区域土地利用变化及驱动力研究--以南宁市为例     

熊华  梁艳  邓鹏  梁强 《测绘信息与工程》2006,31(3):50-51

分析了南宁市1996~2003年的用地结构变化,通过对土地利用及其影响因子的相互作用关系和时空分布规律的定量分析,研究了土地利用变化的驱动力因素,并对耕地利用变化的驱动力因子进行了定量分析。  相似文献   

Q矢量和湿Q矢量在暴雨诊断中的应用比较   总被引：6，自引：1，他引：6  

赵桂香  程麟生  李新生 《气象》2006,32(6):25-30

利用常规探空和地面实测资料，以发生在2001年7月26—27日山西省晋中市的一次区域性暴雨为例，对准地转Q矢量和非地转湿Q矢量在暴雨诊断中的应用进行了定量对比分析，结果表明：（1）Q矢量对暴雨的预报有一定的指示作用，降水前期700hPa诊断效果最好，但在暴雨的强度和落区上存在明显偏差。而湿Q矢量在各层对暴雨均表现出良好的诊断特性，其散度辐合区与暴雨区有较好的对应关系，其强锋生出现6小时后开始产生强降水，且暴雨区与强锋生中心基本吻合，700hPa表现尤为突出。（2）Q矢量锋生函数分布表现出典型的准地转特征，而湿Q矢量锋生函数分布则具有明显的中尺度特征，因此，Q矢量适宜于研究与天气尺度系统相关的大气运动，而湿Q矢量更适宜于研究天气尺度系统激发的次级环流。湿Q矢量较准地转Q矢量更能反映出暴雨的落区和暴雨的中尺度特性，在反映暴雨的强度上也更具优越性。  相似文献   

A Short-Range Quantitative Precipitation Forecast Algorithm Using Back-Propagation Neural Network Approach   总被引：5，自引：0，他引：5  

冯业荣 《大气科学进展》2006,23(3):405-414

A back-propagation neural network （BPNN） was used to establish relationships between the shortrange （0-3-h） rainfall and the predictors ranging from extrapolative forecasts of radar reflectivity, satelliteestimated cloud-top temperature, lightning strike rates, and Nested Grid Model （NGM） outputs. Quan- titative precipitation forecasts （QPF） and the probabilities of categorical precipitation were obtained. Results of the BPNN algorithm were compared to the results obtained from the multiple linear regression algorithm for an independent dataset from the 1999 warm season over the continental United States. A sample forecast was made over the southeastern United States. Results showed that the BPNN categorical rainfall forecasts agreed well with Stage Ⅲ observations in terms of the size and shape of the area of rainfall. The BPNN tended to over-forecast the spatial extent of heavier rainfall amounts, but the positioning of the areas with rainfall ≥25.4 mm was still generally accurate. It appeared that the BPNN and linear regression approaches produce forecasts of very similar quality, although in some respects BPNN slightly outperformed the regression.  相似文献   

山旺中新世植被演替及古气候定量研究   总被引：10，自引：1，他引：9  

梁明媚  王宇飞  李承森 《古地理学报》2001,3(3):11-20

本文详细研究了山旺中新世22.95 m厚的硅藻土沉积层位上,以10-30 cm为间距所采集的130块孢粉样品,鉴定出111个孢粉类型;古植被演替的研究结果表明由老至新经历的5个阶段：“湿润环境下的混交中生林”,“干旱环境下的混交中生林”,“湿润湖岸环境下的混交中生林”,“山地、湿润及碱性等环境下的混交中生林”,和“碱性环境下的混交中生林”; 同时,首次成功地运用共存分析法定量地恢复了山旺中新世气候,得出古气候参数定量值如下：年平均温度15.6-17.2℃, 最热月平均温度24.7-27.8℃, 最冷月平均温度 5.0-6.6℃, 温度年较差20.5-25℃, 平均相对湿度72-75%, 年平均降雨量1162-1308 mm, 最湿月份平均降雨量148-180 mm, 最干月份平均降雨量16-59 mm, 最干及最湿月份降雨量的差值81-153 mm, 最热月份的平均降雨量108-111 mm。山旺中新世时期的气候波动范围为：年平均温度波动约3℃左右,最冷月份平均温度波动约4℃左右,最热月份平均温度波动约1℃左右,年平均降雨量波动约100 mm左右。总体反映山旺中新世气候温暖潮湿,冬季凉爽,夏季炎热。  相似文献   

REVIEWS OF GEOGRAPHIC SOFTWARE     

《The Professional geographer》1987,39(2):229-237

CHAOS CLlM 3.77 LP88 and TPR088 MAPEDIT PRODESIGN II RANDMAP SPATIAL AUTOCORRELATION SIMULATION GAME . Daniel A. Griffith STATA THINKTANK NOTEBOOK II  相似文献   

微型计算机在地理学的应用和限制     

叶嘉安 《地理学报》1988,(1)

本文讨论微机在地理学上的应用,介绍可以从英美市场获得的地理软件,并检讨微机在英美地理教学和研究上的一些限制,以促进其在国内地理学上的应用。现存的软件和硬件基本上可以满足地理教学和研究上的大部分需要。随着微机价格的降低,体积的缩小,计算速度、内外存储器容量以及可携带性的增加,其实际应用将会更广。微机已逐渐成为地理教学和研究中不可缺少的工具。  相似文献   

Quantitative climate reconstruction from pollen data in the Grand Duchy of Luxembourg since 15 000 yr BP     

J. Guiot  M. Couteaux 《第四纪科学杂志》1992,7(4):303-309

Monthly temperature and precipitation estimates for the period 15000–2000 yr BP are statistically derived from pollen analytical data obtained from a site near Echternach, Luxembourg. A continuous warming trend of over 10°C is recorded for the period 10500—8000 yr BP, along with a rise in precipitation of 500 mm. A fairly constant temperature characterised the period between 8000 and 2000 yr BP, though an episode of slight temperature decrease (-2°C) occurred at about 4500 yr BP. The most humid intervals seem to have been at around 9000–7000 and 5000–3000 yr BP (principally during the warm season: more continental influence). In contrast with results obtained from more southerly sites, the ‘Older Dryas’ climatic reversal is clearly recorded at Echternach slightly before 12000 yr BP. It is marked by a cooling in July temperature of about 4°C and a decrease in monthly precipitation of about 30 mm (40%).  相似文献   

NUMERICAL STUDY OF THE INFLUENCE OF WAVES AND TIDE-SURGE INTERACTION ON TIDE-SURGES IN THE BOHAI SEA     

尹宝树侯一筠  程明华苏京志林明祥  李明悝M.I.El-Sabh 《中国海洋湖沼学报》2001,19(2):97-102

Abstract The author‘s combined numerical model consisting of a third generation shallow water wave model and a 3-D tide-surge model with wave-dependent surface wind stress were used to study the influence of waves on fide-surge motion. For the typical weather case, in this study, the magnitude and mechanism of the influence of waves on tide-surges in the Bohai Sea were revealed for the first time. The results showed that although consideration of the wave-dependent surface wind stresses raise slightly the traditional surface wind stress, due to the accumulated effects, the computed results are improved on the whole. Storm level maximum modulation can reach 0.4 m. The results computed by the combined model agreed well with the measured data.  相似文献   

RURAL-URBAN LABORERS''MOBILITY AND URBANIZATION IN CHINA   总被引：1，自引：0，他引：1  

Xiaochen Meng 《中国地理科学(英文版)》1994,4(4):333-344

（孟晓晨）ＲＵＲＡＬ－ＵＲＢＡＮＬＡＢＯＲＥＲＳ＇ＭＯＢＩＬＩＴＹＡＮＤＵＲＢＡＮＩＺＡＴＩＯＮＩＮＣＨＩＮＡ￥ＭｅｎｇＸｉａｏｃｈｅｎ（ＰｅｋｉｎｇＵｎｉｖｅｒｓｉｔｙ，Ｂｅｉｊｉｎｇ１００８７１，ＰＲＣ）Ａｂｓｔｒａｃｔ：Ｕｒｂａｎｉｚａｔｋｉｎ...  相似文献   

高光谱技术在汝箕沟煤田烧变岩和Fe~(3+)丰度信息提取中的方法研究     

万余庆  闫永忠 《国土资源遥感》2003,(2)

介绍了宁夏汝箕沟煤田煤系地层和烧变岩的反射光谱特征。通过采样分析烧变岩的铁含量,借助多元回归分析,确定了烧变岩中Fe3+含量与某些波段反射率的定量关系,提出了利用高光谱遥感图像提取Fe3+的方法。文中以汝箕沟煤田大岭湾火区、阴坡火区为试点,证明了该方法是有效的。该成果再次证明了高光谱遥感技术在矿产资源调查和定量分析中的有效性。  相似文献