# 地表以下虚假的风场资料对北半球夏季Hadley环流空间模态及下沉支未来预估的影响Influences of False Subsurface Wind Data on Spatial Pattern of the Northern Hadley Circulation and Future Estimation of the Sinking Branch in Boreal Summer

DOI: 10.12677/CCRL.2020.91001, PDF, HTML, XML, 下载: 223  浏览: 333  国家自然科学基金支持

Abstract: Based on monthly data of wind field from 12 Coupled Model Intercomparison Project Phase 5 (CMIP5) models and the stream function of meridional circulation derived from the three-pattern decomposition global atmospheric circulation method (3P-DGAC), we investigate influences of false subsurface wind data on spatial pattern of the Northern Hadley circulation (HC) and future estimation of the sinking branch in boreal summer. It is found that errors caused by false subsurface wind data are passed to the stream function in the whole layer by vertically integrated process, which could lead to a false “minor circulation” embedded within Northern Hemispheric Hadley circulation (NHHC) in summer. The “minor circulation” would cause miscalculation of the location of the NHHC sinking branch, and it also has a significant effect on the accurate calculation of poleward expansion trend of NHHC. The result of the quantitative analysis shows that, in the 2040-2099 period under Representative Concentration Pathway 8.5 (RCP8.5) scenarios, the false wind data would lead to an overestimation of the poleward expansion trend of NHHC in summer.

1. 引言

2. 资料与方法介绍

2.1. 资料

Table 1. Description of the 12 coupled climate models participating in the CMIP 5

2.2. 方法

$\psi =\frac{2\text{π}a\mathrm{cos}\phi }{g}{\int }_{{P}_{s}}^{P}\left[{v}_{H}\right]\text{d}p$ (1)

3. 结果分析

Figure 1. The uncorrected climatological characteristics of the Northern Hemispher Hadley circulation represented by the stream function ψ in Equation (1) in boreal July (1979-2005)

Figure 2. The corrected climatological characteristics of the Northern Hemispher Hadley circulation represented by the stream function ψ in Equation (1) in boreal July (1979-2005)

Figure 3. The difference between the uncorrected and corrected global zonally averaged vH in the Northern Hemisphere in boreal July (1979-2005)

Figure 4. The difference between the corrected and uncorrected stream function ψ of the Northern Hemispher Hadley circulation in boreal July (1979-2005)

Figure 5. The annual characteristics of the intensity (unit: 2 × 1010 kg∙s−1) of global zonally averaged Hadley circulation before and after error correction (1979-2005), the error bars represent 95% confidence interval

(a) (b)

Figure 6. The annual characteristics of the rising/sinking branch (a) and width (b) of global zonally averaged Hadley circulation before and after correction (1979-2005), the error bars represent 95% confidence interval

Figure 7. Month-latitude plots of the climatological characteristics of stream function ψ (contours, unit: 0.5 × 1010 kg∙s−1) and its future trend (color shading, unit: 0.5 × 1010 kg∙s−1 per decade) at 500 hPa (2040-2099) under RCP8.5 scenario before (a) and after error correction (b). Black dots in (a) and (b) represent the trend has passed 95% statistical significance test

4. 结论