Applying Cloud Climatological Data from the PATMOS-x Record to Study the Great Lakes Region

The complex processes behind the formation of clouds make them difficult to simulate in future climate scenarios, and because of this there have been many studies that employ long-term observational cloud records to better understand their role in Earth’s energy balance. In this study we use one such cloud climate dataset, the Pathfinder Atmospheres Extended (PATMOS-x) record, to monitor the normalized difference vegetation index (NDVI) over the Great Lakes region and identify if there is any ‘greening’ occurring over the last forty years. The region, characterized by its access to freshwater, was focused on due to the abundant amount of farmland available. Monthly clear sky composite images at different cloud probabilities were generated from PATMOS-x, and the NDVI of the land was calculated using the available daytime red and near-infrared channels. It was found that seasonality, orbital drift, cloud contamination, and the number of satellites available over the course of the record were all factors impeding our ability to generate a long-term consistent record of NDVI. Although a clear trend was not detected, this study provides insight into the implications of each of these factors in cloud records and how they affected NDVI calculations.