The excessive use of synthetic nitrogen (N) for Chinese wheat production results in high loss of reactive N (Nr; all forms of N except N2) into the environment, causing serious environmental issues. Quantifying Nr loss and spatial variations therein is vital to optimize N management and mitigate losses. However, accurate, high spatial resolution estimations of Nr loss from wheat production are lacking due to the limitations of data generation and estimation methods. Here, we applied the random forest (RF) algorithm to bottom-up N application rate data, obtained through a survey of millions of farmers, to estimate the Nr loss from wheat production in 2014. The results showed that the average total Nr loss was 52.5 kg N ha-1 (range: 4.6–157.8 kg N ha-1), which accounts for 26.1% of the total N applied. The hotspots for high Nr loss are the same as those for high applied N, including northwestern Xinjiang, central-southern Hebei, Shandong, central-northern Jiangsu, and Hubei. Our database could guide regional N management and be used in conjunction with biogeochemical models.
Xingshuai TIAN
Based on AVHRR-CDR SR products, a daily cloud-free snow cover extent dataset with a spatial resolution of 5 km from 1981 to 2019 was prepared by using decision tree classification method. Each HDF4 file contains 18 data elements, including data value, data start date, longitude and latitude, etc. At the same time, to quickly preview the snow distribution, the daily file contains the snow area thumbnail, which is stored in JPG format. This data set will be continuously supplemented and improved according to the real-time satellite remote sensing data and algorithm update (up to may 2019), and will be fully open and shared.
HAO Xiaohua
本数据集提供了中国八种土地覆被类型(森林、草灌、耕地、湿地、水体、建设用地、裸地、永久冰雪)占比数据,空间分辨率为1km,时间序列为2001-2018年。通过加权一致性分析的方法融合了CCI-LC和MCD12Q1数据,生产了China-LCFMCD-CCI(中国土地覆被占比数据),经数据验证和不确定性计算,本数据集具有较好的可信度和较低的不确定性。数据可使用ArcGIS, QGIS, ENVI, and ERDAS等软件打开,可为中国土地覆被变化的研究提供数据基础,对于土地覆被数据产品的应用具有重要意义
刘焱序, 王慧, 王奕佳, 蔡利平
“水权框架下黑河流域治理的水文-生态-经济过程耦合与演化”(91125018)项目数据汇交3-黑河流域近期治理规划(水利部,2001) 1.数据概述:黑河流域2001年开始实施的治理规划 2.数据内容:规划公开本
王忠静
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