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根据水体和冰在微波波段介电特性的显著差异,提出了一个利用被动微波遥感数据监测青海湖湖冰的封冻与解冻日期的方法.利用青海湖水文站的观测和MODIS反射率数据对监测结果进行验证,表明被动微波遥感亮度温度数据可以准确监测湖冰,不确定因素主要来自卫星观测的重复周期.对青海湖湖冰的长期监测结果表明:1978~2006年间湖冰持续时间减少了14~15d,其中冻结日期推迟了大约4d,而解冻日期提前了大约10d.湖冰持续日数、封冻日期和解冻日期与年内月平均气温多元回归分析表明,在0.05的置信水平下,相关性分别为0.83,0.66和0.89,因此湖冰持续日数的年际变化可以反映青海湖地区的气候变化.
Based on the significant difference between the dielectric properties of water and ice in the microwave band, a method of using passive microwave remote sensing data to monitor the freezing and thawing dates of Qinghai Lake ice was proposed. Using the observation data of Qinghai Lake hydrological station and MODIS reflectance data, The results show that the data of passive microwave remote sensing brightness temperature can accurately monitor the ice and ice, the uncertainties mainly come from the repeated observation period of the satellite.The long-term monitoring of the ice in Qinghai Lake shows that the duration of ice from 1978 to 2006 is reduced by 14 ~ 15d, the freezing date was postponed for about 4 days, and the thawing date was advanced by about 10 days. Multivariate regression analysis of the number of days of frozen ice, freezing date, thawing date and monthly mean temperature showed that at the confidence level of 0.05, the correlations were 0.83, 0.66 and 0.89. Therefore, the interannual change of lake ice duration can reflect the climate change in Qinghai Lake area.