Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Average Annual Daily Maximum Temperature, 2002

This data set represents the average monthly maximum temperature in Celsius multiplied by 100 for 2002 compiled for every catchment of NHDPlus for the conterminous United States. The source data were the Near-Real-Time High-Resolution Monthly Average Maximum/Minimum Temperature for the Conterminous United States for 2002 raster dataset produced by the Spatial Climate Analysis Service at Oregon State University.

The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States.

The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus Production Units 4, 5, 7 and 9. MRB4, covering the Missouri River basins, contains NHDPlus Production Units 10-lower and 10-upper. MRB5, covering the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf River basins, contains NHDPlus Production Units 8, 11 and 12. MRB6, covering the Rio Grande, Colorado and Great Basin River basins, contains NHDPlus Production Units 13, 14, 15 and 16. MRB7, covering the Pacific Northwest River basins, contains NHDPlus Production Unit 17. MRB8, covering California River basins, contains NHDPlus Production Unit 18.

本数据集针对美国本土范围内所有NHDPlus（National Hydrography Dataset Plus）汇水区，提供2002年的月均最高气温数据（数据单位为摄氏度×100）。其源数据为俄勒冈州立大学空间气候分析服务中心制作的2002年美国本土近实时高分辨率月均最高/最低气温栅格数据集。

NHDPlus V1.1是一套可直接投入应用的集成地理空间数据集，整合了全国水文数据集（National Hydrography Dataset, NHD）与全国高程数据集（National Elevation Dataset, NED）的诸多优势特性。该数据集包含基于1:10万比例尺NHD构建的河网、优化后的网络拓扑、命名规范以及增值属性（VAAs）。此外，NHDPlus还包含基于高程生成的汇水区（排水区），其制作采用了最初在新英格兰地区广泛应用的排水强化技术，即所谓的“新英格兰方法”。该技术首先对1:10万比例尺NHD数据进行“烧入”处理，并在可行时利用全国流域边界数据集（WBD）构建边界墙；由此得到的改进型数字高程模型（HydroDEM）可用于生成与NHD及WBD匹配一致的水文衍生产品。过去两年间，来自美国地质调查局（USGS）、美国环境保护署（USEPA）及承包商的跨学科团队研究表明，该方法通过自动化流程可生成最高质量的NHD汇水区（USEPA, 2007）。NHDPlus数据集按照覆盖美国本土的18个生产单元进行组织。

NHDPlus V1.1数据按照美国地质调查局的主要流域（MRBs, Crawford等，2006）进行分组：
MRB1覆盖新英格兰及中大西洋流域，包含NHDPlus生产单元1与2；
MRB2覆盖南大西洋-墨西哥湾和田纳西河流域，包含NHDPlus生产单元3与6；
MRB3覆盖五大湖、俄亥俄河、上密西西比河以及苏里斯-雷德-雷尼河流域，包含NHDPlus生产单元4、5、7与9；
MRB4覆盖密苏里河流域，包含NHDPlus生产单元10-下与10-上；
MRB5覆盖下密西西比河、阿肯色-怀特-雷德河以及德克萨斯-墨西哥湾流域，包含NHDPlus生产单元8、11与12；
MRB6覆盖里奥格兰德、科罗拉多河以及大盆地流域，包含NHDPlus生产单元13、14、15与16；
MRB7覆盖太平洋西北河流域，包含NHDPlus生产单元17；
MRB8覆盖加利福尼亚河流域，包含NHDPlus生产单元18。