# Seasonal Water "Pump" in the Atmosphere of Mars: Vertical Transport to the Thermosphere

## TL;DR

This study uses a general circulation model to simulate a seasonal water pump mechanism on Mars, showing how water vapor is transported upward and across latitudes, especially during dust storms, impacting thermospheric water levels.

## Contribution

It introduces a hydrological cycle scheme into the MPI-MGCM, revealing a seasonal water pump mechanism responsible for vertical water transport on Mars.

## Key findings

- Water vapor is transported upward during southern high-latitude perihelion.
- Dust storms significantly increase thermospheric water abundance.
- The water pump mechanism is driven by meridional circulation and solar tides.

## Abstract

We present results of simulations with the Max Planck Institute general circulation model (MPI-MGCM) implementing a hydrological cycle scheme. The simulations reveal a seasonal water "pump" mechanism responsible for the upward transport of water vapor. This mechanism occurs in high latitudes above 60$^\circ$ of the southern hemisphere at perihelion, when the upward branch of the meridional circulation is particularly strong. A combination of the mean vertical flux with variations induced by solar tides facilitates penetration of water across the "bottleneck" at approximately 60 km. The meridional circulation then transports water across the globe to the northern hemisphere. Since the intensity of the meridional cell is tightly controlled by airborne dust, the water abundance in the thermosphere strongly increases during dust storms.