Tropical cyclones over the western north Pacific since the mid-nineteenth century

The Pacific Meridional Mode and the Occurrence of Tropical 1 Cyclones in the Western North Pacific

30 This study investigates the association between the Pacific Meridional Mode (PMM) 31 and tropical cyclone (TC) activity in the western North Pacific (WNP). It is found that 32 the positive PMM phase favors the occurrence of TCs in the WNP while the negative 33 PMM phase inhibits the occurrence of TCs there. Observed relationships are 34 consistent with those from a long-term preindustrial co...

What Percentage of Western North Pacific Tropical Cyclones Form within the Monsoon Trough?

It is frequently stated that 70%–80% of western North Pacific tropical cyclones form ‘‘within the monsoon trough,’’ but without an objective definition of the term. Several definitions are tested here. When the monsoon trough (MT) is defined as the contiguous region where long-term (1988–2010) mean July– November 850-hPa relative vorticity is positive, 73% of all July–November tropical cyclones...

Effect of ENSO and the MJO on Western North Pacific Tropical Cyclones

Prior work has suggested that Rossby wave accumulation in the lower troposphere may be an important mechanism for the development of synoptic-scale disturbances in the western north Pacific in northern summer. This work examines the intraseasonal and interannual variability of wave accumulation by computing the barotropic wave activity flux divergence at 850 hPa for different phases of the Madd...

Are Tropical Cyclones Less Effectively Formed by Easterly Waves in the Western North Pacific than in the North Atlantic?

Variability and decline in the number of severe tropical cyclones making land-fall over eastern Australia since the late nineteenth century

Recent studies have raised concerns that tropical cyclones (TCs), particularly severe TCs, have become more frequent in many places in response to global warming. Other studies discuss errors in TC data that can cause large inaccuracies in some of the observed trends. Additional studies conclude that TCs are likely to become more intense in the future in response to global warming, while region...