Abstract:The summer monsoon rainband in East China and its northward seasonal leap in relation to conditional symmetric instability (CSI) during the period of 1981 to 2010 is diagnosed through computing and analyzing moist potential vorticity (MPV) flux,CSI, slantwise convective available potential energy (SCAPE), and a newly developed index of conditional MPV flux (CMF). The European Centre for Medium-Range Weather Forecasts reanalysis data and daily precipitation data collected at 741 stations in China are used. Monthly-averaged anomaly fields show the northward leap of heavy rainfall center from South China in April to June to the Yangtze-Huaihe region in May to July and to North China in July to August. The spatial pattern of more precipitation in North China and less precipitation to the South of the Yangtze-Huaihe during July to August is well represented by the rainfall anomaly field than by the mean field. The negative MPV flux is in phase with the northward leap of heavy rainfall from South China (April to June) to North China (July to August). CSI zones within the rainband center are mainly located between 925 and 600 hPa in April, May and September, whereas they vertically shift to 700-600 hPa from June to August. The CSI zones are also a good indicator of the northward leap of summer monsoon rainband and its intensification as well as its southward retreat and weakening. During the late spring and early summer when the monsoon starts, the thermal wind contribution to SCAPE is dominant over the contribution of CAPE in the magnitudes, whereas the opposite is true from July to August. Furthermore, the thermal wind contribution is in phase with the northward seasonal leap of heavy rainfall from South China in April to June to Yangtze-Huaihe in May to July and to North China in July to August, while CAPE has no such relationship with the heavy rainfall center. The CMF index can be an indicator for the regional summer rainfall anomaly in East China.

Abstract:An extreme precipitation event occurred during 31 July to 1August, 2016, at the Yili River Valley that broke multi-station single-event precipitation records. Based on calculations of (1) the water vapor transport stream function and non-divergent (rotational) components, (2) potential function and divergent (irrotational) components, (3) the water vapor transport budget using 1°×1° NCEP/NCAR reanalysis, and (4) water vapor transport trajectories using the HYSPLIT model based on the Lagrangian method, the large-scale water vapor transport and convergence characteristics were analyzed during the heavy rainfall period. The results showed that: (1) The Atlantic Ocean and the Red Sea contributed to the water supply during the event, with the Indian summer monsoon circulation at low latitudes, and the Atlantic Ocean’s east airflow at mid-latitudes, constituting the water vapor transmission channel; convergence and orographic uplift of the terrain to the west provided a favorable dynamic convergence mechanism for the occurrence of locally heavy rain. (2) The 3000 m water vapor transmission trajectory included westward and eastward paths at the bottom layer,and the northward path at mid-troposphere, as streams of water vapor for the lower troposphere through vertical motion; the southward lower-tropospheric path provided water vapor from the Arabian Sea, while the mid-latitude water vapor transport from the west was the most powerful; The 5000 m water vapor transmission trajectory was dominated by the westward path and the low-pressure trough itself. (3) During the precipitation period, water vapor was concentrated in the lower troposphere, which was transported to the upper levels through vertical motion. The water vapor inflow from the southernmost boundary was rapidly increasing at the lower layers, while the middle and upper layer water vapor inflow derived from the western boundary. (4) Yili River Valley GPS-precipitable water vapor (PWV) values jumped due to the southwest airflow around the upper trough before the rainfall occurred, and remained high due to the influence of the Indian Southwest Monsoon during the heavy rainfall period.

Abstract:A vortex initialization scheme has been developed and implemented in a newly updated version of GRAPES-TCM (Global/Regional Assimilation and Prediction System-Tropical Cyclone Model) by following the principle of HWRF (Hurricane Weather Research and Forecasting Model), in which correction for the vortex is as small as possible. The new scheme applies a small correction in the storm vortex to maintain a certain consistency with the model. Arbitrariness in the modification of the vortex is largely reduced, and the resultant vortex holds related dynamical and thermodynamical balance. Results indicate that the initial vortex from the new scheme possesses an intensity that is considerably closer to the observed intensity and increased structural detail. Hindcast shows that the new vortex scheme can effectively improve the accuracy of typhoon tracking and intensity forecasting.

Abstract:Based on the ERA-Interim reanalysis data provided by the European Centre for Medium Range Weather Forecasts (ECMWF), in this study, we estimated atmospheric apparent heat sources using a thermal equation. We investigated the interdecadal change in the relation between the atmospheric apparent heat sources over the Tibetan Plateau in summer and the summer precipitation in eastern China, and the mechanism of the impact of these heat sources on the summer precipitation in eastern China. We found the variance in the west-east dipole mode of the atmospheric apparent heat sources over the Tibetan Plateau in summer to exhibit an interdecadal increase, which illustrates the increasing importance of the west-east dipole mode from the second leading mode prior to 1994 to the first mode after 1994. The relationship between the atmospheric apparent heat sources over the Tibetan Plateau and precipitation in eastern China exhibited interdecadal changes around 1994 and 2007. The summer abnormal heat sources over the Tibetan Plateau are closely related only to the precipitation anomalies over the lower reaches of the Yangtze River prior to 1993 and those over the middle Yangtze River after 2008, but are related to the summer precipitation in the Yangtze River Basin and adjacent and southern China regions from 1994-2007. Specifically, the strong (weak) heat sources over the eastern Plateau in summer correspond to abundant (scarce) precipitation over the upper and middle reaches of the Yangtze River and the Huaihe River Basin, with less (more) rainfall in southern China. We found the atmospheric apparent heat sources over the Tibetan Plateau to influence the summer precipitation in the Yangtze River Basin and adjacent regions mainly through the eastward movement of the weather systems that develop as they pass over the Plateau, as well as the precipitation in southern China through anomalous vertical circulation.

Abstract:Daily precipitation data from 447 stations in eastern China were used to discuss the spatio-temporal characteristics of different grades of precipitation during the period of 1980-2013. Correlations between light rain and lower tropospheric temperature (LTT), lower tropospheric water vapor content (LTW), and lower tropospheric relative humidity (LTRH) were subjected to EOF and composite analyses. The contributions of warming and the variation in relative humidity to the decrease in light rain were clarified by using the Clausius-Clapeyron equation. The characteristics of the reduction in light rain over the Yangtze River Delta were also analyzed on the basis of daily visibility data. The following results were obtained: (1) Annual mean precipitation days and precipitation amount over eastern China declined with increasing latitude, and light rain days (LRD) provided the major contribution to all rainfall days, and accounted for 71.84% of all rainfall days. Different grades of rain, except for storms, all tended to decrease, and LRD and light rain amount (LRA) distinctly decreased at the rates of -3.37 d (10 a)^-1 and -6.52 mm (10 a)^-1, respectively. The first mode of EOF for LRD showed the reduction of LRD over the whole study region, whereas the second mode showed distinct spatial differences. (2) The reduction in light rain was accompanied by lower tropospheric warming. LTT increased at the rate of 0.32 K (10 a)^-1. By contrast, LTW slightly decreased. The positive correlations of the variation in light rain with LTRH indicated that the spatial characteristic of LTRH was similar to that of light rain revealed by EOF analysis. The results of composite analysis suggested that light rain was low (high) in the year of high (low) LTT, and high (low) in the year of high (low) LTRH and high (low) LTW. (3) Calculations obtained by using the Clausius-Clapeyron equation and the relative humidity equations revealed that the saturation vapor content increased by 6% K^-1 to 7% K^-1 as a result of lower tropospheric warming, which induced the distinct decrease in the LTRH given the negligible change in lower tropospheric specific humidity and ultimately reduced light rain. The effects of LTT and lower tropospheric specific humidity on the changes in light rain suggested that the 4.83% reduction in light rain was caused by LTT only, whereas the 1.91% reduction in light rain was caused by lower tropospheric specific humidity only. (4) Although annual mean LRA and LRDs were considerably low in regions with low visibility, the long-term reduction in light rain induced by the decrease in LTRH was attributed to lower tropospheric warming.

Abstract:Based on TBB data from FY2E (2010-2014) and FY2G (2015-2016), the gauge-adjusted CMORPH hourly precipitation and daily gauge observations, statistical characteristics of eastward propagation of cloud clusters from the Tibetan Plateau (TP) and Mesoscale Convective Systems (MCS) embedded in these cloud clusters in the summers of 2010-2016 are analyzed. The results show that there are 120 eastward propagation processes accompanied with precipitation over the downstream region (east of 104°E). Most of these processes occurred in June, but those with longer durations more frequently occurred in July. Cloud clusters follow three prominent tracks to propagate from the TP to the middle-lower reaches of Yangtze River basin: 1. propagating eastward directly, 2. propagating along the Yangtze River, during which the cloud clusters first move southeastward and then turn eastward, and 3. propagating along complicated paths. The cloud clusters propagating along the second track has the highest impact due to their high occurrence frequency (46 processes), long duration and the most rainy days (heavy rain days) over the downstream region. The MCSs embedded in these eastward-propagating cloud clusters occur most frequently in July and more frequently over the eastern slope of TP, eastern part of Yunnan-Guizhou Plateau and the Yangtze River basin. The MCSs over the TP can only affect rainfall over the downstream region after they propagate eastward. This is because even the long-lived Meso-α Convective Systems (MαCS) with longer moving tracks over the TP or the eastern slope of TP cannot reach the region east of 110°E. The diurnal cycles of the Permanent Elongated Convective System (PECS) over different regions show that they propagate downstream more easily during the night. The MCSs embedded in the cloud clusters that follow the second track to propagate eastward are the most and also develop most robustly over the downstream region. They are highly associated with heavy rainfall events and areas affected by heavy rainfall.

Abstract:Based on the ERA-Interim reanalysis data and the HYSPLIT (hybrid single particle Lagrangian integratedtrajectory) model driven by the NOAA reanalysis data, this study examined the dynamical process and moisture source ofa heavy precipitation event that occurred in southern Xinjiang on 24 May 2015. The results indicated that the directinfluencing system of this heavy precipitation was the small perturbation along the southwesterly flow east of the centralAsian low vortex. The enhanced upper divergence pumping action caused by the two upper-level jets and the coupling ofthe upper- and low-level jet streams induced deep and intense ascending motions, which was the main dynamic upliftmechanism of the heavy precipitation. The evolution of TBB (black body temperature) corresponded well with theoccurrence and development of precipitation; the rainfall occurred when the low value center of TBB dropped below-50℃ and strengthened continually with the expansion of the low value center. A further study suggested that thepositive center of the vertical component of CVV (convective vorticity vector) at 850 hPa could roughly reflect thelocation of the heavy precipitation 6 to 12 hours ahead. Analysis of the moisture flux and trajectory tracking revealed thatthe most significant moisture sources of the heavy precipitation over the basin in southern Xinjiang were the Black Seaand the Caspian Sea, and the low-level jet entrained a part of moisture into the south of Xinjiang. The result of HYSPLITmodel tracking illustrated that two moisture paths both originated from Eurasia but differed in trajectories during theheavy precipitation; the moisture above and below 800 hPa was mainly transported by the western track and diversiontrack separately. Significant uplift occurred vertically in both trajectories before heavy precipitation, and the convergenceof moisture contributed to the event．

Abstract:Red sprites are a type of TLEs (Transient Luminous Events) that occur above energetic thunderstorms. TLEs are produced by cloud-to-ground lightning strokes or interaction with continuous current, and manifest a direct coupling relation between the troposphere and lower ionosphere. In mainland China, red sprites are mainly observed in the north. To further study red sprites in the middle and high latitude areas of China and reveal their relation with parent lightning and thunderstorms, the authors conducted an observation experiment in the suburb of Liaoyuan City, Jilin Province in the summer of 2017. In this paper, the authors introduce red sprite events captured by a low-light video camera system in Northeast China. Combined with lightning locations, weather radar, and other synchronized observation data, the authors analyzed the characteristics of red sprites and their parent thunderstorms. The results show that 17 (about 2/3) of the 26 observed red sprite events occurred over a large-scale MCS (Mesoscale Convective System), and the remainder (about 1/3) were induced by three relatively small-scale MCSs. The sprite-producing lightning strokes were located at the edge of the convective core region, and the authors observed no large-scale stratiform cloud precipitation areas behind the MCS convection regions. Electromagnetic pulse signals recorded simultaneously in Liaoyuan (Jilin Province) and Hefei (Anhui Province) stations indicate that all the observed red sprites were generated by positive cloud-to-ground lightning strokes.

Abstract:Based on monthly reanalysis data from the JRA-55 (Japanese 55-year Reanalysis) during the period 1958-2016, the northern edge of the East Asian Summer Monsoon (EASM) is defined by the Precipitable Water (PW) in summer. In this study, the authors used harmonic decomposition, regression analysis, composite analysis, wave activity flux analysis, and other analytical methods to study the interannual variation of the displacement of the northern edge of the EASM. The results show a dramatic west-to-east discrepancy with independent variations over North China (107.5°-115°E) and Northeast China (122.5°-130°E), which are related to an anticyclonic moisture circulation anomaly to the east. The discrepancy related to the location of northern edge in North China lies over the Yellow Sea, and that of Northeast China lies over the northern Sea of Japan. As a result, these two regions experience enhanced transport of southerly moisture and moisture convergence. The abnormal anticyclonic circulation influencing North China is related to the propagation of wave trains in the upper-troposphere mid-high latitudes from the east of Europe. The abnormal anticyclonic circulation affecting Northeast China is due to the asymmetry between the southward-displaced and northward-displaced monsoon edge conditions. The former might be related to the northward propagation of abnormal signals from low latitudes via the East Asia-Pacific teleconnection, whereas the latter might be related to the positive geopotential height anomaly caused by local warming over northeastern Asia.

Abstract:Atlantic Multi-decadal Oscillation (AMO) is the average sea surface temperature (SST) over the entire North Atlantic after the long-term warming trend is removed. In the reconstruction of North Atlantic SST from the mid-1800s to present, the basin-wide mean time series appears to oscillate with a period of 50-80 years. One of the most accepted theories is that the AMO is primarily driven by variation in the strength of Atlantic meridional overturning circulation (AMOC). Recently, the atmosphere-forced thermodynamics for the AMO has been proposed. There is a clear need to figure out the causality between AMO and North Atlantic surface heat flux and it may provide a key feature to distinguish the AMO mechanisms. We use a newly developed technique that is based on the information flow concept to investigate the causal structure between the North Atlantic surface heat flux and the observed AMO from the mid-1800s. Our study shows one-way causality between North Atlantic surface heat flux and AMO. It is confirmed that the AMO is the main causal driver of the North Atlantic surface heat flux, which means ocean dynamics mainly dominates heat transport between ocean and atmosphere. The stochastic atmosphere-forced thermodynamics mechanism cannot explain the results. The results between the AMO and land surface air temperature further prove that the AMO dominates the North Atlantic surface heat flux transport. We conduct a SST forced ATL_VAR_AGCM experiment, and the results of the five ensemble members from the experiment verified the direct impact of the Atlantic SST forcing on land surface air temperature. The results of this study provide a new clue to distinguish the AMO mechanisms and further show that, instead of atmosphere-forced thermodynamics mechanism, ocean circulation may mainly drive the AMO.

Abstract:In order to study microphysical characteristics and changes of snowfall in Nanjing, observations of the second-generation laser raindrop spectrometer PARSIVEL² and automatic weather stations and MICAPS data are used to analyze microphysical parameters of snowflakes in Nanjing in the winter of 2018. The results are as follows. (1) It can be seen that there was a conversion from small snowflakes to large snowflakes when the snowfall intensity in Case 1 increased, while significant increases in the snowflake concentration occurred in the other three processes. The difference in temperature makes the snow formation mechanism in Case 1 different from that in the other three cases, which eventually led to a stable snowfall stage, and the mechanisms for snow intensity increases are different. (2) Gamma distribution and M-P distribution are used to fit different stages of the four snowfalls respectively; the analysis shows that the goodness of fit using the Gamma distribution is higher than that using the M-P distribution at all stages, and the goodness of fit of the snowfall termination stage is lower than that of the initial stage and the entire process of snowfall. The Gamma distributions of the snow particle spectra for the four snowfalls are: N＝107D^-0.21exp(-0.54D), N＝136D^-0.54exp(-0.60D), N＝256D^0.38exp(-1.01D), N＝9.39×10⁴D⁴exp (-7.81D) (N is snowfall particle number concentration and D is snowflake diameter). (3) There are two peaks in the velocity spectrum for Case 1 at about 3 mm, which are close to the frosted and unfrosted curves respectively, indicating that there are two forming mechanisms for the snowfall. (4) Considering Case 1, 2, and 3, the comprehensive Z-I relationship for strong snowfalls during the period of stable stage of the stratiform cloud system in Nanjing is Z＝1708I^1.51.

Abstract:In this study, the authors investigated the interdecadal change characteristics of the extreme precipitation (days of extreme precipitation: R95p; contribution rate of extreme precipitation: R95t) in summer in ENC (East northern China) during the period 1961-2016, as well as the differences in the atmospheric circulation and transport of water vapor for extreme and ordinary precipitation. The results show that both R95p and R95t have decreased significantly since 2000. Compared with the period 1984-1999, in 2000-2016, there were three circulation anomaly centers located in the Eurasian, Central Asian, and Northeast China-Mongolian areas, which exhibited a “positive-negative-positive” wavelike structure that caused a predominant and positive barotropic anomaly over ENC. A positive high geopotential anomaly with a sinking movement is unfavorable for the occurrence of extreme precipitation in ENC. The negative phase of the Pacific Decadal Oscillation (PDO) and the positive phase of the Atlantic Multidecadal Oscillation (AMO) have jointly reinforced positive anomalies in the geopotential height over ENC. The research results further reveal that there have been significant differences in the water-vapor transport and the key local circulation systems of extreme and ordinary precipitation events. Compared with ordinary precipitation, the water-vapor transport and budget for extreme precipitation from south to north were stronger. In addition, the ENC area was controlled by a stronger closed low-pressure system, which could have been enhanced by descending air with high potential vorticity during the occurrence of extreme precipitation.

Abstract:To investigate possible impact of sea surface temperature (SST) change on surface rainfall process of tropical cyclone（TC） Soudelor over the ocean, sensitivity experiments are conducted using the Weather Research Forecasting (WRF) model and a 3D WRF-based precipitation equation based on the previous study of Wang et al. (2018). SST in the control experiment (CTL experiment, SST changes with time) is much different to SST in the sensitivity experiment (SNC experiment, SST remains constant). The results show that the difference in the simulated TC track over the ocean is small in the two experiments, but the simulated TC intensity in the SNC experiment is stronger than that in the CTL experiment. For the TC circulation, differences in the vertical velocity between the two experiments are basically positive in the troposphere (the SNC experiment yields stronger updrafts than the CTL). As the difference in SST increases, the vertical motion difference also becomes larger. Precipitation rate (P_S )in the SNC experiment is larger than that in the CTL experiment, but the difference in P_S between the two experiments increases non-linearly with the SST difference, which reflects the complexity of P_S variation. Q_WVA (the three-dimensional moisture flux convergence or divergence rate) in the SNC experiment is basically larger than that in the CTL experiment (especially in the later period of the TC life cycle). This is because SST difference can affect vertical motion and cause Q_WVA difference, which in turn affects P_S. During the study period of the two experiments, the atmosphere inside the TC continuously becomes drier (positive Q_WVL), and evaporation from the sea surface (positive Q_WVE) is significant._. There is little difference in Q_WVL between the two experiments. However, Q_WVE in the SNC experiment is generally stronger than that in the CTL experiment (especially in the middle and later stages of the TC life cycle). Temporal variations of the change rate of hydrometeor-related processes in the two experiments are complicated, but the magnitude of the maximum difference is comparable to that of Q_WVE. SST affects the growth of cloud hydrometeors content and deep convection, and thus differences in the variation of hydrometeors content gradually increased with SST difference between the two experiments. Among liquid-phase hydrometeors, large difference is found in raindrops, while differences in ice-phase hydrometeors, particularly large ice particles (snow and graupel), are even greater. In the SNC experiment, more graupel particles and raindrops are concentrated below the melting layer, which, concomitant with stronger updrafts, contribute to the occurrence and enhancement of P_racw(accretion of cloud water by rain) and P_gmlt（melting of graupels） and eventually enhance precipitation. Comparative analysis of regionally and temporally averaged macroscopic and microphysical processes related to the TC rainfall between the CTL and SNC experiments shows that the rainfall processes in the two experiments are qualitatively similar but quantitatively different. Compared with the CTL experiment, P_S in the SNC experiment increased by 8.8%, which is mainly resulted from the difference in macroscopic and microscopic physical processes of precipitation between the two experiments. The different in Q_WVE is_{the most obvious with different SST.}

Abstract:Using the WRF model and NCEP reanalysis data, the authors numerically simulated a real Mei-yu rainstorm. Based on the high-resolution simulation results, the authors calculated the HKE (horizontal kinetic energy), VKE (vortex kinetic energy), and DKE (divergence kinetic energy) spectra, and determined the kinetic energy budget. The results show that in the development of the rainstorm, the mesoscale kinetic energy increases with height, with significant increases starting at the lower end of the mesoscale, which leads to the spectral transition characteristics in the mesoscale band. However, the transition scales vary at different heights. In the troposphere, the VKE is greater than the DKE, and in the tropospheric layer the opposite is the case. Different precipitation stages, different heights, and different scales have different sources of kinetic energy. In the upper troposphere, the contributors to mesoscale kinetic energy tend to be nonlinear and pressure terms. In the lower stratosphere, the effect of pressure is more obvious.

Abstract:To better understand the climate changes over China associated with a 1.5℃ global warming world relative to the pre-industrial levels, the authors present an analysis based on numerical experiments undertaken using 39 Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models. The results indicate that a global warming of 1.5℃ will occur in the median year 2034 for the representative concentration pathway (RCP) 2.6, 2033 for RCP4.5, and 2029 for RCP8.5. Under a 1.5℃ global warming world, annual and seasonal temperatures are projected to increase by an average of 1.8℃ and 1.6-2.1℃, respectively, with the strongest warming occurring in winter. Generally, the warming strengthens from south to north, and an amplification occurs in the Tibetan Plateau. Change signals of annual and seasonal temperatures exceed the local natural internal variability over the entire country, and the corresponding signal-to-noise ratios average 3.4 and 1.6-2.7, respectively. Annual and seasonal precipitation is expected to increase in northern China and decrease in southern China. Annual and seasonal precipitation averaged over the country increases by 1.4% and 0.1%-5.1%, respectively, with the greatest increase occurring in winter. On the whole, changes in annual and seasonal precipitation do not fall outside the local natural internal variability, and the signal-to-noise ratios averaged over the country are 0.1 and 0.01-0.2, respectively. Greater inter-model uncertainty occurs in the projection of changes in precipitation than that of changes in temperature, and the same holds for the seasonal projections.

Abstract:In this paper, an observational and diagnostic analysis of an extreme heavy precipitation (EHP) event in Beijing on 23 June, 2011 is performed. This analysis used radar-observed data and automated weather station observations with high time and space resolution, combined with NCEP 1°×1° reanalysis data and conventionally observed data. Results showed that the EHP event was attributable to the high precipitation supercell (HPS) at the right end of the squall line moving southeast, which occurred at the highest latitude recorded among all HPS events documented in China thus far. The HPS had distinctive V-shaped inflows in both in the right-front and right-rear flanks, which differed from those in the known HPS model. This indicated that the cold dry air flow at mid- and lower levels and the warm moist air flow at lower levels were significant. In terms of environmental conditions, there was an inversion layer (IL) in the lower levels of the troposphere, indicating that the thunderstorm would intensify explosively when the cap was broken. However, the IL formed within 6 hours from 0800 BT (Beijing time) to 1400 BT, which was difficult to forecast. Compared with other thermodynamic parameters, storm-relative helicity and bulk Richardson number sharply increased from 0800 BT to 1400 BT before the occurrence of the HPS, which had certain indicative effects. The westerly upper-level jet and low-level easterly wind were significant, which enhanced the vertical shear of horizontal wind over Beijing, facilitated the convective instability with the dry upper layer and moist lower layer, and formed the secondary circulation. Meanwhile, the upper-level jet caused obvious differential vertical advection of equivalent potential temperature, which maintained and strengthened the convective instability. Combined with the terrestrial effects, there existed both an obvious dry-moist boundary line and a wind convergence line near the 100 m topographic elevation line in western Beijing. The water vapor supply was mainly from the low-level easterly wind and local water vapor. When the squall line invaded Beijing from the northwest and moved to the southeast, in the northern mountainous areas, the thunderstorm did not develop significantly due to insufficient conditions. In contrast, in the western mountainous areas, supported by a lake, the urban heat island effect, low-level easterly winds, a cold pool outflow, and the other favorable environmental factors, the thunderstorm at the right end of the squall line strengthened significantly. Notably, it developed into the HPS when it reached the 100 m topographic elevation line, which, in turn, caused the rainstorm center at the Moshikou station of Shijingshan District.