Discrimination of Cloud Pixels for Geostationary Satellite from MODIS Product

• Main Authors: Pin-yi Lee, 李品儀
• Other Authors: Hsuan Ren
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/76236809709425059220

碩士 === 國立中央大學 === 遙測科技碩士學位學程 === 101 === Clouds are a visible mass of liquid droplets or frozen crystals made of water or various chemicals suspended in the atmosphere. Seeing from a distance it is opaque, but closely it is discontinuous and can be seen through with certain visibility. When cloud existing, it will cover the earth's surface and weaken the information surface and lead to receive imprecise information. Therefore, before further analysis of the data, we should determine the cloud region first so that it can be filtered or corrected. However as mentioned, cloud is capricious, fuzzy and uncertain. This characteristic made the border of cloud uncertain and uneasy to determine whether the cloud existing or not. Therefore the identification is quite challenging. MODIS (Moderate-resolution Imaging Spectroradiometer) and MTSAT (Multifunctional Transport Satellites) are two major sources for cloud monitoring. MODIS is an important imager onboard the sun-synchronous satellites of Terra and Aqua. The advantages of MODIS are global observations, high spatial resolution and multi spectral. On the other hand, MTSAT is a geostationary satellite covered the Asia area which having a superiority of high temporal resolution. Therefore in order to get better temporal resolution to observe same location sustained, we combine MTSAT data collocates with MODIS cloud mask product－MOD35 to retrieve MTSAT cloud mask. This study focuses on the detection of clear pixels. The performance of the algorithm shows an almost perfect result by using kappa as standard compared to MODIS cloud mask.