2020, 43(5):745-767. DOI: 10.13878/j.cnki.dqkxxb.20200905017
Abstract:This paper introduces the development of short-term climate prediction in China and abroad from the perspective of scientific development.On this basis,it reviews the growth of short-term climate prediction teams and the related teaching,scientific research and operational practice in Nanjing University of Information Science & Technology (NUIST) since its establishment 60 years ago,and provides an outlook for the future work.
HE Jinhai , XU Haiming , WANG Lijuan , QI Li , ZHU Zhiwei , MA Jing , LUO Jingjia
2020, 43(5):768-784. DOI: 10.13878/j.cnki.dqkxxb.20200903001
Abstract:This paper reviews the main course of monsoon research in Nanjing University of Information Science and Technology (NUIST) since the founding of NUIST 60 years ago,and the important achievements in the Asian monsoon,especially in the East Asian monsoon.From 1980s to early 2000s,the successful implementation of the PRC-US,PRC-Japan cooperated monsoon research projects and the “South China Sea Monsoon Experiment” has greatly promoted the formation and growth of the monsoon research team in NUIST,and also contributed to a series of innovative achievements.First,the atmospheric circulation differences between the East Asian monsoon and the Indian monsoon were revealed,and the clear concept of the East Asian subtropical monsoon was proposed.Second,an earlier onset of the East Asian subtropical summer monsoon than the South China Sea summer monsoon with the former independent of the latter was found.Third,the Asian-Australian “land bridge” was identified as the region with the most active convections in the Asian monsoon region in the Northern Hemisphere in spring,and the associated convection occurrence and northward advancement play a vital role in the onset of the East Asian summer monsoon.Fourth,the northward-propagation characteristics and mechanism of the summer intraseasonal oscillation over the East Asian monsoon region were unraveled and successfully applied to the extended-range forecast.These innovative achievements have made great contributions to the monsoon research.In recent years,NUIST has been adhering to the idea of “Open Development and Joint Development” and vigorously introducing high-level talents,which further contribute to the monsoon research.As one of the important teams dedicated to international monsoon research,NUIST monsoon research team will keep deepening the understanding of monsoon theory and improving the level of monsoon forecast.
JIANG Zhihong , WENG Duming , TU Qipu , MIAO Qilong , WU Xi , YU Jinhua
2020, 43(5):785-801. DOI: 10.13878/j.cnki.dqkxxb.20200915001
Abstract:This article briefly reviews the research on climate and climate change in NUIST since 1960,and summarizes the important academic findings in such aspects of climate science as radiation climatology,applied climatology,climate diagnosis and prediction,statistical climatology,climate change and its regional response and future projections.
YUAN Feng , ZHANG Junzhi , WANG Ji , WANG Rong
2020, 43(5):802-809. DOI: 10.13878/j.cnki.dqkxxb.20191129001
Abstract:In recent years,with the rapid development of cities and the improvement of drainage design requirements,it is particularly important to study the characteristics and patterns of urban rainstorm.Based on the minute-by-minute rainfall data of Beijing Observatory station during 1961—2017,according to the Technical Guidelines for Establishment of Intensity-Duration-Frequency Curve and Design Rainstorm Profile,this paper established the rainstorm intensity formulas in Beijing under the two climate states of 1961—1990 and 1991—2017,and the design rainstorm patterns of 30 min,60 min,90 min,120 min,150 min and 180 min durations with 5 min as the time period under the two-year return period.Results show that:(1) The P-Ⅲ pattern distribution curve has the best fitting effect on the rainfall of each duration under the two climate states in Beijing,and the rainstorm intensity formula has the highest precision.(2) Compared with the rainstorm intensity formulas of 1961—1990 and 1991—2017,on the whole,the rainstorm intensity value of the latter under each return period is lower,but with the increase of return period,the difference in rainfall intensity between them increases.(3) During 1961—1990 and 1991—2017,the location coefficients of short duration rainstorm peaks are 0.436 and 0.382,respectively.Under the two-year return period,the positions of rain peaks during 1961—1990 are earlier than those during1991—2017.The accumulated rainfall of each duration increases slowly in the initial stage,increases rapidly before and after the rain peak,and then slows down significantly.
HE Lihua , WANG Yongqing , LONG Linxue , YAN Xuejin , GENG Fei , CHEN Biying , ZHANG Yingxin
2020, 43(5):810-823. DOI: 10.13878/j.cnki.dqkxxb.20191104002
Abstract:On the morning of July 21,2017,a localized rainstorm event occurred in Shijiazhuang,with the heavy rain mainly concentrating in its urban area,eastern and northern parts,which was omitted by both numerical and subjective forecasts.In this paper,the triggering mechanisms of the mesoscale convective system(MCS) causing this rainstorm,the propagation direction of the system and the main factors affecting the overall movement were analyzed by using the intensified surface observation data,Doppler radar data,radar wind profile,the four-dimensional variational Doppler radar analysis system(VDRAS) and NCEP reanalysis data.The results show that:1)Before the heavy precipitation occurring,a large amount of unstable energy was accumulated because of the high temperature and high humidity in this area.The surface airflow was turned by Taihang Mountain in the vicinity of Shijiazhuang,forming the shear line of northeast wind and west-northwest wind in front of the mountain.The strong thunderstorm high and cold pool was formed by the heavy precipitation in Qinhuangdao and Tangshan areas.The pressure gradient force generated by the thunderstorm high strengthened the northeast wind,which guiding the cold pool to gradually move southwest in a tongue shape to the north of Shijiazhuang area.In the vicinity of the aforementioned shear line,an unstable stratification of low-level convergence and middle-level divergence was formed,which was combined with the topographic forced uplift of the windward slope triggering the unstable energy release.2)During the development and strengthening of thunderstorm,the cold outflow formed by the precipitation of MCS moved slowly in the northeast direction.In the area where the northeast airflow was converged,new thunderstorms were constantly triggered,which made thunderstorms spread northeast.At this stage,the average wind speed of the storm bearing layer(ie,the translation direction of the MCS) was small,the system was stable and less moving,mainly in the form of “backward propagation”,which was shown as “quasi-static state”.With the increase of the average wind speed in the storm bearing layer,the moving direction of the MCS could be synthesized from the reverse vector of the low-level jet and the average wind vector above 1.5 Km(between 850 and 300 hPa layers).At this stage,the moving direction of the cold pool was closely related to the average wind in the storm bearing layer,causing the thunderstorm cold outflow moving southeast.The northwest cold outflow of the cold pool formed the convergence with the southeast warm environmental flow,leading to the constantly emerging thunderstorm cells in the front of the MCS.The propagation direction was consistent with the advection direction,and the system moved “fast” to the southeast.
GAO Mei , CAO Xiaoqun , LIU Bainian , HAN Zihang , HOU Shicheng , YANG Guogui
2020, 43(5):824-833. DOI: 10.13878/j.cnki.dqkxxb.20190516001
Abstract:In this paper,a method of Dynamic Mode Decomposition(DMD) is proposed,so as to analyze the atmospheric motion data,with the aim of improving our understanding of atmospheric motion characteristics.The modal analysis of the 200 hPa jet is performed using the DMD method,andthe main modes,along with theircorresponding frequency and the decay/growth rate of flow,are obtained.Next,a dynamic reduced-order model of the evolution of the 200 hPa jet is established,which is able to reconstruct and predict the dynamic development process of the jet.The study results confirm that the DMD method is able to successfully capture the flow structures of different scales of the 200 hPa jet stream flow.The results also illustrate the differences between the flow with different frequencies,by comparing and analyzing the flow field information contained in the first 6-order main modes,thereby indicating the advantages of the DMD method in modal decomposition of complex atmospheric dynamic systems.The comparisons between the real and reconstructed flow fields by the mode superposition at different times indicate that the first 6-order modes contain the greatest amount of information regarding the original flow fields,from which they can be accurately reconstructed.
CHEN Wei , GUAN Zhaoyong , YANG Huadong
2020, 43(5):834-844. DOI: 10.13878/j.cnki.dqkxxb.20200616001
Abstract:Complementary relationships between the East Asian summer monsoon and the Australian winter monsoon have a significant impact on the climate anomalies in the Northern and Southern Hemispheres.Using the National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR) reanalysis data,the Hadley Centre Global Sea Surface Temperature dataset,and the CPC Merged Analysis of Precipitation (CMAP) data,based on the joint index of East Asian-Australian monsoon,this paper investigated the reverse variation characteristics of the East Asian summer monsoon and Australian winter monsoon intensities.Results show that when the East Asian summer monsoon is stronger and the Australian winter monsoon is weaker,complex anomalous circulation systems appear in the middle and low latitudes of the Northern and Southern Hemispheres.In the lower troposphere of the tropical region,the anomalous anticyclonic circulation system in the northwestern Pacific is intensified,which is coupled with the anomalous anticyclonic circulation in the South Pacific Convergence Zone(SPCZ),forming an anomalous easterlies near the equator,while there are two anomalous cyclonic circulation systems in the northern and southern Indian Ocean.In the marine continental area between the two pairs of anomalous circulations,the anticyclonic circulation is located in the south of the equator and the cyclonic circulation in the north of the equator.In the East Asian monsoon region,there is an anticyclone anomaly on the east side of the southeast coast of China,and southeastern China is affected by the southeast wind on the southwest side of the anomalous anticyclone.In addition,the northern Australia is affected by the anomalous westerly wind.As a result,the East Asian summer monsoon is stronger and the Australian winter monsoon is weaker,which leads to a complementary relationship between them.When the East Asian summer monsoon is weaker and the Australian winter monsoon is stronger,the circulation characteristics of the Northern and Southern Hemispheres are opposite to the above.On the whole,when the East Asian summer monsoon is stronger and the Australian winter monsoon is weaker,different climate anomaly distribution characteristics appear in the Northern and Southern Hemispheres of the East Asian-Australian monsoon area,that is,the precipitation is less in the north(east) but more in the south(west) and the temperature is higher in the north(west) and lower in the south(east) in the Northern(Southern) Hemisphere.
GUO Qiyun , QIAN Yuan , YANG Rongkang , CAO Xiaozhong
2020, 43(5):845-855. DOI: 10.13878/j.cnki.dqkxxb.20180525001
Abstract:For many years,the quality of radar wind measurement data has been the focus of many scholars.However,there have few studies performed on the assessment of radar wind measurement data,and the evaluation process is relatively simple,lacking more comprehensive and in-depth research and discussion.In addition,no quantitative evaluation criteria have been created through statistical parameters,and most of have not been quality controlled according to the evaluation results.In order to resolve the above issues,related research is currently being carried out.In this study,taking the FNL reanalysis fields of NCEP and GRAPES initial estimation fields in China as the references,the L-band radar wind measurement taken from the Beijing Sounding Station is evaluated from the multi-parameters,such as average deviations,standard deviations,probability density distributions,kurtosis coefficients,skewness coefficients,correlation coefficient and root mean square error.Then,according to the assessment results,the data of the radar wind are controlled,and the parameters are again solved,so as to further evaluate the quality control effect.The test results show that the L-band radar wind measurement is of high quality,while the average deviation is within ±1 m/s,and its consistency with the reference standard decreases with the decrease of the air pressure.The consistency of the east-west and north-south components of wind remains basically the same.The data consistency of the summer season is highest in the four seasons.The evaluation results based on FNL are shown to be superior to those of the GRAPES forecast field.All parameters based on FNL are closer to the optimal values relative to the parameters of GRAPES.Based on the evaluation results,after quality control the consistency of the wind measurement data is shown to be improved,and the original characteristics are retained.The quality control method can effectively eliminate seasonal differences,while the gap between the assessment results of the two background fields is also narrowed following quality control.
2020, 43(5):856-866. DOI: 10.13878/j.cnki.dqkxxb.20181012002
Abstract:The Infrared Atmospheric Sounding Interferometer(IASI) is applied to perform cloud detection,by using the different responses to clouds between longwave and shortwave channels at CO2 bands.First,IASI longwave channels are paired with shortwave channels based on weighing function altitudes and sensitivity to clouds.A linear relationship of the brightness temperatures between each pair of channels is then established to predict the shortwave channel from the longwave channel under clear sky conditions.Finally,a cloud emission and scattering index(CESI) can be defined as the difference in the paired shortwave channel between the regression model predicted and the observed brightness temperatures.The spatial distribution of the CESIs with weighting functions peaking at around 383 hPa is consistent with that of the cloud phase of ice,especially at the equator and low latitudes.The spatial distribution of CESIs with weighting functions peaking at around 790 hPa agrees well with the distribution of the low cloud top pressure.
ZHI Xiefei , DONG Fu , ZHANG Ling , JI Luying , ZHU Shoupeng
2020, 43(5):867-879. DOI: 10.13878/j.cnki.dqkxxb.20200106001
Abstract:In this study,eight cloud microphysics parameterization schemes(Lin,WSM6,Thompson,Morrison 2-mon,CAM5.1,WDM5,WDM6 and NSSL 2-mon) in WRFV3.6.1 were applied to simulate six classical southerly types of warm-sector heavy rainfall(WSHR) during the rainy season over coastal Guangxi during the period of 2010-2016.The simulation results and ensemble mean(EMN) results are evaluated by the Method for Object-based Diagnostic Evaluation(MODE).In most cases,the WRF model was able to accurately simulate the rain belt of WSHR.The WSM6 scheme performed best on average,followed by the Lin scheme.In contrast,CAM5.1 and NSSL 2-mon were the schemes that exhibited the poorest simulations.It was also found that the dynamic and cloud microphysical characteristics of various schemes showed different performance.Based on the single scheme simulation results,the ensemble mean forecasting experiments were carried out according to the method of EMN,the results of which suggested that the EMN is able to reduce the forecast uncertainly of the model,and in turn produce more stable forecast results.
2020, 43(5):880-887. DOI: 10.13878/j.cnki.dqkxxb.20180106001
Abstract:The whole India summer rainfall data set from the Indian Institute of Tropical Meteorology,monthly Reanalysis data set from European Center for Medium-Range Weather Forecasts(ECMWF),Japan Meteorological Agency/Japan(JRA-55) and National Center for Environment Prediction/National Center for Atmospheric Research(NCEP/NCAR) during 1958—2014 are used to study the relations between Somali jet and Indian summer rainfall.It is found that before 1983,SMJ had significant positive correlation with the Indian summer rainfall,which accorded with our past understanding.But after 1983,the positive correlation has significantly weakened.Further study indicated that before 1983,there was a positive anomaly of the Somali equatorial airflow in the South India ocean and the Somali coast and there was a positive anomalous southwest wind in the Arabia sea and the northwest of India,which increased the summer water vapor transport to India and further strengthened Indian summer precipitation.SMJ was closely related to the South Asia high.However,after 1983,the south-west wind positive anomaly in the north of the Arabia sea and the northwest of India has weakened,particularly in the west coast of India.The correlation between SMJ and the South Asia high has also weakened,which results in the weakening correlation between SMJ and Indian summer rainfall.In addition,while the relations between Indian summer rainfall and ENSO,SMJ are weakening,it is preliminarily shown that the correlation between Indian summer rainfall and East Asia/Pacific Teleconnection (EAP) is significantly strengthening.
DUAN Mingkeng , LI Xin , WANG Panxing
2020, 43(5):888-896. DOI: 10.13878/j.cnki.dqkxxb.20200220001
Abstract:Based on the temperature and precipitation data of 160 stations in China from 1951 to 2010,this paper analyzed the climate average and climate variability of temperature and precipitation in winter and summer at the representative stations in China,as well as their differences between the former and later 30 years.Furthermore,the differences are tested by two different types of significance test methods.Results show that the change of climate average of seasonal temperature is generally consistent with the global warming,mainly warming up,but a significant local cooling phenomenon occurs in the south of Qinling Mountains and the middle reaches of the Yangtze River in summer.The change of climate variability of seasonal temperature is relatively small,and the overall change in winter is not significant,and only a few stations change significantly in summer.The climate change of seasonal total precipitation is not obvious on the whole.The spatial distribution of seasonal precipitation climate value changes is complex,and it increases in southern China in winter and eastern China in summer,while the changes of climate variability of winter and summer precipitation are not significant.For the differences of significance test results between the theoretical test method (t-test and F-test) and the stochastic simulation method (EMC (empirical Monte Carlo) method),they are small for the temperature and relatively large for the precipitation,which is related to whether the sample anomaly series obeys the normal distribution.Under the condition that the statistical characteristics of the samples remain unchanged,the EMC method can make the test results more reliable by multiple random simulations without considering the theoretical statistical distribution characteristics of the samples.
MA Hongyun , HAN Lujie , GU Chunli
2020, 43(5):897-907. DOI: 10.13878/j.cnki.dqkxxb.20180111001
Abstract:WRF3.8.1 model was chosen to simulate a rainstorm process in Nanjing in early June 2014 with Thompson cloud microphysics parameterization scheme.The effects of cloud condensation nuclei (CCN) concentration on the rainstorm were compared by two numerical experiments,which represent the high and low CCN concentrations,respectively.Results show that:(1) Thompson scheme can reproduce the rainstorm process to a certain extent,but the simulation of 24 h cumulative precipitation is generally low,and the cumulative precipitation increases with the increase of CCN concentration.The higher CCN concentration is beneficial to the enhancement of heavy precipitation centers and the expansion of heavy precipitation range,while it has the opposite effect on the weak precipitation centers.(2) The increase of CCN concentration will inhibit the transformation of cloud droplets to raindrops,more cloud droplets will be transported to the middle troposphere,and the warm cloud process in the lower troposphere will be inhibited.(3) The increase of CCN concentration increases the supercooled cloudwater in the middle troposphere,promotes the transformation of supercooled cloudwater to graupel,and promotes the riming process of droplets onto snow,which is conducive to the development of cold cloud process.(4) The increase of CCN concentration has negative feedback effect on warm cloud process and positive feedback effect on cold cloud process.
HUANG Xingyou , LU Lin , HONG Tao , MEI Yao , YANG Min
2020, 43(5):908-916. DOI: 10.13878/j.cnki.dqkxxb.20180203003
Abstract:Clouds exert an important influence on the weather and precipitation.The detection of cloud microphysical parameters(particle effective radius,drop number concentration,etc.),as well as of macro-physical parameters(cloud height,cloud thickness),is essential to studying cloud physical process and cloud radiation effects.The present paper aims to perform the detection and retrieval of cloud parameters and in-cloud turbulence characteristics with a ground-based millimeter cloud radar.By applying the Doppler spectrum data,the ambient vertical air velocity and cloud microphysical parameters are solved,whereby the turbulent dissipation rate ε and its distribution are obtained.Next,the relationships of vertical air motion to cloud microphysical parameters,radar reflectivity factor,Doppler velocity and Doppler spectrum width are thoroughly studied and analyzed so as to aid in understanding the cloud evolution.Cloud radar measurements and retrievals performed on a Stratiform cloud process case at Daocheng,Sichuan on August 8,2016 reveal the following:1)The cloud particle effective radius increases as the updraft increase,and the cloud drop number concentration decreases accordingly due to the collision-coalescence process;2)The turbulent dissipation rates ε are strong the near cloud base and cloud top,and weak in the middle layer,ranging from 10-8 to 10-2 m2·s-3.The Doppler spectrum validates the hypotheses that the turbulent scale captured by cloud radar is in the inertial subrange;3)As the air updraft grows stronger,the cloud particles deposition speed is weakened,while the Doppler spectrum width is strengthened.
TANG Yahui , ZHOU Yuquan , CAI Miao , MA Qianrong
2020, 43(5):917-931. DOI: 10.13878/j.cnki.dqkxxb.20180104001
Abstract:This study,using the CloudSat and CALIPSO data products from 2007 to 2010,statistically analyzed the horizontal and vertical distribution characteristics of cloud cover and frequency of clouds.Subsequently,the study then compared the results with CloudSat data alone,so as to discuss the spatial distribution characteristic of clouds as observed by CALIPSO.The results show that the global mean total cloud amount is 0.69,with the high values mainly concentrated in the southern hemisphere near the 60°S westerlies,north Pacific storm track and equatorial convergence zone(ITCZ),and low values occurring in the North African desert regions and northern Indian Ocean.The distribution of total cloud amount obtained by the CloudSat/CALIPSO data is basically consistent with that obtained by various cloud observations such as CERES,yet the CloudSat/CALIPSO combination data are able to better respond to the cloud vertical structure,and provide a stronger basis for the global cloud region.Upon comparing the statistical results of the joint observations with the distribution results of clouds using CloudSat data alone,it was determined that high ice clouds over land could be detected more accurately by CALIPSO rather than by radar.In addition,with the decrease in temperature,the advantage of the identification of clouds becomes more apparent.At the same time,CALIPSO is also able to observe some warm clouds with thinner upper cloud optical thickness and no precipitation,as well as small particle size.Ice clouds observed by CALIPSO which have a small particle radius on the top are mainly distributed in the ITCZ,the southern hemisphere near 60°S westerlies and north Pacific storm track belt region.These warm clouds with no precipitation are mainly found in the 10—20 ℃ temperature range of North and South America and South Africa's west coast,while supercooled water clouds are mainly found in the -10—0 ℃ temperature range of the southern hemisphere near the 60°S westerlies.
CHEN Aijun , MENG Wentong , HU Shenshen , BIAN Lingen
2020, 43(5):932-942. DOI: 10.13878/j.cnki.dqkxxb.20171030001
Abstract:In this paper,the spatial distribution continuity and ratio of the high-quality retrievals over the Tibetan Plateau of two land surface albedo products,namely MODIS(MODerate resolution Imaging Spectroradiometer)land surface albedo and GLASS (Global LAnd Surface Satellite Products System)land surface albedo,were comparatively analyzed.Next,the accuracies of these two products were evaluated using the high-precision ground observation data obtained during the CAMP/Tibet experiments.Furthermore,the factors affecting the accuracies of these two products were analyzed through artificial visual interpretation combined with the MODIS snow product.The results of the study are as follows:1)The product of the GLASS land surface albedo is superior to that of the MODIS land surface albedo in terms of both spatial distribution continuity and the ratio of the high-quality retrievals.2)These two products both have high consistency with land surface albedo ground measurements during most of the retrieval periods,and rather accurately reflect the abnormal changing processes of land surface albedo.3)The patchy snow is an important factor affecting the accuracies of these two products when performing comparison with the ground measurements.4)The inversion algorithm of the GLASS land surface albedo has a great advantage over that of the MODIS land surface albedo under snow conditions.The above results are conducive to the users to acquiring better knowledge of these two products.In addition,the results also contribute to the improvements of the algorithm of satellite remote sensing land surface albedo over the Tibetan Plateau,so as to assist in obtaining retrievals with better precision,quality and spatial distribution continuity.
2020, 43(5):943-952. DOI: 10.13878/j.cnki.dqkxxb.20200806001
Abstract:This paper introduces Prof.Pengfei Wang's outstanding contribution to the study of Chinese Meteorological History and Meteorological Affairs Recordkeeping,a field in which Prof.Pengfei Wang is a pioneer and leading researcher.His wisdom and diligent efforts have pushed the research of Chinese Meteorological History to new levels.Through his dedication and perseverance,he has made great contributions to the deepening and advancement of the study of Chinese Meteorological History.Although the results introduced in the paper were achieved by Prof.Pengfei Wang's many years ago,they still have the specific guiding roles in today's prosperous Meteorological History research.This year marks the 60th anniversary of Nanjing University of Information Science and Technology,of which Prof.Pengfei Wang is one of the founders of the University,and to which he has made outstanding contributions to the National Double first-class discipline of the University.2020 also marks the 100th anniversary of Prof.Pengfei Wang's birth,and this article also serves as a sincere commemoration to his achievements.
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