Abstract
This study introduces temporal and spatial variations of microwave radiation at the slope area of Antarctica based on in situ microwave observations. The observations were conducted by using portable microwave radiometers of 6, 18, and 36 GHz in January 2017. The continuous observation at S17 showed a rapid increase of brightness temperature of all frequencies in daytime. Snow melting seems to have caused this increase. The largest increase of brightness temperature was observed with the low frequency band of 6 GHz horizontal polarization. The amount of increase was 70 K. The higher frequencies of 36 and 18 GHz showed an earlier increase, followed by the increase at the low frequency of 6 GHz. This time difference is expected because the lower frequency may be influenced by emission from the deeper snow layer. As determined from observation along the 80km traverse route between S17 and H128, the brightness temperature increased generally toward the inland; however, the lowest brightness temperature was observed locally around S17. The refrozen ice layers in the coastal snow layers seem to have caused the low emission at S17. Although the satellite microwave observation could reveal the general decrease of brightness temperature from coast to inland, the local low brightness temperature around S17 was not revealed clearly. The satellite observation showed a 5K increase when the in situ observation recorded a large increase of 70 K. These results imply that the satellite observation missed some local and temporal variations.
