ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 32,Issue 5,2006 Table of Contents
2006, 32(5):3-9.
DOI: 10.7519/j.issn.1000-0526.2006.5.001
Abstract:
In order to find the effect of the upper-level jet on tropical cyclones (TCs), ten landing tropical cyclones from the Yellow Sea or the Bohai Sea are divided into the northern-moving pattern and northeastern-moving pattern, and a set of composite analyses based on the data of ECMWF are conducted. The result shows that the TCs actually tend to move in the right side of the upper-level jets, and tend to be approaching up to the entrance of the maximum wind speed zones of the jets. In addition, when TCs approached to the jets, the lower-level motions around the TCs appeared a second-order maximum speed center of horizontal wind components and a centrifugal growth of convection in consequence. The upward motion caused by the divergence linked to the upper-level jet is regarded as the main reason of the changes of the horizontal and vertical motions of the TCs.
In order to find the effect of the upper-level jet on tropical cyclones (TCs), ten landing tropical cyclones from the Yellow Sea or the Bohai Sea are divided into the northern-moving pattern and northeastern-moving pattern, and a set of composite analyses based on the data of ECMWF are conducted. The result shows that the TCs actually tend to move in the right side of the upper-level jets, and tend to be approaching up to the entrance of the maximum wind speed zones of the jets. In addition, when TCs approached to the jets, the lower-level motions around the TCs appeared a second-order maximum speed center of horizontal wind components and a centrifugal growth of convection in consequence. The upward motion caused by the divergence linked to the upper-level jet is regarded as the main reason of the changes of the horizontal and vertical motions of the TCs.
2006, 32(5):10-15.
DOI: 10.7519/j.issn.1000-0526.2006.5.002
Abstract:
The moist air current crossing over the higher mountains and the forming of the reversal flow at the lower layer in the lee of the mountain are investigated with the advanced regional prediction system (ARPS). The results show that the trend and elevation of the mountain range are the most important factors in the influence of terrains on weather and climate, and the mountain plays a positive role in the reversal flow weather. The effects of moisture are apparent on the forming of the blocked reversal flow in the upslope and the reversal flow in the lee of the mountain. It is suggested that the precipitation mechanism should include the lee precipitation mechanism for the lee reversal flow, except the upslope precipitation, especially for the moist airflow over higher mountain.
The moist air current crossing over the higher mountains and the forming of the reversal flow at the lower layer in the lee of the mountain are investigated with the advanced regional prediction system (ARPS). The results show that the trend and elevation of the mountain range are the most important factors in the influence of terrains on weather and climate, and the mountain plays a positive role in the reversal flow weather. The effects of moisture are apparent on the forming of the blocked reversal flow in the upslope and the reversal flow in the lee of the mountain. It is suggested that the precipitation mechanism should include the lee precipitation mechanism for the lee reversal flow, except the upslope precipitation, especially for the moist airflow over higher mountain.
2006, 32(5):16-21.
DOI: 10.7519/j.issn.1000-0526.2006.05.003
Abstract:
In the nesting model, the initial field is from the forecast field by the Mesoscale Analysis and Process System (MAPS) Model, which indicated the status of stratified atmosphere over 77 counties in Hubei Province. In the one- dimension cumulus model, the disturbance parameters are determined by the analysis of synoptic pattern. The non-catalyzed/catalyzed precipitation can be simulated with the nesting model, and the catalyzing potential of cumulus of the 77sites is obtained respectively.
In the nesting model, the initial field is from the forecast field by the Mesoscale Analysis and Process System (MAPS) Model, which indicated the status of stratified atmosphere over 77 counties in Hubei Province. In the one- dimension cumulus model, the disturbance parameters are determined by the analysis of synoptic pattern. The non-catalyzed/catalyzed precipitation can be simulated with the nesting model, and the catalyzing potential of cumulus of the 77sites is obtained respectively.
2006, 32(5):22-28.
DOI: 10.7519/j.issn.1000-0526.2006.5.004
Abstract:
The climate variation of the Zhalong Wetland and its accommodation effect on the small area are investigated with four ways of climate analysis (for example, Mann-Kendall method) based on the monthly maximum and minimum temperature data in 4 representative stations in Zhalong Wetland. An analysis of the variations of mean monthly, seasonal and annual maximum and minimum temperature is made. The results show that the maximum and minimum temperature exist an obvious asymmetry variation and obvious anti-variations at some stages. Additionally, the change of minimum temperature has its climate sudden change characteristic. Based on R/S analysis of the maximum and minimum temperature,the variations of the maximum and minimum temperature had evident Hurst phenomena.In the area, the climate warming tends to be slow.
The climate variation of the Zhalong Wetland and its accommodation effect on the small area are investigated with four ways of climate analysis (for example, Mann-Kendall method) based on the monthly maximum and minimum temperature data in 4 representative stations in Zhalong Wetland. An analysis of the variations of mean monthly, seasonal and annual maximum and minimum temperature is made. The results show that the maximum and minimum temperature exist an obvious asymmetry variation and obvious anti-variations at some stages. Additionally, the change of minimum temperature has its climate sudden change characteristic. Based on R/S analysis of the maximum and minimum temperature,the variations of the maximum and minimum temperature had evident Hurst phenomena.In the area, the climate warming tends to be slow.
2006, 32(5):29-34.
DOI: 10.7519/j.issn.1000-0526.2006.5.005
Abstract:
Based on the sounding data at Huaihua and Changsha weather stations, Hunan Province from 1994 to 2003, the cloud water vapor content in the vertical atmosphere columniation are analyzed and computed over Zhexi reservoir and drainage area of Hunan province. It shows that the annual average value of cloud water vapor content is 3.62g·cm-2 and varies with the synoptic pattern in Zhexi reservoir and drainage area. The cloud system water vapor content value near the outer edges of the typhoon is 6.01g·cm-2, greater than other cloud. Average exchange times of water vapor content is 3.04 times per month in vertical atmosphere columniation and updating ratio of water vapor is 9.92 days. Average net water vapor content into the atmosphere in Zhexi drainage area in one year is 23487 million m3. It is possible that precipitation enhancement gross value would be about 2984.3 million m3,if all potential clouds in the sky in this area are seeded.
Based on the sounding data at Huaihua and Changsha weather stations, Hunan Province from 1994 to 2003, the cloud water vapor content in the vertical atmosphere columniation are analyzed and computed over Zhexi reservoir and drainage area of Hunan province. It shows that the annual average value of cloud water vapor content is 3.62g·cm-2 and varies with the synoptic pattern in Zhexi reservoir and drainage area. The cloud system water vapor content value near the outer edges of the typhoon is 6.01g·cm-2, greater than other cloud. Average exchange times of water vapor content is 3.04 times per month in vertical atmosphere columniation and updating ratio of water vapor is 9.92 days. Average net water vapor content into the atmosphere in Zhexi drainage area in one year is 23487 million m3. It is possible that precipitation enhancement gross value would be about 2984.3 million m3,if all potential clouds in the sky in this area are seeded.
2006, 32(5):35-40.
DOI: 10.7519/j.issn.1000-0526.2006.05.006
Abstract:
Based on the comparative test data from February to July in 2005, the difference of air temperature / relative humidity measured inside the thermometer screen of glass fiber reinforced plastic and that of timber are analyzed. In the meantime, the difference of response speed to air temperature as well as relative humidity changes in the two kinds of screens is analyzed. The impact of various cloud cover and various wind velocity on the difference of air temperature measured inside the two screens is discussed. The result indicates that the mean difference of air temperature inside the two kinds of screens is within 0.1℃, the standard deviation of the difference is within 0.2℃. The mean difference of relative humidity inside the two kinds of screens is within 0.4%, the standard deviation of the difference is within 2.1%. The response to air temperature / relative humidity inside the thermometer screen of glass fiber reinforced plastic is almost faster than that in the screen of timber. No matter under what cloud cover or what wind velocity, the mean difference of air temperature in the two kinds of screens is almost within 0.1℃.
Based on the comparative test data from February to July in 2005, the difference of air temperature / relative humidity measured inside the thermometer screen of glass fiber reinforced plastic and that of timber are analyzed. In the meantime, the difference of response speed to air temperature as well as relative humidity changes in the two kinds of screens is analyzed. The impact of various cloud cover and various wind velocity on the difference of air temperature measured inside the two screens is discussed. The result indicates that the mean difference of air temperature inside the two kinds of screens is within 0.1℃, the standard deviation of the difference is within 0.2℃. The mean difference of relative humidity inside the two kinds of screens is within 0.4%, the standard deviation of the difference is within 2.1%. The response to air temperature / relative humidity inside the thermometer screen of glass fiber reinforced plastic is almost faster than that in the screen of timber. No matter under what cloud cover or what wind velocity, the mean difference of air temperature in the two kinds of screens is almost within 0.1℃.
2006, 32(5):41-45.
DOI: 10.7519/j.issn.1000-0526.2006.5.007
Abstract:
By using of the wavelet analysis method, the variation characteristics and its time-frequency characteristics of spring precipitation in the Qinghai Plateau are studied with the spring precipitation data from 1961 to 2003 at 38 weather stations. The results show that the spring precipitation appeared an increase trend, especially in Qinghai region. In 10 years time scales, the characteristics of dry/wet vicissitude is very significant. There are 6 dry/wet vicissitude period in the recent 43 years. In 4 periods of 1961—1962, 1980—1982, 1994—1996, 1999—2000, negative phases appear in the most cycles. The same phase superimposition of the various oscillation cause heavy drought stage in spring.
By using of the wavelet analysis method, the variation characteristics and its time-frequency characteristics of spring precipitation in the Qinghai Plateau are studied with the spring precipitation data from 1961 to 2003 at 38 weather stations. The results show that the spring precipitation appeared an increase trend, especially in Qinghai region. In 10 years time scales, the characteristics of dry/wet vicissitude is very significant. There are 6 dry/wet vicissitude period in the recent 43 years. In 4 periods of 1961—1962, 1980—1982, 1994—1996, 1999—2000, negative phases appear in the most cycles. The same phase superimposition of the various oscillation cause heavy drought stage in spring.
2006, 32(5):46-51.
DOI: 10.7519/j.issn.1000-0526.2006.05.008
Abstract:
The AgI seeding experiments using seeding aircraft were carried out to enhance precipitation at the upriver catchments of the Miyun reservoir from June 2004 to July 2005. According to the regular and continuous measurements at two sampling spots located at the entrance of the Bai River and the reservoir, the effects of seeding precipitation on Ag+ and other chemical compositions of the water in the Miyun reservoir are studied. It is shown that the constituent concentrations of the water in the reservoir during the seeding period are lower than those during non-seeding period. There is obvious monthly change of the Ag+ concentration. It shows that the minimum occurred during seeding period and the maximum during non-seeding period. The results suggest that the enhancing precipitation by seeding does not effect the Ag+ concentration in the Miyun reservoir.
The AgI seeding experiments using seeding aircraft were carried out to enhance precipitation at the upriver catchments of the Miyun reservoir from June 2004 to July 2005. According to the regular and continuous measurements at two sampling spots located at the entrance of the Bai River and the reservoir, the effects of seeding precipitation on Ag+ and other chemical compositions of the water in the Miyun reservoir are studied. It is shown that the constituent concentrations of the water in the reservoir during the seeding period are lower than those during non-seeding period. There is obvious monthly change of the Ag+ concentration. It shows that the minimum occurred during seeding period and the maximum during non-seeding period. The results suggest that the enhancing precipitation by seeding does not effect the Ag+ concentration in the Miyun reservoir.
2006, 32(5):52-56.
DOI: 10.7519/j.issn.1000-0526.2006.05.009
Abstract:
Based on the echo data of the Yichang WSR-98D S- band Doppler weather radar, a severe storm with 28.8 m·s -1 maximum instantaneous wind speed at the Three Gorge Dam Area on 2 July 2001 is analyzed. The result shows that, under the condition of environmental southerly airflow field, there was a meso-scale convergence line on the southern slop of the Shennongjia Mountain, the convective clouds developed near the convergence line, then moved northeastward along the eastern slop of the Shennongjia Mountain, and affected the Three Gorge Dam Area. It suggests that the upwind airflow surge at the southern slop of the Shennongjia Mountain triggered and maintained the severe storm in some degree.
Based on the echo data of the Yichang WSR-98D S- band Doppler weather radar, a severe storm with 28.8 m·s -1 maximum instantaneous wind speed at the Three Gorge Dam Area on 2 July 2001 is analyzed. The result shows that, under the condition of environmental southerly airflow field, there was a meso-scale convergence line on the southern slop of the Shennongjia Mountain, the convective clouds developed near the convergence line, then moved northeastward along the eastern slop of the Shennongjia Mountain, and affected the Three Gorge Dam Area. It suggests that the upwind airflow surge at the southern slop of the Shennongjia Mountain triggered and maintained the severe storm in some degree.
2006, 32(5):57-61.
DOI: 10.7519/j.issn.1000-0526.2006.5.010
Abstract:
The support vector machine (SVM), a new general machinery study method based on the frame of statistical study theory, may solve the problems of non-linear classification and regression in sample space and be a effective method of processing the non-liner classification and regression. The complexity and non-linearity of factors of climate change decide the non-linear relationship between the forecast factors and the forecast object, and the SVM provide an effective and feasible way to forecast short-term climate. A SVM non-linear classification model of positive/ negative departure in summer precipitation is developed according to the 15 forecast factors, including the sea surface temperature of Nino area, the southern Oscillation index, the subtropical high area index and the polar vortex area index of Asian region, meanwhile, a SVM regression model of summer precipitation in Yangquan is developed as well.
The support vector machine (SVM), a new general machinery study method based on the frame of statistical study theory, may solve the problems of non-linear classification and regression in sample space and be a effective method of processing the non-liner classification and regression. The complexity and non-linearity of factors of climate change decide the non-linear relationship between the forecast factors and the forecast object, and the SVM provide an effective and feasible way to forecast short-term climate. A SVM non-linear classification model of positive/ negative departure in summer precipitation is developed according to the 15 forecast factors, including the sea surface temperature of Nino area, the southern Oscillation index, the subtropical high area index and the polar vortex area index of Asian region, meanwhile, a SVM regression model of summer precipitation in Yangquan is developed as well.
2006, 32(5):62-66.
DOI: 10.7519/j.issn.1000-0526.2006.5.011
Abstract:
Based on observational data of 146 meteorological stations around the Yellow River basin from 1960 to 2000, the spatial and temporal distributions of the sunshine percentage are studied. The result shows that the sunshine percentage in the Yellow River basin has steadily decreased on average, especially in summer and winter. Compared with the 1960s, the sunshine percentage of 1990s decreased in the middle and lower reaches of the Yellow River, and increased a little in the upper reach.
Based on observational data of 146 meteorological stations around the Yellow River basin from 1960 to 2000, the spatial and temporal distributions of the sunshine percentage are studied. The result shows that the sunshine percentage in the Yellow River basin has steadily decreased on average, especially in summer and winter. Compared with the 1960s, the sunshine percentage of 1990s decreased in the middle and lower reaches of the Yellow River, and increased a little in the upper reach.
2006, 32(5):67-73.
DOI: 10.7519/j.issn.1000-0526.2006.5.012
Abstract:
According to statistics, there are 17 heavy rain cases happened in the south of Zhejiang Province in May—June of 1960—2002. Using NCEP reanalysis data, the synoptic situations of 17 cases are analyzed, and are divided into some synoptic patterns. Its physical characters, including Q-vectors, are also calculated. The relationship between rainstorms and Q-vectors is discussed in detail. The results show that the patterns of heavy rain primary based on temperature are concise and practical. The convergence of Q-vectors and rainstorms are well homologous,the center of rainstorm caused by non-thermal depression situated in the convergence center of Q-vectors or south to southwestern of the convergence center of Q-vectors. It has good effect for rainstorm forecast in May—June of 2005.
According to statistics, there are 17 heavy rain cases happened in the south of Zhejiang Province in May—June of 1960—2002. Using NCEP reanalysis data, the synoptic situations of 17 cases are analyzed, and are divided into some synoptic patterns. Its physical characters, including Q-vectors, are also calculated. The relationship between rainstorms and Q-vectors is discussed in detail. The results show that the patterns of heavy rain primary based on temperature are concise and practical. The convergence of Q-vectors and rainstorms are well homologous,the center of rainstorm caused by non-thermal depression situated in the convergence center of Q-vectors or south to southwestern of the convergence center of Q-vectors. It has good effect for rainstorm forecast in May—June of 2005.
2006, 32(5):74-79.
DOI: 10.7519/j.issn.1000-0526.2006.5.013
Abstract:
Based on the routine and non-conventional data, mesoscale convective systems and backgrounds causing heavy rain in Sichuan and Chongqing during 3—6 September 2004 are analyzed. It is found that (1) the reason for heavy rainfall is meso-β scale convective systems, occurred and developing frequently on the low vortex and shear line, with local and explosive features occurred and developed in the Sichuan Province and Chongqing City; (2) the lower-level convergence and upper-level divergence and vertical ascent motion probably provided the suitable dynamic environment for the generation and development of the mesoscale convective system; and (3) strong convergence of water vapor flux and the conditional convective instability in the lower troposphere probably provided the suitable thermodynamic environment for the generation and development of the mesoscale convective system.
Based on the routine and non-conventional data, mesoscale convective systems and backgrounds causing heavy rain in Sichuan and Chongqing during 3—6 September 2004 are analyzed. It is found that (1) the reason for heavy rainfall is meso-β scale convective systems, occurred and developing frequently on the low vortex and shear line, with local and explosive features occurred and developed in the Sichuan Province and Chongqing City; (2) the lower-level convergence and upper-level divergence and vertical ascent motion probably provided the suitable dynamic environment for the generation and development of the mesoscale convective system; and (3) strong convergence of water vapor flux and the conditional convective instability in the lower troposphere probably provided the suitable thermodynamic environment for the generation and development of the mesoscale convective system.
2006, 32(5):80-86.
DOI: 10.7519/j.issn.1000-0526.2006.5.014
Abstract:
By using of the routine sounding, surface observation data and analysis of satellite image, two abrupt rainstorm in Xi’an are analyzed. It shows that the cause of rainstorm is the effect of the easterlies wind jet along the north side of typhoon and the low-system of the westerly belt in the middle latitude, the main vapor and energy pathway is the jet of the easterly belt along the north side of typhoon low- pressure circulation, the meso-β scale convective system (MβCS) bring on development and maintain of abrupt rainstorm.
By using of the routine sounding, surface observation data and analysis of satellite image, two abrupt rainstorm in Xi’an are analyzed. It shows that the cause of rainstorm is the effect of the easterlies wind jet along the north side of typhoon and the low-system of the westerly belt in the middle latitude, the main vapor and energy pathway is the jet of the easterly belt along the north side of typhoon low- pressure circulation, the meso-β scale convective system (MβCS) bring on development and maintain of abrupt rainstorm.
2006, 32(5):87-93.
DOI: 10.7519/j.issn.1000-0526.2006.5.015
Abstract:
Based on meteorological observational data and mesoscale numerical model products, the physical mechanism of a heavy rain is analyzed. The analysis shows that sustaining meridional circulation at upper levels, low level warm shear line and jets, the strengthening of Southwest vortex and the obstruction from the high pressure on Japanese sea are the important reasons of the heavy rain. The main mechanisms are long-time transfer of vapor and energy by various jet streams, and the coupling among the strong vorticity column, violent convergence ascending motion and saturated air column.
Based on meteorological observational data and mesoscale numerical model products, the physical mechanism of a heavy rain is analyzed. The analysis shows that sustaining meridional circulation at upper levels, low level warm shear line and jets, the strengthening of Southwest vortex and the obstruction from the high pressure on Japanese sea are the important reasons of the heavy rain. The main mechanisms are long-time transfer of vapor and energy by various jet streams, and the coupling among the strong vorticity column, violent convergence ascending motion and saturated air column.
2006, 32(5):94-98.
DOI: 10.7519/j.issn.1000-0526.2006.5.016
Abstract:
A rainy process in spring in 2005 in Jilin Province is analyzed based on its large-scale circulation and physical factors, especially the wind data of automatic weather stations. The result shows that the mid-scale shear line ensured by the wind data of automatic weather stations has some relationship with the region, the intensity and the happening time of rainfall, and the geographic effect plays an important role in the appearance of the mid-scale shear line.
A rainy process in spring in 2005 in Jilin Province is analyzed based on its large-scale circulation and physical factors, especially the wind data of automatic weather stations. The result shows that the mid-scale shear line ensured by the wind data of automatic weather stations has some relationship with the region, the intensity and the happening time of rainfall, and the geographic effect plays an important role in the appearance of the mid-scale shear line.
2006, 32(5):99-104.
DOI: 10.7519/j.issn.1000-0526.2006.5.017
Abstract:
The monthly mean temperature, precipitation, mean maximum and minimum temperature, first/latest frost, frost-free season, accumulated temperature and soaking rain in four weather stations of Tieling during 1960—2004 are analyzed by using of linear trend analysis and moving mean methods. The results show that the temperature has an obvious warm tendency and the precipitation has a decrease tendency in Tieling during recent 45 years. Specifically, in recent 15 years, the rising range of temperature increases, and precipitation reduces obviously in spring and summer. There is also an evident difference in the changes in four seasons. The warm trend is evident in winter, the rising range of the mean minimum temperature is more evident than the mean maximum temperature, and the daily range of temperature decreases. The first frost is delayed, the latest frost is ahead, as a result, the frost-free period prolongs, and the accumulated temperature obviously increases, the late soaking rain and the extreme climate events occur frequently.
The monthly mean temperature, precipitation, mean maximum and minimum temperature, first/latest frost, frost-free season, accumulated temperature and soaking rain in four weather stations of Tieling during 1960—2004 are analyzed by using of linear trend analysis and moving mean methods. The results show that the temperature has an obvious warm tendency and the precipitation has a decrease tendency in Tieling during recent 45 years. Specifically, in recent 15 years, the rising range of temperature increases, and precipitation reduces obviously in spring and summer. There is also an evident difference in the changes in four seasons. The warm trend is evident in winter, the rising range of the mean minimum temperature is more evident than the mean maximum temperature, and the daily range of temperature decreases. The first frost is delayed, the latest frost is ahead, as a result, the frost-free period prolongs, and the accumulated temperature obviously increases, the late soaking rain and the extreme climate events occur frequently.
2006, 32(5):105-109.
DOI: 10.7519/j.issn.1000-0526.2006.5.018
Abstract:
The Flood-Causing Torrential Rain forecasting and warning system for Huaihe River and it′s method are introduced. Rainfall was estimated by using of satellite and CINRAD-radar data.. Furthermore, form GMS-5 Multi-Channel data, we developed the empirical formula of rainfall measurement using statistic method in Huaihe River field. And then, combining the HLAFS data, Flood-Causing Torrential Rain were forecasted and warned. The system was tested by the application of flood season in 2003 and good service effect was received.
The Flood-Causing Torrential Rain forecasting and warning system for Huaihe River and it′s method are introduced. Rainfall was estimated by using of satellite and CINRAD-radar data.. Furthermore, form GMS-5 Multi-Channel data, we developed the empirical formula of rainfall measurement using statistic method in Huaihe River field. And then, combining the HLAFS data, Flood-Causing Torrential Rain were forecasted and warned. The system was tested by the application of flood season in 2003 and good service effect was received.
2006, 32(5):110-115.
DOI: 10.7519/j.issn.1000-0526.2006.5.019
Abstract:
By individual and composite analysis way, the allocation and variation regularity of various level synoptic systems and convective cloud clusters over the Bay of Bengal before Guangxi heavy rain are investigated based on NCEP and TBB data. The characteristics of the developing convective cloud clusters and the increasing meridional wind over the Bay of Bengal are found. A mid-range forecast system of the summer monsoon heavy rain in Guangxi is developed.
By individual and composite analysis way, the allocation and variation regularity of various level synoptic systems and convective cloud clusters over the Bay of Bengal before Guangxi heavy rain are investigated based on NCEP and TBB data. The characteristics of the developing convective cloud clusters and the increasing meridional wind over the Bay of Bengal are found. A mid-range forecast system of the summer monsoon heavy rain in Guangxi is developed.
2006, 32(5):116-120.
DOI: 10.7519/j.issn.1000-0526.2006.5.020
Abstract:
By the parallelism investigation of the growth condition of tobacco and weather factors in various elevation heights, the correlation analysis is made. It is shown that in the various growth stages tobacco leaves request different sunshine duration. With quadratic curve, the variation of the sunshine duration with the elevation height is simulated. The most suitable time period and the elevation height for the fine quality of tobacco leaves growth are put forward.
By the parallelism investigation of the growth condition of tobacco and weather factors in various elevation heights, the correlation analysis is made. It is shown that in the various growth stages tobacco leaves request different sunshine duration. With quadratic curve, the variation of the sunshine duration with the elevation height is simulated. The most suitable time period and the elevation height for the fine quality of tobacco leaves growth are put forward.
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ISSN:1000-0526 CN:11-2282/P