Decadal-length composite inland West Antarctic temperature records

Decadal-length, daily average, temperature records have been generated for four inland West Antarctic sites by combining automatic weather station (AW S) and satellite passive microwave brightness temperature records. These re cords are composites due to the difficulty in maintaining continuously oper ating AWS in Antarctica for multiyear to multidecade periods. Calibration o f 37-GHz, vertical polarization, brightness temperature data during periods of known air temperature by emissivity modeling allows the resulting calib rated brightness temperatures (TC) to be inserted into data gaps with const rained errors. By the same technique, but with reduced constraints, TC data were also developed through periods before AWS unit installation or after removal. The resulting composite records indicate that temperature change is not con sistent in sign or magnitude from location to location across the West Anta rctic region. Linear regression analysis shows an approximate 0.9 degreesC increase over 19 yr at AWS Byrd (0.045 yr(-1) +/-0.135 degreesC), a 0.9 deg reesC cooling over 12 yr at AWS Lettau (-0.078 yr-1 +/-0.178 degreesC), a 3 degreesC cooling over 10 yr at AWS Lynn (-0.305 yr(-1) +/-0.314 degreesC), and a 2 degreesC warming over 19 yr at AWS Siple (0.111 yr(-1) +/-0.079 de greesC). Only the Siple trend is statistically significant at the 95% confi dence level however. The temperature increases at Siple and possibly Byrd a re suggestive of a broader regional warming documented at sites on the Anta rctic Peninsula. The cooling suggested by the shorter records in the vicini ty of the Ross Ice Shelf is consistent with results recently reported by Co miso and suggests that significant regional differences exist. Continued da ta acquisition should enable detection of the magnitude and direction of po tential longer-term changes.