Assessment of INSAT-3D/INSAT-3DR Derived Atmospheric Motion Vectors Using Wind Profiler Observations Located at Gadanki, India

Abstract

The accurate estimation of atmospheric motion vectors (AMVs) derived using sequences of images from geostationary satellites is very important because of their extensive use in improving initial conditions of the numerical weather prediction (NWP) models. To assess the quality of retrieved AMVs, validation of these winds with ground-based observation is very important. In the present study, the evaluation of AMVs retrieved using the data from geostationary satellites, viz. INSAT-3D/INSAT-3DR, has been carried out with respect to wind profiler data and radiosonde data. The wind profiler used in the present study is an L-band radar lower atmosphere wind profiler and is installed at the National Atmospheric Research Laboratory, Gadanki, located at 13.27° N, 79.10° E. This instrument measures continuous high-resolution wind measurements in the lower atmosphere. The radiosonde data available near Gadanki are used for validation. In this study, normal infrared (IR) AMV derived using 10.5–11.5 μm channel of INSAT-3D and INSAT-3DR satellites and staggering-mode IR AMV retrieved using INSAT-3D/INSAT-3DR combination are used. AMV accuracy assessment was performed for the years 2017 and 2018 by calculating statistical scores, viz. root mean square vector difference, wind speed bias and a number of matching points. In addition, the INSAT-3D/INSAT-3DR AMV and profiler wind data are also used to study the characteristics of low-level jet during active and break period of the Indian summer monsoon of 2017 and 2018. The accuracy assessment through this study shows the usefulness of AMVs for improving the initial conditions in NWP models in future.