Spectroscopic imaging of sub-kilometer spatial structure in lower-tropospheric water vapor

The subgrid spatial variability of water vapor is an important geophysical parameter for modeling tropical convention and cloud processes in atmospheric models. This study maps sub-kilometer spatial structures in total atmospheric column water vapor with visible to shortwave infrared (VSWIR) imaging spectroscopy. We describe our inversion approach and validate its accuracy with coincident measurements by airborne imaging spectrometers and the AERONET ground-based observation network. Next, data from NASA's AVIRIS-NG spectrometer enable the highest-resolution measurement to date of water vapor's spatial variability and scaling properties. We find second-order structure function scaling exponents consistent with prior studies of convective atmospheres. Airborne lidar data show that this total column measurement provides information about variability in the lower troposphere. We conclude by discussing the implications of these measurements and paths toward future campaigns to build upon these results.

Automated summary

This study uses VSWIR imaging spectroscopy to map sub-kilometer spatial structures in total atmospheric column water vapor, validating the accuracy of the inversion approach. By measuring the spatial variability and scaling properties of water vapor at the highest resolution to date, consistent second-order structure function scaling exponents were found, providing information about variability in the convective atmosphere.