Effects of Day/Night Factor on the Detection Performance of FY4A Lightning Mapping Imager in Hainan, China
In this study, the effect of day/night factor on the detection performance of the FY4A lightning mapping imager (<i>LMI</i>) is evaluated using the Bayesian theorem, and by comparing it to the measurements made by a ground-based low-frequency magnetic field lightning location system. Bot...
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MDPI AG
2021-06-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/11/2200 |
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| author | Hao Sun Jing Yang Qilin Zhang Lin Song Haiyang Gao Xiaoqin Jing Guo Lin Kang Yang |
| author_facet | Hao Sun Jing Yang Qilin Zhang Lin Song Haiyang Gao Xiaoqin Jing Guo Lin Kang Yang |
| author_sort | Hao Sun |
| collection | DOAJ |
| description | In this study, the effect of day/night factor on the detection performance of the FY4A lightning mapping imager (<i>LMI</i>) is evaluated using the Bayesian theorem, and by comparing it to the measurements made by a ground-based low-frequency magnetic field lightning location system. Both the datasets were collected in the summers of 2019–2020 in Hainan, China. The results show that for the observed summer thunderstorms in Hainan, the daytime detection efficiencies of <i>LMI</i> (<i>DE<sub>LMI</sub></i>) were 20.41~35.53% lower than the nighttime <i>DE<sub>LMI</sub></i>. Compared to other space-based lightning sensors (lightning imaging sensors/optical transient detectors (LIS/OTD) and geostationary lightning mapper (GLM)), the detection performance of <i>LMI</i> is more significantly influenced by the day/night factor. The <i>DE<sub>LMI</sub></i> rapidly dropped within about four hours after sunrise while it increased before sunset. For the storms that formed at night and lasted for an entire day, the <i>DE<sub>LMI</sub></i> remained relatively low during the daytime, even as the thunderstorms intensified. The poor detection performance of <i>LMI</i> during daytime is probably because of the sunlight reflection by clouds and atmosphere, which results in larger background radiative energy density (<i>RED</i>) than that at night. During night, <i>LMI</i> captured the lightning signals well with low <i>RED</i> (8.38~10.63 μJ sr<sup>−1</sup> m<sup>−2</sup> nm<sup>−1</sup>). However, during daytime, signals with <i>RED</i> less than 77.12 μJ sr<sup>−1</sup> m<sup>−2</sup> nm<sup>−1</sup> were filtered, thus lightning groups could rarely be identified by <i>LMI</i>, except those with extremely high <i>RED</i>. Due to the limitations of the Bayesian theorem, the obtained <i>DE</i> in this study was “relative” <i>DE</i> rather than “absolute” <i>DE</i>. To obtain the absolute <i>DE</i> of <i>LMI</i>, the total lightning density is necessary but can hardly be measured. Nonetheless, the results shown here clearly indicate the strong impact of day/night factor on the detection performance of <i>LMI</i>, and can be used to improve the design and post-processing method of <i>LMI</i>. |
| first_indexed | 2024-03-10T10:43:10Z |
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| spelling | doaj.art-a6fa2a8c21d4403d8314efb760bfaa772023-11-21T22:50:42ZengMDPI AGRemote Sensing2072-42922021-06-011311220010.3390/rs13112200Effects of Day/Night Factor on the Detection Performance of FY4A Lightning Mapping Imager in Hainan, ChinaHao Sun0Jing Yang1Qilin Zhang2Lin Song3Haiyang Gao4Xiaoqin Jing5Guo Lin6Kang Yang7Key Laboratory of Meteorological Disaster, Ministry of Education (KLME), Joint International Research Laboratory of Climate and Environment Change (ILCEC), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster (CIC-FEMD), Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing 210044, ChinaKey Laboratory of Meteorological Disaster, Ministry of Education (KLME), Joint International Research Laboratory of Climate and Environment Change (ILCEC), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster (CIC-FEMD), Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing 210044, ChinaKey Laboratory of Meteorological Disaster, Ministry of Education (KLME), Joint International Research Laboratory of Climate and Environment Change (ILCEC), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster (CIC-FEMD), Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing 210044, ChinaQingdao Engineering Technology Research Center for Meteorological Disaster Prevention, Qingdao Meteorological Bureau, Qingdao 266000, ChinaKey Laboratory of Meteorological Disaster, Ministry of Education (KLME), Joint International Research Laboratory of Climate and Environment Change (ILCEC), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster (CIC-FEMD), Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing 210044, ChinaKey Laboratory of Meteorological Disaster, Ministry of Education (KLME), Joint International Research Laboratory of Climate and Environment Change (ILCEC), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster (CIC-FEMD), Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing 210044, ChinaDepartment of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USADepartment of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USAIn this study, the effect of day/night factor on the detection performance of the FY4A lightning mapping imager (<i>LMI</i>) is evaluated using the Bayesian theorem, and by comparing it to the measurements made by a ground-based low-frequency magnetic field lightning location system. Both the datasets were collected in the summers of 2019–2020 in Hainan, China. The results show that for the observed summer thunderstorms in Hainan, the daytime detection efficiencies of <i>LMI</i> (<i>DE<sub>LMI</sub></i>) were 20.41~35.53% lower than the nighttime <i>DE<sub>LMI</sub></i>. Compared to other space-based lightning sensors (lightning imaging sensors/optical transient detectors (LIS/OTD) and geostationary lightning mapper (GLM)), the detection performance of <i>LMI</i> is more significantly influenced by the day/night factor. The <i>DE<sub>LMI</sub></i> rapidly dropped within about four hours after sunrise while it increased before sunset. For the storms that formed at night and lasted for an entire day, the <i>DE<sub>LMI</sub></i> remained relatively low during the daytime, even as the thunderstorms intensified. The poor detection performance of <i>LMI</i> during daytime is probably because of the sunlight reflection by clouds and atmosphere, which results in larger background radiative energy density (<i>RED</i>) than that at night. During night, <i>LMI</i> captured the lightning signals well with low <i>RED</i> (8.38~10.63 μJ sr<sup>−1</sup> m<sup>−2</sup> nm<sup>−1</sup>). However, during daytime, signals with <i>RED</i> less than 77.12 μJ sr<sup>−1</sup> m<sup>−2</sup> nm<sup>−1</sup> were filtered, thus lightning groups could rarely be identified by <i>LMI</i>, except those with extremely high <i>RED</i>. Due to the limitations of the Bayesian theorem, the obtained <i>DE</i> in this study was “relative” <i>DE</i> rather than “absolute” <i>DE</i>. To obtain the absolute <i>DE</i> of <i>LMI</i>, the total lightning density is necessary but can hardly be measured. Nonetheless, the results shown here clearly indicate the strong impact of day/night factor on the detection performance of <i>LMI</i>, and can be used to improve the design and post-processing method of <i>LMI</i>.https://www.mdpi.com/2072-4292/13/11/2200FY4A lightning mapping imagerlow-frequency magnetic field lightning location systemdetection efficiencyBayesian theoremday/night factors |
| spellingShingle | Hao Sun Jing Yang Qilin Zhang Lin Song Haiyang Gao Xiaoqin Jing Guo Lin Kang Yang Effects of Day/Night Factor on the Detection Performance of FY4A Lightning Mapping Imager in Hainan, China Remote Sensing FY4A lightning mapping imager low-frequency magnetic field lightning location system detection efficiency Bayesian theorem day/night factors |
| title | Effects of Day/Night Factor on the Detection Performance of FY4A Lightning Mapping Imager in Hainan, China |
| title_full | Effects of Day/Night Factor on the Detection Performance of FY4A Lightning Mapping Imager in Hainan, China |
| title_fullStr | Effects of Day/Night Factor on the Detection Performance of FY4A Lightning Mapping Imager in Hainan, China |
| title_full_unstemmed | Effects of Day/Night Factor on the Detection Performance of FY4A Lightning Mapping Imager in Hainan, China |
| title_short | Effects of Day/Night Factor on the Detection Performance of FY4A Lightning Mapping Imager in Hainan, China |
| title_sort | effects of day night factor on the detection performance of fy4a lightning mapping imager in hainan china |
| topic | FY4A lightning mapping imager low-frequency magnetic field lightning location system detection efficiency Bayesian theorem day/night factors |
| url | https://www.mdpi.com/2072-4292/13/11/2200 |
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