The Response of Local Precipitation and Sea Level Pressure to Hadley Cell Expansion

AbstractHigh temporal resolution (three hours) records of temperature, wind speed and sea level pressure recorded at Antarctic research station Neumayer (70°S, 8°W) during 1982–2011 are analysed to identify oscillations from daily to intraseasonal timescales. The diurnal cycle dominates the three-hourly time series of temperature during the Antarctic summer and is almost absent during winter. In contrast, the three-hourly time series of wind speed and sea level pressure show a weak diurnal cycle. The dominant pattern of the intraseasonal variability of these quantities, which captures the out-of-phase variation of temperature and wind speed with sea level pressure, shows enhanced variability at timescales of ∼ 40 days and ∼ 80 days, respectively. Correlation and composite analysis reveal that these oscillations may be related to tropical intraseasonal oscillations via large-scale eastward propagating atmospheric circulation wave-trains. The second pattern of intraseasonal variability, which captures in-phase variations of temperature, wind and sea level pressure, shows enhanced variability at timescales of ∼ 35, ∼ 60 and ∼ 120 days. These oscillations are attributed to the Southern Annular Mode/Antarctic Oscillation (SAM/AAO) which shows enhanced variability at these timescales. We argue that intraseasonal oscillations of tropical climate and SAM/AAO are related to distinct patterns of climate variables measured at Neumayer.

Download Full-text

Tree-ring reconstructions of temperature and sea-level pressure variability associated with the warm-season Arctic Oscillation since AD 1650

Geophysical Research Letters ◽

10.1029/2003gl017250 ◽

2003 ◽

Vol 30 (11) ◽

Cited By ~ 46

Author(s):

Rosanne D. D'Arrigo

Keyword(s):

Sea Level ◽

Tree Ring ◽

Arctic Oscillation ◽

Warm Season ◽

Sea Level Pressure ◽

Level Pressure ◽

And Sea Level

Download Full-text

Mean Distribution of 500-mb Topography and Sea-Level Pressure in Middle and High Latitudes of the Northern Hemisphere during the 1950–59 Decade, January and July

Journal of Applied Meteorology ◽

10.1175/1520-0450(1963)002<0105:mdomta>2.0.co;2 ◽

1963 ◽

Vol 2 (1) ◽

pp. 105-113 ◽

Cited By ~ 1

Author(s):

Willam R. Gommel

Keyword(s):

Sea Level ◽

Northern Hemisphere ◽

High Latitudes ◽

Sea Level Pressure ◽

Level Pressure ◽

And Sea Level

Download Full-text

Influence of the Antarctic Oscillation, the Pacific–South American modes and the El Niño–Southern Oscillation on the Antarctic surface temperature and pressure variations

Antarctic Science ◽

10.1017/s095410201100054x ◽

2011 ◽

Vol 24 (1) ◽

pp. 59-76 ◽

Cited By ~ 8

Author(s):

Lejiang Yu ◽

Zhanhai Zhang ◽

Mingyu Zhou ◽

Sharon Zhong ◽

Donald Lenschow ◽

...

Keyword(s):

Surface Temperature ◽

Sea Level ◽

Southern Oscillation ◽

South American ◽

Antarctic Oscillation ◽

Sea Level Pressure ◽

Level Pressure ◽

The Pacific ◽

The Antarctic ◽

And Sea Level

AbstractIn this study, the impacts of the Antarctic Oscillation (AAO), the Pacific–South American teleconnection (PSA) and the El Niño–Southern Oscillation (ENSO) on Antarctic sea level pressure and surface temperature are investigated using surface observational data, European Centre for Medium-Range Weather Forecasts (ECMWF) 40 Year Re-analysis (ERA-40) and the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) re-analysis data from 1958–2001. There is the most significant correlation between PSA and Antarctic sea level pressure and surface temperature in the northern Antarctic Peninsula during four seasons. But the correlation between Southern Oscillation Index and surface temperature and sea level pressure is significant at some stations only in spring. The three indices can explain a large portion of the trends found in sea level pressure and temperature at some stations, but not at all stations. Among the three indices the most important contribution to the trends in the two surface variables comes from AAO, followed by PSA, and finally by ENSO. The two re-analysis datasets show great similarity for the trends in surface temperature and sea level pressure in April–May and October–November, but not December–February. In summer the trends in surface temperature and sea level pressure in East Antarctica for ERA-40 re-analysis are opposite to those of NCEP re-analysis.

Download Full-text

Improved Skill of Northern Hemisphere Winter Surface Temperature Predictions Based on Land–Atmosphere Fall Anomalies

Journal of Climate ◽

10.1175/jcli4241.1 ◽

2007 ◽

Vol 20 (16) ◽

pp. 4118-4132 ◽

Cited By ~ 74

Author(s):

Judah Cohen ◽

Christopher Fletcher

Keyword(s):

Snow Cover ◽

Sea Level ◽

Northern Hemisphere ◽

Land Surface ◽

Northern Eurasia ◽

Dynamical Models ◽

Sea Level Pressure ◽

Level Pressure ◽

Skill Scores ◽

And Sea Level

Abstract A statistical forecast model, referred to as the snow-cast (sCast) model, has been developed using observed October mean snow cover and sea level pressure anomalies to predict upcoming winter land surface temperatures for the extratropical Northern Hemisphere. In operational forecasts since 1999, snow cover has been used for seven winters, and sea level pressure anomalies for three winters. Presented are skill scores for these seven real-time forecasts and also for 33 winter hindcasts (1972/73–2004/05). The model demonstrates positive skill over much of the eastern United States and northern Eurasia—regions that have eluded skillful predictions among the existing major seasonal forecast centers. Comparison with three leading dynamical forecast systems shows that the statistical model produces superior skill for the same regions. Despite the increasing complexity of the dynamical models, they continue to derive their forecast skill predominantly from tropical atmosphere–ocean coupling, in particular from ENSO. Therefore, in the Northern Hemisphere extratropics, away from the influence of ENSO, the sCast model is expected to outperform the dynamical models into the foreseeable future.

Download Full-text

On the Summertime Strengthening of the Northern Hemisphere Pacific Sea Level Pressure Anticyclone

Journal of Climate ◽

10.1175/2008jcli2322.1 ◽

2009 ◽

Vol 22 (5) ◽

pp. 1174-1192 ◽

Cited By ~ 25

Author(s):

Sumant Nigam ◽

Steven C. Chan

Keyword(s):

Sea Level ◽

Northern Hemisphere ◽

Asian Monsoon ◽

Storm Track ◽

Hadley Cell ◽

Winter Storm ◽

Sea Level Pressure ◽

Level Pressure ◽

Mascarene High ◽

The Pacific

Abstract This study revisits the question posed by Hoskins on why the Northern Hemisphere Pacific sea level pressure (SLP) anticyclone is strongest and maximally extended in summer when the Hadley cell descent in the northern subtropics is the weakest. The paradoxical evolution is revisited because anticyclone buildup to the majestic summer structure is gradual, spread evenly over the preceding 4–6 months, and not just confined to the monsoon-onset period, which is interesting, as monsoons are posited to be the cause of the summer vigor of the anticyclone. Anticyclone buildup is moreover found focused in the extratropics, not the subtropics, where SLP seasonality is shown to be much weaker, generating a related paradox within the context of the Hadley cell’s striking seasonality. Showing this seasonality to arise from, and thus represent, remarkable descent variations in the Asian monsoon sector, but not over the central-eastern ocean basins, leads to the resolution of this paradox. Evolution of other prominent anticyclones is analyzed to critique the development mechanisms: the Azores high evolves like the Pacific one, but without a monsoon to its immediate west. The Mascarene high evolves differently, peaking in austral winter. Monsoons are not implicated in both cases. Diagnostic modeling of seasonal circulation development in the Pacific sector concludes this inquiry. Of the three forcing regions examined, the Pacific midlatitudes are found to be the most influential, accounting for over two-thirds of the winter-to-summer SLP development in the extratropics (6–8 hPa), with the bulk coming from the abatement of winter storm-track heating and transients. The Asian monsoon contribution (2–3 hPa) is dominant in the Pacific (and Atlantic) subtropics. The modeling results resonate with observational findings and attest to the demise of winter storm tracks as the principal cause of the summer vigor of the Pacific anticyclone.

Download Full-text