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1.
文章比较了卫星专用传感器微波成像仪/探测仪(SSM/I&SSMIS)、遥感系统数据集(RSS V7R01)、欧洲中期天气预报中心第5代再分析数据(ERA5)和现代回顾分析的研究与应用第2版数据(MERRA-2) 4种观测和再分析资料在刻画全球大洋水汽气候态中的异同点, 初步探究了不同尺度的大气柱水汽总量(TCWV)的变化特征和长期趋势。研究结果表明, 4种数据TCWV的空间分布、季节和年际变化较为一致。从1988至2018年, TCWV总体呈增加趋势, 其中热带海洋的年际变化显著, 增加趋势较强, 且和厄尔尼诺-南方涛动(ENSO)高度相关。利用再分析数据做短时间(如1991—1997年)的TCWV趋势分析时要慎重使用ERA5和MERRA-2的数据。在研究热带区域长期水汽变化趋势时, 需谨慎使用MERRA-2的数据。  相似文献   

2.
再分析风场资料已广泛应用于我国舟山群岛海域可再生能源评估、海洋灾害预防决策以及港口运维和船舶运输等涉海发展领域,然而不同业务机构所提供的再分析数据在舟山近海的性能表现不一,严重阻碍了此类数据的有效应用。基于2018年全年单点浮标观测资料,综合评价了舟山群岛近海面(10 m)风场的长期变化趋势,并利用误差分析和风玫瑰图等统计工具对6种主流海表风场再分析资料,包括:ECMWF第五代全球大气再分析数据(the 5th generation ECMWF atmospheric reanalysis,ERA5)、NECP第二版全球高分辨率再分析数据(climate forecast system version 2,CFSv2)、美国宇航局物理海洋学分布存档中心的多卫星融合资料(cross-calibrated multi-platform,CCMP)、日本55年再分析数据(Japanese 55-year reanalysis,JRA-55)、第二版现代研究与应用回顾性分析数据(modern-era retrospective analysis for research and applications version 2,MERRA-2)和ECMWF哥白尼大气监测服务再分析数据(the Copernicus Atmosphere Monitoring Service,CAMS)在时间变化特征上进行了对比与评估。研究表明:在综合性能方面,ERA5对风场的再现能力最优,其次为JRA-55;在要素可信度方面,ERA5对风速的再现情况相对较优,而CFSv2的风向再现情况较好;风场产品在不同季节的模拟能力有所差异;不同风场产品在不同风速区间的重构能力也有所不同;在全年风向分布方面,各再分析资料都存在显著的东向偏差。研究结果为不同应用场景下风场资料的选取提供评估依据,并为进一步开发适用于舟山群岛近海的高精度长周期风场数据产品奠定基础。  相似文献   

3.
To assess the performances of state-of-the-art global climate models on simulating the Arctic clouds and surface radiation balance, the 2001–2014 Arctic Basin surface radiation budget, clouds, and the cloud radiative effects(CREs) in 22 coupled model intercomparison project 6(CMIP6) models are evaluated against satellite observations. For the results from CMIP6 multi-model mean, cloud fraction(CF) peaks in autumn and is lowest in winter and spring, consistent with that from three satellite observation products(Cloud Sat-CALIPSO, CERESMODIS, and APP-x). Simulated CF also shows consistent spatial patterns with those in observations. However,almost all models overestimate the CF amount throughout the year when compared to CERES-MODIS and APP-x.On average, clouds warm the surface of the Arctic Basin mainly via the longwave(LW) radiation cloud warming effect in winter. Simulated surface energy loss of LW is less than that in CERES-EBAF observation, while the net surface shortwave(SW) flux is underestimated. The biases may result from the stronger cloud LW warming effect and SW cooling effect from the overestimated CF by the models. These two biases compensate each other,yielding similar net surface radiation flux between model output(3.0 W/m~2) and CERES-EBAF observation(6.1 W/m~2). During 2001–2014, significant increasing trend of spring CF is found in the multi-model mean,consistent with previous studies based on surface and satellite observations. Although most of the 22 CMIP6 models show common seasonal cycles of CF and liquid water path/ice water path(LWP/IWP), large inter-model spreads exist in the amounts of CF and LWP/IWP throughout the year, indicating the influences of different cloud parameterization schemes used in different models. Cloud Feedback Model Intercomparison Project(CFMIP)observation simulator package(COSP) is a great tool to accurately assess the performance of climate models on simulating clouds. More intuitive and credible evaluation results can be obtained based on the COSP model output. In the future, with the release of more COSP output of CMIP6 models, it is expected that those inter-model spreads and the model-observation biases can be substantially reduced. Longer term active satellite observations are also necessary to evaluate models' cloud simulations and to further explore the role of clouds in the rapid Arctic climate changes.  相似文献   

4.
The Arctic Oscillation (AO) has important effects on the sea ice change in terms of the dynamic and thermodynamic processes. However, while the dynamic processes of AO have been widely explored, the thermodynamic processes of AO need to be further discussed. In this paper, we use the fifth state-of-the-art reanalysis at European Centre for Medium-Range Weather Forecasts (ERA5) from 1979 to 2020 to investigate the relationship between AO and the surface springtime longwave (LW) cloud radiative forcing (CRF), summertime shortwave (SW) CRF in the Arctic region (65°?90°N). In addition, the contribution of CRF induced by AO to the sea ice change is also discussed. Results indicate that the positive (negative) anomalies of springtime LW CRF and summertime SW CRF are generally detected over the Arctic Ocean during the enhanced positive (negative) AO phase in spring and summer, respectively. Meanwhile, while the LW (SW) CRF generally has a positive correlation with AO index (AOI) in spring (summer) over the entire Arctic Ocean, this correlation is statistically significant over 70°?85°N and 120°W?90°E (i.e., region of interest (ROI)) in both seasons. Moreover, the response of CRF to the atmospheric conditions varies in spring and summer. We also find that the positive springtime (summertime) AOI tends to decrease (increase) the sea ice in September, and this phenomenon is especially prominent over the ROI. The sensitivity study among sea ice extent, CRF and AOI further reveals that decreases (increases) in September sea ice over the ROI are partly attributed to the springtime LW (summertime SW) CRF during the positive AOI. The present study provides a new pattern of AO affecting sea ice change via cloud radiative effects, which might benefit the sea ice forecast improvement.  相似文献   

5.
Gavrikov  A. V.  Gulev  S. K. 《Oceanology》2020,60(6):725-727

We present a high-resolution historical analysis of the atmosphere over the North Atlantic for the period from January 1979 to December 2018. The dataset was obtained using the nonhydrostatic atmospheric model WRF-ARW version 3.8.1 and contains two experiments that differ in spatial resolution: 14 km (HiRes) and 77 km (LoRes). Except for the spatial resolution, the configuration remained identical in both experiments: 50 vertical sigma-levels (starting from ~12 m up to 50 hPa); ERA-Interim reanalysis was used as forcing and spectral nudging. The dataset for HiRes and LoRes experiments was named NAAD (North Atlantic Atmospheric Downscaling). Preliminary results of both HiRes and LoRes reveal good agreement with observations and the ERA-Interim, ERA5, and ASRv2 reanalyses. The NAAD dataset is available online at http://www.naad.ocean.ru and provides a variety of surface and upper-troposphere atmospheric variables with a time step of 3 h.

  相似文献   

6.
北极中央区海冰密集度与云量相关性分析   总被引：2，自引：0，他引：2  
纪旭鹏  赵进平 《海洋学报》2015,37(11):92-104
本文使用海冰密集度以及低云、中云、高云的日平均数据,借助滑动相关分析方法,研究了北极中央区海冰密集度与云量之间的相关性,分析了海冰与云的相互作用机制。研究表明,在春季海冰融化季节(4、5月)、秋季海冰冻结季节(10、11月),低云与海冰密集度之间表现为较好的负相关,表明在这段时间内冰区海面蒸发强烈,对低云的形成有重要贡献。在10月和11月,中云与海冰密集度也有很好的负相关,表明秋季低云可以通过抬升形成中云。高云与海冰密集度之间并没有明显的相关性,可能原因:一方面海冰的空间分布对高云无影响,另一方面,高云主要影响到达的短波辐射,从而影响海冰的融化和冻结速度,与海冰厚度有直接显著的关系,而与海冰密集度的关系不明显。此外,在海冰密集度与低云存在较好负相关的情况下会出现某些年份相关性不好的情况,我们的研究发现这是北极中央区与周边海区发生了海冰交换或云交换的结果。  相似文献   

7.
利用我国第6～9次北极科学考察期间获取的大气探空资料,分析了北极季节冰区边界层逆温的时空变化特征及其成因。分析发现:(1)边界层逆温具有较强的年际变化和空间变化,高纬度密集冰区观测到更多的强逆温现象,逆温厚度与逆温层温差呈显著的对数关系;(2)不同年份边界层逆温的主要成因有所差别:海冰分布的差异导致不同年份的边界层逆温特征不同;表面融化、辐射冷却、多层云的结构和暖平流对不同冰情年份边界层逆温的贡献程度不同;(3)开阔水域和冰区边界层逆温的成因不同。表面融化和空气平流对冰区边界层逆温的形成起着非常重要的作用,而辐射冷却是开阔水域边界层逆温的主要成因之一。  相似文献   

8.
气候模式和再分析数据中北冰洋中层水再现能力的评估   总被引：1，自引：0，他引：1  
The simulations of the Arctic Intermediate Water in four datasets of climate models and reanalyses, CCSM3, CCSM4, SODA and GLORYS, are analyzed and evaluated. The climatological core temperatures and depths in both CCSM models exhibit deviations over 0.5°C and 200 m from the PHC. SODA reanalysis reproduces relatively reasonable spatial patterns of core temperature and depth, while GLORYS, another reanalysis, shows a remarkable cooling and deepening drift compared with the result at the beginning of the dataset especially in the Eurasian Basin(about 2°C). The heat contents at the depth of intermediate water in the CCSM models are overestimated with large positive errors nearly twice of that in the PHC. To the contrary, the GLORYS in 2009 show a negative error with a similar magnitude, which means the characteristic of the water mass is totally lost. The circulations in the two reanalyses at the depth of intermediate water are more energetic and realistic than those in the CCSMs, which is attributed to the horizontal eddy-permitting resolution. The velocity fields and the transports in the Fram Strait are also investigated. The necessity of finer horizontal resolution is concluded again. The northward volume transports are much larger in the two reanalyses, although they are still weak comparing with mooring observations. Finally, an investigation of the impact of assimilation is done with an evidence of the heat input from assimilation. It is thought to be a reason for the good performance in the SODA, while the GLORYS drifts dramatically without assimilation data in the Arctic Ocean.  相似文献   

9.
北极冰海耦合模式对两种不同大气再分析资料响应的分析   总被引：2，自引：2，他引：0  
牟龙江  赵进平 《海洋学报》2015,37(11):79-91
本文中我们比较了Climate Forecast System Reanalysis(CFSR)高分辨率的再分析数据集和低分辨率的Japanese 25-year Reanalysis Project(JRA25)再分析数据集在向下短波辐射、向下长波辐射、10m风场、近地面气温、降水、湿度上的不同,发现二者差异最大的为降水数据,其次为向下短波辐射数据、向下长波辐射数据。用这两个数据集驱动同一冰海耦合模式,CFSR强迫的海冰、北冰洋中层水和加拿大海盆温盐结构与实测相比有很大差距,等密度面上的地转流速在加拿大海盆和欧亚海盆比JRA25强迫的结果高20%,同时等密度面的深度偏深、位温偏高,在弗拉姆海峡的流通量也比海洋再分析数据Simple Ocean Data Assimilation(SODA)偏多。CFSR的向下辐射数据更加接近实测,采用此数据的敏感性实验模拟结果与实测符合的更好。对于海冰的模拟,云量起着至关重要的作用,降水带来的淡水通量通过影响大西洋入流水携带的热量进而影响到冰区。此外,CFSR过量的降水也是二者对于北冰洋温盐结构、弗拉姆海峡流通量以及地转流强度模拟产生偏差的主要原因。尽管风场的分辨率不同,在海盆尺度上对于海冰和海水温盐结构的影响并不大。  相似文献   

10.
本文通过对2001—2017年秋季北极低云的多源数据的分析,展示了本世纪以来北极秋季低云的变化,并为其变化提供了一个新的可能的解释。卫星和再分析数据表明,秋季北极有冰海面低云存在减少的趋势,且在北极边缘海区表现为950 hPa(约500 m)以下近地面云显著减少。本文研究表明,在有冰海面上,低云减少的趋势与背景大气增暖导致的大气相对湿度降低有关,这一关系在80°N以北的北极中央区更明显。而在北极边缘海区,气旋活动对云的影响更重要。在有冰海面,气旋与低云的长期变化趋势相反,两者的年际变化呈负相关关系。利用自组织映射(SOM,Self-Organizing Map)对所有气旋日垂直运动和云分布进行了初步分析,结果表明:在无冰海面和有冰海面由于气旋垂直运动及背景(无气旋日)云分布的差异,气旋对云的影响存在差异。气旋在有冰海面导致低云减少为主,而在无冰海面导致低云增加为主。  相似文献   

11.
Wind-velocity data obtained from in situ measurements at the Golitsyno-4 marine stationary platform have been compared with QuikSCAT scatterometer data; NCEP, MERRA, and ERA-Interim global reanalyses and MM5 regional atmospheric reanalysis. In order to adjust wind velocity measured at a height of 37 m above the sea surface to a standard height of 10 m with stratification taken into account, the Monin–Obukhov theory and regional atmospheric reanalysis data are used. Data obtained with the QuikSCAT scatterometer most adequately describe the real variability of wind over the Black Sea. Errors in reanalysis data are not high either: the regression coefficient varies from 0.98 to 1.06, the rms deviation of the velocity amplitude varies from 1.90 to 2.24 m/s, and the rms deviation of the direction angle varies from 26° to 36°. Errors in determining the velocity and direction of wind depend on its amplitude: under weak winds (<3 m/s), the velocity of wind is overestimated and errors significantly increase in determining its direction; under strong winds (>12 m/s), its velocity is underestimated. The influence of these errors on both spatial and temporal estimates of the characteristics of wind over the Black Sea is briefly considered.  相似文献   

12.
使用ERA-Interim和ERA5两套再分析资料分别驱动东亚区域再分析系统(East Asia Reanalysis System,EARS),并输出2015年一年期试验再分析资料,通过评估其中3次代表性的华南登陆台风降水过程,对比不同驱动场对该系统的影响,研究发现以ERA5驱动的EARS输出结果较ERA-Interim驱动的结果更准确,尤其在丘陵和山地等复杂地形下的降水模拟改进明显。进一步用ERA5驱动的EARS输出结果与欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)新一代陆面再分析资料ERA5-Land对比分析,发现ERA5-Land对于台风大尺度降水的把握更好,而EARS对中小尺度降水过程的再现更完整,特别是对沿海降水的模拟更准确。相较于ERA5-Land,EARS目前同化的观测资料有限,对物理过程参数化方案的选择仍欠准确,后续需要有针对性地改进。  相似文献   

13.
Sediment-laden sea ice is widespread over the shallow, wide Siberian Arctic shelves, with off-shelf export from the Laptev and East Siberian Seas contributing substantially to the Arctic Ocean's sediment budget. By contrast, the North American shelves, owing to their narrow width and greater water depths, have not been deemed as important for basin-wide sediment transport by sea ice. Observations over the Chukchi and Beaufort shelves in 2001/02 revealed the widespread occurrence of sediment-laden ice over an area of more than 100,000 km2 between 68 and 74°N and 155 and 170°W. Ice stratigraphic studies indicate that sediment inclusions were associated with entrainment of frazil ice into deformed, multiple layers of rafted nilas, indicative of a flaw-lead environment adjacent to the landfast ice of the Chukchi and Beaufort Seas. This is corroborated by buoy trajectories and satellite imagery indicating entrainment in a coastal polynya in the eastern Chukchi Sea in February of 2002 as well as formation of sediment-laden ice along the Beaufort Sea coast as far eastward as the Mackenzie shelf. Moored upward-looking sonar on the Mackenzie shelf provides further insight into the ice growth and deformation regime governing sediment entrainment. Analysis of Radarsat Synthetic Aperture (SAR) imagery in conjunction with bathymetric data help constrain the water depth of sediment resuspension and subsequent ice entrainment (>20 m for the Chukchi Sea). Sediment loads averaged at 128 t km–2, with sediment occurring in layers of roughly 0.5 m thickness, mostly in the lower ice layers. The total amount of sediment transported by sea ice (mostly out of the narrow zone between the landfast ice edge and waters too deep for resuspension and entrainment) is at minimum 4×106 t in the sampling area and is estimated at 5–8×106 t over the entire Chukchi and Beaufort shelves in 2001/02, representing a significant term in the sediment budget of the western Arctic Ocean. Recent changes in the Chukchi and Beaufort Sea ice regimes (reduced summer minimum ice extent, ice thinning, reduction in multi-year ice extent, altered drift paths and mid-winter landfast ice break-out events) have likely resulted in an increase of sediment-laden ice in the area. Apart from contributing substantially to along- and across-shelf particulate flow, an increase in the amount of dirty ice significantly impacts (sub-)ice algal production and may enhance the dispersal of pollutants.  相似文献   

14.
北极中央区海冰低密集度现象研究   总被引：3，自引：3，他引：0  
近年，北极中央密集冰区出现海冰低密集度的异常现象。为了探讨这一现象的成因，本文使用ERA-Interim再分析资料，定义了北极中央区海冰低密集度（LCCA）指数，研究了2009-2016年的6-9月北极中央区发生的海冰低密集度现象。分析表明，研究时段内在北极中央区发生了6次明显的海冰低密集度（LCCA峰值）过程。在这些过程中，局地气温异常并不是导致海冰低密集度现象发生最主要的因素；海冰低密集度区域的形态及冰速场分布均与大气环流场相对应；在LCCA指数峰值发生前均有气旋中心出现在北冰洋70°N以北并伴随向北移动，气旋引起海冰辐散，同时所携带的较低纬度的热量导致海冰迅速融化。在6次过程中，有3次为气旋影响配合北极偶极子（DA）型环流。LCCA指数与84°N平均向北温度平流和北极中央区海冰速度散度呈正相关。在LCCA指数峰值前，温度平流对海冰低密集度区域形成的影响大于海冰辐散的影响。  相似文献   

15.
李江夏  朱钰  徐杰  姚宇 《海洋通报》2023,(3):260-271
全球再分析海面风资料在波浪模拟和风能资源评估等研究中发挥着重要作用，但风场资料种类繁多，且准确性在不同海域差异较大，使用时需要进行适用性分析。本文基于欧洲中期天气预报中心的ERA5和ERA-Interim再分析风场，利用多个站点的实测数据，分析了其在中国近海的适用性，并将再分析风场输入FVCOM-SWAVE波浪模型，对比了它们在常风天和台风天对波浪模拟的效果。结果表明：（1）常风天条件下ERA5和ERA-Interim资料在中国近海表现相似，风速较实测值略偏大，均能基本反映海表面风场变化和平均风速分布，吻合度指标在各站点均超过0.9;(2) ERA5对台风的模拟显著优于ERA-Interim，能较好模拟台风风速结构，对不同台风模拟精度差异大，整体上会低估台风风速；（3）风场质量是造成波浪模拟误差的主要原因之一，ERA5和ERA-Interim均能较好地模拟常海况下的波浪变化情况，而在台风浪的模拟中ERA5更优，“双台风”现象对风速和波浪的模拟准确度影响大。  相似文献   

16.
2017年夏季中国第八次北极科学考察期间，"雪龙"号极地考察船首次成功穿越北极中央航道，期间全程开展了海冰要素的人工观测。中央航道走航期间的平均海冰密集度和平均冰厚分别为0.64和1.5 m，海冰密集度时空变化大且以厚当年冰为主，高纬密集冰区的浮冰大小显著高于海冰边缘区。基于"雪龙"号的船基走航观测海冰密集度评估比较了国际上常用的5种常用的微波遥感反演海冰密集度产品，同走航目测海冰密集度点对点的比较，误差最大的为德国不来梅大学AMSR2基于Bootstrap算法的产品，平均误差和均方根误差分别为0.19和0.28；误差最小的为欧洲气象卫星应用组织基于AMSR2数据和OSHD和TUD两种不同算法的产品，平均误差分别为-0.02和0.01，均方根误差均为0.20。从日平均比较来看，AMSR2基于Bootstrap算法的误差最大，平均误差和均方根误差分别为0.15和0.20；AMSR2/OSI SAF（TUD）的误差最小，平均误差和均方根误差分别为0.0和0.11，OSI SAF产品更接近人工观测结果。  相似文献   

17.
Long term in situ atmospheric observation of the landfast ice nearby Zhongshan Station in the Prydz Bay was performed from April to November 2016. The in situ observation, including the conventional meteorological elements and turbulent flux, enabled this study to evaluate the sea ice surface energy budget process. Using in situ observations, three different reanalysis datasets from the European Centre for Medium-Range Weather Forecasts Interim Re-analysis(ERA-Interim), National Centers for Environmental Prediction Reanalysis2(NCEP R2), and Japanese 55-year Reanalysis(JRA55), and the Los Alamos sea ice model, CICE, output for surface fluxes were evaluated. The observed sensible heat flux(SH) and net longwave radiation showed seasonal variation with increasing temperature. Air temperature rose from the middle of October as the solar elevation angle increased.The ice surface lost more energy by outgoing longwave radiation as temperature increased, while the shortwave radiation showed obvious increases from the middle of October. The oceanic heat flux demonstrated seasonal variation and decreased with time, where the average values were 21 W/m~2 and 11 W/m~2, before and after August,respectively. The comparisons with in situ observations show that, SH and LE(latent heat flux) of JRA55 dataset had the smallest bias and mean absolute error(MAE), and those of NCEP R2 data show the largest differences.The ERA-Interim dataset had the highest spatial resolution, but performance was modest with bias and MAE between JRA55 and NCEP R2 compare with in situ observation. The CICE results(SH and LE) were consistent with the observed data but did not demonstrate the amplitude of inner seasonal variation. The comparison revealed better shortwave and longwave radiation stimulation based on the ERA-Interim forcing in CICE than the radiation of ERA-Interim. The average sea ice temperature decreased in June and July and increased after September,which was similar to the temperature measured by buoys, with a bias and MAE of 0.9°C and 1.0°C, respectively.  相似文献   

18.
This paper evaluates the impact of using different wind field products on the performance of the third generation wave model SWAN in the Black Sea and its capability for predicting both normal and extreme wave conditions during 1996. Wind data were obtained from NCEP CFSR, NASA MERRA, JRA-25, ECMWF Operational, ECMWF ERA40, and ECMWF ERA-Interim. Wave data were obtained in 1996 at three locations in the Black Sea within the NATO TU-WAVES project. The quality of wind fields was assessed by comparing them with satellite data. These wind data were used as forcing fields for the generation of wind waves. Time series of predicted significant wave height (Hmo), mean wave period (Tm02), and mean wave direction (DIR) were compared with observations at three offshore buoys in the Black Sea and its performance was quantified in terms of statistical parameters. In addition, wave model performance in terms of significant wave height was also assessed by comparing them against satellite data.The main scope of this work is the impact of the different available wind field products on the wave hindcast performance. In addition, the sensitivity of wave model forecasts due to variations in spatial and temporal resolutions of the wind field products was investigated. Finally, the impact of using various wind field products on predicting extreme wave events was analyzed by focussing on storm peaks and on an individual storm event in October 1996. The numerical results revealed that the CFSR winds are more suitable in comparison with the others for modelling both normal and extreme events in the Black Sea. The results also show that wave model output is critically sensitive to the choice of the wind field product, such that the quality of the wind fields is reflected in the quality of the wave predictions. A finer wind spatial resolution leads to an improvement of the wave model predictions, while a finer temporal resolution in the wind fields generally does not significantly improve agreement between observed and simulated wave data.  相似文献   

19.
The dramatic decline of summer sea ice extent and thickness has been witnessed in the western Arctic Ocean in recent decades, which hasmotivated scientists to search for possible factors driving the sea ice variability. An eddy-resolving, ice-ocean coupled model covering the entire Arctic Ocean is implemented, with focus on the western Arctic Ocean. Special attention is paid to the summer Alaskan coastal current (ACC), which has a high temperature (up to 5℃ ormore) in the upper layer due to the solar radiation over the open water at the lower latitude. Downstream of the ACC after Barrow Point, a surface-intensified anticyclonic eddy is frequently generated and propagate towards the Canada Basin during the summer season when sea ice has retreated away from the coast. Such an eddy has a warm core, and its source is high-temperature ACC water. A typical warm-core eddy is traced. It is trapped just below summer sea ice melt water and has a thickness about 60 m. Temperature in the eddy core reaches 2-3℃, and most water inside the eddy has a temperature over 1℃. With a definition of the eddy boundary, an eddy heat is calculated, which can melt 1 600 km2 of 1mthick sea ice under extreme conditions.  相似文献   

20.
Statistical characteristics of major and minor sudden stratospheric warmings (SSWs) in the Northern Hemisphere (NH) for 1958–2015 are analyzed using data of NCEP-NCAR, ERA 40, and ERA-Interim reanalyses. Dependencies of the number of major SSWs with the displacement of the circumpolar stratospheric vortex and the number of minor SSWs on the phase of the quasi-biennial oscillation (QBO) of the equatorial stratospheric wind and on the level of solar activity (SA) in the 11-year solar cycle have been revealed. Major SSWs accompanied by a displacement of the polar vortex occur more often at a high level of SA and at the easterly phase of the QBO in the 50–40 hPa layer, while minor SSWs occur more often at a low SA level and at the westerly phase of the QBO. An analysis of spatiotemporal dynamics of the stratospheric polar vortex at major SSWs is performed. The most probable directions of vortex displacement caused by SSWs have been revealed. Influences of the major SSWs on the total contents of NO2 and ozone, as well as on stratosphere temperature, are analyzed.  相似文献   

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