Enhancing the Simplified Surface Energy Balance (SSEB) approach for estimating landscape ET: Validation with the METRIC model

Evapotranspiration (ET) can be derived from satellite data using surface energy balance principles. METRIC (Mapping EvapoTranspiration at high Resolution with Internalized Calibration) is one of the most widely used models available in the literature to estimate ET from satellite imagery. The Simplified Surface Energy Balance (SSEB) model is much easier and less expensive to implement. The main purpose of this research was to present an enhanced version of the Simplified Surface Energy Balance (SSEB) model and to evaluate its performance using the established METRIC model. In this study, SSEB and METRIC ET fractions were compared using 7 Landsat images acquired for south central Idaho during the 2003 growing season. The enhanced SSEB model compared well with the METRIC model output exhibiting an r² improvement from 0.83 to 0.90 in less complex topography (elevation less than 2000 m) and with an improvement of r² from 0.27 to 0.38 in more complex (mountain) areas with elevation greater than 2000 m. Independent evaluation showed that both models exhibited higher variation in complex topographic regions, although more with SSEB than with METRIC. The higher ET fraction variation in the complex mountainous regions highlighted the difficulty of capturing the radiation and heat transfer physics on steep slopes having variable aspect with the simple index model, and the need to conduct more research. However, the temporal consistency of the results suggests that the SSEB model can be used on a wide range of elevation (more successfully up 2000 m) to detect anomalies in space and time for water resources management and monitoring such as for drought early warning systems in data scarce regions. SSEB has a potential for operational agro-hydrologic applications to estimate ET with inputs of surface temperature, NDVI, DEM and reference ET.     

北京春季沙尘天气特征和预报

根据北京地区资料分析了沙尘的年代变化、月变化,春季是沙尘天气的高发期并以浮尘和扬沙为主。造成沙尘天气的冷空气主要有三条路径,它与蒙古气旋、冷锋、高空急流等大尺度天气系统紧密相连。     

秦皇岛市沿海海洋渔业灾害性天气研究

本研究在渤海海区及秦皇岛海区灾情调查基础上,结合海上灾害性天气的数据,参考有关技术文献,对发生在秦皇岛岸区及近海海域的大风、大雾以及雷暴天气进行统计和成因分析,初步得出3种灾害性天气的基本特征,为气象部门对沿海区域的准确预报和渔民的安全出行提供了重要依据。     

陆地棉棉叶蝉数量气象预报模型研究

为了有效地防治棉叶蝉,促进华南棉花发展,研究了10个陆地棉品种田间棉叶蝉数与温度、降水的关系,建立了11个陆地棉棉叶蝉数量气象条件预报模型,其中3个分别可以较准确地预报抗虫棉95-1、石家庄428 2个品种和10品种平均单株棉叶蝉数。品种间棉叶蝉发生轻重对温度、降水的反应不同,为了提高预报精确度,每个品种应各建立一个棉叶蝉预报模型。     

Survey of cereal diseases and petts in the Netherlands. 5. Occurrence of Septoria spp. in winter wheat

Data of the annual surveys of circa 100 commerical winter wheat fields were compiled to describe epidemics ofSeptoria spp. in the Netherlands during 1974–1986. In May, during the first node stage,S. tritici was dominant whileS. nodorum was virtually absent. In July, during ripening,S. tritici on average dominated overS. nodorum, though in the most continental districts of the countryS. nodorum predominated.In May between 1974 and 1984, on average 56% of the fields showed leaf infections bySeptoria spp., while in July between 1975 and 1986, on average 83% of the fields showed leaf infections. Prevalence ofSeptoria spp. has increased during the surveys. Annual intensity ofSeptoria spp. in winter wheat crops was positively correlated with precipitation and negatively with average monthly sunshine duration during the harvest-month August of the previous growing season. The correlation with sunshine during August could indicate that ascospores play a major role in subsequent epidemics; but whether it is a causal relation remains to be answered.Present address: Center for Agrobiological Research (CABO-DLO), PO Box 14, 6700 AA Wageningen, the Netherlands     

气象数值预报模式WRF自动化业务构建系统的搭建试验

利用Shell、Fortran、Grads等高级语言构架并实现了WRF并行计算的自动化业务系统,该系统能够定时下载数据、定时运行,自动绘制数值预报产品,极大地提高了工作效率。     

气象,桑叶含氟量相关系统中的数学模式

利用 198 3年～ 1999年氟含量监测数据和气象资料 ,经多重相关分析 ,得出了平均温度、降雨量对桑叶含氟量的组合效应为最佳 ,复相关系数 Ry.1 2 为 0 .6 84 ( F=6 .514 >F0 .0 5 ,n=17)。建立了日平均温度、降雨量、桑叶含氟量相关系统的数学模式为 :Y=- 2 4 .0 6 4+ 3.56 5x1 - 0 .0 6 46 5x2 ± 15     

论帽儿山地区物侯季节的划分和农(林)时预测

本文分析了各种划分季节方法的利弊。肯定了以物候资料划分季节的优点;并以帽儿山地区多年的物候资料划分了季节。并编制了帽儿山地区的物候历。总结出了利用物候历预测农(林)时的经验公式 X=A_t+(B-C) X——某种农(林)时的预测日期 A_t——早于指示植物先开花的植物当年的开花始期 B——物候指示植物开花始期的多年平均日期 C——早于指示植物先开花的植物开花始期的多年平均日期。     

人体舒适度指数预报体系研究

本文利用河西走廊东部武威市 1 971 - 2 0 0 0年气象资料 ,统计分析各气象要素的变化规律 ,并探讨其对人体舒适度的影响 ,在国内外有关研究基础上 ,结合本区域特殊的气候状况 ,建立了人体舒适度指数的计算方法和相应的预报等级 ,并进行了效果检验和参数订正 ,可以满足气候相似地区城市环境气象预报业务的需要。     

Meteorological automated weather station data application for plant water requirements estimation

In order to adequately control water requirements for plants, it is necessary to perform continuous standardized meteorological conditions measurements from the largest possible number of points. This is possible by automated measurements which lead to an increase in the number of records and their immediate accessibility. Automatic stations provide a large amount of data; however, in comparison to standard stations, they do not obey the existing standard procedures. This particularly applies to the comparability of instruments and, to some extent, the time of measurements. Similarly, other differences include data processing procedures; hence a risk of results others than the standard ones. The observations of plant water requirements are based on the results of agrometeorological indices, mostly on the precipitation measurements. The aim of this research was a comparison of the selected agrometeorological indices essential in agriculture (precipitation, reference evapotranspiration, climatic water balance and standardized precipitation index), measured or calculated in the growing season (from April to September) at standard and automatic weather stations and a verification whether the automated station data can be applied without any modifications whatsoever. The investigation was drawing on the data collected between 2000 and 2004 in the Kuyavia region, central Poland. The focus of the research was the interaction between the data series compared. Searching for the ways to adjust the automated to standard 10-day growing season data was an important aspect of the investigation. Despite the different measurement results between both stations compared, great correlation coefficients of the results facilitated the development of mathematical formulas to allow for the use of the automated data series instead of standard records.