PSL Supports ASTRaL in Australia

Project: Installation of air-sea flux system for ASTRaL
Project leads: Ludovic Bariteau and Elizabeth Thompson

From April 1 to 9, 2024, Ludovic Bariteau of the Data, Instrumentation, and Field Campaigns Division deployed instruments in Fremantle, Australia, on the U.S. Navy Ofﬁce of Naval Research’s Research Vessel Thomas G. Thompson. The deployment lent the Physical Sciences Laboratory's expertise to the Arabian Sea Transition Layer (ASTRaL) 2024 project, led by the Environmental Fluid Mechanics Laboratory at Notre Dame University.

About the installation

Ludovic installed PSL's seagoing air-sea flux system, which quantifies fluxes, including sensible (temperature) and latent (humidity) heat, of momentum (wind stress), shortwave and longwave radiative fluxes, and freshwater flux (evaporation/precipitation).

The main components of the system deployed consist of:

a sonic anemometer that measures the fast fluctuations of the wind,
a motion pack to measure the angular rates and accelerations of the ship to account and correct for the moving effects,
a CO2/water vapor gas analyzer that measures the fast fluctuations of CO2 and water vapor,
an optical rain gauge to measure rainfall,
a temperature/relative humidity sensor,
a surface pressure sensor,
long and short-wave radiometers,
a “sea snake”, a sensor developed at noaa to measure sea temperature near the surface,
a GPS and heading system,
a laser wave meter to measure wave height, and
two micro-barometers to measure the fast pressure fluctuation induced by the waves.

The air-sea flux system deployment is integral to the ASTRaL field campaigns, providing data to address key hypotheses regarding the Mini Warm Pool's formation, evolution, and its interaction with atmospheric and oceanic processes. It will offer insights into how net surface fluxes govern Sea Surface Temperature warming/cooling. Funding from the NOAA Global Ocean Monitoring and Observing Program enables the lab's contribution to this project.

More about ASTRaL

The ASTRaL project aims to investigate the dynamic mechanisms governing the structure and interaction between the ocean and atmospheric boundary layer in the Arabian Sea, with the goal of resolving biases in climate models related to ocean heat, atmospheric moisture, and precipitation. Funded by the Office of Naval Research, the project supports research on the Transition-Layer Physics of the Southeast Arabian Sea Mini Warm Pool phenomenon and its implications on biophysical interactions and monsoon initiation. The study focuses on understanding the lifecycle of Mini Warm Pool, including its development, maintenance, and dissolution.

NOTE: Shortly after installation, the project was shifted to the Bay of Bengal in the Indian Ocean due to security concerns in the Arabian Sea.