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[机构公布] 2012年北极报告单(节选)

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匿名  发表于 2012-12-8 17:51 |阅读模式
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The Arctic Report Card 2012 highlights the dramatic impact of persistent warming in the Arctic, which witnessed numerous record-setting melting events this year.
2012年北极报告单凸显了北极地区持续变暖的巨大影响。在那儿,今年已见证了无数创纪录的熔融事件。

“Multiple observations provide strong evidence of widespread, sustained changes driving the Arctic environmental system into a new state,” according to the Report Card compiled by the U.S. National Oceanic and Atmospheric Administration and international partners (AMAP, CAFF, ARCUS).
“多重观察提供的有力证据表明,广泛、持续的变化驱动着北极环境系统进入一个新状态,”根据美国国家海洋和大气管理局与国际合作伙伴(AMAP, CAFF, ARCUS)编制的报告单。

Changes in the sea ice cover, snow cover, glaciers and Greenland ice sheet are reducing the overall surface reflectivity, with bright, white surfaces that reflect summer sunlight being replaced by darker surfaces, e.g., ocean and land, which absorb sunlight. These conditions increase the capacity to store heat within the Arctic system, which enables more melting - a positive feedback.
海冰盖、积雪、冰川和格陵兰岛冰盖的变化降低了总体的表面反射率,反射夏季阳光的亮白色表面被吸收阳光的海洋和陆地等暗色表面所替代。这些条件加大了北极系统储热的容量,积极地促进了那儿更多的冰雪融化 。

“Thus, we arrive at the conclusion that it is very likely that major changes will continue to occur in the Arctic in years to come, particularly in the face of projections that indicate continued global warming,” it said.
“因此我们得出结论:在未来几年内,北极地区很可能将会继续发生重大变化,尤其是面对预测所指出的全球持续变暖,”报告单说。

A second key point in Report Card 2012 is that changes in the Arctic marine environment are affecting the foundation of the food web in both the terrestrial and marine ecosystems.
2012年报告单的第二个要点是,北极海洋环境的变化正影响着陆地和海洋生态系统食物链的基础。

Highlights of the Report Card include:
报告单的要点包括:
• Record low snow extent and low sea ice extent in June and September respectively
•六月的积雪程度和九月的海冰面积分别创历史新低

• Increasing growing season length, tundra greenness and above-ground biomass. Below the tundra, record high permafrost temperatures in northernmost Alaska
•绿色苔原和地面以上生物量的生长期延长。阿拉斯加北部苔原下面的多年冻土温度创新高

• Longest observed duration of melting on the Greenland ice sheet, with a rare, nearly ice sheet-wide melt event in July.
•观测到持续时间最长的格陵兰岛冰盖融化,以及几乎罕见的7月冰盖融化事件。
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 楼主| 发表于 2012-12-8 21:44 | 显示全部楼层
第一部分
Atmosphere Summary
大气摘要
atmos_pres_greenland_resize.png
Extended high pressure over southern Greenland (left) caused anomalously high air temperatures (right) and extensive melting at the surface of the ice sheet (see essay on Greenland Ice Sheet). Large version available from NOAA Climate.gov.
格陵兰岛南部扩展的高压(左)造成异常高的气温(右)冰盖表面的大范围熔融,(请参阅文章格陵兰冰盖). Large version NOAA Climate.gov提供。
October 2011 through August 2012 was a departure from typical atmospheric conditions of recent years (2003-2010) in that warm temperature anomalies were relatively small over the central Arctic relative to the late 20th Century. Similarly, cloud cover in 2012 was average compared to the period 2001-2010. Stratospheric ozone concentrations during spring 2012 were also within normal ranges and considerably lower than those in spring 2011, when unprecedented chemical ozone losses occurred. Air sampling sites in the Arctic continue to measure rising greenhouse gas concentrations from worldwide human sources, and indicate that there is, as yet, no direct atmospheric evidence that Arctic emissions of CH[sub]4[/sub] or the net balance of C from CO[sub]2[/sub] are changing.
201110月至20128月,偏离了近几年(2003-2010年)的典型大气条件,与20世纪后期相比,北极中部的那个温度暖距平相对较小。2012年云量与2001年至2010年期间的平均相比也同样如此。当化学臭氧发生空前损耗时,2012年春季期间的平流层臭氧浓度在正常范围内,并大大低于2011年春季。北极地区的空气采样点持续测量到源于人类本身的温室气体浓度正在上升,并指出,到目前为止,大气没有直接的证据表明北极的CH4排放或来自CO2C净平衡正在发生变化。
Notable weather activity in fall 2011 and winter 2012 occurred in the sub-Arctic due to a strong positive North Atlantic Oscillation (NAO) Index, which promoted westerly winds in the northern North Atlantic Ocean region and warm temperatures in western Eurasia and the Kara Sea. Further east, in the Siberian sub-Arctic, unusually cold winter conditions caused many fatalities. Though 2012 saw a new record summer minimum sea ice extent for the satellite period starting in 1979, the atmospheric forcing conditions were very different than those during the previous record retreat of 2007. In 2012, southerly winds in early June and a major storm in August in the East Siberian and Chukchi seas enhanced sea ice retreat, whereas a persistent warm and windy pattern was responsible for more rapid sea ice melt than normal in 2007. Also noteworthy in 2012 was NAO-related high sea level pressure over Greenland in early summer, a feature of the last six years that has promoted greater than expected mass loss from Greenland and Canadian Arctic glaciers and reduced snow cover in North America.
2011年秋季和2012年冬季在亚北极出现的显着的天气活动,是由于北大西洋涛动(NAO)较强的正指数,助长了北大西洋北部地区的西风以及欧亚大陆西部和喀拉海温暖的温度。再往东,在亚北极地区的西伯利亚,酷寒的冬季条件造成了许多人死亡。尽管2012年创下了自1979年有卫星记录以来夏季海冰最小程度的新记录,但大气条件根本不同于旧记录2007年中的那些条件。在东西伯利亚和楚科奇海,20126月初的偏南风和8月大风暴加剧了海冰的退缩,而2007年,持续温暖和多风的模式使海冰比正常更快速的融化。 2012年还值得一提的是与NAO相关的因素——初夏格陵兰上的高气压,它是过去6年的一个特点,已促进了格陵兰岛和加拿大北极冰川比预期更大的质量损耗以及北美积雪的减少。
帖子中涉及地图来源广泛,图中所涉及的行政区域以中国官方认定的为准。
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 楼主| 发表于 2012-12-9 00:20 | 显示全部楼层
(一)

Air Temperature, Atmospheric Circulation and Clouds
气温、大气环流和云量

Highlights
。要点
October 2011 through August 2012 was a departure from typical atmospheric conditions of recent years (2003-2010), in that temperature anomalies were small over the central Arctic. Most of the notable weather activity in fall and winter occurred in the sub-Arctic due to a strong positive North Atlantic Oscillation. Summer 2012 was dominated by low sea level pressure.
•201110月至20128月偏离了近几年(2003-2010年)典型的大气条件,北极中部的温度距平相对较小。由于北大西洋涛动处于很强的正位相,亚北极显着的天气活动大多发生在秋季和冬季。 2012年夏季由低海平面气压占主导。
Three severe weather events included (1) unusual cold in late January to early February 2012 across Eurasia, and (2) two record storms characterized by deep central pressure and strong winds near western Alaska in November 2011 and north of Alaska in August 2012.
•三个灾害性天气事件包括:(120121月下旬到2月初横跨欧亚大陆的严寒,(2201111月接近阿拉斯加西部的风暴,(320128月阿拉斯加北部的风暴。这两个风暴的特点是中心气压低和风力强。

Mean Annual Surface Air Temperature
年均表面气温

In contrast to the years 2003 through 2010, which had substantial positive temperature anomalies in the central Arctic, the period October 2011-August 2012 showed positive temperature anomalies in the sub-Arctic rather than over the central Arctic Ocean (Fig. 1.1).
通过2003年到2010年多年的对比,其中北极中部有相当程度的正温度距平。 201110 - 20128月期间显示的正温度距平出现在亚北极地区,而不是北冰洋中部(图1.1)。



Fig. 1.1. Annual average (October 2011 through August 2012) near-surface air temperature anomalies relative to the period 1981-2010. Data are from NOAA/ESRL, Boulder, CO: http://www.esrl.noaa.gov/psd/.
1.1. 201110月至20128月与1981-2010间近表面气温年度平均距平的比较。数据来自NOAA / ESRLBoulder, COhttp://www.esrl.noaa.gov/psd/

Over a longer time interval, the annual mean surface air temperature over Arctic land areas has experienced an overall warming of about +2ºC since the mid-1960s (Fig. 1.2). In 2011, the annual mean air temperature was slightly warmer than in 2009 and 2010. The cooler temperatures in 2009 and 2010 reflected cold continents in winter, while Eurasia had warmer temperatures in spring 2011. The annual mean surface temperature for 2012 is not available, as the year was incomplete at the time of writing.
在较长的时间里,自20世纪60年代中期以来,北极陆地区域的年平均表面气温总体变暖了约2ºC(图1.2)。 2011年的年平均气温比2009年和2010年略有回暖。2009年和2010年更低的温度反映在冬季寒冷的大陆上,而2011年春季,欧亚大陆温度有所回暖。 因无法提供2012年的年平均表面温度,所以今年编写的报告是不完整的。

Positive temperature anomalies were seen everywhere across the central Arctic for the first decade in 21st century (2001-2011) relative to a 1971-2000 baseline period at the end of the 20th Century (Fig. 1.3). This temperature pattern is a manifestation of \\\"Arctic Amplification\\\", which is characterized by temperature increases 1.5°C greater than (more than double) the increases at lower latitudes (Overland et al., 2011; Stroeve et al., 2012).
2001-2011年与1971-2000年基期的比较,横跨北极中部的正温度距平随处可见(图1.3)。这个温度模式是北极放大的一种表现,它的特点是北极地区的升温大于低纬度地区升温1.5°C(两倍以上)(Overland等,2011; Stroeve等人,2012)。

Fig. 1.2. Arctic-wide annual average surface air temperature (SAT) anomalies for the period 1900-2011 relative to the 1981-2010 mean value, based on land stations north of 60°N. Data are from the CRUTEM3v dataset at www.cru.uea.ac.uk/cru/data/temperature/. Note: this curve includes neither marine observations nor 2012 data, as the year was incomplete at the time of writing.

1.2。北极的年平均表面气温(SAT)距平,它基于60°N以北陆地台站于1900年至2011年间的数据,与19812010年的平均值的比较。数据来自CRUTEM3vwww.cru.uea.ac.uk/cru/data/temperature/的数据集。注:这条曲线既不包括海洋观测,也没有2012年的数据,所以今年编写时是不完整的。

Fig. 1.3. Annual average near-surface air temperature anomalies for the first decade of the 21st century (2001-11) relative to the baseline period of 1971-2000. Data are from NOAA/ESRL, Boulder, CO: http://www.esrl.noaa.gov/psd/.

1.3年平均近表面气温距平为2001-2011年与1971-2000年的基期的比较。数据来自NOAA/ESRL, Boulder, COhttp://www.esrl.noaa.gov/psd/


Seasonal Air Temperatures
季节气温
Consistent with the annual average temperatures (Fig. 1.1), each seasonal anomaly distribution for near-surface temperatures shows departures primarily in the sub-Arctic (Fig. 1.4). Fall 2011 and winter 2012 were characterized by a positive North Atlantic Oscillation (NAO). This promotes the warm temperature anomaly over the Barents and Kara Seas, which are downstream of the stronger winds and lower pressures of the Icelandic low pressure center. This is unlike the Warm Arctic/Cold Continents pattern associated with a negative Arctic Oscillation (AO) climate pattern over the central Arctic (see previous Report Cards), which dominated the previous two falls and winters (2009-10 and 2010-11).
季节气温与年平均温度相一致(图1.1),每个季节的近表面温度距平分布显示,偏离主要集中于亚北极(图1.4)。 2011年秋季和2012年冬季的特点是北大西洋涛动(NAO)正位相。这与暖北极/冷大陆模式联合北极中部北极涛动(AO)负位相的气候模式不同(见以前的报告单),它促进了巴伦支海和喀拉海的温度暖距平,那是冰岛低压中心强风和低压的下游。从而主导着前两个秋、冬季(2009-102010-11)。
In contrast to the positive NAO in fall 2011 and winter 2012, spring and summer 2012 had a very negative NAO, with significant consequences for snow cover duration and extent (see the Snow essay) and melting on the Greenland Ice Sheet (see the Greenland Ice Sheet essay). Spring 2012 also saw the early formation of the Arctic Dipole (AD) pattern (Fig. 1.5) with high pressure on the North American side of the Arctic and low pressure on the Siberian side. In the previous five years this has not occurred until June (Overland et al., 2012). The dipole pattern supported increased winds across the Arctic and warmer temperature anomalies over the East Siberian Sea and western Greenland (Fig. 1.4c). In summer 2012 an unusual low pressure, centered on the Pacific Arctic sector, was a new feature of central Arctic weather relative to the last decade (Fig. 1.6).

2011年秋和2012年冬季NAO的正位相相反,2012年春季和夏季的NAO为强负位相,对积雪持续时间和程度(参见雪的文章)以及格陵兰冰盖的融化(参见格陵兰冰盖的文章)都具有显着的影响, 2012年春季北极偶极子(AD)模式(图1.5)形成初期,还发现了北极北美一侧的高压和西伯利亚一侧的低压。在过去五年中, 6月份前都没有发生这情况(Overland等,2012)。偶极子模式支持整个北极的风以及东西伯利亚海和格陵兰西部温度暖距平的增长(图1.4C)。相对于过去十年,2012年夏天的一个异常是北极太平洋区域的低气压中心,它是北极中部气候的一个新特征(图1.6)。
Also noteworthy in Fig. 1.6 is the high sea level pressure over Greenland, which has been a feature of early summer for the last six years. Higher pressures over Greenland and their influence on Arctic and subarctic wind patterns, a so called blocking pattern, suggests physical connections between it and reduced Arctic sea ice in the summer, loss of Greenland and Canadian Arctic glacier ice, reduced North American snow cover in May and June, and potentially extremes in mid-latitude weather (Overland et al., 2012). See the essays on Sea Ice, Glaciers and Ice Caps, Greenland Ice Sheet and Snow for further information on those topics.
1.6里还值得一提的是位于格陵兰岛上的高海平面气压,在过去六年,这一直是初夏的一个特点。格陵兰岛上的高气压和他们的势力影响着北极和亚北极风的模式,即所谓的阻塞模式,意思是它和夏季北极海冰减少之间的物理连接,它使格陵兰岛和加拿大北极地区冰川丢失, 5月和6月的北美积雪减少,以及中纬度地区潜在的极端天气(Overland等,2012)。有关这些主题的更多信息,请参阅海冰、冰川和冰冠、格陵兰冰盖以及雪等文章。
ab
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Fig. 1.4. Seasonal anomaly patterns for near surface air temperatures in 2012 relative to the baseline period 1981-2010. Fall 2011, (a), winter 2012 (b). spring 2012 (c) and summer 2012 (d). Data are from NOAA/ESRL, Boulder, CO: http://www.esrl.noaa.gov/psd/.

1.42012年近表面气温季节距平模式与19812010年基期的比较。2011秋季(a),2012冬季(b)。2012春季(c)和2012夏季(d)。数据来自NOAA/ESRL, Boulder, COhttp://www.esrl.noaa.gov/psd/.


Fig. 1.5. Sea level pressure field for April through June 2012 showing the Arctic Dipole (AD) pattern with high pressure on the North American side of the Arctic and low pressure on the Siberian side. Data are from NOAA/ESRL, Boulder, CO: http://www.esrl.noaa.gov/psd/.
1.5201246月海平面气压场显示了​​北极北美一侧高压和西伯利亚一侧低压的北极偶极子(AD)模式。数据来自NOAA/ESRL, Boulder,CO:http://www.esrl.noaa.gov/psd/

Fig. 1.6. In summer 2012 an extensive low sea level pressure anomaly was centered on the Pacific Arctic sector while high pressure remained over Greenland. Data are from NOAA/ESRL, Boulder, CO: http://www.esrl.noaa.gov/psd/.

1.62012年夏季,一个广泛的低海平面气压距平集中在北极太平洋区域,而高压维持于格陵兰岛。数据来自NOAA/ESRL, Boulder, CO: http://www.esrl.noaa.gov/psd/.

Severe Weather

灾害性天气
The period late 2011 through summer 2012 was notable for three severe weather events.
2011年年底至2012年夏季期间,发生了三个著名的严重天气事件。
The Bering Sea storm of November 2011, one of the most powerful extra-tropical cyclones on record to affect Alaska, caused extensive coastal flooding. Moving northeastward from its origins in the western Pacific Ocean, the storm deepened by 25 hPa in the 24 hours ending November 8, when its central pressure of 945 hPa was comparable to that of a Category 3 hurricane. The storm\'s forward speed exceeded 100 km/hour as it approached Alaska and turned northward, passing just offshore of Alaska\'s western coast, then through the Bering Strait and into the Chukchi Sea. Wind gusts of 144 km/hour and 151 km/hour were recorded on the western Seward Peninsula and Little Diomede Island, respectively.
201111月的白令海风暴,是阿拉斯加记录上影响最大的温带气旋之一,给沿海造成了大范围的洪灾。它起源于西太平洋,向东北方向移动,到118止的24小时内,风暴中心气压降低了25百帕,其945百帕的中心气压相当于CAT3飓风。风暴的前进速度超过100公里/小时,当它接近阿拉斯加时向北转向,擦过阿拉斯加西部海岸的近海,然后通过白令海峡并进入楚科奇海。Seward半岛西部和小Diomede岛分别录得144公里/小时和151公里/小时阵风。
In late January-early February 2012, a warm center occurred over the Kara and Laptev Seas and broader, severe cold anomalies occurred over the northern Eurasian sub-Arctic during a brief period of negative AO (Fig. 1.4b). North America and Eurasia exhibited a sharp contrast in surface temperature anomalies. The United States experienced its fourth warmest winter since national records began in 1895, whereas extremely low temperatures occurred across parts of the Eurasian continent during January 24th-February 14th. This was Europe\'s worst cold spell in at least 26 years, and >650 people died as a result of the frigid conditions in Russia, Ukraine and Poland. A significant amount of snow fell across the affected areas, resulting in the third largest February snow cover extent (Source: NOAA National Climatic Data Center, State of the Climate: Global Analysis for February 2012, published online March 2012, http://www.ncdc.noaa.gov/sotc/global/2012/2). These observations suggest that a negative AO can favor the development of cold weather over Europe and warm weather over North America.

20121月下旬至2月初,喀拉海和拉普捷夫海出现了更广阔的暖心,短暂的负位相AO期间,亚北极欧亚大陆的北部出现了异常的严寒(图1.4b)。北美和欧亚大陆的表面温度距平形成了鲜明的对比。美国经历了自1895年有纪录以来第四暖的冬天,而横跨欧亚大陆的部分在124号至214号经历了极低的温度。这至少是26年来欧洲最严重的寒流,造成650多人死亡,寒冷的条件也发生在俄罗斯、乌克兰和波兰。受影响地区全面降下的显着降雪量,造成第三大的2月积雪范围(来源:NOAA国家气候数据中心于20123月在网上公布的全球气候状况: 20122月分析,http://www .ncdc.noaa.gov/sotc/global/2012/2)。这些结果表明,负位相AO能有利于欧洲寒冷天气和北美温暖天气的发展。
In August 2012, a storm of exceptional intensity affected the Arctic Ocean north of Alaska. The central pressure of 965 hPa made this system one of the strongest August storms to have affected the Arctic Ocean in the past several decades. The storm likely had a significant impact on ocean mixing due to the already reduced sea ice cover, but this remains to be fully evaluated. The storm did have a significant impact on the further retreat of the pack ice, as illustrated in the Sea Ice essay (Fig. 2.5).

20128月,阿拉斯加北部的北冰洋受到特强风暴的影响。中心气压965百帕,在过去几十年里,这是影响北冰洋最强的“八月风暴”系统之一。由于海冰盖已经减少,风暴可能对海洋混合有显着的影响,但这仍有待于全面评估。该风暴还对浮冰的进退有显着的影响,海冰文章所示(图2.5)。


Cloud Cover

云量
Unlike 2011, when Arctic cloud cover was somewhat higher than normal in winter and lower in the summer, Arctic cloud cover in 2012 was, overall, average when compared to the period 2001-2010. However, there were significant monthly anomalies that warrant closer examination, as the spatial patterns varied in important ways on the regional scale.
不像2011年那时的情况, 2012年北极云量与2001年至2010年期间的平均相比,北极云量总体而言,冬季略高于正常和夏季更低于正常。然而,这里有显着靠近实测依据的月度距平,在区域尺度上作为空间格局变化的重要方法和资源。
While clouds influence the surface energy budget, they also respond to changes in the ice cover (Liu et al., 2012). As in recent years, positive cloud cover anomalies (more cloud) over the Arctic Ocean correspond to negative sea ice anomalies (less ice). This was particularly evident in the winter months in the Barents and Kara seas region, and in the summer months from the East Siberian Sea to the Beaufort Sea. An example for February is shown in Figs. 1.7a and b. The reader is referred to the Sea Ice essay for information on Arctic-wide sea ice anomalies during the period 1979-2012.
云量在影响表面能量平衡的同时,他们也对冰盖变化作出反应(Liu等,2012)。近几年来,北冰洋上空的云量正距平(云多),与此对应的海冰负距平(少冰)。这在巴伦支海和喀拉海地区的冬季月份和从东西伯利亚海到波弗特海的夏季月份表现得尤为明显。2月的例子显示在图1.7ab1979年至2012年期间北极海冰距平的信息,读者可以参考海冰文章。
Large-scale advection of heat and moisture and the frequency of synoptic scale systems also influence cloud cover (Liu et al., 2007). Positive cloud anomalies over northern Russia and the Kara Sea in the 2011-2012 winter months correspond to southerly flow on the western side of an anticyclonic pattern, while negative cloud anomalies over Siberia are found on the eastern side of the same pattern (Figs. 1.7 c and d). Positive cloud anomalies over the Chukchi Sea in June (not shown) also appear to be related more to changes in circulation than to changes in sea ice extent. These patterns are also seen in the surface temperature fields (Figs. 1.4b, and c).
热量和水分的大尺度平流与天气尺度系统的频率也会影响云量((Liu等人,2007)。俄罗斯北部的云量正距平和喀拉海在2011-2012年冬季月份对应反气旋西侧偏南气流的模式,而在相同模式东侧的西伯利亚出现云量负距平(图1.7 cd)。与楚科奇海6月(未显示)云量正距平似乎相关的环流变化也大于海冰面积的变化。在表面温度领域中也看到这些模式(图1.4bc)。
ab
cd
Fig. 1.7. Cloud cover (a) and sea ice concentration (b) anomalies (in %) in February 2012 relative to the corresponding monthly means for the period 2002-2010. Data are from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite. Corresponding 500 mb geopotential height (c) and 500 mb wind field (right) anomalies in February 2012 are from NCEP.
图。1.720122月的云量(a)和海冰密集度(b)距平(%),与2002-2010年期间相应月份平均值的比较。 数据来自Aqua卫星上的中分辨率成像光谱仪(MODIS)。对应20122500 MB位势高度场(c)和500 MB风场(右)的距平。来自NCEP
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 楼主| 发表于 2012-12-10 13:48 | 显示全部楼层
(二)
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(三)Carbon Dioxide (CO2) and Methane (CH4)
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