The Cryosphere | 2019
Moisture transport in observations and reanalyses as a proxy for snow accumulation in East Antarctica
Abstract
Abstract. Atmospheric\nmoisture convergence on ice sheets provides an estimate of snow accumulation,\nwhich is critical to quantifying sea-level changes. In the case of East\nAntarctica, we computed moisture transport from 1980 to 2016 in five\nreanalyses and in radiosonde observations. Moisture convergence in reanalyses\nis more consistent than net precipitation but still ranges from 72 to\n96\u2009mm\u2009yr −1 in the four most recent reanalyses, ERA-Interim, NCEP CFSR,\nJRA\xa055 and MERRA\xa02. The representation of long-term variability in reanalyses\nis also inconsistent, which justified resorting to observations. Moisture fluxes are measured on a daily basis via radiosondes launched from a\nnetwork of stations surrounding East Antarctica. Observations agree with\nreanalyses on the major role of extreme advection events and transient eddy\nfluxes. Although assimilated, the observations reveal processes that reanalyses\ncannot model, some due to a lack of horizontal and vertical resolution,\nespecially the oldest, NCEP DOE\xa0R2. Additionally, the observational time\nseries are not affected by new satellite data unlike the reanalyses. We formed\npan-continental estimates of convergence by aggregating anomalies from all\navailable stations. We found statistically significant trends neither in\nmoisture convergence nor in precipitable water.