Perseverance Sends Back Weather Report on Its First Full Martian Year

The Perseverance rover has spent almost two Earth years on Mars, which is just a single Martian year. With a full seasonal cycle in the books, researchers from the University of the Basque Country in Madrid have released the first detailed weather report from Perseverance. The study, published in Nature Geoscience, explores how temperature, wind speed, and atmospheric pressure vary over time in Jezero Crater.

Perseverance is equipped with seven major scientific instruments, including the MEDA (Mars Environmental Dynamics Analyzer). This tool is under the supervision of researcher José Antonio Rodríguez-Manfredi, who works at the university’s Centre for Astrobiology (CAB). MEDA includes sensors that can monitor temperature, pressure, wind speed, humidity, and dust concentrations.

Jezero Crater is near the planet’s equator, but it never gets very warm there. Perseverance reports the average temperature is -67 degrees Fahrenheit (-55 degrees Celsius), but the temperature swings wildly throughout the day, with temperatures between 50 and 60 degrees Celsius warmer during the day than at night. As temperatures drop off at night, so does the wind. The CAB researchers report that heating of the thin Martian atmosphere generates turbulent air movements due to convection. When the sun sets, the air settles. Perseverance recorded strong winds moving to the southeast during the day, reaching speeds of 82 feet (25 meters) per second. In the afternoon, winds dropped to just 13 feet (4 meters) per second, and the wind often died completely from 4 to 6 a.m. local time.

Here, you can see the MEDA sensors extending from the rover’s mast below the iconic ChemCam.

Pressure sensors in MEDA show a marked change throughout the year. The daily thermal cycle causes its own fluctuations, of course, but the melting and refreezing of the planet’s carbon dioxide ice caps produce a denser atmosphere during the Martian summer and a thinner one in the winter.

NASA chose Jezero Crater as the landing zone because there’s a huge ancient river delta inside it that could contain evidence of ancient life. As it turns out, Jezero Crater also has an extraordinary number of whirlwinds (or dust devils, if you prefer) compared with other regions on Mars. Perseverance regularly detected very large whirlwinds measuring more than 328 feet (100 meters) in diameter.

While it’s nice to have a weather report from another world, it’s more than a novelty. A better understanding of the Martian atmosphere will help NASA plan future automated missions, as well as hypothetical future crewed Mars landings. Perseverance can pave the way while it searches for its next prized rock sample.

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