5:15 PM - 7:15 PM
[MTT38-P04] Development and adjustment of a water vapor DIAL to improve forecast skill of stationary linear mesoscale convective systems
Keywords:Water vapor lidar, DIAL, Stationary linear mesoscale convective systems
Since stationary linear mesoscale convective systems (SLMCS) have a high risk of causing severe heavy rainfall disasters, improving forecasting skills is a pressing social issue. One solution would be to accurately observe the vertical profiles of water vapor concentration in the lower atmosphere because the development of SLMCS is highly sensitive to the low-level moisture profile. Therefore, we have developed a next-generation water vapor lidar that is capable of continuous observation with high precision and high temporal resolution and can be operated at low cost for future operational use.
The water vapor lidar being developed in this study is a diode-laser-based differential absorption lidar (DIAL). Compared to the Raman lidar, the DIAL has a more complicated configuration, but it has many advantages, such as low maintenance frequency, no need for calibration, and the use of a diode laser, which makes the device compact and lightweight. We developed a prototype of the DIAL (e.g., Abo et al., 2018). However, there were some issues, such as the inability to observe high altitudes (only <1 km) during the daytime due to background solar light and requiring technical skills and long hours for the adjustment. Therefore, we have been developing the DIAL to be able to observe up to 3-4 km altitude throughout the day and night, and has improved maintenance workability at the observation site and remote operability.
To increase the observable altitude by effectively observing weakly scattered light from high altitudes, we are currently focusing our efforts on improving the transmittance of the receiving spectrometer and the stability of the transmitted laser output power.
We have been conducting experimental observations since December 2023 at the Meteorological Research Institute in Tsukuba. Although further adjustments are needed, the vertical profiles of water vapor concentration observed with the DIAL fairly agreed with those observed with the radiosonde at Tateno and the JMA Meso-scale Analysis, as well as the Raman lidar installed close to the DIAL.
In the summer of 2025, we will conduct field observations targeting the SLMCS in Nagasaki.
Reference
M. Abo, T. Sakai, P. P. L. Hoai, Y. Shibata, and C. Nagasawa: EPJ Web of Conferences 176 (2018) 04015.
The water vapor lidar being developed in this study is a diode-laser-based differential absorption lidar (DIAL). Compared to the Raman lidar, the DIAL has a more complicated configuration, but it has many advantages, such as low maintenance frequency, no need for calibration, and the use of a diode laser, which makes the device compact and lightweight. We developed a prototype of the DIAL (e.g., Abo et al., 2018). However, there were some issues, such as the inability to observe high altitudes (only <1 km) during the daytime due to background solar light and requiring technical skills and long hours for the adjustment. Therefore, we have been developing the DIAL to be able to observe up to 3-4 km altitude throughout the day and night, and has improved maintenance workability at the observation site and remote operability.
To increase the observable altitude by effectively observing weakly scattered light from high altitudes, we are currently focusing our efforts on improving the transmittance of the receiving spectrometer and the stability of the transmitted laser output power.
We have been conducting experimental observations since December 2023 at the Meteorological Research Institute in Tsukuba. Although further adjustments are needed, the vertical profiles of water vapor concentration observed with the DIAL fairly agreed with those observed with the radiosonde at Tateno and the JMA Meso-scale Analysis, as well as the Raman lidar installed close to the DIAL.
In the summer of 2025, we will conduct field observations targeting the SLMCS in Nagasaki.
Reference
M. Abo, T. Sakai, P. P. L. Hoai, Y. Shibata, and C. Nagasawa: EPJ Web of Conferences 176 (2018) 04015.