The Antarctic First Regional Observing Study of the Troposphere (FROST) Project

Turner, John; Bromwich, David H.; Colwell, S. R.; Dixon, Stephen; Gibson, T; Hart, T.; Heinemann, Günther; Hutchinson, Hugh A.; Jacka, Kieran; Leonard, Steven; Lieder, Michael; Marsh, Lawrie; Pendlebury, Stephen; Phillpot, H. R.; Pook, Michael J.; Simmonds, Ian

doi:10.1175/1520-0477(1996)077<2007:tafros>2.0.co;2

Cited by 60 publications

(26 citation statements)

References 31 publications

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“…Despite the magnitude differences, the vector directions are in reasonable agreement for all of East Antarctica, particularly for South Pole and along Shackleton Coast, west of the Ross Ice Shelf. Over West Antarctica there is more substantial disagreement in the vector-averaged wind directions (Turner et al 1996). This may be due in part to the South Pacific blocking conditions present during the July SOP, which are not present in the mesoscale model.…”

Section: Initial-hour Comparisons With Observations and Climatologiesmentioning

confidence: 95%

“…# Current affiliation: Department of Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado. national collaboration of the Scientific Committee on Antarctic Research Working Group on Physics and Chemistry of the Atmosphere, with principal goals of examining the performance of operational analyses and forecasts for Antarctica and the surrounding sea-ice zone during three 1-month-long SOPs in July 1994, October-November 1994, and January 1995 (Turner et al 1996). In high southern latitudes, weather data assimilation and prediction face an array of obstacles that limit operational performance, including the scarcity of available data and long-distance communications difficulties.…”

Section: Introductionmentioning

confidence: 99%

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An Assessment of the NCEP Operational Global Spectral Model Forecasts and Analyses for Antarctica during FROST*

Bromwich

Cullather²,

Grumbine³

1999

Wea. Forecasting

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Analyses and medium-range numerical weather forecasts produced by the National Centers for Environmental Prediction are evaluated poleward of 50ЊS during the July 1994 special observing period of the Antarctic First Regional Observing Study of the Troposphere project. Over the Antarctic plateau, the poor representation of the continent's terrain creates ambiguity in assessing the quality of surface variables. An examination of the vertical temperature profile, however, finds the near-surface temperature inversion strength to be substantially smaller than the observed climatology at the zero forecast hour. This arises from surface temperatures that are warmer than expected. Significant adjustment occurs in a variety of fields over the first few days of the mediumrange forecast, which likely results from the initial hour's suspect temperature profile. A spatially oscillating series of forecast anomalies in the zonally averaged temperature cross section stretches to middle latitudes by day 3. Near-surface and upper-troposphere values are found actually to improve at the South Pole with forecast time, although some fields continue to adjust through day 7. Although the examination presented here does not give a complete diagnosis, differences between observations and analyses suggest deficiencies with the model initial fields have a major role in producing the substantial model drift found. Atmospheric moisture over the continental interior does not change significantly with forecast hour, although the distinct contrast between nearshore and interior conditions lessens with forecast time. A spurious high-latitude wave pattern is found for a variety of variables. The pattern of this distortion remains constant with forecast hour. Over the ocean, large forecast pressure and height differences with analyses are associated with blocking conditions. However, it is unclear whether this results from deficiencies in the forecast model or the meager observational network over the Southern Ocean.

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Section: Initial-hour Comparisons With Observations and Climatologiesmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

An Assessment of the NCEP Operational Global Spectral Model Forecasts and Analyses for Antarctica during FROST*

Bromwich

Cullather²,

Grumbine³

1999

Wea. Forecasting

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“…These factors result in forecasts and analyses that are of poorer quality compared with other parts of the world (Bourke 1996). This problem has been addressed by the international Scientific Committee on Antarctic Research Working Group on Physics and Chemistry of the Atmosphere by advancing the FROST project as a research and data gathering exercise to evaluate the potential for improving the present situation (Bromwich and Smith 1993;Turner et al 1996).…”

Section: W E a T H E R A N D F O R E C A S T I N Gmentioning

confidence: 99%

“…The primary goal of FROST is to examine the performance of operational analyses and forecasts for Antarctica and the surrounding sea ice zone during three 1-month-long special observing periods (SOPs): (a) SOP-1 (winter) during July 1994, (b) SOP-2 (spring) during 15 October-15 November 1994, and (c) SOP-3 (summer) during January 1995 (Bromwich and Smith 1993;Turner et al 1996). The U.S. component of this project is an evaluation of analyses and forecasts produced by NCEP.…”

Section: W E a T H E R A N D F O R E C A S T I N Gmentioning

confidence: 99%

Surface Energy Balance of the NCEP MRF and NCEP–NCAR Reanalysis in Antarctic Latitudes during FROST*

Hines¹,

Grumbine²,

Bromwich³

et al. 1999

Wea. Forecasting

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The surface energy budget in Antarctic latitudes is evaluated for the medium-range numerical weather forecasts produced by the National Centers for Environmental Prediction (NCEP) and for the NCEP-National Center for Atmospheric Research reanalysis project during the winter, spring, and summer special observing periods (SOPs) of the Antarctic First Regional Observing Study of Troposphere project. A significant change in the energy balance resulted from an extensive model update beginning with the forecasts initialized on 11 January 1995 during the summer SOP. Both the forecasts and the reanalysis include significant errors in the surface energy balance over Antarctica. The errors often tend to cancel and thus produce reasonable surface temperature fields. General errors include downward longwave radiation about 30-50 W m Ϫ2 too small. Lower than observed cloudiness contributes to this error and to excessive downward shortwave radiation at the surface. The model albedo over Antarctica, about 75%, is lower than that derived from observations, about 81%. During the polar day, errors in net longwave and net shortwave radiation tend to cancel. The energy balance over Antarctica in the reanalysis is, in general, degraded from that of the forecasts.Seasonal characteristics of the surface energy balance include cooling over East Antarctica and slight warming over West Antarctica during NCEP forecasts for the winter SOP. Wintertime surface warming by downward sensible heat flux is larger than observations by 21-36 W m Ϫ2 and tends to balance the excessive longwave cooling at the surface. During the spring SOP, forecast sensible heat flux produces an excessive heating contribution by about 20 W m Ϫ2 . Latent heat flux during the Antarctic winter for the reanalysis is at least an order of magnitude larger than the very small observed values.

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“…Using observations from the Antarctic First Regional Observing Study of the Troposphere (FROST) in 1994-1995, Bromwich and Smith (1993, Turner et al (1996), and Turner et al (1999) found that the NCEP-NCAR and ECMWF reanalysis are able to produce the main circulation features over Antarctica, despite some minor discrepancies in the depths and locations of the lows. Cullather et al (1997) compared the two reanalysis products for a 10-yr (1985-1995) period and found that surface pressure in the two reanalysis datasets is in better agreement with observations than surface air temperature and wind, and that the errors in both reanalysis at the standard pressure levels decrease with time.…”

Section: Introductionmentioning

confidence: 99%

Validation of ECMWF and NCEP-NCAR reanalysis data in Antarctica

Zhang

Zhou

et al. 2010

Adv. Atmos. Sci.

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The European Center for Medium-Range Weather Forecast (ECMWF) Re-Analysis (ERA-40) and the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) ECMWF (ERA-40) and NCEP-NCAR reanalysis data were compared with Antarctic station observations, including surface-layer and upper-layer atmospheric observations, on intraseasonal and interannual timescales. At the interannual timescale, atmospheric pressure at different height levels in the ERA-40 data are in better agreement with observed pressure than that in the NCEP-NCAR reanalysis data. ERA-40 reanalysis also outperforms NCEP-NCAR reanalysis in atmospheric temperature, except in the surface layer where the biases are somewhat larger. The wind velocity fields in both datasets do not agree well with surface-and upper-layer atmospheric observations. At intraseasonal timescales, both datasets capture the observed intraseasonal variability in pressure and temperature during austral winter.

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The Antarctic First Regional Observing Study of the Troposphere (FROST) Project

Cited by 60 publications

References 31 publications

An Assessment of the NCEP Operational Global Spectral Model Forecasts and Analyses for Antarctica during FROST*

An Assessment of the NCEP Operational Global Spectral Model Forecasts and Analyses for Antarctica during FROST*

Surface Energy Balance of the NCEP MRF and NCEP–NCAR Reanalysis in Antarctic Latitudes during FROST*

Validation of ECMWF and NCEP-NCAR reanalysis data in Antarctica

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