Behavior of IMERG precipitation extremes with temperature at different spatial resolution

Abstract

The Clausius-Clapeyron equation determines how saturation vapor pressure increases with temperature, which is important in determining variations in extreme precipitation. Regionally, the scaling of C–C does not vary significantly, but the relationship with extreme precipitation does. In this study, the precipitation from Integrated Multisatellite Retrievals for Global Precipitation Measurement (IMERG) is tested for its accuracy in scaling extreme precipitation rates with temperature (termed scaling factor). We utilized the IMERG precipitation data across the Indian Sub-continent at 0.1° × 0.1°, 0.25° × 0.25° and 0.5° × 0.5° spatial resolution from 2001 to 2020 datasets. Our findings show that, there is a transition in Global Precipitation Measurement’s precipitation extremes estimations (95th percentile) around 30 °C over spatial resolution of 0.25° and 0.1° from C–C to sub C–C. This study also evaluates the sensitivity of C–C scaling in different regimes of India having homogeneous precipitation climatology. It is found that southeast India is highly sensitive to the spatial resolution, as it shows steep slopes in extreme precipitation rates at high dew point temperatures. This is the first study to evaluate the sensitivity of spatial resolution on C–C analysis as most of the previous studies have considered temporal variations.

Keywords

• IMERG
• precipitation
• temperature
• C–C theorem