English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We report on mapping of the north polar region of Mars using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument. We have observed 3 Mars years (28–30) of late winter and spring recessions (L s  = 304°–92°). Our investigations have led to the following observations. (1) We classify the retreat of the north polar seasonal cap into “presublimation,” “early spring,” “asymmetric” and “stable” periods according to the prevalent H 2 O ice grain size distributions. (2) During the early spring, the signatures of CO 2  ice at the edge of the cap are obscured by H 2 O ice, which increases the apparent size of the H 2 O ice annulus around the seasonal CO 2  cap at this time. At around L s  = 25°, this process changes into an asymmetrical distribution of H 2 O deposition, covering CO 2  signatures more rapidly in the longitude range from 90 to 210°E. (3) We detect signatures of “pure” CO 2  ice in extremely limited locations (in Lomonosov Crater) even in midwinter. H 2 O ice signatures appear everywhere in the retreating CO 2  seasonal cap, in contrast with the south polar seasonal cap. (4) We find that average H 2 O ice grain sizes continuously increase from northern midwinter to the end of springtime; this is the inverse of the behavior of CO 2  ice grain sizes in the southern springtime.

Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) north polar springtime recession mapping: First 3 Mars years of observations