The Sanjiang Plain is located in the northern part of the mid-temperate zone of China. In recent years, climate warming and cultivated land use have been changing significantly. So it is of great significance in protecting food security and stability to analyze responses of cultivated land use to regional climate change. As cultivated land is a kind of artificial vegetation, its NDVI value reflects certain crop information, like growth and yield. Therefore, by analyzing impacts of climate factors on cultivated land NDVI, information relevant to response of regional cultivated land use to climate change can be obtained.[Objective] Based on the data of cultivated land use, ten-day climatic data, and ten-day normalized difference vegetation indexes (NDVI) of the Sanjiang Plain during the farming period (May~September) of the years from 2000 to 2015, temporal changes in climatic factors and spatial variation of NDVI of the cultivated land were obtained through analysis and furthermore, information about delayed response of cultivated land NDVI to regional climate change was acquired.[Method] In this research, methods, like variation coefficient analysis, trend coefficient analysis and time-delay cross correlation analysis were adopted.[Result] Results show:(1)The interannual variability of temperature was more stable than that of precipitation during the farming period of the Sanjiang Plain, while the intermonthly variabilities of the two tended to be more regular; (2)The cultivated land NDVI did vary much between years, with the vegetation coverage being the highest in September; spatial variation of the cultivated land NDVI during the 16 years exhibited a trend of being low-unstable-increasing in value, representative in the western part of the region and being high-stable-decreasing in value, representative in the eastern part; (3)Maximum unbiased correlation coefficients of the ten-day NDVIs and ten-day mean temperatures of the cultivated land varied mostly in the range between 0.931 and 0.992, and delayed response was observed for 2 ten-day periods. Maximum unbiased correlation coefficients of the ten-day NDVI and ten-day precipitation of the cultivated land varied in the range between 0.778 and 0.927, and delayed response was observed for 1 ten-day period only. The cultivated land NDVI of the Sanjiang Plain, except for Fuyuan County, Raohe County and Tongjiang City, responded more slowly to air temperature than to precipitation. The cultivated land NDVI responded quite slowly to regional climate change in Jiamusi City and Shuangyashan City, while it did rather quickly in Mishan City, Baoqing County, and Hulin City. Moreover, it responded faster to change in air temperature and slower to change in precipitation in Fuyuan County and Muling City; and (4) The maximum unbiased correlation coefficients of dry land ten-day NDVI and ten-day mean temperature were both 0.942, and that of the paddy field's was 0.962. Delayed response of NDVI to mean temperature in dry land was observed for 2.026 ten-day periods, and that in paddy field for 1.633 ten-day period. The mean maximum unbiased correlation coefficient between ten-day NDVI and ten-day precipitation was 0.809 in dry land, and 0.765 in paddy field, and the mean time lag of NDVI to precipitation was 1.323 ten-day period in dry land, and 1.045 ten-day periods in paddy field.[Conclusion] Change in regional temperature impacts cultivated land NDVI more than change in precipitation does. The lag of NDVI responding to air temperature of cultivated land is longer than that to precipitation in most counties. Temperature is a major factor affecting regional paddy field NDVI; the lag of dry land NDVI responding to regional climate change is longer than that of paddy field's. The findings in the research may provide a scientific basis for guiding farming production of the region to cope with climate change and ensure food security.
张露洋,雷国平,郭一洋,路中.三江平原耕地归一化植被指数对气候因子的时滞响应[J].土壤学报,2021,58(2):526-536. DOI:10.11766/trxb201910240413 ZHANG Luyang, LEI Guoping, GUO Yiyang, LU Zhong. Delayed Responses of Normalized Difference Vegetation Index of Cultivated Land to Climatic Factors in Sanjiang Plain[J]. Acta Pedologica Sinica,2021,58(2):526-536.复制