Abnormal Warming of the Summer Surface Air Temperature in Central Asia from 1980 to 2019
-
摘要: 本文利用1980～2019年NCEP/NCAR全球再分析资料、CRU地表气温资料、积雪覆盖率资料和全球海温资料，分析了中亚夏季地表气温的气候突变及其和北大西洋海温、青藏高原积雪之间的关系。结果表明：中亚夏季地表气温在2005年发生明显的气候突变。标准化的中亚区域平均的气温指数从之前的负位相为主变为之后的正位相为主，表示中亚地区夏季地表气温显著增温。和中亚夏季地表气温异常增温相联系的大气环流场的分析表明，2005年之后，中亚地区西侧的反气旋性环流系统异常增强，该反气旋异常对应的大气下沉增暖以及反气旋异常增强引起的云量减少进而导致向下的短波辐射增加均有利于中亚夏季气温异常升高。进一步的合成分析表明，中亚夏季地表气温在2005年的气候突变和北大西洋中高纬度地区的海表温度的增暖和青藏高原西部积雪的减少有着密切关系。北大西洋中高纬度海表温度增温能激发一个向下游传播的罗斯贝波，青藏高原西部积雪减少能够通过积雪的反照率效应对上空的大气有增温作用，两者均能增强中亚地区上空的反气旋系统，从而有利于中亚夏季地表气温异常偏高。Abstract: This work analyzes the abrupt change in summer surface air temperature (SAT) in Central Asia (CA) and its relationship with sea surface temperature (SST) in the North Atlantic and snow cover in the Qinghai Tibet Plateau between 1980 and 2019 based on NCEP/NCAR reanalysis data, CRU SAT, and snow cover and global SST data. The results reveal a significant summer SAT change in CA in 2005. The standardized regional average temperature index in CA shifts from the previous negative phase to the subsequent positive phase, indicating a significant summer SAT increase in CA. Analysis of the anomalous atmospheric circulations related to interdecadal changes in summer SAT in CA shows the abnormally enhanced anticyclonic circulation system in the west of CA after 2005. The atmospheric subsidence associated with the anomalous anticyclone can cause warming. On the other hand, the reduction in the amount of cloud caused by this anticyclone anomaly enhancement results in the increase in downward short-wave radiation and thus is favorable for the increased summer temperature in CA. Furthermore, the interdecadal summer SAT changes in CA in 2005 are closely related to SST warming in the middle and high latitudes of the North Atlantic and the reduction in snow cover in the west of the Tibet Plateau (TP). The SST increase in the middle and high latitudes of the North Atlantic can stimulate a Rossby wave propagating downstream. The reduction in snow cover in the west of the TP can cause warming to the above atmosphere through the snow albedo effect. The changes in both the North Atlantic SST and the TP snow can strengthen the anticyclone over CA, leading to an abnormally high summer SAT over there.
-
Key words:
- Central Asia /
- Summer SAT (Surface Air Temperature) /
- Interdecadal changes /
- SST /
- Snow cover
-
图 1 1980～2019年中亚以及周边地区夏季（a）地表气温（填色，单位：°C）叠加850 hPa风场（矢量，单位：m s−1）以及（b）200 hPa纬向风（填色，单位：m s−1）叠加风场（矢量，单位：m s−1）的气候平均分布；（c）1950～2019年中亚地区[（a）中红色框区域；（36°～55°N，40°～90°E）]区域平均的地表气温距平直方图
Figure 1. Climatological summer (a) SAT (Surface Air Temperature, shading, units: °C) and 850-hPa wind (vectors, units: m s−1), (b) 200-hPa zonal wind (shading, units: m s−1) and wind (vectors, units: m s−1) in CA (Central Asia) and the surrounding areas from 1980 to 2019. (c) Regional average surface air temperature anomaly in CA [red box area in (a), (36°−55°N, 45°−90°E)] from 1950 to 2019
图 2 1980～2019年中亚地区（36°～55°N，40°～90°E）夏季地表气温场EOF分析（a）第一模态（EOF1）的空间分布型（单位：°C）和（b）EOF1对应的标准化时间序列（直方图）及其11年的低频滤波（黑色实曲线），图（a）中打点区域表示通过95%的显著性检验，右上角百分数为EOF1的方差解释率。（c）标准化的中亚地区区域平均的地表气温指数（直方图）及其11年的低频滤波（黑色实曲线），虚线表示地表气温指数的正负0.5标准方差
Figure 2. (a) Spatial pattern of the first EOF (EOF1) of summer (June−July−August) SAT (units: °C; shading) over CA (36°−55°N, 45°−90°E) represented by regressing SAT onto the time series of EOF1 from 1979 to 2019. The number on the top right corner indicates the percentage of the variance explained by EOF1. Anomalies significant at the 95% confidence level are dotted. The yellow box in (a) represents CA. (b) Corresponding time series of EOF1 (PC1) (bar charts). The black line represents the low-frequency component of PC1 with periods longer than 10 years. (c) Area-weighted averaged summer temperature index (TI) over CA (represented by the solid bar charts) and low-frequency components of TI (represented by the black solid line). The horizontal long dashed black lines denote the ±0.5 standard deviation
图 3 1980～2019年（a）中亚夏季地表气温场EOF1对应的标准化的时间序列和（b）中亚地区区域平均的地表气温指数的MK（Mann–Kendall）检验。黑色实线为前向曲线（UF），蓝色实线为后向曲线（UB）。水平虚线为95%显著性线，垂直虚线标示UF和UB的交点。
Figure 3. Mann–Kendall (MK) statistic curves of (a) the PC1 of the EOF1 of summer SAT over CA and (b) the area-weighted averaged summer TI over CA. The solid blue and solid black lines are the forward (UF) and backward (UB) curves, respectively. The horizontal long dashed black lines denote the 95% confidence level, and the dashed vertical line denotes the intersection of the UF and UB
图 4 中亚夏季暖年和冷年的（a）地表气温（填色，单位：°C）与850 hPa风场（箭头，单位：m s−1）、（b）500 hPa垂直速度场（单位：Pa s−1）、（c）200 hPa风场（矢量，单位：m s−1）叠加风速场（填色，单位：m s−1）和（d）总云量覆盖率的合成差值场。图中打点区域表示通过95%的显著性检验
Figure 4. Composite differences of the (a) SAT temperature (shading, units: °C) and 850-hPa wind (vectors, units: m s−1), (b) 500-hPa vertical velocity (shading, units: Pa s−1), (c) 200h-Pa wind (vectors, units: m s−1) and wind speed (shading, units: m s−1), and (d) total cloud cover (shading) between the warm and cold years in CA. Anomalies significant at the 95% confidence level are dotted
图 5 中亚夏季暖年和冷年的地表下行短波辐射通量（填色，单位：W m−2）的合成差值场。图中打点区域表示通过95%的显著性检验
Figure 5. Composite difference of downward solar radiation flux at the surface (shading, units: W m−2) between the warm and cold years in CA. Anomalies significant at the 95% confidence level are dotted
图 6 中亚夏季暖年和冷年的（a）大西洋海温（填色；单位：°C）的合成差值场。（b）标准化的北大西洋中高纬度（35°～80°N，70°W～10°E）区域平均海温指数（直方图）及其11年的低频滤波（黑色曲线）。北大西洋中高纬度区域平均海温指数对（c）夏季地表气温（填色，单位：°C）和850 hPa风场（矢量，单位：m s−1）以及（d）200 hPa风场（矢量，单位：m s−1）和风速场（填色，单位：m/s）的异常回归场。图中打点区域均表示通过95%的显著性检验
Figure 6. (a) Composite differences of the summer SST (shading, units: °C) between the warm and cold years in CA. (b) Normalized SST index obtained by the area-weighted average of SST over the key region of the North Atlantic (35°–80°N, 70°W–10°E; represented by the solid bar charts) and low-frequency components of the index (represented by the black dotted line). Anomalies in the summer (c) SAT (shading, units: °C) and 850-hPa wind (vectors, units: m s−1) and (d) 200-hPa wind (vectors, units: m s−1) and wind speed (shading, units: m s−1) obtained by regression against the sea surface TI from 1980 to 2019. Anomalies significant at the 95% confidence level are dotted
图 7 中亚夏季暖年和冷年的（a）青藏高原积雪覆盖率的合成差值场。（b）标准化的青藏高原西部（32°～44°N，70°～80°E）区域平均积雪指数（直方图）及其11年的低频滤波（黑色曲线）。（c）青藏高原西部积雪指数对地表气温（填色，单位：°C）与850 hPa风场（箭头，单位：m s−1）的回归图。（d）青藏高原西部积雪指数对200 hPa风场（矢量，单位：m s−1）与风速（填色，单位：m s−1）的回归图。图中的打点区域表示通过95%的显著性检验
Figure 7. (a) Composite differences of the snow cover extent (SCE, shading) between the warm and cold years in CA. (b) Normalized snow index obtained by the area-weighted average of the SCE over the key region of the western TP (32°–44°N, 70°–80°E; represented by the solid bar charts) and low-frequency components of the index (represented by the black dotted line). Anomalies in the summer (c) SAT (shading, units: °C) and 850-hPa wind (vectors, units: m s−1), (d) 200-hPa wind (vectors, units: m s−1), and wind speed (shading, units: m s−1) obtained by regression against the snow index from 1980 to 2019. Anomalies significant at the 95% confidence level are dotted
图 8 青藏高原西部积雪指数对（a）地表气温（填色；单位：°C）与850 hPa风场（箭头，单位：m s−1），（b）200 hPa风场（矢量，单位：m s−1）和风速场（填色，单位：m s−1）去掉北大西洋海温指数的偏回归图。打点区域表示通过95%的显著性检验
Figure 8. Anomalies in the summer (c) SAT (shading, units: °C) and 850-hPa wind (vectors, units: m s−1) and (b) 200-hPa wind (vectors, units: m s−1) and wind speed (shading, units: m s−1) obtained by partial regression against the snow index after removing the North Atlantic sea surface TI from 1980 to 2019. Anomalies significant at the 95% confidence level are dotted
-
[1] Blanford H F. 1884. II. On the connexion of the himalaya snowfall with dry winds and seasons of drought in India [J]. Proceedings of the Royal Society of London, 37(232–234): 3–22. doi:10.1098/rspl.1884.0003 [2] Brohan P, Kennedy J J, Harris I, et al. 2006. Uncertainty estimates in regional and global observed temperature changes: A new data set from 1850 [J]. J. Geophys. Res., 111(D12): D12106. doi: 10.1029/2005JD006548 [3] Brodzik M, Armstrong R. 2013. Northern Hemisphere EASE-Grid 2.0 weekly snow cover and sea ice extent, version 4[J]. National Snow and Ice Data Center, Boulder, CO, digital media. [Available online athttps: //nsidc.org/data/docs/daac/nsidc0046_nh_ease_snow_seaice. gd. html.]. [4] Chen F H, Chen J H, Huang W, et al. 2019. Westerlies Asia and monsoonal Asia: Spatiotemporal differences in climate change and possible mechanisms on decadal to sub-orbital timescales [J]. Earth-Sci. Rev., 192: 337−354. doi: 10.1016/j.earscirev.2019.03.005 [5] Chen Y N, Deng H J, Li B F, et al. 2014. Abrupt change of temperature and precipitation extremes in the arid region of Northwest China [J]. Quat. Int., 336: 35−43. doi: 10.1016/j.quaint.2013.12.057 [6] Duan A M, Wu G X. 2005. Role of the Tibetan Plateau thermal forcing in the summer climate patterns over subtropical Asia [J]. Climate Dyn. , 24(7–8): 793–807. doi:10.1007/s00382-004-0488-8 [7] 段安民, 肖志祥, 吴国雄. 2016. 1979–2014年全球变暖背景下青藏高原气候变化特征 [J]. 气候变化研究进展, 12(5): 374−381. doi: 10.12006/j.issn.1673-1719.2016.039Duan Anmin, Xiao Zhixiang, Wu Guoxiong. 2016. Characteristics of climate change over the Tibetan Plateau under the global warming during 1979–2014 [J]. Climate Change Research (in Chinese), 12(5): 374−381. doi: 10.12006/j.issn.1673-1719.2016.039 [8] 段安民, 肖志祥, 吴国雄, 等. 2014. 青藏高原冬春积雪影响亚洲夏季风的研究进展 [J]. 气象与环境科学, 37(3): 94−101. doi: 10.3969/j.issn.1673-7148.2014.03.015Duan Anmin, Xiao Zhixiang, Wu Guoxiong, et al. 2014. Study progress of the influence of the Tibetan Plateau winter and spring snow depth on Asian summer monsoon [J]. Meteorological and Environmental Sciences (in Chinese), 37(3): 94−101. doi: 10.3969/j.issn.1673-7148.2014.03.015 [9] Estilow T W, Young A H, Robinson D A. 2015. A long-term Northern Hemisphere snow cover extent data record for climate studies and monitoring [J]. Earth System Science Data, 7(1): 137−142. doi: 10.5194/essd-7-137-2015 [10] Fujinami H, Yasunari T. 2009. The effects of midlatitude waves over and around the Tibetan Plateau on submonthly variability of the East Asian summer monsoon [J]. Mon. Wea. Rev., 137(7): 2286−2304. doi: 10.1175/2009MWR2826.1 [11] Harris I, Jones P D, Osborn T J, et al. 2014. Updated high-resolution grids of monthly climatic observations—The CRU TS3.10 dataset [J]. Int. J. Climatol., 34(3): 623−642. doi: 10.1002/joc.3711 [12] Hu Z Y, Zhang C, Hu Q, et al. 2014. Temperature changes in central Asia from 1979 to 2011 based on multiple datasets [J]. J. Climate, 27(3): 1143−1167. doi: 10.1175/JCLI-D-13-00064.1 [13] Huang B Y, Thorne P W, Banzon V F, et al. 2017. Extended reconstructed sea surface temperature, version 5 (ERSSTv5): Upgrades, validations, and intercomparisons [J]. J. Climate, 30(20): 8179−8205. doi: 10.1175/JCLI-D-16-0836.1 [14] Jia X J, Zhang C, Wu R G, et al. 2021. Influence of Tibetan Plateau autumn snow cover on interannual variations in spring precipitation over southern China [J]. Climate Dyn., 56(3–4): 767–782. doi:10.1007/s00382-020-05497-8 [15] Kanamitsu M, Ebisuzaki W, Woollen J, et al. 2002. NCEP-DOE AMIP-II reanalysis (R-2) [J]. Bull. Am. Meteor. Soc., 83(11): 1631−1644. doi: 10.1175/bams-83-11-1631 [16] Kendall M G. 1975. Rank Correlation Methods [M]. 4th ed. London: Charles Griffin and Co. , Ltd. [17] Li B F, Chen Y N, Shi X. 2012. Why does the temperature rise faster in the arid region of Northwest China? [J]. J. Geophys. Res., 117(D16): D16115. doi: 10.1029/2012JD017953 [18] Li B F, Li Y P, Chen Y N, et al. 2020. Recent fall Eurasian cooling linked to North Pacific sea surface temperatures and a strengthening Siberian high [J]. Nat. Commun., 11(1): 5202. doi: 10.1038/s41467-020-19014-2 [19] Li Z, Chen Y N, Li W H, et al. 2015. Potential impacts of climate change on vegetation dynamics in central Asia [J]. J. Geophys. Res., 120(24): 12345−12356. doi: 10.1002/2015JD023618 [20] 刘新, 李伟平, 吴国雄. 2002. 夏季青藏高原加热和北半球环流年际变化的相关分析 [J]. 气象学报, 60(3): 266−277. doi: 10.3321/j.issn:0577-6619.2002.03.002Liu Xin, Li Weiping, Wu Guoxiong. 2002. Interannual variation of the diabatic heating over the Tibetan Plateau and the Northern Hemispheric circulation in summer [J]. Acta Meteorologica Sinica (in Chinese), 60(3): 266−277. doi: 10.3321/j.issn:0577-6619.2002.03.002 [21] Liu X K, Jia X J, Wang M, et al. 2022. The impact of Tibetan Plateau snow cover on the summer temperature in central Asia [J]. Adv. Atmos. Sci., 39(7): 1103−1114. doi: 10.1007/s00376-021-1011-4 [22] Morinaga Y, Tian S F, Shinoda M. 2003. Winter snow anomaly and atmospheric circulation in Mongolia [J]. Int. J. Climatol., 23(13): 1627−1636. doi: 10.1002/joc.961 [23] North G R, Bell T L, Cahalan R F, et al. 1982. Sampling errors in the estimation of empirical orthogonal functions [J]. Mon. Wea. Rev., 110(7): 699−706. doi: 10.1175/1520-0493(1982)110<0699:seiteo>2.0.co;2 [24] Qian Q F, Jia X J, Wu R G. 2020. On the interdecadal change in the interannual variation in autumn snow cover over the central eastern Tibetan Plateau in the Mid-1990s [J]. J. Geophys. Res., 125(16): e2020JD032685. doi: 10.1029/2020JD032685 [25] Robinson D A, Dewey K F, Heim R R. 1993. Global snow cover monitoring: An update [J]. Bull. Am. Meteor. Soc., 74(9): 1689−1696. doi: 10.1175/1520-0477(1993)074<1689:GSCMAU>2.0.CO;2 [26] Robinson D A. 2012. NOAA climate data record (CDR) of northern Hemisphere (NH) snow cover extent (SCE), version 1 [EB/OL]. https://www.ncei.noaa.gov/access/metadata/landing-page/bin/iso?id=gov.noaa.ncdc:C00756 [27] Schiemann R, Lüthi D, Vidale P L, et al. 2008. The precipitation climate of central Asia-Intercomparison of observational and numerical data sources in a remote semiarid region [J]. Int. J. Climatol., 28(3): 295−314. doi: 10.1002/joc.1532 [28] Siegfried T, Bernauer T, Guiennet R, et al. 2012. Will climate change exacerbate water stress in Central Asia? [J]. Climate Change, 112(3–4): 881–899. doi:10.1007/s10584-011-0253-z [29] Smith T M, Reynolds R W. 2005. A global merged land–air–sea surface temperature reconstruction based on historical observations (1880–1997) [J]. J. Climate, 18(12): 2021−2036. doi: 10.1175/JCLI3362.1 [30] Sorg A, Bolch T, Stoffel M, et al. 2012. Climate change impacts on glaciers and runoff in Tien Shan (Central Asia) [J]. Nat. Climate Change, 2(10): 725−731. doi: 10.1038/nclimate1592 [31] Wang Z B, Wu R G, Huang G. 2018b. Low-frequency snow changes over the Tibetan Plateau [J]. Int. J. Climatol., 38(2): 949−963. doi: 10.1002/joc.5221 [32] Wang Z B, Wu R G, Chen S F, et al. 2018a. Influence of western Tibetan Plateau summer snow cover on East Asian summer rainfall [J]. J. Geophys. Res., 123(5): 2371−2386. doi: 10.1002/2017JD028016 [33] Watanabe M. 2004. Asian jet waveguide and a downstream extension of the North Atlantic Oscillation [J]. J. Climate, 17(24): 4674−4691. doi: 10.1175/JCLI-3228.1 [34] 韦志刚, 黄荣辉, 陈文, 等. 2002. 青藏高原地面站积雪的空间分布和年代际变化特征 [J]. 大气科学, 26(4): 496−508. doi: 10.3878/j.issn.1006-9895.2002.04.07Wei Zhigang, Huang Ronghui, Chen Wen, et al. 2002. Spatial distributions and interdecadal variations of the snow at the Tibetan Plateau weather stations [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 26(4): 496−508. doi: 10.3878/j.issn.1006-9895.2002.04.07 [35] Wu B Y, Wang J. 2002. Possible impacts of winter arctic oscillation on siberian high, the East Asian winter monsoon and sea–ice extent [J]. Adv. Atmos. Sci. 19(2): 297–320. doi:10.1007/s00376-002-0024-x [36] Yao J Q, Chen Y N. 2015. Trend analysis of temperature and precipitation in the Syr Darya Basin in central Asia [J]. Theor. Appl. Climatol. , 120(3–4): 521–531. doi:10.1007/s00704-014-1187-y [37] Yasunari T, Kitoh A, Tokioka T. 1991. Local and remote responses to excessive snow mass over eurasia appearing in the northern spring and summer climate: A study with the MRI·GCM [J]. J. Meteor. Soc. Japan, 69(4): 473−487. doi: 10.2151/jmsj1965.69.4_473 [38] 叶笃正, 高由禧, 周明煜, 等. 1979. 青藏高原气象学 [M]. 北京: 科学出版社.Ye Duzheng, Gao Youxi, Zhou Mingyu, et al. 1979. Qinghai–Xizang Plateau Meteorology (in Chinese) [M]. Beijing: Science Press. [39] You Y J, Jia X J. 2018. Interannual variations and prediction of spring precipitation over China [J]. J. Climate, 31(2): 655−670. doi: 10.1175/JCLI-D-17-0233.1 [40] Zhang C, Jia X J, Wen Z P. 2021. Increased impact of the Tibetan Plateau spring snow cover to the Mei-yu rainfall over the Yangtze River valley after the 1990s [J]. J. Climate, 34(14): 5985−5997. doi: 10.1175/JCLI-D-21-0009.1 [41] Zhao P, Chen L X. 2001. Climatic features of atmospheric heat source/sink over the Qinghai–Xizang Plateau in 35 years and its relation to rainfall in China [J]. Sci. China Ser. D:Earth Sci., 44(9): 858−864. doi: 10.1007/BF02907098 -
下载:
点击查看大图
计量
- 文章访问数: 209
- HTML全文浏览量: 50
- PDF下载量: 39
- 被引次数: 0
