# Height Variation in the Summer Quasi-Zero Wind Layer over Dunhuang, Northwest China: A Diagnostic Study

## 敦煌夏季准零风层高度变化的诊断分析

• Corresponding author: Yi LIU, liuyi@mail.iap.ac.cn
• Funds:

Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA17010105), Science and Technology Development Plan Project of Jilin Province (20180201035SF), Flexible Talents Introducing Project of Xinjiang (2019), and National Key Scientific and Technological Infrastructure Project “Earth System Numerical Simulation Facility” (EarthLab)

• doi: 10.1007/s13351-022-1207-2
• This study investigates the variation in the stratospheric quasi-zero wind layer (QZWL) over Dunhuang, Gansu Province, China, on 9 August 2020 using sounding observations from the Dunhuang national reference station and the fifth generation of ECMWF atmospheric reanalysis data (ERA5). The QZWL over Dunhuang was located between 18.6 and 20.4 km on 9 August 2020. The South Asian high (SAH) and subtropical westerly jet jointly affected the QZWL. As the SAH retreated westward, the upper-level westerly jet over Dunhuang strengthened, and the jet axis height increased. As a result, the zonal westerly wind was lifted to a higher altitude, and the wind speed of 100–70 hPa increased, raising the QZWL. In addition, the east–west oscillation of the SAH occurred earlier than the adjustment of the QZWL altitude, which can be used as a forecasting indicator for the QZWL. To further explore the mechanism responsible for the QZWL adjustment, the forcing terms in the equations for zonal wind, kinetic energy, and vertical wind shear were analyzed. The results showed that the upper-level geopotential gradient was the basic physical factor forcing the local change in zonal wind and kinetic energy. The change in zonal wind and kinetic energy led to the uplift of the QZWL. The results revealed that the vertical shear of horizontal wind could adequately indicate the stratospheric QZWL location.
利用敦煌国家基准站的高空气象探测数据和ERA5逐小时再分析资料，使用诊断分析方法，对2020年8月9日发生在敦煌上空的一次准零风层的高度变化过程进行了分析。2020年8月9日敦煌上空准零风层高度介于18.6–20.4 km之间，受到南亚高压和副热带西风急流的共同作用。随着南亚高压西退，敦煌上空西风急流增强，急流轴高度升高，导致其上方100–70 hPa的风速增大，使准零风层高度抬升。此外，发现南亚高压的东西向振荡的发生早于准零风层高度的变化，可作为准零风层的预报和预测指标之一。诊断分析结果表明，高层位势高度场梯度是引起纬向风和动能变化的最基本物理因素，纬向风和动能的局地变化导致了准零风层高度的抬升，同时水平风速垂直切变能够较好地反映准零风层的位置。
• Fig. 1.  Location of the Dunhuang national reference station, where the asterisk indicates the sounding station.

Fig. 2.  Temporal and vertical cross-section at the Dunhuang national reference station from 24 July to 21 August 2020. (a) Full wind speed (shading; m s−1), (b) pressure disturbance (shading; hPa), (c) temperature disturbance (shading; °C), and (d) density disturbance (shading; 10−5 kg m−3). The black dotted lines denote the heights of 18 and 25 km, respectively. The black solid lines denote the upper and lower boundaries of the QZWL (m s−1).

Fig. 3.  Cross-section of the intensity of the SAH at 100 hPa over Dunhuang from 24 July to 21 August 2020 (the shaded part represents geopotential height; dagpm). (a) Cross-section along 40.15°N (the black dotted line indicates the longitude of Dunhuang) and (b) cross-section along 94.68°E (the black dotted line indicates the latitude of Dunhuang).

Fig. 4.  Wind speed profiles over Dunhuang from 24 July to 21 August 2020 (the gray shaded part is the area of the QZWL and the color shaded part is the minimum total wind speed; the blue solid line is the average height of the QZWL and the yellow solid line is the maximum wind speed of the westerly jet).

Fig. 5.  Time–height profile of vertical shear of the total wind speed (10−2 m s−2) over Dunhuang from 24 July to 21 August 2020.

Fig. 6.  Full wind speed (m s−1) above Dunhuang national reference station from 24 July to 21 August 2020 based on (a) radiosonde data and (b) ERA5 data.

Fig. 7.  Evolution of the forcing terms of (a) the zonal motion equation (units of B and A are 10−3 m s−2 and 10−4 m s−2, respectively) and (b) kinetic energy equation (units of H1, H2, and H3 are 10−2 m2 s−3, 10−3 m2 s−3, and 10−3 m2 s−3, respectively) of 70 hPa over Dunhuang from 1400 BT 8 to 2000 BT 9 August 2020, based on ERA5 data.

Fig. 8.  Distributions of (a–d) geopotential height (dagpm), and (e–h) its zonal (10−4 dagpm m−1) and (i–l) meridional gradient (10−4 dagpm m−1) at 70 hPa over Dunhuang from 8 to 9 August 2020, based on the ERA5 data.

Fig. 9.  Time–height profile of $\dfrac{\partial }{{\partial t}}\left( {\dfrac{{\partial u}}{{\partial p}}} \right)$ in Eq. (3) over Dunhuang from 24 July to 21 August 2020 (the black line is the strength of the SAH at 100 hPa, based on ERA5 data).

Fig. 10.  Contribution of each compulsion item [(a) H (10−8 m Pa−1 s−2), (b) U (10−9 m Pa−1 s−2), (c) L (10−9 m Pa−1 s−2), and (d) W (10−10 m Pa−1 s−2)] in Eq. (4) over Dunhuang at 70 hPa at 0200 BT 9 August 2020, based on ERA5 data.

Fig. 11.  Contribution and total income and expenditure of each forced term in Eq. (4) over Dunhuang at 70 hPa at 0200 BT 9 August 2020, based on ERA5 data; from left to right, the units are as follows: 10−8 m Pa−1 s−2, 10−8 m Pa−1 s−2, 10−9 m Pa−1 s−2, 10−9 m Pa−1 s−2, and 10−10 m Pa−1 s−2.

Fig. 12.  (a–d) Potential temperature (K) and (e–h) its zonal gradient distribution (K m−1) of 70 hPa over Dunhuang from 8 to 9 August 2020, based on ERA5 data.

•  [1] Abalos, M., B. Legras, and E. Shuckburgh, 2016: Interannual variability in effective diffusivity in the upper troposphere/lower stratosphere from reanalysis data. Quart. J. Roy. Meteor. Soc., 142, 1847–1861. doi: 10.1002/qj.2779. [2] Baldwin, M. P., L. J. Gray, T. J. Dunkerton, et al., 2001: The quasi-biennial oscillation. Rev. Geophys., 39, 179–229.. [3] Belmont, A. D., D. G. Dartt, and G. D. Nastrom, 1975: Variations of stratospheric zonal winds, 20–65 km, 1961–1971. J. Appl. Meteor., 14, 585–594.. [4] Camp, C. D., and K. K. Tung, 2007: Surface warming by the solar cycle as revealed by the composite mean difference projection. Geophys. Res. Lett., 34, L14703.. [5] Chen, B. Q., 2018: Characteristics of spatial-temporal distribution of the stratospheric quasi-zero wind layer in China. Ph.D. dissertation, Nanjing University of Information Science & Technology, Nanjing, 85 pp. (in Chinese) [6] Chen, B. Q., Y. Liu, L. K. Liu, et al., 2018: Characteristics of spatial–temporal distribution of the stratospheric quasi-zero wind layer in low-latitude regions. Climatic Environ. Res., 23, 657–669. . (in Chinese) [7] Chen, W., and R. H. Huang, 2002: The propagation and transport effect of planetary waves in the Northern Hemisphere winter. Adv. Atmos. Sci., 19, 1113–1126.. [8] Chen, W., and T. Li, 2007: Modulation of northern hemisphere wintertime stationary planetary wave activity: East Asian climate relationships by the Quasi-Biennial Oscillation. J. Geophys. Res. Atmos., 112, D20120.. [9] Chen, W., M. Takahashi, and H.-F. Graf, 2003: Interannual variations of stationary planetary wave activity in the northern winter troposphere and stratosphere and their relations to NAM and SST. J. Geophys. Res. Atmos., 108, 4797.. [10] Flohn, H., 1957: Large-scale aspects of the “summer monsoon” in South and East Asia. J. Meteor. Soc. Japan, 35A, 180–186.. [11] Garfinkel, C. I., and D. L. Hartmann, 2007: Effects of the El Niño–Southern Oscillation and the Quasi-Biennial Oscillation on polar temperatures in the stratosphere. J. Geophys. Res. Atmos., 112, D19112.. [12] Hersbach, H., B. Bell, P. Berrisford, et al., 2020: The ERA5 global reanalysis. Quart. J. Roy. Meteor. Soc., 146, 1999–2049. doi: 10.1002/qj.3803. [13] Holton, J. R., and R. S. Lindzen, 1972: An updated theory for the quasi-biennial cycle of the tropical stratosphere. J. Atmos. Sci., 29, 1076–1080.. [14] Holton, J. R., and H.-C. Tan, 1980: The influence of the equatorial quasi-biennial oscillation on the global circulation at 50 mb. J. Atmos. Sci., 37, 2200–2208.. [15] Huang, W. N., X. J. Zhang, Z. B. Li, et al., 2019: Development status and application prospect of near space science and technology. Sci. Technol. Rev., 37, 46–62. (in Chinese) [16] Kinnersley, J. S., 1998: Interannual variability of stratospheric zonal wind forced by the northern lower-stratospheric large-scale waves. J. Atmos. Sci., 55, 2270–2283.. [17] Konopka, P., J.-U. Grooß, G. Günther, et al., 2010: Annual cycle of ozone at and above the tropical tropopause: observations versus simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS). Atmos. Chem. Phys., 10, 121–132.. [18] Labitzke, K., 2005: On the solar cycle–QBO relationship: a summary. J. Atmos. Solar-Terr. Phys., 67, 45–54.. [19] Li, Q. B., J. H. Jiang, D. L. Wu, et al., 2005: Convective outflow of South Asian pollution: A global CTM simulation compared with EOS MLS observations. Geophys. Res. Lett., 32, L14826.. [20] Liu, H. B., L. Dong, R. J. Yan, et al., 2021: Evaluation of near-surface wind speed climatology and long-term trend over China’s mainland region based on ERA5 reanalysis. Climatic Environ. Res., 26, 299–311. (in Chinese) [21] Liu, Y., and C.-H. Lu, 2010: The influence of the 11-year sunspot cycle on the atmospheric circulation during winter. Chinese J. Geophys., 53, 354–364.. [22] Liu, Y., Y. H. Zhao, and Z. Y. Guan, 2008: Influences of stratospheric circulation anomalies on tropospheric weather of the heavy snowfall in January 2008. Climatic Environ. Res., 13, 548–555. (in Chinese) [23] Lyu, D. R., B. L. Sun, and L. Q. Li, 2002: Zero wind layer and the first dwell experiment of high-altitude ballon in China. Target Environ. Feat., 22, 45–51. (in Chinese) [24] Lyu, D. R., Z. Y. Chen, X. Guo, et al., 2009: Recent progress in near space atmospheric environment study. Adv. Mech., 39, 674–682. . (in Chinese) [25] Mason, R. B., and C. E. Anderson, 1963: The development and decay of the 100-mb. summertime anticyclone over southern Asia. Mon. Wea. Rev., 91, 3–12.. [26] O’Neill, A., A. J. Charlton-Perez, and L. M. Polvani, 2015: Middle atmosphere | stratospheric sudden warmings. Encyclopedia of Atmospheric Sciences, 2nd ed., G. R. North, J. Pyle, and F. Q. Zhang, Eds., Elsevier, Amsterdam, 30–40, doi: 10.1016/B978-0-12-382225-3.00230-9. [27] Randel, W. J., and M. Park, 2006: Deep convective influence on the Asian summer monsoon anticyclone and associated tracer variability observed with Atmospheric Infrared Sounder (AIRS). J. Geophys. Res. Atmos., 111, D12314.. [28] Tao, M. C., J. H. He, and Y. Liu, 2012: Analysis of the characteristics of the stratospheric quasi-zero wind layer and the effects of the quasi-biennial oscillation on it. Climatic Environ. Res., 17, 92–102. . (in Chinese) [29] Wang, Y. G., J. Q. Li, Y. Li, et al., 2007: Characters and application prospects of near space flying vehicles. Spacecr. Eng., 16, 50–57. . (in Chinese) [30] Xiao, C. Y., X. Hu, J. C. Gong, et al., 2008: Analysis of the characteristics of the stratospheric quasi-zero wind layer over China. Chinese J. Space Sci., 28, 230–235. . (in Chinese) [31] Ye, D. Z., and J. Q. Zhang, 1974: Simulation test for influence of heating effect of Qinghai-Xizang Plateau to circulation over East-Asia in summer. Sci. China, (3), 301–320. (in Chinese) [32] Yeh, T.-C., S.-W. Lo, and P.-C. Chu, 1957: The wind structure and heat balance in the lower troposphere over Tibetan Plateau and its surrounding. Acta Meteor. Sinica, 28, 108–121. . (in Chinese) [33] Yin, Z. Z., and Q. Li, 2006: Analysis of near space vehicle and its military application. J. Acad. Equip. Comm. Technol., 17, 64–68. . (in Chinese) [34] Zhang, J., 2006: Mesoscale Synoptics. China Meteorological Press, Beijing, 32–46. (in Chinese) [35] Zhang, J. K., F. Xie, Z. C. Ma, et al., 2019: Seasonal evolution of the quasi-biennial oscillation impact on the Northern Hemisphere polar vortex in winter. J. Geophys. Res. Atmos., 124, 12,568–12,586.. [36] Zhang, Y. L., 2015: Stratospheric winter-to-summer seasonal transition and the influences of multi-scale dynamics. Ph.D. dissertation, University of Chinese Academy of Sciences, Beijing, 111 pp. (in Chinese) [37] Zhou, X. J., H. B. Chen, and J. C. Bian, 2011: Analysis of the characteristics of zonal wind reverse layer in the lower and middle stratosphere of the Northern Hemisphere and its seasonal variation. Climatic Environ. Res., 16, 565–576. . (in Chinese)
###### 通讯作者: 陈斌, bchen63@163.com
• 1.

沈阳化工大学材料科学与工程学院 沈阳 110142

## Height Variation in the Summer Quasi-Zero Wind Layer over Dunhuang, Northwest China: A Diagnostic Study

###### Corresponding author: Yi LIU, liuyi@mail.iap.ac.cn;
• 1. School of Environmental Studies, China University of Geosciences, Wuhan 430074
• 2. Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029
• 3. State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, China Meteorological Administration, Beijing 100081
Funds: Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA17010105), Science and Technology Development Plan Project of Jilin Province (20180201035SF), Flexible Talents Introducing Project of Xinjiang (2019), and National Key Scientific and Technological Infrastructure Project “Earth System Numerical Simulation Facility” (EarthLab)

Abstract: This study investigates the variation in the stratospheric quasi-zero wind layer (QZWL) over Dunhuang, Gansu Province, China, on 9 August 2020 using sounding observations from the Dunhuang national reference station and the fifth generation of ECMWF atmospheric reanalysis data (ERA5). The QZWL over Dunhuang was located between 18.6 and 20.4 km on 9 August 2020. The South Asian high (SAH) and subtropical westerly jet jointly affected the QZWL. As the SAH retreated westward, the upper-level westerly jet over Dunhuang strengthened, and the jet axis height increased. As a result, the zonal westerly wind was lifted to a higher altitude, and the wind speed of 100–70 hPa increased, raising the QZWL. In addition, the east–west oscillation of the SAH occurred earlier than the adjustment of the QZWL altitude, which can be used as a forecasting indicator for the QZWL. To further explore the mechanism responsible for the QZWL adjustment, the forcing terms in the equations for zonal wind, kinetic energy, and vertical wind shear were analyzed. The results showed that the upper-level geopotential gradient was the basic physical factor forcing the local change in zonal wind and kinetic energy. The change in zonal wind and kinetic energy led to the uplift of the QZWL. The results revealed that the vertical shear of horizontal wind could adequately indicate the stratospheric QZWL location.

Reference (37)

/