Spatio-temporal distribution of rice phenology and cropping systems in the Mekong Delta with special reference to the seasonal water flow of the Mekong and Bassac rivers
Spatio-temporal distribution of rice phenology and cropping systems in the Mekong Delta with special reference to the seasonal water flow of the Mekong and Bassac rivers
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DOI：
10.1016/j.rse.2005.09.007
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发表时间：
2006-01-15
影响因子：
13.5
通讯作者：
Yokozawa, M
中科院分区：
文献类型：
--
作者：
Sakamoto, T;Nguyen, NV;Yokozawa, M
利用多时相中分辨率成像光谱仪（MODIS）数据，估算了2002年和2003年湄公河三角洲水稻抽穗期和种植制度与水资源季节变化的空间分布。我们改进了用于确定作物物候的基于小波的滤波器（WFCP），并开发了用于评估种植系统空间分布的基于小波的滤波器（WFCS），以解释MODIS时间序列数据，以确定水稻物候的空间分布和各种水稻种植系统从季节性增强植被指数（EVI）数据。研究结果符合湄公河三角洲种植系统的物理特征，随着时间的推移，在响应本地化和季节性变化的水资源。其中一个例子是湄公河三角洲上游在旱季普遍采用的双灌溉水稻种植制度，以避免随后的洪水造成的损害。由于缺乏适当的灌溉水，旱季沿海地区咸水入侵，限制了旱季种植，这意味着雨季采用双季和单季水稻种植制度。湄公河三角洲中部地区位于洪水易发区和盐碱入侵区之间，采用了三重灌溉的水稻种植系统。对2002 - 2003年水稻种植制度的年际变化分析表明，三熟制水稻向洪涝和盐碱入侵区扩展。这一扩大表明，通过改进耕作技术和改善土地管理，采取措施限制洪水和盐碱侵入的程度。2003年湄公河三角洲上游的抽穗期比2002年提前约20 - 30天。其原因可能是2002年的洪水径流量比2001年减少，以及政府执行了早播旱季作物的政策。随后对MODIS数据的分析证实，湄公河三角洲水稻种植系统的空间分布与河流径流状况的季节变化密切相关。(C)2005年爱思唯尔公司All rights reserved.
Multi-temporal Moderate Resolution Imaging Spectroradiometer (MODIS) data was used to estimate the spatial distribution of heading date and rice-cropping system employed in the Mekong Delta relative to seasonal changes in water resources in 2002 and 2003. We improved a Wavelet-based Filter for determining Crop Phenology (WFCP) and developed a Wavelet-based Filter for evaluating the spatial distribution of Cropping Systems (WFCS) to the interpretation of MODIS time-series data to determine the spatial distribution of rice phenology and various rice-cropping systems from the seasonal Enhanced Vegetation Index (EVI) data. The findings correspond well the physical characteristics of the cropping system in the Mekong Delta, which have changed over time in response to localized and seasonal changes in water resources. One such example is the double-irrigated rice-cropping system commonly employed in the upper Mekong Delta in the dry season to avoid damage due to the subsequent floods. The shortage of suitable irrigation water and intrusion of saline water in the coastal regions during the dry season has constrained the practice dry-season cropping and has meant that the double- and single-rainfed rice-cropping systems are employed in the rainy season. A triple-irrigated rice-cropping system is used in the central part of the Mekong Delta which is located midway between the flood-prone and salinity intrusion areas. Analysis of annual changes in the rice cropping systems between 2002 and 2003 showed that the triple-cropped rice expanded to the flood- and salinity-intrusion areas. This expansion indicates that the implementation of measures to limit the extent of flooding and salinity intrusion by improved farming technologies and improvements in land management. The heading dates in the upper Mekong Delta in 2003 were earlier than in 2002 by approximately 20 to 30 days. The reasons for this would be due to decreased flood runoff in 2002 compared to 2001, and implementation of government policies regarding early sowing of dry-season crops. Subsequent analysis of the MODIS data confirmed that the spatial distribution of rice-cropping systems was closely related to seasonal changes in river runoff regime in the Mekong Delta. (C) 2005 Elsevier Inc. All rights reserved.