Impact of assimilating GNSS Tropospheric Gradients along with Zenith Total Delays for Severe Weather Prediction

The Global Navigation Satellite System (GNSS) tropospheric gradients offer valuable information about how moisture is distributed in the atmosphere. These gradients are determined by studying variations in how the atmosphere refracts signals, which are measured based on delays from satellites positioned at different angles. Zus et al. (2023) developed a tropospheric gradient operator that has been added to the Weather Research and Forecasting (WRF) model. Thundathil et al. (2024) conducted several impact experiments showing promising improvements using this operator.

We are currently integrating data from MPG-NET, a multi-purpose GNSS station network in the Swiss Alps (Aichinger-Rosenberger, Matthias, et al., 2023), and data from the Swabian MOSES (Modular Observation Solutions for Earth Systems) field campaign of 2023, which focused on extreme hydro-meteorological events in southwestern Germany. As part of this work, we are simulating the occurrence of hailstorm activity in July 2023. We plan to present initial results from the assimilation of ZTD and gradients for this event.

References:

Zus, F., Thundathil, R., Dick, G., & Wickert, J. (2023). Fast Observation Operator for Global Navigation Satellite System Tropospheric Gradients. Remote Sensing, 15(21), 5114.

Thundathil, R., Zus, F., Dick, G., & Wickert, J. (2024). Assimilation of GNSS tropospheric gradients into the Weather Research and Forecasting (WRF) model version 4.4. 1. Geoscientific Model Development, 17(9), 3599-3616.

Aichinger-Rosenberger, M., Wolf, A., Senn, C., Hohensinn, R., Glaner, M. F., Moeller, G., ... & Rothacher, M. (2023). MPG-NET: A low-cost, multi-purpose GNSS co-location station network for environmental monitoring. Measurement, 216, 112981.