ISIMIP3a landuse input data

The Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) provides a framework for the collation of a consistent set of climate impact data across sectors and scales. It also provides a unique opportunity for considering interactions between climate change impacts across sectors through consistent scenarios.<br>The ISIMIP3a part of the third simulation round is dedicated to i) impact model evaluation and improvement and ii) detection and attribution of observed impacts according to the framework of IPCC AR5 Working Group II Chapter 18. To this end all simulations are driven by observed socio-economic information combined with either observed (factual) climate data or a detrended (counterfactual) version of the observed climate allowing for the generation of a “no climate change” baseline.<br>This data set provides annual maps of various land use categories. In particular it gives annual maps of both rainfed and irrigated areas of total croplands, of 5 crop categories (C3 annual, C3 perennial, C4 annual, C4 perennial and C3 nitrogen fixing crops) and of 15 crop types/categories (C3 annual disaggregated into: rapeseed, rice, temperate cereals, temperate roots, tropical roots, sunflower, others C3 annual; C3 perennial: (no further disaggregation); C3 nitrogen-fixing disaggregated into: groundnut, pulses, soybean, others C3 nitrogen-fixing; C4 annual disaggregated into: maize, tropical cereals; C4 perennial: sugarcane). Furthermore, maps of pastures, managed rangelands and urban areas are provided.<br>Data is available for the time period: historical (1860-2018).

跨部门影响模型比较计划（Inter-Sectoral Impact Model Intercomparison Project, ISIMIP）提供了一套框架，用于整合不同部门、不同尺度下的一致性气候影响数据集。同时，该计划也为通过统一情景分析跨部门气候变化影响之间的相互作用提供了独特的研究机遇。
第三轮模拟中的ISIMIP3a部分专注于两项任务：i）影响模型的评估与优化；ii）依据政府间气候变化专门委员会第五次评估报告第二工作组第十八章（IPCC AR5 Working Group II Chapter 18）的框架，对已观测到的气候影响进行检测与归因。为此，所有模拟均以观测得到的社会经济信息作为驱动数据，并结合两类气候数据集：一类为实际观测的（事实性）气候数据，另一类为经去趋势处理后的观测气候数据（即反事实气候数据），借此可生成“无气候变化”的基准情景。
本数据集提供了各类土地利用类别的年度空间分布图。具体涵盖：全部耕地的雨养与灌溉区域年度分布图、5类作物分类（C3一年生、C3多年生、C4一年生、C4多年生及C3固氮作物）的年度分布图，以及15种作物类型/类别的年度分布图——其中C3一年生作物进一步细分为油菜、水稻、温带谷物、温带块根作物、热带块根作物、向日葵及其他C3一年生作物；C3多年生作物未做进一步细分；C3固氮作物细分为花生、豆类、大豆及其他C3固氮作物；C4一年生作物细分为玉米、热带谷物；C4多年生作物为甘蔗。此外，数据集还提供了牧场、管理型牧场及城市区域的空间分布图。
数据集的时间覆盖时段为历史时期（1860年-2018年）。