The Mobile Polar High: a new concept explaining present mechanisms of meridional air-mass and energy exchanges and global propagation of palaeoclimatic changes

Leroux, Marcel

doi:10.1016/0921-8181(93)90041-l

Cited by 73 publications

(34 citation statements)

References 55 publications

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“…Letters indicate site name: Z: Zagoskin Lake, AK; K: Klamath Lake CA; La: Lake Lahontan, NV; O: Owens Lake, CA; E: Estancia Lake, NM; Ba: Cuenca de Babicora, Mexico; P: Lago de Patzcuaro, Mexico; Q: Laguna Quexil, Mexico; Y: La Yeguada, Panama; Li: Laguna Los Lirios, Venezuela; V: Lago de Valencia, Venezuela; F: Laguna de Fuquene, Colombia; S: Laguna Surucucho; J: Laguna Junin, Peru; T: Lago de Titicaca, Peru; U: Salar de Uyuni, Bolivia; Le: Laguna Lejia, Chile; Be: Salinas del Bebedero, Argentina; CL: Cari Laufquen Grande, Argentina; Ca: Lago Cardiel, Argentina. moisture sources by the e!ects of mobile polar highs as suggested by Leroux (1993) and Marengo and Rogers (1999).…”

Section: Late Pleistocene Lake Recordsmentioning

confidence: 96%

Paleoclimate reconstruction along the Pole–Equator–Pole transect of the Americas (PEP 1)

Markgraf

Baumgartner

Bradbury

et al. 2000

Quaternary Science Reviews

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Examples are presented of inter-hemispheric comparison of instrumental climate and paleoclimate proxy records from the Americas for di!erent temporal scales. Despite a certain symmetry of seasonal precipitation patterns along the PEP 1 transect, decadal variability of winter precipitation shows di!erent characteristics in terms of amplitude and frequency in both the last 100 and last 1000 years. Such di!erences in variability are also seen in a comparison of time series of di!erent El Nin o/Southern Oscillation proxy records from North and South America, however, these di!erences do not appear to a!ect the spatial correlation with Paci"c sea surface temperature patterns. Local and regional di!erences in response to climate change are even more pronounced for records with lower temporal resolution, and inter-hemispheric synchroneity may or may not be indicative of the same forcing. This aspect is illustrated in an inter-hemispheric comparison of the last 1000 years of glacier variability, and of the full-and lateglacial lake level history.

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Section: Late Pleistocene Lake Recordsmentioning

confidence: 96%

Paleoclimate reconstruction along the Pole–Equator–Pole transect of the Americas (PEP 1)

Markgraf

Baumgartner

Bradbury

et al. 2000

Quaternary Science Reviews

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“…The glacier advance is most likely due to a global cold pulse , which could have forced the westerly wind belt northward, thereby causing higher rainfall in mid-latitude Chile. Leroux (1993) has shown that the intensity of cyclones in the Southern Westerlies is directly controlled by outbreaks of cold air from polar regions, and thus by high-latitude temperature.…”

Section: Paleoclimatic Implicationsmentioning

confidence: 99%

“…Enhanced aridity in this area might be related to the strength of the Southeast Pacific Anticyclone, which reached its maximum intensity during the deglaciation (Villagrán, 1993), possibly forcing the Southern Westerlies into a southern position. In addition, increasing temperatures in Antarctica might have reduced outbreaks of polar air, decreasing the intensity of mid-latitude cyclones (Leroux, 1993).…”

Section: Late-glacial To Early Holocene (18000 -8000 Cal Yr Bp)mentioning

confidence: 99%

High-Resolution Marine Record of Climatic Change in Mid-latitude Chile during the Last 28,000 Years Based on Terrigenous Sediment Parameters

1999

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Marine sediment cores from the continental slope off midlatitude Chile (33°S) were studied with regard to grain-size distributions and clay mineral composition. The data provide a 28,000-yr 14 C accelerator mass spectrometry-dated record of variations in the terrigenous sediment supply reflecting modifications of weathering conditions and sediment source areas in the continental hinterland. These variations can be interpreted in terms of the paleoclimatic evolution of mid-latitude Chile and are compared to existing terrestrial records. Glacial climates (28,000 -18,000 cal yr B.P.) were generally cold-humid with a coldsemiarid interval between 26,000 and 22,000 cal yr B.P. The deglaciation was characterized by a trend toward more arid conditions. During the middle Holocene (8000 -4000 cal yr B.P.), comparatively stable climatic conditions prevailed with increased aridity in the Coastal Range. The late Holocene (4000 -0 cal yr B.P.) was marked by more variable paleoclimates with generally more humid conditions. Variations of rainfall in mid-latitude Chile are most likely controlled by shifts of the latitudinal position of the Southern Westerlies. Compared to the Holocene, the southern westerly wind belt was located significantly farther north during the last glacial maximum. Less important variations of the latitudinal position of the Southern Westerlies also occurred on shorter time scales.

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“…The origin of both could be related to mobile polar highs (MPH) (Leroux, 1993), which may originate in the downward air motion in the polar latitudes, before moving equatorward. However, since the tropical poleward waves are the dominant variety, this implies that the MPH are only a minor component of the total variability in the global climate system, and not a key factor in climate as proposed by Leroux (1993).…”

Section: Zonal Analysismentioning

confidence: 99%

Interannual signals in length of day and atmospheric angular momentum

Río¹,

Gambis

Salstein

2000

Ann. Geophys.

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Abstract. Atmospheric angular momentum (AAM) and length of day (LOD) series are investigated for their characteristics on interannual time scales during the half-century period 1949 to 1998. During this epoch, the interannual variability in LOD can be separated naturally into three bands: a quasi-biennial, a triennialquadrennial and one at six-seven years. The atmosphere appears to excite the ®rst two bands, while it does not contribute to the last. Considering the quasi-biennial (QB) band alone, the atmosphere appears to excite most of its signal in LOD, but it arises from separatē uctuations with stratospheric and tropospheric origin. Thus, although close in frequency, stratospheric and tropospheric processes dier in their amplitude and phase variability. The time shift can be noted especially during the strong El NinÄ o events of 1982±83 and 1997± 98 when both processes have positive phase and thus combine to help produce particularly strong peak in AAM and LOD. In addition, we have recon®rmed the downward propagation in the stratosphere and upward propagation in the troposphere of AAM observed in earlier studies for other variables. In the triennialquadrennial (TQ) band, time-variable spectral analyses reveal that LOD and AAM contain strong variability, with periods shorter than four years before 1975 and longer thereafter. This signal originates mainly within the troposphere and propagates upwards from the lower to the higher layers of the troposphere. According to a zonal analysis, an equatorial poleward mode, strongly linked to the SOI, explains more than 60% of the total variability at these ranges. In addition, this study also indicates that an equatorward mode, originating within polar latitudes, explains, on average, more than 15% of the triennial-quadrennial oscillation (TQO) variability in AAM, and up to 30% at certain epochs. Finally, a six year period in LOD noted in earlier studies, as well as in lengthier series covering much of the century, is found to be absent in atmospheric excitations, and it is thus likely to arise from mantle/core interactions.

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The Mobile Polar High: a new concept explaining present mechanisms of meridional air-mass and energy exchanges and global propagation of palaeoclimatic changes

Cited by 73 publications

References 55 publications

Paleoclimate reconstruction along the Pole–Equator–Pole transect of the Americas (PEP 1)

Paleoclimate reconstruction along the Pole–Equator–Pole transect of the Americas (PEP 1)

High-Resolution Marine Record of Climatic Change in Mid-latitude Chile during the Last 28,000 Years Based on Terrigenous Sediment Parameters

Interannual signals in length of day and atmospheric angular momentum

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