Evaluating the Accuracy of a High-Resolution Model Simulation through Comparison with MODIS Observations

Abstract

Synthetic infrared brightness temperatures (BTs) derived from a high-resolution Weather Research andForecasting (WRF) model simulation over the contiguous United States are compared with Moderate Resolution Imaging Spectroradiometer (MODIS) observations to assess the accuracy of the model-simulated cloud field. A sophisticated forward radiative transfer model (RTM) is used to compute the synthetic MODIS observations. A detailed comparison of synthetic and real MODIS 11-mm BTs revealed that the model simulation realistically depicts the spatial characteristics of the observed cloud features. Brightness temperature differences (BTDs) computed for 8.5-11 and 11-12 mm indicate that the combined numerical model-RTM system realistically treats the radiative properties associated with optically thin cirrus clouds. For instance, much larger 11-12-mm BTDs occurred within thin clouds surrounding optically thicker, mesoscale cloud features. Although the simulated and observed BTD probability distributions for optically thin cirrus clouds had a similar range of positive values, the synthetic 11-mm BTs were much colder than observed. Previous studies have shown that MODIS cloud optical thickness values tend to be too large for thin cirrus clouds, which contributed to the apparent cold BT bias in the simulated thin cirrus clouds. Errors are substantially reduced after accounting for the observed optical thickness bias, which indicates that the thin cirrus clouds are realistically depicted during the model simulation.

Radiance‐Based Evaluation of WRF Cloud Properties Over East Asia: Direct Comparison With FY‐2E Observations

“…Shöne et al () evaluated cloud coverage based on an objective analysis method for the model‐to‐satellite approach. Lee et al () used observed BTs to examine the accuracy of simulated cloud field, but with emphasis on the evaluation of the accuracy of optically thin cirrus clouds. To better perform such evaluation, Greenwald et al () developed an RT simulation system to generate synthetic Advanced Baseline Imager imagery onboard the Geostationary Operational Environmental Satellite.…”

WRF multi‐physics simulation of clouds in the African region

“…However, simulated TCC deviations are the result of a combination of possible errors in different types of cloud, each of which has a different effect on the rest of the simulated variables, depending on their radiative properties. To compare cloud simulations and satellite measurements, in some previous studies a radiative transfer code has been used, computing the synthetic radiances from model simulation results and comparing them with radiances measured by sensors onboard different satellites (Otkin and Greenwald, ; Greenwald et al , ; Garand et al , ; Lakshmanan et al , ; Lee et al , ). Some authors have implemented COSP as a diagnostic tool in regional models, facilitating the comparison of simulated clouds with satellite observations.…”

Real-Time Simulation of the GOES-R ABI for User Readiness and Product Evaluation

“…While we have experience evaluating both synthetic imagery and derived products (Otkin et al 2007;Otkin and Greenwald 2008;Otkin et al 2009;Cintineo et al 2014;Lee et al 2014), this study focuses on the ABI-derived products. The approach in dealing with one of the largest sources of NWP model errors, namely displacement errors in the history.…”