Which Observations are Needed to Resolve Planetary Boundary Layer Structure?

The Earth’s atmospheric planetary boundary layer (PBL) is the interface between the atmosphere and the surface. Surface – atmosphere mass and energy exchanges crucial to weather and climate occur within the PBL, and mixing between the PBL and the free troposphere has a significant influence on weather and atmospheric composition. While the PBL is of critical importance, there are no systematic global observations of the complex three-dimensional (3D) thermodynamic structure of the PBL.

This presentation will demonstrate the tools we have constructed to conduct quantitative analysis of potential future measurements of the thermodynamic structure of the PBL, including analysis of a wide range of PBL types and measurement methodologies. In particular, we have designed an observing system simulation experiment (OSSE) framework tailored for PBL studies, but adaptable to a diverse set of potential future missions. In contrast to weather forecast OSSEs, which measure the potential impact of measurements on numerical weather prediction, our system addresses the potential benefit of observations to address mission-specific science questions. It includes the following components:

1. Interfaces to a collection of global km-scale and regional sub-km scale nature runs that represent a large range of weather states and PBL structures.
2. Passive (e.g., infrared and microwave) and active (e.g., radar and lidar) instrument simulators capable of exploring trades among the diverse set of PBL measurements.
3. Orbit simulators that can represent constellations of satellites at varying altitudes and with diverse observing strategies.
4. Data fusion techniques that account for measurement uncertainty and optimally combine information from observations with very different spatial and temporal resolutions.
5. A computational framework that parallelizes radiative transfer and retrievals efficiently over diverse compute environments from individual multi-core workstations to distributed high performance computing architectures to the cloud.

We will provide an overview of our OSSE framework, and show the results of experiments designed to quantify information in current observations and the expected observing syste of the 2030s. We also explore the impact of adding measurements not currently available in space.