Vertical structure of low-level atmosphere over the southeast Indian Ocean fronts

• Main Authors: Lin, Feng, Lin, Liu, Libao, Gao, Weidong, Yu
• Format: Article in Journal/Newspaper
• Language: English
• Published: Polar Research Institute of China - PRIC 2012
• Subjects: Atmosphere; Oceans; Antarctic; The Antarctic; Indian; Advances in Polar Science; Antarc*; Polar Science
• Online Access: http://library.arcticportal.org/2461/; http://library.arcticportal.org/2461/1/A20120305.pdf

During the 25th Chinese National Antarctic Research Expedition, GPS radiosondes were launched to detect the atmospheric vertical structure over the southeast Indian Ocean frontal region. Some low-level characteristics along the cruise are studied based on in-situ observation. The observations reveal that vertical distributions of the low-level wind field and air temperature field on both sides of the Subantarctic Front are very different. A stronger (weaker) vertical gradient is on the cold (warm) side, which demonstrates that the mid-latitude ocean-atmosphere interaction is active in the southeast Indian Ocean frontal region. A low-level jet is observed over the Subantarctic Front, with speed up to 14 m·s-1. For the Antarctic polar front, low-level wind speed near the sea surface is greater than that aloft, in contrast with the situation of the Subantarctic Front. Comparing satellite remote sensing data and widely-used reanalysis datasets with our in-situ observations, differences of varying magnitudes are found. Air temperature from Atmospheric Infrared Sounder (AIRS) data has a limited difference. The European Center for Medium Range Weather Forecasts Interim Re-Analysis (ERA Interim) dataset is much more consistent with the observations than the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis 1 in the southeast Indian Ocean frontal region.