Current Issue
- On the Research Progress of the Subtropical EastAsian Monsoon and Related Problem
- 2008 Vol. 27 (增刊): 1-7.
- Abstract ( ) PDF (804KB) ( )
- The subtropical East Asian summer monsoon, as a part of the East Asian monsoon system, influences the weather and climate as well as associated extreme meteorological events over eastern China. The context reviews the its definition, the feature (onset, moving, north boundary and rain season), the effect of Tibetan Plateau on it and its research progress for the recent 30 years, and then discusses the closely related problem of regional climate, climate varibility and change.
- Review for Climate Change of Meiyu over theYangtze-Huaihe Basins
- 2008 Vol. 27 (增刊): 8-15.
- Abstract ( ) PDF (1659KB) ( )
- Chinese meteorologists havebegun to research Meiyu over China since 1930s. With the advent of long series of historical Meiyu data, long\|term change (especially interdecadal change) of Meiyu is investigated by many scholars. Under climate change of Meiyu over China, analysis of period, features of long\|term change for characteristic variables of Meiyu, nonhomogeneous features for change of Meiyu, and influencingfactors of Meiyu′s climate change are reviewed and summarized. And untypicalcharacteristics for climate change of Meiyu are further analyzed. Questions deserving further discussion are finally put forward in this paper.
- The Application Progress of Scenario in Climate Change Research
- 2008 Vol. 27 (增刊): 16-21.
- Abstract ( ) PDF (944KB) ( )
- Scenarioanalysesare considered to be a better way to linkclimatechange and impact research in recent years. This papersummarizes the scenarioapplication progressin climate change researchfrom itsdefinition,classificationand so on. IPCC released emission scenarios over the years had been reviewed and new IPCC scenarioshad been introduced in this paper which be help for future climate change research.
- An Application of Regional Climate Model(RegCM_NCC)in Operation over the Eastern China(II): 10\|Year Summertime Hindcasts
- 2008 Vol. 27 (增刊): 32-41.
- Abstract ( ) PDF (9434KB) ( )
- 10\|year(1998\_2007) hindcasting experiments over the East China are presented by using the regional climate model (RegCM\|NCC) that is nested with T63 global atmosphere\|ocean coupled modelof National Climate Center/AMS. The results demonstrate that RegCM\|NCC can roughly reproduce the averaged summertime surface temperature and total precipitation over the East China, and its performance is better than thoseof T63 global model of National Climate Center in spite of that over the south of East China remains to be improved. Also the model can give rather real the surface temperaturedeparture and precipitation over the East China in some years of 1998\_2007. Based on the sensitive experiments, the Ps skill scores of the model can be improved, to some extent, through reducing the model integration step, enlarging its horizontal resolution and its domain covering the Tibetan Plateau. As far as the summertimeintegrationis concerned, The earlier initial time (February 1) in comparisonto March 1 and April 1, seems to be suitable the most for the East China.
- The Application of Reginal Clime Model (RegCM_NCC)in Operational Forcast(Ⅲ): 10\|Year Hindcast Experiments of Spring and Autumn
- 2008 Vol. 27 (增刊): 42-51.
- Abstract ( ) PDF (11258KB) ( )
- 10\|year hindcast experiments (1998-2007) of the surface air temperature and precipitation of sping and autumn over the Eastern China are performedby using regional climate model (RegCM_NCC) that is nested in a global atmosphere\|ocean coupled model, and the results of the hindcast experiments are analyzed by using Psskill and the simplifiedPs. The results indicate that the model has some capabilities in predicting the air temperature and precipitation of sping and autumn, especiallythe scores of the autumn higher than that of the spring; and the hindcasts of temperature better than that of precipitation. The hindcast scores of RegCM_NCCare higher than those of the National Climate Center T63 global model in spring and autumn. Three group experiments are designed to select the sutiable parameters of the model for operation over the eastern China. The results show that the hindcasts with lagger domain are better than those with smaller domain; smaller integration stephas higher score; the initial integration from Januarary 1 has the highest scores for spring hindcast; and the integration from July are best for autumn.
- An EOF Iteration Downscale Modeling Scheme and Its Applicationto East China Meiyu Season Precipitation Prediction
- 2008 Vol. 27 (增刊): 52-63.
- Abstract ( ) PDF (11947KB) ( )
- A traditional EOF method was engaged to establish the monthly rainfall statistical downscaling models for the East China Meiyu season (from June to July) by taking the 200 hPa and 500 hPa heights derived from China National Climate Center T63 global model as model climate predictors, and taking the precipitationanomaly percentage at 916 observation stations of China as predictands, in which, cross\|validation method was used to determine the reasonable truncated explainingvariance of EOF iteration. In order to improve the drownscaling skill, a resolution to expand small sample which is a difficulty common in statistical downscale modeling, was then put forward, was then put forward. Such efforts directly resulted in the exciting predictions during Meiyu season from 2007 to 2008. Finally, the performance of the model was assessed and further its confidence intervalof average skill scores was estimated by means of Bootstrap method.
- A Predicting Method on the Low\|Frequency Synoptic Weather Map
- 2008 Vol. 27 (增刊): 64-68.
- Abstract ( ) PDF (3273KB) ( )
- A new forecasting method, low\|frequency weather map (LFSC), is introduced in this paper. By using LFSC, the active characteristicsof the low\|frequency cyclones and anticyclones are analyzed and based on its active characteristics forecast the precipitationprocesses. The forecast results are good in Shanghai region from July to September 2008 and its forecasting period of validity is about 20~40 days. The LFSC method can be apply to precipitation process in medium\|range and long\|range forecasts.
- An Autoregressive Statistical Model for Extended\|Range Prediction
- 2008 Vol. 27 (增刊): 69-75.
- Abstract ( ) PDF (4404KB) ( )
- Using the Jones′autoregressive statistical model and 700 hPa wind of NCEP/NCAR reanalysis data in 1998\_2007, and considering the characteristicof the regional climate, the summer forecast model for the extended\|rang (10~30 days) are constructed for operation from May to October, in which firstly the main components of the wind fields are chosen by means of Empirical Orthogonal Function analysis (EOF), then the lastest five pentad main components (PCs) are utilized to predict the coming five pentad PCs and finally the corresponding wind fields are derived from combination of the PCs forecast models use. The results indicate that the forecast skill scores for the low\|frequencyzonal winds seem to be larger, implying the coming the third to fifth pentad predictions thus given along mid\| and lower\|reaches of the YangtzeRiver.
- Climate Change of Meiyu in Shanghai in Past a Century
- 2008 Vol. 27 (增刊): 76-83.
- Abstract ( ) PDF (3023KB) ( )
- The climatic change characteristics of Meiyu in Shanghai in past a century are examined in this paper using Meiyu data from 1875 to 2006. The basic climatic features of Meiyu in Shanghai are basically in accordance with those in the mid\| and lower\|reaches of Yangtze River. The onset time or ending time for ShanghaiMeiyu (SM) shows significant postponing trend over the past a century and more. And 1940s is a distinct turning decade for them. After then, the probability of late onset of SM increases; the probability of abnormally late (early) outset of SM increases (decreases). Furthermore, the probabilitiesfor abnormally large rainfall amount or rainfall strength e of SM are also greater after 1940s; abnormally long (short) duration time of SM tends to increases (decreases). The variation trend is not clear for the duration time and rainfall amount over the whole years discussed although they have a slight increase after 1940s compared with those before 1940s. The significant period length for the onset time, duration time and rainfall strength of SM are around 22, 4.2 and 3.3 years, respectively while its rainfall amount and ending time exhibit no obviousperiod within the years investigated. In addition, the climatically statistics of SM are in common with regional meiyu over the mid\| and lower\|reaches of Yangtze River to much extent. But the period characteristics and climate change of SM differ much with regional Meiyu.
- Features of Low Frequency Oscillation for Moisture Transportduring Typical Drought/Flood Year over Yangtze\|Huaihe Basins
- 2008 Vol. 27 (增刊): 84-91.
- Abstract ( ) PDF (14467KB) ( )
- Using the daily NCEP/NCAR reanalysis dataset and the observation rainfall data of China in1971\_2000,the characteristics of low\|frequency oscillation (LFO) for moisture transport and its relation with rainfall during drought/flood year in the mid\|and lower\|reaches of Yangtze River are analyzed. Results show that obvious LFOexists in meridional moisture transport in the mid\|and lower\|reaches of Yangtze River during flood year while that during drought year is unnoticeable. The anti\|cyclonic low\|frequency moisture transport circulation over the west Pacific triggeredby the northward propagation of cyclonic low\|frequency circulation from the tropics interacts with the moisture transport from the north of Yangtze\|Huaihe basins, which is corresponding to more rainfall during Meiyu period. On the contrary, in active low\|frequency perturbation without northward propagation and the anti\|cyclonic low\|frequency moisture transport circulation over the west Pacific westward propagation may attribute to the less rainfall during Meiyu period.
- Analysis on Relationship between Meiyu Rainfall in Shanghaiand Temperature Ascent from Winter (JF) to Spring
- 2008 Vol. 27 (增刊): 92-97.
- Abstract ( ) PDF (4167KB) ( )
- Using the monthly temperature and precipitation data of 160 observation stations in China, Meiyu rainfall data in Shanghai as well as 700 hPa winds of NCEP/NCAR reanalysis data during 1951\_2006, the relation between the Meiyu rainfall in Shanghai and the temperature ascent from winter (JF) to spring over the eastern China are analyzed. The results reveal that the Meiyu rainfall amount in Shanghai has a closely negativerelation with the temperature ascent from winter (JF) tospring. Furthermore, the value of the temperature ascent corresponding to abnormal Meiyu is seemly associated with 700 hPa meridional\|wind over the mid\|latitude area (20°~30°N, 100°~120°E) during the same period. Namely, the abnormal increase of Meiyu rainfall amount tends to occur when the earlier difference of the meridional\|wind gets larger, consequently, the difference of rainfall between spring and preceding\|winter thus rise and the value of the temperature ascent declines, and vice versa.
- Quasi-Biweekly Oscillation of the Subtropical Summer MonsoonRainfall over East China and Its Possible Maintaining Mechanism
- 2008 Vol. 27 (增刊): 98-108.
- Abstract ( ) PDF (10888KB) ( )
- This study begins with the definition of the subtropical summer monsoon rainfall (SMR) region over East China by using the daily precipitation data at 740 stations of China during 1958\_2007. Based on this definition, the quasi\|biweekly oscillation(QBWO) of the SMR is investigated. The results show that a 10~20 d period is obvious and important in the intraseasonal cycle of SMR. Its propagation has characteristics of local oscillation. The related analysis shows that the total SMR has close relationship with its QBWO intensity in interannual time scale. Further, the possible maintaining mechanism of QBWO in the SMR is discussed by using daily NCEP I reanalysis data during 1958\_2007. It is found that the QBWO in the SMR is closely related to the convective disturbance over the West Pacific ocean and the low\|frequency circulation in the low level triggered by the above convection. The latter moves northwestwards under the unified effect of Rossby wave and the environmental flow, which might be the main reason maintaining the QBWO in the SMR.
- The Relationship bewteen Meiyu and the Intensityof East Asian Summer Monsoon
- 2008 Vol. 27 (增刊): 109-117.
- Abstract ( ) PDF (5915KB) ( )
- An investigation is performed to probe the relationship between Meiyu and the intensity of East Asian summer monsoon based on Meiyu rainfall and Monsoon indices series for 1951\_2001. Some clear facts are revealed:There are 9 matching patterns between South China Sea summer monsoonand Subtropical summer monsoon, which can be classified as 3 categories by Meiyu rainfall anomaly: Rainy\|prone, rainless\|prone, and uncertainty. Composited analyses of rainy areas and geopotential height for each pattern reach some results which is significant for the recognization and long\|term forecast of Meiyu.
- Interannual Variability of Spring Persistent Rainover Southeastern China and Its Effect Factor
- 2008 Vol. 27 (增刊): 118-123.
- Abstract ( ) PDF (4538KB) ( )
- The Spring Persistent Rains (SPR) over southeastern China (SEC) is rainy season of spring and just before the onset of the South China Sea monsoon.It is a unique synoptic and climatic phenomenon in East Asia and is the result of the mechanical and thermal forcing of the Tibet Plateau (TP). The daily rainfall data at 730 stations of China in 50 years and NCEP/NCAR monthly data are employed to make the correlations and composited analysis in order to clarify the factors affecting interannual SPR rain. The results show that SPR has obvious interannual variability. In El Nioyears, equatorialmiddle\|east Pacific SST rises, the West Pacific Warm Pool (WPWP) SST drops, the West Pacific Sub\|High strengthens, and its abnormal anti\|cyclone circulation dominates over the South China Sea (SCS). The temperature rises and the southwesterly strengthens at lower troposphereover SCS. As a result, SPR rain significantly increases. And vice versa, in La Niayears, SPR rain remarkably decrease. In addition, time\|lag correlation analysis shows that the tropical Pacific multivariateENSO index (MEI) significantlycorrelates with SPR rainfall leading 6 months. In conclusion, ENSO, the largest and the strongest global climate abnormity event, also has profound effects on the circulation and rainfall of the transferringSPR over southeastern China.
- Characteristics of Maximum and Minimum TemperatureVariations and Their Differences between Urban andSuburban Areas in Shanghai from 1960 to 2006
- 2008 Vol. 27 (增刊): 124-130.
- Abstract ( ) PDF (2262KB) ( )
- Based on the temperature data at 10 meteorological stations in Shanghai, the temporal and spatial variation characteristics and the difference of maximum and minimum temperatures between urban and suburban areas in Shanghai during 1960\_2006 were studied. The results indicated that in the past 47 years, the mean annual maximum and minimum temperatures are 20.1℃ and 12.5℃, respectively, increased with a tendency ratio of 0.29℃/10a and 0.39℃/10a in turn. The maximum temperature increase the highest during spring and the minimum temperature increase the highest during winter. Both the maximum and the minimum temperatures raised an abrupt change in the middle and end of 1980s, with the abrupt timing of 1988 and 1989, respectively. Both the maximum and the minimum temperatures were negative departure before 1990s, and then had been turned to be positive one since 1990s . The difference of maximum and the minimum temperatures between urban and suburban areas has been significant since 1987. The maximum temperature in urban areas was higher than those both in suburban areas, and also the maximum temperature in inland higher than that along river and coastal regions. The difference of maximum temperature between urban and suburban areas in recent 20 years was 0.4℃ higher than that of during 1960\_1980, and the difference of maximum temperature between urban and exurban areas was 0.6℃ higher than that of during 1960\_1980. The spatial pattern and variation trend of minimum temperature were roughly the same as the maximum temperature. In recent 20 years, the difference of minimum temperature between urban and suburban areas was 0.5℃ higher than that of during 1960\_1980, and the difference of minimum temperature between urban and exurban areas was 0.8℃ higher than that of during 1960\_1980. The mean daily range of air temperature was 7.5℃ Shanghai, being decreased significantly in the past 47 years. The decrease of daily range of air temperature was probably to associate with the asymmetrical variation of the maximum and minimum temperatures; moreover, and it significantly it associate with the sunshine duration and cloud cover too.
- Characteristics of Local Air Temperature VariationInfluenced by Shanghai\|Urbanization
- 2008 Vol. 27 (增刊): 131-137.
- Abstract ( ) PDF (5256KB) ( )
- The influenceof urbanizationon the surface air temperature, and the interdecadal variabilityof the heat\|island and the related extreme events in Shanghai are analyzed by means of the daily data such as the average, the maximum and minimum surface air temperatures, water vapor, pressure and relative humidity at eleven observation stations from 1875 to 2006. The results show that the areas impacted by Shanghai urban heat\|island tends to enlarge, the centre of annual mean heat\|island is to shift to thesouth in the recent years. Influencing by urbanization, the heat\|wave events over the down\|town occur more and more frequency, and the content of water vapor is getting smaller, especially in the suburb areas where has been less impacted by heat\|island. The dew\|point has been significantly decreasedand the local climate tends to be \!drying and warming\"although the mean air temperaturehas been changed little depending on the analysis of multi\|year heat\|wave events.
- Climatic Characteristics and Change Laws of Fogand Haze Days in Shanghai
- 2008 Vol. 27 (增刊): 138-143.
- Abstract ( ) PDF (5173KB) ( )
- Based on the fog and haze data from 11 meteorological stations in Shanghai, the temporal and spatial climatic characteristics and change laws of fog and haze days in recent 50 years were analyzed. The results indicate that from 1951 to 2007, the fog days in urban area of Shanghai was significantly decreased. Fog days in exurban area of Shanghai were the most in 1970s and 1980s, the least in the first 7 years of the 21st centuries. Haze days in urban and exurban areas of Shanghai were increased from 1954 to 2007 as a whole, and such increase was mainly occurred after 1980. During the period of 2001 to 2003, haze days were the most in Shanghai. In winter, Shanghai has the most fog and haze days, and in summer, it has the least fog and haze days. From 1960 to 2007, fog days were decreased in most regions of Shanghai, but haze days were increased in all regions of Shanghai, especially the haze days increased rapidly in urban.
- Effect of Urban Heat Island on Heat Waves in Summer of Shanghai
- 2008 Vol. 27 (增刊): 144-149.
- Abstract ( ) PDF (2144KB) ( )
- Using the data of daily maximumtemperature at 11 stations in summer half\|year (from June to October) in 1955\_2004 and hourly mean temperature derived from 6 AWS urban, suburban and rural sites in Shanghai, the effect of increased urban heat island magnitude onheat waves in summer has been analyzed. It has been found that the mean maximum temperature, extreme temperature and hot days in summer measured at the urban and sub\|urban sites all appeared increasing trends, with the largest value at urban site, larger one at suburban sites and the smallest oneat the rural sites. Urban heat island induced temperature increase excesses the regional warming which lead to the more hot days, higher extreme temperature and longer duration, but the wide covered high temperature did not increase so much.
- Statistical Analysis of Atmospheric Precipitable Water VapourObserved by GPS in Yangtze River Delta Region
- 2008 Vol. 27 (增刊): 150-157.
- Abstract ( ) PDF (5526KB) ( )
- The climate features of atmospheric water vapor in Yangtze River Delta region are analyzed by use of 7 years′ Precipitable Water Vapor(PWV) data observed by GPS observational Network, and the relations between climate characteristics of Atmospheric Precipitable Water vapor and heavy rain in Meiyu season are also studied. The results show that: PWV distribution in the Yangtze River Delta region are the higher the north and higher the west, the average PWV during summer months are higher than that of the winter months about 20mm, and the PWV gradient from south to north is clearly higher than that from west to east, which shows that moisture transportedto Yangtze River Delta region by northern flow is important. PWV in Yangtze River Delta region has a significant seasonal change, the maximum PWV are found in August in summer, and the minimum PWV occurred in January in winter, and the PWV changes in spring and autumn are strong than that in summer and winter; while the PWV in Yangtze River Delta region has no significant cyclical changes in year and in day. In addition, there is obvious correlation between PWV and severeprecipitation duringMeiyu Period, when the PWV value quickly increase from the low-value to more than 60 mm, or PWV values remained at high values after severeprecipitation, severeprecipitation often occurs, which maybe provides a new signal for us to forecasts heavy rain in the Yangtze River Delta.
- A PV Inversion Analysis of Strong Cyclone over the Yangtzeand Huaihe River Valleys during the Meiyu Period of Summer
- 2008 Vol. 27 (增刊): 158-169.
- Abstract ( ) PDF (15829KB) ( )
- In the potential vorticity (PV) framework, the process of a strong cyclongenesis is analyzed and researched in detail during Meiyu periodin 2003 based on piecewise Ertel PV inversion techniques. Results show that the forcing effect at upper\|level exerts important impacton the development of low\|level cyclonic circulation, which mainly enhanced north wind on the upstream and south wind on the downstream of low\|level cyclone and consequently brought aboutdevelopment of high pressure ridgeson the upstream anddownstream of the cyclone. Theyprovide favorable background for enhancement of the cyclone as well asfurther strengthenthe cyclonic vorticity in the mature process of cyclone. At the same time, the low\| and mid\|level perturbationsalso play important role in the development of low\|level cyclonic circulationfrom beginning to end. It can strengthen the south wind on the downstream of low\|level cyclone center and further enhance the cyclonic circulation, which also does important contribution to the formation of upper\|level cyclone. On the other hand, the heatinganomalyat bottom exerts adverse effects on development of low\|level cyclonic circulation by decreasing the cyclonic vorticity. In addition, the analysis about effects of dry or moistair suggest that saturation moist air plays a significant role on decrease of geopential height on the center of low\|level cyclone and surfacepressurebesides strengthening of low\|level cyclonic circulation.
- Temporal and Spatial Variations of NDVI and Its Responseto East Asian Summer Monsoon in East China
- 2008 Vol. 27 (增刊): 170-174.
- Abstract ( ) PDF (9534KB) ( )
- Temporal and spatial variationsof NDVI and its response to East Asian summer monsoonin East China was analyzed based on the SPOT-VGT NDVI, NCEP/NCAR reanalysis monthly average data of meridional windat 700 hPa and East Asian summer monsoonindex from April 1998to March 2008. The results indicate that NDVI in East China significantly increased with a linear trend of 0.07 per 10 year from 1999 to 2007, the most the increasein spring and summer is, and the least the increasein winter is. NDVI increased more in northernJiangsu and Anhui, and eastern Henan, but decreased more in the Yangtze River Delta, and some regions of Pearl River Delta. In the regions to the Norther areas of 30°N in East China NDVI varied more in winter, spring, summer and autumn, but in regions to the souther areas of 30°N in east China NDVI varied more only in winter and autumn. The response of NDVI to East Asian summer monsoonis obvious. In summer, with higher latitudeof the meridional south windat 700 hPa level, and with stronger East Asian summer monsoon, the NDVI in East China is higher.
- Study on Characteristic of Rainfall Infiltration in TypicalFarmland Soil in the Lower Reach of Yangtze River
- 2008 Vol. 27 (增刊): 175-182.
- Abstract ( ) PDF (4144KB) ( )
- The rainfall infiltration were simulated based on the principle of water balance introduced Smith′s infiltration model, by experimented data of artificial rainfallin typical farmland inYangtzeriver Delta region, to find the rule of soil rainfall infiltration. The results indicated the rainfall infiltration intensity by Smith′s model calculated was consistent with the experimental results, the correlation determination coefficient(R2) was >0.81, the standard error(SE)was ≤0.08 mm·min-1. The infiltration intensity in high flow period in farmland increases with rainfall intensity, with the decreases of the soil moisture, with the decrement of soil texture. The coefficientof rainfall infiltration was middle loam >heavy loam, lower soil moisture>higher soil moisture, less rainfall intensity>bigger rainfall intensity.
- Preliminary Study on the Biology and Ecology Characteristicof Direct Sowing Rice Optimal Seeding Stages
- 2008 Vol. 27 (增刊): 183-189.
- Abstract ( ) PDF (3033KB) ( )
- Using the method of correlation analysis to analyze different seeding data of direct sowing rice, the results showed thatthe relation between rice yield and seeding date in Shanghai area is the parabola type, and optimal seeding time of direct sowing rice in Shanghai region is on 13 June. The best effective panicle numberunder the best seeding date is 360×104 hm-2, with 105 grains on per panicle, 11%~12% of unfilled\|grains rate, 25 g of 1000\|grain weight, 43%~44% of economic coefficient, and 150 days during the whole growing season. The correlation coefficientbetween yield and the leaf area index of the peak period of tiller, dry matter weight of leaf are -0.8957( P<0.05) and -0.9928 (P<0.01), respectively. The correlation coefficient that yield and leaf area index, dry matter weight duringheading to maturityare 0.8505 (P<0.1) and 0.8130 (P<0.1), respectively. During the tiller period and higher tiller period, sunshine durationare higher than 70 h,the effective panicle number obviouslyincreases.When sunshine durationbetween initial panicle formation tocell divisionislower than 160 h, total grains obviously decreases. When the minimum air temperature while blooming is lower than 18℃, the rate of unfilled grain reaches above 18%. Average minimum air temperature before and after headingis lower than 23℃ or sunshine durationis lower than 200 h, 1000\|grain weight is lower than 23 g.
- Characteristics of Temporal Variability of Soil Moisture in Shanghai
- 2008 Vol. 27 (增刊): 190-195.
- Abstract ( ) PDF (3619KB) ( )
- Based on continuously soil volumetric water content datum of 3 observationstationsin Shanghai from 1 July 2007 to 30 June 2008 with a time resolution every 30 min and daily precipitation, the characteristics of temporal variability of soil moisture and precipitation in Shanghai and its relationship were analyzed using trend analysis method. The results indicated that there were mostly unimodaldistributions of daily variability of relative moisture of soil in all seasons of 10~30 cm in Shanghai, except for unimodaldistributions of relative moisture of soil in 40 cm and 50 cm in winter, distributions of which in other seasons were not obviously. There werefour distribution types of daily variability of relative moisture of soil infive depthsin sunny, overcast, cloudy and rainyday,and the time appearing of wave crest and wave troughin 10~30 cmpassedbackward with the increasingof soil depth. Distribution of 10 day relative moisture of soil in shallow soil wasmore identical with which of 10 day precipitation than deeper layer, and thefluctuate intensityof 10 day relative moisture of soil of deeper layer wasslightly less than the shallow layer of soil.
- An Application of Numerical Modeling to ShanghaiOffshore Wind Energy Resource Assessment
- 2008 Vol. 27 (增刊): 196-202.
- Abstract ( ) PDF (4623KB) ( )
- On account of the difficultiesin the process of offshore wind energy assessment due to lack of observation data along the coastal areas, the numericalmodelingwas applied towind energy resource assessment. Firstly, the 1\|year integration of the TAPM model has been conducted, and its preliminary output results have been checked with wind tower observation data, then the systematical errors of the model have beencorrected according to the temporal distribution of the errors, and finally the annual average wind energy resource with the horizontal resolution of 1 km×1 km at the lower model levels were obtained by combining the above\|corrected simulation results with historical wind observation data of weather station.
- An Application of Microscale Meteorological Modelto Environment Impact Assessment
- 2008 Vol. 27 (增刊): 203-209.
- Abstract ( ) PDF (3708KB) ( )
- Using the microscalemeteorological model(Envi\|met) and gaspollutiondispersion model, and taking the Ruijin No2 road businessbuilding project in Shanghai as an example, the influence of the traffic waste gas on the buildings is simulated. Based on the parameters such as the distribution characteristics of buildings and underlying surface, and verified wind direction, wind speed, the intensity and heightof pollutant, the finized spatial distributionof gas pollutant densityover related area is obtained with the Envi\|met model, andfurthermore, the simulations by Envi\|met model are compared with that by regulatory atmospheric dispersion model. Theresults indicate that simulations from two models are relatively similar with each other, and because of covering the rather real distribution characteristics of buildings and wind fields around them, Envi\|met model presents the more reasonable and detaildistribution of gas pollutant. The applications of microscalemeteorological models to environmentimpact assessment can be used to supplement the regulatory atmospheric dispersion modeland seemly will have good prospectsin application.
- Evaluation on Effects of Meteorological Conditions on ElectricalComsumption in Megathermal Days of Shanghai
- 2008 Vol. 27 (增刊): 210-217.
- Abstract ( ) PDF (1744KB) ( )
- The impact of meteorological condition on the electric consumption in shanghai was appraised using the data such as the daily electrical consumption, maximum electricity load and meteorological elements from June to September of 2003\_2006 and 121 megathermal days of 2003\_2006. The results showed that the risk of the high\|increasing of daily electricity consumption and maximum electricity load in megathermal days were higher than that from June to September. The fore\|and post\|evaluation model of the meteorological variation of the daily electricity consumption and maximum electricity load were constructed, and the fitting errors of the model were analyzed from June to September and in megathermal days, the regression of the model were significant statistically, the fitting results of the model in megathermal days were better than those from June to September. The evaluation model made the satisfied performance from June to September and the megathermal days of 2007, the performable results of the model in megathermal days were better than those from June to September, but the fore\|evaluation errors tended to increase when the sudden fall\|down of temperature occured during persistent high temperature days, similarly, the post\|evaluation error of the model tended to increase on rainy day during the high temperature days.
- Research on Meteorological Condition InfluencingBlue Algae Bloom in Tailake
- 2008 Vol. 27 (增刊): 218-223.
- Abstract ( ) PDF (1071KB) ( )
- Meteorological condition influencingblue algae bloomin Tailakeare investigated by use of concentrationdata of TN, TP, SD in Tailake during 1992\_2006, blue algae bloom date and the corresponding meteorologicaldata (ex. temperature, sunshine, rainfall, relative humidity, wind speed) from Dongshanweather station. Results from statistical analysis show that accumulated active temperatureand sunshine duration exert important influences on blue algae bloom. When water qualityis satisfied with eutrophication, blue algaeis ready to bloom with accumulated active temperature(≥18℃) above 370℃·d forthree ten\|day and sunshine durationmore than 208 hours. On the contrary, bloom ofblue algaeis in unconspicuousassociation withrelative humidity, rainfall and wind speed.
- Preparatory Research on Automatic Cloud Type ClassificationTechnique Based on MODIS Data
- 2008 Vol. 27 (增刊): 224-229.
- Abstract ( ) PDF (4083KB) ( )
- It is the basic work to discriminatethe cloud types by use of remote sensing data in the several meteorological research fields. In this paper, the classification test betweencloud and backgroundas well as different cloud types was finished after the essentialpre\|processingand data analysis work were performed, at the same time the operational potentialof this method was discussed. The results show that the better classification effect can be got by use of traditional classificationmethod with texture features based on the gray co\|occurrencematrix theory, based on the statisticalanalysis the study show that the entropy feature among eight common used texturescan better describe the difference betweensea, land and differentcloud types especially for the snow which is frequently confusedwith the cloud type in the visible spectrum, at the same time, the research show that the entropy value show the very similar statisticcharacteristics in band1 and band4, so only one band betweenwhich can be selected in order to improve the processing speed.
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