[Research on the spectral feature and identification of the surface vegetation stressed by stored CO2 underground leakage].

With the global climate warming, reducing greenhouse gas emissions becomes a focused problem for the world. The carbon capture and storage (CCS) techniques could mitigate CO2 into atmosphere, but there is a risk in case that the CO2 leaks from underground. The objective of this paper is to study the chlorophyll contents (SPAD value), relative water contents (RWC) and leaf spectra changing features of beetroot under CO2 leakage stress through field experiment. The result shows that the chlorophyll contents and RWC of beetroot under CO2 leakage stress become lower than the control beetroot', and the leaf reflectance increases in the 550 nm region and decreases in the 680nm region. A new vegetation index (R550/R680) was designed for identifying beetroot under CO2 leakage stress, and the result indicates that the vegetation index R550/R680 could identify the beetroots after CO2 leakage for 7 days. The index has strong sensitivity, stability and identification for monitoring the beetroots under CO2 stress. The result of this paper has very important meaning and application values for selecting spots of CCS project, monitoring and evaluating land-surface ecology under CO2 stress and monitoring the leakage spots by using remote sensing.

[Research of coupling effects among various water quality components].

Based on aquatic optics Monte Carlo hyperspectral simulation, the interactions between spectral characteristics of chlorophyll a, total suspended matter (TSM) and colored dissolved organic matter (CDOM) were discussed. The result shows that the nonlinear and spectrally varying interactions between different water components are extremely highly asymmetric. The existing of chlorophyll a and CDOM has little effects on the characteristic wavebands selection and information retrieval of TSM, while the effects of TSM on chlorophyll a are obvious. With the stepwise additions of TSM, the response of chlorophyll a to its concentration becomes weak. When the concentration of TSM increases to a certain degree, the spectral response of chlorophyll a concentration will disappear. Even at the sensitivity waveband of chlorophyll a such as 670 nm, when the TSM is in high concentration, the spectral reflectance will not change with chlorophyll a concentration, which lead to difficulty to extract the chlorophyll a concentration in turbid water dominated by suspended matter. The existing of CDOM causes the blue and green band ratio algorithm to fail when the chlorophyll a is in middle to high concentration. The spectral effects on CDOM of the water body dominated by TSM are more obvious than that dominated by chlorophyll a. There are strong inhibition effects of TSM on the CDOM spectral properties in the short bands. The research results can provide theoretical basis for characteristic waveband selection, the application scope of water component concentration inversion algorithm and the waveband setting for case 2 water remote sensing.