<P> Most tropical cyclones form on the side of the subtropical ridge closer to the equator, then move poleward past the ridge axis before recurving into the main belt of the Westerlies . Areas west of Japan and Korea tend to experience much fewer September--November tropical cyclone impacts during El Niño and neutral years . During El Niño years, the break in the subtropical ridge tends to lie near 130 ° E, which would favor the Japanese archipelago . </P> <P> Within the Atlantic Ocean vertical wind shear is increased, which inhibits tropical cyclone genesis and intensification, by causing the westerly winds in the atmosphere to be stronger . The atmosphere over the Atlantic Ocean can also be drier and more stable during El Niño events, which can also inhibit tropical cyclone genesis and intensification . Within the Eastern Pacific basin: El Niño events contribute to decreased easterly vertical wind shear and favours above - normal hurricane activity . However, the impacts of the ENSO state in this region can vary and are strongly influenced by background climate patterns . The Western Pacific basin experiences a change in the location of where tropical cyclones form during El Niño events, without a major change in how many develop each year . As a result of this change Micronesia is more likely to be affected by several tropical cyclones, while China has a decreased risk of being affected by several tropical cyclones . A change in the location of where tropical cyclones form also occurs within the Southern Pacific Ocean between 135 ° E and 120 ° W, with tropical cyclones more likely to occur within the Southern Pacific basin than the Australian region . As a result of this change tropical cyclones are 50% less likely to make landfall on Queensland, while the risk of a tropical cyclone is elevated for island nations like Niue, French Polynesia, Tonga, Tuvalu and the Cook Islands . </P> <P> A study of climate records has shown that El Niño events in the equatorial Pacific are generally associated with a warm tropical North Atlantic in the following spring and summer . About half of El Niño events persist sufficiently into the spring months for the Western Hemisphere Warm Pool to become unusually large in summer . Occasionally, El Niño's effect on the Atlantic Walker circulation over South America strengthens the easterly trade winds in the western equatorial Atlantic region . As a result, an unusual cooling may occur in the eastern equatorial Atlantic in spring and summer following El Niño peaks in winter . Cases of El Niño - type events in both oceans simultaneously have been linked to severe famines related to the extended failure of monsoon rains . </P> <P> Many ENSO linkages exist in the high southern latitudes around Antarctica . Specifically, El Niño conditions result in high - pressure anomalies over the Amundsen and Bellingshausen Seas, causing reduced sea ice and increased poleward heat fluxes in these sectors, as well as the Ross Sea . The Weddell Sea, conversely, tends to become colder with more sea ice during El Niño . The exact opposite heating and atmospheric pressure anomalies occur during La Niña . This pattern of variability is known as the Antarctic dipole mode, although the Antarctic response to ENSO forcing is not ubiquitous . </P>

When an el nino is occurring which of the following is true