@Article{PrudenteMaViSiAdSa:2020:LiClCo,
               author = "Prudente, Victor Hugo Rohden and Martins, Vitor Souza and Vieira, 
                         Denis Corte and Silva, Nildson Rodrigues de Fran{\c{c}}a and 
                         Adami, Marcos and Sanches, Ieda Del'Arco",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Iowa State 
                         University} and {Instituto Nacional de Pesquisas Espaciais (INPE)} 
                         and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Limitations of cloud cover for optical remote sensing of 
                         agricultural areas across South America",
              journal = "Remote Sensing Applications: Society and Environment",
                 year = "2020",
               volume = "20",
                pages = "e100414",
                month = "Nov.",
             keywords = "Crop monitoring, Optical data, Cloud frequency, MAIAC.",
             abstract = "Earth Observation data support the large-scale monitoring of 
                         croplands across South America (SA). For instance, optical remote 
                         sensing (ORS) data are typically used to map and monitor plant 
                         development during a crop season. However, the monitoring of 
                         agricultural areas is highly affected by cloud cover frequency 
                         (CCF), especially in the rainy season, and the implications of 
                         cloud cover for ORS of agricultural areas are still poorly 
                         understood in SA. In this study we evaluated the monthly CCF and 
                         variability focused on implications for agricultural monitoring in 
                         SA. Cloud cover was derived from daily MCD19A2 Collection 6 
                         Moderate Resolution Imaging Spectroradiometer (MODIS) product 
                         between 2000 and 2015. A monthly average was computed using daily 
                         observations for the studied period. To evaluate the effects of 
                         clouds in agricultural areas, we used a cropland mask from the 
                         Worldwide Croplands project and divided the CCF into quarters. The 
                         results show that cloud cover affects the monitoring of croplands 
                         depending on geographic location and crop season. In the P1 period 
                         (September to November) 68% of South American croplands have CCF 
                         between 40% and 60%. In the P2 period (December and February), SA 
                         croplands have CCF concentrated in the classes of 40%50% and 
                         70%80%. In the P3 period (March to May) 42% of SA croplands have 
                         CCF concentration in class 5 (40-50% of cloud cover). In the P4 
                         period (June to August), we observed values from 30% to 60% of 
                         cloud cover in 41% of South American croplands. These patterns 
                         make summer crop monitoring via ORS data difficult, mainly soybean 
                         and maize. In this sense, for the Brazilian states of Mato Grosso, 
                         Goias, Bahia, Tocantins, and Parana, the use of ORS is limited in 
                         providing an accurate summer crop monitoring. While cloud cover is 
                         an intrinsic challenge for agricultural monitoring of some crops, 
                         the combination of multi-sensors (e.g. microwave and optical 
                         sensors) and CubeSats can improve the earth observation frequency 
                         and help to work around this limitation, thus enabling a better 
                         time series analysis.",
                  doi = "10.1016/j.rsase.2020.100414",
                  url = "http://dx.doi.org/10.1016/j.rsase.2020.100414",
                 issn = "2352-9385",
             language = "en",
           targetfile = "prudente_limitations.pdf",
        urlaccessdate = "13 maio 2024"
}