2023 NESSI Presentations - Joseph Loffredo

Watch 2023 NESSI intern Joseph Loffredo's end-of-summer presentation, "A Survey of MPD (MicroPulse DIAL) Differential Absorption Lidar Data."

Over the last 20 years there have been repeated calls from various national reports for observing systems that can accurately measure thermodynamic profiles of the atmospheric boundary layer (e.g., National Research Council 2009,2010,2012; National Academics of Sciences, Engineering and Medicine 2018). The MicroPulse DIAL (MPD) was jointly developed by Montana State University and NCAR/Earth Observing Laboratory. It is a differential absorption lidar, meaning that it measures the difference in absorption from two near infrared frequencies, ~828nm (Spuler et al. 2015, 2021). The ratio of returned signals gives a range-resolved water vapor number density (absolute humidity). This technique makes the MPD a perfect answer to the calls of the past and present because it is taking direct measurements, meaning no external calibration is required for the narrow bandwidth frequencies. The instrument has demonstrated high accuracy across numerous studies over the last several years (Weckwerth et al. 2016).

To illustrate MPD water vapor profiles as different atmospheric phenomena passed overhead, a survey of MPD data from field campaigns was conducted. These examples show the value of MPD’s high vertical resolution water profiles and its ability to operate autonomously for long periods of time, showcasing the potential for a network of MPDs.