辽宁省植被NDVI对气候因子的滞后响应研究

LAG RESPONSE OF VEGETATION NDVI TO CLIMATE FACTORS IN LIAONING PROVINCE

关键词:  NDVI  降水  温度  滞后  偏相关分析

Key words:  NDVI  precipitation  temperature  lag  partial correlation analysis

摘要:

目的 分析植被对气候因子的滞后响应，为区域应对气候变化、防灾减灾提供科学理论依据。方法 文章以辽宁省为研究区，利用1998—2013年SPOT/VEGETATION逐旬NDVI数据和气象数据，分析研究区植被NDVI生长变化特点，对植被NDVI与降水、NDVI与温度的滞后关系进行研究，并将另一自变量的影响作为常量，揭示植被生长季不同时间尺度NDVI对降水、温度的滞后天数及其空间分布规律，并与传统分析方法进行比较。结果 5月、6月、7月、8月、9月植被NDVI对降水的滞后天数分别为70d、10d、40d、70d、20d，其中6月和9月植被对降水的响应相较其他时段更为敏感；5月、6月、8月植被NDVI分别与同期、累积10d和同期温度的偏相关关系最大；5月、6月、7月降水对植被的影响均大于温度，8月和9月植被受降水和温度的共同影响；生长季植被对降水的滞后天数在辽宁省西部和东南部等地区较长，对温度的滞后天数在辽宁省北部地区较长。结论 偏相关分析比相关分析更能准确地表达NDVI与气候因子的关系。

Abstract:

This research aims to analyze the lag response of regional vegetation growth to climate factors, so as to provide scientific theoretical basis for regional response to future climate change, disaster prevention and mitigation. Taking Liaoning province as the study area, based on the SPOT/VEGETATION ten-day NDVI data and meteorological data from 1998 to 2013, this research analyzed the growth and dynamic characteristics of vegetation NDVI in Liaoning province, studied the lag relationship between vegetation NDVI and precipitation, vegetation NDVI and temperature. And then taking the effect of another independent variable as a constant, it analyzed the lag days of vegetation NDVI and precipitation, vegetation NDVI and temperature at different time scales during vegetation growing season. In addition, it compared with traditional correlation analysis method and analyzed their differences. The results were showed as follows. In May and August, the lag days of vegetation NDVI and precipitation were both 70 days. The lag days of vegetation NDVI and precipitation were 10, 40 and 20 days respectively in June, July and September. The lag response of vegetation and precipitation in June and September was more sensitive and obvious than it in May, July and August. The partial correlation between vegetation NDVI and the same period temperature was the closest in May and August. In June, the partial correlation between vegetation NDVI and cumulative 10 days temperature was the closest. The effects of precipitation on vegetation growth were all greater than temperature in May, June and July. In August and September, vegetation growth was affected by both the changes of precipitation and temperature. In vegetation growing season, the lag days of vegetation and precipitation were longer in the western and southeastern parts of Liaoning province, and the lag days of vegetation and temperature were longer in the northwestern part of Liaoning province. Research shows, it is found that partial correlation analysis can more accurately express the relationship between NDVI and climate factors than correlation analysis.