17:15 〜 18:30
[ACG36-P06] Long Term Analysis of TPW (total precipitable water vapor) product
キーワード：AMSR-E、AMSR2、可降水量、水蒸気、長期解析
Global climate and water cycle changes become social issues that have attracted more attention in recent years. It is critical to observe geophysical parameters (essential climate variables) on a long-term, continuous, and global scale to understand the global climate and water cycle changes mechanism. The amount of water vapor in the atmosphere is vital information for forecasting meteorological phenomena such as heavy rains and typhoons and understanding global climate and water cycle changes.
JAXA's Advanced Microwave Scanning Radiometers (AMSR-E and AMSR2) continuously provide various hydrological parameters, including Total Precipitable Water (TPW) over ocean, since June 2002. The next generation sensor AMSR3 will be on the Global Observing Satellite for Greenhouse gases and Water cycle (GOSAT-GW), and the launch is scheduled for 2023. Since the sensor specifications and observation conditions of AMSR-E and AMSR2 are almost the same, it is possible to generate a consistent long-term data set for AMSR-E and AMSR2 (and AMSR3 in the future). However, there is an approximately 8-month data missing period between the AMSR-E and AMSR2, and JAXA's TPW product shows different trends before and after the gap. It is uncertain if they are the actual TPW trend: the difference might be due to the sensors' calibration in AMSR-E and AMSR2.
In this study, to clarify the cause of the gap between AMSR-E and AMSR2, we analyzed not only TPW products of JAXA but also that of Remote Sensing Systems (RSS). RSS performs retrieval TPW from AMSR brightness temperature data with its own algorithm. We analyzed the long-term trend of the TPW products of AMSR-E and AMSR2 from 2002 to the present. Fig. a shows the long-term trend analysis of TPW, and we compares in-situ observations such as radiosonde and ground-based GPS occultation observations (Fig. b). These analyses allow us to verify the accuracy of the respective TPW products for JAXA and RSS. The comparison is analyzed by varying region, QC flag, sea surface temperature, and other conditions (Fig. c). We discuss each product's trend's characteristics and the main factors of the difference between JAXA and RSS products.
JAXA's Advanced Microwave Scanning Radiometers (AMSR-E and AMSR2) continuously provide various hydrological parameters, including Total Precipitable Water (TPW) over ocean, since June 2002. The next generation sensor AMSR3 will be on the Global Observing Satellite for Greenhouse gases and Water cycle (GOSAT-GW), and the launch is scheduled for 2023. Since the sensor specifications and observation conditions of AMSR-E and AMSR2 are almost the same, it is possible to generate a consistent long-term data set for AMSR-E and AMSR2 (and AMSR3 in the future). However, there is an approximately 8-month data missing period between the AMSR-E and AMSR2, and JAXA's TPW product shows different trends before and after the gap. It is uncertain if they are the actual TPW trend: the difference might be due to the sensors' calibration in AMSR-E and AMSR2.
In this study, to clarify the cause of the gap between AMSR-E and AMSR2, we analyzed not only TPW products of JAXA but also that of Remote Sensing Systems (RSS). RSS performs retrieval TPW from AMSR brightness temperature data with its own algorithm. We analyzed the long-term trend of the TPW products of AMSR-E and AMSR2 from 2002 to the present. Fig. a shows the long-term trend analysis of TPW, and we compares in-situ observations such as radiosonde and ground-based GPS occultation observations (Fig. b). These analyses allow us to verify the accuracy of the respective TPW products for JAXA and RSS. The comparison is analyzed by varying region, QC flag, sea surface temperature, and other conditions (Fig. c). We discuss each product's trend's characteristics and the main factors of the difference between JAXA and RSS products.