|dc.description.abstract||A soil climate station network in the Ross Sea region of Antarctica comprises; Cape Hallett (72.19°S, 2 m asl), Granite Harbour (77°S, 6 m asl), Victoria Valley (77.19°S, 408 m asl), Marble Point (77.25°S, 55 m asl), Bull Pass East (77.30°S, 833 m asl), Wright Valley (77.31°S, 155 m asl), Mt Fleming (77.32°S, 1690 m asl), Scott Base (77.50°S, 51 m asl), Minna Bluff (78.30°S, 28 m asl), and Darwin Glacier (79.50°S, 333 m asl). Variables measured include air and soil temperatures to 1.2 m depth, and wind speed and direction. The overall objectives of this study were to; investigate the trends in air and soil temperatures across latitudinal and altitudinal gradients from Cape Hallett (72°S) to Darwin Glacier (79.5°S), and from sea level to the edge of the Polar Plateau; quantify the cumulative number of days when air and soil temperatures were ≥0°C; and to analyse the wind data to characterise the wind regime at each site and to investigate storm events and diurnal patterns.
Mean annual air temperatures were, from warmest to coolest: Cape Hallett ( 15.3°C), Granite Harbour ( 16.6°C), Marble Point ( 17.6°C), Darwin Glacier ( 18.2°C), Minna Bluff ( 18.3°C), Scott Base ( 19.1°C), Wright Valley ( 19.6°C), and Victoria Valley ( 22.4°C). Two stations had a warming trend (P<0.05); Marble Point (in air, and in soil at 7.5 and 120 cm depth) and Granite Harbour (in soil at 5.5 cm depth). No significant trends of warming or cooling were observed at the Cape Hallett, Darwin Glacier, Minna Bluff, Scott Base, Wright Valley, Victoria Valley, or Mt Fleming sites. Shallow soil temperatures were warmer than air temperatures, apparently due to heating from solar radiation in summer, and snow insulation in winter.
The mean cumulative days/summer with air temperature ≥0°C ranged from: Wright Valley (33.3), Victoria Valley (22.3), Granite Harbour (10.4), Marble Point (9.7), Minna Bluff (7.6), Darwin Glacier (7.3), Scott Base (4.2), to Mt Fleming (0.0). In shallow soil (~5 cm depth), the mean cumulative number of days/summer with T≥0°C were: Wright Valley (69.8), Granite Harbour (69.6), Marble Point (55.5), Minna Bluff (52.8), Victoria Valley (50.2), Scott Base (34.6), Cape Hallett (32.2), to Mt Fleming (0.0). At the mid-depth soil (~20 cm depth), the overall cumulative numbers of days with T≥0°C were: Granite Harbour (65.5), Wright Valley (52.0), Marble Point (44.7), Minna Bluff (31.6), Cape Hallett (22.5), Scott Base (13.9), Victoria Valley (1.8), and Mt Fleming (0.0). There was no increasing or decreasing trend in the days with air or soil T≥0°C over the record period.
Mean annual wind speeds were: Darwin Glacier (45 kmhr-1), Minna Bluff (42 kmhr-1), Mt Fleming (29 kmhr-1), Scott Base (17 kmhr-1), Wright Valley (14 kmhr-1), Marble Point (12 kmhr-1), Victoria Valley (8 kmhr-1), and Granite Harbour (7 kmhr-1). The highest recorded mean hourly wind speed was 169 kmhr 1 at Minna Bluff in 2009. There was increasing wind speed with increased latitude (R2=0.59), but no relationship between wind speed and altitude. Controls on wind speed and direction were likely to be a combination of altitude, latitude, local topography, and cyclonic storms.||