@article{KaiserWehrhanWerneretal.2012,
  author    = {Kaiser, Thomas and Wehrhan, Marc and Werner, Armin and Sommer, Michael},
  title     = {Regionalizing ecological moisture levels and groundwater levels in grassland areas using thermal remote sensing},
  series = {Grassland science},
  volume    = {58},
  journal   = {Grassland science},
  number    = {1},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {1744-6961},
  doi       = {10.1111/j.1744-697X.2011.00240.x},
  pages     = {42 -- 52},
  year      = {2012},
  abstract  = {Site-specific soil moisture and groundwater levels are key input parameters for ecological modeling. Obtaining such information in a comprehensive manner is difficult for large regions. We studied a floodplain region in the Federal State of Brandenburg, Germany, to examine the degree to which the average depth of groundwater tables can be derived from surface temperatures obtained by the ASTER radiospectrometer (spatial resolution of 90 m per pixel). A floristic ecological indicator representing the site-specific moisture level was applied to develop a proxy between the thermal satellite data and groundwater table depth. The use of spring scenes (late April to early May) from 2 years proved to be well suited for minimizing the effects of weather and land use. Vegetation surveys along transects that were 2 m wide across the pixel diagonals allowed for the calculation of average ecological moisture values of pixel-sites by applying Ellenberg-numbers. These values were used to calibrate the satellite data locally. There was a close relationship between surface temperature and the average ecological moisture value (R2 = 0.73). Average ecological moisture values were highly indicative of the average groundwater levels during a 7-year measurement series (R2 = 0.93). Satellite-supported thermal data from spring were suitable for estimating the average groundwater levels of low-lying grasslands on a larger scale. Ecological moisture values from the transect surveys effectively allowed the incorporation of relief heterogeneity within the thermal grid and the establishment of the correlation between thermal data and average groundwater table depth. Regression functions were used to produce a map of groundwater levels at the study site.},
  language  = {en}
}
@article{SoaresYamazakiMatzkaetal.2019,
  author    = {Soares, Gabriel and Yamazaki, Yosuke and Matzka, J{\"u}rgen and Pinheiro, Katia and Stolle, Claudia and Alken, Patrick and Yoshikawa, Akimasa and Uozumi, Teiji and Fujimoto, Akiko and Kulkarni, Atul},
  title     = {Longitudinal variability of the equatorial counter electrojet during the solar cycle 24},
  series = {Studia geophysica et geodaetica},
  volume    = {63},
  journal   = {Studia geophysica et geodaetica},
  number    = {2},
  publisher = {Springer},
  address   = {New York},
  issn      = {0039-3169},
  doi       = {10.1007/s11200-018-0286-0},
  pages     = {304 -- 319},
  year      = {2019},
  abstract  = {Ground and space-based geomagnetic data were used in the investigation of the longitudinal, seasonal and lunar phase dependence of the equatorial counter electrojet (CEJ) occurrence in the Peruvian, Brazilian, African, Indian and Philippine sectors during geomagnetically quiet days from the solar cycle 24 (2008 to 2018). We found that CEJ events occur more frequently during the morning (MCEJ) than in the afternoon (ACEJ). The highest MCEJ and ACEJ occurrence rates were observed for the Brazilian sector. Distinct seasonal dependence was found for each longitudinal sector under investigation. The lunar phase dependence was determined for the first time for the Philippine sector (longitude 125 degrees E), and it was shown to be less pronounced than in the Peruvian, Brazilian and African sectors. We demonstrate that differences in CEJ rates derived from ground-based and satellite data can arise from the longitudinal separation between low-latitude and equatorial stations that are used to determine the signal and its consequent time delay in their sunrise/sunset times at ionospheric heights.},
  language  = {en}
}