用VB和Fortran语言混合编程开发气象软件          下载免费PDF全文

杜文娟  李建东 《气象与环境科学》2007,30(4):88-90

阐述了利用VB和Fortran语言混合编程开发气象预报系统的两种方法,一种是利用VB的shell函数调用可执行文件法,另一种是利用VB调用Fortran生成的动态链接库法,并具体介绍了如何通过DLL实现VB 6.0和Fortran的接口,最终实现VB的可视化界面与Fortran强大数值计算能力相结合的新思路.  相似文献   

《气象与环境科学》2007年总目次          下载免费PDF全文

杜文娟  李建东 《气象与环境科学》2007,30(4):95-96

阐述了利用VB和Fortran语言混合编程开发气象预报系统的两种方法,一种是利用VB的shell函数调用可执行文件法,另一种是利用VB调用Fortran生成的动态链接库法,并具体介绍了如何通过DLL实现VB 6.0和Fortran的接口,最终实现VB的可视化界面与Fortran强大数值计算能力相结合的新思路.  相似文献   

Analysis of the spectral response of flourishing-withering vegetation changes based on ground spectral measurements     

Guli Japper  Chen Xi  Zhao Jin  Ma ZhongGuo  Chang Cun  Zhang XueRen 《中国科学D辑(英文版)》2007,50(1):86-96

A structural mode was used to characterize vegetation composition at the plant leaf level and a flourishing-withering ratio was developed. The spectral responses of vegetation with different flourishing-withering ratios were analyzed, the change rates of the chlorophyll and moisture content indices of vegetation with different flourishing-withering ratios were compared, and correlations between the chlorophyll and moisture content indices were analyzed. The results reveal that leaves with an intermediate flourishing-withering ratio can increase the absorption signatures of vegetation and that band ranges of 570–700 nm and 1300–1540 nm can play a role in indicating changes in the flourishing-withering ratios of vegetation; NPQI, NPCI, R₆₉₅/R₄₂₀, R₆₉₅/R₇₆₀, R₇₅₀/R₇₀₀, the peak-value area of red selvedge, the red selvedge amplitude, the ratio between the red selvedge amplitude and the minimum amplitude, and the NDVI of vegetation change regularly with the change in flourishing-withering ratios, and these nine vegetation indices are highly related to the chlorophyll content. Vegetation indexes of NDWI and PRI are very sensitive to the flourishing-withering change in vegetation and are closely related to the moisture content, and the correlation coefficient is higher than 0.9. The derivative of the spectra is more effective in describing changes in the structural mode of vegetation with different flourishing-withering ratios, especially at band ranges of 552–628 nm and 630–686 nm, and it is more sensitive to the mixed flourishing-withering ratios of leaves rather than to the vegetation indices. The red selvedge position in the spectrum is highly related to the chlorophyll content and is not sensitive to changes in the structural mode of mixed flourishing-withering leaves. The red selvedge parameters are sensitive to changes in the flourishing-withering ratio at the peak-value area of the red selvedge amplitude and the ratio between the red selvedge amplitude and the minimum amplitude. The effect of a sand background on the spectrum of withering leaves is higher than that of flourishing leaves; the effect of a sand background increases with increasing proportions of withering leaves, the superposition effect of the sand background on mixed flourishing-withering leaves is about 7% at visible light bands of 400–700 nm and 1300–1540 nm, and is over 10% at the near infrared band range of 700–1300 nm.  相似文献   

气象温湿度因子与蚕病发生的初步探索     

焦金儿  吴雄伟  常素萍  刘强军  杜建华 《山西气象》2007,(1):9-11

蚕病是蚕农在养蚕过程中最顾忌的,2005年着重对养蚕过程中蚕病发生与温度、湿度问题进行定点对比试验。分析了温湿度与蚕病发生直接和间接的关系,提出了相应的生产调节措施。  相似文献   

大到暴雪天气模型及数值产品释用预报方法   总被引：3，自引：1，他引：3  

常军  李祯  布亚林  李素萍  刘莎 《气象与环境科学》2007,30(3):54-56

用欧洲数值预报产品格点资料,对1986年11月-2002年3月河南省出现的87个大到暴雪个例进行对比分析,将大到暴雪划分为3个类型,即高原低槽型、阻高-横槽型和L型,对每个型进行合成平均,建立了大到暴雪的天气学概念模型.为提高样本中大到暴雪的概率,先将样本进行消空处理,然后选取物理意义清晰、天气学意义明确的预报因子,分别建立了全省分片大到暴雪1-7 d预报方法,在业务试应用中取得了较好的预报效果.  相似文献   

河南夏季高温气候特征及500 hPa环流型   总被引：4，自引：1，他引：4       下载免费PDF全文

常军  李素萍  余卫东  孔剑君 《气象科技》2007,35(6):776-780

对河南省40个代表站1961～2005年45年夏季大于等于35℃高温日数进行经验正交函数(EOF)展开分析。方差累积贡献率和空间分布特征显示,前3个典型场基本能反映河南夏季高温日数分布的主要特征,前3个模态的累积方差贡献率达85%,据此得出河南夏季大于等于35℃高温日数的时空分布类型:全省一致型、西北—东南差异型和西南—东北差异型。第1模态对应的时间系数序列的变化幅度最大,第2模态对应的时间系数序列的变化幅度比前一个时间序列要小,第1模态的时间系数演变显示,河南夏季高温日数平均呈减少的趋势,且存在2～4年、8～14年的周期变化,目前河南夏季高温日数正处于偏多的时段。应用逐日20:00500hPa ECMWF北半球格点资料,对1991～2005年15年河南典型的大面积持续高温下的环流形势进行普查、分类,分别求各种类型下的环流平均场,从而得到河南省高温的两种环流型,即贝加尔湖高压型和副热带高压型。  相似文献   

Tectonic evolution of Korean Peninsula and adjacent crustal fragments in Asia: Introduction     

Chang Whan Oh  K. Sajeev  Sung Won Kim  M. Santosh 《Gondwana Research》2006,9(1-2):19

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Reservoir operation using grey fuzzy stochastic dynamic programming     

Fi‐John Chang  Shyh‐Chi Hui  Yen‐Chang Chen 《水文研究》2002,16(12):2395-2408

This paper presents an optimal regulation programme, grey fuzzy stochastic dynamic programming (GFSDP), for reservoir operation. It is composed of a grey system, fuzzy theory and dynamic programming. The grey system represents data by covering the whole range without loss of generality, and the fuzzy arithmetic takes charge of the rules of reservoir operation. The GFSDP deals with the multipurpose decision‐making problem by fuzzy optimization theorem. The practicability and effectiveness of the proposed approach is tested on the operation of the Shiman reservoir in Taiwan. The current M5 operating rule curves of this reservoir also are evaluated. The simulation results demonstrate that this new approach, in comparison with the M5 rule curves, has superior performance with regard to the total water deficit and number of monthly deficits. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

The mean oceanic residence time     

Chen-Ping Chang  Lian-Sen Liu  Chen-Tung Chen 《Marine Chemistry》1982,11(3):293-295

In this note the significance of heat of hydration and electronegativity in the study of oceanic residence times of elements is discussed.  相似文献   

VLF input impedance of a loop antenna embedded in the magnetosphere     

T.N.C. Wang  C.D. Chang 《Planetary and Space Science》1973,21(10):1810-1815

An analysis is made to calculate input impedance of a loop antenna for radiation of the VLF whistler mode in the magnetosphere. The magnetosphere is assumed to be represented by a cold, uniform and collisionless magnetoplasma medium. Assuming a uniform current distribution of a circular loop, oriented at an arbitrary angle with respect to the Earth's magnetic field line, several closed-form expressions for the loop impedance have been derived. It is found that the loop input reactance is in substantial agreement with the self-inductance of a loop in free space and that the radiation resistance for a small loop can be as large as ～10 ² Ω. It is also found that a second order quasi-static theory is quite valid for determining the input impedance for small loops radiating VLF whistlers in the magnetosphere.  相似文献