辽宁省植被覆盖度时空变化特征及其对气候变化的响应

Spatio-temporal Variation Characteristics of Vegetation Coverage and Its Response to Climate Change in Liaoning Province

基于MODIS-NDVI遥感数据集计算辽宁省2001—2019年植被覆盖度,并结合MODIS土地覆盖产品和辽宁省61个气象观测站气温、降水资料,重点探讨辽宁省5种主要植被类型的植被覆盖度时空变化特征及其对气候变化的响应。结果表明:(1)辽宁省多年平均植被覆盖度为0.48,且呈现“东高西低”的空间分布特征。近19 a来,辽宁省绝大部分地区植被覆盖度呈上升趋势,整体上每10 a增加0.036;主要植被类型作物、草原、落叶阔叶林、多树草原和稀树草原的植被覆盖度均呈显著上升趋势,其中草原增加速率最大,作物增加速率最小。(2)作物的植被覆盖度在暖温带半干旱区与降水存在正相关,与气温存在负相关,而在暖温带半湿润区则与降水和气温均呈现正相关;草原的植被覆盖度对降水响应比气温强烈,而落叶阔叶林、多树草原和稀树草原对气温较为敏感。(3)主要植被类型的植被覆盖度对气温、降水的时滞响应不同。作物和草原在生长季内对上一月降水有时滞响应,而落叶阔叶林、多树草原和稀树草原在生长季末期对上一月气温、降水有时滞响应。

Based on MODIS-NDVI(normalized difference vegetation index)datasets,the vegetation coverage was calculated in Liaoning Province from 2001 to 2019.Combined with land cover products of MODIS and air temperature and precipitation data at 61 meteorological observation stations in Liaoning Province,the spatio-temporal variation characteristics of vegetation coverage of five main types of vegetation were analyzed emphatically,and their responses to temperature and precipitation changes were discussed.The results are as follows:(1)The multi-year mean vegetation coverage was 0.48,and it was high in the east and low in the west of Liaoning Province from 2001 to 2019.The annual vegetation coverage increased in most areas of Liaoning Province in the past 19 years,and it presented an obvious increasing trend with the rate of 0.036 per 10-year as a whole.In additional,the vegetation coverage of five main vegetation types including crop,grassland,deciduous broadleaf forest,woody savanna and savanna increased significantly in Liaoning Province in the past 19 years,and the increasing rate of grassland vegetation coverage was the largest,while for crop vegetation coverage it was the smallest.(2)The vegetation coverage of crop was positively correlated with precipitation and negatively correlated with temperature in semi-arid areas of warm temperate zone in Liaoning Province,while it was positively correlated with precipitation and temperature in semi-humid areas of warm temperate zone.The response of grassland vegetation coverage to precipitation was stronger than temperature,while deciduous broadleaf forest,woody savanna and savanna were more sensitive to temperature.(3)The time lag responses of vegetation coverage with five main vegetation types to temperature and precipitation were different.The response of crop and grassland to precipitation in last month was sensitive during the growth season,while the responses of deciduous broadleaf forest,woody savanna and savanna to previous month’s temperature and precipitation were sensitive at the end stage of growth season.