Accumulated cyclone energy (ACE) is a measure used by the National Oceanic and Atmospheric Administration (NOAA) to express the activity of individual tropical cyclones and entire tropical cyclone seasons, particularly the Atlantic hurricane seasons. The National Oceanic and Atmospheric Administration ( NOAA) is a scientific agency within the United States Department of Commerce focused on the conditions of the A tropical cyclone is a storm system characterized by a low pressure center and numerous Thunderstorms that produce strong winds and Flooding It uses an approximation of the energy used by a tropical system over its lifetime and is calculated every six-hour period. The ACE of a season is the sum of the ACEs for each storm and takes into account the number, strength, and duration of all the tropical storms in the season. A tropical cyclone is a storm system characterized by a low pressure center and numerous Thunderstorms that produce strong winds and Flooding [1]
Contents |
Calculation
The ACE is calculated by summing the squares of the estimated maximum sustained velocity of every active tropical storm (wind speed 35 knots or higher), at six-hour intervals. The numbers are usually divided by 10,000 to make them more manageable. The unit of ACE is 104 kt2, and for use as an index the unit is assumed. If any storms of a season happen to cross years, the storm's ACE counts for the previous year. [2]
where vmax is estimated sustained wind speed in knots.
Kinetic energy is proportional to the square of velocity, and by adding together the energy per some interval of time, the accumulated energy is found. The kinetic energy of an object is the extra Energy which it possesses due to its motion As the duration of a storm increases, more values are summed and the ACE also increases such that longer-duration storms may accumulate a larger ACE than more-powerful storms of lesser duration. Although ACE is a value proportional to the energy of the system, it is not a direct calculation of energy (the mass of the moved air and therefore the size of the storm would show up in a real energy calculation).
A related quantity is hurricane destruction potential (HDP), which is ACE but only calculated for the time where the system is a hurricane. [1]
Climatology
Measured over the period 1951-2005 for the Atlantic basin:
- Median annual index: 89. In Probability theory and Statistics, a median is described as the number separating the higher half of a sample a population or a Probability distribution 5
- Mean annual index: 102. In Mathematics and Statistics, the arithmetic Mean (or simply the mean) of a list of numbers is the sum of all the members of the list divided 3
A season's ACE is used to categorize the hurricane season by its activity. NOAA categorisation system[3] divides them into:
- Above-normal season: An ACE value above 103 (115% of the current median), provided at least two of the following three parameters exceed the long-term average: number of tropical storms (10), hurricanes (6), and major hurricanes (2).
- Near-normal season: neither above-normal nor below normal
- Below-normal season: An ACE value below 66 (74% of the current median)
Individual storms
The highest ever ACE estimated for a single storm in the Atlantic is 73. 6, for Hurricane San Ciriaco in 1899. 1899 Hurricane San Ciriaco, also known as the 1899 Puerto Rico Hurricane, was an intense and long-lived Atlantic Cape Verde-type hurricane which crossed Puerto TemplateHurricane season single. -->The 1899 Atlantic hurricane season ran through the summer and the first half of fall in 1899 This single storm had an ACE higher than many whole Atlantic storm seasons. Other Atlantic storms with high ACEs include Hurricane Ivan in 2004, with an ACE of 70. Hurricane Ivan was the strongest hurricane of the 2004 Atlantic hurricane season. TemplateHurricane season single. -->The 2004 Atlantic hurricane season officially began on June 1 2004 and lasted until November 30 2004 4, and Hurricane Donna in 1960, with an ACE of 64. Hurricane Donna in the 1960 Atlantic hurricane season was a Cape Verde-type hurricane which moved across the Leeward Islands, Puerto Rico TemplateHurricane season single. -->The 1960 Atlantic hurricane season officially began on June 15, 1960, and lasted until 6.
ACE index for hurricane seasons 1950-2006
The scale on the left represents the total Accumulated Cyclone Energy Index for the Atlantic Season, and the scale on the right the ACE/Storm average for that season.
Atlantic hurricane seasons 1950-2007 by ACE index
The term hyperactive is used by Goldenberg et al. (2001) [4][5] based on a different weighting algorithm which places more weight on major hurricanes, but typically equating to an ACE of about 153 (171% of the current median).
-
Key • ACE Accumulated cyclone energy • TS Number of tropical storms • HR Number of hurricanes (S-S Category 1 – 5) • MH Number of major hurricanes (Category 3 – 5) (Fields with record values are in bold)
For definitions of the terms "above", "near", and "below" normal, see the Climatology section above. The Saffir-Simpson Hurricane Scale is a classification used for most Western Hemisphere Tropical cyclones that exceed the intensities of Tropical depressions
| Season | ACE | TS | HR | MH | Classification |
|---|---|---|---|---|---|
| 2005 Atlantic hurricane season | 248 | 27 | 15 | 7 | Above normal (hyperactive) |
| 1950 Atlantic hurricane season | 243 | 13 | 11 | 8 | Above normal (hyperactive) |
| 1995 Atlantic hurricane season | 228 | 19 | 11 | 5 | Above normal (hyperactive) |
| 2004 Atlantic hurricane season | 225 | 14 | 9 | 6 | Above normal (hyperactive) |
| 1961 Atlantic hurricane season | 205 | 11 | 8 | 7 | Above normal (hyperactive) |
| 1955 Atlantic hurricane season | 199 | 12 | 9 | 6 | Above normal (hyperactive) |
| 1998 Atlantic hurricane season | 182 | 14 | 10 | 3 | Above normal (hyperactive) |
| 1999 Atlantic hurricane season | 177 | 12 | 8 | 5 | Above normal (hyperactive) |
| 2003 Atlantic hurricane season | 175 | 16 | 7 | 3 | Above normal (hyperactive) |
| 1964 Atlantic hurricane season | 170 | 12 | 6 | 6 | Above normal (hyperactive) |
| 1996 Atlantic hurricane season | 166 | 13 | 9 | 6 | Above normal (hyperactive) |
| 1969 Atlantic hurricane season | 158 | 17 | 12 | 5 | Above normal (hyperactive) |
| 1980 Atlantic hurricane season | 147 | 11 | 9 | 2 | Above normal |
| 1966 Atlantic hurricane season | 145 | 11 | 7 | 3 | Above normal |
| 1951 Atlantic hurricane season | 137 | 10 | 8 | 5 | Above normal |
| 1989 Atlantic hurricane season | 135 | 11 | 7 | 2 | Above normal |
| 1967 Atlantic hurricane season | 122 | 8 | 6 | 1 | Near normal |
| 1958 Atlantic hurricane season | 121 | 10 | 7 | 5 | Above normal |
| 1963 Atlantic hurricane season | 118 | 9 | 7 | 2 | Near normal |
| 2000 Atlantic hurricane season | 116 | 14 | 8 | 3 | Above normal |
| 1954 Atlantic hurricane season | 113 | 11 | 8 | 2 | Above normal |
| 2001 Atlantic hurricane season | 106 | 15 | 9 | 4 | Above normal |
| 1953 Atlantic hurricane season | 104 | 14 | 6 | 4 | Above normal |
| 1988 Atlantic hurricane season | 103 | 12 | 5 | 3 | Above normal |
| --- (Mean 1950 - 2005: 102. The 1950 Atlantic hurricane season officially began on June 16, 1950, and lasted until October 31, 1950. TemplateHurricane season single. -->The 1995 Atlantic hurricane season officially began on June 1 1995 and lasted until November 30 1995 TemplateHurricane season single. -->The 2004 Atlantic hurricane season officially began on June 1 2004 and lasted until November 30 2004 TemplateHurricane season single. -->The 1961 Atlantic hurricane season officially began on June 15, 1961, and lasted until The 1955 Atlantic hurricane season officially began on June 15, 1955, and lasted until November 15, 1955. TemplateHurricane season single. -->The 1998 Atlantic hurricane season officially began on June 1 1998 and lasted until November 30 1998 TemplateHurricane season single. -->The 1999 Atlantic hurricane season officially began on June 1 1999 and lasted until November 30 1999 TemplateHurricane season single. -->The 1964 Atlantic hurricane season officially began on June 15, 1964, and lasted until TemplateHurricane season single. -->The 1996 Atlantic hurricane season officially began on June 1 1996 and lasted until November 30 1996 TemplateHurricane season single. -->The 1969 Atlantic hurricane season officially began on June 1, 1969, and lasted until TemplateHurricane season single. -->The 1980 Atlantic hurricane season officially began on June 1, 1980, and lasted until TemplateHurricane season single. -->The 1966 Atlantic hurricane season officially began on June 1, 1966, and lasted until The 1951 Atlantic hurricane season officially began on June 15, 1951, and lasted until November 15, 1951. TemplateHurricane season single. -->The 1989 Atlantic hurricane season officially began on June 1, 1989, and lasted until TemplateHurricane season single. -->The 1967 Atlantic hurricane season officially began on June 1, 1967, and lasted until TemplateHurricane season single. -->The 1958 Atlantic hurricane season officially began on June 15, 1958, and lasted until TemplateHurricane season single. -->The 1963 Atlantic hurricane season officially began on June 15, 1963, and lasted until TemplateHurricane season single. -->The 2000 Atlantic hurricane season was a fairly active season with 15 named storms 8 hurricanes and a subtropical The 1954 Atlantic hurricane season officially began on June 15, 1954, and lasted until November 15, 1954. The 2001 Atlantic hurricane season was a fairly active Atlantic hurricane season that produced 17 Tropical cyclones, 15 named storms 9 hurricanes and The 1953 Atlantic hurricane season officially began on June 15, 1953, and lasted until November 15, 1953. The 1988 Atlantic hurricane season was a moderately active season that proved costly and deadly with 15 Tropical cyclones directly affecting land 3) --- | |||||
| 1971 Atlantic hurricane season | 97 | 13 | 6 | 1 | Near normal |
| 1981 Atlantic hurricane season | 93 | 11 | 7 | 3 | Near normal |
| 1979 Atlantic hurricane season | 91 | 8 | 5 | 2 | Near normal |
| 1990 Atlantic hurricane season | 91 | 14 | 8 | 1 | Near normal |
| --- (Median 1950 - 2005: 89. TemplateHurricane season single. -->The 1971 Atlantic hurricane season officially began on June 1, 1971, and lasted until TemplateHurricane season single. -->The 1981 Atlantic hurricane season officially began on June 1 1981 and lasted until November 30 1981 TemplateHurricane season single. -->The 1979 Atlantic hurricane season officially began on June 1, 1979, and lasted until TemplateHurricane season single. -->The 1990 Atlantic hurricane season officially began on June 1 1990 and lasted until November 30 1990 5) --- | |||||
| 1960 Atlantic hurricane season | 88 | 7 | 4 | 2 | Near normal |
| 1985 Atlantic hurricane season | 88 | 11 | 7 | 3 | Near normal |
| 1952 Atlantic hurricane season | 87 | 7 | 6 | 3 | Near normal |
| 1965 Atlantic hurricane season | 84 | 6 | 4 | 1 | Near normal |
| 1957 Atlantic hurricane season | 84 | 8 | 3 | 2 | Near normal |
| 1976 Atlantic hurricane season | 81 | 8 | 6 | 2 | Near normal |
| 2006 Atlantic hurricane season | 79 | 10 | 5 | 2 | Near normal |
| 1959 Atlantic hurricane season | 77 | 11 | 7 | 2 | Near normal |
| 1992 Atlantic hurricane season | 75 | 6 | 4 | 1 | Near normal |
| 1975 Atlantic hurricane season | 73 | 8 | 6 | 3 | Near normal |
| 2007 Atlantic hurricane season | 72 | 15 | 6 | 2 | Near normal |
| 1984 Atlantic hurricane season | 71 | 12 | 5 | 1 | Near normal |
| 1978 Atlantic hurricane season | 62 | 11 | 5 | 2 | Below normal |
| 1974 Atlantic hurricane season | 61 | 7 | 4 | 2 | Below normal |
| 1956 Atlantic hurricane season | 54 | 8 | 4 | 2 | Below normal |
| 1973 Atlantic hurricane season | 43 | 7 | 4 | 1 | Below normal |
| 1997 Atlantic hurricane season | 40 | 7 | 3 | 1 | Below normal |
| 1993 Atlantic hurricane season | 39 | 8 | 4 | 1 | Below normal |
| 1962 Atlantic hurricane season | 36 | 5 | 3 | 1 | Below normal |
| 1986 Atlantic hurricane season | 36 | 6 | 4 | 0 | Below normal |
| 1968 Atlantic hurricane season | 35 | 7 | 4 | 0 | Below normal |
| 1970 Atlantic hurricane season | 34 | 10 | 5 | 2 | Below normal |
| 1987 Atlantic hurricane season | 34 | 7 | 3 | 1 | Below normal |
| 1991 Atlantic hurricane season | 34 | 8 | 4 | 2 | Below normal |
| 1994 Atlantic hurricane season | 32 | 7 | 3 | 0 | Below normal |
| 1982 Atlantic hurricane season | 29 | 5 | 2 | 1 | Below normal |
| 1972 Atlantic hurricane season | 28 | 4 | 3 | 0 | Below normal |
| 1977 Atlantic hurricane season | 25 | 6 | 5 | 1 | Below normal |
| 1983 Atlantic hurricane season | 17 | 4 | 3 | 1 | Below normal |
East Pacific ACE
Accumulated Cyclone Energy is also used in the eastern and central Pacific Ocean. TemplateHurricane season single. -->The 1960 Atlantic hurricane season officially began on June 15, 1960, and lasted until TemplateHurricane season single. -->The 1985 Atlantic hurricane season officially began on June 1, 1985, and lasted until The 1952 Atlantic hurricane season officially began on June 15, 1952, and lasted until November 15, 1952. TemplateHurricane season single. -->The 1965 Atlantic hurricane season officially began on June 1, 1965, and lasted until TemplateHurricane season single. -->The 1957 Atlantic hurricane season officially began on June 15, 1957, and lasted until TemplateHurricane season single. -->The 1976 Atlantic hurricane season officially began on June 1, 1976, and lasted until TemplateHurricane season single. -->The 1959 Atlantic hurricane season officially began on June 15, 1959, and lasted until TemplateHurricane season single. -->The 1992 Atlantic hurricane season officially began on June 1, 1992, and lasted until TemplateHurricane season single. -->The 1975 Atlantic hurricane season officially began on June 1, 1975, and lasted until The 2007 Atlantic hurricane season was an active Atlantic hurricane season that produced 17 Tropical cyclones It officially started on June 1 and ended on TemplateHurricane season single. -->The 1984 Atlantic hurricane season officially began on June 1, 1984, and lasted until TemplateHurricane season single. -->The 1978 Atlantic hurricane season officially began on June 1, 1978, and lasted until TemplateHurricane season single. -->The 1974 Atlantic hurricane season officially began on June 1, 1974, and lasted until TemplateHurricane season single. -->The 1956 Atlantic hurricane season officially began on June 15, 1956, and lasted until The 1973 Atlantic hurricane season was the first season to use the Saffir-Simpson Hurricane Scale. TemplateHurricane season single. -->The 1997 Atlantic hurricane season officially began on June 1, 1997, and lasted until TemplateHurricane season single. -->The 1993 Atlantic hurricane season was a period in the annual formation of tropical cyclones TemplateHurricane season single. -->The 1962 Atlantic hurricane season officially began on June 15, 1962, and lasted until TemplateHurricane season single. -->The 1986 Atlantic hurricane season officially began on June 1, 1986, and lasted until TemplateHurricane season single. -->The 1968 Atlantic hurricane season officially began on June 1, 1968, and lasted until The 1970 Atlantic hurricane season officially began on June 1, 1970, and lasted until November 30, 1970. The 1987 Atlantic hurricane season was depicted as an average hurricane season that was limited by an ongoing El Niño. TemplateHurricane season single. -->The 1991 Atlantic hurricane season officially began on June 1, 1991, and lasted until TemplateHurricane season single. -->The 1994 Atlantic hurricane season officially began on June 1 1994 and lasted until November 30 1994 TemplateHurricane season single. -->The 1982 Atlantic hurricane season officially began on June 1, 1982, and lasted until TemplateHurricane season single. -->The 1972 Atlantic hurricane season officially began on June 1, 1972, and lasted until TemplateHurricane season single. -->The 1977 Atlantic hurricane season officially began on June 1, 1977, and lasted until TemplateHurricane season single. -->The 1983 Atlantic hurricane season was the least active Atlantic hurricane season in 53 years Data on ACE is considered reliable starting with the 1971 season. The 1971 Pacific hurricane season began on May 15, 1971 in the east Pacific, and on June 1, 1971 in the central Pacific The season with the highest ACE since 1971 is the 1992 season. The 1992 Pacific hurricane season was the most active Pacific season on record The 1977 season has the lowest ACE. The 1977 Pacific hurricane season officially started May 15, 1977 in the eastern Pacific and June 1, 1977 in the central Pacific and lasted The most recent above-normal season is the 2006 season, the most recent near-normal season is the 2002 season, and the most recent below normal season is the 2007 season. The 2002 Pacific hurricane season was an event in tropical cyclone meteorology The 2007 Pacific hurricane season was an event in the annual cycle of Tropical cyclone formation [6] The 35 year median 1971-2005 is 115 x 104kt2 (100 in the EPAC zone east of 140°W, 13 in the CPAC zone); the mean is 130 (112 + 18).
The (unofficial) categorisation of seasons for this table is based mutatis mutandis on that used in the Atlantic basin:
- Above-normal season: An ACE value above 135 (117% of the median), provided at least two of the following three parameters exceed the long-term average: number of tropical storms (16), hurricanes (9), and major hurricanes (4).
- Near-normal season: neither above-normal nor below normal
- Below-normal season: An ACE value below 86 (75% of the median)
Calculations from Eastern North Pacific Tracks File at NHC[1]
West Pacific ACE
ACE is also used in the western Pacific. The 1992 Pacific hurricane season was the most active Pacific season on record The 1990 Pacific hurricane season officially started on May 15, 1990 in the eastern Pacific and on June 1, 1990 in the central Pacific and The 1978 Pacific hurricane season officially began May 15, 1978, in the eastern Pacific June 1, 1978 in the central Pacific and officially The 1983 Pacific hurricane season officially started May 15, 1983 in the eastern Pacific and June 1, 1983 in the central Pacific and lasted The 1993 Pacific hurricane season officially started May 15, 1993 in the eastern Pacific and June 1, 1993 in the central Pacific and lasted The 1984 Pacific hurricane season officially started May 15, 1984 in the eastern Pacific and June 1, 1984 in the central Pacific and lasted The 1985 Pacific hurricane season was an ongoing event in Tropical cyclone meteorology The 1994 Pacific hurricane season officially started on May 15 1994 in the eastern Pacific and on June 1 1994 in the central Pacific and lasted until November 30 1994 The 1991 Pacific hurricane season officially started on May 15, 1991 in the eastern Pacific and on June 1, 1991 in the central Pacific and The 1997 Pacific hurricane season was an annual event in Tropical cyclone Meteorology. The 1982 Pacific hurricane season officially started May 15 1982 in the eastern Pacific and June 1 1982 in the central Pacific and lasted until November 30 1982 The 1971 Pacific hurricane season began on May 15, 1971 in the east Pacific, and on June 1, 1971 in the central Pacific The 1972 Pacific hurricane season began on May 15, 1972 in the east Pacific, and on June 1, 1972 in the central Pacific The 1998 Pacific hurricane season was a moderately active Pacific hurricane season with seven Tropical cyclones directly affecting land The 1987 Pacific hurricane season officially started May 15, 1987 in the eastern Pacific and June 1, 1987 in the central Pacific and lasted The 2002 Pacific hurricane season was an event in tropical cyclone meteorology The 1976 Pacific hurricane season was an ongoing event in tropical cyclone formation The 1973 Pacific hurricane season officially started May 15, 1973 in the eastern Pacific and June 1, 1973 in the central Pacific and lasted The 1988 Pacific hurricane season was a Pacific hurricane season that saw a below-average amount of Tropical cyclones form and that had only one landfalling The 1975 Pacific hurricane season officially started May 15, 1975 in the eastern Pacific and June 1, 1975 in the central Pacific and lasted The 1989 Pacific hurricane season officially started May 15 1989 in the Eastern Pacific and June 1 1989 in the Central Pacific and lasted until November 30 1989 The 1986 Pacific hurricane season officially started May 15, 1986 in the eastern Pacific and June 1, 1986 in the central Pacific and lasted The 1995 Pacific hurricane season was the least active Pacific hurricane season since 1979. The 2005 Pacific hurricane season officially began on May 15, 2005 in the eastern Pacific and on June 1 2005 in the central Pacific and lasted The 2000 Pacific hurricane season was an ongoing event in Tropical cyclone Meteorology. The 1974 Pacific hurricane season officially started May 15, 1974 in the eastern Pacific and June 1, 1974 in the central Pacific and lasted The 1999 Pacific hurricane season officially started on May 15, 1999 in the eastern Pacific and on June 1, 1999 in the central Pacific and The 2001 Pacific hurricane season officially started on May 15, 2001 in the eastern Pacific and on June 1, 2001 in the central Pacific and The 1980 Pacific hurricane season officially started May 15, 1980 in the eastern Pacific and June 1, 1980 in the central Pacific and lasted The 1981 Pacific hurricane season officially started May 15, 1981 in the eastern Pacific and June 1, 1981 in the central Pacific and lasted The 2004 Pacific hurricane season officially started on May 15 2004 in the eastern Pacific and on June 1 2004 in the central Pacific and lasted The 1979 Pacific hurricane season officially started May 15, 1979 in the eastern Pacific and June 1, 1979 in the central Pacific and lasted The 2003 Pacific hurricane season saw an unusually large number of Tropical cyclones affect Mexico. The 1996 Pacific hurricane season was an ongoing event in tropical cyclone formation and the second least active Pacific hurricane season in recorded history behind The 2007 Pacific hurricane season was an event in the annual cycle of Tropical cyclone formation The 1977 Pacific hurricane season officially started May 15, 1977 in the eastern Pacific and June 1, 1977 in the central Pacific and lasted 2004 had an ACE of 464 104 kt2 for the NW Pacific. This was the third highest since 1965, after 1992 and 1997. The 40 year norm (1965-2004) is 305 +/-99 104 kt2.
See also
References
- ^ a b Bell, Gerald D., Halpert, Michael S., Schnell, Russell C., Higgins, R. Wayne, Lawrimore, Jay, Kousky, Vernon E., Tinker, Richard, Thiaw, Wasila, Chelliah, Muthuvel, Artusa, Anthony. Climate Assessment for 1999. Bulletin of the American Meteorological Society 2000 81: 1328-1328
- ^ Last advisory for T.S. Zeta 2005
- ^ Climate Prediction Center - Background Information: The North Atlantic Hurricane Season
- ^ The Recent Increase in Atlantic Hurricane Activity: Causes and Implications
- ^ Supplementary material. The following is list of Atlantic hurricane seasons. The Atlantic hurricane season is the period in a year when hurricanes usually form in the Atlantic Ocean The Recent Increase in Atlantic Hurricane Activity: Causes and Implications
- ^ East North Pacific ACE (through 30 Nov. 2005)
External links
- NOAA ACE by year from 1851
- National Climatic Data Center - Atlantic Basin 2004 Accumulated Cyclone Energy (ACE) Index
- National Climatic Data Center - Atlantic Basin 2005 Accumulated Cyclone Energy (ACE) Index
- 2004 Pacific NW Typhoon Season ACE pdf
- Global Tropical Cyclone Best Track Database
- Hurricane Metrics
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic