Jonathan P. Merrison

Jonathan P. Merrison

orcid

Research Focus & Metrics

Academic Career Length

36Years (1991-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 May 2010 in Journal of Geophysical Research
Verified
Journal Article
Open access
PDF file
CHC. Holstein‐Rathlou
C. Holstein‐Rathlou
HGHaraldur Gunnlaugsson
Haraldur Gunnlaugsson
JMJonathan P. Merrison
Jonathan P. Merrison
KBK. M. Bean
K. M. Bean
BCB. A. Cantor
B. A. Cantor
PTP. A. Taylor
P. A. Taylor
Wind speeds and directions were measured on the Phoenix Lander by a mechanical anemometer, the so‐called Telltale wind indicator. Analysis of images of the instrument taken with the onboard imager allowed for evaluation of wind speeds and directions. Daily characteristics of the wind data are highly turbulent behavior during midday due to daytime turbulence with more stable conditions during nighttime. From Ls ∼77°–123° winds were generally ∼4 m s−1 from the east, with 360° rotation during midday. From Ls ∼123°–148° daytime wind speeds increased to an average of 6–10 m s−1 and were generally from the west. The highest wind speed recorded was 16 m s−1 seen on Ls ∼147°. Estimates of the surface roughness height are calculated from the smearing of the Kapton part of the Telltale during image exposure due to a 3 Hz turbulence and nighttime wind variability. These estimates yield 6 ± 3 mm and 5 ± 3 mm, respectively. The Telltale wind data are used to suggest that Heimdal crater is a source of nighttime temperature fluctuations. Deviations between temperatures measured at various heights are explained as being due to winds passing over the Phoenix Lander. Events concerning sample delivery and frost formation are described and discussed. Two different mechanisms of dust lifting affecting the Phoenix site are proposed based on observations made with Mars Color Imager on Mars Reconnaissance Orbiter and the Telltale. The first is related to evaporation of the seasonal CO2 ice and is observed up to Ls ∼95°. These events are not associated with increased wind speeds. The second mechanism is observed after Ls ∼111° and is related to the passing of weather systems characterized by condensate clouds in orbital images and higher wind speeds as measured with the Telltale.

1 June 2012 in Aeolian Research
Verified
Journal Article
Closed access
JMJonathan P. Merrison
Jonathan P. Merrison

1 November 2007 in Icarus
Verified
Journal Article
Closed access
JMJonathan P. Merrison
Jonathan P. Merrison
HGHaraldur Gunnlaugsson
Haraldur Gunnlaugsson
PNP. Nørnberg
P. Nørnberg
AJA.E. Jensen
A.E. Jensen
KRK.R. Rasmussen
K.R. Rasmussen

1 March 2004 in Planetary and Space Science
Verified
Journal Article
Closed access
JMJonathan P. Merrison
Jonathan P. Merrison
JJJ. Jensen
J. Jensen
Kjartan KinchKjartan Kinch
Kjartan Kinch
RMR. Mugford
R. Mugford
PNP. Nørnberg
P. Nørnberg

6 August 2004 in Science
Verified
Journal Article
Closed access
PDF file
PBP. Bertelsen
P. Bertelsen
WGW. Goetz
W. Goetz
MMM. B. Madsen
M. B. Madsen
Kjartan KinchKjartan Kinch
Kjartan Kinch
SHS. F. Hviid
S. F. Hviid
RGR. Gellert
R. Gellert
The magnetic properties experiments are designed to help identify the magnetic minerals in the dust and rocks on Mars—and to determine whether liquid water was involved in the formation and alteration of these magnetic minerals. Almost all of the dust particles suspended in the martian atmosphere must contain ferrimagnetic minerals (such as maghemite or magnetite) in an amount of ∼2% by weight. The most magnetic fraction of the dust appears darker than the average dust. Magnetite was detected in the first two rocks ground by Spirit.

1 September 2015 in Geomorphology
Verified
Journal Article
Closed access
KRKeld R. Rasmussen
Keld R. Rasmussen
AVAlexandre Valance
Alexandre Valance
JMJonathan P. Merrison
Jonathan P. Merrison