A mid-latitude cirrus cloud climatology from MPLNET at the Goddard Space Flight Center in Greenbelt, MD
Abstract:Cirrus clouds play a significant role in the Earth’s climate system. Therefore it is important to have highly accurate, quantitative data records of cloud properties that span several years and geographic regions. In the first stage of an upcoming global study, we take a dataset spanning more than eight years (2006-2014) and comprised of over 60,000 hours of continuous lidar data to derive a cirrus cloud climatology for a mid-latitude site in the Micropulse Lidar Network (MPLNET). Using the recently developed version 3 cloud algorithm, macrophysical properties of cirrus clouds, including diurnal, monthly, seasonal, and annual cycles are described for the Goddard Space Flight Center (GSFC) site located in Greenbelt, MD (38.99oN, 76.84oW). The new algorithm uses a combination of two methods and a multi-resolution temporal averaging scheme to detect cloud boundaries. The first method uses gradients in the lidar profile to identify low-level clouds. The second method uses uncertainites in the lidar profile to identify elevated cloud layers (i.e. cirrus). Results are discussed in the context of the region’s synoptic meteorology.
Additionally, the Goddard Earth Observing System-version 5 (GEOS-5) reanalysis is used to to describe the temperature, pressure, wind speed, and wind direction at the cirrus cloud boundaries. Estimates of the cloud extinction and optical depth are also given. Finally, results of this study are compared to previous mid-latitude cirrus climatologies at other geographical regions.