GPS-Derived Slant Water Vapor for Cloud Monitoring in Singapore
This paper presents a GPS-derived slant water vapor technique for cloud monitoring in Singapore. The normalized slant wet delay (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/14/21/5459 |
| _version_ | 1797466575476883456 |
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| author | Ding Yu Heh Yee Hui Lee Anik Naha Biswas Liang Mong Koh |
| author_facet | Ding Yu Heh Yee Hui Lee Anik Naha Biswas Liang Mong Koh |
| author_sort | Ding Yu Heh |
| collection | DOAJ |
| description | This paper presents a GPS-derived slant water vapor technique for cloud monitoring in Singapore. The normalized slant wet delay (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>D</mi></mrow></semantics></math></inline-formula>) and slant water vapor (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula>) are introduced. The suitability of the normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> over <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> for cloud monitoring is demonstrated, as it is not very sensitive to the satellite elevation angle. For better illustration and representation of the spatial distribution of the normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula>, the skyplot is discretized into different cells based on the azimuth and elevation angles to produce the spatial plot. The spatial plots are analyzed for cloud monitoring and compared alongside the sky images. The results show that the spatial plots of normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> are generally consistent with the cloud formation observed in the sky images, hence demonstrating their usefulness for cloud monitoring. The probability distribution of the normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> associated with cloudy and clear sky conditions is also analyzed, which shows that the mean values of normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> associated with the former are higher. Finally, the time series of the normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> is explored in relation to the solar irradiance. It is shown that the time series and spatial plots of normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> are also consistent with the ratio of clear sky to measured irradiance. |
| first_indexed | 2024-03-09T18:41:44Z |
| format | Article |
| id | doaj.art-115682e3e6c5469ebff48c62e0cbc0b8 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-09T18:41:44Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-115682e3e6c5469ebff48c62e0cbc0b82023-11-24T06:39:22ZengMDPI AGRemote Sensing2072-42922022-10-011421545910.3390/rs14215459GPS-Derived Slant Water Vapor for Cloud Monitoring in SingaporeDing Yu Heh0Yee Hui Lee1Anik Naha Biswas2Liang Mong Koh3School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, SingaporeSchool of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, SingaporeSchool of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, SingaporeEnergy Research Institute@NTU, Singapore 637553, SingaporeThis paper presents a GPS-derived slant water vapor technique for cloud monitoring in Singapore. The normalized slant wet delay (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>D</mi></mrow></semantics></math></inline-formula>) and slant water vapor (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula>) are introduced. The suitability of the normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> over <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> for cloud monitoring is demonstrated, as it is not very sensitive to the satellite elevation angle. For better illustration and representation of the spatial distribution of the normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula>, the skyplot is discretized into different cells based on the azimuth and elevation angles to produce the spatial plot. The spatial plots are analyzed for cloud monitoring and compared alongside the sky images. The results show that the spatial plots of normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> are generally consistent with the cloud formation observed in the sky images, hence demonstrating their usefulness for cloud monitoring. The probability distribution of the normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> associated with cloudy and clear sky conditions is also analyzed, which shows that the mean values of normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> associated with the former are higher. Finally, the time series of the normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> is explored in relation to the solar irradiance. It is shown that the time series and spatial plots of normalized <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>W</mi><mi>V</mi></mrow></semantics></math></inline-formula> are also consistent with the ratio of clear sky to measured irradiance.https://www.mdpi.com/2072-4292/14/21/5459global positioning system (GPS)slant water vapor (<i>SWV</i>)slant wet delay (<i>SWD</i>)cloud monitoringwhole sky imager |
| spellingShingle | Ding Yu Heh Yee Hui Lee Anik Naha Biswas Liang Mong Koh GPS-Derived Slant Water Vapor for Cloud Monitoring in Singapore Remote Sensing global positioning system (GPS) slant water vapor (<i>SWV</i>) slant wet delay (<i>SWD</i>) cloud monitoring whole sky imager |
| title | GPS-Derived Slant Water Vapor for Cloud Monitoring in Singapore |
| title_full | GPS-Derived Slant Water Vapor for Cloud Monitoring in Singapore |
| title_fullStr | GPS-Derived Slant Water Vapor for Cloud Monitoring in Singapore |
| title_full_unstemmed | GPS-Derived Slant Water Vapor for Cloud Monitoring in Singapore |
| title_short | GPS-Derived Slant Water Vapor for Cloud Monitoring in Singapore |
| title_sort | gps derived slant water vapor for cloud monitoring in singapore |
| topic | global positioning system (GPS) slant water vapor (<i>SWV</i>) slant wet delay (<i>SWD</i>) cloud monitoring whole sky imager |
| url | https://www.mdpi.com/2072-4292/14/21/5459 |
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