A minimalistic approach for evapotranspiration estimation using the Prophet model     

A. T. M. Sakiur Rahman  Takahiro Hosono  Ozgur Kisi  Boateng Dennis  A. H. M. Rahmatullah Imon 《水文科学杂志》2020,65(12):1994-2006

ABSTRACT

This study aimed to evaluate the potential of the recently introduced Prophet model for estimating reference evapotranspiration (ETo). A comparative study was conducted for benchmarking the model results with support vector regression (SVR) and temperature-based empirical models (Thornthwaite and Hargreaves) in southern Japan. The performance of the Prophet, SVR and temperature-based empirical models was evaluated by Nash–Sutcliffe efficiency (NSE) and coefficient of determination (R²). The results indicate that temperature-based Prophet and SVR models have greater accuracy than the empirical models. The Prophet model with sole input of relative humidity, sunshine hours or windspeed showed acceptable accuracy (NSE > 0.80; R² > 0.80), while SVR models with similar inputs showed greater errors. Accuracy improved with increasing number of input parameters, giving excellent performance (NSE > 0.95; R² > 0.95) with all input parameters. Hence, the Prophet model is a new promising approach for modelling ETo with limited input variables.  相似文献   

Mapping runoff generating areas using AGNPS-VSA model     

Kishor Panjabi  Pradeep Goel  Prasad Daggupati  Narayan Kumar Shrestha  Rituraj Shukla 《水文科学杂志》2020,65(13):2224-2232

ABSTRACT

In humid regions, surface runoff is often generated by saturation-excess runoff mechanisms from relatively small variable source areas (VSAs). However, the majority of the current hydrologic models are based on infiltration-excess mechanisms. In this study, the AGricultural Non-Point Source Pollution (AGNPS) model was used to integrate the VSA concept using topographic wetness index (TWI). Both the original and AGNPS-VSA models were evaluated for a small agricultural field in Ontario, Canada. The results indicate that the AGNPS-VSA model performed better than original model. The AGNPS-VSA model predicted that only the saturated portion of the field with higher TWI values produced runoff, whereas the original AGNPS model showed uniform hydrologic response from the entire field. The results of this study are important for accurately mapping the locations of VSAs. This new model could be a powerful tool in identifying critical source areas for applying targeted best management practices to minimize pollutant loads to receiving waters.  相似文献   

Improvement of spatial interpolation accuracy of daily maximum air temperature in urban areas using a stacking ensemble technique     

Dongjin Cho  Cheolhee Yoo  Yeonsu Lee  Jaese Lee 《地理信息系统科学与遥感》2020,57(5):633-649

ABSTRACT

The reliable and robust monitoring of air temperature distribution is essential for urban thermal environmental analysis. In this study, a stacking ensemble model consisting of multi-linear regression (MLR), support vector regression (SVR), and random forest (RF) optimized by the SVR is proposed to interpolate the daily maximum air temperature (T_max) during summertime in a mega urban area. A total of 10 geographic variables, including the clear-sky averaged land surface temperature and the normalized difference vegetation index, were used as input variables. The stacking model was compared to Cokriging, three individual data-driven methods, and a simple average ensemble model, all through leave-one-station-out cross validation. The stacking model showed the best performance by improving the generalizability of the individual models and mitigating the sensitivity to the extreme daily T_max. This study demonstrates that the stacking ensemble method can improve the accuracy of spatial interpolation of environmental variables in various research fields.  相似文献   

Detecting patterns of climate change in long-term forecasts of marine environmental parameters     

Gianpaolo Coro  Pasquale Pagano  Anton Ellenbroek 《International Journal of Digital Earth》2020,13(5):567-585

ABSTRACT

Forecasting environmental parameters in the distant future requires complex modelling and large computational resources. Due to the sensitivity and complexity of forecast models, long-term parameter forecasts (e.g. up to 2100) are uncommon and only produced by a few organisations, in heterogeneous formats and based on different assumptions of greenhouse gases emissions. However, data mining techniques can be used to coerce the data to a uniform time and spatial representation, which facilitates their use in many applications. In this paper, streams of big data coming from AquaMaps and NASA collections of 126 long-term forecasts of nine types of environmental parameters are processed through a cloud computing platform in order to (i) standardise and harmonise the data representations, (ii) produce intermediate scenarios and new informative parameters, and (iii) align all sets on a common time and spatial resolution. Time series cross-correlation applied to these aligned datasets reveals patterns of climate change and similarities between parameter trends in 10 marine areas. Our results highlight that (i) the Mediterranean Sea may have a standalone ‘response’ to climate change with respect to other areas, (ii) the Poles are most representative of global forecasted change, and (iii) the trends are generally alarming for most oceans.  相似文献   

Essential variables for air quality estimation     

Andrii Shelestov  Tatiana Borisova  Olena Turos  Gennadi Milinevsky  Igor Gomilko 《International Journal of Digital Earth》2020,13(2):278-298

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夏季亚洲对流层中上层温度年际变率的预测水平评估及其在我国东部降水预测中的应用     

张丽霞  周天军 《大气科学》2020,44(1):150-167

夏季亚洲对流层温度异常与中国东部夏季降水紧密相关并可能作为降水的有效预报因子。基于欧盟ENSEMBLES计划的季节预测试验耦合模式每年5月1日开始的回报试验，分析了其对1960～2005年夏季亚洲对流层中上层温度（以200～500 hPa厚度替代，简称对流层温度）年际变率的预测结果，发现模式集合平均对夏季亚洲对流层温度年际变率具有较高的预报技巧，可以合理回报其前两个EOF（Empirical Orthogonal Function）主导模态（EOF1、EOF2），只是未能回报出EOF2高纬度的温度异常，模式集合平均预测的第一模态主成分（PC1）和第二模态主成分（PC2）与再分析资料的时间相关系数分别达到0.63和0.77。再分析资料中前两个EOF模态分别由ENSO（El Ni?o–Southern Oscillation）发展年印度夏季降水异常所激发的丝绸之路遥相关波列和ENSO衰减年西北太平洋夏季降水异常对应的太平洋—日本遥相关波列导致。ENSEMBLES计划可以合理预测出相应的海温异常及遥相关波列，进而合理预测出前两个EOF模态。对流层温度PC1和PC2分别表征了欧亚大陆与周围海洋之间的纬向和经向热力对比异常，模式对由PC1的预报技巧远高于前人定义的纬向热力对比的东亚夏季风指数，对前人定义的经向热力对比指数的预测技巧与PC2相当。将PC1和前人定义的经向热力对比指数作为预报因子，建立了中国夏季降水的动力—统计降尺度预测模型，交叉检验的结果表明该预报模型显著提高了东北和长江流域上游夏季降水的预报技巧。本文提出的亚洲对流层温度年际变率的EOF1及PC1，既能较好表征纬向热力对比与中国东部夏季降水显著相关，又能被模式合理预测，可以作为我国中高纬度地区，特别是东北地区降水的重要预测因子之一。  相似文献   

基于昆明市精细化GIS的天气雷达标准格式基数据应用     

甄廷忠  江龙  段燕楠  王菲 《气象科技》2020,48(1):59-67

以国家地理信息公共服务平台、云南数字乡村、Mapinfo公共数据为数据源,在C#开发环境下实现了精细到乡镇、公路、行政村、自然村的昆明市精细化地理信息系统(GIS)的自主研发,解决了基层气象部门缺乏精细化GIS的难题。介绍了标准格式基数据的解析、成图过程及注意事项,在全国范围内较早实现了天气雷达标准格式基数据在基层气象部门的业务应用。在业务应用过程中,发现了CC天气雷达标准格式早期基数据存在回波强度严重减弱的问题;昆明市精细化GIS与昆明天气雷达回波图的融合应用,可以精确定位雷达强回波区,对精细化气象服务具有指导作用,提高了强天气精细化预警能力、短时临近精细化预报能力和防灾减灾能力。  相似文献   

茶叶寒冻害天气指数保险设计     

汪春辉  陈治杰  陈家金  赵伯听 《气象科技》2020,48(1):141-146

以茶叶萌芽至展叶期寒冻害为突破口,利用1987—2016年福建省泉州市安溪县17个自动气象站2—4月的逐日气象数据及安溪各茶树种植区产量数据,确定茶叶寒冻害的天气指数保险气象指标,分析日极端最低气温与茶叶减产率的关系,建立了茶叶寒冻害指数模型。计算安溪不同区域茶叶种植区不同等级寒冻害的发生概率,应用纯保费率方法厘定了保险费率,并根据福建省政策性农业保险的实际情况,制定茶叶不同区域种植区寒冻害指数保险触发条件、赔付标准,设计了安溪县茶叶寒冻害天气指数保险合同。设计的茶叶寒冻害天气指数保险产品以客观气象数据作为定损依据,可以为茶农提供一种有效的风险转嫁方式,也为保险公司增加新险种提供了技术支撑。  相似文献   

湖陆风效应为主导的地面弱风预报方法     

苗青建  矫东霖  陈江云  徐唱  吴思江  罗超  刘杰  武越  严鹏 《沙漠与绿洲气象(新疆气象)》2020,14(1):56-62

对博斯腾湖东南陆地风场数据进行计算,结合湖陆风效应初步建立夏半年各月风场日变化模型,得出风场日变化的4个典型时段。结果表明,区域测站一致性系数和风场有较好的对应关系,一致性系数小于50说明风向不稳定且风速较小,一致性系数大于80说明风向趋于稳定且风速一般较大,弱风时段主要出现在日出日落前后,且具有2h左右的持续时间。该方法为该地区弱风时段预报提供了思路,在稳定的高压脊形势下效果尤为明显。  相似文献   

亚洲中部干旱气候研究综述与机理分析     

戴新刚  汪萍 《沙漠与绿洲气象(新疆气象)》2020,14(1):1-12

综述了亚洲中部干旱气候若干研究进展,并对亚洲中纬度干旱区形成机理进行了深入分析。依据大尺度气候分类法将全球陆地划分为季风、地中海及西风带气候区,分别对应于年内季节循环中多雨—高温的同位相、反位相及不相关等类型水—热配置特征。亚洲中部干旱区南北部分属地中海和西风带气候区,其不同水—热位相配置又对应于不同的水汽通量及其散度等特征。研究揭示了欧亚大陆中部干旱区形成于降水不足且季节性水—热配置不当,起因于大气环流平均槽脊季节变化引起的大气动力—热力配置,其根源是海陆热力差异及大地形对大气环流强迫的结果。本文还讨论了季风区与非季风区之间平均气流水汽散度的季节性互动,以及行星尺度上不同气候区之间平均气流与瞬变涡动水汽散度之间的配置等问题。  相似文献