﻿ 基于CCSM4.0长期积分试验评估不同辐射强迫对中国干旱半干旱区降水的影响 基于CCSM4.0长期积分试验评估不同辐射强迫对中国干旱半干旱区降水的影响
 大气科学  2018, Vol. 42 Issue (2): 311-322 PDF

1 中国科学院大气物理研究所中国科学院东亚区域气候-环境重点实验室, 北京 100029
2 天津市气象台, 天津 300074
3 兰州大学大气科学院, 兰州 730000

Effects of Radiative Forcing on Precipitation over Arid and Semi-arid Region in China Based on CCSM4.0 Simulation
ZHAO Tianbao1, CONG Jing2,3
1 Key Laboratory of Regional Climate-Environment Research for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029
2 Tianjin Municipal Meteorological Observatory, Tianjin 300074
3 College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000
Key words: Effects of radiative forcing      CCSM 4.0 model      Precipitation      Arid and semi-arid region
1 引言

2 试验设计及验证 2.1 模式与试验设计

2.2 模拟结果验证

 图 1 多年平均降水空间分布图及其季节变化（单位: mm d-1）：（a）1970~2005年GPCC观测降水量；（b）B1850模拟降水量；（c）B2000模拟降水量；（d）区域平均降水季节变化。R表示图(a)与（b）以及图（a）与（c）空间模态相关系数 Figure 1 Spatial patterns and seasonal variability of observed and simulated multi-year average precipitation (units: mm d-1): (a) GPCC precipitation during 1970–2005; (b) simulated precipitation for B1850; (c) simulated precipitation for B2000; (d) seasonal variation of simulated and observed precipitation averaged over whole China. The spatial correlation coefficient between (a) and (b) and that between (a) and (c) are denoted by R in the panels
3 结果分析 3.1 时空分布特征与差异

 图 2 现时辐射强迫降水（B2000）与工业革命前辐射强迫结果（B1850）的差异（单位: mm d-1）：（a）年平均；（b）冬季（DJF）；（c）夏季（JJA） Figure 2 Differences in long-term mean precipitation (units: mm d-1) between simulations with present-day (B2000) and preindustrial (B1850) radiative forcing: (a) Annual mean; (b) winter (DJF); (c) summer (JJA)

 图 3 现时辐射强迫（B2000, 左列）与工业革命前辐射强迫（B1850，右列）降水的长期趋势[单位: 10-2 mm d-1 (100a)-1]：（a，b）年平均；（c，d）冬季；（e，f）夏季。图中所示阴影区域通过0.05显著性检验 Figure 3 Spatial patterns of long linear trends of precipitation change [units: 10-2 mm d-1 (100a) -1] simulated by CCSM 4.0 model under present-day (B2000, left column) and pre-industrial (B1850, right column) radiative forcing: (a, b) Winter; (c, d) summer; (e, f) annual mean. The stippling indicates statistical significance at 0.05 level

 图 4 区域平均降水量差异及其距平时间序列：（a）现时辐射强迫降水（B2000）与工业革命前辐射强迫结果（B1850）的差异（单位：mm d-1）；（b）现时辐射强迫降水量距平（B2000）与工业革命前辐射强迫结果（B1850）的时间序列（单位：mm d-1）。图中所示阴影区域以及时间序列均为两次31年滑动平均结果，图（b）中的R为二者的相关系数，P1850与P2000为二者的长期趋势 Figure 4 (a) Regionally averaged difference in annual precipitation rate (units: mm d-1) between the B2000 and B1850 simulations, and (b) regionally averaged time series of annual precipitation anomalies (units: mm d-1) derived from two simulations. The long-term trends derived from the two time series (P1850 and P2000) and the correlation coefficient of the simulated precipitation (R) between the B1850 and B2000 are also shown in (b)
3.2 频谱特征与差异

 图 5 不同辐射强迫下整个区域所有格点降水的距平时间序列的概率密度分布函数（PDFs） Figure 5 Probability density distribution function of time series of precipitation anomalies at all grid points within the study region in the present-day (B2000) and pre-industrial (B1850) simulations of CCSM4.0 model

 图 6 两种辐射强迫下区域年平均标准化降水时间序列小波功率谱（左列）及波谱（右列） Figure 6 Wavelet power spectra (left) and wavelet spectra (right) derived from annual precipitation anomalies averaged over the arid and semi-arid region in China based on B1850 and B2000 simulations, respectively. Annual precipitation is normalized by local standard deviation

3.3 EOF分析

 图 7 两种不同辐射强迫降水的EOF模态及其时间系数（PC）序列：（a，c）工业革命前辐射强迫（B1850）降水（a）EOF1与（c）EOF2模态；（b，d）当前辐射强迫（B2000）降水（b）EOF1与（d）EOF2模态；（e，f）分别经过两次31年平滑的（e）PC1和（f）PC2。各模态的解释方差在图中以百分数表示，PC1和PC2中两时间序列的相关系数以R表示；EOF分解是基于年平均标准化降水距平 Figure 7 The first two leading EOF modes and the corresponding twice 31-point-moving averaged PC time series derived from the CESM 4.0 simulations: (a, c) the (a) first and (c) second EOF modes for the B1850; (b, d) display the (b) first and (d) second EOF modes for the B2000; (e, f) the (e) first and (f) second PC time series. The annual precipitation anomalies were normalized by local standard deviation and multiplied by the square root of cosine of the latitude at each grid box before the EOF analysis. The percentage shows explained variance in Figs. 7a-d, and the PC correlation coefficients (R) between the two simulations are shown in Figs. 7e-f

3.4 不同辐射强迫下降水与热带海温异常的关系

 图 8 两种辐射强迫下年降水EOF分解时间系数（PC）与热带海温（SST）年平均距平相关性：（a，c）B1850试验中降水EOF前两模态的（a）PC1和（c）PC2（图 7e, f中的蓝线）与SST的相关系数空间分布；（b，d）同（a，c），但为B2000模拟试验。图中斜线阴影区表示通过了0.05的显著性检验 Figure 8 Spatial patterns of correlations between the PC time series corresponding to the first two EOF leading modes of annual precipitation anomalies and annual anomalies of the tropical sea surface temperature (SST) in the CESM 4.0 simulations forced by the preindustrial (B1850) and present-day (B2000) radiations, respectively. (a) and (c) are the correlation coefficients of the (a) PC1 and (c) PC2 (blue lines in Figs. 7e, f) with the SST, respectively, based on the B1850 simulation; (b) and (d) are same as (a) and (c) but for the B2000 simulation. The stippling indicates that the value is statistically significant at the 5% level

4 结果与讨论

（1）CCSM4.0能够模拟出全球陆地以及我国北方干旱半干旱区降水气候态的空间分布特征以及季节变化特征，但模拟的降水偏多，特别是在暖季比较明显。而这种系统性偏差除了模式本身的性能以及地形影响外，也与试验设计有关。因为本文所用的模拟试验结果仅是“平衡态”的气候敏感性试验，而非对真实历史气候变化的模拟。

（2）两种辐射强迫下我国干旱半干旱区降水的长期变化均无明显趋势，但二者的差异却呈现出70~100年的准周期振荡，这可能与太阳活动的格莱斯堡周期有关；而且由人类活动引起的现实辐射强迫降水（B2000）在最后约200年的时段具有更大的变率。

（3）从频谱分布来看，由人类活动引起的现实辐射强迫作用（B2000）会使我国干旱半干旱区极端强降水事件出现的概率增多；而由太阳活动引起的辐射强迫作用（B1850）主要对降水多年代际周期（30年左右）具有一定的调制作用。

（4）从EOF分解的结果来看，两种辐射强迫下我国干旱半干旱区降水变率的主要模态基本一致，进一步分析表明人类活动引起的辐射强迫作用对降水的年代际、多年代际变率及其长期趋势没有明显的影响，而自然因素外强迫（太阳活动）对降水的多年代际周期振荡有一定影响。

（5）研究结果还表明，中国北方干旱半干旱区降水变化与热带海温异常显著相关，人类活动引起的辐射强迫会影响降水多年代际变率与海温异常相互作用的强度，从而调节中国北方干旱半干旱区降水多年代际变率的幅度。

 Blackmon M, Boville B, Bryan F, et al. 2001. The community climate system model [J]. Bull. Amer. Meteor. Soc., 82(11): 2357-2376. DOI:10.1175/1520-0477(2001)082<2357:TCCSM>2.3.CO;2 Breitenmoser P, Beer J, Brönnimann S, et al. 2012. Solar and volcanic fingerprints in tree-ring chronologies over the past 2000 years [J]. Palaeogeogr. Palaeoclimatol. Palaeoecol., 313-314: 127-139. DOI:10.1016/j.palaeo.2011.10.014 Dai A G, Trenberth K, Qian T T. 2004. A global dataset of palmer drought severity index for 1870-2002:Relationship with soil moisture and effects of surface warming [J]. J. Hydrometeorol., 5(6): 1117-1130. DOI:10.1175/JHM-386.1 Dai A G. 2011a. Drought under global warming:A review [J]. Wiley Interdiscip. Rev. Climate Change, 2(1): 45-65. DOI:10.1002/wcc.81 Dai A G. 2011b. Characteristics and trends in various forms of the Palmer drought severity index during 1900-2008 [J]. J. Geophys. Res., 116(D12): D12115. DOI:10.1029/2010JD015541 Dai A G. 2013. Increasing drought under global warming in observations and models [J]. Nat. Climate Change, 3(1): 52-58. DOI:10.1038/nclimate1633 Feng S, Fu Q. 2013. Expansion of global drylands under a warming climate [J]. Atmos. Chem. Phys., 13(6): 14637-14665. DOI:10.5194/acpd-13-14637-2013 符淙斌, 温刚. 2002. 中国北方干旱化的几个问题[J]. 气候与环境研究, 7(1): 22-29. Fu Congbin, Wen Gang. 2002. Several issues on aridification in the northern China (in Chinese)[J]. Climatic and Environmental Research, 7(1): 22-29. DOI:10.3969/j.issn.1006-9585.2002.01.003 符淙斌, 马柱国. 2008. 全球变化与区域干旱化[J]. 大气科学, 32(4): 752-760. Fu Congbin, Ma Zhuguo. 2008. Global change and regional aridification (in Chinese)[J]. Chinese J. Atmos. Sci., 32(4): 752-760. DOI:10.3878/j.issn.1006-9895.2008.04.05 Gent P R, Danabasoglu G, Donner L J, et al. 2011. The community climate system model version 4 [J]. J. Climate, 24(19): 4973-4991. DOI:10.1175/2011JCLI4083.1 Huang J P, Guan X D, Ji F. 2012. Enhanced cold-season warming in semi-arid regions [J]. Atmos. Chem. Phys., 12(12): 5391-398. DOI:10.5194/acp-12-5391-2012 Huang J P, Yu H P, Guan X D, et al. 2016. Accelerated dryland expansion under climate change [J]. Nature Climate Change, 6(2): 166-171. DOI:10.1038/nclimate2837 IPCC. 2007. Climate Change 2007:The Physical Science Basis [M]. Cambridge, UK and New York, USA: Cambridge University Press. IPCC. 2013. Climate Change 2013:The Physical Science Basis [M]. Cambridge, UK and New York, USA: Cambridge University Press. Ji F, Wu Z H, Huang J P, et al. 2014. Evolution of land surface air temperature trend [J]. Nature Climate Change, 4(6): 462-466. DOI:10.1038/nclimate2223 李春香, 赵天保, 马柱国. 2014. 基于CMIP5多模式结果评估人类活动对全球典型干旱半干旱区气候变化的影响[J]. 科学通报, 59(30): 2972-2988. Li Chunxiang, Zhao Tianbao, Ma Zhuguo. 2014. Impacts of anthropogenic activities on climate change in arid and semiarid areas based on CMIP5 models (in Chinese)[J]. Chinese Science Bulletin, 59(30): 2972-2988. DOI:10.1360/N972014-00039 Li C X, Zhao T B, Ying K R. 2017. Quantifying the contributions of anthropogenic and natural forcings to climate changes overland during 1946-2005 [J]. Climatic Change. Liu J, Wang B, Ding Q H, et al. 2009. Centennial variations of the global monsoon precipitation in the last millennium:Results from ECHO-G model [J]. J. Climate, 22(9): 2356-2371. DOI:10.1175/2008JCLI2353.1 Liu J, Wang B, Wang H L, et al. 2011. Forced response of the East Asian summer rainfall over the past millennium:Results from a coupled model simulation [J]. Climate Dyn., 36(1-2): 323-336. DOI:10.1007/s00382-009-0693-6 马柱国. 2005. 我国北方干湿演变规律及其与区域增暖的可能联系[J]. 地球物理学报, 48(5): 1011-1018. Ma Zhuguo. 2005. Dry/wet variation and its relationship with regional warming in arid-regions of northern China (in Chinese)[J]. Chinese J. Geophys., 48(5): 1011-1018. DOI:10.3321/j.issn:0001-5733.2005.05.006 马柱国, 符淙斌. 2005. 中国干旱和半干旱带的10年际演变特征[J]. 地球物理学报, 48(3): 519-525. Ma Zhuguo, Fu Congbin. 2005. Decadal variations of arid and semi-arid boundary in China (in Chinese)[J]. Chinese J. Geophys., 48(3): 519-525. DOI:10.3321/j.issn:0001-5733.2005.03.008 Narisma G T, Foley J A, Licker R, et al. 2007. Abrupt changes in rainfall during the twentieth century [J]. Geophys. Res. Lett., 34(6): L06710. DOI:10.1029/2006GL028628 Nicholson S E, Tucker C J, Ba M B. 1998. Desertification, drought, and surface vegetation:An example from the West African Sahel [J]. Bull. Amer. Meteor. Soc., 79(5): 815-829. DOI:10.1175/1520-0477(1998)079<0815:DDASVA>2.0.CO;2 Quan X W, Hoerling M P, Perlwitz J, et al. 2014. How fast are the tropics expanding? [J]. J. Climate, 27(5): 1999-2013. DOI:10.1175/JCLI-D-13-00287.1 Schneider U, Becker A, Finger P, et al. 2014. GPCC's new land surface precipitation climatology based on quality-controlled in situ data and its role in quantifying the global water cycle [J]. Theor. Appl. Climatol., 115(1-2): 15-40. DOI:10.1007/s00704-013-0860-x Sun G W, Ye Q. 1996. A study on the variation of drought periods occurring in Northwest China and other Africa-Asia continental regions [J]. Acta Meteorologica Sinica, 10(4): 473-484. Taylor K E, Stouffer R J, Meehl G A. 2012. An overview of CMIP5 and the experiment design [J]. Bull. Amer. Meteor. Soc., 93(4): 485-498. DOI:10.1175/BAMS-D-11-00094.1 田芝平, 姜大膀. 2013. 不同分辨率CCSM4对东亚和中国气候模拟能力分析[J]. 大气科学, 37(1): 171-186. Tian Zhiping, Jiang Dapang. 2013. Evaluation of the performance of low-to high-resolution CCSM4 over East Asia and China (in Chinese)[J]. Chinese J. Atmos. Sci., 37(1): 171-186. DOI:10.3878/j.issn.1006-9895.2012.12050 田芝平, 姜大膀, 张冉, 等. 2012. CCSM4.0的长期积分试验及其对东亚和中国气候模拟的评估[J]. 大气科学, 36(3): 619-632. Tian Zhiping, Jiang Dapang, Zhang Ran, et al. 2012. Long-term climate simulation of CCSM4.0 and evaluation of its performance over East Asia and China (in Chinese)[J]. Chinese J. Atmos. Sci., 36(3): 619-632. DOI:10.3878/j.issn.1006-9895.2011.11092 王志远, 刘健, 王晓青, 等. 2016. 地球系统模式CESM1.0对太阳辐射和温室气体的敏感性差异研究[J]. 第四纪研究, 36(3): 758-767. Wang Zhiyuan, Liu Jian, Wang Xiaoqing, et al. 2016. Divergent sensitivity of Earth System Model CESM 1.0 to solar radiation versus greenhouse gases (in Chinese)[J]. Quaternary Sciences, 36(3): 758-767. DOI:10.11928/j.issn.1001-7410.2016.03.24 赵天保, 陈亮, 马柱国. 2014. CMIP5多模式对全球典型干旱半干旱区气候变化的模拟与预估[J]. 科学通报, 49(12): 1148-1163. Zhao Tianbao, Chen Liang, Ma Zhuguo. 2014. Simulation of historical and projected climate change in arid and semiarid areas by CMIP5 models (in Chinese)[J]. Chinese Science Bulletin, 49(4): 412-429. DOI:10.1007/s11434-013-0003-x Zhao T B, Dai A G. 2015. The magnitude and causes of global drought changes in the twenty-first century under a low-moderate emissions scenario [J]. J. Climate, 28(11): 4490-4512. DOI:10.1175/JCLI-D-14-00363.1 Zhao T B, Dai A G. 2016. Uncertainties in historical changes and future projections of drought. Part Ⅱ:Model-simulated historical and future drought changes [J]. Climatic Change. DOI:10.1007/s10584-016-1742-x Zhao T B, Li C X, Zuo Z Y. 2016. Contributions of anthropogenic and external natural forcings to climate changes over China based on CMIP5 model simulations [J]. Science China Earth Sciences, 59(3): 503-517. DOI:10.1007/s11430-015-5207-2