An Assessment of Precipitation Changes over Antarctica and the Southern Ocean since 1989 in Contemporary Global Reanalyses*

Bromwich, David H.; Nicolas, Julien P.; Monaghan, Andrew J.

doi:10.1175/2011jcli4074.1

Cited by 268 publications

(255 citation statements)

References 74 publications

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“…The relative accuracy of contemporary reanalyses has been examined previously in relation to predicted precipitation, and ERA-Interim fared the best [Nicolas and Bromwich, 2011;Bromwich et al, 2011b]. In addition, from a comparison of five reanalyses with Antarctic station observations [Bracegirdle and Marshall, 2012], ERA-Interim was found to be the most reliable for mean sea level pressure and 500 hPa height trends.…”

Section: Introductionmentioning

confidence: 89%

Comprehensive evaluation of polar weather research and forecasting model performance in the Antarctic

et al. 2013

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[1] Recent versions of the Polar Weather Research and Forecasting model are evaluated over the Antarctic to assess the impact of model improvements, resolution, large-scale circulation variability, and uncertainty in initial and lateral boundary conditions. The model skill differs more between forecasts using different sources of lateral boundary data than between forecasts from different model versions or simulated years. Using the ERA-Interim reanalysis for initial and lateral boundary conditions produces the best skill. The forecasts have a cold summer and a warm winter bias in 2 m air temperatures, with similar but smaller bias in dew point temperatures. Upper air temperature biases are small and remain less than 1 C except at the tropopause in summer. Geopotential height biases increase with height in both seasons. Deficient downward longwave radiation in all seasons and an under representation of clouds enhance radiative loss, leading to the cold summer bias. Excess summer surface incident shortwave radiation plays a secondary role, because 80% of it is reflected, leading to greater skill for clear compared with cloudy skies. The positive wind speed bias produces a warm surface bias in winter resulting from anomalously large downward flux of sensible heat toward the surface. Low temperatures on the continent limit sublimation and hence the precipitable water amounts over the ice sheet. ERA-Interim experiments with higher precipitable water showed reduced biases in downwelling shortwave and longwave radiation. Increasing horizontal resolution from 60 to 15 km improves the skill of surface wind forecasts.

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Section: Introductionmentioning

confidence: 89%

Comprehensive evaluation of polar weather research and forecasting model performance in the Antarctic

et al. 2013

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“…While the deeper layers show a seasonal SSA evolution, the surface layer mostly reflects day-to-day variations of weather conditions. To simulate the evolution of the snowpack at Dome C, it is thus critical to know precipitation very precisely, a quantity that is difficult to obtain from reanalyses in Antarctica (Bromwich et al, 2011). In practice, ERAInterim reanalysis sometimes misses precipitation events at Dome C (Fig.…”

Section: Metamorphism Snowfall and Wind-driven Ssa Variationsmentioning

confidence: 99%

Summertime evolution of snow specific surface area close to the surface on the Antarctic Plateau

et al. 2015

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Abstract. On the Antarctic Plateau, snow specific surface area (SSA) close to the surface shows complex variations at daily to seasonal scales which affect the surface albedo and in turn the surface energy budget of the ice sheet. While snow metamorphism, precipitation and strong wind events are known to drive SSA variations, usually in opposite ways, their relative contributions remain unclear. Here, a comprehensive set of SSA observations at Dome C is analysed with respect to meteorological conditions to assess the respective roles of these factors. The results show an average 2-to-3-fold SSA decrease from October to February in the topmost 10 cm in response to the increase of air temperature and absorption of solar radiation in the snowpack during spring and summer. Surface SSA is also characterized by significant daily to weekly variations due to the deposition of small crystals with SSA up to 100 m 2 kg −1 onto the surface during snowfall and blowing snow events. To complement these field observations, the detailed snowpack model Crocus is used to simulate SSA, with the intent to further investigate the previously found correlation between interannual variability of summer SSA decrease and summer precipitation amount. To this end, some Crocus parameterizations have been adapted to Dome C conditions, and the model was forced by ERAInterim reanalysis. It successfully matches the observations at daily to seasonal timescales, except for the few cases when snowfalls are not captured by the reanalysis. On the contrary, the interannual variability of summer SSA decrease is poorly simulated when compared to 14 years of microwave satellite data sensitive to the near-surface SSA. A simulation with disabled summer precipitation confirms the weak influence in the model of the precipitation on metamorphism, with only 6 % enhancement. However, we found that disabling strong wind events in the model is sufficient to reconciliate the simulations with the observations. This suggests that Crocus reproduces well the contributions of metamorphism and precipitation on surface SSA, but snow compaction by the wind might be overestimated in the model.

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“…Recent reconstructions of Antarctic SAT suggest that West Antarctica has probably warmed since the 1950s (Steig et al 2009;O'Donnell et al 2011), but there is disagreement in the spatial extent, seasonality, and magnitude of the trends. Perhaps the most persuasive evidence is a recently compiled reconstruction of SAT for Byrd Station in central West Antarctica (808S, 1208W), which revealed an annually averaged warming rate of ;0.58C decade 21 between 1958 and 2010, substantially greater than the global average (Bromwich et al 2013). Pronounced warming of this region over the past ;100 years has also been detected from ice cores (Schneider and Steig 2008).…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Amundsen–Bellingshausen Seas Low on the Climate of West Antarctica and Its Representation in Coupled Climate Model Simulations

et al. 2013

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In contrast to earlier studies, the authors describe the climatological deep low pressure system that exists over the South Pacific sector of the Southern Ocean, referred to as the Amundsen-Bellingshausen Seas low (ABSL), in terms of its relative (rather than actual) central pressure by removing the background areaaveraged mean sea level pressure (MSLP). Doing so removes much of the influence of large-scale variability across the ABSL sector region (e.g., due to the southern annular mode), allowing a clearer understanding of ABSL variability and its effect on the regional climate of West Antarctica. Using ECMWF Interim ReAnalysis (ERA-Interim) fields, the annual cycle of the relative central pressure of the ABSL for the period from 1979 to 2011 shows a minimum (maximum) during winter (summer), differing considerably from the earlier studies based on actual central pressure, which suggests a semiannual oscillation. The annual cycle of the longitudinal position of the ABSL is insensitive to the background pressure, and shows it shifting westward from ;2508 to ;2208E between summer and winter, in agreement with earlier studies. The authors demonstrate that ABSL variability, and in particular its longitudinal position, play an important role in controlling the surface climate of West Antarctica and the surrounding ocean by quantifying its influence on key meteorological parameters. Examination of the ABSL annual cycle in 17 CMIP5 climate models run with historical forcing shows that the majority of them have definite biases, especially in terms of longitudinal position, and a correspondingly poor representation of West Antarctic climate.

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An Assessment of Precipitation Changes over Antarctica and the Southern Ocean since 1989 in Contemporary Global Reanalyses*

Cited by 268 publications

References 74 publications

Comprehensive evaluation of polar weather research and forecasting model performance in the Antarctic

Comprehensive evaluation of polar weather research and forecasting model performance in the Antarctic

Summertime evolution of snow specific surface area close to the surface on the Antarctic Plateau

The Influence of the Amundsen–Bellingshausen Seas Low on the Climate of West Antarctica and Its Representation in Coupled Climate Model Simulations

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