The Third Atmospheric Scientific Experiment
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THE THIRD ATMOSPHERIC SCIENTIFIC EXPERIMENT FOR UNDERSTANDING THE Downloaded from http://journals.ametsoc.org/bams/article-pdf/99/4/757/3750084/bams-d-16-0050_1.pdf by guest on 21 September 2020 EARTH –ATMOSPHERE COUPLED SYSTEM OVER THE TIBETAN PLATEAU AND ITS EFFECTS PING ZHAO, XIANGDE XU, FEI CHEN, XUELIANG GUO, XIANGDONG ZHENG, LIPING LIU, YANG HONG, YUEQING LI, ZUO LA, HAO PENG, LINZHI ZHONG, YAOMING MA, SHIHAO TANG, YIMIN LIU, HUIZHI LIU, YAOHUI LI, QIANG ZHANG, ZEYONG HU, JIHUA SUN, SHENGJUN ZHANG, LIXIN DONG, HEZHEN ZHANG, YANG ZHAO, XIAOLU YAN, AN XIAO, WEI WAN, YU LIU, JUNMING CHEN, GE LIU, YANGZONG ZHAXI, AND XIUJI ZHOU Integrated monitoring systems for the land surface, boundary layer, troposphere, and lower stratosphere over the Tibetan Plateau promote the understanding of the Earth–atmosphere coupled processes and their effects on weather and climate. he Tibetan Plateau (TP), known as the “sensible in the tropics and midlatitudes of the North Pacific heat pump” and the “atmospheric water tower,” (e.g., Zhao and Chen 2001b; Liu et al. 2007; Zhao et al. T modifies monsoon circulations and regional 2007; Nan et al. 2009; Zhao et al. 2009; Zhou et al. energy and water cycles over Asia (Wu and Zhang 2009; Duan et al. 2012). Therefore, global weather 1998; Zhao and Chen 2001a; Wu et al. 2007; Xu et al. and climate research would be incomplete without 2008b; Zhou et al. 2009). Strong ascent over the TP considering the significant role of the TP. may transport lower-tropospheric water vapor and Compared to other land regions in the world, anthropogenic pollutants into the upper troposphere– observational data are scarce over the TP, owing to lower stratosphere (UT–LS), which exerts an influ- its high elevations, naturally harsh environmental ence on the regional ozone valley (Zhou et al. 1995; conditions, and less-developed logistics. Thus, a few Liu et al. 2003; Bian et al. 2011) and the aerosol-layer field experiments have been implemented in the data- enhancements near the tropopause (Tobo et al. 2007; scarce areas. For instance, the first Qinghai–Xizang Vernier et al. 2015). The TP also modulates large- Plateau Meteorology Experiment (QXPMEX) was scale atmospheric circulations over the Northern carried out from May to August 1979 (Tao et al. Hemisphere and atmosphere–ocean interactions 1986). This experiment promoted, for the first time, AMERICAN METEOROLOGICAL SOCIETY APRIL 2018 | 757 systematic research on the diurnal and seasonal varia- Entering the twenty-first century, the Coordinated tions and spatial features of the surface heat budget, Enhanced Observing Period (CEOP) Asia–Australia the structures and evolutions of atmospheric circula- Monsoon Project on the Tibetan Plateau (CAMP/ tion systems over the TP, and their effects on global Tibet), and the Tibetan Observation and Research and Asian general circulations. Platform (TORP) were implemented over the central In the 1990s, a longer-term field experiment was northern TP during 2002–04 (Ma et al. 2006, 2008). conducted over the TP with the support of the Japanese Their research documented regional characteristics of Experiment on Asian Monsoon (JEXAM). It estimated land surface heat and CO2 fluxes, turbulence, and the the drag coefficient Cd of surface momentum and the PBL (Ma et al. 2009). Under the support of the Japan bulk transfer coefficient Ch of surface sensible heat International Cooperation Agency (JICA) project, (SH) and revealed seasonal and interannual varia- a New Integrated Observational System over the tions of the surface heat budget over the TP and their Tibetan Plateau (NIOST) project (JICA/Tibet) was Downloaded from http://journals.ametsoc.org/bams/article-pdf/99/4/757/3750084/bams-d-16-0050_1.pdf by guest on 21 September 2020 relationships with rainy seasons (Chen 1999; Zhao carried out during 2005–09 (Xu et al. 2008a; Zhang and Chen 2000a,b). Afterward, the Second Tibetan et al. 2012; Chen et al. 2011, 2013). It found diurnal Plateau Atmospheric Scientific Experiment (TIPEX-II) variations of rainfall over the TP and effects of latent was carried out from May to August 1998. Its results heat release on TP vortices, provided evidence of showed an imbalance phenomenon of the surface heat strong troposphere–stratosphere exchanges over the budget, strong mesoscale convection activities, and TP, improved the National Oceanic and Atmospheric shear-line characteristics (Chen et al. 1999). The Global Administration/National Centers for Environmental Energy and Water Cycle Experiment (GEWEX) Asian Prediction (NOAA/NCEP)–Oregon State Univer- Monsoon Experiment (GAME)/Tibet intensive obser- sity–Air Force Research Laboratory–NOAA/Office vation conducted a plateau-scale automated weather of Hydrology land surface model (Noah) on the basis station experiment and a mesoscale experiment of of observational characteristics in the land surface the land surface and planetary boundary layer (PBL) energy balance, and revealed the importance of the observations with one X-band Doppler radar at Naqu, deep PBL to the troposphere–stratosphere exchange China, from May to September 1998 (Wang 1999; Ueno over the TP. In the summer of 2011, an experiment of et al. 2001). GAME/Tibet made progress in retrieving the TORP ground-based and airborne remote sens- the land surface radiative budget, precipitation, and ing observations was conducted over the central TP soil moisture from satellite remote sensing products as part of the Global Change Program of China (Ma and understanding the PBL structures, the convec- et al. 2014). This experiment found hydrothermal tive rapid development, and the precipitating cloud and momentum exchanges and moisture transports characteristics (Wang 1999; Ueno et al. 2001; Uyeda over the southeastern TP during the monsoon period, et al. 2001; Choi et al. 2004). as well as land surface and atmospheric circulation AFFILIATIONS: P. ZHAO—State Key Laboratory of Severe of Atmospheric Physics, Chinese Academy of Sciences, Beijing, Weather, Chinese Academy of Meteorological Sciences, China; YA. LI—Lanzhou Institute of Arid Meteorology, China Beijing, and Collaborative Innovation Center on Forecast and Meteorological Administration, Lanzhou, China; Q. ZHANG— Evaluation of Meteorological Disasters, Nanjing University of Beijing Weather Modification Office, Beijing, China; HU—Cold Information Science and Technology, Nanjing, China; XU, GUO, and Arid Regions Environmental and Engineering Research Insti- ZHENG, L. LIU, PENG, ZHONG, S. ZHANG, Y. ZHAO, XIAO, YU LIU, tute, Chinese Academy of Sciences, Lanzhou, China; SUN—Yun- J. CHEN, G. LIU, AND ZHOU—State Key Laboratory of Severe nan Provincial Meteorological Bureau, Yunnan, China; WAN— Weather, Chinese Academy of Meteorological Sciences, Beijing, State Key Laboratory of Hydroengineering, and Department of China; F. CHEN—State Key Laboratory of Severe Weather, Hydraulic Engineering, Tsinghua University, Beijing, China Chinese Academy of Meteorological Sciences, Beijing, China, CORRESPONDING AUTHORS: X. D. Xu, [email protected]; and National Center for Atmospheric Research, Boulder, P. Zhao, [email protected] Colorado; HONG—National Weather Center, and School of The abstract for this article can be found in this issue, following the Civil Engineering and Environmental Sciences, University of table of contents. Oklahoma, Norman, Oklahoma; YU. LI—Chengdu Institute of DOI:10.1175/BAMS-D-16-0050.1 Plateau Meteorology, China Meteorological Administration, Chengdu, China; LA, H. ZHANG, AND ZHAXI—Meteorological In final form 31 October 2017 ©2018 American Meteorological Society Bureau of Tibet Autonomous Region, Lhasa, China; MA—Insti- For information regarding reuse of this content and general copyright tute of Tibetan Plateau Research, Chinese Academy of Sciences, information, consult the AMS Copyright Policy. Beijing, China; TANG AND DONG—National Satellite Meteoro- This article is licensed under a Creative Commons logical Center, Beijing, China; YI. LIU, H. LIU, AND YAN—Institute Attribution 4.0 license. 758 | APRIL 2018 variations against the background of global change. are not well understood. Moreover, because of the Moreover, the Tibetan Plateau: Formation–Climate– scarce radiosonde data over the western TP, it is not Ecosystems (TiP) program focused on a longer-term known how the local atmospheric circulation systems evolution of climate over the TP and its influence (especially synoptic- and mesoscale systems) develop (Mosbrugger and Appel 2012). and move from the west to the east. Thus, numeri- To quantify uncertainties in satellite and model cal weather and climate forecast models often have products of soil moisture and temperature, some poor reliability when modeling weather and climate regional-scale observation networks were established. features over the TP, including soil moisture, surface For example, during 2008–13, the CEOP–Asian- heat fluxes, surface air temperature, rainfall, PBL Monsoon System with Ground Satellite Image Data structures, cloud amount, and stratospheric ozone and Numerical Simulations (AEGIS) project moni- (Wang 2011; Wu and Zhou 2011; Qiu et al. 2013; tored the land surface characteristics and analyzed Hu et al. 2014; Zheng et al. 2014, 2015a,b,c, 2016; Downloaded from http://journals.ametsoc.org/bams/article-pdf/99/4/757/3750084/bams-d-16-0050_1.pdf by guest on 21 September 2020 their linkages with convection, precipitation, and Guo et al. 2015; Zhuo et al. 2016; Wan et al. 2017). Asian monsoons by satellites, the existing ground- These problems may also cause large