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Typhoon Sepat (2007)
Typhoon Sepat, known in the Philippines as Super Typhoon Egay, was the eighth named tropical storm and the strongest tropical cyclone of the 2007 Pacific typhoon season, that affected the Philippines and made landfall in Taiwan and Fujian in mid August 2007. Sepat originated on August 11 via a low-circulation center SE of Naha, Okinawa, and was named by the Japan Meteorological Agency as Sepat on August 12 and Egay in the Philippines by PAGASA as it entered the PAR. Sepat underwent an explosive intensification on the night of August 13, reaching peak intensity at Category 5-equivalent super typhoon intensity the following morning. The storm maintained its strength for 2 days, until it underwent an eyewall replacement cycle, just before he storm makes landfall in Taiwan on August 17 (+21:00 UTC) as a Category 3-equivalent typhoon. After crossing the Taiwanese strait, Sepat; already weakening into Category 1 status due to unfavorable conditions, made a second landfall in China o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philippines
The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a total area of roughly 300,000 square kilometers, which are broadly categorized in Island groups of the Philippines, three main geographical divisions from north to south: Luzon, Visayas, and Mindanao. With a population of over 110 million, it is the world's List of countries and dependencies by population, twelfth-most-populous country. The Philippines is bounded by the South China Sea to the west, the Philippine Sea to the east, and the Celebes Sea to the south. It shares maritime borders with Taiwan to the north, Japan to the northeast, Palau to the east and southeast, Indonesia to the south, Malaysia to the southwest, Vietnam to the west, and China to the northwest. It has Ethnic groups in the Philippines, diverse ethnicities and Culture o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Dollar
The United States dollar (Currency symbol, symbol: Dollar sign, $; ISO 4217, currency code: USD) is the official currency of the United States and International use of the U.S. dollar, several other countries. The Coinage Act of 1792 introduced the U.S. dollar at par with the Spanish dollar, Spanish silver dollar, divided it into 100 cent (currency), cents, and authorized the Mint (facility), minting of coins denominated in dollars and cents. U.S. banknotes are issued in the form of Federal Reserve Notes, popularly called greenbacks due to their predominantly green color. The U.S. dollar was originally defined under a bimetallism, bimetallic standard of (0.7734375 troy ounces) fine silver or, from Coinage Act of 1834, 1834, fine gold, or $20.67 per troy ounce. The Gold Standard Act of 1900 linked the dollar solely to gold. From 1934, its equivalence to gold was revised to $35 per troy ounce. In 1971 all links to gold were repealed. The U.S. dollar became an important intern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Convection
Atmospheric convection is the vertical transport of heat and moisture in the atmosphere. It occurs when warmer, less dense air rises, while cooler, denser air sinks. This process is driven by parcel-environment instability, meaning that a "parcel" of air is warmer and less dense than the surrounding environment at the same altitude. This difference in temperature and density (and sometimes humidity) causes the parcel to rise, a process known as buoyancy. This rising air, along with the compensating sinking air, leads to mixing, which in turn expands the height of the planetary boundary layer (PBL), the lowest part of the atmosphere directly influenced by the Earth's surface. This expansion contributes to increased winds, cumulus cloud development, and decreased surface dew points (the temperature below which condensation occurs). Convection plays a crucial role in weather patterns, influencing cloud formation, wind, and the development of thunderstorms, which can be associa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dvorak Technique
The Dvorak technique (developed between 1969 and 1984 by Vernon Dvorak) is a widely used system to estimate tropical cyclone intensity (which includes tropical depression, tropical storm, and hurricane/typhoon/intense tropical cyclone intensities) based solely on visible and infrared Weather satellite, satellite images. Within the Dvorak satellite strength estimate for tropical cyclones, there are several Pattern recognition, visual patterns that a cyclone may take on which define the upper and lower bounds on its intensity. The primary patterns used are curved rainband, band pattern (T1.0-T4.5), Wind shear#Effects on tropical cyclones, shear pattern (T1.5–T3.5), central dense overcast (CDO) pattern (T2.5–T5.0), central cold cover (CCC) pattern, banding eye pattern (T4.0–T4.5), and Eye (cyclone), eye pattern (T4.5–T8.0). Both the central dense overcast and embedded eye pattern use the size of the CDO. The CDO pattern intensities start at T2.5, equivalent to minimal trop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Okinawa Prefecture
is the southernmost and westernmost prefecture of Japan. It consists of three main island groups—the Okinawa Islands, the Sakishima Islands, and the Daitō Islands—spread across a maritime zone approximately 1,000 kilometers east to west and 400 kilometers north to south. Despite a modest land area of 2,281 km² (880 sq mi), Okinawa’s territorial extent over surrounding seas makes its total area nearly half the combined size of Honshu, Shikoku, and Kyushu. Of its 160 Island, islands, 49 are inhabited. The largest and most populous island is Okinawa Island, which hosts the capital city, Naha, as well as major urban centers such as Okinawa (city), Okinawa, Uruma, and Urasoe, Okinawa, Urasoe. The prefecture has a subtropical climate, characterized by warm temperatures and high rainfall throughout the year. People from the Ryukyu Islands, Nansei Islands, including Okinawa Island, Okinawa, the Sakishima Islands, and parts of Kagoshima Prefecture, are often collectively referred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ridge (meteorology)
In meteorology a ridge or barometric ridge is an elongated area of relatively high atmospheric pressure compared to the surrounding environment, without being a closed circulation. It is associated with an area of maximum anticyclonic curvature of wind flow. The ridge originates in the center of an anticyclone and sandwiched between two low-pressure areas, and the locus of the maximum curvature is called the ''ridge line''. This phenomenon is the opposite of a trough. Description Ridges can be represented in two ways: * On surface weather maps, the pressure isobars form contours where the maximum pressure is found along the axis of the ridge. * In upper-air maps, geopotential height isohypses form similar contours where the maximum defines the ridge. Related weather Given the direction of the winds around an anticyclonic circulation and the fact that weather systems move from west to east: *ahead of an upper-ridge, the airflow that comes from the polar regions and bri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropical Cyclone Formation Alert
A Tropical Cyclone Formation Alert (TCFA) is a bulletin released by the U.S. Navy-operated Joint Typhoon Warning Center in Honolulu, Hawaii or the Fleet Weather Center in Norfolk, Virginia, warning of the possibility of a tropical cyclone forming from a tropical disturbance that has been monitored. Such alerts are generally always issued when it is fairly certain that a tropical cyclone will form and are not always released before cyclogenesis, particularly if the cyclone appears suddenly. The TCFA consists of several different checks that are performed by the on-duty meteorologist of the system and its surroundings. If the condition being checked is met, a certain number of points are given to the system. Parts of the TCFA Section 1 The first section of the TCFA contains information on the area of the alert as well as the estimated center of the circulation. The estimated maximum sustained winds are provided as well. Section 2 The second section generally contains more specif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joint Typhoon Warning Center
The Joint Typhoon Warning Center (JTWC) is a joint United States Navy – United States Air Force command in Pearl Harbor, Hawaii. The JTWC is responsible for the issuing of tropical cyclone warnings in the North-West Pacific Ocean, South Pacific Ocean, and Indian Ocean for all branches of the U.S. Department of Defense and other U.S. government agencies. Their warnings are intended primarily for the protection of U.S. military ships and aircraft, as well as military installations jointly operated with other countries around the world. Its U.S. Navy components are aligned with the Naval Meteorology and Oceanography Command. History The origins of the Joint Typhoon Warning Center (JTWC) can be traced back to June 1945, when the Fleet Weather Center/Typhoon Tracking Center was established on the island of Guam, after multiple typhoons, including Typhoon Cobra of December 1944 and Typhoon Connie in June 1945, had caused a significant loss of men and ships. At this time th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticyclone
A high-pressure area, high, or anticyclone, is an area near the surface of a planet where the atmospheric pressure is greater than the pressure in the surrounding regions. Highs are middle-scale meteorological features that result from interplays between the relatively larger-scale dynamics of an entire planet's atmospheric circulation. The strongest high-pressure areas result from masses of cold air which spread out from polar regions into cool neighboring regions. These highs weaken once they extend out over warmer bodies of water. Weaker—but more frequently occurring—are high-pressure areas caused by atmospheric subsidence: Air becomes cool enough to precipitate out its water vapor, and large masses of cooler, drier air descend from above. Within high-pressure areas, winds flow from where the pressure is highest, at the center of the area, towards the periphery where the pressure is lower. However, the direction is not straight from the center outwards, but curved du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outflow (meteorology)
Outflow, in meteorology, is air that flows outwards from a storm system. It is associated with ridging, or anticyclone, anticyclonic flow. In the low levels of the troposphere, outflow radiates from thunderstorms in the form of a wedge of rain-cooled air, which is visible as a thin rope-like cloud on weather satellite imagery or a fine line on weather radar imagery. For observers on the ground, a thunderstorm outflow boundary often approaches in otherwise clear skies as a low, thick cloud that brings with it a gust front. Low-level outflow boundaries can disrupt the center of small tropical cyclones. However, outflow aloft is essential for the strengthening of a tropical cyclone. If this outflow is restricted or undercut, the tropical cyclone weakens. If two tropical cyclones are close, the upper-level outflow from the upwind system can limit the development of the other system. Thunderstorms For thunderstorms, outflow tends to indicate the development of a system. Large quan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wind Shear
Wind shear (; also written windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. Vertical wind shear is a change in wind speed or direction with a change in altitude. Horizontal wind shear is a change in wind speed with a change in lateral position for a given altitude. Wind shear is a microscale meteorological phenomenon occurring over a very small distance, but it can be associated with mesoscale or synoptic scale weather features such as squall lines and cold fronts. It is commonly observed near microbursts and downbursts caused by thunderstorms, fronts, areas of locally higher low-level winds referred to as low-level jets, near mountains, radiation inversions that occur due to clear skies and calm winds, buildings, wind turbines, and sailboats. Wind shear has significant effects on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Divergence
In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the rate that the vector field alters the volume in an infinitesimal neighborhood of each point. (In 2D this "volume" refers to area.) More precisely, the divergence at a point is the rate that the flow of the vector field modifies a volume about the point ''in the limit'', as a small volume shrinks down to the point. As an example, consider air as it is heated or cooled. The velocity of the air at each point defines a vector field. While air is heated in a region, it expands in all directions, and thus the velocity field points outward from that region. The divergence of the velocity field in that region would thus have a positive value. While the air is cooled and thus contracting, the divergence of the velocity has a negative value. Physical interpretation of divergence In physical terms, the divergence of a vector field is the extent to which the vector fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
