ISLSCP II IGBP DISCover and SiB Land Cover, 1992-1993

This data set describes the geographic distributions of 17 classes of land cover based on the International Geosphere-Biosphere DISCover land cover legend (Loveland and Belward 1997) and the 15 classes of the SiB model processed at the USGS EROS Data Center (EDC). Specifically, the resampled DISCover datasets were derived from the 1km DISCover data set compiled by the USGS. The 1km data sets for each classification scheme were aggregated to 1, 0.5 and 0.25 degree spatial resolutions for this ISLSCP II data collection. Each layer of the aggregated products corresponds to a single DISCover land cover category and the values represent the percentage of the coarse resolution cell (1 degree, etc...)occupied by that land cover category. The dominant class data show the land cover category that occupies the majority of the cell and is derived from the percentage files for each cover type.

The objective of this study was to create a land cover map derived from 1 kilometer AVHRR data using a full year of data (April 1992-March 1993). This thematic map was resampled to 0.25, 0.5 and 1.0 degree grids for the International Satellite Land Surface Climatology Project (ISLSCP) data initiative II. During this re-processing, the original EDC land cover type and fraction maps were adjusted to match the water/land fraction of the ISLSCP II land/water mask. These maps were generated for use by global modelers and others.

This data set is one of the products of the International Satellite Land-Surface Climatology Project, Initiative II (ISLSCP II) data collection which contains 50 global time series data sets for the ten-year period 1986 to 1995. Selected data sets span even longer periods. ISLSCP II is a consistent collection of data sets that were compiled from existing data sources and algorithms, and were designed to satisfy the needs of modelers and investigators of the global carbon, water and energy cycle. The data were acquired from a number of U.S. and international agencies, universities, and institutions. The global data sets were mapped at consistent spatial (1, 0.5 and 0.25 degrees) and temporal (monthly, with meteorological data at finer (e.g., 3-hour)) resolutions and reformatted into a common ASCII format. The data and documentation have undergone two peer reviews.

ISLSCP is one of several projects of Global Energy and Water Cycle Experiment (GEWEX) [http://www.gewex.org/] and has the lead role in addressing land-atmosphere interactions -- process modeling, data retrieval algorithms, field experiment design and execution, and the development of global data sets.

本数据集详述了基于国际地圈-生物圈 DISCover 土地覆盖图例（Loveland and Belward, 1997）以及美国地质调查局 EROS 数据中心（EDC）处理的 SiB 模型中的 15 个类别，对 17 类土地覆盖类型的地理分布进行了描述。具体而言，重采样的 DISCover 数据集源自美国地质调查局编制的 1km DISCover 数据集。每个分类方案下的 1km 数据集被聚合为 1度、0.5度和0.25度空间分辨率的 ISLSCP II 数据集。聚合产品中的每一层均对应于单个 DISCover 土地覆盖类别，而数值表示了粗分辨率格网（如1度等）中该土地覆盖类别所占的百分比。主导类别数据展示了占据单元格大多数面积的土地覆盖类别，并源自每种覆盖类型的百分比文件。研究目标旨在创建一张基于 1 公里 AVHRR 数据，并利用一整年（1992年4月至1993年3月）的数据构建的土地覆盖图。该专题地图被重采样至 0.25度、0.5度和1.0度网格，以适应国际卫星陆地表面气候学计划（ISLSCP）数据计划第二期。在此重新处理过程中，原始 EDC 土地覆盖类型和分数图被调整，以与 ISLSCP II 土地/水域掩膜的陆水比例相匹配。这些地图是为全球模型构建者和其他人使用而制作的。本数据集是国际卫星陆地-地表气候学计划第二期（ISLSCP II）数据集的一部分产品，该数据集包含 1986 年至 1995 年十年期间 50 个全球时间序列数据集，其中选定的数据集跨越了更长的时期。ISLSCP II 是一套一致的数据集集合，这些数据集从现有的数据源和算法中编译而来，旨在满足全球碳、水、能量循环模型构建者和研究者的需求。数据来自多个美国和国际机构、大学和机构。全球数据集在一致的空间（1度、0.5度和0.25度）和时间（月度，气象数据以更精细的分辨率，例如3小时）分辨率下进行映射，并重新格式化为通用的 ASCII 格式。数据及文档已通过两次同行评审。ISLSCP 是全球能量和水循环实验（GEWEX）[http://www.gewex.org/] 的多个项目之一，在解决地表-大气相互作用（过程建模、数据检索算法、现场实验设计和执行以及全球数据集的开发）方面扮演着主导角色。