Title A case study of a Ross Ice Shelf airstream event; a new perspective
Author Steinhoff, D.F.; Chaudhuri, S.; Bromwich, D.H.
Author Affil Steinhoff, D.F., Ohio State University, Department of Geography, Columbus, OH
Source Monthly Weather Review, 137(11), p.4030-4046, . Publisher: American Meteorological Society, Washington, DC, United States. ISSN: 0027- 0644
Publication Date Nov. 2009
Notes In English. Based on Publisher- supplied data Ant. Acc. No: 90987. GeoRef Acc. No: 308190
Index Terms atmospheric circulation; clouds (meteorology); forecasting; remote sensing; storms; Antarctica--Ross Ice Shelf; airflow; Antarctica; case studies; clouds; cyclones; imagery; MODIS; prediction; Ross Ice Shelf; satellite methods; winds
Abstract A case study illustrating cloud processes and other features associated with the Ross Ice Shelf airstream (RAS), in Antarctica, is presented. The RAS is a semipermanent low- level wind regime primarily over the western Ross Ice Shelf, linked to the midlatitude circulation and formed from terrain-induced and large-scale forcing effects. An integrated approach utilizes Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery, automatic weather station (AWS) data, and Antarctic Mesoscale Prediction System (AMPS) forecast output to study the synoptic-scale and mesoscale phenomena involved in cloud formation over the Ross Ice Shelf during a RAS event. A synoptic-scale cyclone offshore of Marie Byrd Land draws moisture across West Antarctica to the southern base of the Ross Ice Shelf. Vertical lifting associated with flow around the Queen Maud Mountains leads to cloud formation that extends across the Ross Ice Shelf to the north. The low-level cloud has a warm signature in thermal infrared imagery, resembling a surface feature of turbulent katabatic flow typically ascribed to the RAS. Strategically placed AWS sites allow assessment of model performance within and outside of the RAS signature. AMPS provides realistic simulation of conditions aloft but experiences problems at low levels due to issues with the model PBL physics. Key meteorological features of this case study, within the context of previous studies on longer time scales, are inferred to be common occurrences. The assumption that warm thermal infrared signatures are surface features is found to be too restrictive.
URL http://hdl.handle.net/10.1175/2009MWR2880.1
Publication Type journal article
Record ID 65005109