RESUMO
Vegetation canopy water content (VCWC) has widespread utility in agriculture, ecology and hydrology. Based on the PROSAIL model, a novel model for quantitative inversion of vegetation canopy water content using Hyperion hyperspectral data was explored. Firstly, characteristics of vegetation canopy reflection were investigated with the PROSAIL radiative transfer model, and it was showed that the first derivative at the right slope (980 - 1 070 nm) of the 970 nm water absorption feature (D98-1 070) was closely related to VCWC, and determination coefficient reached to 0.96. Then, bands 983, 993, 1 003, 1 013, 1 023, 1 033, 1 043, 1 053 and 1 063 nm of Hyperion data were selected to calculate D980-1 070, and VCWC was estimated using the proposed method. Finally, the retrieval result was verified using field measured data in Yingke oasis of the Heihe basin. It indicated that the mean relative error was 12.5%, RMSE was within 0.1 kg x m(-2) and the proposed model was practical and reliable. This study provides a more efficient way for obtaining VCWC of large area.
Assuntos
Monitoramento Ambiental , Plantas , Análise Espectral , Água , Agricultura , Modelos Teóricos , Análise de RegressãoRESUMO
OBJECTIVE: To evaluate the implementation and effectiveness of comprehensive control measures of schistosomiasis in Caidian District, Wuhan City. METHODS: The data of implementation of the schistosomiasis control measures in Caidian District was collected and analyzed statistically. RESULTS: The number of Oncomelania hupensis snail environments and snail area decreased from 213 sites and 223.47 hm2 in 2003 to 59 sites and 51.20 hm2 in 2013, with the decreasing rate of 72.30% and 77.09%, respectively. The infection rate of schistosomiasis of human decreased from 1.58% in 2006 to 0.24% in 2013, with the decreasing rate of 84.81%. The positive rate of stool tests of cattle was 2.19% in 2006 while it was 0 in 2013. CONCLUSION: The comprehensive control measures of schistosomiasis are effective.