The ability to quantify aviation environmental impacts accurately is one of the key enablers for sustainable aviation growth. The Aviation Environmental Design Tool (AEDT) offers the capability to model aircraft operations and quantify the associated environmental impacts in terms of emissions and noise metrics. In a departure, the takeoff ground roll segment has a large contribution to the overall noise footprint from the operation. Discrepancies between modeling assumptions and real-world operations during takeoff ground roll not only lead to inaccuracies in peak noise levels but also affect noise contours throughout the downstream departure operation. This study investigates the modeling assumptions for B737-800 and B737-900 takeoff ground roll at Hartsfield-Jackson Atlanta International Airport (KATL) using high-fidelity real-world flight and surface weather data. Aircraft trajectory, takeoff weight, thrust, and weather conditions are extracted from real-world operations for modeling. This study quantifies the performance and noise differences arising from real-world variability during takeoff ground roll. Additionally, the sensitivity of noise results to inaccuracies during takeoff ground roll is investigated. The outcome of this study is the identification of sources of noise differences arising from modeling assumptions and their relative importance for accurate representation of real-world operations, thereby enabling more accurate noise modeling.