摘要
采用MODIS的1 km×1 km分辨率数据,以我国黑龙江为研究区,对基于植被指数的植被状态指数(I_(VC))、基于地表温度的温度状态指数(I_(TC))和基于植被指数-地表温度特征空间的植被温度状态指数(I_(VTC))与10 cm,20 cm土壤相对湿度、降水量的关系、3种指数监测结果及其相互关系进行了对比分析。结果表明:I_(VTC)相对于I_(TC),I_(VC)更适于反映土壤湿度的变化,对浅层土壤湿度更加敏感;I_(VTC)相对于I_(TC),I_(VC)对降水更敏感,与监测时段的降水和前期总体降水都密切相关;在生长季早期,I_(VTC)和I_(TC)用于干旱监测的适用性明显优于I_(VC);不同区域间,I_(VTC)的可比性较好,I_(VC)和I_(TC)则较差;I_(VTC)所反映的地表温度信息对干旱的直接指示作用最强,所反映的植被信息对干旱的直接指示作用较弱。
As a frequent natural hazard, drought causes the heaviest damage to daily life and ecological environ ment among all natural disasters. The large scale and dynamic drought monitoring has been frontier and hot topic in the global climate change and food security research. Satellite remote sensing is the main method of obtaining distributed information of the land surface. However, the applicability of a drought monitoring method varies by region and period. So it＇s necessary to inspect and evaluate the drought monitoring method to ensure the validity and accuracy in drought monitoring. Vegetation index based Ivc, land surface temperature based and Surface Temperature-Normalized Difference Vegetation Index space （T,-IaDv space） based are compared to analyze and evaluate their characteristics and applicability in drought monitoring. The MODIS 16-day NDVI （MOD13A2） and 8-day Ts （MOD11A2） provided at 1 km spatial resolution as a gridded level-3 product in the Sinusoidal projection are used, and the Heilongjiang Province, the main food production area in China, is chosen as the study area. The monitoring period is from 9 May to 9 June of the year 2000 to 2008. The correlation between Ivc, Irc, Ivrc and relative soil moisture in 10 cm and 20 cm depth, the correlation between Iw：, Ire, Ivrc and the precipitation in the satellite monitoring period and the cumulative precipitation in the last 1-, 2-, 3-, 4-period time scales, the difference and the relationship between Ivc, Irc, IVTC are analyzed. Significant linear correlation is found between IvTc and the relative soil moisture in 10 cm and 20 cm depth, especially for the 10 cm depth. The correlation between Ivrc and relative soil moisture is obviously better than that between Irc, Ivc and the relative soil moisture. So, it can be judged that Ivrc may mirror the soil moisture better than Ivc and ITC, and is more sensitive to shallow soil moisture. Ivrc is also found linearly correlated with precipitation in current monitoring period, as well as the cumulative precipitation in the last 1-, 2-, 3-, 4-period timescales. The correlations are better than those between Ire, Ivc and pre- cipitation as well as corresponding cumulative precipitation, which show that Ivrc is more sensitive to pre- cipitation than Ivc and Irc, and is closely related to not only current precipitation but also past cumulative precipitation. In the early growing season, Ivrc and Irc are applicable in drought monitoring, while the fractional Ivc cover is too low to monitor drought. It is difficult to compare the drought among different areas with Ivc and Ire, while based on the energy conservation principle, combining the INDV and T, Ivwc can reflect soil moisture better and is comparable in different areas. Furthermore, the land surface temperature implied by IvTc gives more direct hint of drought than the INDV implied especially on the grassland, then in the crop land, brush land and forest land in sequence.
出处
《应用气象学报》
CSCD
北大核心
2011年第2期221-231,共11页
Journal of Applied Meteorological Science
关键词
干旱监测
植被状态指数
温度状态指数
植被温度状态指数
drought monitoring
Vegetation Condition Index
Temperature Condition Index
VegetationTemperature Condition Index
