Clouds strongly affect weather and climate, but they are hard to measure because their particles are unevenly spaced across very small scales. We used a laser-based instrument to observe clouds in very fine detail and found that standard averaging methods can miss important small-scale structure. Our results show when these averages are reliable, when they can break down, and how future instruments could use signals from individual droplets and ice particles to improve cloud measurements.

Two methods were developed to measure the mixed layer height, an important variable for weather forecasting and air quality studies. An aerosol-based method and a thermodynamic method were tested using a lidar system that can measure vertical profiles of aerosols, humidity, and temperature. Each method performed best under different conditions. Together, they provide a path toward more reliable mixed layer height monitoring with a single instrument.

A method is introduced to expand the observational capability of a diode-laser-based lidar system. This method allows the lidar transmitter to change the laser pulse characteristics from one shot to the next. We use this capability to lower the minimum altitude of observation and to observe clouds with higher range resolution.

We show promising results for a new machine-learning based paradigm for processing field-acquired cloud droplet holograms. The approach is fast, scalable, and leverages GPUs and other heterogeneous computing platforms. It combines applications of transfer and active learning by using synthetic data for training and a small set of hand-labeled data for refinement and validation. Artificial noise applied during synthetic training enables optimized models for real-world situations.

For atmospheric science and weather prediction, it is important to make water vapor measurements in real time. A low-cost lidar instrument has been developed by Montana State University and the National Center for Atmospheric Research. We developed an advanced signal-processing method to extend the scientific capability of the lidar instrument. With the new method we show that the maximum altitude at which the MPD can make water vapor measurements can be extended up to 8 km.