Correspondences

What is linked, what is not

Each arc joins two phenomena tested on this site. Green and animated: clear link (correlation significant at 5 % after correcting for autocorrelation, or a response outside chance in an event study). Grey: inconclusive test. A statistical link alone does not establish causation.

Clear link
Inconclusive

Hypotheses tested

Clear links

correlation p < 0.05 or epochs outside chance

Causation demonstrated

a correlation demonstrates none

Arc width from |r| of the stored result; several tests between the same phenomena are drawn as stacked arcs.

Hypothesis tested: The atmosphere of Mars is 95 % CO₂, which condenses as frost on the winter polar cap and sublimates in spring: the mass of the atmosphere, hence the surface pressure, follows the seasons. The southern cap, larger (long, cold southern winter near aphelion), makes the deepest minimum (Hess et al., 1980).

Pearson correlation r (lag 0 days)

1.00

95% interval [0.99; 1.00] (block bootstrap)

Aligned points

4,718

effective n ≈ 288 (autocorrelation)

p-value

0.00000

two-sided, Fisher z transform, effective n

Out-of-sample R²

0.989

Martian years 35 to 38 predicted with the fit of years 31 to 34; error 5.7 Pa over 2,527 sols

Seasonal amplitude

21 %

minimum 748 Pa at Ls 154°, maximum 926 Pa at Ls 258°

Equivalent climb of Curiosity (m per year)

69 m

drift of -5.35 ± 0.14 Pa per year, converted with the scale height (11 km)

Period analysed

2012-08-16 → 2026-08-25

computed on Oct 25, 2026 · engine v1.0

Pressure against the season, one curve per Martian year (Pa)

Show the data as a table

Pressure of each sol, corrected for the altitude drift (brought back to the landing-site altitude), against Ls. The years overlap almost perfectly: the climate of Mars repeats from year to year far more faithfully than the Earth’s. The departures around Ls 200–300° come from dust storms (year 34: global storm of 2018).

Aligned series (CSV)

Method and sources

Daily mean pressure of the REMS station on Curiosity; solar longitude Ls of the same sol. Model: constant, two harmonics of Ls (cos Ls, sin Ls, cos 2Ls, sin 2Ls) and a linear drift in time that absorbs the climb up Mount Sharp (pressure drops by about 0.08 Pa per metre). Least-squares fit; out-of-sample test: coefficients estimated on Martian years 31 to 34, pressure predicted for years 35 to 38. Correlation between observed and predicted pressure, effective size from the persistence of the errors, block bootstrap with 30-sol blocks.

Computation parameters

{
    "r": "Pearson correlation between observed and predicted pressure out of sample; effective size n(1 − φ)/(1 + φ) from the lag-1 autocorrelation φ of the out-of-sample errors; block bootstrap (30 sols)",
    "fit": "least squares on all sols; out of sample: fitted on Mars years 31–34 (before 2019-03-23), predicted for the following years",
    "climb": "drift / (p / H), scale height H = 11100 m at Gale (Martínez et al., 2017)",
    "model": "p = a + b1 cos Ls + c1 sin Ls + b2 cos 2Ls + c2 sin 2Ls + d·t (t in years since landing)",
    "mars_years": "counted from Mars year 31 at landing, a new year at each wrap of Ls"
}

Inputs : mars.msl.pressure.daily (4,718 pts, run #3719) · mars.msl.ls.daily (4,745 pts, run #3719)

Reading this result

A spectacular positive control: 99 % of the variance explained by season and altitude alone, and a forecast from one year to the next within a few pascals. The equivalent climb (about 70 m a year, nearly a kilometre since 2012) agrees with Curiosity’s ascent of Mount Sharp; it assumes a steady drift, which the real stepwise ascent is not quite. Correlation is not causation: common factors (seasons, cycles, trends) or coincidence can produce it. The p-values account for autocorrelation (effective n) but not for preprocessing choices; the confidence interval comes from a block bootstrap. The limits of the source data apply.

SOURCES OF THIS PAGE

Curiosity rover REMS daily weather reports, Gale crater (NASA/JPL-Caltech, CAB): Gómez-Elvira, J., et al. (2012). REMS: the Environmental Sensor Suite for the Mars Science Laboratory rover. Space Science Reviews, 170, 583–640. Daily reports of the REMS team, NASA/JPL-Caltech/CAB(CSIC-INTA). · doi:10.1007/s11214-012-9921-1 · source page ↗
Licence : NASA content, public domain; credit NASA/JPL-Caltech/CAB(CSIC-INTA) · retrieved on Oct 25, 2026 · SHA-256 1c3f64aa69ab…
Hess et al. (1980): Hess, S. L., Ryan, J. A., Tillman, J. E., Henry, R. M., & Leovy, C. B. (1980). The annual cycle of pressure on Mars measured by Viking Landers 1 and 2. Geophysical Research Letters, 7(3), 197–200. · doi:10.1029/GL007i003p00197
Licence : Published literature; cited
Martínez et al. (2017): Martínez, G. M., Newman, C. N., De Vicente-Retortillo, A., Fischer, E., et al. (2017). The modern near-surface Martian climate: a review of in-situ meteorological data from Viking to Curiosity. Space Science Reviews, 212, 295–338. · doi:10.1007/s11214-017-0360-x
Licence : Published literature; cited

Martian season and pressure A quarter of the atmosphere of Mars freezes and thaws every year

What is linked, what is not