Table of Content

28 October 2023, Volume 39 Issue 5 Previous Issue    Next Issue

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Analysis of the causes of complex path and heavy rain of typhoon "LUPIT"(No.2109) Hui LIN,Jingjing CHENG,Yibin ZHUANG,Yidan HUANG,Jinpeng CHEN,Xiaoxiang HONG,De'nan YANG 2023, 39 (5):  1-8.  doi: 10.3969/j.issn.1673-503X.2023.05.001 Abstract ( 128 )   HTML ( 19 )   PDF (6632KB) ( 212 )   Save Using the data of encrypted automatic meteorological observation station, typhoon real track data, NECP reanalysis data, and FY-4A satellite TBB data, the causes of the complex path and heavy rain of typhoon "LUPIT" (No.2109) were comprehensively analyzed.The results show that the strong subtropical high in late July and the strong monsoon convergence zone along the coast of South China provide good energy and water vapor conditions for the offshore generation and development of typhoons.The slow movement of the typhoon, the strengthening of the upturning cooling effect of the seawater, the increase of vertical wind shear in the environment, and the weakening of the divergence conditions in the upper level make it impossible for typhoon "LUPIT" to strengthen rapidly offshore.The subtropical high ridge line of tropical high-pressure retreats rapidly to the south, and the change of deep guiding airflow and the interaction of the two typhoons make "LUPIT" appear an unusual "S" path.Water vapor transported by the southwest monsoon, the strong influence of low-level jets, the typhoon′s inverted trough, and the asymmetry of the typhoon′s structure are the main reasons for the uneven distribution of heavy rain and falling areas in Zhangzhou. Figures and Tables | References | Related Articles | Metrics

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Characteristic analysis of thunderstorm gale process in Shenyang under a background of cold vortex Pengyu HU,Shuang XU,Shibo GENG,Chuanlei CHEN,Chang SU,Shengyuan CHEN 2023, 39 (5):  9-18.  doi: 10.3969/j.issn.1673-503X.2023.05.002 Abstract ( 156 )   HTML ( 35 )   PDF (8027KB) ( 228 )   Save Based on the data of precipitation observation at Liaoning national station and regional automatic station, doppler weather radar, wind profile radar, and hourly reanalysis data of the ECMWF ERA5, the formation mechanism of extreme disaster-causing thunderstorms and gales in Shenyang from the evening to the night of June 25, 2022, and the prediction effect of the numerical model were analyzed.The results show that the extreme hailstorm occurs under the background of the northeast cold vortex, the shear line, and the ground convergence line jointly trigger the generation of convective storms, and the strong vertical wind shear and unstable stratification enhance the development of hailstorms.In the process of the strong hailstorm, several strong convective cells gradually develop and appear as bow echoes after consolidation and enhancement.The existence of shallow low-level gamma mesoscale vortices in the front of the bow echo can lead to the enhancement of downdraft, and the combination with the backward inflow jet can lead to local extreme wind.The mesoscale numerical model can predict the circulation situation and precipitation area of severe convective weather to a certain extent, but the prediction of the intensity of the convective storm is still difficult. Figures and Tables | References | Related Articles | Metrics

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Analysis of a thunderstorm gale process formed by the collision of sea breeze front and gust front in the northern Liaodong Bay Chao JIANG,Kuizhi CAI,Lei YANG,Shiteng CAO,Yu CHEN,Yiwen WANG,Weilong BAN 2023, 39 (5):  19-27.  doi: 10.3969/j.issn.1673-503X.2023.05.003 Abstract ( 162 )   HTML ( 16 )   PDF (7621KB) ( 119 )   Save Based on the dual polarization Doppler weather radar high altitude observation data, encrypted automatic station data, and ERA5 reanalysis data in Yingkou of Liaoning province, a thunderstorm gale process formed by the collision of sea breeze front and gust front in the northern Liaodong Bay on May 28, 2021, was analyzed.The results show that the mesoscale sub-cold front moves southward and forms a surface convergence line that confronts the northerly wind and the southwest sea breeze, which triggers strong convection in conjunction with dryline.Before the collision between the sea breeze front and the gust front, the echo centroid of the individual in the mature stage of the upstream sinks, and the sinking outflow promotes the rapid development and enhancement of the downstream monomer.The cold pool density current plays a key role in triggering and enhancing the downstream cumulus convection.The surface temperature is increased by the daytime clear sky radiation warming, which is conducive to the accumulation of convective effective potential energy.The unstable stratification and strong vertical wind shear in the Panjin region lead to the continuous development and strengthening of the southern pressure of the convective system.A conceptual model of thunderstorms generated by the frontal collision of the sea breeze front and gust front in this area is initially established.The northern sea breeze front collides with the gust front generated by southward convection in Liaodong Bay, and the air climbs northward along the gust front.Under the influence of the northward guiding flow, the northward moving component of the convective system is canceled out, and the southward convective system continues to develop under better environmental conditions.This will maintain the strength of the convection and affect the downstream areas of thunderstorms and gales. Figures and Tables | References | Related Articles | Metrics

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Preliminary study on the causes of deviation of the northeast wind backflow snowstorm forecast in Liaoning region Aizhong ZHANG,Qi YAN,Lei GAO,Jinglong LU,Fangda TENG,Dan WU,Hongjie SHI 2023, 39 (5):  28-33.  doi: 10.3969/j.issn.1673-503X.2023.05.004 Abstract ( 130 )   HTML ( 12 )   PDF (3145KB) ( 272 )   Save Using the conventional observation data and NCEP FNL reanalysis data, the causes of a failed forecast snowstorm process were analyzed in the Liaoning region in early 2016.The results show that there are frontogenesis activities in the heavy snowfall area, and the frontogenesis is the direct cause of the intensification of snowstorms.Continuous frontogenesis occurs during snowfall, and the total frontogenesis function develops higher with time.The positive contribution of the horizontal deformation term to frontogenesis is greater during the heavy snowfall stage, especially when the contribution of elongation deformation to the horizontal deformation term is significant.The northeast wind in the eastern Liaoning provice and the easterly wind in the northern Yellow Sea both pass through the θse line, and the two air currents converge to form a narrow band with more dense θse contour lines.The clear contrast of temperature and humidity in this area produces frontogenesis.Under frontogenesis, the secondary circulation of the front is conducive to the development and maintenance of the upward movement, and the dynamic lifting and the enhancement of water vapor convergence lead to heavy snowfall weather.The frontogenesis caused by the enhancement of elongation deformation in the forecast is easy to ignore, which is the main cause of the snowfall forecast error.Therefore, the snowfall amount in the corresponding region can be revised to reduce the forecast error. Figures and Tables | References | Related Articles | Metrics

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Research on the applicability of high vertical resolution on radiation fog simulation around the Bohai Sea based on the WRF model Yunchen LIAO,Bingui WU,Tingting JU,Meng TIAN,Yinghua LI,Shupeng SUN,Jialin ZHANG,Jianbo YANG 2023, 39 (5):  34-43.  doi: 10.3969/j.issn.1673-503X.2023.05.005 Abstract ( 90 )   HTML ( 5 )   PDF (3235KB) ( 44 )   Save It is generally believed that a high vertical resolution numerical weather prediction model can improve the prediction ability of the fog formation stage, but there is much debate on whether the simulation ability of the fog development and disappearance stage can be improved.To explore the applicability of a high vertical resolution model for radiation fog simulation in the Bohai Sea Rim, three test indexes including probality of detection (POD), false alarm rate (FAR), and equitable threat score (ETS) were used to evaluate the simulation effect of different vertical resolution models for different stages of radiation fog process in the Bohai Sea Rim.The results show that setting a higher vertical resolution in the upper layer of the model has little effect on fog simulation, while setting a higher vertical resolution in the lower layer can generally improve the simulation ability of fog formation time, fog duration, and fog layer thickness, but the simulation of fog region highly depends on the fog distribution pattern.For the scattered and non-uniform fog process, the high vertical resolution model seems to improve the POD, but it is accompanied by the increase of FAR and the decrease of ETS.For the uniformly distributed fog process, the high vertical resolution model can improve all the test indexes simultaneously, and effectively improve the prediction of such type of fog process. Figures and Tables | References | Related Articles | Metrics

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Long-term variation of CO2 concentration at Longfengshan regional background station in Heilongjiang province from 2009 to 2019 Tongchuan XIE,Hujia ZHAO,Peng WANG,Jiageng DAI,Jingmin SUN,Xuli HOU,Mingjia LV,Wenbo MA,Ningwei LIU 2023, 39 (5):  44-52.  doi: 10.3969/j.issn.1673-503X.2023.05.006 Abstract ( 114 )   HTML ( 19 )   PDF (3819KB) ( 120 )   Save The long-term monitoring data of CO2 concentration in the Longfengshan regional atmospheric background station from 2009 to 2019 were used to analyze the daily, monthly, and interannual variation trends of CO2 concentration in Northeast China.The meteorological driving factors affecting the CO2 concentration of atmospheric background stations in the Longfengshan region were discussed.The results show that the diurnal variation of CO2 concentration in Longfengshan atmospheric background station is the largest in summer, followed by autumn, spring, and the smallest in winter.The daily peak value occurs before 08:00 and the lowest value occurs around 16:00.The monthly variation of CO2 concentration shows that the maximum value appears in January, with an average value of about 416.1×10-6, and the minimum value appeared in July, with an average value of 391.1×10-6.The seasonal variation of CO2 concentration shows that the CO2 concentration in winter is significantly higher than that in other seasons, with an average value of 415.4×10-6, and the lowest value appeared in summer, with an average value of 395.8×10-6.During the study period, the average CO2 concentration of Longfengshan station shows an increasing trend, with an annual growth rate of 2.45×10-6/a.At the Longfengshan background station, the maximum frequency wind direction appears in SSW direction in spring (21.0%), the maximum frequency wind direction appears in SSW and S direction in summer (23.1% and 22.7%), the maximum frequency wind direction appears in SSW direction in autumn (23.4%), and the maximum frequency wind direction appears in SW direction in winter (31.6%).The high CO2 concentration in different seasons occurs under the north wind dominant condition.There is a negative correlation between CO2 concentration and temperature (- 0.54), and a significant negative correlation between relative humidity and CO2 concentration in spring and autumn (- 0.44 and - 0.55).There is a small correlation between CO2 concentration and wind speed, which may be related to the transport of higher-concentration CO2 sources. Figures and Tables | References | Related Articles | Metrics

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Generation of meteorological element sequence for typical meteorological days of solar terms for long-term outdoor thermal environment simulation Junfeng LI,Jin ZHAO 2023, 39 (5):  53-61.  doi: 10.3969/j.issn.1673-503X.2023.05.007 Abstract ( 95 )   HTML ( 8 )   PDF (1962KB) ( 24 )   Save Long-term numerical simulation can describe the characteristics and change rules of outdoor thermal environments more comprehensively, which has an important theoretical and practical significance.At present, the meteorological data input in the simulation is mainly the typical meteorological days generated by the Finkelstein-Schafer (FS) statistical method or principal component analysis method, which is not continuous enough to describe the simulation scene.The solar term knowledge originates from the middle and lower reaches of the Yellow River in China.By combining the solar terms knowledge with the FS method, the typical solar terms with meteorological representative days are selected, and the solar term′s typical meteorological days (STTMD) can be generated for long-term outdoor thermal environment simulation.Based on the meteorological observation data from 1981 to 2010 and 1991 to 2020, the STTMD meteorological element data series of eight stations such as Zhengzhou and Ji′nan are generated, and the meteorological representation and application scope of the data were analyzed.The results show that the data has more accurate meteorological characterization in the middle and lower reaches of the Yellow River, which can greatly simplify the numerical simulation of long term, and has the possibility of further deepening and extending application.It is also found that the phenological significance of the data is not accurate enough for regions outside the middle and lower reaches of the Yellow River. Figures and Tables | References | Related Articles | Metrics

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Microclimatic characteristics of farmland at different growth stages of winter wheat in Northwest-Shandong Plain of China Baomei ZHU,Yijian YANG,Jibo ZHANG,Mi LI 2023, 39 (5):  62-71.  doi: 10.3969/j.issn.1673-503X.2023.05.008 Abstract ( 95 )   HTML ( 5 )   PDF (2030KB) ( 171 )   Save Using the data from the automatic field microclimate observation station in winter wheat main producing areas in Northwest-Shandong Plain of China and the national meteorological observation station in Qihe from January 2019 to June 2022, the microclimatic characteristics of winter wheat fields in different growth stages were analyzed, and the difference of climate between two observation stations was compared.The results were as follows at various growth stages of winter wheat, the air temperatures at different layers, total radiation, photosynthetically active radiation (PAR), wind velocity, and soil temperatures at the depth of 5~20 cm all present an obvious unimodal diurnal variation and the diurnal variation of relative humidity is opposite to that of air temperature.Air temperature in wheat fields decreases and increases with the increasing height above the ground in the daytime and nighttime, respectively.The relative humidity is highest at the height of 30 cm above the ground in all growth stages and reaches the maximum in the nighttime at the late growth stage and in the daytime at the middle growth stage.Soil temperature in each layer is highest at the late growth stage, and their diurnal variations decrease with the increasing soil depth.Daily average air and soil temperatures in farmland are lower than those in Qihe station, and the daily average relative humidity in farmland is higher than that in Qihe station.Both the total radiation and PAR are strongest at the late growth stage.The wind speeds of all layers show the same change trend at the early growth stage of winter wheat, while the wind speed at the height of 60 cm is most intensively affected by the growth and development of winter wheat.The air temperatures and relative humidities at different layers and soil temperatures at the depth of 5~10 cm in farmland show obvious diurnal changes under different weather conditions at the middle and late growth stages, and the above-mentioned situation is the most obvious in sunny days, followed by cloudy days and the weakest in overcast days. Figures and Tables | References | Related Articles | Metrics

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Characteristics and spatial representativeness of carbon flux of Phragmites communis wetland in the Liaohe River Delta, China Qiong WU,Rihong WEN,Qingyu JIA,Dawei ZHANG,Yijun ZHAO,Wenying YU,Xianzhe LIU,Nan WANG 2023, 39 (5):  72-81.  doi: 10.3969/j.issn.1673-503X.2023.05.009 Abstract ( 97 )   HTML ( 8 )   PDF (5240KB) ( 132 )   Save Based on observation data of carbon fluxes in the Liaohe River Delta from 2019 to 2020, the temporal change features of carbon fluxes in Phragmites communis wetlands in the Liaohe River Delta were analyzed and spatial representativeness of carbon fluxes was further investigated using the Kljun model.Results show that the net absorption cycle of Phragmites communis wetlands was 156 d under the influence of periodic changes in air temperature and shortwave radiation in 2019, the NEE peak value of -40.59 μmol·m-2 s-1 appeared in the first and middle ten-day of July, and carbon sequestration of 0.561 kgC·m-2 was higher than that in 2020.In 2020, the net absorption cycle was 131 d, and the NEE peak value of -41.39 μmol·m-2 s-1 appeared in mid-June, which was earlier than in 2019.The lower carbon sequestration ability was caused by stronger respiration at night during the growing season.Carbon fluxes showed an obvious "U-shaped" diurnal variation in spring and summer and varied stable in autumn and winter.The maximum daily average carbon fluxes in summers were -16.86 μmol·m-2 s-1 in 2019 and -13.61 μmol·m-2 s-1 in 2020, and appeared at 11:00 in 2020, which was earlier than in 2019.In addition, the distribution areas of the prevailing wind direction and the farthest distance contribution point of 90% of the unstable stratification status were in the direction of 0°~90° and the direction of 180°~270°.The average windward distance of 80% of the flux source region was 120 m at the farthest, while the flux contribution peak value appeared at 10 m far from the flux tower.The range of the source region expanded gradually with the increase in atmospheric stability, and that of 70% in the prevailing wind direction was distributed with reed vegetation providing 76.20% of carbon flux information, while the water body contributed 17.82% of carbon flux information.Flux observation data were at the representative level in the daytime of summer and an acceptable level all year round.The research helps to know the capacity and role of the wetlands ecosystem in the Liaohe River Delta in carbon cycling and carbon emission reduction. Figures and Tables | References | Related Articles | Metrics

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Cloud physical response of aircraft precipitation enhancement based on FY geostationary satellite Xiuzhu SHA,Can SONG,Jianfang DING,Ronghao CHU,Shanhai WANG 2023, 39 (5):  82-90.  doi: 10.3969/j.issn.1673-503X.2023.05.010 Abstract ( 52 )   HTML ( 4 )   PDF (4925KB) ( 82 )   Save Based on the precipitation enhancement operation data of aircraft from 2016 to 2019 and inversion products of FY-2E/2G/4A meteorological geostationary satellite, using the method of determining the affected area of precipitation enhancement by HYSPLIT model and the analysis method of satellite inversion product and radar product, the response of cloud physical parameters of satellite inversion after precipitation enhancement seeding was analyzed, the cloud physical characteristics and evolution law after precipitation enhancement seeding were obtained, and the comprehensive application ability and benefits of meteorological satellites in the inspection and evaluation of artificial precipitation enhancement effect were improved.The result shows that: for most of the precipitation enhancement operations in the study, the four cloud physical parameters under the influence of natural variation and artificial seeding reach the maximum variations in 2~3 hours after the end of seeding.For the 9 aircraft precipitation enhancement operations, average variation ranges of cloud top temperature, cloud effective radius, optical thickness, liquid water path, and hourly precipitation in 3 hours after the end of seeding reach -1.44~2.09 ℃, -3.73~3.84 μm, -5.47~3.62, -112.59~61.12 mm, -0.06~0.27 mm, respectively.Cloud top temperature and hourly precipitation are increased, and cloud effective radius, optical thickness, and liquid water path are decreased for more than half of the precipitation enhancement operations, and precipitation for individual operations is reduced.For different cloud bodies, when the distribution of liquid water and the structure of the cloud system vary dramatically and are very uneven, the variations of cloud physics and precipitation induced by precipitation enhancement seeding will be significantly different.At present, for the precipitation variation induced by natural variation and artificial seeding, it's difficult to eliminate the influence of the two factors on precipitation variation scientifically and completely. Figures and Tables | References | Related Articles | Metrics

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Characteristics of airborne pollen concentration in Beijing and its relationship with meteorological factors Jiang JIANG,Yuan QIAO,Chengying REN,Zhi JIANG,Huanling YOU,Caihua YE 2023, 39 (5):  91-98.  doi: 10.3969/j.issn.1673-503X.2023.05.011 Abstract ( 77 )   HTML ( 17 )   PDF (2532KB) ( 256 )   Save Using daily pollen concentration samples from 12 stations in Beijing during March 1 to September 30, from 2012 to 2020, spatial-temporal distribution characteristic of pollen concentration was analyzed.The results show that there are two peaks of pollen concentration with one in the spring pollen period (March-May) and the other in the summer-autumn pollen period (Autumn-September).The pollen concentration peak in spring is 3.3 times higher than that in summer and autumn.Pollen concentrations of 75% stations show an increasing trend during the studied period.The pollen concentration is lower during the intermittent period with its unobvious increasing trend.While in spring and summer-autumn, pollen concentration is higher with its obvious increasing trend.As a whole, daily average temperature, daily average relative humidity, and total daily precipitation are negatively correlated with pollen concentration.This result is consistent among the 12 stations.In addition, there is a stable correlation between wind speed, humidity, rainfall, and pollen concentration.However, the correlations between temperature, air pressure, and pollen concentration in different periods are more complicated, or even opposite. Figures and Tables | References | Related Articles | Metrics

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Risk analysis and zoning of frost damage for spring tea in Guizhou province Bo ZHANG,Sisi SUN,Liguo DING,Yan LIU,Fei YU 2023, 39 (5):  99-105.  doi: 10.3969/j.issn.1673-503X.2023.05.012 Abstract ( 77 )   HTML ( 5 )   PDF (2936KB) ( 119 )   Save To reduce the economic losses and improve the ability of tea production to resist meteorological disasters, the risk analysis of frost damage during the spring tea growing season was carried out based on the daily minimum temperature data of 84 meteorological stations in Guizhou province from 1961 to 2020, and the frost damage risk index was constructed using the methods of mathematical statistics and spatial analysis.The results show that light frost damage is the main disaster of spring tea in Guizhou province.The number of days frost occurred and the station ratio of frost for each grade shows a decreasing trend.The frost damage risk level is high in the west and the north, becomes lower in the east and the south.The areas with sub-high risk are mainly distributed in the north of Liupanshui, the most of the west and the middle of Bijie, the part of the northern Guiyang, the part of the Daloushan in the north of Zunyi, Fanjing Mountain Area in the middle of Tongren, Leigong Mountain Area in the southeast of Guizhou province and Doupeng Mountain Area in Southern Guizhou province.The total area is about 3.7×104 km2, accounting for 21.7% of the entire area of Guizhou province.The lowest risk areas are mainly distributed in the Beipanjiang River Basin in the southwest Chishui River Basin in the north and Duliu River Basin in the southeast and the area is about 2.34×104 km2, accounting for 14.3% of the total area of Guizhou province. Figures and Tables | References | Related Articles | Metrics

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Experimental study on thunderstorm forecast of ground-based microwave radiometer based on BP neural network Weidong JIANG,Rongzhi ZHANG,Bo CHEN,Tianqi ZHANG,Hailing HUANG,Lin ZHOU 2023, 39 (5):  106-112.  doi: 10.3969/j.issn.1673-503X.2023.05.013 Abstract ( 80 )   HTML ( 6 )   PDF (1334KB) ( 198 )   Save Using the MWP967KV ground-based microwave radiometer data at Shanghai Pudong International Airport Ground Meteorological Observation Station from 2018 to 2019, the civil aviation surface observation data, and the conventional sounding data of Baoshan Station, we analyzed the reliability of the microwave radiometer detection data.On this basis, we calculated the atmospheric parameters related to the occurrence of thunderstorms, selected the appropriate parameters as the forecasting factors, established the BP (Back Propagation) artificial neural network model for airport thunderstorm forecast, and evaluated the forecasting effect of the model.The results show that the mean absolute deviations of temperature, relative humidity, and water vapor density obtained by the MWP967KV ground-based microwave radiometer with the corresponding sounding data are 1.94 ℃, 16.05%, and 0.82 g·m-3, respectively, the root mean square errors are 1.41 ℃, 20.14%, 1.90 g·m-3, respectively, and the correlation coefficients are 0.99, 0.66, and 0.85, respectively.The established BPNN model can predict the occurrence of thunderstorms accurately.The forecast accuracy rates of 2 h, 3 h, and 6 h reach 93.27%, 93.33%, and 89.47%, respectively, and the missing rates are 6.73%, 6.67% and 10.53%, respectively.The reporting rates reach 4.90%, 4.78%, and 2.86%, and the critical success indices reach 89.99%, 80.33% and 81.18%, respectively.Therefore, this study realizes the intelligent forecast of thunderstorms to some extent, and the model can be applied to the forecasting and early warning of thunderstorm weather at airports and single stations. Figures and Tables | References | Related Articles | Metrics