VIIRS与MODIS海表面温度产品观测能力对比分析

Observational Capabilities Comparison of Sea Surface Temperature by VIIRS and MODIS

以2015—2016年白天和夜间的VIIRS,MODIS-Terra和MODIS-Aqua 三个红外SST产品为研究对象,探讨了3个红外SST的全球覆盖情况,包括统计全年有效观测天数和每日全球海洋覆盖率,将3个红外SST与Argo浮标在全球范围以及大西洋、印度洋、太平洋进行匹配统计分析,同时对匹配点平均偏差与标准偏差随纬度的变化进行研究,最后将3个红外SST进行交叉比对。结果表明:VIIRS在白天和夜间全年观测到的最大有效观测天数高于MODIS-Terra和MODIS-Aqua,该数据白天观测到的范围最大、全球海洋覆盖率也最高,夜间3个红外SST观测范围和覆盖率差别不大;VIIRS SST产品在全球以及3个大洋统计中数据质量较MODIS-Terra和MODIS-Aqua更接近Argo浮标;3个数据白天的SST平均偏差和标准差随纬度变化除了南北高纬度地区,整体浮动相差不大,VIIRS整体偏差在0 ℃附近,MODIS-Aqua次之,MODIS-Terra大部分都在0 ℃以下。夜间偏差与标准差随纬度变化平缓,在南北半球高纬度地区波动也小于白天。VIIRS白天和夜间SST值都高于其他2个红外SST。白天,VIIRS与MODIS-Aqua的温度值接近;夜间,则与MODIS-Terra的温度值接近。

Sea surface temperature (SST) products from three satellite infrared radiometers of VIIRS, MODIS-Terra and MODIS-Aqua during the daytime and nighttime from 2015 to 2016 were compared in terms of their percentage of valid spatial coverage, uncertainty (through comparison with Argo measurements) and consistency (through inter-comparison). The comparison and analysis were performed on the global basis, with the emphasis on the Atlantic, Indian and Pacific Oceans. The results showed that the maximum number of days with valid satellite observations during daytime and nighttime were higher for VIIRS than MODIS-Terra and MODIS-Aqua. There was little difference in valid coverage in the nighttime, whereas in the daytime VIIRS products were found to have the highest global ocean coverage as compared with MODIS-Terra and MODIS-Aqua. The product accuracy of VIIRS SST was better than MODIS-Terra and MODIS-Aqua. During daytime, the bias and standard deviations of these 3 SST products varied only a little with latitude except the high latitudes areas. The bias of VIIRS fluctuated around 0 ℃, lower than MODIS-Aqua and MODIS-Terra. In the nighttime, the bias and standard deviations of the 3 products were flattened with latitude and their fluctuations in high latitude areas were also less than those in the daytime. VIIRS SST during daytime and nighttime were higher than those of the other two data. The values of VIIRS SST were closer to MODIS-Aqua during daytime while to MODIS-Terra during nighttime.