On the regulation of minimum mid‐tropospheric temperatures in the Arctic

Tsukernik, M.; Chase, Thomas N.; Barry, Roger G.; Pielke, Roger A.; Herman, Benjamin M.; Zeng, Xubin

doi:10.1029/2003gl018831

Cited by 11 publications

(10 citation statements)

References 14 publications

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“…Chase et al (2002) and Tsukernik et al (2004) suggest that, in the winter season, the Arctic SATs are indirectly linked to the sea surface temperatures (SSTs) of the open water areas. The winter SSTs in the Arctic are about Ϫ2°C, which by moist adiabatic convection processes implies temperatures at 500 hPa at about Ϫ45°C.…”

Section: Introductionmentioning

confidence: 99%

Do Changes in the Midlatitude Circulation Have Any Impact on the Arctic Surface Air Temperature Trend?

Graversen

2006

Journal of Climate

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The warming of the near-surface air in the Arctic region has been larger than the global mean surface warming. There is general agreement that the Arctic amplification of the surface air temperature (SAT) trend to a considerable extent is due to local effects such as the retreat of sea ice, especially during the summer months, and earlier melting of snow in the spring season. There is no doubt that these processes are important causes of the Arctic SAT trend. It is less clear, however, whether the trend may also be related to recent changes in the atmospheric midlatitude circulation. This question is the focus of the present paper.Model experiments have shown that in a warmer climate responding to, for example, a doubling of CO 2 , the atmospheric northward energy transport (ANET) will increase and cause polar SAT amplification. In the present study, the development of the ANET across 60°N and its linkage to the Arctic SAT have been explored using the ERA-40 reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF). It is found that during 1979-2001, the ANET has experienced an overall positive but weak trend, which was largest during the period from the mid-1980s to the mid-1990s. In addition, it is found that the Arctic SAT is sensitive to variability of the ANET across 60°N and hence to variability of the midlatitude circulation: A large ANET is followed by warming of the Arctic where ANET leads by about 5 days. The warming is located primarily north of the Atlantic and Pacific sectors, indicating that baroclinic weather systems developing around the Icelandic and Aleutian lows are important for the energy transport. Furthermore, it is suggested here that a small, but statistically significant, part of the mean Arctic SAT trend is linked to the trend in the ANET.Another important indicator of the midlatitude circulation is the Arctic Oscillation (AO). Through the 1980s and early 1990s the AO index has shown a positive trend. However, even though a part of the SAT trend can be related to the AO in localized parts of the Arctic area, the mean Arctic SAT trend shows no significant linkage to the AO.

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Section: Introductionmentioning

confidence: 99%

Do Changes in the Midlatitude Circulation Have Any Impact on the Arctic Surface Air Temperature Trend?

Graversen

2006

Journal of Climate

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“…The differential radiative heating is strongest in winter, during the Arctic polar night. The maximum high‐latitude poleward transport of atmospheric energy in winter is centered along the longitudes of the Greenland and Norwegian seas [ Tsukernik et al , 2004]. This area represents the northern end of the primary North Atlantic storm track, where a combination of strong transient eddy activity and open water overlain by a fairly cold atmosphere encourage large sensible and latent heat fluxes from the ocean to the atmosphere, increasing the convergence of energy transport in the Arctic region.…”

Section: Introductionmentioning

confidence: 99%

New estimates of the large‐scale Arctic atmospheric energy budget

2010

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[1] New estimates of the current energy budget of the north polar cap (the region north of 70°N) are synthesized by combining data from new atmospheric reanalyses and satellite retrievals. For the period 2000-2005, monthly means from the Clouds and the Earth's Radiant Energy System (CERES) satellite data set are considered to provide the most reliable top-of-atmosphere (TOA) radiation budget. The remaining components of the energy budget, comprising of the energy storage, horizontal convergence of energy, and the net surface flux between the atmospheric and subsurface columns, are compiled using data from the Japanese 25 Year Reanalysis Project (JRA) and the National Centers for Environmental Prediction (NCEP) /National Center for Atmospheric Research (NCAR) Reanalysis (NRA). The annual cycles of energy budget components for the polar cap are fairly consistent between the JRA and NRA, but with some systematic differences. JRA depicts an annual mean surface flux of 14 W m −2 (upward), compared to only 5 W m −2 in NRA. Most of this disparity appears to be due to differences in sea ice and albedo. Horizontal atmospheric energy flux divergence calculated using mass-corrected flux values contains artifacts leading to unphysical results. We argue that backing out the energy flux convergence as a residual from the net surface heat flux and time change in energy storage from each reanalysis, and the TOA radiation budget from CERES, provides for more physically realistic results in the Arctic. Monthly mean anomalies of budget terms, used to examine conditions leading to the extreme seasonal sea ice extent minimum of September 2005, point to the importance of albedo feedback.

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“…In several previous papers, [1][2][3] we provided observational and modeling evidence that the minimum Northern Hemisphere 500 mb temperature limit was convectively controlled. -42°C is the temperature expected from the moist adiabatic ascent of a convectively rising air mass after a shallow dry ascent from a surface temperature of -2.0°C, the coldest unfrozen seawater.…”

Section: Proposed Physical Mechanismmentioning

confidence: 99%

“…In several previous papers we have documented a cutoff in minimum 500 mb temperatures at high latitudes [1][2][3] using observational data from reanalyses and rawinsondes. The 500 mb level is both meteorologically significant (for example in frontal analysis and jet stream dynamics) and climatologically significant (e.g.…”

Section: Introductionmentioning

confidence: 99%

Bracketing Climatological Mid-tropospheric Temperatures in the Northern Hemisphere: An Observational Study 1979-2013

BM¹

2015

J Climatol Weather Forecasting

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We examine mid-tropospheric temperatures in the Northern Hemisphere using the 500 mb pressure surface from reanalysis data as a representative level. This standard analysis level is significant meteorologically (i.e. for frontal identification and jet stream dynamics) and climatologically (e.g. changes in long term front and jet structures would be expected to extend throughout the troposphere as would tropospheric warming). We find that 500 mb temperatures are bracketed between about -42°C and -3°C with very few excursions beyond these brackets suggesting a limiting physical process or processes. In this paper we update the data for the -42°C limit which we have proposed in previous papers, document the -3°C limit for the first time, and briefly discuss the possible physical mechanisms responsible for this observed temperature bracketing concluding that the limits on both maximum and minimum temperatures are due to convective processes. This self-regulation of tropospheric temperatures constrains changes in jet stream and baroclinic storm dynamics and therefore constrains changes in climate variability.

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On the regulation of minimum mid‐tropospheric temperatures in the Arctic

Cited by 11 publications

References 14 publications

Do Changes in the Midlatitude Circulation Have Any Impact on the Arctic Surface Air Temperature Trend?

Do Changes in the Midlatitude Circulation Have Any Impact on the Arctic Surface Air Temperature Trend?

New estimates of the large‐scale Arctic atmospheric energy budget

Bracketing Climatological Mid-tropospheric Temperatures in the Northern Hemisphere: An Observational Study 1979-2013

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