Limb Correction Effects on TIROS-N Microwave Sounding Unit Observations

Abstract

Evaluations of limb-corrected brightness temperatures computed by NESDIS from TIROS-N MSU observed brightness temperatures are presented. Observed brightness temperatures both before and after limb correction are compared to simulated brightness temperatures derived from conventional radiosonde measurements. Results suggest a left-to-right bias in the limb-corrected MSU data, with the left side colder than the right side. The uncorrected MSU brightness temperatures can be more accurately simulated than those available after the limb correction technique is applied. Incorporating the actual MSU antenna patterns into the simulations removes most of the scan angle dependence in the bias differences.