considerable spatiotemporal variability in the calculated lidar ratio over the remote oceans. The calculated marine aerosol lidar ratio is found to vary with the mean ocean surface wind speed (U10). An increase in U10 reduces the mean lidar ratio for marine regions from 32 ± 17 sr (for 0 < U10 < 4 m s−1) to 22 ± 7 sr (for U10 > 15 m s−1). Such changes in the lidar ratio are expected to have a corresponding effect on the marine AOD from CALIOP. The outcomes of this study are relevant for future improvements of the SODA and CALIOP operational product and could lead to more accurate retrievals of marine AOD.

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Zhang Chenyang, 张晨阳, 王春辉 Wang Chunhui, 战蓝 Zhan Lan, 齐明 Qi Ming e 蒋硕 Jiang Shuo. "星载微脉冲光子计数激光雷达的探测性能仿真分析". Infrared and Laser Engineering 50, n. 11 (2021): 20200502. http://dx.doi.org/10.3788/irla20200502.

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Zhang Xinyi, 张馨毅, 吴东 Wu Dong, 杨振威 Yang Zhenwei e 贺岩 He Yan. "星载激光雷达数据海面风速反演模型研究". Acta Optica Sinica 42, n. 18 (2022): 1828007. http://dx.doi.org/10.3788/aos202242.1828007.

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Ruan Hang, 阮航, 张强 Zhang Qiang, 杨雨昂 Yang Yu′ang e 徐灿 Xu Can. "非均匀转动空间目标天基逆合成孔径激光雷达成像". Infrared and Laser Engineering 52, n. 2 (2023): 20220406. http://dx.doi.org/10.3788/irla20220406.

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Huang Xing, 黄兴, 胡旭嫣 Hu Xuyan, 刘微微 Liu Weiwei e 赵宏 Zhao Hong. "基于星载激光雷达与多光谱影像结合的土地覆盖分类方法". Chinese Journal of Lasers 51, n. 8 (2024): 0810004. http://dx.doi.org/10.3788/cjl231063.

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Sothe, Camile, Alemu Gonsamo, Ricardo B. Lourenço, Werner A. Kurz e James Snider. "Spatially Continuous Mapping of Forest Canopy Height in Canada by Combining GEDI and ICESat-2 with PALSAR and Sentinel". Remote Sensing 14, n. 20 (15 ottobre 2022): 5158. http://dx.doi.org/10.3390/rs14205158.

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Continuous large-scale mapping of forest canopy height is crucial for estimating and reporting forest carbon content, analyzing forest degradation and restoration, or to model ecosystem variables such as aboveground biomass. Over the last years, the spaceborne Light Detection and Ranging (LiDAR) sensor specifically designed to acquire forest structure information, Global Ecosystem Dynamics Investigation (GEDI), has been used to extract forest canopy height information over large areas. Yet, GEDI has no spatial coverage for most forested areas in Canada and other high latitude regions. On the other hand, the spaceborne LiDAR called Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) provides a global coverage but was not specially developed to study forested ecosystems. Nonetheless, both spaceborne LiDAR sensors obtain point-based information, making spatially continuous forest canopy height estimation very challenging. This study compared the performance of both spaceborne LiDAR, GEDI and ICESat-2, combined with ALOS-2/PALSAR-2 and Sentinel-1 and -2 data to produce continuous canopy height maps in Canada for the year 2020. A set-aside dataset and airborne LiDAR (ALS) from a national LiDAR campaign were used for accuracy assessment. Both maps overestimated canopy height in relation to ALS data, but GEDI had a better performance than ICESat-2 with a mean difference (MD) of 0.9 m and 2.9 m, and a root mean square error (RMSE) of 4.2 m and 5.2 m, respectively. However, as both GEDI and ALS have no coverage in most of the hemi-boreal forests, ICESat-2 captures the tall canopy heights expected for these forests better than GEDI. PALSAR-2 HV polarization was the most important covariate to predict canopy height, showing the great potential of L-band in comparison to C-band from Sentinel-1 or optical data from Sentinel-2. The approach proposed here can be used operationally to produce annual canopy height maps for areas that lack GEDI and ICESat-2 coverage.

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Huang, J. P., Y. Q. Xing e L. Qin. "REVIEW OF NOISE FILTERING ALGORITHM FOR PHOTON DATA". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W10 (7 febbraio 2020): 105–10. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w10-105-2020.

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Abstract. As a continuation of Ice, Cloud, and Land Elevation Satellite-1 (ICESat-1)/Geoscience Laser Altimeter System (GLAS), the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) , which is equipped with the Advanced Topographic Laser Altimeter (ATLAS) system, was successfully launched in 2018. Since ICESat-1/GLAS has facilitated scientific results in the field of forest structure parameter estimation, how to use the ICESat-2/ATLAS photon cloud data to estimate forest structure parameters has become a hotspot in the field of spaceborne photon data application. However, due to the weak photon characteristics of the ICESat-2/ATLAS system, the system is extremely susceptible to noise, which poses a challenge for its subsequent accurate estimation of forest structural parameters. Aiming to filter out the noise photons, the paper introduces the advantages of the spaceborne lidar system ICESat-2/ATLAS than ICESat-1/GLAS. The paper summarizes the research of the simulated photon-counting lidar (PCL) noise filtering algorithm and noise filtering on spaceborne.

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27

Amediek, A., A. Fix, G. Ehret, J. Caron e Y. Durand. "Airborne lidar reflectance measurements at 1.57 μm in support of the A-SCOPE mission for atmospheric CO<sub>2</sub>". Atmospheric Measurement Techniques 2, n. 2 (26 novembre 2009): 755–72. http://dx.doi.org/10.5194/amt-2-755-2009.

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Abstract. The characteristics of the lidar reflectance of the Earth's surface is an important issue for the IPDA lidar technique (integrated path differential absorption lidar) which is the proposed method for the spaceborne measurement of atmospheric carbon dioxide within the framework of ESA's A-SCOPE project. Both, the absolute reflectance of the ground and its variations have an impact on the measurement sensitivity. The first aspect influences the instrument's signal to noise ratio, the second one can lead to retrieval errors, if the ground reflectance changes are strong on small scales. The investigation of the latter is the main purpose of this study. Airborne measurements of the lidar ground reflectance at 1.57 μm wavelength were performed in Central and Western Europe, including many typical land surface coverages as well as the open sea. The analyses of the data show, that the lidar ground reflectance is highly variable on a wide range of spatial scales. However, by means of the assumption of laser footprints in the order of several tens of meters, as planned for spaceborne systems, and by means of an averaging of the data it was shown, that this specific retrieval error is well below 1 ppm (CO2 column mixing ratio), and so compatible with the sensitivity requirements of spaceborne CO2 measurements. Several approaches for upscaling the data in terms of the consideration of larger laser footprints, compared to the one used here, are shown and discussed. Furthermore, the collected data are compared to MODIS ground reflectance data.

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28

Hu Jianbo, 胡建波, 王雄 Wang Xiong, 赵少华 Zhao Shaohua, 王中挺 Wang Zhongting, 杨巨鑫 Yang Juxin, 戴光耀 Dai Guangyao, 谢缘 Xie Yuan et al. "星载高光谱分辨率激光雷达大气气溶胶和云探测研究". Acta Optica Sinica 43, n. 18 (2023): 1899901. http://dx.doi.org/10.3788/aos231437.

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29

Hansen, Johannes N., Steven Hancock, Ludwig Prade, Gerald M. Bonner, Haochang Chen, Ian Davenport, Brynmor E. Jones e Matthew Purslow. "Assessing Novel Lidar Modalities for Maximizing Coverage of a Spaceborne System through the Use of Diode Lasers". Remote Sensing 14, n. 10 (18 maggio 2022): 2426. http://dx.doi.org/10.3390/rs14102426.

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Current satellite lidars have sparse spatial coverage, leading to uncertainty from sampling. This complicates robust change detection and does not allow applications that require continuous coverage. One potential way to increase lidar sampling density is to use more efficient lasers. All current spaceborne lidars use solid-state lasers with a limited efficiency of 5–8%. In this paper, we investigate the potential for using diode lasers, with their higher efficiencies, as an alternative. Diode lasers have reported efficiencies of about 25% and are much smaller and lighter than solid-state lasers. However, they can only emit good beam quality at lower peak powers, which has so far prevented them from being used in spaceborne lidar applications. In this paper, we assess whether the novel lidar modalities necessitated by these lower peak powers are suitable for satellite lidar, determined by whether they can match the design performance of GEDI by being able to accurately measure ground elevation through 98% canopy cover, referred to as having “98% beam sensitivity”. Through this, we show that a diode laser can be operated in pulse train or pulse compressed lidar (PCL) mode from space, using a photon-counting detector. In the best case scenario, this setup requires a detected energy of Edet=0.027 fJ to achieve a beam sensitivity of 98%, which is less than the 0.28 fJ required by a full-waveform solid-state lidar instrument, exemplified by GEDI. When also accounting for the higher laser and detector efficiency, the diode laser in pulse train mode requires similar shot energy as a photon counting solid-state laser such as ICESat-2 which along with the higher laser efficiency could result in a doubling of coverage. We conclude that there is a clear opportunity for diode lasers to be used in spaceborne lidars, potentially allowing wider coverage through their higher efficiencies.

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30

Hongfei Yin, 尹红飞, 郭亮 Liang Guo, 荆丹 Dan Jing, 邢孟道 Mengdao Xing, 曾晓东 Xiaodong Zeng e 胡以华 Yihua Hu. "Parameters analysis of spaceborne synthetic aperture lidar imaging". Infrared and Laser Engineering 50, n. 2 (2021): 20200144. http://dx.doi.org/10.3788/irla20200144.

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31

Hongfei Yin, 尹红飞, 郭亮 Liang Guo, 荆丹 Dan Jing, 邢孟道 Mengdao Xing, 曾晓东 Xiaodong Zeng e 胡以华 Yihua Hu. "Parameters analysis of spaceborne synthetic aperture lidar imaging". Infrared and Laser Engineering 50, n. 2 (2021): 20200144. http://dx.doi.org/10.3788/irla.11_2020-0144.

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32

Hostetler, Chris A., Michael J. Behrenfeld, Yongxiang Hu, Johnathan W. Hair e Jennifer A. Schulien. "Spaceborne Lidar in the Study of Marine Systems". Annual Review of Marine Science 10, n. 1 (3 gennaio 2018): 121–47. http://dx.doi.org/10.1146/annurev-marine-121916-063335.

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33

Wang, Tianyu, Delu Pan, Xianqiang He e Difeng Wang. "Wind vector retrieval algorithm from spaceborne lidar data". Acta Oceanologica Sinica 33, n. 3 (marzo 2014): 129–35. http://dx.doi.org/10.1007/s13131-014-0448-z.

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34

Lu, Xiaomei, Yongxiang Hu, Charles Trepte, Shan Zeng e James H. Churnside. "Ocean subsurface studies with the CALIPSO spaceborne lidar". Journal of Geophysical Research: Oceans 119, n. 7 (luglio 2014): 4305–17. http://dx.doi.org/10.1002/2014jc009970.

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35

Kiemle, C., S. R. Kawa, M. Quatrevalet e E. V. Browell. "Performance simulations for a spaceborne methane lidar mission". Journal of Geophysical Research: Atmospheres 119, n. 7 (9 aprile 2014): 4365–79. http://dx.doi.org/10.1002/2013jd021253.

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36

Escribano, Jerónimo, Enza Di Tomaso, Oriol Jorba, Martina Klose, Maria Gonçalves Ageitos, Francesca Macchia, Vassilis Amiridis et al. "Assimilating spaceborne lidar dust extinction can improve dust forecasts". Atmospheric Chemistry and Physics 22, n. 1 (14 gennaio 2022): 535–60. http://dx.doi.org/10.5194/acp-22-535-2022.

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Abstract. Atmospheric mineral dust has a rich tri-dimensional spatial and temporal structure that is poorly constrained in forecasts and analyses when only column-integrated aerosol optical depth (AOD) is assimilated. At present, this is the case of most operational global aerosol assimilation products. Aerosol vertical distributions obtained from spaceborne lidars can be assimilated in aerosol models, but questions about the extent of their benefit upon analyses and forecasts along with their consistency with AOD assimilation remain unresolved. Our study thoroughly explores the added value of assimilating spaceborne vertical dust profiles, with and without the joint assimilation of dust optical depth (DOD). We also discuss the consistency in the assimilation of both sources of information and analyse the role of the smaller footprint of the spaceborne lidar profiles in the results. To that end, we have performed data assimilation experiments using dedicated dust observations for a period of 2 months over northern Africa, the Middle East, and Europe. We assimilate DOD derived from the Visible Infrared Imaging Radiometer Suite (VIIRS) on board Suomi National Polar-Orbiting Partnership (SUOMI-NPP) Deep Blue and for the first time Cloud-Aerosol Lidar with Orthogonal Polarisation (CALIOP)-based LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies (LIVAS) pure-dust extinction coefficient profiles on an aerosol model. The evaluation is performed against independent ground-based DOD derived from AErosol RObotic NETwork (AERONET) Sun photometers and ground-based lidar dust extinction profiles from the Cyprus Clouds Aerosol and Rain Experiment (CyCARE) and PREparatory: does dust TriboElectrification affect our ClimaTe (Pre-TECT) field campaigns. Jointly assimilating LIVAS and Deep Blue data reduces the root mean square error (RMSE) in the DOD by 39 % and in the dust extinction coefficient by 65 % compared to a control simulation that excludes assimilation. We show that the assimilation of dust extinction coefficient profiles provides a strong added value to the analyses and forecasts. When only Deep Blue data are assimilated, the RMSE in the DOD is reduced further, by 42 %. However, when only LIVAS data are assimilated, the RMSE in the dust extinction coefficient decreases by 72 %, the largest improvement across experiments. We also show that the assimilation of dust extinction profiles yields better skill scores than the assimilation of DOD under an equivalent sensor footprint. Our results demonstrate the strong potential of future lidar space missions to improve desert dust forecasts, particularly if they foresee a depolarization lidar channel to allow discrimination of desert dust from other aerosol types.

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37

Studinger, Michael, Serdar S. Manizade, Matthew A. Linkswiler e James K. Yungel. "High-resolution imaging of supraglacial hydrological features on the Greenland Ice Sheet with NASA's Airborne Topographic Mapper (ATM) instrument suite". Cryosphere 16, n. 9 (9 settembre 2022): 3649–68. http://dx.doi.org/10.5194/tc-16-3649-2022.

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Abstract. Seasonal meltwater pools on the surface of the Greenland Ice Sheet (GrIS) during late spring and summer in lakes on the surface and transforms the ice sheet's surface into a wet environment in the ablation zone below the equilibrium line. These supraglacial lakes in topographic lows on the ice surface are connected by a dendritic pattern of meandering streams and channels that together form a hydrological system consisting of supra-, en-, and subglacial components. Here, we use lidar data from NASA's Airborne Topographic Mapper (ATM) instrument suite and high-resolution optical imagery collected as part of Operation IceBridge (OIB) in spring 2019 over the GrIS to develop methods for the study of supraglacial hydrological features. While airborne surveys have a limited temporal and spatial coverage compared to imaging spaceborne sensors, their high footprint density and high-resolution imagery reveal a level of detail that is currently not obtainable from spaceborne measurements. The accuracy and resolution of airborne measurements complement spaceborne measurements, can support calibration and validation of spaceborne methods, and provide information necessary for high-resolution process studies of the supraglacial hydrological system on the GrIS that currently cannot be achieved from spaceborne observations alone.

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38

Zhang, Chuanliang, Xuejin Sun, Wen Lu, Yingni Shi, Naiying Dou e Shaohui Li. "Relationship between wind observation accuracy and the ascending node of the sun-synchronous orbit for the Aeolus-type spaceborne Doppler wind lidar". Atmospheric Measurement Techniques 14, n. 7 (7 luglio 2021): 4787–803. http://dx.doi.org/10.5194/amt-14-4787-2021.

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Abstract. The launch and operation of the first spaceborne Doppler wind lidar (DWL), Aeolus, is of great significance for observing the global wind field. Aeolus operates on a sun-synchronous dawn–dusk orbit to minimize the negative impact of solar background radiation (SBR) on wind observation accuracy. Future spaceborne DWLs may not operate on sun-synchronous dawn–dusk orbits due to their observational purposes. The impact of the local time of ascending node (LTAN) crossing of sun-synchronous orbits on the wind observation accuracy was studied in this paper by proposing two given Aeolus-type spaceborne DWLs operating on the sun-synchronous orbits with LTANs of 15:00 and 12:00 LT. On these two new orbits, the increments of the averaged SBR received by the new spaceborne DWLs range from 39 to 56 mW m−2 sr−1 nm−1 under cloud-free skies near the summer and winter solstices, which will lead to uncertainties of 0.19 and 0.27 m s−1 in the increment of the averaged Rayleigh channel wind observations for 15:00 and 12:00 LT orbits using the instrument parameters of Aeolus with 30 measurements per observation and 20 laser pulses per measurement. This demonstrates that Aeolus operating on the sun-synchronous dawn–dusk orbit is the optimal observation scenario, and the random error caused by the SBR will be larger on other sun-synchronous orbits. Increasing the laser pulse energy of the new spaceborne DWLs is used to lower the wind observation uncertainties, and a method to quantitatively design the laser pulse energy according to the specific accuracy requirements is proposed in this study based on the relationship between the signal-to-noise ratio and the uncertainty of the response function of the Rayleigh channel. The laser pulse energies of the two new spaceborne DWLs should be set to 70 mJ based on the statistical results obtained using the method. The other instrument parameters should be the same as those of Aeolus. Based on the proposed parameters, the accuracies of about 77.19 % and 74.71 % of the bins of the two new spaceborne DWLs would meet the accuracy requirements of the European Space Agency (ESA) for Aeolus. These values are very close to the 76.46 % accuracy of an Aeolus-type spaceborne DWL when it is free of the impact of the SBR. Moreover, the averaged uncertainties of the two new spaceborne DWLs are 2.62 and 2.69 m s−1, which perform better than that of Aeolus (2.77 m s−1).

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39

Noel, V., H. Chepfer, C. Hoareau, M. Reverdy e G. Cesana. "Effects of solar activity on noise in CALIOP profiles above the South Atlantic Anomaly". Atmospheric Measurement Techniques 7, n. 6 (5 giugno 2014): 1597–603. http://dx.doi.org/10.5194/amt-7-1597-2014.

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Abstract. We show that nighttime dark noise measurements from the spaceborne lidar CALIOP contain valuable information about the evolution of upwelling high-energy radiation levels. Above the South Atlantic Anomaly (SAA), CALIOP dark noise levels fluctuate by ±6% between 2006 and 2013, and follow the known anticorrelation of local particle flux with the 11-year cycle of solar activity (with a 1-year lag). By analyzing the geographic distribution of noisy profiles, we are able to reproduce known findings about the SAA region. Over the considered period, it shifts westward by 0.3° year−1, and changes in size by 6° meridionally and 2° zonally, becoming larger with weaker solar activity. All results are in strong agreement with previous works. We predict SAA noise levels will increase anew after 2014, and will affect future spaceborne lidar missions most near 2020.

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40

Tesche, M., N. Rastak, R. J. Charlson, P. Glantz, P. Zieger e H. C. Hansson. "Reconciling aerosol light extinction measurements from spaceborne lidar observations and in-situ measurements in the Arctic". Atmospheric Chemistry and Physics Discussions 14, n. 5 (4 marzo 2014): 5687–720. http://dx.doi.org/10.5194/acpd-14-5687-2014.

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Abstract (sommario):

Abstract. In this study we investigate to what degree it is possible to reconcile continuously recorded particle light extinction coefficients derived from dry in-situ measurements at Zeppelin station (78.92° N, 11.85° E, 475 m a.s.l.) at Ny-Ålesund, Svalbard, that are recalculated to ambient relative humidity, and simultaneous ambient observations with the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. To our knowledge, this represents the first study that compares spaceborne lidar measurements to optical aerosol properties from short-term in-situ observations (averaged over 5 h) on a case-by-case basis. Finding suitable comparison cases requires an elaborate screening and matching of the CALIOP data with respect to the location of the Zeppelin station as well as in the selection of temporal and spatial averaging intervals for both the ground-based and spaceborne observations. Trustworthy reconciliation of these data cannot be achieved with the closest approach method that is often used in matching CALIOP observations to those taken at ground sites due to the transport pathways of the air parcels that were sampled. The use of trajectories allowed us to establish a connection between spaceborne and ground-based observations for 57 individual overpasses out of a total of 2018 that occurred in our region of interest around Svalbard (0 to 25° E; 75 to 82° N) in the considered year of 2008. Matches could only be established during winter and spring, since the low aerosol load during summer in connection with the strong solar background and the high occurrence rate of clouds strongly influences the performance and reliability of CALIOP observations. Extinction coefficients in the range from 1 to 100 Mm−1 were found for successful matches with an agreement of a factor of 1.85 (median value for a range from 0.38 to 17.9) between the findings of in-situ and spaceborne observations (the latter being generally larger than the former). The remaining difference is likely to be due to the natural variability in aerosol concentration and ambient relative humidity, an insufficient representation of aerosol particle growth in the used hygroscopicity model, or a misclassification of aerosol type (i.e., choice of lidar ratio) in the CALIPSO retrieval.

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41

Tesche, M., P. Zieger, N. Rastak, R. J. Charlson, P. Glantz, P. Tunved e H. C. Hansson. "Reconciling aerosol light extinction measurements from spaceborne lidar observations and in situ measurements in the Arctic". Atmospheric Chemistry and Physics 14, n. 15 (8 agosto 2014): 7869–82. http://dx.doi.org/10.5194/acp-14-7869-2014.

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Abstract (sommario):

Abstract. In this study we investigate to what degree it is possible to reconcile continuously recorded particle light extinction coefficients derived from dry in situ measurements at Zeppelin station (78.92° N, 11.85° E; 475 m above sea level), Ny-Ålesund, Svalbard, that are recalculated to ambient relative humidity, as well as simultaneous ambient observations with the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. To our knowledge, this represents the first study that compares spaceborne lidar measurements to optical aerosol properties from short-term in situ observations (averaged over 5 h) on a case-by-case basis. Finding suitable comparison cases requires an elaborate screening and matching of the CALIOP data with respect to the location of Zeppelin station as well as the selection of temporal and spatial averaging intervals for both the ground-based and spaceborne observations. Reliable reconciliation of these data cannot be achieved with the closest-approach method, which is often used in matching CALIOP observations to those taken at ground sites. This is due to the transport pathways of the air parcels that were sampled. The use of trajectories allowed us to establish a connection between spaceborne and ground-based observations for 57 individual overpasses out of a total of 2018 that occurred in our region of interest around Svalbard (0 to 25° E, 75 to 82° N) in the considered year of 2008. Matches could only be established during winter and spring, since the low aerosol load during summer in connection with the strong solar background and the high occurrence rate of clouds strongly influences the performance and reliability of CALIOP observations. Extinction coefficients in the range of 2 to 130 Mm−1 at 532 nm were found for successful matches with a difference of a factor of 1.47 (median value for a range from 0.26 to 11.2) between the findings of in situ and spaceborne observations (the latter being generally larger than the former). The remaining difference is likely to be due to the natural variability in aerosol concentration and ambient relative humidity, an insufficient representation of aerosol particle growth, or a misclassification of aerosol type (i.e., choice of lidar ratio) in the CALIPSO retrieval.

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42

Dawson, K. W., N. Meskhidze, D. Josset e S. Gassó. "A new study of sea spray optical properties from multi-sensor spaceborne observations". Atmospheric Chemistry and Physics Discussions 14, n. 1 (6 gennaio 2014): 213–44. http://dx.doi.org/10.5194/acpd-14-213-2014.

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Abstract (sommario):

Abstract. Retrievals of aerosol optical depth (AOD) from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite sensor require the assumption of an extinction-to-backscatter ratio, also known as the lidar ratio. This paper evaluates a new method to calculate the lidar ratio of sea spray aerosol using two independent sources: the AOD from the Synergized Optical Depth of Aerosols (SODA) algorithm and the integrated attenuated backscatter from CALIOP. With this method, the particulate lidar ratio can be derived for individual CALIOP retrievals in single aerosol layer columns over the ocean. Global analyses are carried out using CALIOP level 2, 5 km sea spray aerosol layer products and the collocated SODA nighttime data from December 2007 to December 2009. The global mean lidar ratio for sea spray aerosols was found to be 26 sr, roughly 30% higher than the current value prescribed by CALIOP standard retrieval algorithm. Data analysis also showed considerable spatiotemporal variability in the calculated lidar ratio over the remote oceans. The calculated aerosol lidar ratios are shown to be inversely related to the mean ocean surface wind speed: increase in ocean surface wind speed (U10) from 0 to >15 m s−1 reduces the mean lidar ratios for sea spray particles from 32 sr (for 015 m s−1). Such changes in the lidar ratio are expected to have a corresponding effect on the sea spray AOD. The outcomes of this study are relevant for future improvements of the SODA and CALIOP operational product and could lead to more accurate retrievals of sea spray AOD.

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43

Xu, Xiangpeng, Sheng Zhuge, Banglei Guan, Bin Lin, Shuwei Gan, Xia Yang e Xiaohu Zhang. "On-Orbit Calibration for Spaceborne Line Array Camera and LiDAR". Remote Sensing 14, n. 12 (20 giugno 2022): 2949. http://dx.doi.org/10.3390/rs14122949.

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For a multi-mode Earth observation satellite carrying a line array camera and a multi-beam line array LiDAR, the relative installation attitude of the two sensors is of great significance. In this paper, we propose an on-orbit calibration method for the relative installation attitude of the camera and the LiDAR with no need for the calibration field and additional satellite attitude maneuvers. Firstly, the on-orbit joint calibration model of the relative installation attitude of the two sensors is established. However, there may exist a multi-solution problem in the solving of the above model constrained by non-ground control points. Thus, an alternate iterative method by solving the pseudo-absolute attitude matrix of each sensor in turn is proposed. The numerical validation and simulation experiments results show that the relative positioning error of the line array camera and the LiDAR in the horizontal direction of the ground can be limited to 0.8 m after correction by the method in this paper.

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44

Ackermann, Jörg. "Quantitative Assessment of the Sampling Properties of a Spaceborne Lidar (ATLID)". Journal of Applied Meteorology 34, n. 7 (1 luglio 1995): 1559–69. http://dx.doi.org/10.1175/1520-0450-34.7.1559.

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Abstract The European Space Agency plans to install the backscatter lidar system ATLID (atmospheric lidar) on a polar-orbiting platform at the beginning of the next century. This kind of active remote sensing will provide highly accurate information about cloud-top height, which, in addition to collocated passive sounder's measurements of brightness temperature, might improve retrieved vertical temperature profiles and serve as a supplementation of present cloud climatologies. Due to technical constraints, ATLID will not provide spatially continuous information about cloud-top height. The representativeness of the lidar measurements for the whole cloud field constitutes the sampling problem and is investigated in two steps: first, a scan mode for ATLID is developed, which on the assumption that the cloud field is a two-dimensional random variable gives an equal pixel spacing along and across the flight track of the orbiter. Second, the simulated lidar measurements given by the elaborated scan mode are contributed to a spatially continuous cloud field represented by Advanced Very High Resolution Radiometer images. From the dispersed lidar measurements with a footprint diameter of about 1 km the cloud field is restored by a spatial interpolation scheme and compared with the original cloud field by a linear regression analysis. It turns out that the sampling error and hence the benefits of ATLID strongly depend on the meteorological situation: if the required vertical accuracy of the lidar measurement is about 250 m corresponding approximately to half of the vertical resolution of present retrieval schemes, the probability for a meaningful ATLID information is between 40% and 70%. Since an imager cannot provide a useful brightness temperature in case of multilayered or broken clouds within one imager pixel, the synergism of ATLID with a passive instrument also depends on the homogeneity of cloud-top height within the range of 1 km. To cheek this small-scale variability of cloud tops data from the European Lidar Airborne Campaign 1990 are evaluated. Results show that for optically thick clouds the variability exceeds in 3% to 38% of all considered cases a threshold of 250 m. Additionally, power-spectrum analyses confirm the result of the sampling analyses.

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45

Tikhomirov, A. A. "Comparative parameters of airborne and spaceborne lidar monitoring technologies". Kosmìčna nauka ì tehnologìâ 8, n. 1 (30 gennaio 2002): 23–31. http://dx.doi.org/10.15407/knit2002.01.023.

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46

Yaya, Zhang, Xu Mingming, Liu Dong, Bo Guangyu, Shen Wei e Chen Jiexiang. "Thermal analysis and parameter optimization of spaceborne lidar filter". Journal of Applied Optics 38, n. 4 (2017): 633–38. http://dx.doi.org/10.5768/jao201738.0407001.

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47

Reagan, J. A., X. Wang e M. T. Osborn. "Spaceborne lidar calibration from cirrus and molecular backscatter returns". IEEE Transactions on Geoscience and Remote Sensing 40, n. 10 (gennaio 2002): 2285–90. http://dx.doi.org/10.1109/tgrs.2002.802464.

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48

Mu Yongji, 穆永吉, 李蕊 Li Rui, 万渊 Wan Yuan, 刘继桥 Liu Jiqiao, 侯霞 Hou Xia e 陈卫标 Chen Weibiao. "Stray Light Analysis and Suppression for Spaceborne Lidar System". Chinese Journal of Lasers 45, n. 5 (2018): 0510005. http://dx.doi.org/10.3788/cjl201845.0510005.

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49

Reagan, John A. "Spaceborne lidar remote sensing techniques aided by surface returns". Optical Engineering 30, n. 1 (1991): 96. http://dx.doi.org/10.1117/12.55776.

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50

Nava, Enzo, e Emanuele Stucchi. "Development of lasers for spaceborne Doppler wind lidar applications". Optics and Lasers in Engineering 39, n. 2 (febbraio 2003): 255–63. http://dx.doi.org/10.1016/s0143-8166(01)00101-4.

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