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[机构公布] NOAA预测2012年飓风季节的风暴提前

匿名  发表于 2012-5-25 23:56 |阅读模式
Storms Ahead: NOAA’s Outlook for 2012 Hurricane Season
•        Published: May 24th, 2012

By Andrew Freedman

The 2012 hurricane season, which has already gotten off to an early start, is likely to feature “near-normal” storm activity, government officials said on Thursday. The hurricane season outlook from the National Oceanic and Atmospheric Administration (NOAA) calls for a 70 percent chance that there will be between nine to 15 named storms with winds of 39 mph or higher, of which four to eight will strengthen to a hurricane with top winds of 74 mph or higher.

Of those hurricanes, the NOAA is forecasting one to three of them will become a major hurricane, with maximum sustained winds of 111 mph or higher.

Based on the period 1981-2010, an average season produces 12 named storms with six hurricanes, including three major hurricanes. A major hurricane of Category 3 intensity or greater has not struck the U.S. since 2005’s Wilma made landfall in Florida, a record gap for the U.S., which suggests that luck may run out sooner rather than later.
根据1981年至2010年期间,平均季节产生12个命名风暴与6个飓风,其中包括三个主要的飓风。自2005年威尔玛在佛罗里达州登陆以来, 没有CAT3类强度或更大的主要飓风袭击美国,对于美国是创纪录的空隙,这表明,好运可能不再持续多久。

Forecasters cautioned that the outlook of a near-normal season does not mean that it will be a less costly one in terms of lives lost and property destroyed.

“That’s still a lot of activity . . . just because we’re predicting a near normal season doesn’t mean anybody’s off the hook,” said Gerry Bell, NOAA’s lead seasonal hurricane forecaster.
“这仍然有很多活动。 。 。只是因为我们预测接近正常季节,并不意味着任何人都能脱身,“NOAA季节性飓风预报的负责人Gerry Bell说。

NOAA officials reminded reporters of a hurricane season 20 years ago that was below average in terms of overall storm activity, but it took just one storm — Category 5 Hurricane Andrew, which tore across southern Florida — to make it a historically deadly and damaging season.
NOAA的官员提醒记者,飓风季节20多年前在整体风暴活动方面低于平均值,但仅一个风暴 - CAT5的安德鲁飓风,摧毁了整个佛罗里达州南部 –它制造出历史上致命的和破坏性的季节。

Bill Read, the outgoing head of the National Hurricane Center in Miami told reporters that Hurricane Irene serves as a reminder that hurricanes are not just a concern for coastal residents. Much of that storm’s damage took place due to inland flooding in the Mid-Atlantic and Northeast. “This is not the first time that Mother Nature has taught us this lesson.”
在迈阿密的国家飓风中心即将离任的负责人Bill Read告诉记者,飓风艾琳作为提醒,不只是为沿岸居民对飓风提供关注。该风暴的伤害大多发生在大西洋州中部和东北部的内陆洪水。 “这不是第一次了,大自然已经告诉我们这个教训。”

The 2012 hurricane season doesn’t officially start until June 1, but there has already been one tropical storm, Alberto, a compact storm that meandered off the coast of South Carolina in mid-May before dissipating.

The hurricane outlook reflects competing factors. Although the North Atlantic is still in an active hurricane phase that began in 1995 -- 12 of the past 17 seasons have been above normal — there is a possibility that conditions will become less favorable for tropical storms and hurricanes to develop later in the season due to the projected development of El Nino conditions in the Pacific Ocean.
飓风展望反映了矛盾的因素。北大西洋虽然仍是飓风活跃的阶段,在1995年开始 - 过去17个风季中的12个已高于正常 – 还有一种可能性,对热带风暴和飓风将变得不那么有利,由于预计本季在太平洋稍后发展的厄尔尼诺现象。

El Nino events tend to increase winds in the upper atmosphere over the Atlantic, and these winds can tear apart nascent storms.

This year, forecasters will enter the season with two new assets at their disposal, both of them the result of applying military technology for civilian purposes. NASA and NOAA are collaborating on a project to fly two Global Hawk aerial drones into and above Atlantic storms to observe them, and NOAA is also planning to steer small robotic boats into the heart of the powerful storms in order to get observations from areas that are too dangerous for people to venture.
今年,本季预测将增加两个新掌握的技术,他们将运用的军事技术转用于民用目的。 NASA和NOAA的合作项目,两个“全球鹰”高空无人驾驶飞机飞入大西洋风暴上空以观察他们,NOAA还计划带领小机器人的船进入强大的风暴中心,代替人冒险从该区域获得的观测资料。

Frank Marks, the director of NOAA’s Hurricane Research Division, said the drones have instruments that are similar to NOAA’s famous manned “hurricane hunter” aircraft, but it’s not yet clear how beneficial they will be for improving forecast accuracy.
NOAA的飓风研究部主任Frank Marks说,无人驾驶飞机类似于NOAA著名的载人“飓风猎人”飞机的仪器,但目前还在探索将如何有利于提高他们预测的准确性。

NOAA’s seasonal outlook is similar to those issued by private forecasting firms and university researchers, with an emerging consensus that this is not likely to be a blockbuster season in terms of the number of storms. But much depends on where any storms make landfall.

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发表于 2012-5-26 01:04 | 显示全部楼层
Meow, a sex-starved pussy, gets aroused when everyone at the pool stares at her white and soaked up swimsuit turning see-through and exposing her tempting body.

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 楼主| 发表于 2012-5-26 14:52 | 显示全部楼层
NOAA predicts near-normal Eastern Pacific hurricane season
May 24, 2012

NOAA’s Climate Prediction Center today announced that climate conditions point to a near-normal hurricane season in the Eastern Pacific this year. The outlook calls for a 50 percent probability of a near-normal season, a 30 percent probability of a below-normal season and a 20 percent probability of an above-normal season.
NOAA气候预测中心今天宣布,气候条件表明今年在东太平洋的飓风季节接近正常。展望指出接近正常季节有50%的概率,低于正常季节有30%的概率,高于正常季节有 20%的概率。

Seasonal hurricane forecasters estimate a 70 percent chance of 12 to 18 named storms, which includes 5 to 9 hurricanes, of which 2 to 5 are expected to become major hurricanes (Category 3, 4 or 5 on the Saffir-Simpson Hurricane Wind Scale).
季节性飓风预报估计12至18个命名风暴有70%的概率,其中包括5至9个飓风,其中2至5个有望成为主要飓风(萨菲尔 - 辛普森飓风风级3,4或5类)。

An average Eastern Pacific hurricane season produces 15 named storms, with eight becoming hurricanes and four becoming major hurricanes. The Eastern Pacific hurricane season runs from May 15 through Nov. 30, with peak activity from July through September.

This outlook is based on the analysis and prediction of two competing climate signals:

Ongoing conditions, such as increased wind shear, that have been suppressing eastern Pacific hurricane seasons since 1995, and
一、        自1995年以来增加的风切变持续条件,一直抑制东太平洋飓风季节。

The possible development of El Niño later in the season, with warmer waters in the eastern tropical Pacific Ocean, which can decrease the vertical wind shear and increase hurricane activity in the eastern Pacific region.

“The eastern Pacific has gotten off to a busy and early start of the season, with Tropical Storm Aletta last week and Hurricane Bud churning off the Mexican coast this week,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center, part of the U.S. National Weather Service. “NOAA’s seasonal hurricane outlook gives people an idea of how the season will likely unfold so they will be prepared and equipped to respond when disaster strikes. Despite our predictions, it only takes one hurricane to cause a lot of damage and loss of life if people aren’t prepared.”
“本季东部地区已变得热闹和起步较早,上周的热带风暴Aletta和本周的飓风Bud翻腾在墨西哥海岸,”美国国家气象服务的一部分,NOAA气候预测中心的季节性飓风预报负责人Gerry Bell,博士说。 “NOAA的飓风季节展望,本季很可能会展开提供给人们怎样的主意,让他们将有准备和有能力以应对灾难的来袭。尽管有我们的预测,如果没有准备的人,只需要一次飓风就能造成大量的破坏和生命损失。”

The outlook is a general guide to the overall seasonal hurricane activity. It does not predict whether, where, or when any of these storms may hit land. Residents, businesses and government agencies of coastal and near-coastal regions should always prepare prior to each and every hurricane season regardless of the seasonal hurricane outlook.

Eastern Pacific tropical storms most often track westward over open waters, sometimes reaching Hawaii and beyond. However, some occasionally head toward the northeast and may bring rainfall to the arid southwestern United States during the summer months. Also, during any given season, two to three tropical storms can affect western Mexico or Central America.

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 楼主| 发表于 2012-5-27 17:51 | 显示全部楼层
NOAA 2012 Atlantic Hurricane Season Outlook
NOAA 2012年大西洋飓风季节展望
Issued: 24 May 2012
Atlantic Hurricane Outlook ; Seasonal Climate Summary Archive


The 2012 Atlantic hurricane season outlook is an official product of the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC). The outlook is produced in collaboration with scientists from the National Hurricane Center (NHC) and the Hurricane Research Division (HRD). The Atlantic hurricane region includes the North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico.
Interpretation of NOAA’s Atlantic hurricane season outlook

This outlook is a general guide to the expected overall activity during the upcoming hurricane season. It is not a seasonal hurricane landfall forecast, and it does not predict levels of activity for any particular region.

Hurricane disasters can occur whether the season is active or relatively quiet. It only takes one hurricane (or tropical storm) to cause a disaster. Residents, businesses, and government agencies of coastal and near-coastal regions are urged to prepare for every hurricane season regardless of this, or any other, seasonal outlook. NOAA, the Federal Emergency Management Agency (FEMA), the National Hurricane Center (NHC), the Small Business Administration, and the American Red Cross all provide important hurricane preparedness information on their web sites.

NOAA does not make seasonal hurricane landfall predictions

NOAA does not make seasonal hurricane landfall predictions. Hurricane landfalls are largely determined by the weather patterns in place as the hurricane approaches, which are only predictable when the storm is within several days of making landfall.
Nature of this Outlook and the \"likely\" ranges of activity
本展望的性质和活动的“可能” 范围

This outlook is probabilistic, meaning the stated “likely” ranges of activity have a certain likelihood of occurring. The seasonal activity is expected to fall within these ranges in 7 out of 10 seasons with similar climate conditions and uncertainties to those expected this year. They do not represent the total possible ranges of activity seen in past similar years.


This outlook is based on 1) predictions of large-scale climate factors known to influence seasonal hurricane activity, and 2) climate models that directly predict seasonal hurricane activity.
Sources of uncertainty in this seasonal outlook

1. Predicting El Niño and La Niña (also called the El Niño-Southern Oscillation- ENSO) impacts is an ongoing scientific challenge facing climate scientists today. Such forecasts made during the spring generally have limited skill.
1。预测厄尔尼诺和拉尼娜现象(也称为厄尔尼诺 - 南方涛动,ENSO)的影响,是气候科学家今天所面临的一个正在进行的科学挑战。春季期间作出这样的预测,技能一般都是有限的。

2. Many combinations of named storms and hurricanes can occur for the same general set of climate conditions. For example, one cannot know with certainty whether a given climate signal will be associated with several short-lived storms or fewer longer-lived storms with greater intensity.

3. Model predictions of sea-surface temperatures, vertical wind shear, moisture, and stability have limited skill this far in advance of the peak months (August-October) of the hurricane season.

4. Weather patterns that are unpredictable on seasonal time scales can sometimes develop and last for weeks or months, possibly affecting seasonal hurricane activity.
2012 Atlantic Hurricane Season Outlook: Summary

NOAA’s 2012 Atlantic Hurricane Season Outlook indicates that a near-normal season is most likely. The outlook calls for a 50% chance of a near-normal season, a 25% chance of an above normal season, and a 25% chance of a below-normal season. See NOAA definitions of above-, near-, and below-normal seasons. The Atlantic hurricane region includes the North Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico.
NOAA的2012年大西洋飓风季节展望指出,本风季接近正常是最有可能的。展望指出了接近正常季节的可能性为50%,25%的几率高于正常季节, 25%的几率低于正常季节。以上,接近,低于正常季节参见NOAA definitions。大西洋飓风的区域包括北大西洋,加勒比海和墨西哥湾。
This outlook reflects the possibility of competing climate factors, combined with several circulation and sea surface temperature (SST) features that suggest a less active season compared to many in recent years. Favoring an above-normal season is the ongoing conditions that have been associated withincreased Atlantic hurricane activity since 1995, combined with expected near-average SSTs across much of the tropical Atlantic Ocean and Caribbean Sea (called the Main Development Region, or MDR).
1figure2.gif 2figure3.gif 3figure4.gif
A potentially competing climate factor is the possible development of El Niño during the season. If El Niño develops, it could make conditions less conducive for hurricane formation and intensification during the peak months (August-October) of the season, thus shifting the activity toward the lower end of the predicted range.


If they persist, two other factors that are now present could also compete with conditions associated with the high-activity era. These are: 1) Enhanced vertical wind shear across the MDR, and 2) Cooler-than-average SSTs in the far eastern tropical Atlantic.
Given the current and expected conditions, combined with model forecasts and possible competing factors, we estimate a 70% probability for each of the following ranges of activity during 2012:
•        9-15 Named Storms,
•        9-15个命名风暴
•        4-8 Hurricanes
•        4-8个飓风
•        1-3 Major Hurricanes
•        1-3个主要飓风
•        An Accumulated Cyclone Energy (ACE) range of 65%-140% of the median.
•        累计气旋能量(ACE)的范围65%-140%中位数。
The seasonal activity is expected to fall within these ranges in 70% of seasons with similar climate conditions and uncertainties to those expected this year. These ranges do not represent the total possible ranges of activity seen in past similar years.
Note that the above ranges are centered near the official NHC 1981-2010 seasonal averages of 12 named storms, 6 hurricanes, and 3 major hurricanes
需要注意的是上述范围中心接近NHC 1981年至2010年季节的12个命名风暴,6个飓风和3个主要飓风的平均。
This Atlantic hurricane season outlook will be updated in early August, which coincides with the onset of the peak months of the hurricane season.
Hurricane Landfalls:

It only takes one storm hitting your area to cause a disaster, regardless of the overall activity predicted in the seasonal outlook. Therefore, residents, businesses, and government agencies of coastal and near-coastal regions are urged to prepare every hurricane season regardless of this, or any other, seasonal outlook.
Predicting where and when hurricanes will strike is related to daily weather patterns, which are not reliably predictable weeks or months in advance. Therefore, it is currently not possible to reliably predict the number or intensity of landfalling hurricanes at these extended ranges, or whether a given locality will be impacted by a hurricane this season.

1.        Expected 2012 activity
1。     预计2012年活动
Climate signals and evolving oceanic and atmospheric conditions, combined with dynamical model forecasts, indicate that a near-normal 2012 Atlantic hurricane season is most likely. This outlook calls for a 50% chance of a near-normal season, a 25% chance of an above-normal season, and a 25% chance of a below normal season.
An important measure of the total overall seasonal activity is NOAA’sAccumulated Cyclone Energy (ACE) index, which accounts for the intensity and duration of named storms and hurricanes during the season. This outlook indicates a 70% chance that the 2012 seasonal ACE range will be 65%-140% of the median. According to NOAA’s hurricane season classifications, an ACE value above 111% of the 1981-2010 median reflects an above-normal season. An ACE value below 71.4% of the median reflects a below-normal season.
总的整体季节性活动的一项重要举措,是NOAA\'累计气旋能量(ACE)指数,它对应的是命名风暴及飓风在季节期间的强度和持续时间。本展望表示,2012年季节性ACE的范围有70%的几率将达到中位数的65%-140%。根据NOAA的飓风季节分类,1981年至2010年ACE值超过中位数的111%,反映了高于正常的季节。 ACE值低于中位数的71.4%,反映了低于正常的季节。
Consistent with the expected ACE range, the 2012 Atlantic hurricane season is predicted to produce (with 70% probability for each range) 9-15 named storms, of which 4-8 are expected to become hurricanes, and 1-3 are expected to become major hurricanes. These ranges are centered near the 1981-2010 period averages of 12 named storms, 6 hurricanes and 3 major hurricanes.
与预期的ACE范围相一致,2012年大西洋飓风季节预计产生(每个范围内的概率70%)9-15个命名风暴,其中4-8个有望成为飓风, 1-3个有望成为主要飓风。这些范围在1981年至2010年期间平均12个命名风暴、6个飓风和3个主要飓风的中心值附近。

2.        Science behind the 2012 Outlook
2.        2012年展望版背后
The 2012 seasonal hurricane outlook reflects the possibility of competing climate factors, combined with current conditions in the MDR (which includes the Caribbean Sea and tropical Atlantic ocean between 9oN-21.5oN; Goldenberg et al. 2001) which are less-conducive compared to those seen in many past active seasons.
2012年飓风季节展望反映了竞争气候因素的可能性,结合MDR(其中包括加勒比海和热带大西洋9oN-21.5oN之间; Goldenberg等2001)目前的条件,竞争气候因素可能比那些在过去许多活跃季节所看到的不太有利。
The three main climate factors for this outlook are the tropical multi-decadal signal (which reflects conditions associated with the ongoing high-activity era), the El Niño/ La Niña cycle (ENSO), and tropical Atlantic SSTs. Favoring an above-normal season is the expected continuation of conditions associated with the Atlantic high-activity era that began in 1995, combined with the expectation of continued near-average SSTs in the Main Development Region.
The main competing climate factor is the possible development of El Niño later in the summer or early fall. If El Niño develops, it could make conditions less conducive to hurricane formation and intensification during August-October (the peak months of the season), perhaps shifting the seasonal activity toward the lower end of the predicted range.
The outlook also takes into account dynamical model predictions from the NOAA Climate Forecast System (CFS), NOAA’s Geophysical Fluid Dynamics Lab (GFDL) model CM2.1, the European Centre for Medium Range Weather Forecasting (ECMWF), the United Kingdom Meteorology (UKMET) office, and the EUROpean Seasonal to Inter-annual Prediction (EUROSIP) ensemble.
These models show large spreads in the ENSO forecasts for ASO, ranging from ENSO-Neutral to a moderate-strength El Niño episode. As a result, their forecasts for the Atlantic hurricane season also show a considerable spread, ranging from slightly above normal to slightly below normal.
这些模型显示, ASO在ENSO预测中大的偏差,从ENSO的中性到中等强度的厄尔尼诺情节不等。大西洋飓风季节的预测结果,也显示了相当大的差别,范围从略高于正常到略低于正常。

Two other factors, which are now present, also suggest that the MDR could be less conducive to an active hurricane season. These are: 1) Enhanced wind shear resulting from strong upper-level westerly winds across the MDR, and 2)Below-average SSTs in the far eastern tropical Atlantic in association with the recent La Niña episode. Because of uncertainties in the upcoming ENSO evolution (i.e., ENSO-Neutral or El Niño), it is unclear whether these factors will persist throughout the hurricane season.
另外两个因素,这是现在存在的,也表明MDR可能不太有利于活跃的飓风季节。它们是:1)整个MDR强大的上层西风造成风切变增强, 2)极东热带大西洋低于平均的SSTs同近来的拉尼娜事件有关联。在即将到来的ENSO演变(即ENSO中性或厄尔尼诺)不确定性原因,目前还不清楚这些因素是否将持续整个飓风季节。

The CFS model is predicting the vertical wind shear within the MDR to become below-average in the next few months as the upper-level westerlies weaken. The CFS is also predicting the SSTs in the far eastern tropical Atlantic to return to near-average, which reflects the demise of La Niña and no development of El Niño (i.e. ENSO-Neutral). Other models predict El Niño to develop, and consequently they call for the vertical wind shear to remain strong.

a.        Expected continuation of tropical multi-decadal signal
a.        预计热带多年代际信号持续

One factor guiding this outlook is the expected continuation of the tropical multi-decadal signal (Bell and Chelliah 2006), which has contributed to the current high-activity era in the Atlantic basin that began in 1995. This signal incorporates the warm phase of the Atlantic Multi-decadal Oscillation (AMO) and an enhanced west African monsoon system. It is associated with inter-related atmospheric conditions that are conducive to increased Atlantic hurricane activity.
During 1995-2011, some key aspects of the tropical multi-decadal signal within the MDR have included reduced vertical wind shear and weaker easterly trade winds, below-average sea-level pressure, a configuration of the African easterly jet that is more conducive to hurricane development from tropical cloud systems (aka Easterly waves) moving off the African coast, and warmer than average SSTs.
Two key aspects of the tropical multi-decadal signal are now present: the warm phase of the AMO, along with weaker mid-level easterly winds across the eastern tropical Pacific and tropical Atlantic Ocean. During ASO, this wind pattern typically produces a more conducive configuration of the African Easterly Jet.

However, other features of the tropical multi-decadal signal are not yet present, as indicated by strong northeasterly trade winds extending southward into the northeastern MDR, and by enhanced upper-level westerly winds and strong vertical wind shear across the MDR.
Note that it is not possible to know with certainty whether the tropical multi-decadal signal is indeed continuing during 2012, and current climate models cannot skillfully forecast the multi-decadal variability of the Atlantic climate system. However, given that the warm AMO phase now present has also been present for the past 17 years, and that this SST pattern has been previously linked to the tropical multi-decadal signal, it is reasonable to expect that this signal is again present in 2012. If so, this would reflect a continuation during the 2012 Atlantic hurricane season of the active Atlantic phase of the tropical multi-decadal signal that began in 1995.
b.        Expected near-average SSTs in the Main Development Region
b.        预计主要发展地区的SSTs接近平均
The second factor guiding this outlook is the expectation of near-average SSTs across most of the MDR during ASO, and the possibility of continued below-average SSTs in the far eastern tropical Atlantic. These expectations are based on current observations, the high-activity era, the dissipation of La Niña, and model forecasts for the possibility of El Niño.
Sea surface temperatures measured over the entire MDR are currently near-average, with below-average SSTs in the far eastern tropical Atlantic and above-average SSTs in the central and western MDR. These departures are considerably less than was observed last year at this time, and are consistent with a springtime cooling and enhanced northeasterly trade winds typical of La Niña. Given that La Niña has dissipated.
A concern for this outlook is that seasonal Atlantic hurricane activity can be especially sensitive to SST departures in the eastern tropical Atlantic. Below average SSTs in that region during ASO are typically associated with stronger northeasterly trade winds and less conducive thermodynamics, both of which can suppress hurricane activity. Another current feature of interest is that the average SST departures in the MDR are comparable to those of the remainder of the global tropics. If this condition persists, it is also suggestive of a less active season.
这个展望关注的是季节性大西洋飓风活动,可以是特别敏感的热带大西洋东部的SST偏差。在区域ASO期间SSTs低于平均,通常在该地区伴有较强的东北风信风和不利于热动力,这两者可以抑制飓风活动。目前感兴趣的另一个特点是, MDR平均SST偏差在全球热带地区的其余部分。如果这种情况持续存在,这也意味着一个不太活跃的季节。
There is considerable uncertainty in forecasting ASO SSTs for the tropical Atlantic so far in advance, partly because of forecast uncertainties in the strength of the west African monsoon system and partly because of uncertainties in predicting ENSO. The CFS high-resolution model is predicting the SSTs in the far eastern tropical Atlantic to return to near-average, which reflects the demise of La Niña and no development of El Niño (i.e. ENSO-Neutral). Conversely, the CFS low-resolution model is predicting SSTs in the eastern tropical Atlantic to remain below average.
迄今,还在预测热带大西洋ASO SSTs上存在相当大的不确定性,部分原因是西非季风系统强度预报的不确定性,部分原因是因为ENSO预测的不确定性。CFS的高分辨率模型预测在远东热带大西洋SSTs返回到接近平均水平,反映出拉尼娜现象的消亡和没有厄尔尼诺(即ENSO中性)的发展。相反,CFS低分辨率模型预测热带大西洋东部的SSTs仍低于平均水平。
c.        ENSO-Neutral or El Niño conditions likely
c.        ENSO中性或厄尔尼诺条件的可能性
Another climate factor known to significantly impact Atlantic hurricane activity is ENSO. The three phases of ENSO are El Niño, La Niña, and ENSO-Neutral. El Niño events tend to suppress Atlantic hurricane activity, while La Niña events tend to enhance it (Gray 1984). These typical impacts can be strongly modulated by conditions associated with a low- or high-activity era.
另一个明显影响大西洋飓风活动的气候因素称为ENSO。 ENSO的三个阶段是厄尔尼诺现象,拉尼娜现象与ENSO的中性。厄尔尼诺事件倾向于抑制大西洋飓风的活跃,而拉尼娜事件往往以提高它(Gray 1984)。这些典型的影响,可以是强的低或高活性年代条件调控。
The 2011-12 La Niña episode dissipated in April, as equatorial SSTs across the central and east-central Pacific returned to near-average and SSTs in the eastern Pacific became above average. Based on observations and ENSO forecast models, the official CPC/IRI ENSO forecast issued in early Mayindicates that ENSO-Neutral conditions are likely through the summer with approximately equal chances of Neutral and El Niño conditions during the fall.
2011-12拉尼娜现象在四月消散,横跨中部和中东部太平洋赤道的SSTs返回到接近平均水平,以及在东太平洋SSTs变得高于平均水平。根据观测和ENSO的预测模型, CPC/ IRI官方在五月初公布的ENSO预测,表明ENSO的中性条件可能通过夏季,在秋季有中性和厄尔尼诺条件大致相等的几率。
Predicting the various phases of ENSO and their impacts is an ongoing scientific challenge facing climate scientists today. Such forecasts made during the spring generally have limited skill. The present uncertainty in the model forecasts is indicated by the large spread in predicted SST departures in the east-central equatorial Pacific during ASO 2012. Approximately one-half of the models predict ENSO-Neutral conditions (defined by the CPC as SST departures in the Niño 3.4 region between -0.5oC and +0.5oC) during the hurricane season. Also, approximately one-half of the models predict El Niño conditions (Niño 3.4 SST departures above +0.5oC).
预测ENSO事件及其影响的各个阶段,是一项正在进行的科学,也是气候科学家今天所面临的挑战。春季期间作出这样的预测一般都技能有限。由2012年ASO期间在东部、赤道太平洋中部SST偏差扩展的预测,表明目前该模型预测的不确定性。在飓风季节,约一半的模型预测ENSO为中性条件(CPC定义Niño 3.4区域SST偏差在-0.5C° 和 +0.5C °之间)。此外,约一半的模型预测厄尔尼诺现象(Niño 3.4 SST 偏差高于+0.5C°)。
This spread in the model forecasts, combined with the limited predictive skill exhibited by all such models at this time of the year, is a main reason why we are presently indicating only a 25% chance of an above-normal season. If El Niño fails to develop, the probability of an above- normal Atlantic hurricane season will be higher and the actual seasonal activity will likely be toward the upper end of our predicted ranges. ENSO and other climate conditions will be re-evaluated for the update of this outlook to be issued in early August.
该模型预测的扩散结合有限的预测技能,所有这些模型在这一年时间里的表现,是我们目前表明高于正常季节只有25%几率的一个主要原因。厄尔尼诺如果不发展,大西洋飓风季节高于正常的概率将会更高,实际的季节性活动很可能会转向我们预测范围的上端。 将对该展望的ENSO和其他气候条件重新评估进行更新,须在八月初公布。

3.        Multi-decadal fluctuations in Atlantic hurricane activity
3。     大西洋飓风活动的多年代际波动
Atlantic hurricane seasons exhibit extended periods lasting decades of generally above-normal or below-normal activity. These fluctuations in hurricane activity result almost entirely from differences in the number of hurricanes and major hurricanes forming from tropical storms that first develop in the MDR.
The current high-activity era has been in place since 1995. Hurricane seasons during 1995-2011 have averaged about 15 named storms, 8 hurricanes, and 4 major hurricanes, with an ACE index of 153% of the median. NOAA classifies 12 of the 17 seasons since 1995 as above normal, with eight being extremely active (i.e., hyperactive defined by ACE > 165% of median). Only five seasons since 1995 have not been above normal, which include the 2007 season and four El Niño years (1997, 2002, 2006, and 2009).
This high level of activity since 1995 contrasts sharply to the low-activity era of 1971-1994 (Goldenberg et al. 2001), which averaged only 8.5 named storms, 5 hurricanes, and 1.5 major hurricanes, and had an average ACE index of only 74% of the median. One-half of the seasons during this low-activity era were below normal, only three were above normal (1980, 1988, 1989), and none were hyperactive.
自1995年以来这种高水平的活动,与1971年至1994年低活性的年代形成急剧反差(Goldenberg等人,2001年),平均只有8.5个命名风暴,5个飓风和1.5个主要飓风, ACE指数中位数平均只有74%。在这个低活性年代的风季一半低于正常,只有三个高于正常(1980年,1988年,1989年),并没有异常活跃。
Within the MDR, the atmospheric circulation anomalies that contribute to these long-period fluctuations in hurricane activity are strongly linked to the Tropics-wide multi-decadal signal (Bell and Chelliah 2006), which incorporates the warm phase of the AMO and an enhanced west African monsoon system.. A change in the phase of the tropical multi-decadal signal coincides with the transition in 1995 from a low-activity era to the current high-activity era.
MDR范围内,大气环流异常有助于这些在飓风活动中的长周期波动,是与热带范围内的多年代际信号密切相关的(Bell和Chelliah 2006),其中包括AMO的暖位相和增强的西部非洲季风系统......从1995年的低活性年代过渡到目前的高活性年代,与热带多年代际信号相位的变化相吻合。

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