水稻主要种植在亚洲季风地区，是居民重要的口粮作物之一。由于季风气候、地形和农耕文化等原因，该区域作物种植系统复杂多变。此外，该区域的洪水灾害频发，对水稻等作物的生长造成了严重的影响。随着人口数量剧增和气象灾害频发，水稻种植面积和作物耕种强度也发生了显著变化。但是，大区域长时间序列的水稻种植面积和作物种植制度数据集仍然缺失，这制约了决策者们掌握农业生产变化的真实情况。因此，亚洲季风区的水稻种植面积有什么样的动态特征？作物种植制度的时空分异规律如何？该地区水稻受洪水影响的面积和范围如何？以及洪水对水稻长势有着怎么的影响？等问题需要分析，这些问题的解决对于当地的粮食安全、农田管理和粮食贸易等都具有重要意义。

       根据上述问题，本文选择位于亚洲季风区的主要国家作为研究区，基于田间样点数据和多源遥感数据改进了原有基于物候的水稻种植面积和作物种植制度提取方法，生成了2000年至2020年500米分辨率的水稻种植面积和作物种植制度数据集，并基于Sen斜率和Mann-Kendall检验分析了水稻种植面积和作物强度的空间变化趋势和转移模式。此外，本研究还开发了一套洪水灾害对水稻等作物长势的评估方法和工具。本研究的主要内容和相关结论如下：

       （1）水稻种植面积提取及其时空动态分析。基于改进的方法生成了长时间序列的水稻种植面积数据集。结果表明，使用第三方公开的7613个水稻田间调查样本点显示精度约为0.75；和各地的统计数据及特定地区的高分辨水稻反演产品相比具有较好的空间一致性。近20年水稻种植面积的呈现增加和降低趋势的占比约为4:6，中国东北部和印度西北部的水稻种植面积显著增加（p<0.05），而中国南方部分地区的水稻种植面积显著减少（p<0.05）。

       （2）种植制度识别及其空间转化模式分析。本研究反演的作物和水稻种植制度数据集与部分已公开数据和产品的相关性较好。近20年单季和双季作物的种植在亚洲季风区占主导地位；双季和三季种植面积均显著增加（p<0.05）。约198.1×105公顷的单季种植区转化为双季种植，其主要分布在中国的华北平原和印度北部的恒河平原；此外，约9.5×105公顷的双季种植区转变为三季种植，主要分布在东南亚的湄公河三角洲等地区。然而，中国南方的部分地区的种植制度呈下降趋势。

       （3）水稻的洪水暴露面积变化趋势及洪水对作物长势的影响评估。整体而言上，暴露于非周期性洪水的水稻面积呈不断增加趋势。本文新定义了两种洪水灾害评估指数（植被长势短期损害指数S-VGDI和植被长势长期损害指数L-VGDI），结合洪水淹没数据和作物种植面积数据来评估洪水发生对水稻等作物长势的短期和长期影响，结果表明作物产量损失对两种指数敏感，且两者间存在线性关系。

    Paddy rice is mainly grown in the Asian monsoon region and is one of the important food crops. The crop systems in the study area are complex due to climate, topography, and culture. In addition, the growth of paddy rice and other crops is affected by floods. With the dramatic increase in population and frequent meteorological disasters, the paddy rice planting area (PRA) and cropping intensity (CI) have changed significantly. However, long time series of PRA and CI datasets over large regions are still missing, which constrains policy makers' understanding of changes in agricultural production. Some questions need to be addressed, including what are the dynamic characteristics of PRA in the Asian monsoon region? What are the characteristics of spatial and temporal variation in CI? What are the dynamic characteristics of PRA exposed to flooding? and how to analyze the effect of flooding on paddy rice growth? The generation of PRA and CI datasets is important to ensure food security in the study area.

    Most countries in the Asian monsoon region were selected as the study area. Phenology-based methods for identifying PRA and CI were improved by using field sample points and multi-source remote sensing data in this study. The 500 m resolution PRA and CI datasets from 2000 to 2020 were generated. Then I analyzed the dynamics of rice acreage and crop intensity by using the Sen slope and Mann-Kendall estimator. In addition, a method and tool for assessing flooding on the growth of crops such as paddy rice was designed and developed. The results and conclusions of this study are as follows:

    (1) Paddy rice planting area and its dynamics. A long-time series PRA dataset was generated based on the improved method. The results show that the accuracy of PADDY rice area validation through the publicly available 7613 rice field survey sample points is about 0.75. The spatial consistency of the PRA dataset with official statistics and existing rice map products was high. The ratio of increasing and decreasing trend of paddy rice area was about 4:6 in the last 20 years. The PRA in northeastern China and northwestern India increased significantly (p<0.05). In contrast, the PRA significantly decreased in parts of southern China (p<0.05).

    (2) Cropping intensity and its dynamics. The crop and paddy rice intensity datasets generated in this study correlated well with the available official statistics and map products. Single- and double-cropping intensity are the dominant agricultural systems in the Asian monsoon region. The area under both double and triple cropping increased significantly (p<0.05) from 2001 to 2020. About 198.1 × 105 ha of the single-cropping area was converted to double-cropping, which was mainly distributed in the North China Plain of China and the Ganges Plain of northern India. In addition, about 9.5 × 105 ha of double-cropping areas were converted to triple-cropping, mainly in areas such as the Mekong Delta in Southeast Asia. However, there is a decreasing trend in some areas of southern China.

    (3) Exposure of paddy rice to floods and the effect of floods on crop growth. The area of rice exposed to non-periodic floods in most countries of the Asian monsoon region shows an increasing trend. Two new flood hazard assessment indices (short-term vegetation growth damage index S-VGDI and long-term vegetation growth damage index L-VGDI) were defined. The impact of flooding on the growth of crops such as rice was assessed by integrating flood inundation data and crop acreage data. There is a linear relationship between S-VGDI and L-VGDI and crop yield loss rate.