ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 34,Issue 10,2008 Table of Contents
2008, 34(10):3-11.
DOI: 10.7519/j.issn.1000-0526.2008.10.001
Abstract:
A method of forecasting rainfall based on numerical prediction products is prese nted. According to the idea of artificial intelligence classification and integr ation, numerical prediction products of T213, Japanese and German models are int egrated together by using the BackPropagation neural network, and it will cont ribute advantages of various means and form an integrated forecast system. On th is basis, selforganizing neural network is used to classify the weather type a ccording to the situation of height field and temperature and humidity on the su rface layer in forecasting area. Then different forecast elements are selected a nd different forecast models are established for different weather types. Using the method mentioned above, the forecast model is built by using the data from M ay to September in 2003 to 2005, and is tested by forecasting rain fall from May to September in 2006 to 2007 at 68 stations in the ChangjiangHua ihe River basin. The result shows that the method is quite practicable.
A method of forecasting rainfall based on numerical prediction products is prese nted. According to the idea of artificial intelligence classification and integr ation, numerical prediction products of T213, Japanese and German models are int egrated together by using the BackPropagation neural network, and it will cont ribute advantages of various means and form an integrated forecast system. On th is basis, selforganizing neural network is used to classify the weather type a ccording to the situation of height field and temperature and humidity on the su rface layer in forecasting area. Then different forecast elements are selected a nd different forecast models are established for different weather types. Using the method mentioned above, the forecast model is built by using the data from M ay to September in 2003 to 2005, and is tested by forecasting rain fall from May to September in 2006 to 2007 at 68 stations in the ChangjiangHua ihe River basin. The result shows that the method is quite practicable.
2 Analysis on Micro Scale Horizontal Gradient of Meteorological Elements in Disa
strous Weather Cases
2008, 34(10):12-19.
DOI: 10.7519/j.issn.1000-0526.2008.10.002
Abstract:
The data obtained at both ends of runway at Shenzhen airport is used to analyze the micro scale horizontal gradient variation, and four typical disastrous weath er cases were chosen to do the detail analysis. It was found that the annual mea n horizontal gradients of pressure, temperature and wind speed are 0.0064hPa/km, 0.035℃/km and 1.1×10-4/s, respectively. In the case of a squall, the l ongitudinal horizontal gradients of pressure, temperature and wind speed are 1.2 hPa/km, 0.035℃/km and 5.3×10-3/s, respectively and the minus horizontal gradient of temperature and relative humidity maintained over 45 minutes until the squall reached. In the case of thunderstorm the horizontal gradient of each element is similar to the case of squall, but no minus horizontal gradient of relative humidity occurred. In the case of continuous heavy rain, the 0.15hPa/km pressure gradient and 0.5℃ /km temperature gradient and 90° wind direction difference were maintained over 10 hours. When a cold air arrived, the temperature and pressure gradient would reverse, but relative humidity gradient would keep invariable, and the gradients would last until the end of process.
The data obtained at both ends of runway at Shenzhen airport is used to analyze the micro scale horizontal gradient variation, and four typical disastrous weath er cases were chosen to do the detail analysis. It was found that the annual mea n horizontal gradients of pressure, temperature and wind speed are 0.0064hPa/km, 0.035℃/km and 1.1×10-4/s, respectively. In the case of a squall, the l ongitudinal horizontal gradients of pressure, temperature and wind speed are 1.2 hPa/km, 0.035℃/km and 5.3×10-3/s, respectively and the minus horizontal gradient of temperature and relative humidity maintained over 45 minutes until the squall reached. In the case of thunderstorm the horizontal gradient of each element is similar to the case of squall, but no minus horizontal gradient of relative humidity occurred. In the case of continuous heavy rain, the 0.15hPa/km pressure gradient and 0.5℃ /km temperature gradient and 90° wind direction difference were maintained over 10 hours. When a cold air arrived, the temperature and pressure gradient would reverse, but relative humidity gradient would keep invariable, and the gradients would last until the end of process.
3 Analysis on Characteristics of VWP Wind Product of Doppler Weather Radar Duri
ng Rainfall Process
2008, 34(10):20-26.
DOI: 10.7519/j.issn.1000-0526.2008.10.003
Abstract:
Based on the study of VWP product reliability and its capability representing at mospheric humidity, the characteristics of VWP product in spring large scale rai nfall process in Nanjing are statistically analyzed and studied in detail by usi ng Doppler weather radar data of Nanjing. The results show that VWP product pres ents respective characteristics at different stages of rainfall development (for mation, development and dissipation). The main points are as follows: ND area in VWP images presents a wedge shape and is decreasing quickly, which indicates th e appearance of rainfall within 2 hours; the existence of warm advection, shear layer and strong wind area are propitious to the continuance and reinforcement o f the precipitation; an abrupt reduceof the highest vane in the VWP production or the emergence of ND area in the mi ddle layer predicts that the rainfall will end soon.
Based on the study of VWP product reliability and its capability representing at mospheric humidity, the characteristics of VWP product in spring large scale rai nfall process in Nanjing are statistically analyzed and studied in detail by usi ng Doppler weather radar data of Nanjing. The results show that VWP product pres ents respective characteristics at different stages of rainfall development (for mation, development and dissipation). The main points are as follows: ND area in VWP images presents a wedge shape and is decreasing quickly, which indicates th e appearance of rainfall within 2 hours; the existence of warm advection, shear layer and strong wind area are propitious to the continuance and reinforcement o f the precipitation; an abrupt reduceof the highest vane in the VWP production or the emergence of ND area in the mi ddle layer predicts that the rainfall will end soon.
2008, 34(10):27-33.
DOI: 10.7519/j.issn.1000-0526.2008.10.004
Abstract:
There is a big discrepancy of typhoon Wipha (0713) tracks forecasts by various models. The forecasts say that the typhoon Wipha (0713) would turn nor thward in the sea of northern Taiwan Island towards bias N in the east of 120°E , but the actual path is in the west of 120°E after landing at the coast of Zhe jiang and Fujian provinces. To understand the reasons for this discrepancy, ever y kind of data is applied to study the possible causes. It shows that (1) the er rors in the numerical prediction product are the main reasons. (2) One ridgetw o troughs situation in the Eurasian 500 hPa height field, the westerly index evo lution from low to high and the subtropical high index periodical enhancement ar e disadvantageous to typhoon Wipha turning bias N in the sea northeast of Taiwan . (3) The terrain impact shoreleft changing and Harbor attraction,as well as dynamic field and thermal field distribution led typhoon Wipha to the west in the northeast sea of Taiwan.
There is a big discrepancy of typhoon Wipha (0713) tracks forecasts by various models. The forecasts say that the typhoon Wipha (0713) would turn nor thward in the sea of northern Taiwan Island towards bias N in the east of 120°E , but the actual path is in the west of 120°E after landing at the coast of Zhe jiang and Fujian provinces. To understand the reasons for this discrepancy, ever y kind of data is applied to study the possible causes. It shows that (1) the er rors in the numerical prediction product are the main reasons. (2) One ridgetw o troughs situation in the Eurasian 500 hPa height field, the westerly index evo lution from low to high and the subtropical high index periodical enhancement ar e disadvantageous to typhoon Wipha turning bias N in the sea northeast of Taiwan . (3) The terrain impact shoreleft changing and Harbor attraction,as well as dynamic field and thermal field distribution led typhoon Wipha to the west in the northeast sea of Taiwan.
2008, 34(10):34-39.
DOI: 10.7519/j.issn.1000-0526.2008.10.005
Abstract:
Based on the particle concentration, descending dust, satellite remote observati on，the aerosol extinction coefficient derived from Lidar observational data and physical quantity of sanddust weather process affecting Dalian, the character istic and dynamical mechanism of sanddusts invading Dalian were analyzed. The results show that the concentration of inhalational and total suspending particl es was increased remarkably and the descending dusts added in sanddusts. It transported at a level below 4 kilometers in Dalian, mostly located between 1 a nd 3 kilometers with the maximal aerosol extinction coefficient over 2.0km-1 . It exceeds 0.5km-1 near the ground and may be 1.3km-1 in the cas e of strong process. The precondition was that there were sanddust transportat ions of westwind or northwestwind jet streams, the glide streams in the rear of the front near Dalian contributed mainly to the rising of sanddusts concentration near the ground. The stronger the glide streams moved, the heavie r the pollution induced by sanddusts near the ground.
Based on the particle concentration, descending dust, satellite remote observati on，the aerosol extinction coefficient derived from Lidar observational data and physical quantity of sanddust weather process affecting Dalian, the character istic and dynamical mechanism of sanddusts invading Dalian were analyzed. The results show that the concentration of inhalational and total suspending particl es was increased remarkably and the descending dusts added in sanddusts. It transported at a level below 4 kilometers in Dalian, mostly located between 1 a nd 3 kilometers with the maximal aerosol extinction coefficient over 2.0km-1 . It exceeds 0.5km-1 near the ground and may be 1.3km-1 in the cas e of strong process. The precondition was that there were sanddust transportat ions of westwind or northwestwind jet streams, the glide streams in the rear of the front near Dalian contributed mainly to the rising of sanddusts concentration near the ground. The stronger the glide streams moved, the heavie r the pollution induced by sanddusts near the ground.
2008, 34(10):40-49.
DOI: 10.7519/j.issn.1000-0526.2008.10.006
Abstract:
By using hourly Tbb data, lightning data, rainfall observations from a utomatic weather stations, the mesoscale characteristic of a torrential rain in Sichuan and Chongqing during July 16-20, 2007 was analyzed in order to obtain va luable information on evaluating and predicting such case of torrential rain. Th e study shows that this case was a coupling result of two mesoscale systems whic h are Plateau Vortex and Southwestern Vortex. The strong and thick positive vort ex column and the accompanying updraft are the main factors, which cause the con vection bodiesgenerate and eliminate in turn and lead to torrential rain to occ ur repeatedly in the nearby area. Three mesoscale cloud systems (MCS) in the sou thwestern vortex initiate the heavy rain directly. In this case, generation and elimination of the MCS and the convective clouds in the western Tibetan plateau performed in a way of seesaw. The movement direction of lightning can represent the direction of movement in strong convection zone, which is also the direction of movement of heavy rainfall in the future. The emergence of lightning is befo re the precipitation, a sudden increase or decrease of lightning have a certain significance to the increase or decrease of precipitation in the future.
By using hourly Tbb data, lightning data, rainfall observations from a utomatic weather stations, the mesoscale characteristic of a torrential rain in Sichuan and Chongqing during July 16-20, 2007 was analyzed in order to obtain va luable information on evaluating and predicting such case of torrential rain. Th e study shows that this case was a coupling result of two mesoscale systems whic h are Plateau Vortex and Southwestern Vortex. The strong and thick positive vort ex column and the accompanying updraft are the main factors, which cause the con vection bodiesgenerate and eliminate in turn and lead to torrential rain to occ ur repeatedly in the nearby area. Three mesoscale cloud systems (MCS) in the sou thwestern vortex initiate the heavy rain directly. In this case, generation and elimination of the MCS and the convective clouds in the western Tibetan plateau performed in a way of seesaw. The movement direction of lightning can represent the direction of movement in strong convection zone, which is also the direction of movement of heavy rainfall in the future. The emergence of lightning is befo re the precipitation, a sudden increase or decrease of lightning have a certain significance to the increase or decrease of precipitation in the future.
2008, 34(10):50-59.
DOI: 10.7519/j.issn.1000-0526.2008.10.007
Abstract:
Radar echo feature of a heavy rainfall event is discussed on the basis of analyz ing NEXRAD products during the mesoscale-β heavy rainfall convective system e vent in June 18th, 2006 occurred in Yongding City. Conclusion is drawn as follow s: largescale circulation, ample water vapor and stronger ascending movement ar e advantageous weather background of severe rainfall. The results of show that severe rainfall is led by local convective echoes strengthening a nd integrating; lowermiddle layer cold advection triggers the strong convectio n. And convective cells show typical features of severe precipitation system. Co nverse wind region and good vertical movement strengthens the development of con vective cells. The server largerscale rainfall area moves along the same direc tion as echoes do, which cause socalled “train domino effect". Furthermore, s ystem moves slowly, which helps severe rainfall continue.
Radar echo feature of a heavy rainfall event is discussed on the basis of analyz ing NEXRAD products during the mesoscale-β heavy rainfall convective system e vent in June 18th, 2006 occurred in Yongding City. Conclusion is drawn as follow s: largescale circulation, ample water vapor and stronger ascending movement ar e advantageous weather background of severe rainfall. The results of show that severe rainfall is led by local convective echoes strengthening a nd integrating; lowermiddle layer cold advection triggers the strong convectio n. And convective cells show typical features of severe precipitation system. Co nverse wind region and good vertical movement strengthens the development of con vective cells. The server largerscale rainfall area moves along the same direc tion as echoes do, which cause socalled “train domino effect". Furthermore, s ystem moves slowly, which helps severe rainfall continue.
2008, 34(10):60-66.
DOI: 10.7519/j.issn.1000-0526.2008.10.008
Abstract:
From October 131, 2006, the research set 3 monitoring points respectively in 4 0meter, 120meter, 220meter platforms and monitored the air quality with PM2.5 concentration. Combined with PM10 concentration and visibility r ange, the temporal and spatial distribution of pollutants was analyzed. The result ind icated that PM2.5 concentration varies obviously at different vertical hei ghts. The overall trend of pollutant distribution at three levels was 120meter >40meter>220meter. The mixinglayer depth and atmospheric stability is the most important factors to influence PM2.5 concentration. PM2.5 conce ntration also varied in different time as follows: from 23:00 to 11:00, the conc entration in 120meter platform was significantly higher than other levels; fro m 11:00 to 18:00, due to the enhancement of atmospheric diffusion capacity, the pollutant concentration at three levels started to decline; from 18:00 to 23:00, the pollutant concentration at lower level showed higher value. Everyday the PM2.5 mass concentration varied in a certain regular way. PM2.5 concen trations peak usually was caused by weather condition and traffic exhauster. And it also indicated that in Tianjin city the overall varying trend of PM10 and PM2.5 concentration seems the same, there was a negative correlation b etween the visibility range and the level of fine particles pollution. The preci pitation process is the important mechanism of removing particle from atmosphere .
From October 131, 2006, the research set 3 monitoring points respectively in 4 0meter, 120meter, 220meter platforms and monitored the air quality with PM2.5 concentration. Combined with PM10 concentration and visibility r ange, the temporal and spatial distribution of pollutants was analyzed. The result ind icated that PM2.5 concentration varies obviously at different vertical hei ghts. The overall trend of pollutant distribution at three levels was 120meter >40meter>220meter. The mixinglayer depth and atmospheric stability is the most important factors to influence PM2.5 concentration. PM2.5 conce ntration also varied in different time as follows: from 23:00 to 11:00, the conc entration in 120meter platform was significantly higher than other levels; fro m 11:00 to 18:00, due to the enhancement of atmospheric diffusion capacity, the pollutant concentration at three levels started to decline; from 18:00 to 23:00, the pollutant concentration at lower level showed higher value. Everyday the PM2.5 mass concentration varied in a certain regular way. PM2.5 concen trations peak usually was caused by weather condition and traffic exhauster. And it also indicated that in Tianjin city the overall varying trend of PM10 and PM2.5 concentration seems the same, there was a negative correlation b etween the visibility range and the level of fine particles pollution. The preci pitation process is the important mechanism of removing particle from atmosphere .
2008, 34(10):67-73.
DOI: 10.7519/j.issn.1000-0526.2008.10.009
Abstract:
The basical genes about climatic regionalization were choosen by age average air temperature, precipitation, mean square error of each of 88 stations in Xinjian g in 1961—2005 ,and the fuzzy matrices were built by coefficient between every station. The climate style in the Northern Xinjiang.the Southern Xinjiang and Ti anshan Mountains were regionalized to the different clustering level, further mo re, dry and cold coteau, representative wind section were also regionalized. Reg ionalization result were anatomized well with weather character and geography si ght,and 3 regions and represent stations of Xinjiang climate operation were conf irmed by the regionalization result. The regionalization result were made of bas is for other professional regionalization.
The basical genes about climatic regionalization were choosen by age average air temperature, precipitation, mean square error of each of 88 stations in Xinjian g in 1961—2005 ,and the fuzzy matrices were built by coefficient between every station. The climate style in the Northern Xinjiang.the Southern Xinjiang and Ti anshan Mountains were regionalized to the different clustering level, further mo re, dry and cold coteau, representative wind section were also regionalized. Reg ionalization result were anatomized well with weather character and geography si ght,and 3 regions and represent stations of Xinjiang climate operation were conf irmed by the regionalization result. The regionalization result were made of bas is for other professional regionalization.
10 Verification on Typhoon Track Forecast by Operational
Typhoon Numerical Models of China in 2007
2008, 34(10):74-80.
DOI: 10.7519/j.issn.1000-0526.2008.10.010
Abstract:
Verification of typhoon track forecast in 2007 was conducted to understand the p erformance of five operational typhoon numerical models of China. The datasets i nclude the typhoon center location data officially issued by CMA and t he associated prediction of typhoon track provided by five typhoon operational f orecast centers of China. The evaluation includes distance error, skill score an d index of stability, etc. The result shows that: 1) the minimum (maximum) case- averaged 24h/48h distance error, the minimum(maximum) 24h/48h distance error for the best(worst) case prediction and 24h/48h model-averaged distance error are 1 22.8km/246.3km (180.7km/304.4km), 11.2km/10.1km (1429.7km/1003.7km) and 147km/2 67km, respectively. Pabuk (No. 0707 numbered by CMA) brought big difficulty to a majority of typhoon models; 2) the model-averaged skill score against the clima tic-persistent statistical track prediction approach of Shanghai Typhoon Institu te (STI) is 32%/43% for 24h/48h prediction; 3) stability indexes in terms of dis tance, direction of movement and availability are also presented to give an over all evaluation. Significant advantage of numerical model is identified against t he traditional statistical method in typhoon track prediction. However, it is al so recognized that most of the typhoon models witness deficiency in the case of landfall, particularly when typhoon making abrupt turning. This suggests that, i n addition to vortex initialization, more attention should be paid on improving the physics parameterization of boundary layer and land surface in typhoon numer ical model.
Verification of typhoon track forecast in 2007 was conducted to understand the p erformance of five operational typhoon numerical models of China. The datasets i nclude the typhoon center location data officially issued by CMA and t he associated prediction of typhoon track provided by five typhoon operational f orecast centers of China. The evaluation includes distance error, skill score an d index of stability, etc. The result shows that: 1) the minimum (maximum) case- averaged 24h/48h distance error, the minimum(maximum) 24h/48h distance error for the best(worst) case prediction and 24h/48h model-averaged distance error are 1 22.8km/246.3km (180.7km/304.4km), 11.2km/10.1km (1429.7km/1003.7km) and 147km/2 67km, respectively. Pabuk (No. 0707 numbered by CMA) brought big difficulty to a majority of typhoon models; 2) the model-averaged skill score against the clima tic-persistent statistical track prediction approach of Shanghai Typhoon Institu te (STI) is 32%/43% for 24h/48h prediction; 3) stability indexes in terms of dis tance, direction of movement and availability are also presented to give an over all evaluation. Significant advantage of numerical model is identified against t he traditional statistical method in typhoon track prediction. However, it is al so recognized that most of the typhoon models witness deficiency in the case of landfall, particularly when typhoon making abrupt turning. This suggests that, i n addition to vortex initialization, more attention should be paid on improving the physics parameterization of boundary layer and land surface in typhoon numer ical model.
2008, 34(10):81-89.
DOI: 10.7519/j.issn.1000-0526.2008.10.011
Abstract:
In order to improve the ability to use the products of GRAPES model, the 15 and 30km GRAPES model products in the whole summer of 2007 was verified. The results shows that the GRAPES models have good forecasting performance in aspect of pre dicting the position of precipitation, however, the two types of GRAPES models h ave the smaller precipitation intensity than the real observational precipitation at the Huaihe River Basin in the first ten days of the July. The position of average trough and ridge is consistent wi th that of the analytic data at 500hPa geo-potential height field. The forecast efficiency of 15km model is better than that of the 30km model for the height fi eld in Indian peninsula and western Pacific region. The position of north bounda ry of 5880 geo-potential meters is also close to the analysis field, but the wes tern ridge spot of subtropical high is eastward in comparison with the analysis field. The temperature transitions at 850hPa are all reflected by the two types of GRAPES models, and the temperature simulated by the 15km model is close to ob servations. Some errors of GRAPES models were found in predicting path and inten sity of typhoon SEPAT. The center of circulation is not evident before the SEPAT lands our main land and the wind speed is obviously small.
In order to improve the ability to use the products of GRAPES model, the 15 and 30km GRAPES model products in the whole summer of 2007 was verified. The results shows that the GRAPES models have good forecasting performance in aspect of pre dicting the position of precipitation, however, the two types of GRAPES models h ave the smaller precipitation intensity than the real observational precipitation at the Huaihe River Basin in the first ten days of the July. The position of average trough and ridge is consistent wi th that of the analytic data at 500hPa geo-potential height field. The forecast efficiency of 15km model is better than that of the 30km model for the height fi eld in Indian peninsula and western Pacific region. The position of north bounda ry of 5880 geo-potential meters is also close to the analysis field, but the wes tern ridge spot of subtropical high is eastward in comparison with the analysis field. The temperature transitions at 850hPa are all reflected by the two types of GRAPES models, and the temperature simulated by the 15km model is close to ob servations. Some errors of GRAPES models were found in predicting path and inten sity of typhoon SEPAT. The center of circulation is not evident before the SEPAT lands our main land and the wind speed is obviously small.
2008, 34(10):90-95.
DOI: 10.7519/j.issn.1000-0526.2008.10.012
Abstract:
Based on the data, collected in Haidian district in 2006, of the incid ence of preday’s infectious diarrhoea and the weather condition, a forecastin g model of infectious diarrhea medicalmeteorological grade and risk level evalu a tion model were set up by using multiple regression probability grade analysis. The Pearson correlation coefficient of the incidence and the atmospheric vapor p ressure was 0.8340. The proportion of variance contribution of vapor pressure wa s highest (70.5%). Mean wind speed and diurnal temperature had higher proportion of variance contribution than other factors. If the difference between the fore casted grade and actual grade is no more than 1, the forecasted grade of the inf ectious diarrhoea disease medicalmeteorological grade forecast models would be defined as proper grade. The mean ratio of proper forecasted grade forecast mod els was 98.5%, and the exact proper rate (for 6 time periods) was 62.9～66.4％. It is concluded that the forecasting model of infectious diarrhoea disease medic almeteorological grade forecast and the risk level evaluation model could well forecast the incident of infectious disease during Bingjing Olympic Games, and be helpful for the Center of Disease Prevention and Control (CDC) to provide pu blic health services for citizens according to the outcomes of the models.
Based on the data, collected in Haidian district in 2006, of the incid ence of preday’s infectious diarrhoea and the weather condition, a forecastin g model of infectious diarrhea medicalmeteorological grade and risk level evalu a tion model were set up by using multiple regression probability grade analysis. The Pearson correlation coefficient of the incidence and the atmospheric vapor p ressure was 0.8340. The proportion of variance contribution of vapor pressure wa s highest (70.5%). Mean wind speed and diurnal temperature had higher proportion of variance contribution than other factors. If the difference between the fore casted grade and actual grade is no more than 1, the forecasted grade of the inf ectious diarrhoea disease medicalmeteorological grade forecast models would be defined as proper grade. The mean ratio of proper forecasted grade forecast mod els was 98.5%, and the exact proper rate (for 6 time periods) was 62.9～66.4％. It is concluded that the forecasting model of infectious diarrhoea disease medic almeteorological grade forecast and the risk level evaluation model could well forecast the incident of infectious disease during Bingjing Olympic Games, and be helpful for the Center of Disease Prevention and Control (CDC) to provide pu blic health services for citizens according to the outcomes of the models.
2008, 34(10):96-101.
DOI: 10.7519/j.issn.1000-0526.2008.10.013
Abstract:
As a part of Energy Management System(EMS), daily load forecasting is very important for safety and economy operation of the power system. For the sak e of studying meteorological factors on the impact of load more comprehensively , the meteorological load is deduced from the load of guilin power network accor ding to daily data from 2005 to 2006. The correlations between meteorological lo ad and meteorological factors show that the relations between load and meteorolo gical factors can be obtained more exactly through the meteorological load, whic h can provide important reference for the work of load forecasting of administra tion of power supply. Finally, a method based on similar days is adoped for the forecasting of meteorological load and integrated electric load and the actual e xample shows that the results are satisfactory for the daily load forecasting.
As a part of Energy Management System(EMS), daily load forecasting is very important for safety and economy operation of the power system. For the sak e of studying meteorological factors on the impact of load more comprehensively , the meteorological load is deduced from the load of guilin power network accor ding to daily data from 2005 to 2006. The correlations between meteorological lo ad and meteorological factors show that the relations between load and meteorolo gical factors can be obtained more exactly through the meteorological load, whic h can provide important reference for the work of load forecasting of administra tion of power supply. Finally, a method based on similar days is adoped for the forecasting of meteorological load and integrated electric load and the actual e xample shows that the results are satisfactory for the daily load forecasting.
2008, 34(10):102-107.
DOI: 10.7519/j.issn.1000-0526.2008.10.014
Abstract:
At present, national prediction system for dekad and monthly extreme h igh temperature has not been undertaken. Here, a national forecast system for ex treme high temperature was developed. It is a powerful platform that regularly i ssued three kinds of predicting products at website with three methods of dynami cal monthly forecast model, statistical downscaling and physical analogue using percentile values at 90%, 95% and 99% as relative thresholds and 35℃or 38℃ as absolute thresholds. The products consist of probability prediction, the numb er of day exceeding 35℃ or 38℃ involving 7 periods: 1-10 day, 11-20 d ay, 21-30 day, 1-30 day, 6-35 day and 31-40 day. The spatial distribution of correlatio n coefficient between hindcast and observation shows that high value areas are d ifferent among these methods. So it is hard to say which method is better than o thers. Thus three predicted results should be considered as well as distribution of correlation coefficient before final extreme high temperature prediction. Th e predictions by these methods for July, 2007 were generally close to the observ ation. But the result by statistical downscaling method is better, and that by D ERF is worse relatively.
At present, national prediction system for dekad and monthly extreme h igh temperature has not been undertaken. Here, a national forecast system for ex treme high temperature was developed. It is a powerful platform that regularly i ssued three kinds of predicting products at website with three methods of dynami cal monthly forecast model, statistical downscaling and physical analogue using percentile values at 90%, 95% and 99% as relative thresholds and 35℃or 38℃ as absolute thresholds. The products consist of probability prediction, the numb er of day exceeding 35℃ or 38℃ involving 7 periods: 1-10 day, 11-20 d ay, 21-30 day, 1-30 day, 6-35 day and 31-40 day. The spatial distribution of correlatio n coefficient between hindcast and observation shows that high value areas are d ifferent among these methods. So it is hard to say which method is better than o thers. Thus three predicted results should be considered as well as distribution of correlation coefficient before final extreme high temperature prediction. Th e predictions by these methods for July, 2007 were generally close to the observ ation. But the result by statistical downscaling method is better, and that by D ERF is worse relatively.
2008, 34(10):108-114.
DOI: 10.7519/j.issn.1000-0526.2008.10.015
Abstract:
According to the 30a climatic data about 95 stations of Hunan Province from 1971 to 2000, and the data hour by hour about part of observation stations in Hunan from 2003 to 2004, this paper analyses Dongting Lake’s effect on temperature to surrounding areas and the whole province, the results show that: the yearly mea n temperature in the eastern part of the lake region shows a warm tongue. Dongti ng Lake changes the usually distribution trend of Hunan province that the temper ature in the south is higher than in the north, so that the monthly mean temperature in Hunan also shows distributions of East-West and transition. The lake district is the low-value areas of highest temperature, and the high-valu e of minimum temperature, daily range of temperature is lower. Compared to the s ame latitude and longitude regions of the province, and latitude of Hunan, the m onthly mean daily range of temperature in the lake district is lower, particular ly in the summer half year, in July it appears in the anti-phase, the temperatur e curve is more stable, and the daily maximum temperature appears 2 hours later, in the same weather conditions, the temperature amplitude of variation is alway s a little smaller, but under different weather conditions, the difference of th e daily maximum temperature and the difference of the daily minimum temperature are largest in sunny days, smaller in cloudy days and smallest in rain days.
According to the 30a climatic data about 95 stations of Hunan Province from 1971 to 2000, and the data hour by hour about part of observation stations in Hunan from 2003 to 2004, this paper analyses Dongting Lake’s effect on temperature to surrounding areas and the whole province, the results show that: the yearly mea n temperature in the eastern part of the lake region shows a warm tongue. Dongti ng Lake changes the usually distribution trend of Hunan province that the temper ature in the south is higher than in the north, so that the monthly mean temperature in Hunan also shows distributions of East-West and transition. The lake district is the low-value areas of highest temperature, and the high-valu e of minimum temperature, daily range of temperature is lower. Compared to the s ame latitude and longitude regions of the province, and latitude of Hunan, the m onthly mean daily range of temperature in the lake district is lower, particular ly in the summer half year, in July it appears in the anti-phase, the temperatur e curve is more stable, and the daily maximum temperature appears 2 hours later, in the same weather conditions, the temperature amplitude of variation is alway s a little smaller, but under different weather conditions, the difference of th e daily maximum temperature and the difference of the daily minimum temperature are largest in sunny days, smaller in cloudy days and smallest in rain days.
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ISSN:1000-0526 CN:11-2282/P