• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Change of Arctic sea-ice volume and its relationship with sea-ice extent in CMIP5 simulations

    2016-11-23 01:12:53SONGMiRong
    關(guān)鍵詞:北極海覆蓋范圍海冰

    SONG Mi-Rong

    State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics,Chinese Academy of Sciences, Beijing, China

    Change of Arctic sea-ice volume and its relationship with sea-ice extent in CMIP5 simulations

    SONG Mi-Rong

    State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics,Chinese Academy of Sciences, Beijing, China

    The future change of September Arctic sea-ice volume, simulated by 30 state-of-the-art climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5), is examined, which depends on both ice extent and ice thickness. In comparison with the September sea-ice extent,the September sea-ice volume has larger spread in the historical simulation but faster convergence in the projection simulation, especially in the context of increasing greenhouse gas emissions. This indicates that the ice volume might be more sensitive to external forcings than the ice extent. Using the averaged projection of those climate models from the 30 CMIP5 models that can better reflect the ‘observed' sea-ice volume climatology and variability, it is shown that the September sea ice volume will decrease to ~3000 km3in the early 2060s, and then level off under a medium-mitigation scenario. However, it will drop to ~3000 km3in the early 2040s and reach a near-zero ice volume in the mid-2070s under a high-emission scenario. With respect to the historical condition, the reduction of the ice volume, associated with increasing greenhouse gas emissions, is more rapid than that of the ice extent during the twenty-first century.

    ARTICLE HISTORY

    Accepted 11 August 2015

    Sea-ice volume; sea-ice extent; sea-ice thickness;CMIP5

    由于對(duì)未來(lái)北極海冰體積的變化研究相對(duì)較少,本文利用多模式比較計(jì)劃模擬的海冰結(jié)果,對(duì)北極9月海冰體積及其與海冰覆蓋范圍的關(guān)系進(jìn)行了分析。結(jié)果發(fā)現(xiàn),相對(duì)于海冰覆蓋范圍,多模式模擬得到的北極海冰體積的差異跨度更大,但這種差異跨度隨著時(shí)間的演變迅速減小,表明海冰體積可能是比海冰覆蓋范圍更為敏感的因子。同時(shí)少數(shù)幾個(gè)能夠更加合理反映觀測(cè)的海冰特征與變化的模式的模擬結(jié)果顯示,在高排放情景下,北極海冰在本世紀(jì)70年代時(shí),基本達(dá)到了無(wú)冰的狀態(tài)。

    Introduction

    The Arctic sea-ice volume (area multiplied by thickness)is an important indicator of climate change. In general,sea-ice volume is less susceptible to particular weather events (i.e. storms) than sea-ice extent (Schweiger et al. 2011; Zygmuntowska et al. 2014). Moreover, sea-ice volume might be more closely tied to climate forcings than sea-ice extent, i.e. sea-ice extent may still have considerable variability even when the Arctic Ocean reaches near ice-free conditions, whereas sea-ice volume variability is small. Associated with the rapid decline of summer Arctic sea-ice extent in the past three decades (Serreze,Holland, and Stroeve 2007; Comiso et al. 2008), the combined records from submarine measurements and the Ice, Cloud, and land Elevation Satellite (ICESat) show that mean summer Arctic sea-ice thickness has decreased by about 1.65 m (from 2.80 m in 1980 to 1.15 m in 2007)(Rothrock, Yu, and Maykut 1999; Kwok and Rothrock 2009;Kwok and Untersteiner 2011). Moreover, the abrupt seaice reductions since 2007 have further contributed to the overall dramatic decrease in the ice thickness. This is reflected by the pronounced decrease of the perennial(multi-year) sea ice and the increasing coverage of seasonal (first-year) sea ice in the Arctic Ocean (Maslanik et al. 2007, 2011; Giles et al. 2008). Decline in sea-ice extent and thickness leads to a reduction of sea-ice volume. Arctic sea-ice volume estimated from the Pan Arctic Ice Modeling and Assimilation System (PIOMAS, Schweiger et al. 2011) shows that the September ice volume has decreased by ~75% from 1979 to 2011 (thick black line in Figure 1), which outpaces the decrease of September ice extent (~36% from 1979 to 2011). This indicates that seaice volume may be a more sensitive indicator of climate change than sea-ice extent.

    Figure 1.Time series of the observed (thick black line) and simulated (colored lines) September sea-ice volume of 30 CMIP5 models from 1979 to 2005 in the historical simulation and from 2006 to 2099 under the (a) RCP4.5 and (b) RCP8.5 scenarios (the thick brown line is the multi-model ensemble mean).

    Several studies have been conducted recently describing the future change of Arctic sea-ice extent during the twenty-first century using the recent available simulations from Coupled Model Intercomparison Project Phase 5(CMIP5) (e.g. Massonnet et al. 2012; Stroeve et al. 2012;Wang and Overland 2012; Liu et al. 2013). A few studies have looked into Arctic sea-ice thickness; for instance,Langehaug et al. (2013) evaluated the Fram Strait ice area export and its influence on Arctic sea-ice area and thickness using historical simulations of six CMIP5 models. However,relatively little attention has been paid to the simulated ice volume in CMIP5. The present study focuses mainly on the future change of Arctic sea-ice volume and its relationship with Arctic sea-ice extent, providing insights to further our understanding of sea-ice simulations and projections in CMIP5.

    Data

    Figure 2.Evolution of 30 CMIP5 models' spread for the September Arctic sea-ice volume and extent during 1979-2005.

    This study focuses on September sea ice (all the grid cells covered by sea ice in the Northern Hemisphere are included), given that the seasonal minimum of Arctic sea ice is in September, and Arctic shipping has increased as sea ice has decreased dramatically. The coordinated CMIP5 climate change experiments (Taylor, Stouffer, and Meehl 2012; Knutti and Sedlá?ek 2013; Sillmann et al. 2013) provide new perspectives that aid understanding and studies of present and future climate. Here, 30 CMIP5 models are analyzed (the first ensemble member for each model achieved on the Program for Climate Model Diagnosis and Intercomparison (PCMDI) data portal), including both historical simulations that end in 2005 and projection simulations under the +4.5 and +8.5 W m-2Representative Concentration Pathway (RCP4.5 and RCP8.5, respectively)scenarios from 2006 to 2099. The reanalysis of sea-ice volume during 1979-2011 from the recently updated PIOMAS is used in this study as the ‘observation', since there are no long-term and spatially homogenous sea-ice thickness observations, which improves on prior versions by assimilating sea surface temperatures for ice-free areas and by using a different parameterization for the strength of the ice (Schweiger et al. 2011). Note that the PIOMAS ice volume has uncertainty (a coupled sea-ice-ocean model constrained by the assimilation of sea-ice concentration and sea surface temperature), even though the spatial pattern of the PIOMAS ice thickness resembles the ICESat observation (Schweiger et al. 2011), and the seasonal cycle of the PIOMAS ice volume is largely consistent with the recent CryoSat2 observation (Laxon et al. 2013). Seaice extent data are from the National Snow and Ice Data Center (NSIDC) (Fetterer et al. 2009). Since most of the historical simulations end in 2005, the data for 2006-11 from the RCP4.5 runs are used to extend the time series where necessary.

    Results and discussion

    Figure 1 shows the evolution of September sea-ice volume from 1979 to 2099 simulated by 30 CMIP5 models. The inter-model spread in the simulated September sea-ice volume is very large (i.e. from 2.42 × 103to 36.21 × 103km3in 1979). Some individual models (e.g. ACCESS1.3, CESM1-BGC) capture the rapid decline of the Arctic September sea-ice volume after 2007. The September sea-ice volume trend of the multi-model mean during 1979-2011 is -7.22 × 103km3, and the corresponding observed ice volume trend is -10.28 × 103km3. Since the multi-model mean primarily represents the external forcing effect (Kay et al. 2011), it gives a rough estimate of 70% of the anthropogenic contribution to the September ice volume decline rate from 1979 to 2011. This forced contribution factor is close to 97% for the September sea-ice volume from 1979 to 2005, which is much stronger than the forced contribution of 56% for the September sea-ice extent during 1979-2005 (Kay, Holland, and Jahn 2011).

    For each year in the historical simulation (1979-2005;CMIP5 historical simulation ends in 2005), the absolute bias is calculated for the September sea-ice volume between the simulation of each individual CMIP5 model and the observation, and the 30 biases are averaged. The standard deviation of the observed sea-ice volume during 1979-2005 is also calculated. Then, the averaged bias is divided by the observed standard deviation, which represents the modeled ice volume spread in CMIP5. The calculation is also repeated for the simulated and observed September sea-ice extent. Note that the spreads of the simulated ice volume and extent are normalized so that they can be compared directly.

    Figure 3.Evolution of the standard deviation of the simulated September sea-ice volume (SepSIV, red) and extent (SepSIE, blue) for 30 models during 1979-2099 with respect to PIOMAS SepSIV and NSIDC SepSIE standard deviation of 1979-2005, respectively, under (a)RCP4.5 and (b) RCP8.5.

    As shown in Figure 2, the averaged difference between the simulated September ice volume and observed September ice volume is four times the interannual variability of the volume observation at the beginning (the late 1970s). By contrast, the averaged difference between the simulated September ice extent and observed September sea-ice extent is two times the interannual variability of the extent observation at the beginning. Compared with the September sea-ice extent, the September sea-ice volume has larger spread in the historical simulations of the 30 CMIP5 models, which is mainly attributed to the large spread of simulated sea-ice thickness. With time, the averaged difference of the ice volume gradually decreases and,in 2005, the difference is ~2.8 times the observed interannual variability, but no obvious change is found for the averaged difference of the ice extent during 1979-2005. This implies that the thinning of sea-ice thickness during 1979-2005 tends to reduce the spread in the simulated sea-ice thickness, which is not the case for sea-ice extent. Given that the models could not capture the observed year-to-year variability in an uninitialized long-term simulation, the simulated September ice volume standard deviation of the 30 CMIP5 models is also calculated for each year (i.e. 1979, 1980, 1981, … , 2099), and divided by the standard deviation of PIOMAS September sea-ice volume during 1979-2005, as illustrated in Figure 3. The calculation is also repeated for the simulated and observed September ice extent. It almost reproduces the evolution in Figure 2 when using a different definition to quantify the model spread, which certifies a robust result for evaluating the model spread.

    Additionally, the simulated September ice volume shows a faster convergence towards the late twenty-first century than that of the September ice extent for both RCP4.5 and RCP8.5 (Figure 3). The anthropogenic forcing steadily increases from 2005 to 2069 and then becomes stabilized for the RCP4.5 runs, while it shows a sustained increase for the RCP8.5 runs (also Hezel et al. (2014), Figure 1). As shown in Figure 3, from the late 1970s to 2040s, the model spread of the projected September sea-ice extent expands gradually as the Arctic sea ice declines, which shows good agreement with the anthropogenic forcing change for both emissions scenarios, while the modeledSeptember sea-ice volume spread continues to shrink rapidly. By contrast, from the 2050s, the ice extent spread tends to oscillate around 3.5 for RCP4.5, and turns to converge for RCP8.5, while the ice volume spread continues to decrease until ~2070 (~2080) under the RCP4.5 (RCP8.5) scenario, and then oscillates slightly toward the end of the twenty-first century. Thus, the decrease of the ice volume spread is a consequence of both the declining ice extent spread and ice thickness spread. Meanwhile, the consistent signal of shrinking spread under both the RCP4.5 andRCP8.5 scenarios indicates that the September ice volume is a more robust sensor to the forcings.

    Figure 4.(a) Climatology (average) and (b) linear trend of September sea-ice volume for the ‘observation' (black bar on left) and each CMIP5 model (gray bars) during 1979-2011 (the second to last black bar on right-hand side is the ensemble mean of the four selected models, while the right-most bar is the ensemble mean of all 30 models).

    Figure 5.Time series of the observed (thick black line) and simulated (colored lines) September sea-ice volume of four selected CMIP5 models from 1979 to 2005 in the historical simulation and from 2006 to 2099 under the (a) RCP4.5 and (b) RCP8.5 scenarios (the thick brown line is the four-model ensemble mean).

    Figure 6.Evolution of the ratio between the proportional reduction in the simulated September sea-ice volume and extent (averaged for the sliding five-year windows) with respect to 1979 for the four selected models under the RCP4.5 (solid line) and RCP8.5 (dashed line)scenarios. The black dot is the ratio for the present state (2007-11) with respect to 1979.

    Nonetheless, large spread exists regarding the simulation of September Arctic sea-ice volume. Credible projection of future change in Arctic sea-ice volume is strongly built on the CMIP5 models' abilities to reproduce the observed climatology and variability of sea-ice volume. Using similar methods to those proposed by Liu et al. (2013), the models with the simulated September sea ice volume falling within one standard deviation of the observed September ice volume during 1979-2011 (two gray lines in Figure 4a) are first selected. The corresponding time range is the combination of 1979-2005 for the historical simulation and 2006-11 under the medium-mitigation scenario. Eight of the 30 CMIP5 models satisfy that requirement (ACCESS1.3, BNU-ESM, CCSM4, CESM1-BGC, FIO-ESM, GFDL-CM3, HADGEM2-CC and HADGEM2-ES; Figure 4a). Furthermore, those models with the simulated trend of September sea-ice volume falling within one standard deviation of the observed September ice volume during 1979-2011 are retained and superimposed on the observed trend (two gray lines in Figure 4b). Nine of the 30 CMIP5 models satisfy that requirement (ACCESS1.3, CCSM4,CESM1-BGC, CESM1-CAM5, FGOALS-G2, HADGEM2-CC,IPSL-CM5A.LR, IPSL-CM5A.MR, and NORESM1-M; Figure 4b). The four models that meet both the climatology and trend criteria are ultimately retained. They are: ACCESS1.3,CCSM4, CESM1-BGC, and HADGEM2-CC. The climatology and trend of September sea-ice volume for the ensemble mean of the four models during 1979-2011 are in good agreement with the observation. Compared with the result from the 30-model ensemble mean, an obvious improvement based on the four selected models is reflected in the simulated Arctic sea-ice volume trend in September. Note that, using similar methods to those proposed by Liu et al. (2013), three models (ACCESS1.3, CESM1-BGC, and HADGEM2-CC) of the four selected models in this study based on the ice volume are the same as those in Liu et al.(2013) based on the ice extent. This suggests that the ice volume and extent reflect different ice state evolutions,although they are interrelated.

    The ensemble mean of the four models shows that,under the RCP4.5 scenario, the simulated September seaice volume decreases to ~3000 km3(~25% of the observed September ice volume averaged during 1979-2011) in the early 2060s, and then tends to level off towards the end of the twenty-first century after the forcing stabilizes. By contrast, under RCP8.5, the simulated September seaice volume drops to ~3000 km3in the early 2040s, which is almost two decades earlier than under RCP4.5, and approaches zero in the mid-2070s (Figure 5). This is consistent with recent studies showing that the Arctic may reach an ice-free state in the middle of the twenty-first century under RCP8.5 (Massonnet et al. 2012; Liu et al. 2013), while under RCP4.5 the September Arctic sea ice decreases until early in the 2060s when it starts to level off.

    Since 2007, the observed September Arctic sea-ice volume has decreased much faster (thick black line in Figure 1) than that of 1979-2006. The PIOMAS estimate shows that the averaged September sea-ice volume for the new low ice-cover state (2007-2011) has decreased by~65.1% with respect to 1979, which is double the speed of decrease of the September sea-ice extent (the averaged September ice extent for 2007-2011 has decreased by~33.4% with respect to 1979). As shown in Figure 6, the relationship between the proportional reduction in simulated September sea-ice volume and extent throughout the twenty-first century is not linear. Here, the proportional reduction is defined as follows: (1) Compute the mean September sea-ice volume (extent) of the four selected models for each year from 2008 to 2099. (2) Based on the results from (1), compute the five-year mean of 2008-12,2009-13, 2010-14, and so on. (3) Compute the rate of decrease of the five-year mean ice volume (extent) relative to 1979. (4) Finally, compute the ratio of the ice volume rate of decrease to the ice extent rate of decrease. Under the RCP4.5 scenario, the proportional reduction of the ice volume is nearly two times that of the ice extent at thebeginning of the twenty-first century, which is consistent with the observation. The ratio decreases to ~1.2-1.3 in the early 2060s, and then tends to oscillate around ~1.2-1.3 towards the end of the twenty-first century. It reflects a more rapid decline of the ice volume than that of the ice extent before the early 2060s. Since the ratio primarily reflects the ensemble mean evolution of the ice thickness,it implies that the basin-wide average ice thickness tends to level off in the early 2060s. By contrast, under the RCP8.5 scenario, the ratio decreases to ~1.2-1.3 in the early 2040s,and approaches ~1 in the early 2070s. The timings of these ratio changes (Figure 6, which mainly reflects the averaged sea-ice thickness change) are in good agreement with the aforementioned spread variations (Figure 3) in RCP4.5 and RCP8.5.

    Conclusions

    This study identifies (1) significantly larger spread regarding September sea-ice volume forced by anthropogenic and natural forcings, as compared to September sea-ice extent, as shown in the historical simulations, and (2)greater sensitivity regarding September sea-ice volume in response to the increase in greenhouse gas emissions relative to September sea-ice extent, as shown in the projection simulations. These impose further challenges to achieve accurate simulation of Arctic sea-ice volume as the climate warms.

    The model selection described in this study reduces the spread in the projected September sea-ice volume under both emissions scenarios. A quantitative analysis of the ice volume and extent reduction using the selected models is implemented, and it indicates that, with respect to the historical condition, the reduction of the ice volume,associated with increasing greenhouse gas emissions, is more rapid than that of the ice extent during the twenty-first century. The ratio evolution (expressing the relation between the reduction in sea-ice volume and sea-ice extent) is in quite good agreement with the anthropogenic forcing variations in both RCP4.5 and RCP8.5. Firstly, the ratio decreases from ~2.0 in the early 2010s to 1.2-1.3 in the early 2060s, then becomes persistent around 1.2,under the RCP4.5 scenario. Secondly, the ratio decreases from ~1.9 at the beginning of the 2010s to near 1 by the end of twenty-first century, under the RCP8.5 scenario. The transition from large to small ratio indicates that the Arctic sea-ice state is changing. Thus, better understanding the evolution of the ratio between the proportional reduction of observed September sea-ice volume and extent may provide us with further clues on the future change of Arctic sea ice.

    Moreover, the rapid loss of Arctic sea ice in recent years provides further evidence that Arctic sea ice has entered a new regime of thinner and predominantly first-year ice. Given the discrepancy between the simulated and observed ice volume and rapid change of sea ice, we need to improve the radiative interactions among the atmosphere, sea ice and ocean (positive feedbacks),and poleward oceanic and atmospheric heat transports(potential negative feedback) in climate models, as they play important roles in the simulation of Arctic sea-ice volume. Better representation of these processes, leading to reasonable simulation of Arctic sea-ice volume in response to anthropogenic and natural forcings, is a priority for the accurate prediction of how Arctic sea ice might change in the near future.

    Acknowledgments

    Thanks and appreciation are extended to the climate modeling groups all across the world, the WCRP Working Group on Coupled Modeling, and the Program for Climate Model Diagnosis and Intercomparison, for making the CMIP5 model outputs available.

    Funding

    This research was supported by the National Natural Science Foundation of China [grant numbers 41305097 and 41176169],the National Basic Research Program of China [973 program,grant number 2011CB309704].

    References

    Comiso, J. C., C. L. Parkinson, R. Gersten, and L. Stock. 2008.“Accelerated Decline in the Arctic Sea Ice Cover.” Geophysical Research Letters 35: L01703.

    Fetterer, F., K. Knowles, W. Meier, and M. Savoie. 2009. Sea Ice Index [1979-2011]. Boulder, CO: National Snow and Ice Data Center. http://nsidc.org/data/G02135.

    Giles, K. A., S. W. Laxon, and A. L. Ridout. 2008. “Circumpolar Thinning of Arctic Sea Ice following the 2007 Record Ice Extent Minimum.” Geophysical Research Letters 35: L22502.

    Hezel, P. J., T. Fichefet, and F. Massonnet. 2014. “Modeled Arctic Sea Ice Evolution through 2300 in CMIP5 Extended RCPs.” The Cryosphere 8: 1195-1204.

    Kay, J. E., M. M. Holland, and A. Jahn. 2011. “Inter-annual to Multi-decadal Arctic Sea Ice Extent Trends in a Warming World.” Geophysical Research Letters 38: L15708.

    Knutti, R., and J. Sedlá?ek. 2013. “Robustness and Uncertainties in the New CMIP5 Climate Model Projections.” Nature Climate Change 3: 369-373.

    Kwok, R., and D. Rothrock. 2009. “Decline in Arctic Sea Ice Thickness from Submarine and ICESat Records: 1958-2008.”Geophysical Research Letters 36: L15501.

    Kwok, R., and N. Untersteiner. 2011. “The Thinning of Arctic Sea Ice.” Physics Today 64 (4): 36-41.

    Langehaug, H. R., F. Geyer, L. H. Smedsrud, and Y. Gao. 2013.“Arctic Sea Ice Decline and Ice Export in the CMIP5 Historical Simulations.” Ocean Modelling 71: 114-126.

    Laxon, S. W., K. A. Giles, A. L. Ridout, D. J. Wingham, R. Willatt, R.Cullen, R. Kwok, A. Schweiger, J. Zhang, and C. Haas. 2013.“CryoSat-2 Estimates of Arctic Sea Ice Thickness and Volume.”Geophysical Research Letters 40 (4): 732-737.

    Liu, J. P., M. R. Song, R. M. Horton, and Y. Y. Hu. 2013. “Reducing Spread in Climate Model Projections of a September Ice-Free Arctic.” Proceedings of the National Academy of Sciences of the United States of America 110: 12571-12576.

    Maslanik, J., C. Fowler, J. Stroeve, S. Drobot, J. Zwally, D. Yi, and W. Emery. 2007. “A Younger, Thinner Arctic Ice Cover: Increased Potential for Rapid, Extensive Sea-Ice Loss.” Geophysical Research Letters 34: L24501.

    Maslanik, J., J. Stroeve, C. Fowler, and W. Emery. 2011.“Distribution and Trends in Arctic Sea Ice Age through Spring 2011.” Geophysical Research Letters 38: L13502.

    Massonnet, F., T. Fichefet, H. Goosse, C. M. Bitz, G. Philippon-Berthier, M. M. Holland, and P. Y. Barriat. 2012. “Constraining Projections of Summer Arctic Sea Ice.” Cryosphere 6: 1383-1394. Rothrock, D. A., Y. Yu, and G. A. Maykut. 1999. “Thinning of the Arctic Sea-Ice Cover.” Geophysical Research Letters 26: 3469-3472.

    Schweiger, A., R. Lindsay, J. L. Zhang, M. Steele, H. Stern, and R. Kwok. 2011. “Uncertainty in Modeled Arctic Sea Ice Volume.”Journal of Geophysical Research-Oceans 116: C00D06.

    Serreze, M. C., M. M. Holland, and J. Stroeve. 2007. “Perspectives on the Arctic's Shrinking Sea-Ice Cover.” Science 315: 1533-1536.

    Sillmann, J., V. V. Kharin, X. Zhang, F. W. Zwiers, and D. Bronaugh. 2013. “Climate Extremes Indices in the CMIP5 Multimodel Ensemble: Part 1. Model Evaluation in the Present Climate.”Journal of Geophysical Research-Atmospheres 118: 1716-1733. Stroeve, J. C., V. Kattsov, A. Barrett, M. Serreze, T. Pavlova, M. Holland, and W. N. Meier. 2012. “Trends in Arctic Sea Ice Extent from CMIP5, CMIP3 and Observations.” Geophysical Research Letters 39: L16502.

    Taylor, K. E., R. J. Stouffer, and G. A. Meehl. 2012. “An Overview of CMIP5 and the Experiment Design.” Bulletin of the American Meteorological Society 93: 485-498.

    Wang, M. Y., and J. E. Overland. 2012. “A Sea Ice Free Summer Arctic within 30 Years: An Update from CMIP5 Models.”Geophysical Research Letters 39: L18501.

    Zygmuntowska, M., P. Rampal, N. Ivanova, and L. H. Smedsrud. 2014. “Uncertainties in Arctic Sea Ice Thickness and Volume: New Estimates and Implications for Trends.” The Cryosphere 8: 705-720.

    7 May 2015

    CONTACT SONG Mi-Rong songmirong@lasg.iap.ac.cn

    ? 2016 The Author(s)

    This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

    猜你喜歡
    北極海覆蓋范圍海冰
    末次盛冰期以來(lái)巴倫支海-喀拉海古海洋環(huán)境及海冰研究進(jìn)展
    基于機(jī)器學(xué)習(xí)的基站覆蓋范圍仿真
    基于SIFT-SVM的北冰洋海冰識(shí)別研究
    工傷社會(huì)保險(xiǎn)覆蓋范圍的擴(kuò)展及其路徑
    淺談提高小功率短波電臺(tái)覆蓋范圍的措施
    電子制作(2016年23期)2016-05-17 03:54:06
    關(guān)于短波廣播覆蓋范圍的幾點(diǎn)探討
    科技視界(2016年9期)2016-04-26 09:14:10
    累積海冰密集度及其在認(rèn)識(shí)北極海冰快速變化的作用
    中部型El Nino與北極海冰變化的聯(lián)系
    南、北極海冰的長(zhǎng)期變化趨勢(shì)及其與大氣環(huán)流的聯(lián)系
    應(yīng)用MODIS數(shù)據(jù)監(jiān)測(cè)河北省近海海域海冰
    河北遙感(2014年4期)2014-07-10 13:54:59
    天堂av国产一区二区熟女人妻| 欧美日韩综合久久久久久| 真实男女啪啪啪动态图| 国产老妇伦熟女老妇高清| 成人漫画全彩无遮挡| 国产伦精品一区二区三区视频9| 永久网站在线| 精品一区二区三卡| 青春草国产在线视频| 精品久久久精品久久久| 久久99热这里只频精品6学生| 日韩欧美精品v在线| 日韩一本色道免费dvd| 成人一区二区视频在线观看| 男人爽女人下面视频在线观看| 亚洲一级一片aⅴ在线观看| 大陆偷拍与自拍| 亚洲美女搞黄在线观看| 亚洲欧美日韩卡通动漫| 中文字幕av成人在线电影| 成年女人在线观看亚洲视频 | 99久久精品热视频| 日韩在线高清观看一区二区三区| 国产中年淑女户外野战色| 乱人视频在线观看| 蜜臀久久99精品久久宅男| 日韩成人伦理影院| 少妇人妻精品综合一区二区| 久久久久久久久久黄片| 麻豆久久精品国产亚洲av| 国产欧美日韩精品一区二区| 免费看av在线观看网站| 少妇猛男粗大的猛烈进出视频 | 夫妻性生交免费视频一级片| 高清毛片免费看| 欧美成人a在线观看| 精品一区二区免费观看| 1000部很黄的大片| 国产精品人妻久久久久久| 干丝袜人妻中文字幕| 国产在视频线精品| 麻豆国产97在线/欧美| 亚洲欧美精品专区久久| 免费大片黄手机在线观看| 国产亚洲av片在线观看秒播厂 | 非洲黑人性xxxx精品又粗又长| 日本猛色少妇xxxxx猛交久久| av在线蜜桃| 国产免费又黄又爽又色| 成人性生交大片免费视频hd| 中国国产av一级| 搡女人真爽免费视频火全软件| 精品不卡国产一区二区三区| 国产精品麻豆人妻色哟哟久久 | 少妇的逼好多水| 欧美性感艳星| 最后的刺客免费高清国语| 插阴视频在线观看视频| 一本一本综合久久| 国产精品伦人一区二区| 日本一本二区三区精品| 精品久久久噜噜| 99久久人妻综合| 久热久热在线精品观看| 超碰97精品在线观看| 久久久久性生活片| 欧美xxxx性猛交bbbb| 日韩亚洲欧美综合| 最近手机中文字幕大全| 97热精品久久久久久| 日日摸夜夜添夜夜爱| 一级二级三级毛片免费看| 亚洲国产欧美人成| 亚洲av成人av| 亚洲熟妇中文字幕五十中出| 黑人高潮一二区| 亚洲精品色激情综合| 亚洲av男天堂| 免费电影在线观看免费观看| 菩萨蛮人人尽说江南好唐韦庄| 哪个播放器可以免费观看大片| 亚洲国产精品sss在线观看| 中文欧美无线码| 91aial.com中文字幕在线观看| 蜜臀久久99精品久久宅男| 国产精品国产三级专区第一集| 国产精品国产三级专区第一集| 日日啪夜夜撸| 国产三级在线视频| 久久99精品国语久久久| 亚洲精品,欧美精品| 亚洲熟女精品中文字幕| 免费看a级黄色片| 男女边摸边吃奶| 亚洲伊人久久精品综合| 一级片'在线观看视频| 国产精品女同一区二区软件| 精品欧美国产一区二区三| 中文字幕免费在线视频6| 欧美97在线视频| 日韩成人伦理影院| 色网站视频免费| 久久久午夜欧美精品| 日韩精品有码人妻一区| xxx大片免费视频| 精品久久国产蜜桃| 亚洲精品国产成人久久av| 卡戴珊不雅视频在线播放| 国产亚洲精品久久久com| 欧美 日韩 精品 国产| 国产精品麻豆人妻色哟哟久久 | 免费电影在线观看免费观看| 免费大片18禁| 国产在视频线精品| 亚洲一区高清亚洲精品| 亚洲精品乱码久久久v下载方式| 亚洲国产精品国产精品| 美女被艹到高潮喷水动态| www.av在线官网国产| 白带黄色成豆腐渣| 精品一区二区三区人妻视频| 国产不卡一卡二| 床上黄色一级片| 天天躁日日操中文字幕| 成人性生交大片免费视频hd| 亚洲久久久久久中文字幕| 日韩一区二区视频免费看| 亚洲,欧美,日韩| 国内精品美女久久久久久| 五月伊人婷婷丁香| 观看美女的网站| 99九九线精品视频在线观看视频| 99热网站在线观看| 热99在线观看视频| 搡女人真爽免费视频火全软件| 久久精品国产自在天天线| 日韩欧美精品v在线| 国产黄色免费在线视频| 久久精品人妻少妇| 天天躁夜夜躁狠狠久久av| 永久免费av网站大全| 国产免费福利视频在线观看| 精品熟女少妇av免费看| 天堂中文最新版在线下载 | 国产视频内射| 欧美丝袜亚洲另类| 国产麻豆成人av免费视频| 最近2019中文字幕mv第一页| 日韩 亚洲 欧美在线| 水蜜桃什么品种好| a级毛色黄片| 免费看日本二区| 久久久久久久大尺度免费视频| 精品99又大又爽又粗少妇毛片| 亚洲久久久久久中文字幕| 高清在线视频一区二区三区| 午夜久久久久精精品| 天堂网av新在线| 欧美潮喷喷水| 一级毛片aaaaaa免费看小| 免费人成在线观看视频色| 看黄色毛片网站| 免费av观看视频| 精品少妇黑人巨大在线播放| 国产毛片a区久久久久| 黄色日韩在线| 精品国产露脸久久av麻豆 | 亚洲国产av新网站| 99热网站在线观看| 亚洲内射少妇av| 国产精品女同一区二区软件| 欧美激情在线99| 美女内射精品一级片tv| 婷婷色综合www| 人妻少妇偷人精品九色| 国产人妻一区二区三区在| 欧美xxxx性猛交bbbb| 亚洲精品一区蜜桃| 欧美高清成人免费视频www| 人妻制服诱惑在线中文字幕| 国产成人精品福利久久| 精品国产露脸久久av麻豆 | 国产成人91sexporn| 国产一区亚洲一区在线观看| 精品久久久久久久久av| 视频中文字幕在线观看| 最后的刺客免费高清国语| 亚洲四区av| 午夜激情欧美在线| 晚上一个人看的免费电影| 久久精品国产鲁丝片午夜精品| 最近最新中文字幕大全电影3| 午夜免费观看性视频| 国产伦理片在线播放av一区| 伦理电影大哥的女人| 熟女电影av网| 日韩av在线免费看完整版不卡| av国产免费在线观看| 免费电影在线观看免费观看| 男女国产视频网站| 日本爱情动作片www.在线观看| av国产久精品久网站免费入址| 亚洲最大成人手机在线| 秋霞在线观看毛片| 亚洲一区高清亚洲精品| 日日啪夜夜爽| 赤兔流量卡办理| 久久久久免费精品人妻一区二区| 亚洲成色77777| 国产免费一级a男人的天堂| 国产 一区精品| 在线免费观看的www视频| 亚洲精品国产成人久久av| 免费观看无遮挡的男女| 日韩亚洲欧美综合| 成年免费大片在线观看| 日日啪夜夜爽| 亚洲人成网站在线观看播放| 亚洲欧美成人精品一区二区| 全区人妻精品视频| 七月丁香在线播放| 性色avwww在线观看| 超碰97精品在线观看| 亚洲,欧美,日韩| 婷婷色麻豆天堂久久| 色哟哟·www| 午夜激情欧美在线| 亚洲在线观看片| 大话2 男鬼变身卡| 如何舔出高潮| 成人一区二区视频在线观看| 少妇高潮的动态图| 又大又黄又爽视频免费| 午夜福利视频精品| 尤物成人国产欧美一区二区三区| 国产白丝娇喘喷水9色精品| 少妇丰满av| 国产成人a∨麻豆精品| 伊人久久国产一区二区| 国产毛片a区久久久久| 国产伦精品一区二区三区视频9| 欧美成人一区二区免费高清观看| 日日啪夜夜爽| 美女脱内裤让男人舔精品视频| 亚洲欧洲国产日韩| 免费观看无遮挡的男女| 中文字幕亚洲精品专区| 免费av观看视频| 一级毛片黄色毛片免费观看视频| 国产黄频视频在线观看| 99久久中文字幕三级久久日本| 一级二级三级毛片免费看| 99久久精品国产国产毛片| 女的被弄到高潮叫床怎么办| 成年女人在线观看亚洲视频 | 中国美白少妇内射xxxbb| 中文欧美无线码| 国产综合精华液| 久久精品国产鲁丝片午夜精品| 国产精品久久久久久久电影| 亚洲综合色惰| 久久久久精品性色| 尾随美女入室| 美女主播在线视频| 女人十人毛片免费观看3o分钟| 亚洲久久久久久中文字幕| 国产精品1区2区在线观看.| 亚洲av成人精品一二三区| 国产成人a∨麻豆精品| 欧美成人午夜免费资源| 亚洲国产日韩欧美精品在线观看| 日产精品乱码卡一卡2卡三| 听说在线观看完整版免费高清| 少妇人妻精品综合一区二区| 91狼人影院| 26uuu在线亚洲综合色| av在线播放精品| 直男gayav资源| 天天一区二区日本电影三级| 亚洲欧洲国产日韩| 最近手机中文字幕大全| 成人综合一区亚洲| 国产女主播在线喷水免费视频网站 | 亚洲内射少妇av| 久久久久精品性色| 国产精品不卡视频一区二区| 亚洲真实伦在线观看| 一级毛片电影观看| 国产精品一二三区在线看| 久久久精品免费免费高清| 汤姆久久久久久久影院中文字幕 | 国产美女午夜福利| 国产成人一区二区在线| 日韩中字成人| 亚洲欧美日韩卡通动漫| 久热久热在线精品观看| 久久亚洲国产成人精品v| 国产午夜精品久久久久久一区二区三区| 超碰av人人做人人爽久久| 女人被狂操c到高潮| 国产毛片a区久久久久| 国产爱豆传媒在线观看| 欧美性感艳星| 亚洲国产成人一精品久久久| 久久久久久久久久久免费av| 99热网站在线观看| 在线 av 中文字幕| 中文在线观看免费www的网站| 国产伦在线观看视频一区| 自拍偷自拍亚洲精品老妇| 综合色av麻豆| 久久久久精品性色| 青春草视频在线免费观看| 国产成人精品久久久久久| 亚洲av.av天堂| 国精品久久久久久国模美| 九九爱精品视频在线观看| 亚洲最大成人中文| 91av网一区二区| 美女内射精品一级片tv| 久热久热在线精品观看| 高清视频免费观看一区二区 | 春色校园在线视频观看| 99久久人妻综合| 国产有黄有色有爽视频| 久久久久久久久大av| 国模一区二区三区四区视频| 中文字幕人妻熟人妻熟丝袜美| av天堂中文字幕网| 少妇人妻一区二区三区视频| 午夜亚洲福利在线播放| 麻豆av噜噜一区二区三区| 亚洲国产日韩欧美精品在线观看| 日本与韩国留学比较| 欧美日韩视频高清一区二区三区二| 韩国av在线不卡| 国产在线男女| 亚洲熟女精品中文字幕| 亚洲av一区综合| 韩国高清视频一区二区三区| 日韩,欧美,国产一区二区三区| 国产精品无大码| 大香蕉97超碰在线| 亚洲在线观看片| av网站免费在线观看视频 | 久久久久九九精品影院| 一级爰片在线观看| 麻豆久久精品国产亚洲av| 亚洲av成人av| 非洲黑人性xxxx精品又粗又长| 国产在线男女| 免费高清在线观看视频在线观看| 亚洲精品久久午夜乱码| 免费看日本二区| 黄色配什么色好看| 精品一区二区免费观看| 性色avwww在线观看| 国产午夜精品一二区理论片| 日韩欧美 国产精品| 亚洲内射少妇av| 美女高潮的动态| 看黄色毛片网站| 日韩av不卡免费在线播放| 男女国产视频网站| 成年免费大片在线观看| 熟妇人妻久久中文字幕3abv| 少妇被粗大猛烈的视频| 卡戴珊不雅视频在线播放| 日本三级黄在线观看| 国产精品久久久久久久电影| 少妇的逼好多水| 少妇熟女欧美另类| 高清视频免费观看一区二区 | 欧美xxxx性猛交bbbb| 一个人看视频在线观看www免费| 日韩欧美精品v在线| av国产久精品久网站免费入址| 国产免费又黄又爽又色| 男的添女的下面高潮视频| 舔av片在线| 午夜福利成人在线免费观看| 白带黄色成豆腐渣| 亚洲国产欧美人成| 男人狂女人下面高潮的视频| 99久久九九国产精品国产免费| 亚洲av男天堂| 亚洲精品日本国产第一区| 少妇熟女aⅴ在线视频| 美女黄网站色视频| 国产精品久久久久久精品电影小说 | 高清视频免费观看一区二区 | 成人性生交大片免费视频hd| 中国美白少妇内射xxxbb| 亚洲成人中文字幕在线播放| 久久韩国三级中文字幕| 国产一区有黄有色的免费视频 | 日韩三级伦理在线观看| 最近2019中文字幕mv第一页| 伦精品一区二区三区| 少妇丰满av| 狂野欧美白嫩少妇大欣赏| 国产伦在线观看视频一区| 九九久久精品国产亚洲av麻豆| 一区二区三区免费毛片| 一级爰片在线观看| 日韩精品青青久久久久久| 国产黄色小视频在线观看| 欧美高清性xxxxhd video| 两个人的视频大全免费| 国产亚洲最大av| 欧美 日韩 精品 国产| 亚洲欧美精品自产自拍| a级毛片免费高清观看在线播放| 午夜精品国产一区二区电影 | 伊人久久国产一区二区| av在线蜜桃| 欧美性感艳星| 久久精品国产亚洲av天美| 亚洲激情五月婷婷啪啪| 69av精品久久久久久| 又黄又爽又刺激的免费视频.| 男女边摸边吃奶| 一夜夜www| 啦啦啦韩国在线观看视频| 免费高清在线观看视频在线观看| 91久久精品国产一区二区成人| 国产色婷婷99| 精品久久久久久久久亚洲| 久久久久精品性色| 欧美激情久久久久久爽电影| 日韩制服骚丝袜av| 国产人妻一区二区三区在| 黄色配什么色好看| 又粗又硬又长又爽又黄的视频| 国产一级毛片在线| 亚洲精品久久久久久婷婷小说| 卡戴珊不雅视频在线播放| 80岁老熟妇乱子伦牲交| 美女主播在线视频| 国产淫片久久久久久久久| 搞女人的毛片| 亚洲一级一片aⅴ在线观看| 麻豆乱淫一区二区| 欧美最新免费一区二区三区| 最近视频中文字幕2019在线8| av在线老鸭窝| 精品久久久久久久久亚洲| 国产精品嫩草影院av在线观看| 黄色配什么色好看| 有码 亚洲区| 亚洲天堂国产精品一区在线| 日韩精品青青久久久久久| 国产亚洲精品久久久com| 国产又色又爽无遮挡免| 亚洲欧洲国产日韩| 国产精品一区www在线观看| 欧美激情久久久久久爽电影| 亚洲欧洲日产国产| 色尼玛亚洲综合影院| 中文欧美无线码| 亚洲四区av| 欧美激情久久久久久爽电影| 久久人人爽人人爽人人片va| 亚洲精品国产av蜜桃| 午夜福利高清视频| av卡一久久| 十八禁网站网址无遮挡 | 夫妻午夜视频| 极品少妇高潮喷水抽搐| 777米奇影视久久| 欧美 日韩 精品 国产| 国产精品福利在线免费观看| 狂野欧美白嫩少妇大欣赏| 边亲边吃奶的免费视频| 国产精品熟女久久久久浪| 国产精品久久久久久久电影| 国产精品久久视频播放| 女人久久www免费人成看片| 最近中文字幕高清免费大全6| 日日摸夜夜添夜夜添av毛片| 丰满乱子伦码专区| 秋霞伦理黄片| 床上黄色一级片| 国产免费又黄又爽又色| 免费不卡的大黄色大毛片视频在线观看 | 又黄又爽又刺激的免费视频.| 日韩制服骚丝袜av| 亚洲久久久久久中文字幕| 欧美日韩精品成人综合77777| 成人二区视频| 亚洲欧美中文字幕日韩二区| 国产有黄有色有爽视频| 国产精品久久久久久av不卡| 岛国毛片在线播放| 两个人视频免费观看高清| 日韩,欧美,国产一区二区三区| 嫩草影院精品99| 亚洲三级黄色毛片| www.色视频.com| 成人亚洲精品av一区二区| 黄片wwwwww| 国产69精品久久久久777片| 亚洲av国产av综合av卡| 国产精品嫩草影院av在线观看| 欧美xxⅹ黑人| 18禁裸乳无遮挡免费网站照片| 老司机影院毛片| 性插视频无遮挡在线免费观看| 亚洲最大成人中文| 观看美女的网站| 国产成人午夜福利电影在线观看| 国产一区二区亚洲精品在线观看| 久久久久久久亚洲中文字幕| 美女国产视频在线观看| av线在线观看网站| 婷婷六月久久综合丁香| 亚洲人成网站在线播| 精华霜和精华液先用哪个| 一级av片app| 2021天堂中文幕一二区在线观| 国产精品久久久久久久久免| 免费播放大片免费观看视频在线观看| 国产91av在线免费观看| 搡女人真爽免费视频火全软件| 欧美极品一区二区三区四区| 久久久午夜欧美精品| 毛片女人毛片| 女人久久www免费人成看片| 综合色av麻豆| 十八禁国产超污无遮挡网站| 久久精品国产自在天天线| 51国产日韩欧美| 精品不卡国产一区二区三区| 日本免费a在线| 美女被艹到高潮喷水动态| 亚洲国产av新网站| 国产视频内射| 午夜福利网站1000一区二区三区| 欧美日韩国产mv在线观看视频 | 久久久国产一区二区| 亚洲精品乱码久久久v下载方式| 亚洲真实伦在线观看| 精品一区二区三区视频在线| av天堂中文字幕网| 视频中文字幕在线观看| 精品久久久久久久人妻蜜臀av| 美女黄网站色视频| 99热这里只有精品一区| 久久99蜜桃精品久久| 男人和女人高潮做爰伦理| 大陆偷拍与自拍| 69av精品久久久久久| 免费看不卡的av| 午夜激情久久久久久久| 久久精品国产鲁丝片午夜精品| 亚洲欧美日韩无卡精品| 精品人妻熟女av久视频| 永久网站在线| 精品久久久精品久久久| 免费大片黄手机在线观看| 欧美性感艳星| 久久这里有精品视频免费| 97超视频在线观看视频| 亚洲国产精品国产精品| 国产不卡一卡二| 婷婷色av中文字幕| 神马国产精品三级电影在线观看| 精品一区二区三区视频在线| 日本免费在线观看一区| 国产成人a∨麻豆精品| 免费看光身美女| 欧美性感艳星| 91精品一卡2卡3卡4卡| 国产亚洲午夜精品一区二区久久 | 韩国av在线不卡| 亚洲激情五月婷婷啪啪| 亚洲欧美一区二区三区国产| ponron亚洲| 成人性生交大片免费视频hd| 中文字幕av成人在线电影| 国产成人aa在线观看| 国产午夜福利久久久久久| 插阴视频在线观看视频| 精品国产一区二区三区久久久樱花 | 国产成人91sexporn| 高清毛片免费看| 国内揄拍国产精品人妻在线| 欧美丝袜亚洲另类| 国产精品综合久久久久久久免费| 亚洲四区av| 天堂中文最新版在线下载 | 精品久久久久久久久亚洲| 亚洲精品中文字幕在线视频 | 亚洲av中文字字幕乱码综合| 一边亲一边摸免费视频| 亚洲三级黄色毛片| 五月玫瑰六月丁香| 国产成人精品一,二区| 一级毛片 在线播放| 日韩欧美国产在线观看| 日日撸夜夜添| av黄色大香蕉| 七月丁香在线播放| 观看免费一级毛片| 丰满人妻一区二区三区视频av| 国产亚洲av片在线观看秒播厂 | 一夜夜www| 欧美激情久久久久久爽电影| 丝袜美腿在线中文| 亚洲成色77777| 欧美日韩国产mv在线观看视频 | 天美传媒精品一区二区| 波多野结衣巨乳人妻| 久久久久久国产a免费观看| 小蜜桃在线观看免费完整版高清|