XXII ISPRS Congress 2012: Technical Commission VIII

Shortis, M.; Shimoda, H.; Cho, K.

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Multivolume work

Persistent identifier:: 1663813779

Title:: XXII ISPRS Congress 2012

Sub title:: Melbourne, Australia, 25 August-1 September 2012

Year of publication:: 2013

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663813779

Language:: English

Additional Notes:: Kongress-Thema: Imaging a sustainable future

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Document type:: Multivolume work

Volume

Persistent identifier:: 1663822514

Title:: Technical Commission VIII

Scope:: 590 Seiten

Year of publication:: 2014

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663822514

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(39,B8)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist ermittelt.; Literaturangaben

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Shortis, M.; Shimoda, H.; Cho, K.

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [VIII/3: Atmosphere, Climate and Weather]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: GROUND-BASED CLOUD OBSERVATION FOR SATELLITE-BASED CLOUD DISCRIMINATION AND ITS VALIDATION M. Yamashita, M. Yoshimura

Document type:: Multivolume work

Structure type:: Chapter

emperature 11 dominant fic surface e and time ne relative o surface > effective h reference us feature. specific que. The | enriched of local tion which M., 1998. spatial non- . M., 2002. nalysis of Sons Ltd, f mortality nvironment opment in nce as a g regional graphically Systems, 4, , 1976. A w tundra at heat island. 108, pp.1- sostatistical niology of resented at the Spatial >, Dunedin, eat Islands. resentation. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B8, 2012 XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia GROUND-BASED CLOUD OBSERVATION FOR SATELLITE-BASED CLOUD DISCRIMINATION AND ITS VALIDATION M. Yamashita *, M. Yoshimura ° * Survey College of Kinki, 1-5-9 Yata, Higashi-sumiyoshi-ku, Osaka, 546-0023, Japan -yamashita@kinsoku.ac.jp ? PASCO Corporation, Research and Development Center, 2-8-11 Higashiyama, Meguro-ku, Tokyo, 153-0043, Japan — mairtu1698@pasco.co.jp Commission VIII, WG VIII/3 KEY WORDS: Atmosphere, Weather, Development, Application, Radiation, Observations ABSTRACT: Solar radiation is a source of energy for ground surfaces. Clouds control energy budget on both local and global scales. We propose the simple ground-based observation method for various sky conditions instead of the existing visual observation. In the paper, we mainly describe how to discriminate clouds area on whole sky images, how to overlay the cloud areas to the satellite-based images and the test experiment. As for the discrimination of sky conditions, we use Sky Index (SI) and Brightness Index (BI) calculated from whole sky imageries. SI shows the extent of the blueness and grayscale and BI indicates the extent of the brightness. Sun, cloud and blue sky areas are divided by SI and BI threshold. As an extension of ground-based observation to satellite-based observation, clouds area discriminated by ground-based observation overlay to satellite images. Through this experiment, the utilities of ground-based cloud observation are discussed. The proposed ground-based cloud observation method and its satellite-based extension should be connected to satellite products with high quality by implementation of sky and clouds observation covering a wide area. 1. INTRODUCTION Clouds control energy budget on both local and global scales. Generally, it is well known that lower clouds cool the surface and upper clouds have the effects to warm the surface (Clement et al, 2009). Cumulus clouds especially in atmospheric boundary layer play crucial role in modulating the exchange of radiation, heat and moisture (Freedman et al. 2001). The size and the lifespan of cumulus clouds are small and short, therefore it is difficult to observe and monitor them spatially and temporally. Satellite-based observation and its products related to clouds properties have been useful to estimate some physical values such incident radiation/ Photosynthetic Active Radiation (PAR) and Fraction of PAR etc., and to be advanced various high quality satellite products. However, there are still some uncertainness such as cloud motion, cloud coverage, cloud type and these effects by satellite-based observation. Therefore, the efficient ground-based cloud observation is necessary to validate satellite-based observation such existing Terra & Aqua/ Moderate Resolution Imaging Spectroradiometer (MODIS) and under planning Global Change Observation Mission - Climate (GCOM-C) / Second generation GLobal Imager (SGLI) etc. Recently, the ground-based cloud observation systems have been developed by using whole sky camera in world widely instead of the existing visual observation (Calbo and Sabburg, 2008; Yamashita and Yoshimura, 2008; Heinle et al., 2010). The purpose of this study is to discriminate the cloud and overlay the cloud areas with satellite-based images by the efficient and simple ground-based cloud observation using commercial based digital camera and fish eye lens in order to validate the satellite-based observation. In the paper, we mainly describe how to discriminate the cloud area on whole sky Images, how to overlay the cloud areas to the satellite-based images and the test experiment. Through this experiment, the utilities of ground-based cloud observation are discussed. 2. GROUND-BASED CLOUD OBSERVATION 2.1 Camera system Automatic-capturing Digital Fisheye Camera (ADFC) is the instruments to take and accumulate the whole sky imageries. ADFC consists of digital camera (Nikon, Coolpix4500) with fisheye lens (Nikon, Fisheye Converter FC-E8), waterproof hard case and remote controlled cable connected to PC (Tsuchida et al, 2005). In order to decrease the influence for CCD saturation caused by the strong sun light, the neutral density filter with 10% transparency (FUJIFILM, ND1.0) puts between the digital camera and the fisheye lens. The camera is set up to take imageries at every two-minute interval by fixed exposure of the aperture as F2.6 and shutter speed as 1/500s. The image size has 2204pixels by 1704lines with RGB colors and JPEG (1/4 compressed) format instead of RAW or Tiff format to accumulate the large volume of image files. In this study, we already have confirmed that the almost no influences between JPEG (1/4 compressed) and RAW/Tiff formats after image processing. Also, digital number (DN) of RGB channels can be used instead of radiance by fixing aperture and exposure. The head of digital camera of ADFC is fixed to north direction and levelled to horizon. 2.2 Discrimination of cloud, blue sky and sun The sky conditions consist of each state of sun, clouds and blue sky. In order to discriminate the sky conditions from whole sky imageries, we use two indices which show the levels of the blueness/greyscale and the brightness calculated from the imageries. Here, the method how to discriminate the sky condition is described. Figure 1 shows the flowchart to classify cloud and blue sky areas from the whole sky imagery taken at the time (7).

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