Pacific typhoon season

Pacific typhoon season
Basin	Western North Pacific
Region	Northwest Pacific Ocean
Typical start	January 1
Typical end	December 31

Pacific typhoon season

The Pacific typhoon season denotes the annual cycle of tropical cyclone activity in the Northwest Pacific basin, affecting regions such as Philippines, Japan, Taiwan, China, and South Korea. It interacts with large-scale phenomena including the El Niño–Southern Oscillation, the Madden–Julian Oscillation, the monsoon trough, and the Pacific Decadal Oscillation, producing variability across climatological timescales. Agencies like the Japan Meteorological Agency, the Joint Typhoon Warning Center, the Philippine Atmospheric, Geophysical and Astronomical Services Administration, and the Shanghai Meteorological Bureau coordinate monitoring and advisories. Seasonal impacts involve storm surge, flooding, landslides, and disruption to infrastructure across archipelagos, peninsulas, and coastal megacities such as Manila, Tokyo, Shanghai, and Busan.

Overview

The Northwest Pacific basin is the most active tropical cyclone basin globally, where tropical cyclones commonly reach typhoon intensity before recurving toward the Aleutian Islands or impacting East Asia. Actions by organizations including the World Meteorological Organization and the United Nations Office for Disaster Risk Reduction shape international protocols for warnings, while national entities such as the Korea Meteorological Administration and the Hong Kong Observatory implement local response. The basin’s sea surface temperature patterns, influenced by the Kuroshio Current and the North Pacific Gyre, and atmospheric circulation like the Subtropical Ridge govern genesis locations and track orientations. Historical records preserved by the International Best Track Archive for Climate Stewardship support research on trends linked to global warming and anthropogenic forcing debates addressed in Intergovernmental Panel on Climate Change reports.

Seasonal patterns and climatology

Cyclone activity exhibits a pronounced seasonal cycle with peaks in late summer and early autumn, coinciding with maximum sea surface temperatures and reduced vertical wind shear near the Philippine Sea and the South China Sea. Teleconnections to El Niño and La Niña phases alter genesis frequency and tracks, modulating landfall statistics for nations like Vietnam, Hainan, Luzon, and Okinawa. Intraseasonal variability is driven by the Madden–Julian Oscillation and the Quasi-Biennial Oscillation, while decadal shifts relate to the Pacific Decadal Oscillation. Paleotempestology studies using proxies from the Ryukyu Islands and the Philippine archipelago contribute to long-term reconstructions linked to Little Ice Age era variability and modern observational datasets maintained by the National Oceanic and Atmospheric Administration.

Naming and classification

Names are assigned by the ESCAP/WMO Typhoon Committee from lists contributed by member territories including Japan, Malaysia, Singapore, Thailand, and North Korea. The Japan Meteorological Agency provides official intensity classifications (tropical depression, tropical storm, severe tropical storm, typhoon) while the Joint Typhoon Warning Center issues U.S. Department of Defense–oriented warnings and Saffir–Simpson comparisons used by entities like the United States Pacific Command. Retirement of names follows catastrophic impacts, a practice coordinated in meetings of the Typhoon Committee and documented alongside historical retirements such as Typhoon Haiyan (Yolanda), Typhoon Vera (Isewan), and Typhoon Tip.

Monitoring and forecasting

Monitoring combines satellite remote sensing from platforms like Himawari and Geostationary Operational Environmental Satellite series, reconnaissance data from NOAA flights in other basins, scatterometer winds from QuikSCAT heritage missions, and numerical weather prediction from centers including the European Centre for Medium-Range Weather Forecasts, the U.S. National Weather Service, and the Meteorological Service of New Zealand. Ensemble forecasting, data assimilation in models such as the Global Forecast System and the ECMWF IFS, and statistical–dynamical guidance integrate inputs from buoys of the TAO/TRITON array and ship observations recorded by the International Maritime Organization. Regional initiatives like the ASEAN Specialized Meteorological Centre and academic groups at institutions such as University of Hawaii at Manoa and Peking University advance forecasting research.

Impacts and preparedness

Typhoon impacts span human casualties, economic losses, and infrastructure damage across urban agglomerations including Ho Chi Minh City, Nagasaki, Guangzhou, and Zhanjiang. Preparedness measures involve evacuation protocols administered by national disaster agencies such as the National Disaster Risk Reduction and Management Council of the Philippines, floodplain management practiced by municipal governments in Osaka and Fukuoka, and international humanitarian responses coordinated by International Federation of Red Cross and Red Crescent Societies and United Nations Office for the Coordination of Humanitarian Affairs. Engineering standards for coastal defenses reference studies from the Asian Development Bank and infrastructure resilience projects financed by the World Bank. Insurance markets in centers like Tokyo and Hong Kong assess risk through exposure models developed with reinsurers such as Munich Re and Swiss Re.

Historical seasons and notable typhoons

Historical seasons include extreme events documented in the 1959 Pacific typhoon season with Typhoon Vera (Isewan), the 1979 Pacific typhoon season marked by Typhoon Tip, and recent catastrophic landfalls like Typhoon Haiyan (Yolanda) during the 2013 Pacific typhoon season. Other significant storms include Typhoon Nina (1975), Typhoon Nancy (1961), Typhoon Mireille (1991), Typhoon Fengshen (2008), Typhoon Mangkhut (2018), and Typhoon Hagibis (2019), each prompting changes in building codes, emergency management, and international cooperation exemplified by post-storm reconstruction funding through entities such as the Asian Infrastructure Investment Bank and the Japan International Cooperation Agency. Ongoing research by centers like the International Research Institute for Climate and Society examines attribution of extreme events to anthropogenic climate change.

Category:Tropical cyclones