ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 42,Issue 1,2016 Table of Contents
ZHENG Yongguang
,
TIAN Fuyou
,
MENG Zhiyong
,
XUE Ming
,
YAO Dan
,
BAI Lanqiang
,
ZHOU Xiaoxia
,
MAO Xu
,
WANG Mingjun
2016, 42(1):1-13.
DOI: 10.7519/j.issn.1000-0526.2016.01.001
Abstract:
The extraordinarily serious capsizing accident of the cruise ship, named Dongfangzhixing (Eastern Star), occurred at around 21:30 BT 1 June 2015, in the Jianli (Hubei Province) section of the Yangtze River. Based on the results of the wind damage survey with satellite and radar data analyses, this paper presents that the high wind damage was caused by downbursts and one likely tornado over the area surrounding the event occurring site at around 21:00-21:40 BT 1 June, with the most intense Beaufort scale more than level 12, and the characteristics of discontinuous and multiscale spatial distribution and very small spatiotemporal scale of the most severe wind damage. The wind damage over the northern land part of the surrounding area (Shunxingcun, Laotai Deep Water Wharf, Sitaicun, Xingouzi) affected by one mesocyclone is more significant than the southern land part behind the gust front and microbursts. It is determined that one likely tornado occurred at Laotai Deep Water Wharf, and the wind damage at other sites was caused by microbursts based on the radar data and damage survey. The flows in the convective storm causing wind damage have obvious multiscale characteristics, and a number of microburst swathes simultaneously occurred at the woods of Sitaicun located in the northern part of the surrounding area, with alternate spatial distribution of divergence and convergence, displaying a feature of the complicated atmospheric motion in the convective storm. Although mesovortices occur within a microburst, the horizontal scale of convergence within the microburst found in this wind damage survey was only tens of meters and far less than the severalkilometer horizontal scale of bookend vortices or mesovortices within a bow echo.
The extraordinarily serious capsizing accident of the cruise ship, named Dongfangzhixing (Eastern Star), occurred at around 21:30 BT 1 June 2015, in the Jianli (Hubei Province) section of the Yangtze River. Based on the results of the wind damage survey with satellite and radar data analyses, this paper presents that the high wind damage was caused by downbursts and one likely tornado over the area surrounding the event occurring site at around 21:00-21:40 BT 1 June, with the most intense Beaufort scale more than level 12, and the characteristics of discontinuous and multiscale spatial distribution and very small spatiotemporal scale of the most severe wind damage. The wind damage over the northern land part of the surrounding area (Shunxingcun, Laotai Deep Water Wharf, Sitaicun, Xingouzi) affected by one mesocyclone is more significant than the southern land part behind the gust front and microbursts. It is determined that one likely tornado occurred at Laotai Deep Water Wharf, and the wind damage at other sites was caused by microbursts based on the radar data and damage survey. The flows in the convective storm causing wind damage have obvious multiscale characteristics, and a number of microburst swathes simultaneously occurred at the woods of Sitaicun located in the northern part of the surrounding area, with alternate spatial distribution of divergence and convergence, displaying a feature of the complicated atmospheric motion in the convective storm. Although mesovortices occur within a microburst, the horizontal scale of convergence within the microburst found in this wind damage survey was only tens of meters and far less than the severalkilometer horizontal scale of bookend vortices or mesovortices within a bow echo.
2016, 42(1):14-25.
DOI: 10.7519/j.issn.1000-0526.2016.01.002
Abstract:
Thunderstorms were generated in a weak vertical wind shear and strong unstable environment beginning from noon 1 August 2013 in Shanghai. During the developing process of the thunderstorms, three mesocyclones were detected, and especially during the formation of the second mesocyclone, characteristics of a classic supercell were found after the merging of two storms, such as lowlevel hook, pendant echoes, mesocyclone and TBSS (threebody scatter spike). Using conventional weather observations, dual Doppler radar data, automatic weather station data and wind profile radar data, the main formation mechanisms of the first two mesocyclone’s were found to be as follows: (1) the join of the previous thunderstorms’ outflow strengthens the environmental convergence and intensifies the lift of warm and moist air. (2) The outflow of thunderstorms strengthens the lowlevel vertical wind shear which is favorable for the formation of mesocyclone. In addition, due to the merging of the two thunderstorms, the intensified updraft and the strengthened rotation of the strom play important roles in the formation of the supercell mesocyclone. Then, during the formation of the third mesocyclone, the outflow of the storm was lifted by the downdraft of the adjacent storm, thus the rotation of the outflow and inflow in the mid and lowlevel was detected as the mesocyclone.
Thunderstorms were generated in a weak vertical wind shear and strong unstable environment beginning from noon 1 August 2013 in Shanghai. During the developing process of the thunderstorms, three mesocyclones were detected, and especially during the formation of the second mesocyclone, characteristics of a classic supercell were found after the merging of two storms, such as lowlevel hook, pendant echoes, mesocyclone and TBSS (threebody scatter spike). Using conventional weather observations, dual Doppler radar data, automatic weather station data and wind profile radar data, the main formation mechanisms of the first two mesocyclone’s were found to be as follows: (1) the join of the previous thunderstorms’ outflow strengthens the environmental convergence and intensifies the lift of warm and moist air. (2) The outflow of thunderstorms strengthens the lowlevel vertical wind shear which is favorable for the formation of mesocyclone. In addition, due to the merging of the two thunderstorms, the intensified updraft and the strengthened rotation of the strom play important roles in the formation of the supercell mesocyclone. Then, during the formation of the third mesocyclone, the outflow of the storm was lifted by the downdraft of the adjacent storm, thus the rotation of the outflow and inflow in the mid and lowlevel was detected as the mesocyclone.
2016, 42(1):26-33.
DOI: 10.7519/j.issn.1000-0526.2016.01.003
Abstract:
A windprofiling radar network of China is designed. The assimilation of windprofiling radar observations anticipated from this network is conducted as a series of observing system simulation experiments (OSSEs) to study its impact on the GRAPES_MESO model system in a case of south shear line weather. In this OSSEs study, a control simulation without any data assimilated is compared to four OSSE simulations that assimilated windprofiling radar or sounding data. The rootmeansquare error (RMSE) of wind analysis is compared against the control simulation. A significant increase of RMSE of wind analysis is found obviously below 500 hPa level when the wind profile data are used in the assimilation system. The obvious improvement from inclusion of wind profile for RMSE of wind analysis is below 300 hPa roundly. When the wind profile data of troposphere II type are assimilated RMSE of wind analysis is a little larger than that when the wind profile data of boundary layer type are assimilated. The results show the two types of windprofiling radar neither improve the rainfall prediction obviously, but the rainfall prediction is improved when the sounding data are also assimilated together.
A windprofiling radar network of China is designed. The assimilation of windprofiling radar observations anticipated from this network is conducted as a series of observing system simulation experiments (OSSEs) to study its impact on the GRAPES_MESO model system in a case of south shear line weather. In this OSSEs study, a control simulation without any data assimilated is compared to four OSSE simulations that assimilated windprofiling radar or sounding data. The rootmeansquare error (RMSE) of wind analysis is compared against the control simulation. A significant increase of RMSE of wind analysis is found obviously below 500 hPa level when the wind profile data are used in the assimilation system. The obvious improvement from inclusion of wind profile for RMSE of wind analysis is below 300 hPa roundly. When the wind profile data of troposphere II type are assimilated RMSE of wind analysis is a little larger than that when the wind profile data of boundary layer type are assimilated. The results show the two types of windprofiling radar neither improve the rainfall prediction obviously, but the rainfall prediction is improved when the sounding data are also assimilated together.
2016, 42(1):34-43.
DOI: 10.7519/j.issn.1000-0526.2016.01.004
Abstract:
On the basis of GRAPES_3Dvar system, the insertion of preprocessed module and assimilation module for Doppler radar radial velocity assimilation are conducted (including traditional and advanced emulators respectively). In this paper, the rain case on 6 June 2014 is selected to perform the assimilation and prediction experiments using the GRAPES_3Dvar system after the accuracy test, analyzing the impact on the adjustment of initial conditions and precipitation simulations through different emulators. The results indicate that the mesoscale information increases after assimilating radar radial velocity. Moreover, by comprehensively analyzing the radial and tangential components, the results using the advanced emulator approach are closer to observation and reference wind fields compared with those using the traditional one. In addition, the accumulated precipitation result adopting the advanced emulator can better simulate the location and magnitude of precipitation and effectively restrain the virtual rainfall among all tests, the test scores also illustrate this conclusion.
On the basis of GRAPES_3Dvar system, the insertion of preprocessed module and assimilation module for Doppler radar radial velocity assimilation are conducted (including traditional and advanced emulators respectively). In this paper, the rain case on 6 June 2014 is selected to perform the assimilation and prediction experiments using the GRAPES_3Dvar system after the accuracy test, analyzing the impact on the adjustment of initial conditions and precipitation simulations through different emulators. The results indicate that the mesoscale information increases after assimilating radar radial velocity. Moreover, by comprehensively analyzing the radial and tangential components, the results using the advanced emulator approach are closer to observation and reference wind fields compared with those using the traditional one. In addition, the accumulated precipitation result adopting the advanced emulator can better simulate the location and magnitude of precipitation and effectively restrain the virtual rainfall among all tests, the test scores also illustrate this conclusion.
2016, 42(1):44-53.
DOI: 10.7519/j.issn.1000-0526.2016.01.005
Abstract:
The improvement of the MIGFA technique is made based on the gust front echo features along the Yangtze River in Jiangsu detected by the Nanjing CINRAD/SA weather radar. Considering the smoothing algorithm and the low elevation data fusion, the 0.5° reflectivity echo thin line functional template is improved and the higher elevation echo thin line functional template is designed based on the gust front features. The original spatial difference reflectivity functional template is replaced by the double higher elevation reflectivity thin line functional templates. A group of the dynamicweighting functions is designed to combine the score array by the relationship of the gust front features and its distance from the station so as to effectively identify the gust front echo. Through the angle judgment and the echo flatness testing, the false alarm rate is further reduced. Finally, the effect of the identification is made by the gust front process seen on 14 June 2009 and detected with the Nanjing radar. And the effect of the evaluation is also made by 120 gust front samples in Nanjing radar. The results show that the critical success index is increased from 0.39 to 0.60 and the false alarm rate is reduced from 0.34 to 0.16 through the improving MIGFA.
The improvement of the MIGFA technique is made based on the gust front echo features along the Yangtze River in Jiangsu detected by the Nanjing CINRAD/SA weather radar. Considering the smoothing algorithm and the low elevation data fusion, the 0.5° reflectivity echo thin line functional template is improved and the higher elevation echo thin line functional template is designed based on the gust front features. The original spatial difference reflectivity functional template is replaced by the double higher elevation reflectivity thin line functional templates. A group of the dynamicweighting functions is designed to combine the score array by the relationship of the gust front features and its distance from the station so as to effectively identify the gust front echo. Through the angle judgment and the echo flatness testing, the false alarm rate is further reduced. Finally, the effect of the identification is made by the gust front process seen on 14 June 2009 and detected with the Nanjing radar. And the effect of the evaluation is also made by 120 gust front samples in Nanjing radar. The results show that the critical success index is increased from 0.39 to 0.60 and the false alarm rate is reduced from 0.34 to 0.16 through the improving MIGFA.
2016, 42(1):54-60.
DOI: 10.7519/j.issn.1000-0526.2016.01.006
Abstract:
Predicting urban electricity consumption is essential to electricity deployment of the electrical sector. An econometric model is established by using real monthly data from 2004 to 2012 to estimate the impact of weather on electricity consumption. Based on the model estimates, an online operation system of electricity consumption prediction has been initiated and tested for real application. The results show that: (1) There exists a robust and Ushaped relationship between temperature and electricity consumption. (2) The total electricity consumption peaks in winter, and the industrial electricity consumption decreases while the residential increases significantly due to the Spring Festival in February. (3) The simulated values fit quite well with the historical records and the predicted error is less than 5% demonstrating the capability of midlong term prediction. (4) The operation system, incorporated with weather forecasting data, help calculate continuous possible electricity demand of the next 12 months, which provides useful implications for electricity allocation and management.
Predicting urban electricity consumption is essential to electricity deployment of the electrical sector. An econometric model is established by using real monthly data from 2004 to 2012 to estimate the impact of weather on electricity consumption. Based on the model estimates, an online operation system of electricity consumption prediction has been initiated and tested for real application. The results show that: (1) There exists a robust and Ushaped relationship between temperature and electricity consumption. (2) The total electricity consumption peaks in winter, and the industrial electricity consumption decreases while the residential increases significantly due to the Spring Festival in February. (3) The simulated values fit quite well with the historical records and the predicted error is less than 5% demonstrating the capability of midlong term prediction. (4) The operation system, incorporated with weather forecasting data, help calculate continuous possible electricity demand of the next 12 months, which provides useful implications for electricity allocation and management.
2016, 42(1):61-66.
DOI: 10.7519/j.issn.1000-0526.2016.01.007
Abstract:
The aerosol optical thickness (AOD) in Guangdong Province from 2010 to 2013 was discussed based on the MERSI AOD products of Chinese Polar Orbiting Meteorological Satellite FY3A. It is found that the correlation coefficient between the MERSI AOD products and the groundbased sun photometer measured AOD data is 0.72. The mean absolute error and the root mean square error of the MERSI AOD are 0.12 and 0.15 respectively. So the MERSI AOD data meet the accuracy requirements of the paper. Spatially, a decreasing trend is found in order by Pearl River Delta Region, western region, eastern region and mountainous region. Among them, the mean AOD values are highest in Foshan City, Dongguan City and Zhongshan City, and lowest in Meizhou City and Heyuan City. Temporally, the AOD increases from 2010 to 2011 and then decreases from 2011 to 2013. What’s more, spring has the highest seasonal mean AOD, followed in order by summer, autumn and winter.
The aerosol optical thickness (AOD) in Guangdong Province from 2010 to 2013 was discussed based on the MERSI AOD products of Chinese Polar Orbiting Meteorological Satellite FY3A. It is found that the correlation coefficient between the MERSI AOD products and the groundbased sun photometer measured AOD data is 0.72. The mean absolute error and the root mean square error of the MERSI AOD are 0.12 and 0.15 respectively. So the MERSI AOD data meet the accuracy requirements of the paper. Spatially, a decreasing trend is found in order by Pearl River Delta Region, western region, eastern region and mountainous region. Among them, the mean AOD values are highest in Foshan City, Dongguan City and Zhongshan City, and lowest in Meizhou City and Heyuan City. Temporally, the AOD increases from 2010 to 2011 and then decreases from 2011 to 2013. What’s more, spring has the highest seasonal mean AOD, followed in order by summer, autumn and winter.
2016, 42(1):67-73.
DOI: 10.7519/j.issn.1000-0526.2016.01.008
Abstract:
Based on the statistical analysis of the CIND3830CC CINRAD data and surface observation data, the statistical characteristics of ‘V’ notch and the relationship between the ‘V’ notch and surface hail event at Pu’er observation during 2004-2013 are analyzed. The application of ‘V’ notch for hail early warning and the influence of ‘V’ notch for shortterm forecast are discussed as well. The results show that: (1) The best observation elevation ranges of the ‘V’ notch are from 0.5 to 2.4 degree elevation while the height that the ‘V’ notch occurs ranges from 2.1 to 6.5 km. (2) The ‘V’ notch can be divided into two types, the first one is at the radial back of massive echo cell while the second one is located in the radial back of schistose or massive echo multicells. (3) The composition reflectivity of typeⅠ ‘V’ notch ranges from 50 to 66 dBz, generally equal or greater than 55 dBz, with a hail occurrence probability of 69%. (4) The composite reflectivity of type Ⅱ ‘V’ notch ranges from 47 to 64 dBz, generally around 50 to 55 dBz, with a hail occurrence probability of 29%. (5) Hail event can be forecasted when the ‘V’ notch is observed and H45 dBz≥7.5 km, CR≥55 dBz with the rate of accuracy up to 100%. The early warning for ‘V’ notch is 5-102 min early. In addition, the identification method for hail echo in ‘V’ notch is studied.
Based on the statistical analysis of the CIND3830CC CINRAD data and surface observation data, the statistical characteristics of ‘V’ notch and the relationship between the ‘V’ notch and surface hail event at Pu’er observation during 2004-2013 are analyzed. The application of ‘V’ notch for hail early warning and the influence of ‘V’ notch for shortterm forecast are discussed as well. The results show that: (1) The best observation elevation ranges of the ‘V’ notch are from 0.5 to 2.4 degree elevation while the height that the ‘V’ notch occurs ranges from 2.1 to 6.5 km. (2) The ‘V’ notch can be divided into two types, the first one is at the radial back of massive echo cell while the second one is located in the radial back of schistose or massive echo multicells. (3) The composition reflectivity of typeⅠ ‘V’ notch ranges from 50 to 66 dBz, generally equal or greater than 55 dBz, with a hail occurrence probability of 69%. (4) The composite reflectivity of type Ⅱ ‘V’ notch ranges from 47 to 64 dBz, generally around 50 to 55 dBz, with a hail occurrence probability of 29%. (5) Hail event can be forecasted when the ‘V’ notch is observed and H45 dBz≥7.5 km, CR≥55 dBz with the rate of accuracy up to 100%. The early warning for ‘V’ notch is 5-102 min early. In addition, the identification method for hail echo in ‘V’ notch is studied.
2016, 42(1):74-79.
DOI: 10.7519/j.issn.1000-0526.2016.01.009
Abstract:
Two formulations (WMCIN001 and WMCIN002) of high efficient AgI pyrotechnics used in weather modification have been obtained after a number of screen tests were carried out in CAMS 1 m3 isothermal cloud chamber. The effectiveness can reach to 1014 g-1 AgI at temperatures of -7℃ and colder for WMCIN001, and it can reach up to 1015 g-1 AgI at -15℃. The foreign pyrotechnic was made according to the formulation of silverspare (USSR). The ice nucleating properties of silverspare and other five formulations of AgI pyrotechnics in the marketplace in 2011 was tested in the same chamber for comparison with the new pyrotechnics. The results show that the nucleating rates are very low for WMCIN001 and WMCIN002, and change less (in 40-55 min) in the temperature range between -7 and -20℃. The aerosol particles produced by WMCIN001 are identified by environmental scanning electron microscope (ESEM) and energy disperse spectroscopy (EDS). The particle sizes are within 0.02-0.60 μm in diameter, and the mean cuberoot diameter is 0.2472 μm. WMCIN001 aerosol has a pronounced bimodal size distribution with particles in the small diameter mode between 0.02-0.10 μm and particles constituting the mode between 0.20-0.55 μm. The relatively large particle size may be one cause for the low nucleating rates.
Two formulations (WMCIN001 and WMCIN002) of high efficient AgI pyrotechnics used in weather modification have been obtained after a number of screen tests were carried out in CAMS 1 m3 isothermal cloud chamber. The effectiveness can reach to 1014 g-1 AgI at temperatures of -7℃ and colder for WMCIN001, and it can reach up to 1015 g-1 AgI at -15℃. The foreign pyrotechnic was made according to the formulation of silverspare (USSR). The ice nucleating properties of silverspare and other five formulations of AgI pyrotechnics in the marketplace in 2011 was tested in the same chamber for comparison with the new pyrotechnics. The results show that the nucleating rates are very low for WMCIN001 and WMCIN002, and change less (in 40-55 min) in the temperature range between -7 and -20℃. The aerosol particles produced by WMCIN001 are identified by environmental scanning electron microscope (ESEM) and energy disperse spectroscopy (EDS). The particle sizes are within 0.02-0.60 μm in diameter, and the mean cuberoot diameter is 0.2472 μm. WMCIN001 aerosol has a pronounced bimodal size distribution with particles in the small diameter mode between 0.02-0.10 μm and particles constituting the mode between 0.20-0.55 μm. The relatively large particle size may be one cause for the low nucleating rates.
2016, 42(1):80-88.
DOI: 10.7519/j.issn.1000-0526.2016.01.010
Abstract:
Based on the requirement of objective identification and monitoring to key weather process, and the fact that the rainy season of Northeast China includes cold vertex precipitation, and using the daily precipitation data of 147 observing stations in Northeast China, this paper comprehensively analyzed the daily precipitation series disposed by 5 d moving average. Also, the contrast test of the daily moving average precipitation in the former years was designed. The threshold,duration as well as the criterion of onset and end dates cold vortex precipitation period in the Northeast China were confirmed. Then, based on the NCEP/NCAR daily reanalysis data of wind field and geopotential height field, the atmospheric circulation fields at different levels before, during and after the cold vortex precipitation period were analyzed, and the rationality of the criterion was validated. The objective identification method shows that the average onset date of the cold vortex r precipitation period in Northeast China is 26 May. The analysis of midsummer precipitation period reveals that the average end date of the cold vortex precipitation period is 25 June.
Based on the requirement of objective identification and monitoring to key weather process, and the fact that the rainy season of Northeast China includes cold vertex precipitation, and using the daily precipitation data of 147 observing stations in Northeast China, this paper comprehensively analyzed the daily precipitation series disposed by 5 d moving average. Also, the contrast test of the daily moving average precipitation in the former years was designed. The threshold,duration as well as the criterion of onset and end dates cold vortex precipitation period in the Northeast China were confirmed. Then, based on the NCEP/NCAR daily reanalysis data of wind field and geopotential height field, the atmospheric circulation fields at different levels before, during and after the cold vortex precipitation period were analyzed, and the rationality of the criterion was validated. The objective identification method shows that the average onset date of the cold vortex r precipitation period in Northeast China is 26 May. The analysis of midsummer precipitation period reveals that the average end date of the cold vortex precipitation period is 25 June.
2016, 42(1):89-96.
DOI: 10.7519/j.issn.1000-0526.2016.01.011
Abstract:
Based on affinity propagation clustering method, summer precipitation is regionalized over China. Summer precipitation in different regions serves as predicted objects, and preceding sea surface temperature and sea level pressure are selected to be predictors. By methods of image labeling algorithm, consecutive high correlation areas are extracted to determine the predictors. Least squares regression method is used to construct a model to predict summer precipitation in different regions. Different scoring methods including Ps, the anomaly sign sameness rate and anomaly correlation coefficient are used to validate the skills of prediction model in four different factor combination schemes. The results show that the model performs best when sea surface temperature and sea level pressure in winter and spring are together considered as factors. The averaged Ps score of cross validation is 81.4 from 1982 to 2009, with the anomaly sameness rate 63% and anomaly correlation coefficient 0.35. The retrospective forecast verification shows that the averaged scores from 2010 to 2014 are 77.1, 58% and 0.19, respectively. The reforecast skills are relatively stable every year, which means that the method has a good ability to predict summer precipitation in China. Moreover, it succeeds to predict the spatial characteristic of southern flood and northern drought in China in summer 2014.
Based on affinity propagation clustering method, summer precipitation is regionalized over China. Summer precipitation in different regions serves as predicted objects, and preceding sea surface temperature and sea level pressure are selected to be predictors. By methods of image labeling algorithm, consecutive high correlation areas are extracted to determine the predictors. Least squares regression method is used to construct a model to predict summer precipitation in different regions. Different scoring methods including Ps, the anomaly sign sameness rate and anomaly correlation coefficient are used to validate the skills of prediction model in four different factor combination schemes. The results show that the model performs best when sea surface temperature and sea level pressure in winter and spring are together considered as factors. The averaged Ps score of cross validation is 81.4 from 1982 to 2009, with the anomaly sameness rate 63% and anomaly correlation coefficient 0.35. The retrospective forecast verification shows that the averaged scores from 2010 to 2014 are 77.1, 58% and 0.19, respectively. The reforecast skills are relatively stable every year, which means that the method has a good ability to predict summer precipitation in China. Moreover, it succeeds to predict the spatial characteristic of southern flood and northern drought in China in summer 2014.
2016, 42(1):97-106.
DOI: 10.7519/j.issn.1000-0526.2016.01.012
Abstract:
The 28year hindcast experiments (1983-2010) and the 2013 summer prediction are performed by using regional climate model (RegCM3) which is embedded in the global atmosphere ocean coupled model (BCC_CM1.0) whose climatological means are adjusted based on the NCEPR2 reanalysis datasets. A traditional dynamical downscaling (TDD) parallel run by using RegCM3 that is driven by original BCC_CM1.0 output is also conducted. The results indicate that after using GCM (Global Climate Model) bias corrected method, the capability of hindcasting multiyear mean summer temperature and precipitation is greatly improved. Compared to TDD approach, although the predictability of temperature anomaly in northeastern China declines, the prediction of summer extreme heat event over the central part of Eastern China in 2013 is remarkably enhanced. The enhanced performance of hindcasting multiyear averaged Western Pacific subtropical high (WPSH) mainly leads to the improvement of predicting summer extreme heat event in 2013.
The 28year hindcast experiments (1983-2010) and the 2013 summer prediction are performed by using regional climate model (RegCM3) which is embedded in the global atmosphere ocean coupled model (BCC_CM1.0) whose climatological means are adjusted based on the NCEPR2 reanalysis datasets. A traditional dynamical downscaling (TDD) parallel run by using RegCM3 that is driven by original BCC_CM1.0 output is also conducted. The results indicate that after using GCM (Global Climate Model) bias corrected method, the capability of hindcasting multiyear mean summer temperature and precipitation is greatly improved. Compared to TDD approach, although the predictability of temperature anomaly in northeastern China declines, the prediction of summer extreme heat event over the central part of Eastern China in 2013 is remarkably enhanced. The enhanced performance of hindcasting multiyear averaged Western Pacific subtropical high (WPSH) mainly leads to the improvement of predicting summer extreme heat event in 2013.
2016, 42(1):107-114.
DOI: 10.7519/j.issn.1000-0526.2016.01.013
Abstract:
Focusing on the need that the reflectivity data estimated by wind profile radar should be validated comparison experiment of the reflectivities of wind profile radar (WPR) and the raindrop disdrometer was carried out. Through the comparison of the detection data from the two kinds of detection equipments the reliability and usability of the wind profiler radar reflectivity is tested. The results show that the contrast method between the reflectivity of the low mode 360-1440 m of the wind profile radar and the reflectivity of 3 min raindrop disdrometer is determined to reduce the temporal and spatial differences in maximum extent. When the raindrop disdrometer reflectivity is less than 40 dBz, the wind profile radar reflectivity data are reliable and available. At the same time, the limited dynamic range of the wind profile radar causes the phenomenon of underestimated reflectivity so that the application of the wind profile radar reflectivity is limited somewhat in the atmospheric vertical structure and microphysical properties and so on.
Focusing on the need that the reflectivity data estimated by wind profile radar should be validated comparison experiment of the reflectivities of wind profile radar (WPR) and the raindrop disdrometer was carried out. Through the comparison of the detection data from the two kinds of detection equipments the reliability and usability of the wind profiler radar reflectivity is tested. The results show that the contrast method between the reflectivity of the low mode 360-1440 m of the wind profile radar and the reflectivity of 3 min raindrop disdrometer is determined to reduce the temporal and spatial differences in maximum extent. When the raindrop disdrometer reflectivity is less than 40 dBz, the wind profile radar reflectivity data are reliable and available. At the same time, the limited dynamic range of the wind profile radar causes the phenomenon of underestimated reflectivity so that the application of the wind profile radar reflectivity is limited somewhat in the atmospheric vertical structure and microphysical properties and so on.
2016, 42(1):115-121.
DOI: 10.7519/j.issn.1000-0526.2016.01.014
Abstract:
In summer 2015, the mean precipitation over China was 297.6 mm, which is less than normal by 8.5%. The spatial distribution of precipitation anomalies showed the northless and southmore pattern, and precipitation over the middle and lower reaches of Yangtze River and the YangtzeHuaihe River Valley was significantly more than normal. The Meiyu rainy season lasted longer with more rainfall than normal. Further study indicated that positive Indian Ocean basinwide mode (IOBW) has been enhanced since May 2015, triggering a local zonal circulation with upward flow in the west and downward motion in the east. This circulation is favorable for the establishment of a strong and westward Northwest Pacific subtropical high, resulting in high frequency of strong southwest lowlevel jet in the southeast of China. The lowlevel jet transported water vapor from the South China Sea to the YangzeHuai River Valley and released unstable energy, and such combined condition is useful for the development of convection and the occurrence of precipitation, extending the Meiyu season and increasing the amount of rainfall.
In summer 2015, the mean precipitation over China was 297.6 mm, which is less than normal by 8.5%. The spatial distribution of precipitation anomalies showed the northless and southmore pattern, and precipitation over the middle and lower reaches of Yangtze River and the YangtzeHuaihe River Valley was significantly more than normal. The Meiyu rainy season lasted longer with more rainfall than normal. Further study indicated that positive Indian Ocean basinwide mode (IOBW) has been enhanced since May 2015, triggering a local zonal circulation with upward flow in the west and downward motion in the east. This circulation is favorable for the establishment of a strong and westward Northwest Pacific subtropical high, resulting in high frequency of strong southwest lowlevel jet in the southeast of China. The lowlevel jet transported water vapor from the South China Sea to the YangzeHuai River Valley and released unstable energy, and such combined condition is useful for the development of convection and the occurrence of precipitation, extending the Meiyu season and increasing the amount of rainfall.
2016, 42(1):122-128.
DOI: 10.7519/j.issn.1000-0526.2016.01.015
Abstract:
The main characteristics of the general atmospheric circulation in October 2015 are as follows: Over the Northern Hemisphere, there was one polar vortex center, which is more intense than usual. In the midhigh latitudes,the circulation presented a fourwave pattern. The West Pacific subtropic high system was stronger than usual, and its ridge extended to west obviously. The monthly mean precipitation was 39.5 mm, 10.3% higher than the climatological mean (35.8 mm). Meanwhile, the monthly mean temperature was 11.0℃, which is 0.7℃ higher than its climatological mean (10.3℃). In the Northeast, the Beijing-Tianjin-Hebei Region and the east of Northwest, 62 stations observed extrem temperature drop events. Four severe rainfall processes occurred during this month. The central and western part of Guangdong, and the east part of Guangxi went through a torrential rain process from 3 to 6 October. During this month, four cold air processes affected China. Central and eastern China suffered from three severe fog and haze events. On 4 October, Severe Typhoon “Mujigae” made landfall in Guangdong with intensity equal to the historic record, causing great losses.
The main characteristics of the general atmospheric circulation in October 2015 are as follows: Over the Northern Hemisphere, there was one polar vortex center, which is more intense than usual. In the midhigh latitudes,the circulation presented a fourwave pattern. The West Pacific subtropic high system was stronger than usual, and its ridge extended to west obviously. The monthly mean precipitation was 39.5 mm, 10.3% higher than the climatological mean (35.8 mm). Meanwhile, the monthly mean temperature was 11.0℃, which is 0.7℃ higher than its climatological mean (10.3℃). In the Northeast, the Beijing-Tianjin-Hebei Region and the east of Northwest, 62 stations observed extrem temperature drop events. Four severe rainfall processes occurred during this month. The central and western part of Guangdong, and the east part of Guangxi went through a torrential rain process from 3 to 6 October. During this month, four cold air processes affected China. Central and eastern China suffered from three severe fog and haze events. On 4 October, Severe Typhoon “Mujigae” made landfall in Guangdong with intensity equal to the historic record, causing great losses.
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ISSN:1000-0526 CN:11-2282/P