在特殊疫情背景下《城市地理资讯学》MOOC课程教学实施效果分析     

廖萱  陈家朗  郭彦彤  甘振扬  黄文声 《测绘地理信息》2021,46(2):123-126

在新冠肺炎疫情期间,线上教学大规模开展,相关线上教学问题逐渐成为研究热点。传统的测绘地理类课程的教学方式主要是上课时以老师传授知识为主,课后以学生完成作业为辅的方式进行。但是,这种教学方式比较单一,并且在科学化考核和促进学生学习主动性等方面存在诸多问题。然而,线上网络课程是通过互联网以电子设备为教学平台,具有不受教学时空限制、教学方法灵活多样和丰富学生的学习方式等优点。因此,对《城市地理资讯学》MOOC(massive online open courses)课程实施效果进行分析,为其他测绘地理类网络课程设计提供优化思路,同时为无法进行面授教学的特殊时期提供一种有效的教学方案。  相似文献   

AN OPERATIONAL STATISTICAL SCHEME FOR TROPICAL CYCLONE INDUCED RAINFALL FORECAST     

李晴岚  兰红平  陈仲良  曹春燕  李程  王兴宝 《热带气象学报(英文版)》2015,21(2):101-110

A non-parametric method is used in this study to analyze and predict short-term rainfall due to tropical cyclones(TCs) in a coastal meteorological station. All 427 TCs during 1953-2011 which made landfall along the Southeast China coast with a distance less than 700 km to a certain meteorological station- Shenzhen are analyzed and grouped according to their landfalling direction, distance and intensity. The corresponding daily rainfall records at Shenzhen Meteorological Station(SMS) during TCs landfalling period(a couple of days before and after TC landfall) are collected. The maximum daily rainfall(R-24) and maximum 3-day accumulative rainfall(R-72) records at SMS for each TC category are analyzed by a non-parametric statistical method, percentile estimation. The results are plotted by statistical boxplots, expressing in probability of precipitation. The performance of the statistical boxplots is evaluated to forecast the short-term rainfall at SMS during the TC seasons in 2012 and 2013. Results show that the boxplot scheme can be used as a valuable reference to predict the short-term rainfall at SMS due to TCs landfalling along the Southeast China coast.  相似文献   

综合治理太湖污染的一种方法：为环境目的而挖泥     

陈荷生  范成新 《湖泊科学》1998,10(S1):117-122

The eutrophication of Lake Taihu is becoming more serious day by day and more urgent to be comprehensively harnessed. The lake sludge is considered as a important polluting factor. To control the internal pollution source of Lake Taihu and restore its water ecological environment, this paper put forward an idea of the dredging for environmental purposes. It was on the basis of the research on the sludge storage and physical/chemical characteristics. The technical keys are sludge-dredging depth, time, method and sludge treatment. The requirements and scheme for the environmental dredging work in Lake Taihu were also analyzed in detail.  相似文献   

在EBEX-2000实验资料中湍流谱和局地各向同性特征   总被引：10，自引：4，他引：6  

刘树华  李洁  刘和平  梁福明  王建华  Johnny C.L.CHAN  Andrew Y.S.CHENG  胡非  刘辉志 《大气科学》2005,29(2):213-224

采用2000年8月在美国加州棉花地两个高度上应用超声三分量仪、快速响应050206 温度和湿度仪进行的EBEX-2000 (International Energy Balance Experiment,2000,EBEX-2000)风速三分量、温度和湿度湍流实验观测数据,计算分析了湍流速度、温度和湿度谱在不同稳定度下的特征.对湍流的局地各向同性进行了讨论并与Kansas和长白山原始森林湍流实验得到的结果进行了比较,得到了一些湍流特征量在不同下垫面情况下的一些有意义的特征.  相似文献   

The 30–60-day oscillation in the East Asian summer monsoon and its time-dependent association with the ENSO     

By KYUNG-SOOK YUN  BAOHUA REN  KYUNG-JA HA  JOHNNY C. L. CHAN  JONG-GHAP JHUN 《地球，A辑:动力气象学与海洋学》2009,61(5):565-578

Based on 30–60-day oscillation in the East Asian summer monsoon (EASM), the relationship between its northward propagation and ENSO (El Niño and Southern Oscillation) was investigated. To explicitly describe the 30–60-day monsoonal evolution, an empirical orthogonal function (EOF) analysis was carried out on the temporal-latitude section of the longitudinal average for 115°E–120°E. The principal 30–60-day EASM mode captures a northward propagation of well-organized intraseasonal oscillation (NISO). Using the associated time series of the first mode, we found a significant lagged correlation between interannual variability of the NISO and ENSO. Its lagged correlations with NINO indices have a quasi-biennial (QB) characteristic through the preceding summer and the concurrent summer. Their relationship was found by the regression analysis relating the low-level circulation to the ocean temperature. The western North Pacific anticyclone and the anticyclone-induced easterly vertical wind shear anomalies induce the dynamical linkage between the NISO and QB-type ENSO. It is shown that the NISO is more closely tied with QB-type ENSO in its phase than in its amplitude, and may be connected to the anomalous easterly wind and the eastward evolution of an oceanic Kelvin wave, which is associated with abrupt ENSO transition. The predictability on ENSO and NISO is examined through the canonical correlation analysis.  相似文献   

Effects of the Indo-China Peninsula Heat Fluxes on the 1998 South China Sea Summer Monsoon          下载免费PDF全文

SHI Xueli  Johnny C. L. CHAN  K. C. CHOW  DING Yihui 《Acta Meteorologica Sinica》2005,19(4):457-468

1. IntroductionBecause the South China Sea (SCS) is one of theregions where the Asian summer monsoon onset oc-curs earliest, the SCS summer monsoon (SCSSM) hasalways been a research focus, especially in recent yearswith the implementation of the SCS Monsoon Exper-iment (SCSMEX) (e.g., Tao and Chen, 1987; Changand Chen, 1995; Lau et al., 2000; Ding and Li, 1999;Ding and Liu, 2001; Li and Wu, 2000; Xie et al., 1998;Zhang et al., 2004). Climatologically, the SCSSM on-set is a rem…  相似文献   

Impacts of Urbanization on the Precipitation Characteristics in Guangdong Province,China     

Meng YAN  Johnny C. L. CHAN  Kun ZHAO 《大气科学进展》2020,37(7):696-706

With the development of urbanization, whether precipitation characteristics in Guangdong Province, China, from 1981 to 2015 have changed are investigated using rain gauge data from 76 stations. These characteristics include annual precipitation, rainfall frequency, intense rainfall(defined as hourly precipitation ≥ 20 mm), light precipitation(defined as hourly precipitation ≤ 2.5 mm), and extreme rainfall(defined as hourly rainfall exceeding the 99.9 th percentile of the hourly rainfall distribution). During these 35 years, the annual precipitation shows an increasing trend in the urban areas.While rainfall frequency and light precipitation have a decreasing trend, intense rainfall frequency shows an increasing trend. The heavy and extreme rainfall frequency both exhibit an increasing trend in the Pearl River Delta region, where urbanization is the most significant. These trends in both the warm seasons(May-October) and during the pre-flood season(April-June) appear to be more significant. On the contrary, the annual precipitation amount in rural areas has a decreasing trend. Although the heavy and extreme precipitation also show an increasing trend, it is not as strong and significant as that in the urban areas. During periods in which a tropical cyclone makes landfall along the South China Coast, the rainfall in urban areas has been consistently more than that in surrounding areas. The precipitation in the urban areas and to their west is higher after 1995, when the urbanization accelerated. These results suggest that urbanization has a significant impact on the precipitation characteristics of Guangdong Province.  相似文献   

ANALYSIS OF LEAST SQUARES SMOOTHING OPERATORS IN THE FREQUENCY DOMAIN*     

S. H. CHAN  L. S. LEONG 《Geophysical Prospecting》1972,20(4):892-900

The process of data smoothing by least squares operators with real and symmetric coefficients is shown to be equivalent to linear digital filtering. Study of the frequency response functions of the least squares operators shows that these operators are essentially low-pass filters. The frequency response functions are characterized by the presence of a main lobe centered about the zero frequency together with a number of minor lobes of smaller amplitudes at higher frequencies. The predominant band of frequencies which is passed by a least squares operator occurs within the main lobe of the frequency response function. The filtering characteristics of a least squares operator are dependent on the degree of the polynomial and the number of data points. Generally speaking, the higher the degree of the polynomial the broader the pass band of the filter will be. But the effect of the number of data points on the pass band is exactly opposite. Several figures showing the plots of the half-power frequency, the quarter-power frequency, and the half-width of the main lobe for a large number of least squares operators with different combinations of the degree of the polynomial and the number of data points are presented in this paper. These figures will be helpful to those people who wish to make a selection of least squares operators suitable for their purposes.  相似文献   

两种微藻凝集素对几种不同类型细胞的凝集作用   总被引：1，自引：0，他引：1       下载免费PDF全文

郑??怡  陈晓清  林雄平 《海洋科学》2008,32(6):30-34

经离子交换和分子筛层析从紫球藻（Porphyridium cruentum）和海水小球藻（Chlorella sp．）中分离纯化得到2种凝集素，研究它们对几种不同类型细胞即动物和人血红细胞、海洋和淡水微藻、细菌和真菌的凝集活性。研究结果表明，2种微藻凝集素对它们当中一些类型的细胞或种类具有不同程度的凝集活性，其中对水生聚胞藻（Synechocystis aquetilis）的凝集活性最强，最低质量浓度只需0．0313g／L。  相似文献   

Ground–Space–Sky Observing System Experiment during Tropical Cyclone Mulan in August 2022     

Pak-wai CHAN  Wei HAN  Betty MAK  Xiaohao QIN  Yongzhu LIU  Ruoying YIN  Jincheng WANG 《大气科学进展》2023,40(2):194-200

Forecasting tropical cyclone track and intensity is a great challenge for the meteorological community, and safeguarding the life and property of people living near the coast is an important issue. One major reason for challenging forecasts is the lack of observations over the vast oceans. During tropical cyclone Mulan between 8 and 10 August 2022over the northern part of the South China Sea, the meteorological authority and research institutes of Chinese mainland collaborated with the meteorolo...  相似文献