Wintertime Intercomparison of Specific Humidity and Temperature Profiles Measured by Microwave Radiometer (MWR), Radiosonde, and INSAT‐3DR Sounder Over Delhi, India

Abstract Accurate profiling of atmospheric temperature and humidity is critical for weather forecasting, climate studies, and air quality management. This study evaluates wintertime atmospheric profiles of temperature and specific humidity (SH) from three systems over New Delhi, India: radiosondes, a ground‐based microwave radiometer (MWR), and the INSAT‐3DR satellite sounder. Radiosondes serve as the reference standard, offering high vertical resolution but limited temporal coverage. The MWR provides continuous high‐temporal‐resolution observations with good performance in the lower troposphere, while INSAT‐3DR delivers broad spatial coverage and hourly retrievals but with coarser vertical resolution near the surface and reduced accuracy under cloudy conditions. The comparison reveals that MWR profiles agree well with radiosonde observations below 4 km, with root mean square error values of <4 K for temperature and <2.2 g/kg for SH. However, MWR retrievals exhibit near‐surface cold and dry biases of up to −5 K and −1.2 g/kg (∼−25%), respectively. INSAT‐3DR shows good agreement for temperature throughout the levels (bias of <2%). In the 4–10 km altitude range, SH biases are within ∼25%, but show warm and moist biases near the surface exceeding 2 K and 1 g/kg (30%). These results confirm the complementary nature of MWR and INSAT‐3DR: MWR performs best in the boundary layer, while INSAT‐3DR is more reliable in the mid to top troposphere. The study underscores the importance of combining multiple observation platforms to enhance the accuracy of atmospheric profiling for improved numerical weather prediction and environmental modeling.