Chapter 2 part 2 (lecture) Flashcards
The trade winds result from
the flow on the equatorial side of the subtropical highs and blow generally from ENE in the NH and from ESE in the SH
The trade wind inversion is strongest near
the center of the subtropical anticyclones, over cold currents, and cool waters upwelled by trade winds blowing away from the subtropical highs
The inversion affects
daily weather and air quality in the boundary layer in the subtropical and into the poleward region of the tropics, mainly through its influence on stability, clouds, and precipitation
The TWI is a stable layer, which means that its formation and maintenance are dependent on factors that lead to
increasing potential temperature with height
The most important factor that contributes to increasing the static stability is
strong divergence away from the subtropical ridge. the inversion weakens as divergence weakens to the west
………….. weakens the inversion
radiative processes
………. is necessary to maintaine the thermal trough
the seperation of the regions of maximum cloudiness and minimum pressure
The mean position of ITCZ is
15 N in boreal summer and 5 S in austral summer
Because of the land‐water contrasts, the ITCZ is not oriented
exactly zonally, but meanders north and south
The ITCZ takes its largest poleward excursions in
the summer hemisphere over large land masses
Because the NH has much more land than the SH
the ITCZ is closer to the poles in boreal summer than in austral summer
The trade‐wind trough occurs over the
open ocean areas of the north atlantic and over the northeast and north central pacific
The monsoon trough occurs near
large continental areas, and is prevalent in the western pacific and indian oceans
A region where the cross‐equatorial winds recurve from easterly to westerly is referred to as a
near equatorial buffer zone
Since the buffer zone is so close to the Equator, and Coriolis is
negligable in this region, terms such as cyclonic or anticyclonic have rather unclear meaning when applied to circulation in the buffer zone
In its mean annual position, the axis of the SPCZ stretches from
New Guinea east‐southeastwards to about 30oS, 120oW. In its northwestern sector, the SPCZ becomes more zonal and merges with the ITCZ, which extends westwards to the Indian Ocean (
The SPCZ lies in a region of
low‐level moisture convergence, between the predominantly northeasterly flow west of the eastern Pacific subtropical high and the cooler predominantly southeasterly flow from high latitudes
Thus, the SPCZ is characterized by
a band of low‐level convergence, cloudiness and precipitation lying from the west Pacific warm pool southeastwards towards French Polynesia
The SPCZ is a very important determinant of
South Pacific climate producing variability from interannual to multidecadal scales. Its location plays a key to climate anomalies and shifts
During El Niño episodes, tropical rains that are usually centered over
Indonesia shift eastward, influencing atmospheric wind patterns worldwide
Possible impacts include a shifting of
the jet stream, storm tracks and monsoons, producing unseasonable weather over many regions of the globe
El Nino events were found to be associated with
increased amounts of rain, while La Nina events were associated with less rainfall amounts
