摘要
旱情与荒漠化遥感监测有助于了解时空分布特征并及时采取相应措施。以2000-2016年MODIS NDVI和地表反照度(Albedo)数据为基础,构建NDVI-Albedo特征空间,计算荒漠化差值指数(DDI)和植被条件反照度干旱指数(VCADI),利用气象站点实测10cm土壤湿度数据进行相关性验证,并利用DDI和VCADI分别分析17a间陕西省荒漠化和旱情的时空分布特征和规律;其次,利用一元线性回归和变异系数法分析陕西省荒漠化和旱情的变化趋势和稳定性;最后从降雨量、温度等自然因素和人为因素2个方面分析了陕西省荒漠化和旱情变化的原因。结果表明,DDI与土壤湿度呈正相关关系,相关系数为0.49～0.58,且通过了95%显著性检验;VCADI与土壤湿度呈负相关关系,相关系数为-0.36～-0.48,且通过了90%显著性检验,DDI和VCADI分别可作为土地荒漠化和旱情监测指标;陕西省旱情及荒漠化主要分布在关中东北部、西安市周边以及陕北黄土高原地区,呈现为自南向北逐渐加重的趋势;17a间陕西省旱情及荒漠化均呈逐渐减轻和减弱的趋势,旱情及荒漠化减轻和减弱的比例分别为67.94%、81.93%,主要分布在陕北黄土高原地区;DDI和VCADI变异系数<0.4所占比例分别为98.31%和84.05%,旱情及荒漠化呈较稳定状态,受干扰强度较小;DDI、VCADI分别与年降水量、年平均气温之间呈显著相关性的地区占陕西省面积比例均<20%,表明降水量、平均气温不是影响旱情与荒漠化变化的主导因素。
Monitoring of drought and desertification helps to understand the temporal and spatial distribution characteristics of drought and desertification.Desertification index difference calculation in the feature space (DDI) and vegetation albedo (vegetation condition albedo drought index,VCADI) were obtained from NDVI and albedo space based on MODIS data from 2000 to 2016 in Shaanxi province.The field-measured moisture data of 10 cm deep soil from meteorological were used to verify DDI and VCADI.The temporal and spatial distribution characteristics of desertification and drought were assessed by DDI and VCADI.The change trend and stability of drought and desertification were then evaluated using a linear regression analysis and the stability analysis methods.Finally,the change causes of desertification and drought were analyzed from natural factors and human factors.The results showed that there existed a significantly positive correlation between DDI and soil moisture and a negative correlation between VCADI and soil moisture.DDI and VCADI could be used to assess the land desertification and drought monitoring Drought and desertification in Shaanxi province mainly occurred in the northeast Guanzhong,the surrounding areas of Xi'an and the Loess Plateau area of northern Shaanxi.The change trends of drought and desertification gradually increased from south to north.The drought and desertification in Shaanxi Province in 17 years presented a weakened trend and the proportions of drought and desertification decreased 67.94% and 81.93%,respectively,mainly distributed in the Loess Plateau area.The ratio of the coefficient of variation of DDI and VCADI was less than 0.4,and the proportions were 98.31% and 84.05%,respectively,indicating that the drought and desertification were in stable states,and the intensity of the disturbance was smaller.The area ratio of DDI and VCADI with annual precipitation and annual average temperature was less than 20%,which indicated that the precipitation and average temperature were not the dom
作者
岳辉
刘英
YUE Hui;LIU Ying(College of Geomatics,Xi an University of Science and Technology,Xi an 710054,Shaanxi,China)
出处
《西北林学院学报》
CSCD
北大核心
2019年第1期198-205,共8页
Journal of Northwest Forestry University
基金
国家自然科学基金(41401496)
