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A deep learning based fusion precipitation nowcast method and its application study over East China
 doi: 10.11676/qxxb2023.20220081
[Abstract](0) [PDF 3808KB](0)
Research on frequency correction algorithm for spaceborne precipitation measurement radar and ground-based weather radar
 doi: 10.11676/qxxb2023.20220093
[Abstract](8) [PDF 428KB](5)
Comparative Analysis of Biweekly Oscillation Characteristics of Precipitation during Meiyu Period in the Yangtze Huaihe River basin in 2016 and 2020
 doi: 10.11676/qxxb2023.20220075
[Abstract](10) [PDF 23132KB](6)
The interactions between stratosphere and troposphere during the influence of blocking events in the extratropical northern hemisphere on cold air outbreaks in East Asia
 doi: 10.11676/qxxb2023.20220094
[Abstract](10) [PDF 5058KB](5)
Automatic radial velocity dealiasing algorithm for S-band Doppler weather radar
HAN Songyu, LIU Yongsheng, LUO Yang, YANG Ming, LUO Changrong
 doi: 10.11676/qxxb2022.059
[Abstract](112) [FullText HTML](14) [PDF 16055KB](16)
Radial velocity ambiguity limits the application of radar velocity data. To address the issues of the ambiguity of isolated echo or echo isolated by distance ambiguity and clutter interference as well as the problem in traditional method that takes radial straight line as initial reference in velocity dealiasing algorithm, a new automated Doppler radar velocity dealiasing algorithm is proposed. (1) Two zero velocity curves are obtained by finding the zero velocity junction point to roughly partition positive and negative velocity regions. After the positive and negative zoning, the clutter interference area and non clutter interference area are identified. For the clutter interference area, whether it meets multiple conditions with ambiguity characteristics is determined point by point. For the non clutter interference area, the ambiguity boundary is determined to delineate the ambiguity area block for dealiasing, which is conducted at the remaining points. (2) If the zero velocity curves cannot be determined, either the zero velocity curves information recorded in the upper layer is used or the qualified radial linear zero velocity line is searched. (3) If the zero speed line still cannot be determined, whether it meets multiple conditions with ambiguity characteristics will then be determined point by point. The algorithm is verified by using 3407 velocity ambiguity volume scan data of 11 cases such as squall lines, hails and strong typhoons observed by S-band radar, and the overall accuracy is higher than 98%. Using the zero velocity curves to determine the positive and negative zones, identifying the ambiguity area blocks and considering the extended neighborhood search in point by point judgment are conducive to the dealiasing processing of isolated echoes and echoes isolated by distance ambiguity. This method is more effective than the operational method. For the hail case that occurred on 4 March 2018, the accuracy is 10% higher than that by the operational method. Using the method of determining whether it meets multiple ambiguity feature conditions point by point for the clutter interference area, the ambiguity points can be successfully removed without being affected by the clutter. Comprehensive consideration of the upper zero velocity line and relevant information in the image that is helpful to determine the zero velocity curves and strict examination and test can ensure the accuracy of the zero velocity curve, which is conducive to the successful processing of velocity dealiasing.
Analysis of the monitoring ability of high-resolution satellites for the "7·20" heavy rain in Henan
LIU Songnan, WANG Jun, WANG Huijun
 doi: 10.11676/qxxb2022.053
[Abstract](93) [FullText HTML](16) [PDF 3557KB](39)
On 20 July 2021, an abrupt rainstorm occurred in central and northern Henan province, China and killed at least 302 people. Such kind of extreme precipitation events have great impacts on social and economic development and human lives. Therefore, accurate monitoring of such rainstorm events is crucial. Qualitative and quantitative methods are used to comprehensively evaluate 10 high-resolution satellite precipitation products (CMORPH-Raw, CMORPH-RT, PERSIANN-CCS, GPM IMERG-Early, GPM IMERG-Late, GSMaP-Now, GSMaP-NRT, FY-2F, FY-2G and FY-2H) of this extreme rainstorm event, and the ability of these 10 products to represent different levels of precipitation are also analyzed. The results show that these 10 satellite precipitation products can capture spatial distribution characteristics of the rainstorm that is located in central and northern Henan, but all satellite precipitation products underestimate the precipitation value at the rainstorm center. As the precipitation level increases, the hit rate and the TS score decrease, and the false alarm rate increases. CMORPH-RT has a better ability to capture the rainstorm than CMORPH-Raw, and shows the ability to capture rainstorm process. GPM IMERG-Late is more accurate than GPM IMERG-Early. Compared to GSMAP-Now, the performance of GSMAP-NRT enhances. PERSIANN-CCS and FY-2F show a poor performance and cannot capture this extreme rainstorm event. Among them, CMORPH-RT has the best performance, since it accurately captures the rainstorm center and magnitude that are the closest to observations. In general, satellite precipitation products that integrate infrared and passive microwave information are better than the products that only use infrared information. The satellite precipitation retrieval algorithm and the amount of passive microwave data have a great impact on the accuracy of satellite precipitation products.
Variation characteristics of clouds and their relationship with precipitation over China in El Niño decaying summers
PENG Yanyu, LIU Yu, GAO Qianqian
 doi: 10.11676/qxxb2022.049
[Abstract](94) [FullText HTML](21) [PDF 46604KB](23)
Based on various datasets, including observations of ground stations and satellites in China from 1961 to 2010, the variation characteristics of clouds and different types of precipitation over China were analysed in the decaying summers of two types of El Niño events (eastern Pacific El Niño and central Pacific El Niño), and the complex relationship between the variation characteristics of clouds and total precipitation anomalies was discussed. The results demonstrate that the anomalies of total cloud amount and low cloud amount in El Niño decaying summers are about the same as those of precipitation based on station observations. Low cloud forms such as cumulonimbus, nimbostratus, and stratocumulus have become more common. A significant positive correlation exists between cloud amount anomalies and precipitation anomalies over China. At stations where the positive correlation passes the significance test, the linear relationship between cloud amount anomalies and precipitation anomalies is clear and also passes the significance test. In the meantime, the growing ratios of total cloud amount and low cloud amount to precipitation are close to 1:3 and 1:1, respectively. Variations in cloud amounts of high cloud and deep convective cloud, cloud optical thickness and cloud water path are positively correlated with precipitation anomalies based on station records. Convective precipitation anomalies, which account for up to 80% of total precipitation in the regions south of the Yellow River, are the major cause of fluctuation in total precipitation. Low clouds are a good predictor of precipitation in eastern China. The fluctuation of convective precipitation is primarily responsible for the anomalies of total precipitation in southern China in El Niño decaying summers, and the abnormal increases in convective precipitation are directly associated with anomalous increases in deep convective clouds. An El Niño event can boost convective activities in China's monsoon zone in the subsequent summer. Specifically, it leads to increases in deep convective cloud amount and thickness of cloud layer and promotes upward development of cloud top. These effects eventually increase convective precipitation and result in the formation of abnormal rain band.
Analysis of a backflow heavy snowfall event in central North China using multi-source data
QIAN Weimiao, LUO Yali, CAO Yue, ZHANG Xiao, CHE Shaojing
 doi: 10.11676/qxxb2022.052
[Abstract](76) [FullText HTML](17) [PDF 5493KB](33)
A backflow heavy snowfall event occurred in central North China from 07:00 BT 5 January to 04:00 BT 6 January 2020, producing a maximum snowfall of 15.5 mm. The ERA5 reanalysis and high-resolution observation data from multiple sources are utilized to analyze synoptic background and local dynamic and thermal conditions of this event as well as the spatiotemporal distribution and microphysical features of snowfall. The results show that 7 h prior to the snowfall, northeasterlies below 900 hPa (called 'backflow') swept the northeast plain of China and the Bohai Sea and reached the North China Plain, under the joint influence of an inverted trough over the Yellow River bend and a high pressure in the Northeast plain. A shallow near-surface mesoscale convergence line formed in the North China Plain under the blocking effect of Taihang mountain. The convergence line corresponds to the heavy snowfall area. At 850 hPa, southeasterly flows around the Southwest Vortex prevailed over the snowstorm area. Northeasterly winds below 800 m were observed in Shijiazhuang about 1 h before the snowfall, and temperature below 1 km height dropped rapidly to −5—−1℃, forming a 'cold pad'. An Low-Level Jet (LLJ) near 700 hPa over the heavy snowfall area appeared 2 h prior to the snowfall, and the LLJ became thicker and extended down to 2 km. The warm and moist air below the LLJ was forced to climb along the "cold pad", triggering snowfall. The maximum wind speed of LLJ (19 m/s) and the peak value of LLJ index (about 8) coincide with occurrence of the heavy snowfall greater than 1 mm/h. At the same time, the maximum center of ascending motion and water vapor transport is located near 700 hPa. Snow particles are 0.35—0.55 mm in diameter. There is a positive linear correlation between snow intensity and particle number concentration. The snow-producing cloud layer is located at 1.3—5.5 km height. The lower layer (below 3 km; about −10℃) is ice-snow mixing layer and the upper layer (3—5.5 km) is ice-snow layer. Relative humidity in the ice-snow layer is positively correlated with snow particle concentration and snowfall intensity. The fitting relationship between ground reflectivity factor (Z) and snowfall intensity (R) detected by disdrometer is Z=149.85×R1.14. These results provide a reference for better forecasting of heavy snowfall in North China.
Progress and challenges of deep learning techniques in intelligent grid weather forecasting
YANG Xuan, DAI Kan, ZHU Yuejian
 doi: 10.11676/qxxb2022.051
[Abstract](170) [FullText HTML](44) [PDF 589KB](72)
0—30 d seamless fine gridded weather forecasts have been initially established to cover fundamental forecast elements in China. In recent years, the advances and applications of deep learning have brought unprecedented changes to different fields. The capabilities of nonlinear mapping, massive information extraction, spatial-temporal modeling and other advantages of deep learning provide new concepts and methods for further improvement of forecast accuracy and refinement. The growing studies on deep learning techniques have been applied widely to weather forecasting, including statistical postprocessing, ensemble forecasting, analog ensemble, statistical downscaling, data-driven forecasting models and extreme weather forecasting. The deep learning techniques have demonstrated a great application potential. However, the application of deep learning in gridded weather forecasting is still at the initial stage. The challenges include algorithm selection, benchmark dataset, multi-source data blending, interpretability, reliability, availability and operational implementation, etc. when introducing it into current Intelligent Grid Forecast System. Review of the progress and challenges of the deep learning at fine gridded weather forecasting in recent years will be helpful for us to better understand deep learning techniques and their application in weather forecasting.
Assimilation of GCOM-W AMSR2 radiance data in CMA_GFS 4DVar
XIAO Hongyi, HAN Wei, BAI Yihong
 doi: 10.11676/qxxb2022.058
[Abstract](81) [FullText HTML](30) [PDF 12187KB](13)
The radiance data of satellite microwave radiometers play a more and more important role in the assimilation of numerical prediction systems due to the all-sky advantage of satellite observations and the all-weather availability of microwave soundings. As an important category of passive microwave radiometer, the application potential of microwave imager in numerical weather forecasting needs further verification and more sufficient exploration. Focusing on the Advanced Microwave Scanning Radiometer 2 (AMSR2) carried on the Global Change Observation Mission–Water (GCOM-W), the thinning scheme within 200 km radius is applied; a quality control scheme including nine issues of checks is developed to screen those contaminations including the sun-glint phenomenon and radio-frequency interferences which can disturb the low-frequency channels; a bias correction scheme on the basis of conventional predictors is employed to effectively reduce systematic deviations of instrument; the difficulty related to observation error evaluation is overcome by posteriori verification. Ten channels of GCOM-W AMSR2 are directly assimilated into the Global/Regional Assimilation and Prediction System–Global Forecast System (CMA_GFS, i.e., the GRAPES_GFS) version 3.0 by the four-dimensional variational (4DVar) assimilation method independently developed by the Numerical Weather Prediction Center of China Meteorological Administrator. A pair of batch experiments for one month indicates that, with the GCOM-W AMSR2 assimilation, the depiction of humidity analysis field is improved, the medium forecasting skills of various precipitation are also improved, and the prediction score card shows obvious positive impacts on the southern hemisphere and the equatorial region. Thus, direct assimilation of the GCOM-W AMSR2 into the CMA_GFS 4DVar is confirmed to be useful for improving the amount of observations in poor-data regions, and it can take advantage of the water vapor sensitivity to promote the skills of humidity analysis and precipitation prediction.
Haze Detction by multi-spectral channels of FY-3/MERSI
 doi: 10.11676/qxxb2023.20220079
[Abstract](23) [PDF 3672KB](5)
SUN Yuting, ZHENG Xiangdong, BIAN Jianchun, ZHANG Jinqiang, BAI Zhixuan
 doi: 10.11676/qxxb2022.054
[Abstract](79) [FullText HTML](9) [PDF 17210KB](17)
Tropospheric ozone (O3) has significance impacts on climate and air quality, yet observations of tropospheric O3 is not sufficient. In this study, vertical distribution of tropospheric O3 and associated meteorological processes from 25, July to 22 of August 2016 observed at Golmud, a city in Qinghai Province on the Northern Tibet Plateau (TP), is analyzed to better understand characteristics and mechanism of tropospheric O3 variation there. One general feature is that high (low) O3 corresponds to low (high) water vapor and high (low) potential vorticity. Except for the tropospheric O3 enhancement associated with the passage of a low-pressure trough from 25 to 27 July, the impacts of a warm blocking high and the passage of a deep convective system from the main area of the TP on the distribution of tropospheric O3 are observed and analyzed for the first time in the northern TP. After the formation of the blocking warm high to the northeast of the observation site, easterly winds maintain in the whole troposphere at Golmud from 31 July to 8 August, but tropospheric O3 concentration is only slightly higher on 2 August due to the anticyclonic shear along the northeast-southwest direction. Pollutant air mass with high O3 and specific humidity (q) below 6 km appear due to westward transport. The lowest O3 and the highest q during the entire observational period appear at the height above 10 km from 12 to 14 August with the passage of a deep convective system. Compared with the historical tropospheric O3 observed in Xining (from July to early August 1996), O3 at Golmud exhibits a seasonal low value in August, which is consistent with seasonal influences of the summer monsoon. Compared with historical tropospheric O3 observations in Linzhi (2014 July), Naqu (from late July to mid-August 2011) and Lhasa (August 1998), it is found that latitude has certain influences on O3 over the Tibetan Plateau.
Characteristics of dual-polarization structure and raindrop size distribution measured by a ground-based disdrometer of a squall line in Shandong
 doi: 10.11676/qxxb2023.20220070
[Abstract](27) [PDF 975KB](11)
Analysis of extreme convective winds caused by two different types of storms in a severe convective process
 doi: 10.11676/qxxb2023.20220050
[Abstract](38) [PDF 3667KB](21)
Joint effects of sea surface temperature over north Atlantic and tropical Indian Ocean on the interdecadal variation in Songhua River Basin warm season precipitation
 doi: 10.11676/qxxb2023.20220068
[Abstract](23) [PDF 2492KB](4)
A numerical study for climatic effects of irrigation in the Fergana basin,Central Asia
ZHANG Xuezhen, LIU Xinrui, YAN Jianwu, DING Nana
 doi: 10.11676/qxxb2022.056
[Abstract](80) [FullText HTML](16) [PDF 10618KB](8)
Central Asia is located in the arid climate zone and agricultural production is highly dependent on irrigation. However, the effects of irrigation on local climate remain unclear. The effects of irrigation on warm season (May-September) climate in the Fergana basin are studied using the Weather Research and Forecast model (WRF), in which an irrigation parameterization scheme is implemented and soil data are also updated. A pair of simulations, i.e., the IRRG that includes irrigation and the NATU that excludes irrigation, are carried out for the years of above normal rainfall (i.e. 2009), below normal rainfall (i.e. 2008) and normal rainfall year (i.e. 2007), respectively. The climatic effects of irrigation are then studied by comparing the IRRG and NATU simulations. The results are as follows. (1) Irrigation leads to an average increase in surface latent heat flux (79.2 W/m2) and an average decrease in surface sensible heat flux (−61.3 W/m2). As a result, daily mean temperature cools by 1.7℃ and specific humidity increases by 2 g/kg (accounting for about 36% of NATU) in the warm season. Since May to June is rainy season and July to August is dry season, the irrigation demand from July to August is larger than that from May to June. Thereby, the cooling and wetting effects of irrigation are also larger from July to August. (2) The cooling and wetting effects mainly exist in the irrigation area with cooling of 2℃ and specific humidity increment of 2.4 g/kg, while they are too weak to be detected beyond the irrigation area. Meanwhile, from the ground to the upper atmosphere, the cooling and wetting effects gradually weaken and cannot be detected above the pressure level of 500 hPa (about 4000 m above the ground). (3) In the central plain of the basin, the potential rainy effect caused by air humidity increment and the potential rainless effect caused by convective inhibition offset each other. As a result, local precipitation shows no detectable differences between the IRRG and NATU simulations. However, irrigation lead to precipitation increment (~0.6 mm/d) in remote areas over the northern and southern mountains surrounding the basin. (4) Differences in irrigation demand and their effects on local climate under different climate backgrounds mainly exist in May to June. The irrigation demand in 2008 is more than that in 2009 by 20 mm per month. Consequently, the cooling effect is stronger by 0.3℃ and the wetting effect is stronger by 0.5 g/kg in 2008 than those in 2009. Meanwhile, the rainy effect is weaker in 2008 than that in 2009 by 0.6 mm/d.
Interdecadal variation of land precipitation in China and relative contributions of global warming,IPO and AMO
DU Jiayu, TAO Li, XU Chengyu
 doi: 10.11676/qxxb2022.055
[Abstract](64) [FullText HTML](24) [PDF 8486KB](20)
Although land precipitation across China is dominated by inter-annual variability, we identify the areas of significant variability of decadal (10—20 a), multidecadal (20—50 a) and secular trend (>50 a) by applying singular spectrum analysis (SSA). In addition, relative contributions of different SST modes to the trend and (inter) decadal variability of precipitation over China during JJA/DJF of 1934—2018 are investigated by singular value decomposition (SVD) and multiple linear regression methods. Based on SVD analysis of precipitation in China and SST in the middle and low latitudes, it is found that global warming (GW) is the primary SST mode affecting precipitation in China in both winter and summer. The Interdecadal Pacific Oscillation (IPO) plays a second role. A multivariate linear regression model is then applied to quantitatively evaluate the variance contributions and relative contributions of GW, IPO and Atlantic Multidecadal Oscillation (AMO) to precipitation in different regions of China. The results show that GW, IPO and AMO can explain about 30% of the trend and (inter) decadal precipitation in Northwest China and North China in summer, and the relative contribution of GW is the largest, followed by that of IPO. In winter, the above three factors can explain 42% of the trend and (inter) decadal precipitation in Northeast China and about 30% in Northwest China and North China. In Northeast China and Northwest China, the relative contribution of GW is dominant, and the contribution of AMO is second to that of GW. In North China, GW contribution is also dominant, followed by that of IPO.
Winter cold front activities and associated circulation characteristics in North China in the recent 30 years detected by an automatic identification method
QIN Yujing, FENG Mengru, LU Chuhan, HE Shuya, LI Liping, HU Chunli
 doi: 10.11676/qxxb2022.057
[Abstract](48) [FullText HTML](8) [PDF 5172KB](12)
In this study, the dataset of winter cold front activities in Eurasia is obtained by applying the two-step cold front identification method to the ERA5 reanalysis data for the period from 1989 to 2018. Moreover, the characteristics of winter cold front activities in North China in the recent 30 years are analyzed, and possible mechanisms for cold front activity anomalies are discussed. The results show that North China is the key area with the highest frequency of cold fronts in the East Asian continent. The frequency index of cold front activities in North China has an obvious interannual variation. In the years of strong cold front activities in North China, the Eurasia teleconnection pattern from North Atlantic to Eurasia is obviously in positive phase, and negative geopotential height anomalies appear at 500 hPa over North China. It indicates an enhancement of the East Asian trough and a stronger Siberian High in surface. When anomalously warm advection prevails over the ocean in the northern margin of Eurasia, cold air activities and the frequency of cold fronts both increase in North China. The SST anomalies in the northern Atlantic Ocean may trigger Rossby waves in the middle and upper troposphere, which propagate eastward and reach North China via Europe and western Siberia, affecting the frequency of cold fronts in North China.
Impacts of AMO on the interdecadal variability of South China Sea summer monsoon withdrawal and associated mechanisms
SONG Chengyu, WANG Jing, LIU Yanju, LI Qiaoping, DING Yihui, SHEN Xinyong
 doi: 10.11676/qxxb2022.050
[Abstract](85) [FullText HTML](14) [PDF 3624KB](31)
The present study investigates the interdecadal variability characteristics of South China Sea summer monsoon withdrawal (SCSSMW) and impact of the North Atlantic Multidecadal Oscillation (AMO) on it based on the NOAA-CIRES 20th Reanalysis data reconstructed by the Physical Sciences Laboratory (PSL) of the National Oceanic and Atmospheric Administration (NOAA) and the Cooperative Institute for Research in Environmental Sciences (CIRES), the Extended Reconstructed Sea Surface Temperature (ERSST) dataset from the International Comprehensive Ocean Atmosphere Data Set (ICOADS). Numerical experiments are also implemented. The results show that the timing of SCSSMW has obvious interdecadal variability. During the late (early) years of SCSSMW, there are significant cyclonic (anticyclonic) circulation anomalies and more (less) convective precipitation over the South China Sea and its nearby areas. Further studies show that there is a significant positive correlation between AMO and the interdecadal variability of SCSSMW. In other words, when AMO is in the positive phase, SCSSMW is later. When AMO is in the negative phase, SCSSMW is earlier. The warming SST over the North Atlantic (i.e., AMO in the positive phase) releases more heat flux from the ocean to the atmosphere, leading to significant increase of convective activity in the troposphere over the North Atlantic, which can then trigger abnormal wave activities over the North Atlantic through sea-air interaction and enhanced convective activity. And this further affects the formation and propagation of the mid-latitude Eurasian teleconnection wave train that is closely related to the variation of atmospheric circulation over the key area of Northeast Asia, causing positive geopotential height anomaly and obvious descending motion throughout the troposphere over the key area of Northeast Asia and producing divergent motion in the lower troposphere. The energy is transferred to the South China Sea and its adjacent areas with the divergent wind flow and produces convergence and upward motion. The cyclonic circulation anomaly over the South China Sea further enhances, leading to later SCSSMW. Roughly opposite mechanism works during the negative phase of AMO, leading to earlier SCSSMW.
Analysis of an extreme flash rain event under the background of Subtropical High based on dual-polarization phased array radar observations
PAN Jiawen, PENG Jie, WEI Ming, ZHENG Xiuyun, WU Weijie, Gao Shan, WU Juxiu, Cai Jing
 doi: 10.11676/qxxb2022.060
[Abstract](228) [FullText HTML](20) [PDF 18942KB](132)
An extreme flash rain event that occurred in Xiamen under the background of Subtropical High on August 11 2021 is analyzed based on X-band dual-polarization phased array radar observations. Dynamic and microphysical characteristics of the precipitation system are analyzed using the Doppler radar wind field retrieval technique combined with high-precision topographic data. The study yields the following results. (1) The event took place under the control of the Subtropical High with the characteristics of weak synoptic-scale forcing. The surface wind convergence line promoted the formation of a quasi-linear convective system (QLCS), and the back-building process of the QLCS led to local extreme precipitation event. (2) The updraft lifted the raindrops to the mid-level, forming a large particle accumulation layer. When it descended, the rain intensified. The configuration of inclined updraft and downdraft ensured that the falling of large particles would not suppress updraft, which is favorable for the development and maintenance of convective system. The downdraft triggered the development of the upstream convective system, forming a back-building process. (3) The impact of local terrain on the precipitation system was highlighted under the weak synoptic scale background. The low-level convergence induced by local terrain caused the polarization parameters such as differential reflectivity (ZDR) and specific differential phase (KDP) to increase significantly on the windward slope, and the large value area was maintained there. The larger, denser precipitation particles produced extremely high precipitation efficiency. (4) The warm rain process and the ice phase process coexisted in this extreme precipitation event. The warm rain process played a major role in the formation of rain, and the melting of ice particles accelerated this process. (5) At high rain rate, the breakage and collision of raindrops tend to balance, and the increase of rain rate depends on the increase of raindrop concentration. Therefore, ZDR can be used to determine whether the rain rate is increasing. (6) The evolution of the ZDR and KDP column is an appropriate index that can reflect the development of the surface rain rate. During a continuous precipitation process, the re-development of the ZDR (KDP) column height occurs earlier than that of the precipitation system.
Application Research of Merging GNSS/PWV and FY-4A/GIIRS Water Vapor Profile
 doi: 10.11676/qxxb2022.070
[Abstract](39) [PDF 2959KB](14)
Influence of Boreal Summer Intraseasonal Oscillation’s Interdecadal Variation on the Abrupt Decrease of Multiple Tropical Cyclones in western North Pacific
 doi: 10.11676/qxxb2023.20220044
[Abstract](31) [PDF 1353KB](7)
Analysis on the development and maintenance mechanism of extreme heavy rainfall in Henan on 20 July 2021
 doi: 10.11676/qxxb2023.20220014
[Abstract](68) [PDF 4585KB](22)
Analysis of a damaging wind case caused by bow echo in the environment of cold vortex over North China Plane
 doi: 10.11676/qxxb2023.20220024
[Abstract](324) [PDF 3974KB](46)
Study on the model uncertainty of rainstorm forecast in Guangzhou on 7 May 2017
 doi: 10.11676/qxxb2023.20220047
[Abstract](44) [PDF 2863KB](16)
The dynamical-statistical extended-range prediction of precipitation and its extreme event over southern China
 doi: 10.11676/qxxb2023.20220061
[Abstract](44) [PDF 2488KB](10)
The ambient field characteristics for quasi-straight long path and multi-turning path of eastward moving Tibetan Plateau Vortex Yu Shuhua1,2 Gao Wenliang1,2,3 Peng Jun1,2
 doi: 10.11676/qxxb2022.067
[Abstract](22) [PDF 4792KB](4)
Evaluation of forecast skills and error correction of S2S models for pentad precipitation anomaly in Sichuan Province during rainy season
 doi: 10.11676/qxxb2022.068
[Abstract](30) [PDF 3316KB](10)
Assessment and Merged Optimization of Multi-Source Precipitation Products over Northern China in Winter
 doi: 10.11676/qxxb2022.069
[Abstract](35) [PDF 3171KB](8)
Machine learning-based affecting factors analysis and estimation of winter temperature anomalies in China
 doi: 10.11676/qxxb2023.20220078
[Abstract](63) [PDF 1456KB](10)
Improved interannual predictability of winter North Atlantic Oscillation with a weakly coupled data assimilation scheme
 doi: 10.11676/qxxb2023.20220062
[Abstract](22) [PDF 2725KB](3)
Multidecadal variability of sea ice in the East Siberia-Beaufort Sea region and its linkage with the Atlantic Multidecadal Oscillation
 doi: 10.11676/qxxb2023.20220080
[Abstract](40) [PDF 2151KB](10)
Research on objective forecast algorithm of 100-meter gust based on gust coefficient model
 doi: 10.11676/qxxb2023.20220052
[Abstract](50) [PDF 3594KB](13)
 doi: 10.11676/qxxb2023.20220023
[Abstract](102) [PDF 4708KB](31)
Differences in Spatiotemporal Variation and Risk Zoning of Four Types of Extreme Cold Events in Jiangsu Province
 doi: 10.11676/qxxb2023.20220058
[Abstract](34) [PDF 1787KB](12)
Winter Olympic comprehensive meteorological observation platform of Haituo Mountain and the research progress
 doi: 10.11676/qxxb2023.20220029
[Abstract](51) [PDF 11758KB](21)
Relationship between aerosol pollution and different precipitation types in autumn and winter in North China
 doi: 10.11676/qxxb2022.066
[Abstract](44) [PDF 1570KB](14)
Raindrop Spectral Characteristics and Z-R Relationship of Different Types of Rainstorm in Huaibei Region
 doi: 10.11676/qxxb2022.025
[Abstract](56) [PDF 1346KB](16)
Improvement of the three-dimensional stochastic cloud-to-ground lightning model and numerical simulation of multiple upward leaders
 doi: 10.11676/qxxb2022.065
[Abstract](26) [PDF 889KB](2)
Analysis on the asymmetric characteristics and causes of the wind circle radius of tropical cyclones
 doi: 10.11676/qxxb2022.064
[Abstract](36) [PDF 2752KB](6)
Review of Advances in Hail Formation Process and Hail Suppression Research
 doi: 10.11676/qxxb2022.061
[Abstract](79) [PDF 4630KB](25)
A Case Study on the Radar Characteristics and Physical Process Involved in the Genesis of a mini supercell Tornado under the background of cold vortex
 doi: 10.11676/qxxb2022.063
[Abstract](97) [PDF 3361KB](25)
Climatic characteristics and influencing factors of regional extremely dense fog in Anhui province
 doi: 10.11676/qxxb2022.062
[Abstract](43) [PDF 2903KB](19)
2022year No.4
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Based on the Rutgers University Global Snow Lab snow cover, the British Meteorological Office Hadley Center sea surface temperature (SST), soil moisture of the European Centre for Medium-Range Weather Forecasts Fifth Generation Reanalysis (ERA-5), the National Centers for Environmental Prediction National Center for Atmospheric Research reanalysis, the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center Merged analysis of Precipitation (CMAP) and the Global Precipitation Climatology Project (GPCP) precipitation, effects of the Tibetan Plateau (TP) snow and El Niño-Southern Oscillation (ENSO) as preceding signals on the South China Sea (SCS) summer monsoon and precipitation are analyzed using methods of correlation analysis, composite analysis and regression analysis. Results indicate that the SCS summer monsoon is associated with both the TP snow and ENSO on the interannual scale. When the TP snow is higher in the west and lower in the east in spring, the tropospheric temperature in the west of the TP is abnormally low in the subsequent summer, which generates downdrafts over the plateau that flow outward. Accordingly, there are also descending airflows over the South China Sea in the lower and middle troposphere. In addition, anomalously high SSTs in the east-central equatorial Pacific may cause positive SST and tropospheric temperature anomalies in the Indian Ocean with northeasterly wind anomalies over the Northwest Pacific Ocean, which further strengthens the anticyclonic circulation anomaly over the South China Sea. When the TP snow and ENSO are synergistic, their influences on the SCS summer monsoon are stronger. Their joint effect further strengthens the lower-tropospheric anticyclonic anomaly over the South China Sea in summer, weakens the SCS summer monsoon and decreases precipitation in the South China Sea.
The influences of active days of the Madden-Julian oscillation (MJO) over the Indian Ocean on summer precipitation days over the middle and lower reaches of the Yangtze River were investigated. Daily precipitation data collected at 753 stations, monthly sea surface temperature (SST) data from the Hadley Centre, daily mean reanalysis data from the National Centers for the Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), and all-season real-time multivariate Madden-Julian Oscillation (RMM) index during 1980—2020 were used. The results show that the active days of MJO over the Indian Ocean have a statistically significant relationship with precipitation days over the middle and lower reaches of the Yangtze River, especially with the heavy precipitation days, since the MJO related circulation anomalies can continuously transport water vapor to eastern China. Further research indicates that the relationship between active days of MJO over the Indian Ocean and the precipitation days over the middle and lower reaches of the Yangtze River has experienced a decadal change with their relationship being significant since the 2000s. The decadal change of this relationship might be attributed to decreased variability in SST in the Indian Ocean. This decreased interannual variability of SST suggests weakened modulation effects on precipitation over the middle and lower reaches of the Yangtze River by the tropical Indian Ocean. In contrast, the MJO effects on the precipitation days over the middle and lower reaches of the Yangtze River turn to be significant after the 2000s due to less disturbances from the Indian Ocean SST.
Climate model reolution, as one of the important factors affecting model simulation results, are not fully understood in terms of their effects on aerosol-cloud interactions. In this study, the Community Atmosphere Model Version 5.3 is run at three horizontal resolutions (2°, 1°, 0.5°) under the 2000 and 1850 aerosol emission scenarios, respectively, to test whether increasing the resolution can improve the simulation capability of climate models, analyze the similarities and differences of aerosol climate effects at different resolutions, and explore the influence of model resolution on the numerical results of aerosol climate effects. The comparison between observations and model results shows that increasing the resolution can significantly improve the model's ability to simulate total cloud cover and cloud shortwave radiative forcing, and the simulation results are closer to observations at 0.5° resolution, while other variables are not significantly improved. The global average aerosol climate effect is more consistent at different resolutions, with an increase in total cloud cover, cloud water liquid path, and enhanced cloud shortwave and longwave radiative forcing, while the cloud droplet effective radius at the top of cloud, surface air temperature and precipitation are reduced. At different resolutions, the zonal mean tendencies of the changes in aerosol optical thickness, cloud water liquid path, surface air temperature, cloud shortwave and longwave radiative forcing caused by the increase in aerosol is similar, but there are differences in magnitude. Furthermore, the variation of precipitation and cloud cover are quite different in the zonal mean tendencies and values, which still have large uncertainties on regional scale. On the global, the annual average of aerosol indirect radiative forcing (AIF) at 0.5° resolution is reduced by 2.5% compared to the results at 1° resolution and by 6.4% compared to the results at 2° resolution. Overall increasing the model resolution can partially improve the model simulation capability but weakens AIF. However, the variation of aerosol-induced clouds and precipitation varies greatly at different resolutions, and there is a large uncertainty.
In order to study the simulation effects of different land surface models on soil temperature in China, the Noah and Noah-MP land surface models are driven by the atmospheric driving data of the China Meteorological Administration (CMA) land surface data assimilation system (CLDAS) to simulate soil temperature in China. Soil temperature simulations of GLDAS_Noah, CLDAS_Noah and CLDAS_Noah-MP are evaluated from the perspectives of spatial distribution, different seasons, time series in different regions, etc. based on soil temperature observations collected at 2380 sites during 2010—2018 in China and the Noah soil temperature from the United States Global Land Data Assimilation System (GLDAS_Noah). This study realizes the comparative analysis of soil temperature simulated with different driving data, with same land surface models and same driving data, and with different land surface models. The results show that the GLDAS_Noah, CLDAS_Noah and CLDAS_Noah-MP can reasonably simulate spatial distributions of soil temperature at 10 and 40 cm-depth in China from a qualitative point of view, but there are certain differences in magnitude, which mainly occur in snow-covered areas of Northeast China, Xinjiang and Qinghai-Tibet Plateau. From a quantitative perspective, with the same land surface model and different driving data, CLDAS_Noah is better than GLDAS_Noah in different seasonal assessments based on bias spatial distributions and RMSE (Root Mean Square Error) time series in different regions. This result can indirectly show that CLDAS atmospheric driving data is better than GLDAS Atmospheric driving data and the atmospheric driving data is one of the important factors to improve the accuracy of soil temperature simulation. With the same driving data and different land surface models, the overall effect of CLDAS_Noah-MP is better than that of CLDAS_Noah. Among them, the errors of CLDAS_Noah winter soil temperature at 10 and 40 cm depths in snow-covered areas are significantly greater than that of CLDAS_Noah-MP, which may be related to the improvement of Noah-MP parameterization scheme in snow-covered areas. However, the spring soil temperature simulation errors of CLDAS_Noah-MP at 10 and 40 cm depths in Northeast, North China, and Qinghai-Tibet Plateau are significantly larger than that of CLDAS_Noah, which may be related to the snow melting parameterization scheme in the model. In short, this research provides certain references for subsequent development of soil temperature multi-model integration research and in-situ soil temperature data assimilation research and the final development of high-quality soil temperature dataset in China.

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Supervisor: China Meterological Administration

Sponsor: China Meteorological Society



Editor In Chief: Yihui DING